summary of phd thesis contributions to …because the corn crop is cultivated on a very wide surface...

SUMMARY OF PhD THESIS Ing. George Călin Roiban

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Ing. GEORGE - CĂLIN ROIBAN

SUMMARY OF PhD THESIS

CONTRIBUTIONS TO THE IMPROVEMENT OF POST-EMERGENT WEED CONTROL SYSTEM

IN CORN CROP

Scientific coordinator Prof. univ. dr. ing. PETRU GUŞ

CLUJ-NAPOCA 2010

UNIVERSITY OF AGRICULTURAL SCIENCES AND VETERINARY MEDICINE

CLUJ-NAPOCA DOCTORAL SCHOOL

FACULTATY OF AGRICULTURE


1

CONTRIBUTIONS TO THE IMPROVEMENT OF POST-EMERGENT WEED CONTROL SYSTEM

IN CORN CROP

As agriculture developed, the weed categories continuously diversify and adapted to

new conditions of agricultural technique. The result of these permanent adjustments is

observed today in the great survival capacity of weeds, and in the dynamic within certain

species communities; this dynamic is put in evidence by more adapted biotypes, by the

continuous modification of quantitative and qualitative structure of weeding, by including

new species from spontaneous local flora or from other geographical areas.

Having as pre-requisite the efficient control of weed, we consider very necessary the

knowledge of all elements part of the process.

Corn, as the main cultivated plant in the Transylvanian agriculture exploitations,

remains a preoccupation of scientists to permanently improve the culture technologies or

adapt the technology to the modifications occurred in the corn crop habitat, in the specific

machinery system or in the economic interests of this crop.

The corn particular sensitivity to weeding is an open field for herbology research and

for the study of corn crop weed control, in order to find the adequate solutions for every

homogenous ecological area, solutions that will give the effective answer to reduce the

weeding under the damaging level and to farmers’ economic effort.

The new obligations imposed by the European legislation in the field of environment

protection, certified by the modern techniques of plant protections, justify the selection of

the research theme for the PhD thesis, due to the following aspects:

corn crop is still one of the main agriculture crops at national, European and world wide

level;

crop sensitivity to weeding enforces the weed control by effective and rapid methods;

elimination of numerous herbicidal active substances with pre-emergent application

from the approved for use list;

ecological impact with low risk in the case of post-emergent chemical control;


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Possibility of combining the post-emergent methods for weed control with indirect

preventive or agrotechnical methods in order to obtain an integrated system for weed

control in corn crop, economically and ecologically efficient.

Because the corn crop is cultivated on a very wide surface in different pedo-climatic

areas, the weed infestation differs very much in the country. Variations are bigger if we

observe the ratio of certain weed species towards other, the monocotyledonated species

towards the dicotyledonated, the annual towards the perennial etc.; thus, the selection of the

right strategy for weed control has to be made in the real local conditions.

From the considerations that:

the characteristic weed flora for corn is variable in the territory;

the climatic conditions are variable as well;

the herbicide effect can vary – is related to their adequate selection, their

application technique and the weather;

safety of the agro-ecosystem, animal and human health are also variable, in

relation to many natural and anthropic factors, among other things being the right

approach of weed control methods in the agriculture crops;

the profit of corn crop farmers varies depending on the fact that the technological

steps of crop are correctly applied and on the local conditions

By the research carried out for this thesis, I envisage to clarify certain aspects

concerning the specificity of corn crop weeding in Alba County (commune of Noşlac), the

efficacy of the post-emergence weed control strategies for corn crop, the selectivity of

chemical recipes for corn crop cultivated in this area and the preservation of ecological

balance.


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THE PURPOSE OF THE RESEARCH

The main purpose of the research studies is: to elaborate the strategies for post-

emergent weed control in corn crop, which are optimal from technological, economical and

ecological point of view, for the high meadow area of Alba County. In order to achieve this

goal, there is necessary to cover three essential steps, every one with their own specific

scientific and applicative objectives.

These three steps are determined by the three components needed to making efficient

the results of post-emergent weed control in corn crop and the applicability of those results

to extension in agriculture production of the area. Thus, the research made during 2004-

2007 is framed in the following three stages:

⇒ Establishing the competition between weed and corn plants in the specific

experimental conditions;

⇒ Elaboration the strategies of post-emergence weed control for corn crop in high

meadow areas from Alba county;

⇒ Setting the minimal elements for research extension

THE OBJECTIVES OF THE RESEARCH

The first stage of the research studies - establishing the competition between weed

and corn plants in the experimental conditions of Noşlac – envisage the following study

objectives:

Inventory of weeding degree of corn crop from Noşlac area, Alba County.

Establishing the “problem: weed species for this crop culture;

Establishing the correlations between the weeding level of the area crop culture

and the production;

Establishing the correlations between the weeding level of the crop culture and

climate factors of the research years;

Establishing the fluctuation of weeding level during the 4 research years;


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The second stage of the research studies - elaboration the strategies of post-

emergence weed control for corn crop in high meadow areas from Alba County - envisages

the following study objectives:

Stating the basic elements for elaboration of the strategies of post-emergence

weed control

Testing certain chemical and mixed strategies of post-emergence weed control for

corn crop;

Elaboration of strategies of post-emergence weed control for corn crop in high

meadow areas from Alba county, optimal from technological, economical and

ecological point if view

The third stage of the research studies - setting the minimal elements for research

extension - envisages the following study objectives:

Establishing the economic efficiency of weed control technology with associated

herbicides – single treatment;


herbicides –two treatments;


herbicides – single treatment + mechanical hoeing

Establishing the economic efficiency of weed control technology with total

herbicides applied in triticale crop stubble field + single post-emergent treatment

with associated or complex herbicides.


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THE EXPERIMENTAL DEVICE

The researches on improving the strategies for post-emergence weed control in corn

crop developed in a 4 years period: 2004-2007, in a private property field of Noşlac

commune, Alba County, within the framework of bifactorial stationary experiments, settled

after the randomized blocks method, with 28 variants in four repetitions. The total area

surface was 30 sq meters.

The experimental factors and their graduations are:

A. Weed control method: 28 graduations grouped in 4 control technologies and 2

witnesses:

a1 = classical weed control, 3 manual hoeing – control variant no 1

a2 = no weed control – control variant no 2

a3 – a10 = chemical weed control, single post-emergence treatment with

associated herbicide

a11 – a16 = chemical weed control, 2 post-emergence treatments with fractioned

dosage: an early first one (2-3 corn leaves); the second one at 5-6 corn leaves

stage

a17 – a22 = mixed weed control, early treatment (2-3 corn leaves) with associated

or complex herbicides, followed by mechanical hoeing,

a23 – a28 = 2 years chemical weed control, treatment with total herbicides in

triticale stubble field + single treatment with associated herbicides at 5-6 corn

leaves stage.

B. Experimental years: 4 graduations,

b1 = 2004

b2 = 2005

b3 = 2006

b4 = 2007

In order to establish the efficacy in post-emergence weed control, 11 herbicide

products were tested, having different active substances: foramsulfuron + isoxadifen ethyl,


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rimsulfuron, mesotrione, prosulfuron + primsulphuron, 2.4D acid + MCPA+ clopyralid,

bromoxynil + 2.4D (ester), florasulam+ 2,4 D (EHE), bromoxynil octanoate.

