Use Of Azalla As A Nitrogen Source Of Lowland Rice*

E1sje L. Sisworo* *, Widjang H. Sisworo**, Havid Rasjid**,Hendratno**, Soleh Solahuddin* *, and Goeswono Soepardi* **

Abstract

Use or Azalia As A Nitrogen Source For Lowland Rice. A four-year experiment has been carried

out to study the possibility of using Azolla as a nitrogen source for lowland rice. The work done inthe first year, experiments were conducted in the wet season (WS) and the dry season (DS) of 1984/1985,was to evaluate whether Azolla could really increase rice yield. In the second year, experiments donein the WS and DS of 1985/1986, N·derived from Azolla (N dfA) and N·derived from urea (N-dfU) in

rice planl were determincd. The third year work done in the WS and DS of 1986/1987 was conducledto sce to what extend Azolla could be applied in the terms of kg N/ha as a N-source for rice. While

the last year was devoted to study the N-balance of Azo/lo and urea, which was done in Ihe DS of1988/1989. Resulls of Ihe experimenls show that Azo/lo has the same ability as urea to increase rice

production. There was no difference in lolal N-uptake by rice treated either with Azolla or urea, orAzalia interacted with urca. By increasing the Azalia level N recovery in rice will decrease. The samephenomenon was also found with urea. Anolher interesting fact is thai an Azolla cover in Ihe rice fieldcould promole N-uptake from urea.

INTRODUCTION

The ability of Azalia to fix N2 from the air has been established by manyresearchers. 'This trait of Azalia in building up its nitrogen content could be usedas an N source for many purposes, such as for lowland rice to increase rice pro­duction. This possibility has been studied in different countries 11-31. Such studiesarc very importal1l because resuJts have shown that Azalia has the possibility toreplace part of chemical fertilizers commonly used for lowland rice. In some extremecases, such as for remote areas, it could be used as a sole N fertilizer source.

In Indonesia the common rate of N used for lowland rice ranges from 60 to90 kg N/ha. In several agricultural areas, the rate used is up to 150 kg N/ha or moreBut higher doses of N-fertilizer does not improve rice yield as shown by the workof Abdullah et al [4,5]. The lack of response to chemical fertilizer shown by thesedata could be attributed to the satiated condition of the soil, caused by using highrates of chemiC<11fertilizers for long periods.

For Indonesia Azalia might improve soil conditions and reduce chemicalN-ferti]izers. Bearing all this in mind a study of Azalla as an N-source was doneduring four years. Another advantage of using Azalla as an N source is that it couldbe used in remote areas, where chemical fertilizers arc not readily available dueto limited transportation.

This paper reports the work done under FAO/IAEA Coordinated ResearchProgramme on Isotopic Studies of Nitrogen Fixation and Nitrogen Cycling in Azalla

and Blue-Green Algae. I~C No. 39271SD for four years to study the possibility ofusing Azalla as an N source for lowland rice.

**

This rcsearch is supponed by the FAO/IAEA Coordinaled Rcsearch Programme on IsOIOpicSiudies of Nilrogen Fixalion and Nitrogen Cycling in Azolla and Bluc-Green Algae. RCNo. 3927/SDCenlcr for the Applkalion of Isolopes and Radi:llion. BATANBogor Agriculture Institull'

15

MATERIALS AND METHODS

Influence of N Source on Rice Production (1984/1985)

Field experiments were conducted in Bogar, West Java. The date of seeding,transplanting, and harvesting are presented in Table 1.

Plots size, plant distance. and variety used are described in Table 2.All the treatments performed in the field experiments are shown in Table 3.

In these experiments. Azalla was applied at a rate of 36 and 72 kg N/ha, at differenttimes Le. before and after transplating. Only labelled urea was used in theseexperiments while the Azalla used was unlabelled.

The main parameter observed was rice production expressed in dry weight ofgrain and straw.

