agronomic and economic analysis of guar (cyamopsis

Agronomic and Economic Analysis of Guar (Cyamopsis Tetragonoloba L.) in

Comparison to Drought Tolerant Crops Adapted to the Texas High Plains

by

Robert Kelby Imel, B.S.

A Thesis

In

PLANT AND SOIL SCIENCES

Submitted to the Graduate Faculty

Of Texas Tech University in

Partial Fulfillment of

the Requirements for

the Degree of

MASTER OF SCIENCES

Approved

Dr. Dick Auld

Chair of Committee

Dr. Noureddine Abidi

Dr. Ryan B. Williams

Mark Sheridan, Ph.D.

Dean of the Graduate School

May, 2015

Texas Tech University, Robert Kelby Imel, May 2015

ii

Acknowledgements

I would like to thank Dr. Dick Auld for always showing me that it always matters

to stop and enjoy what you do while learning new things. His guidance has taught me

more in the last four years than I could have learned in any class through our trips across

campus, to the field, and across the country. I would also like to thank Dr. Noureddine

Abidi for having enough patience to deal with me while learning the chemical makeup of

many different biopolymers and bioproducts. Finishing off my committee, I would like

to thank Dr. Ryan B. Williams for taking time out of his busy days to sit down with me,

and chat about everything happening. He has been a great mentor since originally

teaching me optimization, and now helping me with all things economics.

I would like to thank Loren Casey Davis, Bralie Hendon, Travis Witt, Deepika

Mishra, Tiago Zoz, Mateus Olivo, and all other student workers who have helped me

finish this project along the way. All of you are the reason that makes it fun and

satisfying to come to work each day. I would like to thank Dr. Steve Oswalt, without him

giving me my job at the Texas Tech Quaker Research Farm, I would not be in the

position to finish my masters and start my doctorate program, while opening many new

doors for opportunities.

Finally, I would like to thank my family for all of the backing and love over the

years. Especially, my wife, Alayna, she has been by my side and has always encouraged

me to reach my dreams no matter how big or small.


iii

Table of Contents

Acknowledgements ........................................................................................................... ii

Abstract ............................................................................................................................. iv

List of Tables .................................................................................................................... vi

List of Figures .................................................................................................................. vii

I. Introduction ................................................................................................................... 1

II. Literature Review ........................................................................................................ 7

Overview ..................................................................................................................... 7

Guar............................................................................................................................. 7

Guar as a Forage Crop ................................................................................................ 9

Guar Market .............................................................................................................. 10

Other Alternative Crops ............................................................................................ 11

III. Materials and Methods ............................................................................................ 13

Field Study ................................................................................................................ 13

Disease Rating .......................................................................................................... 14

Forage Rating ............................................................................................................ 14

Break-Even Price Analysis ....................................................................................... 16

Pivot Profit Maximization......................................................................................... 16

IV. Results and Discussion ............................................................................................. 18

Guar Field Study ....................................................................................................... 18

Economic Analysis ................................................................................................... 23

V. Conclusions ................................................................................................................. 35

Bibliography .................................................................................................................... 37


iv

Abstract

Cotton (Gossypium hirsutum L.) has long been the most profitable crop on the

Texas High Plains, but with depleting Ogallala Aquifer levels, water-efficient, alternative

crops have never had a stronger presence. Proceeding many years of a devastating

drought, supplemental irrigation has not been sufficient to make a sustainable cotton

crop. Many producers need to see results of profitability before including alternative

crops such as guar, sorghum, and sesame into their current crop rotations. Guar,

sorghum, and sesame are all able to grow with sustainable yields on dryland during

average precipitation years, but the Texas High Plains never has a normal year of

precipitation. This grand challenge calls for a need to decrease supplemental irrigation

on current cotton crops, and drive home the idea of growing water-saving crops for

generations to come or what we call sustainability.

The objective was to conduct guar agronomic trials in Lubbock, Texas during the

2013 and 2014 growing seasons to determine: 1) cultivars adapted to drip irrigation; 2)

guar lines resistant to foliar disease; 3) and finally perform an economic analysis to

determine sustainability of guar, sorghum, and sesame on the Texas High Plains.

Two different, agronomic trials were planted at Lubbock, Texas on subsurface

drip irrigation. Seventy-four experimental cultivars with five commercial cultivars were

compared under drip irrigation for seed yield, seed size, and foliar disease resistance.