The corn cultivation technology in the experimental field comprises:

3 years crop rotation: autumn triticale – corn – potato + sugar beet + vegetables (fig. 1);

Differentiated working system function of applied weed control variants, as follows:

o For the 4 treatment variants in

previous crop stubble field:

triticale harvest (last decade of

July) - stubble field herbicide

application on all area, with

LEONE 36 SL: 4 l/ ha, 14

days after harvesting – (30 t/ha

manure applied in the second

decade of September, in 2003

– rotation 2 and 3 - and in

2004 – rotation 2) – autumn

ploughing at 25 cm depth, in

the last decade of September

or first decade of October – single rotary harrow passing

o For the 4 treatment variants in previous crop stubble field: triticale harvest (last

decade of July) - stubble field herbicide application all over the area, with LEONE 36

SL: 4 l/ ha, 14 days after harvesting – (30 t/ha manure applied in the second decade

of September, in 2003 – rotation 2 and 3 - and in 2004 – rotation 2) - autumn

ploughing at 25 cm depth, in the last decade of September or first decade of October

– single rotary harrow passing

GDU 3,4 (second decade of April) – complex fertilisation – starter fertilisation Cu

N40P40 – single seedbed combination passing in the seeding day (third decade of

April) – seeded with SPC 6 – post-emergence herbicide application + first foliar

fertilisation (stage 5-6 corn leaves) – second foliar fertilisation (at ear corn formation)

– harvest (first decade of October)

The first cycle of the rotation The second cycle of the rotation

Fig. 1. The crop rotation

Anul

2004 2005 2006 2007

Rotation 1

triticale corn Potato+

Sugarbeet+ vegetable

triticale

Rotation 2

corn Potato+


triticale corn

Rotation 3

Potato+


triticale corn Potato+



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o For variants without stubble field herbicide application: triticale harvest (third decade

of July) – remove the stubble field by superficial ploughing (immediately after

harvest) – single disk passing in the first decade of September - 30 t/ha manure

applied in the second decade of September, in 2003 – rotation 2 and 3 - and in 2004 –

rotation 2 – autumn ploughing (first decade of October) – single rotary harrow in

spring (first decade of April) – mineral fertilisation (second decade of April) – single

seedbed combination passing the day before seeding – seeding (third decade of

April) – first hoeing in the 3 hoeing witness variant and post-emergence herbicide

application (second decade of May) – second hoeing in the 3 hoeing witness variant

and post-emergence herbicide application + first foliar fertilisation, at 5-6 corn leaves

stage – third hoeing in the 3 hoeing witness variant and first in the variants with

hoeing after application of associated or complex herbicides (first or second decade

of June) – the second foliar fertilisation - harvest

Fertilisation:

o organic- with fermented manure 30 to/ha starting in autumn 2003 – rotations 2

and 3 – and finishing in autumn 2004 (rotation 1), so that every rotation was

organic fertilised;

o mineral: 2 fractions: first - NPK with ratio formula 15:15:0: - at germination bed

preparation is assured a N40P40 dosage; the second at 6-8 leaves stage with

ammonium nitrate, being assured a total dosage of N70P40K0;

o foliar: 2 fractions of Murtonik 20:20:20 Me: first – at the same time with the

post-emergence herbicide application at 5-6 leaves stage, 2 l/ha dosage; the

second - at ear corn formation, the same dosage.

The field where the experimental plot is organized is a class I quality type, with 86

bonitation points. Soil is an aluviosol calcaric molic coluvic soil type, with a good fertility,

humus content of 3.84% in the first 60 cm, being assured a humus reserve of 161-200 t/ha.

Content of nutritive elements is different in the soil profile, corresponding to an average

supply of total nitrogen, very good supply of potassium and weak supply in phosphorous.

Chemically speaking, the only intervention needed is completion of P reserve.


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The thermal and precipitation regime during the corn vegetation period was different in

the experimental 4 years, thus the spring and development conditions of weed and the spring and

development conditions of corn crop were also different.

Year 2004 was a relatively normal year compared to multi-annual average values,

during the vegetative period of corn crop being registered average thermal deviations of

+0,58 oC, with significant deviations registered in April (+1,0 oC) and June (+1,6 oC) and

precipitation deviations of +62,2 mm. The positive thermal and negative precipitation

deviations were a surprise for the start of corn crop (May and beginning of June), thus

being felt in the weed competition but also the level of production.

Year 2005 was an exceptional year from climatic point of view, being characterised

as extremely rainy and warm (+ 1,2 oC and + 194 mm compared to multi-annual average

values). The corn vegetation period was warm (+0,95 oC compared to m.a.a. values) and

rainy, especially in April, May, August and September; during the whole period of

vegetation a plus of 167,1mm was registered. Over all, the agricultural year 2005 was a

year with pronounced weeding potential.

Year 2006 was a less warm year, compared with the previous years (the annual

average deviation was +0,90C) and less rainy, the sum of precipitations was close to multi-

annual average value (+34,1mm), but very moody, being considered as a year less

favourable for the corn crop start and with negative influence of level of production, but

significant influence, both positive and negative on weeding. Thus, the corn vegetation

period (April-September 2006) can be appreciated as warm (the positive deviation being of

1,10C). The months when significant positive deviations compared to m.a.a. values were

registered were April (+2,20C) and May (+1,9 0C). Low precipitations during April –

September 2006 overcome the normal value by 50,1 mm, which is a deviation much

smaller then the previous years, but with very large fluctuations in precipitations during

corn vegetative period. April was very rainy the first two decades, followed bay a dry May,

when corn crop suffered a little. The rains dropped in the second part of May saved the corn

crop, which passed in optimal conditions the vegetative stages of this period. The dryness in

the first half of May negatively influenced the spring and development of corn crop, but at

the same time, influenced the weeding level, which was lower.


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Year 2007 was a very warm (the m.a.a. deviation was +2,20C) and rainy at the same

time; the sum of precipitations overcome the m.a.a. by 104,4 mm, but the their repartition

was less good for the corn crop. Analyzing the vegetative period of corn in 2007 showed

that was not a very good year for corn crop. The excessive dryness during June and

moderate in July defined the negative influence of this year climate on corn crop yield.

In order to improve the system of post-emergence weed control in corn crop was

important to proper organise the information system, the research data collection and to

make the following determinations:

Determinations of corn specific weeding characteristics in the studied area:

determination of floral compositions, determination of annual and average weeding

degree (number and weight), determination of annual weight of weed species and

establishing their average weight, establishing the weeding fluctuations specific to the

experimental 4 years, establishing the weed species problematic for corn crop cultivated

in the high meadow area of Alba County (the Noşlac area) and not in the last –

establishing the correlations between level of corn productions and level of weeding;

Determination of tested weed control variants efficacy, namely 4 different post-

emergence control technologies: determination of weed control degree, assured in the

first 50-60 days of corn vegetation (corresponding to the 30 days after first herbicide

application determination), annual and 4 years average values; determination of weed

control degree, assured after 65-70 days of corn vegetation period, for every tested

variant (corresponding to the 45 days after first herbicide application determination),

annual and 4 years average values; comparative determinations between the 4 tested

weed control technologies, annual and 4 years average values;

Determination of level of obtained grain productions: annual and 4 experimental years

average determination, comparative analyses of tested weed control variants and of

tested weed control technologies;

Determination of economic efficiency: calculation of production value, production

expenses, total profit, and rate of profit for every tested weed control variant and their

comparative analysis; also, calculation of average profit and average rate of profit for

the tested 4 weed control technologies and comparative analysis;


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RESULTS OBTAINED

The data included in the PhD thesis, obtained from the experimental field during

2004-2007 and interpreted, accordingly to the rules of statistical processing and

interpretation, make possible the formulation of certain conclusions and recommendations

concerning “the improvement of post-emergence weed control system in corn crop”.