Interaction of N source (1986-1987)

These field experiments were done in Bogar. Date of seeding, planting, andharvesting are presented in Table 1. In Table 2 data for plot size, plant distance,and rice variety used are given. Here Azalla was applied at 60 kg N/ha in twosplits, but since this rate could not be achieved in the field, the rates applied wereusually less than 60 kg N/ha. Labelled Azalla and urea were used in these fieldexperiments. The labelling of Azalla was done in the field by growing Azalla inplots of 3 m X 3 m size and with the addition of labelled urea. The labelled Azalla

was washed, mixed and drain before incorporation. The treatments conducted in these

experiments are presented in Table 4. The parameter used was the nitrogen yield.

Effect of N sources Rate on N-Recovery (1987-1988)

Field experiments were done at Pusaka Negara, West Java, (Tables I and 2),while the treatments are described in Table 5. Here Azalla used ranged from 28.0to 117.2 kg N/ha, while rates of urea were from 30 to 120 kg N/ha. The samelabelling method was used. Parameters applied were N-recovery of N-effeciency ofAzalla and urea.

15N Balance Experiments (1988/1989)

Field experiments were done at Bogar, (Tables 1 and 2). The treatments donein this experiment are described in Table 6. The rate of Azalla application was200 g fresh weight/m2 when used with urea, while urea was applied at rates of30 and 60 kg N/ha. Labelled Azalla was applied at a rate of 33.3 kg N/ha.

The method of Azalla labelling in the field was by growing Azalla in 1/3 partof the experiment plot. After 15N labelled urea was applied to the Azalla cover,it was left to grow for 12 days, th~n was expanded to 1/2 part of the experimentplot. To this Azalla cover, more ])N labelled urea was added. After the second

addition of 15N labelled urea, the Azalla cover was left to grow for 15 days, andfinally was let to expand to the whole experiment plot. The whole labelled Azalla

16

cover was incorporated into the soil. "l11emain parameter here was to establish anN- balance of rice applied with Azalla or urea.

Azolla

Azolla used for all experiments was Azalla pinnata obtained from the National

Biology Institute, Bogor, Indonesia. The percentagc of total-N and the atom excessof Azolla uscd are presented in Tables 7 and 8.

Harvest

In all experiments the rice plants were cut at 3 cm above the soil surface. Paniclewas separated from straw and dried at 60°C for 48 hours.

Total-N was dctermind by Kjeldahl method. For experiments using 15N,

the atom excess of the plant parts were determined using a lASCO NIA-l emissionspectrometer.

UESULTS AND DISCUSSION

Influence of N-Source on Rice Production (1984/1985)

From these experiments it was clearly shown that Azolla has the same abilityas urea to increase rice production (Table 9). The increase of rice production byAzolla as compared to the control, was observed in the dry season (OS) as wellas in the wet season (WS) experiment. Especially for the OS experiment, from thedata obtained it was revealed that Azolla at a lower N-rate gave more rice productionthan urea applied at higher N-rate (Table 9).

By these experiments it was proven that Azolla could be used as a singleN-source or interacted with urea to increase rice production. Similar fact has alsobeen reported by many research workers as mentioned before.

Interaction of N-Som-ce (1986/1987)

For these field experiments, discussion will be focused on the nitrogen yieldof rice. Data in Table J 0 show that the highest N-yield is for NU-3 treatment. ForAzolla alone and Azalla interacted with urea, the nitrogen yield were quite low,particularly in the WS. This might be due to the Azolla N-rate applied, which ingeneral was lower than the N-rate of urea, while for the OS, the difference was less

(Table 4). This is probably because of the nearly equal N-rate application of Azallaand urea (Table 4). The difficulty in applying Azolla at exactly the same N-rates asurea, has also been reported by Eskew and Kovacs (6).

Data in Table 11 show that, there is no difference in total N uptake betweenAzalla, urea, or Azolla interacted with urea. Only for treatment NU-3, there is aquite high total N-uptake. This may be due to the fact that labelled urea was usedtwice Le., at transplanting and at maximum tillering, while for the other treatments,labelled Azolla or urea was only applied once, at transplanting or at maximumtillering.

17

Expressed in mg N/9 hills, total N-uptake dfU was higher. This is due to the highernitrogen yield as presented in Table 10.