While nine advanced cultivars with four commercial cultivars were compared under drip

irrigation for seed yield, forage yield and value (2014), seed size, and foliar disease

resistance. Economic analysis was performed to compare the break-even price of guar,


v

sesame, and sorghum to compete with an average two-bale cotton crop, and also the most

profitable, water efficient crop-mix for a circle irrigation pivot.


vi

List of Tables

4.1 Advanced Breeding Lines Yield, Disease Rating, Seed Size ..................................... 20

4.2 Experimental Breeding Lines Yield, Disease Rating, Seed Size ................................ 21

4.3 Forage Index for Advanced Breeding Lines ............................................................... 22

4.4 Economic Return per Acre for Cotton, Guar, Sesame, and Sorghum ........................ 24

4.5 Break-Even Price for Cotton, Guar, Sesame, and Sorghum ....................................... 24


vii

List of Figures

1.1 Texas High Plains Area ................................................................................................ 2

1.2 Ogallala Aquifer Rate of Drawdown ............................................................................ 3

3.1 Guar Injury Rating ...................................................................................................... 15

4.1 Area Allocation for Unlimited Water, Irrigation Costs, and Labor ............................ 29

4.2 Area Allocation for Low Water and Average Labor ................................................. 30

4.3 Area Allocation for High Water and Low Labor ........................................................ 31

4.4 Area Allocation for Low Irrigation Costs and High Labor......................................... 32

4.5 Area Allocation for Low Irrigation Costs and Low Labor ......................................... 33

4.6 Area Allocation for an Average High Plains Producer ............................................... 34


1

Chapter I

Introduction

The southern portion of the Ogallala Aquifer has experienced substantial declines

in saturated thickness due to extensive irrigation usage to produce field crops in this

region. Production of traditional crops on the Texas High Plains has been increasingly

constrained by water availability. Additionally, the continued desertification of this

region resulting from climatic changes and extreme recent drought periods are

exacerbating these irrigation constraints (Almas, Colette, et al., 2004). Farmers in this

semi-arid region are beginning to experiment with new methods to conserve water. One

such method has been to incorporate drought tolerant crops in rotation with normal,

staple crops (Auld, Trostle, et al., 2013).

The Texas High Plains consists of 54 counties spreading from the top of the Texas

Panhandle to the Midland-Odessa Region, which covers almost 137,000 square

kilometers (53,000 sq. mi.) (Figure 1.1) (Johnson, 2010). The agricultural industry in this

region generates ~$9 billion yearly including both livestock and crops. The Texas High

Plains is a diverse and growing region with almost one million people (Bureau, 2010).

Urban water requirements increase as population climbs, meaning that the conservation

of water for the future of this region will remain extremely important over the next 50

years.


2

The main aquifer for the Texas High Plains is the Ogallala Aquifer, which covers

an area from South Dakota to the southern portion of the Texas High Plains, making it

the largest groundwater system in North America (Zwingle, 1993). This aquifer covers

90,500 square kilometers (35,000 sq. mi.) (Urban, Kromm, et al., 1992). In 2009

according to the U.S. Geological Survey, 3 billion acre-feet of water was still contained

in the entire aquifer. But saturated thickness was decreasing at a rate of 30 cm (1 ft.) per

Figure 1.1 The Texas High Plains represents 54 counties shown within the box. (http://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Texas_counties_map.png/600px-

Texas_counties_map.png)


3

year on the Texas High Plains. Over the last few years there has been higher than normal

depletion levels often exceeding 60 cm (2 ft.) per year of saturated thickness due to the

drought (Galbraith, 2013). Different areas of the aquifer are experiencing varying rates

of depletion, but the Texas High Plains is seeing the highest rate of depletion (Figure

1.2). This high level of depletion was due to producers having to pump more water to

compensate for lower amounts of precipitation on high water-consuming, historical crops

Figure 1.2 The rate of Ogallala Aquifer drawdown from pre-development to 2007.