Based on the experimental results, I formulated the following opinions, with the

mention that by these results I tried to add something to the knowledge in the field of

weeding specific to the corn crop cultivated in similar areas and of present weed control

methods, specifically their influence on economic indices and the possibility of extension .

PARTIAL RESULTS CONCERNING THE CHARACTERISTICS OF WEEDING IN CORN CROP CULTIVATED

IN NOŞLAC COMMUNE AREA, ALBA COUNTY

The specific weeding of corn crop, in conditions of experimental field from Noşlac,

determined in the 4 years of culture (2004, 2005, 2006 and 2007) reveals a diversified

floristic composition, comprised of species from all four representative groups: annual

monocotyledonous, perennial monocotyledonous, annual dicotyledonous and perennial

dicotyledonous.

The total number of species determined in corn crop during the four experimental

years was 23 (2 annual monocotyledonous, 1 perennial monocotyledonous, 14 annual

dicotyledonous and 6 perennial dicotyledonous), and the annual floristic composition of

corn weed comprises between 18 and 20 species, depending on the year.

The average weeding degree during the research period is very high, around 101,7

plants/sq.m.

The coverage degree of soil with weed at the beginning of corn vegetative period,

calculated as an 4 years average, is appreciated at 26% - a high value, considering the period

in discussion (15-20 days after the spring of corn crop).

In every one of the 4 experimental years, the competition between weed species was

high during the whole period of corn vegetation, the soil potential for weeding being

relatively high, and the climatic conditions being favourable for vegetative development of

weed species and even for late infestations in weed control variants. The strong competition


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of the weed species was observed especially during 2005, and the weakest competition,

established by the general weeding degree and soil coverage was linked to year 2007.

Statistically, the average weeding in the witness plots is significantly different in the

4 studied years (table 1). In year 2005 was observed an increased weeding of witness plots,

statistically very significant compared to year 2004, the increase of weeding in 2006 being

statistically distinct significant compared to year 2004, and in 2007 a decrease statistically

very significant. It can be stated that, besides the dryer climate in 2007, favourable to a

reduced weeding at the beginning of the vegetation period of corn crop, the effect of tested

4 year crop rotation could also be observed.

Table 1.

Evolution of weed growth degree during research period Noşlac, 2004-2007

Curr.no. Year Number of plants/m2

% compared to Control

Differences compared to Control (pl./m2)

Significance

1. 2004 89,00 100 Ctr. Ctr. 2. 2005 164,30 184,60 75,30 *** 3. 2006 97,00 109,00 8,00 ** 4. 2007 66,40 74,60 -22,60 ooo LSD 5% = 4,16 plante/m2

LSD1% = 6,31 plante/m2 LSD 0.1% = 10,13 plante/m2

The representative weed species is the annual monocotyledonous, representing for all

4 years an average of 48,5% from the total weed species present in corn crop. The annual

dicotyledonated species follow, with an average presence of 43,6% and the perennial

dicotyledonous, with an average weeding participation of 13,5% (fig. 2).

It cannot be minimized a certain biological group when its frequency in a hoed crop

is reduced because, by eliminating the competition of the majority group or groups (by

orienting the weed control methods towards those), the low frequency specie can launch

rapidly and enter the competition with the crop (especially when the weed seed reserve of

soil shows potential for infestation with the minority species in vegetation).


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%/total

13,548,5

43,6

0,5

AM AD PD PM

Fig. 2. Average percent of weed groups in corn crop weed growth

(Noşlac, 2004-2007)

In the case of experimental field in Noşlac, Alba County, during the 4 years of

research, statistically, the weight of weed groups significantly modifies (fig. 3). Thus, if in

2004 the annual monocotyledonous species were dominant, significantly increase in 2005

after manure fertilisation of the corn crop and due to very favourable climatic conditions,

then in the next years show a decrease, by 2007 being statistically observed a very

significant decrease compared to the time that experiments began. At the same time there is

registered an opposite evolution for the annual dicotyledonous and perennial species. It is

remarkable that in 2007 the weight of perennial dicotyledonous species reach 20,2%

compared to their weight at the beginning of experiments (11,2%).

0

10

20

30

40

50

60

70

80

90

100

2004 2005 2006 2007

year

num

ber o

f pla

nts/

squa

re m

eter

AM AD PD

Fig.3. Frequence evolution (plants / m2) for the main three groups of weed species in corn crop (Noşlac, 2004-2007)

DL5%=3,83; DL1%=5,80; DL0,1%=9,32

Ctr

**

ooo

-

DL5%=3,46; DL1%=5,25; DL0,1%=8,43

***

**Ctr -

DL5%=2,00; DL1%=3,03 DL0,1%=4,87Ctr. ** --


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Observing the average weight of weed species within the corn crop from the research

field during the 4 years of experiments (fig. 4), the constant apparition of the weed species

in the weeding determination points and also the biological features of the weeds in what

concerns the competition potential, we can consider that 15 weed species are problematic

for the corn crop cultivated in Noşlac area, Alba county: Echinochloa crus-galli,

Chenopodium album, Amaranthus retroflexus, Setaria glauca, Cirsium arvense, Galinsoga

parviflora, Convolvulus arvensis, Sonchus arvensis, Polygonum lapathyfolium, Polygonum

persicaria, Hibiscus trionum, Agropyron repens, Xanthium strumarium, Atriplex patula şi

Chenopodium polyspermum.

%/total

37.9

12.3

8.6

4.4

2.5

2.5

2.5

2.3

2.3

16

0.6 0.50.40.3

0.3

0.32 1.2 110.9

0.90.8 ECHCG

CHEAL

AMARE

SETGL

CIRAR

GALPA

CONAR

SONAR

POLLA

POLPE

HIBTR

AGRRE

XANST

ATRPA

CHEPO

STEME

POLAV

SYMOF

LATTU

RAPRA

CHEHY

LAPCO

RUBCH Fig. 4. Average participation of weed species in corn crop weed growth

(Noşlac, 2004-2007) The negative evolution tendency of weeding characteristics, specific to the corn crop

cultivated in the studied area, can be supported or stopped by the following aspects:

o soil and climate conditions are favourable for the development of weed species

(annual and perennial) that strongly compete with the corn crop and especially for the

species with phased appearance, that practically invade the previous triticale stubble

field or the corn crop in the second part of vegetation period;


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o the massive infestation with annual mono-cotyletonated species, especially

Echinochloa crus-galli and Setaria glauca, that have already a very strong seed

reserve in soil and are species that strongly compete with other weed species, being

present the risk of their negative impact on the cultivated field;

o increase of perennial di-cotyledonated species incidence; they are dryness resistant

during the stressful periods for corn crop or other annual species, and are very hard to

control with corn selective herbicides (especially Convolvulus arvensis, Sonchus

arvensis, Cirsium arvense, Symphytum officinale, etc);

o use of weed control technologies with major impact on slowing the development of

areas occupied with dangerous species (glyphosate in previous crops stubble field);

o agriculture exploitations organisation, in the manner that the applied crop rotations

have a bigger contribution to diminishing the biological reserve of weed species in

soil and at the same time, to improving the fertility conditions of soils.