In the WS, there were still differences between treatments on N-recovery ingrain, straw, and planL The highest N-recovery was obtained by Azalia wheninteracted with ureaJNAU (Table 12). In the DS, there were no differences inN-recovery in the grain, straw, and planL The higher N-recovery from Azalla canbe used as an indicator that rice plant can use N-dfA better than N-dfU. Anotherpossibility is that more N-dfU is lost than N-dfA from the soil, leaving less N-dfUavailable for rice compared with N- dfA.

Effect of N-Source Rates on N-Uecovery (1987/1988)

In these field experiments, it is obvious that N-rate of Azalia is always lowerthan that of urea (Table 5). Despite of this fact, the N-dfA was higher than N-dfU(Table 13). This might mean that as an N-source, AzalIa is used more efficientlythan urea. Another interesting point is that with the increase of N-source rates, either

Azalia or urea, the N-recovery decreased. 'This probably means that with increasingN rates of Azalia or urea the plant is able to explore other N sources due to increasingroot growth, such as N from the soil, resulting in a decrease of percentage ofN-recoving, both N-dfA and N-dtu.

15N Ualance Experiments (1988/1989)

Data presented ~'1Table 14 show that the lowest N-uptake by rice was fortreatment of 30 NU (1). This happened when urea was applied without an Azallacover. However when urea was applied at a later time, Le. two weeks aftertransplanting, the N-uptake increased (Table 14). An increase of N-uptake was alsoobserved when the N rate of urea was increased. However N-uptake dfA was not toohigh compared to N-uptake dfU.

An interesting fact is that N-uptake dfU could increase when there is an Azalia

cover. As summerized by Fillery et a1. [7] estimated losses of N fertilizer appliedby volatization range from 2 to 47%. This is mainly due to large fluctuations in

pH in the floodwater. According to Roger eLa1.[8]. Large pH i1uctuations wouldoccur when there is a good algal growth. While they [8] stated further thatmeasurements conducted in lRRI showed fairly stable pH of the foodwater underflooting macrophytes such as Azalia or lemna. This finding by Roger et a1. [8] mightbe the answer why in this experiment where an Azalla cover was grown in therice field the N-uptake dfU increased. Total N-uptake in roots were higher in thoselocated at 0-10 cm depth than in deeper roots. For total N in the soil, apparentlymore N was left in 0-10 cm soil layer than in deeper layer Crable 14).

The highest N-recovery percentage in plants were given by treatmentA(Tl) + 30 NU (wat), while for Azalia as a single source represented by treatmentNA(1), the N-recovery was also quite high (Table 15). For the root and soil, thehighest N-recovery was given by the treatment where Azalla was used as a singleN source NA(T) (Table 15). The highest total N-recovery was also from the Azalia

18

treatment NA (1), while the lowest N- recovery was given by the treatment whereurea was applied at transplanting at a rate of 60 kg Njha (60 NUL(1)) (Table 15).

CONCLUSIONS

From this four-year experiment, the following conclusions could be forwardedi.e.

Azolla has the same ability as urea to increase rice yield .Total N-uptake derived from Azolla generally is lower than that derived from Urea.

This might be due to the lower N-rates of Azolla applied compared to thatof urea.

It is difficult to reach high N rates from Azolla. which are equal to those ofurea, especially for rates higher than 60 kg N/ha.The higher the N rates of Azolla and urea used the lower the percentage ofN-recovery. Apparently the plant root growth increase when Azolla or urea wasapplied increasingly, enabling the plants to explore other N-source besides theN-sources already added.An Azolla cover in the rice field can increase N-uptake derived from urea. Thismight be due to fairly stable pH of flood water in the rice field when thereis an Azolla cover.

ACKNOWLEDGEMENT

The authors recognized the help of the Director of the Center for the Applicationof Isotopes and Radiation and the International Atomic Energy Agency for theirsupport to this four-year experiment.

We also thanks the technician of the Soil and Plant Nutrition Group,Ms. Karaliani, Ms. Halimah, Ms. Trimurti, Ms. Elly Radhani, Mr. Tohir andMr. A. Jawanas for their assistance in conducting the experiments.