(http://texaslandscape.org/maps_ogallaladrawdown/)


4

such as peanuts and corn. Reduction of this high water usage has caused regional water

management boards across the state to start limiting water usage per well to a certain

amount of acre-feet annually based on the county’s historical water usage, normal crop

rotation, and water availability estimated by saturated thickness in the aquifer. Many

counties are easing into these restrictions over the next few years by steadily decreasing

the amount of water availability until limits of just 300 mm/ha (1 acre-foot/acre) per year

giving a total available irrigation of 1973 cm per ha (1920 acre-in.) for an entire 65 ha

(160-acre) field. Some farms do not currently even have the capacity to pump this much

because of the historic decline in saturated thickness. If high water use crops are kept as

the primary crop and planted on the majority of acres, yields will suffer greatly in dry

years with only 30 cm per ha (12 acre-inches) of supplemental irrigation annually.

Guar (Cyamopsis tetragonoloba L.), an annual legume that requires only ~ 23-30

cm (9-12 in.) of irrigation that has traditionally been grown in India and Pakistan. It is

now under renewed interest regionally domestically due to use of guar gum in hydraulic

fracturing (Undesander, Putnam, et al., 1991). Guar is well adapted to West Texas due to

the similar semi-arid climatic conditions of the Texas High Plains and the Thar Desert

region of India and Pakistan where guar originated. Domestic oilfield service companies

such as Halliburton, Schlumberger, and Baker Hughes are paying high prices to import

guar gum to the United States (Kapur, 2012). However, if guar is to become a viable

alternative crop on the Texas High Plains, there needs to be evidence of both grower

profitability and production sustainability.


5

Sorghum (Sorghum bicolor L.) has long been used as cattle feed, but with

biofuels being used in greater quantities, its demand as an energy food stock has been

steadily increasing since the early 2000s (Wilkins, 2015). Due to policy changes, there

has been a decrease in corn based ethanol production. In light of these changes, many

producers are seeking alternative crops, mostly sorghum, to use in ethanol production.

Sorghum dwarf varieties have been developed to conserve water and to improve the

production of sorghum on the High Plains (Tietz, 2012). Through these developments,

sorghum has produced higher yields per acre, while ultimately conserving precious water

sources (Carter, Hicks, et al., 1989).

Sesame (Sesamum indicum L.), an annual oilseed crop, has been one of the

longest cultivated crops in history (Oplinger, Putnam, et al., 1990). The high-value oil

has high oleic acid content and the meal also has a high protein content making it great

feed for livestock (Oplinger, Putnam, et al., 1990). Sesame has historically been hand-

harvested due to seed shatter. Breeding advances have generated non-shattering sesame

varieties that retain seed during high winds and mechanical harvesting. Sesame is also

extremely water efficient, being able to make a profitable crop with only 30 cm (12 in.)

of supplemental irrigation.

It appears that since water conservation on the Texas High Plains will be

inevitable that guar, sorghum, and sesame, will provide great alternatives to peanuts and

corn. Cotton is the most prominent crop on the High Plains, and will probably never be

completely replaced by other crops due to high levels of profitability. Our hypothesis is

that these three highly drought tolerant crops can compliment the cotton grown in this


6

region to provide new options for conservation of our limited aquifer. The hypothesis

was tested through biological field tests of guar, as well as economic analysis of net

income and break-even prices of guar, sorghum, and sesame against cotton.


7

Chapter II

Literature Review

Overview

Guar, sesame, and sorghum have been found in previous research to be extremely

drought tolerant, but there are still unanswered economic and agronomic questions

surrounding guar (Poats, 1960). For alternative crops to be a sustainable option on the

Texas High Plains, they need to show a continuous profitability while reducing water

consumed from the aquifer.

Guar

Guar (Cyamopsis tetragonoloba L.) is a drought tolerant legume that originated in

the Thar Desert of India and Pakistan (Undesander, Putnam, et al., 1991). Guar has long

been used as a livestock crop in the Thar Desert, which contributes to its local name of

“cow food” in Hindu. While it has been used as forage, guar is mainly grown in recent

history for its galactomannan gum. This gum is found in the endosperm which accounts

for about 30% of the seed weight (Sabahelkheir, Abdalla, et al., 2012). This gum is used

in food as a thickener, toothpaste, explosives, and more commonly used in the oil and gas

industry during hydraulic fracturing. When water is added to a refined guar gum, it

creates a thick gel that makes fracturing underground, geological formations more

efficient (King, 2008). Globally, guar acreage has increased in recent years due increased

demand for guar gum by the oil and gas industry by horizontal drilling combined with

hydraulic fracturing. In the last year, the acreage has significantly decreased due to oil


8

prices falling and a Texas guar processing company that filed for bankruptcy (Ledbetter,

2015). Once oil prices rise and hydraulic fracturing resumes, guar should see resurgence

in demand and grower prices.