PARTIAL RESULTS CONCERNING THE EFICACY OF

POST-EMERGENCE WEED CONTROL TECHNOLOGIES IN CORN CROP

By comparing the four tested weed control technologies with the classical weed

control technology, applied in the control variant no 1 (fig. 1 and table 2), in mate matter of

efficacy in weed control in the first 50-60 days of corn vegetation, it can be concluded that:

The 2 years chemical control technology (stubble field treatment with glyphosate and a

post-emergence treatment with associated or complex herbicides) statistically presents

insignificant differences compared to the manual hoeing variant, and assured an average

control percent of 98.03;

The other control technologies have control average values that overcome 90%, but

statistically are significantly different compared to witness variant and the fourth tested

technology;

The 2 years chemical control technology with 2 post-emergence treatments in corn crop is

very close to the mixed control technology with single treatment completed with single

hoeing. To make the difference between the two, the production results and economic

efficiency must be analysed.


15

85

90

95

100

105

1 2 3 4 5 6 7 8number of variant

% c

ontro

l

V1control 1 1st technology 2nd technology 3rd technology 4th technology

Fig.5. Specific curves of average weed control degree (%) accomplished by tested

technologies in the first 50-60 days of corn vegetation (Noşlac, 2004-2007)

Table 2.

Average weed control degree accomplished in tested variants from the four tested technologies in the first 50-60 days of corn vegetation

Noşlac, 2004-2007 Specific variants for weed control technology Curr

No Weed control technology Control I-

3 manual hoeing 1 2 3 4 5 6 7 8 Avera

ge 1. Chemical: single post-

emergent treatment with associated herbicides

99.9

V3

94.3

V4

94.5

V5

94.4

V6

96.5

V7

91.3

V8

96.1

V9

96.7

V10

97.2

94.6 ooo

2. Chemical: 2 post-emergent treatments with associated herbicides in fractionated doses

99.9

V11

91.4

V12

92.8

V13

90.5

V14

92.1

V15

93.7

V16

91.9

- -

92.07ooo

3. Mixed: precocious post-emergent treatment with associated or complex herbicides followed by a mechanical weeding

99.9

V17

89.3

V18

88.8

V19

89.5

V20

94.5

V21

90.0

V22

96.1

- - 91.37ooo

4. Chemical in 2 years: glyphosate-based herbicides applied pre-crop stubble and one post-emergent treatment with associated or complex herbicides

99.9

V23

98.5

V24

98.8

V25

97.6

V26

98.0

V27

97.8

V28

97.5

- - 98.03

-

LSD (p 5%) =1.99% LSD (p 1%) =2.71% LSD (p 0.1%) =3.67%

SD Values 1,99 2,09 2,15 2,20A

A B

C

C


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By adding another 15-20 days to the first period of study, can be concluded (table 3

and fig. 6):

The average control percent values, calculated for every technology and period, decrease

to very significant differences (statistically speaking) compared to witness technology

(three manual technologies). The chemical control technology with a single treatment

with associated herbicides assured just over 80% weed reduction, the other technologies

overcoming 90% reduction;

The glyphosate technology is surpassed (as efficacy) by the third tested technology

(single post-emergence treatment with associated or complex herbicides + a late hoeing).

Even if the percentual differences are small (average of 3,7%), they are all statistically

assured;

As the corn crop is passing through its vegetation period, the glyphosate technology

matches the technology no 2 (repeated treatments with associated herbicides, in post-

emergence):

Table 3.

Average weed control degree accomplished in tested variants from the four tested technologies after 65-75 days of corn vegetation


No Weed control technology Control I -

3 manual hoeing 1 2 3 4 5 6 7 8 Average

1. Chemical: single post-emergent treatment with associated herbicides

98.5

V3

79.5

V4

80.8

V5

81.3

V6

81.7

V7

80.1

V8

81.3

V9

81.3

V10

83

80.8ooo


98.5

V11

90.6

V12

92.3

V13

90.5

V14

91.6

V15

92.9

V16

91.1

- -

91.5ooo


98.5

V17

91.5

V18

90.8

V19

91.8

V20

97

V21

96.1

V22

98.3

- - 94.3ooo


98.5

V23

91.4

V24

92.5

V25

90

V26

90.5

V27

90

V28

89.2

- - 90.6ooo

LSD (p 5%) =2.04% LSD (p 1%) =2.77% LSD (p 0.1%) =3.75%


17

75

80

85

90

95

100


% c

ontro

l

V1 control 1 1st technology 2nd technology 3rd technology 4th technology

Fig.6. Specific curves of average weed control degree accomplished by tested technologies in the first 60-75 days of corn vegetation ( Noşlac, 2004-2007)

Before corn crop harvest, the specific biomass of weed species present in the culture is

the comparing value to appreciate the general efficacy of weed control technologies. It is

remarkable that, compared to classic weed control technology, two other tested control

technologies are statistically very significant: the chemical technology with glyphosate in the

stubble field + post-emergence treatment with associated herbicide and the mixed control

technology comprising post-emergence early treatment with associated herbicides and late

mechanical hoeing (table 4).

By comparing the control degree curves of the entire vegetation period of corn crop

for the 4 tested control technologies (fig. 7), it can be noticed that there are no statistically

assured differences between 3 of them. The exception is the chemical technology with a

single treatment, which is obviously inferior. This statistically homogenisation is possible

due to specific fluctuations in weeding control of every technology during the period of

vegetation.

SD values 2,03 2,14 2,20 2,25

A B

C

C D


18

Table 4.

Average weed control degree accomplished in tested variants from the four tested technologies at the ending of corn vegetation


No Weed control technology Control I -

3 manual hoeing 1 2 3 4 5 6 7 8 Avera

ge


88.3

V3

67.3

V4

77.8

V5

72.0

V6

77.7

V7

73.4

V8

78.3

V9

74.9

V10

77.5

74.4 ooo


88.3

V11

78.2

V12

82.3

V13

77.6

V14

81.3

V15

84.1

V16

80.0

- -

80.6 ooo


88.3

V17

80.4

V18

78.5

V19

81.3

V20

86.8

V21

84.2

V22

88.0

- - 83.2o


88.3

V23

86.5

V24

89.0

V25

82.6

V26

84.2

V27

79.1

V28

78.6

- - 83.3o

LSD (p 5%) =4.06% LSD (p 1%) =5.51% LSD (p 0.1%) =7.48%

65

70

75

80

85

90


% c

ontro

l

V1 control technology 1 technology 2 technology 3 technology 4

Fig.7. Specific curves of average weed control degree accomplished by tested technologies

at the ending of corn vegetation (Noşlac, 2004-2007)

SD values 4,05 4,26 4,38 4,48

A B

B

B

C


19

Compared and analyzed between them, the control degree diagrams for every of the

three periods of determination, specific to the four weed control technologies in corn crop

(fig. 8, 9, 10 and 11) show differences between the technologies, namely the fields limited

by the control degrees on every determination period and the whole vegetation period of

corn.

For the first technology tested for all 8 control variants, we can observe the obvious

reduction of the second moment observation area (45 days after herbicide treatment)

corresponding to a 65-75 days interval in the vegetation period of corn, compared to the first

observation moment (corresponding to first 50-60 days of corn vegetation). Also, the area

corresponding to the third observations moment for control degree (end of vegetation period

of corn crop) is much diminished. Therefore, the good and very good weed control assured

by this chemical technology is very short in time.