REFERENCES

1. 1. WATANABE. Microbiology of Tropical Soils and Plant Productivity,Dommerques YR. and Diem H.G., cds. J. Martinus Nijhoff Publishers, TheHague (1982) 169

2. T.A. LUMPKIN and D.L PLUCKNETT, Westview Tropical AgriculturalSeries, No.5, Westview Press, Boulder, Colorado (1982)

3. S. PARTOHARDJONO, V. HENDRIK, and M. BUSTAMAN, Effect of Azolla

incorporation spacing and nitrogen festilizer application in the growth. and yieldof wetland rice, Contribution 69 (1983)

4. N. ABDULLAH, M.M. MITROSUHARDJO, SUWANDI and RUCHY ANA,

Risalah Simposium IV Aplikasi Isotop dan Radiasi, BATAN, Jakarta (1990)555 - 568

5. RUCHY ANA, Risalah Pertemuan Ilmiah Aplikasi Isotop dan Radiasi dalamBidang Pertanian , Peternakan dan Biologi, BAT AN, Jakarta (1991) 143 - 156

19

6. D.L. ESKEW, G.T. KaY ACK, Int. Symp. and Workshop on Nitrogen FixationAssociated with Rice Production (1989) (Submitted)

7. I.R.P. FILLERY, lR. SIMPSON, and S.K. DE DAITA, Soil Sci. Soc. Am.'J48 (4) (1984) 914-920

8. P.A. ROGER, 1.F. GRANT, P.M. REDDY, 1. WATANABE. "Efficiency ofNitrogen Fertilizers for Rice", International Rice Research Institute (1987)43-68

Table 1. Datcs of seeding, transplanting, and harvesting

YearDateof

198411985

SeedingTransplantingHarvesting

wet season

(WS)Nov.6, 1984Nov. 27, 1984March 10, 1985dry season

(DS)May 20, 1985June 11, 1985Sept. 23, 1985

1986/1987 wet season

(WS)Dec. 9, 1985Jan.2, 1986April 15, 1986dry season

(DS)June 9, 1985June 30, 1986Oct.1, 1986

198711988 dry season

(DS)May 22, 1987June 15, 1987Sept.7, 1987wet season

(WS)Nov. 15, 1987Dec.7, 1987March 14, 1987

198811989 dry season

(DS)May 25, 1988June 14, 1988Sept. 13, 1988

Note : After each experiment a residual experiment was carried out

20

Table 2. Experiment site, plot sizer, plant distance, and rice variety used

1984/1985

experimental siteplot size :* yield plot* isotope plotplant distancerice variety

Bogar, 250 m above sea level

5 m x 1.60 m1.60 m x 1.20 m20 em x 20 emAtomita I

Bogar, 250 m above sea level

1985/1986

experimental siteplot size :* yield plot* isotope plotplan! distancerice variety

5 m x

I m x

20 em

lR-36

4 m1m

x 20 em

1987/1988

experimental site

plot size :* yield plot* isotope plotplant distancerice variety

I 988/1989

experimental siteplot size :* yield plot* isotope plotplant distanceriee variety

Pusaka Negma, 5 m abovesea level

3mx3m1mxlm20 em x 20 em1R-64

13ogor, 250 m above se.1 level

5mx4mO.R m x 0.6 m

20 em x 20 emIR-64

Note : both experimental sites. 13ogor and Pustaka Negara are located inwesl Java

21

Table 3. Treatments carried out in the field experiments, 1984/1985

Code of treatment

1. ON Control, no nitrogen

2. 30 NU 30 kg, N/ha urea applied as a basal fertilizer, broadcastedand incorporated

3. 60 NU 60 kg NB/ha urea applied in three splits, 30 kg N/ha beforetransplanting, 30 kg N/ha three weeks after transplanting,and 15 kg N/ha 25 days before heading

4. 90 NU 90 kg N/ha urea applied in two splits, 60 kg N/ha beforetransplanting and 30 kg N/ha 25 days before heading

5. 30NU + 36NA (1) 30 kg N/ha urea and 1.5 kg fresh weight/m2 Azalla (equalto 36 kg N/ha) are simultaneously incorporated into the soilas basal fertilizer. Azalla was planted in the treatment plot.If Azalla has nor reach the quantity of 1.5 kg fresh weight/m2,the deficit was added from outside the treatment plot.