Guar has long been grown as a catch crop on the Texas High Plains after a failed

cotton crop due to weather events (Wallace, Jones, et al., 2007). A catch crop uses the

nutrients, herbicides, and irrigation applied on the primary crops to make a small profit

on failed land. Guar is a short season crop requiring about 90-120 days to full maturity

depending on variety (Undesander, Putnam, et al.). The short growing season of guar

makes it a prime candidate as a catch crop. However, guar can also be a great full-season

or rotation crop with its low input and irrigational requirements. Crops that follow guar

in crop rotations have shown increased yields up to 15% (Tripp, Lovelace, et al., 1977).

Guar is extremely water efficient and can make a profitable crop in all but

extreme drought years due to its long taproot (Undesander, Putnam, et al.). Guar can

yield from ~335 kg/ha (300 lb/ac) on dryland acreage to over ~2240 kg/ha (2000 lb/ac)

on irrigated acreage with average yields of around 1350 kg/ha (1200 lb/ac) (Undesander,

Putnam, et al.). Guar requires about 300 mm (12 in.) to 400 mm (16 in.) of irrigation to

grow a profitable crop (Dennis and Ray, 1982), while cotton and corn require at least

~800 mm (32 in.) (Brouwer and Heibloem, 1986) and ~900 mm (36 in.) of irrigation

(Howell, Yazar, et al., 1994), respectively. While guar uses less water, it also requires

reduced inputs to produce a crop such as cotton. Few herbicides are labeled for guar, but

dinitroaniline herbicides are currently used as preemergent weed control; 2,4-DB has also


9

been shown to be a great post-plant herbicide to control broad-leaf weeds, but has not

been labeled (Olson, Sij, et al., 2007).

Guar has a few problems that still need to be solved before it can become a

sustainable crop on the Texas High Plains. Problems such as disease from Alternaria leaf

spot, lack of nodulation to fix nitrogen in soils, and a lack of stable markets both globally

and domestically. Alternaria leaf spot, caused by Alternaria brassica, Alternaria

cyamopsidis, and Alternaria cumerina (Orellana and Simmons, 1966), has been a serious

problem of existing varieties. In recent years (2013 and 2014) most of the precipitation

has come in very large rain events over short intervals toward the end of the season. The

combination of moisture, lower-than-average temperatures, and cloud cover sometimes

leads to Alternaria leaf spot in guar (Orellana and Simmons, 1966). Efforts to breed new

cultivars resistant to these strains of Alternaria leaf spot were initiated at Texas Tech

University in 2011.

Since guar is a legume, but few nodules have been found on guar roots grown in

Texas High Plains (Trostle, 2001). It is now thought that the rhizobium that causes

nodulation is not found in the soil of this region. Limited nodulation has also been

contributed to the high pH (7.5-9.0) of the soil found in Texas (Trostle, 2001). More

research is needed to identify the correct rhizobia and developing effective inoculation

methods required for guar nodulation.

Guar as a Forage Crop

If a guar is struck with disease, there is an option to swath the crop during

flowering to make forage crop. Although disease does not have to be prevalent to cut the


10

crop, it could be another option for producers to help with the adoption of the crop. Since

this could be an option, forage value needs to be taken into account through dry yield,

crude protein percentage (CP), acid detergent fiber (ADF) percentage, neutral detergent

fiber (NDF) percentage, and then a total nutrient percentage (Robinson, Putnam, et al.,

1998).

For an accurate measurement to be taken, all forage samples should be dried to

give a basis of results. The dry yield gives a total amount of the biomass of the plant

after being completely dried; this measurement also calculates the amount of water in the

sample when having a weight taken soon after harvest (Henning, Lacefield, et al., 1991).

Crude protein is a percentage measurement calculated from the nitrogen in the sample,

and helps show how much energy is in each sample for livestock (Robinson, Putnam, et

al., 1998). Acid detergent fiber and neutral detergent fiber are related, but acid detergent

fiber is a subset of neutral detergent fiber. Neutral detergent fiber is a measure of the

fibrous portion of the sample, which would contain the hemicellulose, cellulose, and

lignin (Robinson, Putnam, et al., 1998). Acid detergent fiber is a measure of the

indigestible parts of the sample that would include lignin, cellulose, and silica (Henning,

Lacefield, et al., 1991). Total nutrient percentage is just a measure of the overall

digestibility and energy provided to the livestock from the sample.