% of weed control

94,3

94,5

99,9

94,4

96,5

91,3

96,1

96,7

97,2

79,5

80,8

98,5

81,3

81,780,1

81,3

81,3

83

67,3

77,8

72

84,8

77,773,4

78,3

74,9

77,5

60

65

70

75

80

85

90

95

100V1

V3

V4

V5

V6V7

V8

V9

V10

30 days45 daysat the harvest

Fig. 8. Weed control degree accomplished by first technology variants in

the three moments of determinations (Chemical weed control: single post-emergent treatment with associated herbicides)

LSD (p5%) = 4.85 % LSD (p1%) = 6.67 % LSD (p0.1%) = 9.19%

Ctr.

ooo

ooo

ooo

oo

oo

ooo

ooo

oo


20

The diagram presented in fig. 9, specific to the second chemical technology of weed

control (comprised by two post-emergence treatments, from which one is an precocious

one) reveals a good and very good efficacy of treatments for both moments of

determination, corresponding to first 65-75 days of vegetation period, before harvesting

showing a plus in efficacy owed to cumulating effects of the 2 treatments).

% of weed control

91,491,9

92,8

99,9

93,7

92,1 90,5

90,5591,1

92,3

98,5

92,9

91,55 90,5

78,280

82,3

88,3

84,1

81,377,6

60

70

80

90

100V1

V11

V12

V13V14

V15

V16

30 days 45 days at the harvest

Fig. 9. Weed control degree accomplished by the second technology variants in the three moments of determination (Chemical weed control: two post-emergent treatments with

associated herbicides in fractionated doses)

For the third control technology, tested in 6 variants, comprising a single precocious

post-emergence treatment with associated or complex herbicides and a late hoeing (fig. 10),

the two moments for efficacy appreciation, covering the period of maximum sensitivity of

corn crop to weeding, are practically confounded because of the control degrees which are

very close; thus, with this technology, the corn crop is saved from weed competition,

included those with belayed spring. For this technology is observed the biggest girth of the

area for control established at the end of vegetation period of corn.

LSD (p5%) = 1.44 % LSD (p1%) = 2.01 % LSD (p0.1%) = 2.84%

Ctr.

ooo

ooo

oooooo

ooo

ooo


21

% of weed control

89,3

99,9

88,8

89,594,5

90

96,1 91,5

98,5

90,8

91,897

96,1

98,388,3

80,4

78,5

81,386,8

84,2

88

60

70

80

90

100V1

V17

V18

V19V20

V21

V22

30 days 45 days at the harvest

Fig. 10. Weed control degree accomplished by the third technology variants in the

three moments of determinations (Mixed weed control: precocious post-emergence treatment with associated or complex

herbicides followed by a mechanical weeding)

For technology IV (fig. 11), one can observe high values of control degree, registered

in the first determination, correlated to decrease of general weeding compared to control

variant, due to herbicide treatment in previous crop stubble field; during the vegetation

period of corn crop is observed a relatively constant decrease of control degree, measured

on 6 variants, some of them over passing the 3 hoeing witness at the determination moment

no 3. It is worth to mention that for this technology the level of control remains around 90%

at the determination moment no 2 (day 65-75 in the vegetation period) and over 80% at the

determination moment no 3 (before harvest) in most of the variants.

LSD (p5%) = 2.18% LSD (p1%) = 3.05 % LSD (p0.1%) = 4.31%

ooo

ooo

ooo

ooo

o

o

Ctr.


22

% of weed control after 30 days, 45 days and at the harvest

98,5

98,8

99,9

97,698

97,8

97,5

91,4

92.5

98,5

9090,5

90

89,2

86,5

89

82,6

88,3

84,2

79,1

78,6

60

65

70

75

80

85

90

95

100V1

V23

V24

V25V26

V27

V28

Fig.11. Weed control degree accomplished by the fourth technology variants in the three moments of determinations

(Chemical weed control in two years: glyphosate-based herbicides applied pre-crop stubble and one post-emergent treatment with associated or complex herbicides)

PARTIAL RESULTS CONCERNING THE INFLUENCE OF CONTROL TECHNOLOGIES TESTED ON CORN CROP YIELD

The average crop yields registered in witness variants are 6884 kg/ha in control

variant I – classical weed control with 3 manual hoeing and only 932 kg/ha in control

variant for weeding (V2 – no hoeing).

The crop yields obtained in the variants within the chemical control technology for

corn crop with a single post-emergence treatment framed in the interval 4720 kg/ha –

variant 3 (EQUIP OD 2 l/ha + CALLISTO 0.2 l/ha) and 6320 kg/ha – variant 10 (TITUS

25DF 30 g/ha + BUCTRIL UNIVERSAL 0.8 l/ha).

-

LSD (p5%) = 3.90% LSD (p1%) = 5.47 % LSD (p0.1%) = 7.73 %

-

oo

oo

oo

Ctr.


23

The crop yield difference against control variant with 3 hoeing is statistically very

significant for most of the tested chemical control variants, except the 2 variants that used

associations of different antigraminee herbicides to antidicotyledonous herbicide BUCTRIL

UNIVERSAL 0.8 l/ha. For these variants the yield difference against the witness is under

800 kg corn grains/ha.


corn crop with two post-emergence treatments framed in the interval 5980 kg/ha - variant

11 (EQUIP OD 1 +1.5 l/ha + BROMOTRIL 40EC 0.6 + 0.6 l/ha) and 6385 kg/ha - variant

15 (TITUS 25DF 20 + 20 g/ha + MUSTANG 0.5 + 0.5 l/ha). Except the first variant

mentioned, in all other variants tested in this technology, the crop yields obtained overcome

6000 kg/ha, being considered better variants than those tested in the first technology. The

production yield differences against the witness variant I (3 manual hoeing) are lower then

those registered with the chemical control technology for corn crop with a single post-

emergence treatment, framing between 499 kg/ha (V15 - TITUS 25DF 20 + 20 g/ha +

MUSTANG 0.5 + 0.5 l/ha) and 904 kg/ha (V11 - EQUIP OD 1 +1.5 l/ha + BROMOTRIL

40EC 0.6 + 0.6 l/ha.

The crop yields obtained in the variants within the mixed control technology for

corn crop with a precocious post-emergence treatment with complex or associated

herbicides and a belayed mechanical hoeing, framed in the interval 6320 kg/ha - variant 18

(BASSIS 25 g/ha + Trend 0.1% and mechanical hoeing) and 6740 kg/ha - variant 22

(TITUS 25DF 30 g/ha + RING 80WG 20g/ha + Extravon 0.15l/ha and mechanical hoeing).

In all variants tested with this technology, the production yields obtained are very close to

control variant I yield, the registered differences being statistically insignificant for 3 of

them: V22 (TITUS 25DF 30 g/ha + RING 80WG 20g/ha + Extravon 0.15l/ha and

mechanical hoeing ), V20 (EQUIP OD 2 l/ha + RING 80WG 20g/ha + Extravon 0.15l/ha

and mechanical hoeing) and V17 ( TITUS PLUS 300 g/ha and mechanical hoeing); for the

other 3 variants tested, the differences are statistically significant for DL values p5% - 450

kg corn grains/ha.

It is worth to mention also for yields obtained the variants comprising associations of

anti-graminee herbicides, very efficient in Noşlac conditions, and between complex


24

herbicides and TITUS PLUS herbicide (300 g/ha). These associations, along with the

belayed mechanical hoeing, acquire a prolonged control in weeding specific to corn crop.


corn crop with two treatments: first one, in the previous crop stubble field with glyphosate

based herbicides and the second, post-emergence treatment (at 5-6 corn leaves) with

complex or associated herbicides, framed in the interval 6362 kg/ha - variant 28 (LEONE 36

SL 4l/ha in stubble field + BASSIS 25 g/ha + Trend 0.1%) and 6800 kg/ha - variant 24

(LEONE 36 SL 4l/ha in stubble field +TITUS 25DF 30 g/ha + Trend 0.1% + BUCTRIL

UNIVERSAL 0.8 l/ha). The production yield differences against the witness variant I are

framed between kg/ha (V24) and 384 kg/ha (V25).