6. 30NU + 36NA (2) 30 kg N/ha urea applied as a basal fertilizer, and Azalla wasadded three weeks after transplanting by incorporation intothe soil, at the rate as in treatment 5. The same step as intreatment 5 was taken when Aza/la has not reached the

required quantity.

7. 72 NA (1) After reaching full cover, Azalla was incorporated'into thesoil before transplanting. After trransplanting Azalla

inoculation was repeated in the treatment plot. The secondincorporation of Azalla was carried out at 25 days beforeheading. The first and second incorporation of Azalla wasat the same rate as in treatment 5, and the same step wastaken as in treatment 5 when Azalla has not reached the

required quantity.

8. 72 NA (2) After reaching full cover, Azalla grown after transplantingwas incorporated into the soil. Directly after the fisrtincorporation Azalla was reinoculated to reach full cover. Thesecond incorporation of Azalla was carried out at 25 daysbefore heading. Both incorporation of Azalla were done ata rate equal to treatment 5, and the same step as in treatment5 was taken when Aza/la has not reached the requiredquantity.

Notes

22

13N labelled urea was used only in the isotope plots- no labelled Azalia was used in the isotope plots.- the same treatments were carried out for the isotope plots as well

as for the yield plots

Table 4. Treatments of field experiments 1986/1987

Wet Season Dry SeasonAzalia

UreaAzaliaUreaCode oft

mttmttmttmt treatment

.................... kg N/ha ....................... Isotope plot0.0

0.00.00.00.00.00.00.0ON28.3'

27.20.00.030.0'23.70.00.0NA-l29.0

21.4 '0.00.029.031.1'0.00.0NA-20.0

0.030.0'30.00.00.030.0'30.0NU-l0.0

0.030.030.0'0.00.030.030.0'NU-20.0

0.040.0'20.0'0.00.040.0'20.0'NU-30.0

21.4'30.00.00.031.1'30.00.0NAU

Yield plot

0.00.00.00.00.00.00.00.0ON

29.027.20.00.027.823.70.00.0NA-Y

0.00.030.030.00.00.030.030.0NU-Yl

0.00.040.020.00.00.040.020.0NU-Y2

0.027.230,00.00.023.730.00.0NAU-Y

Notes:

- t=Azalia and urea applied at transplanting- mt

=Azalia and urea applied al maximum tillering, =labelled Azalia or urea used

Table 5. Treatment of field experiment 1987/1988

Isotope plot

DSWS

AzaliaUreaAzaliaUrea

........... kg N/ha 0.00.00.0 0.0

28.00.029.3 0.0

56.00.058.6 0.0

84.00.087.9 0.0

112.00.0117.2 0.0

0.030.00.030.0

0.060.00.060.0

0.090.00.090.0

0.0120.00.0120.0

Yield plot0.00.00.0 0.0

22.720.027.82 0.0

45.440.055.64 0.0

68.160.083.46 0.0

90.880.0111.28 0.0

0.030.00.030.0

0.060.00.060.0

0.090.00.090.0

0.0120.00.0120.0

Code of treatments

ONAlA2A3A4

UlU2

U3

U4

aNYAIY

A2YA3Y

A4YUIYU2Y

U3YU4Y

Noles:each rate of Azalia and urea was applied in two splits, Le., the first half was

added at transplanting and the olher half alone month after transplantinglabelled Azalia and urea were used in the isotope plots

23

Table 6. Treatments of field experiment 1988/1989

Codes of treatments

ON

30 NU (T)

30 NU (T) + A (T)

A (T) + 30 NU (wat)

A (Tl) + 30 NU (wat)

30 NU (wat)

60 NU (T)

A(T)

Control, no nitrogen

30 kg N/ha urea, incorporated at transplanting, without Azallainoculation

30 kg N/ha urea, incorporated at transplanting, with Azallainoculation but not incorporated 33.3 and 30.4 kg N/ha Azalla,incorporated at transplanting, in the isotope and yield plotsrespectively.

Azalla inoculated at transplanting, at a rate of 200 g freshweight/m2, but not incorporated into the soil. 30 kg N/ha ureawas added at 2 weeks after transplanting.