Guar Market

The limited market and lack of adequate processing, has been the biggest hurdle

for expanded for guar acreage in this region. India and Pakistan have steadily controlled

the market by creating either surplus or constraining the supply of guar seed, which


11

fluctuates prices dramatically throughout the year. An example of the quick shifts in

price was seen in 2010, when refined guar gum prices surged from $5.25/kg ($2.38/lb) in

March 2012, and at the end of May 2012, the price was $24.25/kg ($11.00/lb) (AccuVal

Associates, 2012). This significant change in price within a few months severely limits

the continual use of guar gum. In the United States perhaps the only logical way

companies have to control the market is to offer contracts with regional producers and

processors through vertical integration. Once guar solves these issues and becomes a

more widely produced commodity, markets may buy and sell this commodity globally

through forward contracts.

Other Alternative Crops

Sesame (Sesamum indicum L.) is an oil crop that is mainly used in the food

industry for its high value oil along with other uses in paints and the pharmaceutical

industry (Oplinger, Putnam, et al., 1990). Sesame has been one of the most water

efficient crops grown for the High Plains only requiring 430 mm (17 in.) of precipitation

with hardly any supplemental irrigation (Extension, 2007).

Sesame has been gaining traction through companies like Sesaco, which helps

breed and market sesame lines for Texas through vertically integrated contracts. Sesame

was introduced to the United States in the 1930’s with around 1000 ha (2500 ac)

(Oplinger, Putnam, et al., 1990) grown to almost 8,000 ha (20,000 ac) (Delate, 2013)

today due to non-shattering varieties developed to aid in mechanical harvesting. The

current amount of production is still not enough to supply the demand, and 40,500 ha

(100,000 ac) needs to be grown domestically to satiate current demand (Delate, 2013).


12

Sesame has a great opportunity in the United States with a price of around $.95/kg

($.43/lb) (Smith, Yates, et al., 2014) and yields upwards of 1200 lbs. on dryland acreage

(Oplinger, Putnam, et al., 1990). Unlike guar, sesame does not have as many roadblocks

to become a mainstream crop, the most major problem that sesame faced was shattering

during mechanical harvest, but that has been fixed through new varieties released by

Sesaco. With water becoming scarcer, sesame as a dryland crop would be a sustainable

crop for the Texas High Plains.

Sorghum (Sorghum bicolor L.) is a great, drought tolerant alternative to water

intensive corn (Carter, Hicks, et al., 1989). Sorghum is used primarily in the livestock

and food industries. Sorghum is drought tolerant only requiring 500 mm (20 in) of water

over the entire growing season (Nebraska, 2014). With dryland yields of 2,017 kg/ha

(1,800 lbs./ac) and prices of $.072 per pound (Smith, Yates, et al., 2014), it can be a

profitable crop while using no supplemental irrigation. Several herbicides are available

for sorghum use, and there are not many prevalent diseases in sorghum today (Carter,

Hicks, et al., 1989). Once the mentality disappears that sorghum is an alternative to corn

in low price years, a larger market for sorghum will be formed and we will see acreage

increase on the Texas High Plains.


13

Chapter III

Materials and Methods

Field Study

In 2013 and 2014, two separate guar trials, 1) Advanced Breeding Trial, 2)

Experimental Breeding Lines Trial were grown at the Texas Tech Quaker Research Farm

located in northwest Lubbock, Texas. The research farm sets at an elevation of about 990

m (3250 ft.) and has a mix of Acuff fine sandy loam and Amarillo fine sandy loam soils.

The Advanced Breeding Trial had nine experimental lines with four commercial checks

replicated four times in 2013 and three times in 2014, while the Experimental Breeding

Lines Trial included 31 experimental lines and 5 commercial checks replicated twice both

years. Each trial was grown in a randomized complete block design, with 7.3 m (24 ft.)

plots and 1.8 m (6 ft.) clear alleys in between plots. The plots were planted June 13, 2013

and June 10, 2014 with a Hege single seedbed drill configured to double rows set 254

mm (10 in.) apart from each other. Plots were irrigated by a subsurface drip irrigation

system placed 200 mm (8 in.) below the surface and had emitters spaced 300.5 mm (12

in.) along each drip tape, while each drip tape had a lateral spacing of 1 m (40 in.). Both

years, the seedbed was pre-irrigated for optimal soil moisture and Trifluralin applied as

pre-plant incorporated (PPI). After planting, 67 kg/ha (60 lbs./ac) of 36-0-0 bulk liquid

nitrogen fertilizer was applied through fertigation in two separate 13.5 kg/ha (30 lbs./ac)

applications. Both crops were naturally terminated by the first freeze of the season.