By comparing all variants for weed control tested with the control variant I (3 manual

hoeing), one can observe the variants from the chemical control technology with 2

treatments: first one, in the previous crop stubble field with glyphosate based herbicides and

the second, post-emergence treatment (at 5-6 corn leaves) with associated herbicides,

followed by mixed control technology: a precocious post-emergence chemical treatment

(with associated herbicides, especially anti-graminee) and a belayed mechanical hoeing

(Table 5).

Four of the variant for weed control tested obtained a corn grains production close to

control variant I, the differences between variants or between variants and witness are

statistically insignificant. These variants are:

1) V24: LEONE 36 SL 4l/ha applied in stubble field +TITUS 25DF 30 g/ha + Trend

0.1% + BUCTRIL UNIVERSAL 0.8 l/ha applied in post-emergence;

2) V22: TITUS 25DF 30 g/ha + RING 80WG 20g/ha + Extravon 0.15l/ha + belayed

mechanical hoeing;

3) V23: LEONE 36 SL 4l/ha applied in stubble field + EQUIP OD 2l/ha + Extravon

0.15l/ha + BUCTRIL UNIVERSAL 0.8 l/ha applied in post-emergence and

4) V26: LEONE 36 SL 4l/ha applied in stubble field +TITUS 25DF 30 g/ha + Trend

0.1% + CALLISTO 0.2 l/ha. For all these variants, the average control percent,

calculated for the entire vegetation period of corn crop, surpasses 90%.


25

Table 5. Weed control efficacy and corn crops yield accomplished in all of tested variants, compared to first

control variant with 3 manual hoeing Curr.no Number

of variant Weed control variant Average

control % Significance Yield

kg/ha Significance

1 V1 Control I-3 manual hoeing 95.6 Mt 6884 Ctr. 2 V3 EQUIP OD: 2 l/ha + CALLISTO 0.2 l/ha 80.4 ooo 4720 ooo 3 V4 EQUIP OD: 2 l/ha + RING 80 WG 20

g/ha + Extravon 0,15 l/ha 84.4 ooo 5300 ooo

4 V5 EQUIP OD: 2 l/ha +LONPAR: 2l/ha 86.6 ooo 5400 ooo 5 V6 EQUIP OD: 2 l/ha + BUCTRIL

UNIVERSAL 0.8 l/ha 85.3 oo 6130 ooo

6 V7 TITUS 25DF: 30g/ha (+Trend) + CALLISTO 0.2 l/ha

81.6 ooo 5020 ooo

7 V8 TITUS 25DF: 30g/ha + RING 80 WG 20 g/ha + Extravon 0,15 l/ha

85.2 oo 5850 ooo

8 V9 TITUS 25DF: 30g/ha + LONPAR: 2 l/ha 84.3 ooo 5800 ooo 9 V10 TITUS 25DF: 30g/ha (+Trend)

+ BUCTRIL UNIVERSAL: 0.8 l/ha 85.9 oo 6230 ooo

10 V11 EQUIP OD: 1 + 1,5 l/ha + BROMOTRIL 40 EC 0,6 + 0,6 l/ha

86.7 oo 5980 ooo

11 V12 EQUIP OD: 1 + 1,5 l/ha + MUSTANG: 0,5 + 0,5 l/ha

89.1 o 6275 ooo

12 V13 EQUIP OD: 1 + 1,5 l/ha + CALLISTO 0,2 + 0,2 l/ha

86.2 oo 6260 ooo

13 V14 TITUS 25DF:20+20g/ha (Trend) +BROMOTRIL 40 EC 0,6 + 0,6 l/ha

88.3 o 6290 ooo

14 V15 TITUS 25DF: 20 + 20g/ha (Trend) + MUSTANG 0,5 + 0,5 l/ha

90.2 - 6385 oo

15 V16 TITUS 25DF: 30g/ha (+Trend) + CALLISTO 0.2 + 0.2 l/ha

87.7 o 6130 ooo

16 V17 1) TITUS PLUS: 300 g/ha 2) mechanical hoeing

87.1 oo 6520 o

17 V18 1) BASSIS: 25g/ha (Trend 0,1%) 2) mechanical hoeing

86.0 oo 6380 ooo

18 V19 1) EQUIP OD: 2,0 l/ha + BROMOTRIL 40 EC 0,8 l/ha 2) mechanical hoeing

87.5 o 6365 oo

19 V20 1) EQUIP OD: 2 l/ha + RING 80 WG 20 g/ha (+ Extravon 0,15 l/ha) 2) mechanical hoeing

92.8 - 6500 o

20 V21 1) TITUS 25DF: 20 g/ha (Trend) + BROMOTRIL 40 EC 2) mechanical hoeing

90.1 - 6400 oo

21 V22 1) TITUS 25DF: 30g/ha + RING 80 WG 20 g/ha (+ Extravon 0,15 l/ha) 2) mechanical hoeing

94.1 - 6740 -

22 V23 1) LEONE 36 SL: 4 l/ha 2)EQUIP OD: 2 l/ha +BUCTRIL U. 0.8 l

92.1 - 6730 -

23 V24 1)LEONE 36 SL: 4 l/ha 2) TITUS 25DF: 30g/ha (+Trend) +BUCTRIL UNIV: 0.8 l/ha

93.5 - 6800 -

24 V25 1)LEONE 36 SL: 4 l/ha 2)EQUIP OD: 2 l/ha +CALLISTO 0.2 l

91.1 - 6500 o

25 V26 1)LEONE 36 SL: 4 l/ha 2) TITUS 25DF: 30g/ha (+Trend) + CALLISTO 0.2 l/ha

90.1 - 6580 o


26

Curr.no Number of variant

Weed control variant Average control %

Significance Yield kg/ha

Significance

26 V27 1)LEONE 36 SL: 4 l/ha 2)TITUS PLUS: 300 g/ha

89.0 o 6420 oo

27 V28 1)LEONE 36 SL: 4 l/ha 2)BASSIS: 25g/ha (+Trend 0,1%)

88.4 o 6362 ooo

LSD (p 5%) = 6.15 % LSD (p 1%) = 8.20 % LSD (p 0.1%) = 10.68 %

LSD (p 5%) = 293 kg/ha LSD (p 1%) = 388 kg/ha LSD (p 0.1%) = 502 kg/ha

Between the control degree obtained in tested variants and the corn grains production

is established a very significant positive correlation: r = 0.859*** (fig. 12), and the linear

regression equation allows the calculation of production depending on achieved control

degree. Thus, for an average weed control of 75%, in Noşlac conditions, the production that

can be obtained is calculated with the formula y = 125.59 x – 4884.1 de 4535.15 kg/ha.

y = 125,59x - 4884,1r = 0.859***

4500

5000

5500

6000

6500

7000

78 80 82 84 86 88 90 92 94 96 98

% of weed control

yiel

d kg

/ha

Fig.12. The relationship between weed control degree (%) accomplished in tested

variants and the corn crop yield (kg/ha)

As a result of multiple comparisons with Duncan test, we can observe the following:

4 of the tested weed control variants are in the leading positions in production

classification, with differences between them (including witness variant), statistically

insignificant. These variants are: 1) V24: LEONE 36 SL 4l/ha applied in stubble field