The same treatment as in treatment 5 was carried out, but

in this treatment Awlla was incorporated into the soil at 4weeks after transplanting. Further Azolla growth was allowedbut not incorporated.

30 kg N/ha urea, added into the flood water at the s~me timeas in treatment 5, without Azolla inoculation.

60 kg N/ha urea, incorporated at transplanting, without Azollainoculation.

Azalla inoculated at transplanting, at rate of 200 g freshweight/m2, but not incorporated and no addition of urea.

24

Notes treatments number 1 to 9 were all applied in the isotope andyield plots.

- 15N labelled urea and Azalia were only used in the isotope plots.

- in the isotope plots 15N labelled urea was used for treatments 2, 3, 5,6, 7, 8, and for treatment 4 15N labelled Azolla was used.

- for treatment 9, unlabelled Azalia was used in the isotope as well asin the yield plots.

Table 7. Percentage of Total-N of Azol/a during four year experiments

N-total

WS DS... % ...

1984/19851985/1986- unJabelied- labelled

1987/1988- unlabelled- labelled

1988/1989- unlabelled- labelled

T3.80"4.08"

3.127'"3.586" •

3.720'MT

3.08"4.20"

3.450' ••3.902' ••

12 d4.1994••••4.2972••••

3.800'T

3.85"4.24"

3.307'"3.637'"

15 d

4.2569••••4.5510••••

MT3.76"4.16"

3.326'"3.667'"

WS = Wet Season, DS = Dry Season, T = Azalia applied at transplanting,MT = Azalia applied at mazimum tillering, 12 d =12 days after Azalia inoculation,15 d = 15 days after Azalia inoculation.• = mean from 4 replicates, •• = mean from 10 replicates,••• = mean from 8 replicates •••• = mean from 4 replicates.

Table 8. Percentage of atom exess N of Azol/a during four your experiments

Atom Excess

1984/19851986/1987

TMT

1987/1988TMT

WS

3.56**3.42**

1.2254" •1.4316**'

.... % ...

DS

4.22"3.46' •

2.4437" •2.6833' ••

1988/1989 12.0376••••15 d -

Notes all abbreviations and signs in this table are identical to that in Appendix 7

25

Table 9. Influence of N-source on rice production

Dry SeasonWet Season

Treatments . GRST GRST

. . . . . . . . . . . . . . kg/ha

.................ON

31533675 30853637

30 NU

40384124 33914377

60 NU

41394059 37224539

90 NU

48894841 36084592

30NU + 36NA (1)

42664129 38844690

30NU + 36NA (2)

38634263 36554896

72 NA (1)

49185185 36034386

72 NA (2)

49434551 37264351

LSD 5%

642ns ns625

CV(%) 10.2110.40 14.459.59

Notes :

GR = Grain,ST = Straw,• = mean of four replications

LSD = Least Significant Difference,

CV = Coefficient of Variation,

ns = not significant

Table 10. Effect of Azolla, urea, and Azolla + urea on nitrogen yield

Wet Season

Dry SeasonTreatments GR

STPLGRSTPL

................. mg N/9 bills .................

ON

1242-407164912715511822

NA-l

1587511209820557422797

NA-2

1448502195021037892892

NU-l1903574247721557912946

NU-2

1861545240622717673030

NU-3

2048552260023138673180

NAU1727477220422426552897

LSD 5%

371ns438346139364

CV (%)

1520 131113 9

Notes :

GR = Grain,ST = Straw,PL = Plant = Grain + Straw,

- = mean of four replications,LSD = Least Significant Difference,

CV = Coefficient of Variation,ns =, not significant.

26

N ...J

Tab

le11

.E

ffec

tof

Azo

lla,

urea

,an

dA

zoll

a+

urea

onto

tal-

Nup

take

We~

Dry

Seas

on

Tre

atm

ents

GR

STGR

STPL

GR

STGR

STPL

upta

keN

-dfA

/N-d

ru

upta

keN

-dfA

/N-d

ru

.....

%...

.

mg

NI9

hills

.....

%...