Harvesting of the 2013 crop did not start until January 10, 2014 due to a late cotton

harvest, and the 2014 crop was harvested November 28, 2014 after 95% of the seed had

hardened. When the crop was harvested, 1 m (40 in.) was taken out of the middle of each


14

plot and threshed on a Kincaid thresher. After the seed was harvested out of the field,

they were cleaned on a Seedburo air seed cleaner. The total seed weight was taken after

the seed was cleaned, and then 100 seeds from each plot were counted and weighed.

Disease Rating

A disease rating scale needed to be created to measure disease on a scale from 1-

5. The scale needed to be firm enough for repeatability through multiple growing

seasons, but easy to explain. In 3.1, the created scale can be seen. When the plants were

rated, five different plants in each plot were measured and then the ratings were averaged

together to get a single plot score.

Forage Rating

In 2014, a forage matrix was added to the field study. On August 13, 64 DAP, 1

m (40 in.) was taken out of each plot, and the entire plant was placed in a bag and

weighed in field. The samples were then placed in the dehydrator room at the Texas

Tech Greenhouse, and 10 days later, the weight was taken again to find a dry weight of

the sample. The samples were then ground on a forage grinder, and the samples were

sent off to A&L Plains Lab for forage analysis.

All of the data for the field study was analyzed using JMP Pro 10 statistical

software.


15

Figure 2.1 Guar injury scale used to rate Alternaria leaf spot in plots at Texas Tech University Quaker Research Farm in 2013 and

2014. The triad on the left was rated a 1, which represents a completely dead leafset, while the triad on the far right was a 5, which is

a non-injured, fully photosynthesizing leafset.


16

Break-Even Price Analysis

The data for the economic part of this study was obtained from Texas A&M

Agrilife Research Extension budgets, which are updated each year for projecting the

return on each crop in future seasons (Smith, Yates, et al., 2014).

𝑃𝐶𝑇𝑌𝐶𝑇 − 𝐶𝐶𝑇 + 𝐶𝑖

𝑌𝑖= 𝑃𝑖

CT stands for cotton, while P, Y, and C stand for price, yield, and cost, respectively, and i

is a placeholder for any alternative crop that can be used to calculate a break-even price

against cotton. The formula derives the break-even price for each crop compared with a

two-bale cotton crop with changing yields for different scenarios while subtracting the

variable production costs of each crop. Three yield levels used for all crops was based on

an 80%, 100%, 120% of average yield found on the Agrilife budgets. This study focused

on differing yield levels instead of differing costs in producing those yields. The average,

estimated yield levels used for cotton lint, guar, sorghum, and sesame are 1120 kg/ha

(1000 lbs./ac.), 1120 kg/ha (1000 lbs./ac.), 6165 kg/ha (5500 lbs./ac.), and 1680 kg/ha

(1500 lbs./ac.), respectively. The variable costs for producing each crop were also

obtained from the Agrilife budgets. Holding all input costs constant gave a better

comparison of alternative crops’ break-even price compared to average cotton yields.

Pivot Profit Maximization

Using linear programming as the model, the optimal combination of crops has

been found based on a circle pivot field with the external dimensions of a 0.4 km x 0.4

km (.25 mile x .25 mile). These dimensions give the average field size for a High Plains

farm of 65 ha (160 ac.) and only 49 ha (120 ac.) are irrigated. Each corner adds 4 ha (10


17

ac.) of dryland crops, which are usually planted in a drought-tolerant cotton variety to

maximize profits. The following formula was the model’s basis for each of the

alternative crops explored.