+TITUS 25DF 30 g/ha + Trend 0.1% + BUCTRIL UNIVERSAL 0.8 l/ha applied in

post-emergence; 2) V22: TITUS 25DF 30 g/ha + RING 80WG 20g/ha + Extravon

0.15l/ha + belayed mechanical hoeing; 3) V23: LEONE 36 SL 4l/ha applied in stubble

field + EQUIP OD 2l/ha + Extravon 0.15l/ha + BUCTRIL UNIVERSAL 0.8 l/ha

applied in post-emergence and 4) V26: LEONE 36 SL 4l/ha applied in stubble field


27

+TITUS 25DF 30 g/ha + Trend 0.1% + CALLISTO 0.2 l/ha. Three of these variants

pertain to weed control technology no IV, the success being granted by the culture

hygiene achieved with herbicide LEONE 36 SL – 4l/ha applied in previous triticale

stubble field and by the efficacy of combinations of herbicides applied post-emergence

in the corn crop (especially BUCTRIL UNIVERSAL 0.8 l/ha applied in association with

TITUS 25DF 30 g/ha + Trend 0.1% or EQUIP OD 2l/ha + Extravon 0.15l/ha or the

combination between 2 graminicide herbicides: TITUS 25DF: 30g/ha + RING 80 WG

20 g/ha + Extravon 0,15 l/ha completed with a belayed mechanical hoeing.

3 variants: V20: EQUIP OD: 2 l/ha + RING 80 WG 20 g/ha (+ Extravon 0,15 l/ha) +

mechanical hoeing; V17: TITUS PLUS: 300 g/ha + mechanical hoeing and V25: LEONE

36 SL: 4 l/ha + EQUIP OD: 2 l/ha +CALLISTO 0.2 l, are near the leading variants by

means of the obtained crop production, but statistically are significant different only

from the witness variant I – 3 manual hoeing.

Another 3 tested variants for weed control: V27: LEONE 36 SL: 4 l/ha + TITUS PLUS

300g/ha; V21: TITUS 25DF: 30g/ha + Trend 0.1% + BROMOTRIL 40EC 0.8 l/ha +

mechanical hoeing and V19: EQUIP OD: 2 l/ha + BROMOTRIL 40EC 0.8 l/ha +

mechanical hoeing, obtained crop productions very close to those mentioned above

0

10

20

30

40

50

60

70

V1

V2

4

V2

2

V2

3

V2

6

V2

0

V1

7

V2

5

V2

7

V2

1

V1

9

V1

5

V2

8

V1

8

V1

4

V1

2

V1

3

V1

0

V6

V1

6

V1

1

V9

V8

V5

V4

V7

V3

V2

q/ha yield

Fig. 13. Variants of weed control classification depending on corn crop yield


28

PARTIAL RESULTS CONCERNING THE ECONOMIC EFFICIENCY OF IMPROVED TECHNOLOGIES FOR POST-EMERGENCE WEED CONTROL IN

CORN CROP

In the general classification of profit obtained from all 28 tested variants, the variant

22, component of weed control technology no III, occupied the first place; in this variant

were tested 2 anti-grass herbicides associated (TITUS25DF 20 g/ha and RING 80WG 20

g/ha), followed by a belayed mechanical hoeing.

For the first 13 variants in the classification, the average weed control is framed

between 85.3% (V14) and 94.1% (V22), the crop production obtained is framed between

6290 kg/ha (V14) and 6800 kg/ha (V24), and the profit between 1367.96lei/ha (V26) and

1589.59 lei/ha (V22). From all 26 variants tested (2 being control variants), the profit

obtained is under 1000 lei/ha only for 4 variants, all in the first tested technology (chemical

– a single post-emergence treatment). In these variants, the average percent of control

frames between 80.4 (V3) and 86.6 (V5), and the registered crop yields are all under 6000 de

kg/ha.

In the first 13 variants in the classification we can find all 6 variants from the mixed

weed control technology (single precocious post-emergence treatment – at 2-3 corn leaves,

followed by a belayed mechanical hoeing), 4 variants from the 2 years chemical technology

(glyphosate treatment in the previous crop stubble field and a post-emergence treatment in

corn crop with associated or complex herbicides), 2 variants from the chemical control

technology with 2 post-emergence treatments with fractioned doses herbicides

(combinations between TITUS 25DF 20+20 g/ha and MUSTANG 0.5+0.5 l/ha or

BROMOTRIL 40EC 0.6+0.6 l/ha) and a variant from chemical technology with a single

post-emergent treatment at 5-6 corn leaves stage (variant 10 association of TITUS25DF 30

g/ha and BUCTRIL UNIVERSAL 0.8 l/ha).


29

Table 6.