.m

gN

/9hi

llsO

N-

--

-- -----

NA

-I14

.97'

9.09

2384

628

416.4

213

.63

339

121

460

NA

-2

16.2

616

.95

23586

32115

.91

13.6

333

510

844

3

NU

-l

14.4

311

.22

27765

43214

.97

13.0

532

510

342

8

NU

-2

18.2

521

.47

337

117

449

17.1

414

.29

387

109

496

NU

-3

22.4

923

.07

463

126

589

25.3

220

.80

589

180

769

NA

U

18.0

116

.62

30880

38811

.40

16.0

825

610

636

2

LSD

5%

4.63

3.80

10234

1103.

842.

20III4

011

2

CV

(%)

1815 2

2261

811

1020

2215

Not

es:

-to

tal-

Nup

take

=up

take

from

labe

lled

Aza

lia

orur

ea-

GR

=G

rain

, ST=

Stra

w,

PL=

Plan

t=

Gra

in+

Slra

w,

N-d

fA=

N-d

eriv

edfr

omA

zali

a,-

N-d

ru=

N-d

eriv

edfr

omur

ea, •

=m

ean

offo

urre

plic

atio

ns,

LSD

=L

east

Sign

ific

ant

Dif

fere

nce,

-C

V=

Coe

ffic

ient

ofV

aria

tion

N co

Tab

le12

.E

ffec

tof

Aza

lla,

urea

,an

dA

zall

a+

urea

onN

-rec

over

y"

Wet

Seas

onD

rySe

ason

Tre

atm

ents

N-a

pplie

dGR

STPLN

-app

lied

GR

STPL

mg

NI9

bills

...

.....

%..

....

...m

gN

/9bi

lls...

......

.%

......

...

ON

--

----

--

NA

nl10

1923.

31'

4.54

27.8

610

9039

·85

11.0

541

.90

NA

-276

030.5

011

.10

41.6

011

2029

.94

9.62

39.5

6N

U-l

10802

5.60

6.00

31.6

010

8030

.07

9.56

39.6

3N

U-2

10803

0.76

10.8

441

.60

1080

35.7

910

.59

45.8

8N

U-3

2160

21.4

25.

8127

.23

2160

27.2

48.

3435

.58

NA

U76

0 40.0

110

.42

50.4

311

2022

.89

8.43

32.2

3

LSD

5%

8.21

3.24

9.34

nsns n

s

CV

(%)

19271

619

24 16

Nol

es:

-N

-app

lied

=am

ount

ofla

belle

dA

zali

aor

labe

lled

urea

appl

ied

-G

R=

Gra

in, ST

=St

raw

,PL

=Pl

ant,

'=

mea

nof

four

repl

icat

ions

,L

SD=

Lea

stSi

gnif

ican

tD

iffe

renc

e,-

CV

=C

oeff

icie

ntof

Var

iatio

n.

IV \0

Tab

le13

.E

ffec

tof

Azo

lla

and

urea

rate

son

N-r

ecov

ery

Dry

Seas

onW

eiSe

ason

Tre

atm

ents

N-a

pplie

dGR

STPL

N-a

pplie

dG

RST P

L

mg

NI9

hills

....

....

%.

...

....

mg

N/9

hills

......

...%

......

....

ON

-----

-- -

Al

10082

9.49

·15

.05

44.5

510

5622

.66

18.5

441

.20

A2

2016

17.4

77.

5224

.99

2113

15.2

512

.47

27.7

2

A3

3024

14.6

77.

4622

.13

3169

13.1

710

.16

23.3

3

A4

4032

16.1

07.

4623

.56

4226

12.2

47.

8420

.08

VI

1080

15.3

54.

5119

.86

1080

20.6

512

.89

33.5

4

V2

2160

14.8

76.

7421

.61

2160

15.1

11

1.89

27.0

0

U3

3240

16.7

58.

0524

.85

3240

16.3

511

.96

28.3

1

V4

4320

12.8

46.

0522

.89

4320

14.4

810

.34

24.8

2

LSD

5%

-N

-rat

e5.

722.

106.

523.

592.

303.

94-

N-s

ourc

e3.

62l.3

:;4.

13ns

nsns

-in

tera

ctio

n8.

092.

979.

22ns

3.25 5.