𝜋 = 𝑃𝐶𝑇𝑌𝐶𝑇 + 𝑃𝐺𝑌𝐺 + 𝑃𝑆𝐺𝑌𝑆𝐺 + 𝑃𝑆𝑀𝑌𝑆𝑀 − 𝐶𝐶𝑇 − 𝐶𝐺 − 𝐶𝑆𝐺 − 𝐶𝑆𝑀

CT, G, SG, SM stand for cotton, guar, sorghum, and sesame, respectively; while P, Y, C

stand for price, yield, and cost, respectively. The assumption of the model is there can be

a higher profit using alternatives with cotton even with additional capital needed for

differing cultivation and harvest techniques. Many constraints were used to model this

profit maximization including: total land, irrigated acreage, labor, irrigation labor, limit

of total irrigation over the season from an average farm across the High Plains, limit of

dollar amount to just irrigation. With the decrease in overall irrigation to the proposed

753 mm/ha (1 ft./ac), cotton will have to be decreased to a smaller part of a circle to

optimize production costs and profitability. Each crop was calculated using the net profit

after direct and indirect expenses have been accounted into the profit per hectare. The

profit per hectare for each crop that produces medium yields using pivot irrigation and

dryland were compared as well as other constraints used based on each crop.


18

Chapter IV

Results and Discussion

Guar Field Study

Our hypothesis was that guar, sorghum, and sesame could all compliment the

current cotton crop on the Texas High Plains, but guar cannot prove sustainability until

there is a strong proven seed yield of over 1,120 kg/ha (1,000 lbs./ac), a larger seed (100

seed weight), and foliar disease resistance. The Advanced Breeding Trial has lines that

are closer to release than the Experimental Breeding Lines Trial. These lines have more

uniform seed yields and disease rating.

All of these lines had previously been selected prior to 2013, when Alternaria

infected the study. Lewis, which was released in 1986 by Texas Agricultural Station and

USDA-ARS(Undesander, Putnam, et al., 1991), fared very well in most traits across

years, but had a smaller seed (Table 4.1). The line TTUG-4-60-13 is one of the best

performing lines for all traits with a 4.7 average disease rating, and the largest seed size

of 3.6 grams/100 seed. The Texas Tech University line Monument did not do well in any

of the traits because of its extreme susceptibility to foliar disease, but it performed

slightly better in the Experimental Breeding Lines Trial (Table 4.2). The Monument

plots were almost fully defoliated before the frost due to the disease, and had reduced

yield and seed size. The main phenotypic difference between the two Texas Tech

University lines, Monument and Matador, is that Monument produces primarily a single

stem plant and Matador producers a bushy, multi-branched type of plant. Historically,


19

Monument has had larger seeds and better yields under higher plant populations, but

Matador has always had better disease resistance.

Forage yield and value of guar became an important index in 2014 because of the

production of high value forage. The crop could be swathed and baled for livestock feed

(Table 4.3). Once again, the experimental line TTUG-4-60-13 was a top performer in the

forage traits, Dry Yield, Acid Detergent Fiber (ADF), and Neutral Detergent Fiber

(NDF). However, Kinman, released in 1975 by Texas Agricultural Service, USDA-ARS,

and Oklahoma Agricultural Experiment Station (Undesander, Putnam, et al., 1991),

performed very well in the total nutrient % (Table 4.3) and historically is very disease

resistant.

In 2015, the trials will be expanded to six locations across New Mexico, Texas,

and Oklahoma to measure performance in disease rating, seed yield, and seed size to

support the eventual release top performing lines from the Advanced Breeding Trial.


20

Table 4.1 Advanced Breeding Trial that shows disease rating, seed yield, and seed size of nine experimental lines and four cultivars of guar (Cyamopsis

tetragonoloba L.) grown under drip irrigation at Lubbock, TX in the 2013 and 2014 growing seasons.

Disease Rating‡ Seed Yield Seed Size

Entry 2013 2014 Average 2013 2014 Average 2013 2014 Average

---------------------Rating-------------------- -----------------------kg ha-1----------------------- ----------------------g 100-1---------------------