Variants classification depending on accomplished total profit Classification

Number of variant

Weed control variant Average weed control %

Yield kg/ha

Total Profit lei/ha

Segnificance

1 V22 1) TITUS 25DF: 20g/ha + RING 80 WG 20 g/ha (+ Extravon 0,15 l/ha) 2) mechanical hoeing

94.1 6740 1589.59 A

2 V24 1)LEONE 36 SL: 4 l/ha 2) TITUS 25DF: 30g/ha (+Trend 0.1%)

+BUCTRIL UNIV: 0.8 l/ha

93.5 6800 1575.81 A

3 V17 1) TITUS PLUS: 300 g/ha(Trend 0,1%) 2) mechanical hoeing

87.1 6550 1521.59 AB

4 V21 1) TITUS 25DF: 20 g/ha (Trend 0,1%) + BROMOTRIL 40 EC 0.8 l/ha 2) mechanical hoeing

90.1 6400 1515.79 AB

5 V10 TITUS 25DF: 30g/ha (+Trend 0,1%) + BUCTRIL UNIVERSAL: 0.8 l/ha

85.9 6230 1487.85 AB

6 V20 1) EQUIP OD: 2 l/ha + RING 80 WG 20 g/ha (+ Extravon 0,15 l/ha) 2) mechanical hoeing

92.8 6500 1476.59 ABC

7 V18 1) BASSIS: 25g/ha (Trend 0,1%) 2) mechanical hoeing

86.0 6320 1468.84 ABC

8 V23 1) LEONE 36 SL: 4 l/ha 2)EQUIP OD: 2 l/ha +BUCTRIL U. 0.8 l + Extravon 0,15 l/ha

92.1 6730 1457.56 ABCD

9 V15 TITUS 25DF: 20 + 20g/ha (Trend 0,1%) + MUSTANG 0,5 + 0,5 l/ha

90.2 6385 1409.46 ABCD

10

V19 1) EQUIP OD: 2,0 l/ha +Extravon 0,15 l/ha+ BROMOTRIL 40 EC 0,8 l/ha

2) mechanical hoeing

87.5 6365 1396.79 ABCD

11 V28 1)LEONE 36 SL: 4 l/ha 2)BASSIS: 25g/ha (+Trend 0,1%)

88.4 6362 1384.21 ABCDE

12 V14 TITUS 25DF:20+20g/ha (Trend0,1%) +BROMOTRIL 40 EC 0,6 + 0,6 l/ha

88.3 6290 1373.64 ABCDE

13 V26 1)LEONE 36 SL: 4 l/ha 2) TITUS 25DF: 30g/ha (+Trend0,1%)

+ CALLISTO 0.2 l/ha

90.1 6580 1367.96 ABCDE

14 V27 1)LEONE 36 SL: 4 l/ha 2)TITUS PLUS: 300 g/ha (+Trend0,1%

89.0 6420 1350.83 BCDE

15 V6 EQUIP OD: 2 l/ha + BUCTRIL UNIVERSAL 0.8 l/ha +Extravon 0,15 l/ha

85.3 6130 1309.85 BCDEF

16 V12 EQUIP OD: 1 + 1,5 l/ha + Extravon 0,15 l/ha + MUSTANG: 0,5 + 0,5 l/ha

89.1 6275 1259.46 CDEFG

17 V8 TITUS 25DF: 30g/ha + RING 80 WG 20 g/ha + Extravon 0,15 l/ha

85.2 5850 1256.25 CDEFG

18 V25 1)LEONE 36 SL: 4 l/ha 2)EQUIP OD: 2 l/ha +CALLISTO 0.2 l

91.1 6500 1244.96 DEFG

19 V9 TITUS 25DF: 30g/ha (+Trend 0,1%) + LONPAR: 2 l/ha

84.3 5800 1171.18 EFG

20 V11 EQUIP OD: 1 + 1,5 l/ha + BROMOTRIL 40 EC 0,6 + 0,6 l/ha

86.7 5980 1123.76 FG

21 V16 TITUS 25DF: 30g/ha (+Trend0,1%) + CALLISTO 0.2 + 0.2 l/ha

87.7 6130 1075.58 GH

22 V13 EQUIP OD: 1 + 1,5 l/ha + CALLISTO 0,2 + 0,2 l/ha

86.2 6260 1045.96 GH

23 V4 EQUIP OD: 2 l/ha + RING 80 WG 20 g/ha + Extravon 0,15 l/ha

84.4 5300 898.25 HI


30

Classification

Number of variant

Weed control variant Average weed control %

Yield kg/ha

Total Profit lei/ha

Segnificance

24 V5 EQUIP OD: 2 l/ha +LONPAR: 2l/ha + Extravon 0,15 l/ha

86.6 5400 888.05 HI

25 V7 TITUS 25DF: 30g/ha (+Trend 0,1%) + CALLISTO 0.2 l/ha

81.6 5020 718.25 I

26 V3 EQUIP OD: 2 l/ha + CALLISTO 0.2 l/ha + Extravon 0,15 l/ha

80.4 4720 435.25 J

27 V1 Control I-3 manual hoeing 95.6 6884 166.22 K28 V2 Controls II – no hoeing 0.00 932 0.00 K

SD Values lei/ha: 186.18 196.1 175.45 ...................... 230.83 231.04 231.25

RECOMMENDATIONS FOR TECHNOLOGIES AND VARIANTS FOR WEED CONTROL IN CORN CROP, TECHNOLOGICALLY, ECOLOGICALLY AND

ECONOMICALLY EFFICIENT

Taking into account that in the experimental field the annual monocotyledonous

weed species are in majority, is very important the rigorous control of those species in the

first part of corn crop vegetation, and the belayed hoeing only completes the efficacy of

weed control of perennial and annual dicotyledonous species which are not affected by

herbicides.

The late infestations are much better controlled by hoeing, compared to fractioned

herbicide treatments, applied in periods previous to hoeing. If the second moment for weed

control (chemical or mechanical) in the vegetation period of corn crop is belayed, the

weeding is much lower in the second part of vegetation period. Because the moment of

herbicides application is limited by the vegetative phase of corn (maximum 6 leaves), the

second chemical treatment cannot be pushed further in time, while the hoeing can be carried

out later.

The average rate of profit classifies the tested weed control technologies as follows:

Technology no III (mixed control technology for corn crop with a precocious

post-emergence treatment and a belayed mechanical hoeing), with an average

rate of profit of 86.45%;

Technology no IV (2 years chemical weed control with a total action herbicide

treatment in the previous crop stubble field and a post-emergence treatment in

corn crop), with an average rate of profit of 74.3%;

Technology no II (chemical control technology for corn crop with two post-

emergence treatments), with an average rate of profit of 64.72%


31

Technology no I (chemical control technology for corn crop with a single post-

emergence treatments), with an average rate of profit of 51.97%.

Table 7.

Comparative analysis of weed control technologies depending of the rate of profit

rate of profit %)% Classification

Weed control technologies classification 1 2 3 4 5 6 7 8 Average Signific.


V17

86.8

V18

86.9

V19

77.5

V20

82.1

V21

90.8

V22

94,6

- - 86.45

A


V23

76.4

V24

86.4

V25

62.1

V26

71.2

V27

72.7

V28

77.0

- - 73.3

AB


V11

60.2

V12

67.1

V13

50.2

V14

77.6

V15

79.1

V16

54.1

- - 64.72

BC


V3

22.6

V4

51.3

V5

49.0

V6

74.6

V7

39.0

V8

75.3

V9

67.7

V10

89

51,97

C


5.1 D

SD Values ( %) 13.5 14.19 14.6 14.92

The variants recommended for corn crop farmers from Noşlac area are, tided up from

profit point of view:

• V22: TITUS 25DF 30g/ha + RING 80WG 20g/ha +Trend 0.1% + belayed mechanical

hoeing, with a total profit of 1589.59 lei/ha;

• V24: LEONE 36SL 4l/ha in previous crop stubble field + TITUS 25DF 30g/ha +Trend

0.1% + BUCTRIL UNIVERSAL 0.8 l/ha – post-emergence, with a total profit of

1575.56 lei/ha;

• V17: TITUS PLUS 300g/ha + Extravon 0.15 l/ha + belayed mechanical hoeing, with a

total profit of 1521.59 lei/ha,


32

• V21: TITUS 25DF 30g/ha + Trend 0.1% BROMOTRIL 40EC 0.8 l/ha + belayed

mechanical hoeing, with a total profit of 1515.79lei/ha,

• V10: TITUS 25DF – 30g/ha + Trend 0.1% + BUCTRIL UNIVERSAL – 0.8 l/ha, with a

total profit of 1487.85 lei/ha;

• V20: EQUIP OD – 2l/ha + RING 80WG 20g/ha +Extravon 0.15l/ha + belayed

mechanical hoeing, with a total profit of 1476.59 lei/ha, and

• V18: BASSIS 25g/ha + Trend 0.1% + belayed mechanical hoeing, with a total profit of

1468.84 lei/ha

• V23: LEONE 36SL 4l/ha in previous crop stubble field + EQUIP OD – 2l/ha + Extravon

0.15 l/ha + BUCTRIL UNIVERSAL 0.8 l/ha – post-emergence, with a total profit of

1457.56lei/ha,

• V15: TITUS 25DF 20+20g/ha + Trend 0.1% + MUSTANG 0.5+0.5 l/ha with a total

profit of 1409.46 lei/ha;

• V19: EQUIP OD 2l/ha + Extravon 0.15l/ha + BROMOTRIL 40EC 0.8 l/ha + belayed

mechanical hoeing, with a total profit of 1396.79lei/ha,

• V28: LEONE 36SL 4l/ha in previous crop stubble field +BASSIS 25g/ha + Trend 0.1%

post-emergence, with a total profit of 1384.21 lei/ha,

• V14: TITUS 25DF 20+20g/ha + Trend 0.1% BROMOTRIL 40EC 0.6+0.6 l/ha with a

total profit of 1373.76lei/ha and

• V26: LEONE 36SL 4l/ha in previous crop stubble field + TITUS 25DF 30g/ha +Trend

0.1% + CALLISTO 0.2l/ha – post-emergence, with a total profit of 1367.96 lei/ha.

The results included in the thesis confirm the opportunity for applying the weed

control method in post-emergence in corn crops cultivated in high plane areas from Alba

County.

The positive impact of some variants or weed control technologies on weeding

characteristics, corn crop development, grains production and profit is a very good motif to

recommend these variants to corn crop farmers from Alba County and elsewhere.

summary of phd thesis contributions to …because the corn crop is cultivated on a very wide surface...

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