57

CV

(%)

322625

2118 13

Not

es:

-N

-app

lied

=am

ount

ofla

belle

dA

zoll

aor

labe

lled

urea

appl

ied

-G

R=

Gra

in, ST

=St

raw

,PL

=Pl

ant,

•=

mea

nof

four

repl

ica

lions

,L

SD=

Lea

stSi

gnif

ican

tD

iffe

renc

e,-

CV

=C

oeff

icie

ntof

Var

iatio

n,ns

=no

lsi

gnif

ican

t.

(.,) a

Tab

le14

.E

ffec

tof

Azo

lla,

urea

,an

dA

zona

+ur

eaon

tota

l-N

upta

ke

Roo

ts

Soil

Tre

atm

ents

GR

ST (0-

10em

)(

> 11

em)

(0-

10em

)(

> 11

em)

......

......

......

......

......

%...

......

......

......

......

.....

ON

--

---

-30

NU

(T)

15.2

8*14

.4514

.14

8.85

0.76

0.09

30N

U(T

)+

A(T

)

17.8

414

.0611

.45

8.37

0.69

0.02

NA

(T)

20.2

919

.7319

.05

15.3

80.

990.

15

A(T

)+

30N

U(w

at)

23.6

822

.4613

.86

13.3

90.

570.

02

A(T

l)+

30N

U(w

at)

22.9

224

.6614

.91

16.0

60.

650.

07

30N

U(w

at)

30.0

619

.8711

.16

9.96

0.27

0.13

60N

U(T

)

25.8

719

.9517

.15

9.35

0.48

0.22

A(T

)

--- -

--

LSD

5%

4.28

4.72

4.03

3.34

0.20

0.07

CV

(%)

1417

2020

2245

Not

es:

-to

tal-

Nup

take

=up

take

from

labe

lled

Azo

lia

orur

ea-

GR

=G

rain

, ST=

Stra

w,

*=

mea

nof

four

repl

icat

ions

,L

SD=

Lea

stSi

gnif

ican

tD

iffe

renc

e-

CV

=C

oeff

icie

ntof

Var

iatio

n.

~ •....

Tab

le15

.E

ffec

tof

Azo

lla,

urea

,an

dA

zoll

a+

urea

onN

-rec

over

y

Plan

t

Roo

tsSo

il

Tre

aIm

enIs

Gra

nd

GR

STPL

(0-1

0cm

)(

>II

cm)

Tot

al(0

-10

cm)

(>

IIcm

)T

oul

Tot

al

......

......

......

......

......

......

.%

......

......

......

......

......

..

ON

-- --------

30N

U(T

)25

.11'

11.5

036

.61

2M0.

182.

1930

.64

2.88

33.0

271

.82

30N

U(T

)+

A(T

)

32.0

411

.5I

43.5

51.

750.

131.88

25.0

90.

5825

.67

71.1

0..

NA

(T)

36.1

620

.64

56.8

03.

860.

194.

0530

.83

3.60

34.3

394

.35

A(T

)+

30N

U(w

at)

41.5

117

.96

59.4

72.

400.

182.

5823

.64

0.49

24.1

386

.18

A(T

I)+

30N

U(w

at)

39.6

423

.27

62.9

12.

350.

172.

3923

.681.35

25.3

490

.63

30N

U(w

al)

39.5

420

.09

59.6

32.

360.

212.

5710

.27

3.85

14.0

776

.20

60N

U(T

)

25.2

710

.09

35.3

61.

510.

061.57

8.42

2.81

11.2

348

.15

A(T

)

-- --------

LSD

5%

9.69

5.72

13.3

00.

98ns0.

987.

081.

697.

8612

.80

CV

(%)

20241

83043 282

2532

312

Nol

es:

-N

-rec

over

y=

reco

very

from

labe

lled

Azo

lla

orur

rea

-G

R=

Gra

in, S

T=

Stra

w,

PL=

Plan

t,•

=m

ean

from

four

repl

icat

ions

-L

SD=

Lea

stSi

gnif

ican

lD

iffe

renc

e CV

=C

oeff

icci

ent

ofV

aria

tion

ns=

not

sign

ific

ant.