Lewis 4.4 abc† 4.9 a† 4.7 a† 1370 a† 1249 ab† 1310 a† 2.9 ab† 3.1 ab† 3.0 bc†

Matador 4.5 ab 4.5 ab 4.5 a 1090 bcd 1351 a 1221 a 2.3 b 3.3 ab 2.8 c

TTUG-4-24-5 4.4 abc 4.1 ab 4.3 a 1276 ab 1047 abc 1162 ab 2.7 ab 3.2 ab 3.0 bc

TTUG-4-59-1 4.0 cd 4.4 ab 4.2 a 1402 a 741 bcd 1072 ab 2.6 ab 3.0 ab 2.8 c

TTUG-4-60-13 4.7 a 4.6 a 4.7 a 1008 bcd 1121 ab 1065 ab 3.6 a 3.5 a 3.6 a

TTUG-3-534-1 3.8 d 3.7 b 3.8 ab 1173 abc 925 abc 1049 ab 3.0 ab† 3.0 ab 3.0 bc

TTUG-4-26-7 3.8 d 4.3 ab 4.1 a 1235 ab 770 bcd 1003 ab 3.4 ab 3.8 a 3.6 a

TTUG-4-60-6 4.4 abc 4.1 ab 4.3 a 1199 ab 806 bcd 1003 ab 3.0 ab 2.8 ab 2.9 bc

TTUG-4-09-15 3.8 d 4.1 ab 4.0 a 844 de 900 bcd 872 ab 3.8 a 3.3 ab 3.6 a

Kinman 4.4 abc 4.8 ab 4.6 a 772 de 776 bcd 774 bc 3.0 ab 3.3 ab 3.2 ab

TTUG-4-34-4 4.0 cd 4.2 ab 4.1 a 739 e 784 bcd 762 bc 3.1 ab 3.2 ab 3.2 ab

TTUG-3-519-1 4.2 bcd 4.1 ab 4.2 a 873 cde 638 cd 756 bc 3.1 ab 2.9 ab 3.0 bc

Monument 1.0 e 4.0 ab 2.5 b 412 f 396 d 404 c 2.6 ab 2.6 b 2.6 c

† = Means within a column not followed by the same letter differ at the 0.05 level of probability by Student's t-test.

‡ = Disease Rating as 1.0 - Dead Plants; 2.0 - 80% Defoliation; 3.0 - 50% Defoliation; 4.0 - 20% Defoliation; 5.0 - No Symptoms.


21

Table 4.2 Experimental Breeding Lines Trial showing disease resistance rating, seed yield, and seed size

of 30 experimental breeding lines and six cultivars of guar (Cyamopsis tetragonoloba L.) grown under

drip irrigation at Lubbock, TX in the 2013 and 2014 growing seasons.

Disease Rating‡ Seed Yield Seed Size

Entry 2013 2014 2014 2014

-----------------Rating----------------- ------kg ha-1------ ------g 100-1------

TTUG-3-537-2 3.5 def† 3.3 abc† 1653 a† 3.9 ab†

TTUG-3-729-1 4.5 abc 2.4 efg 1629 a 3.2 bcd

TTUG-1401-79-3 4.7 ab 2.6 def 1617 a 3.8 ab

TTUG-1401-79-1 4.7 ab 3.0 bcd 1585 ab 3.3 bcd

TTUG-3-430-1 4.8 ab 2.6 def 1563 ab 3.0 cde

TTUG-3-824-2 3.7 cde 3.2 bcd 1559 ab 3.5 abc

TTUG-4-36-5 3.4 def 3.2 bcd 1519 ab 3.2 bcd

Matador 3.7 cde 1.8 efg 1509 abc 3.0 cde

TTUG-3-914-2 4.0 bcd 2.6 def 1508 abc 3.6 abc

TTUG-3-524-1 4.3 bcd 2.6 def 1490 abc 3.2 bcd

TTUG-4-24-4 3.7 cde 2.9 cde 1466 bcd 3.1 cde

TTUG-3-830-2 3.3 def 1.7 efg 1460 bcd 3.8 ab

TTUG-3-823-2 3.5 def 2.1 efg 1436 bcd 4.0 a

TTUG-3-626-1 4.2 bcd 3.6 ab 1430 bcd 3.5 abc

TTUG-1401-9-1 4.6 abc 2.5 def 1410 cde 4.0 a

TTUG-4-43-4 4.5 abc 2.7 def 1351 def 2.9 cde

TTUG-3-821-4 3.9 cde 1.3 efg 1342 def 3.1 cde

TTUG-4-53-4 2.8 fg 2.8 def 1316 efg 3.2 bcd

TTUG-4-32-8 5.0 a 2.5 def 1307 efg 3.4 bcd

TTUG-4-36-8 3.6 def 1.0 g 1252 fgh 2.7 de

TTUG-4-22-4 2.8 fg 1.0 g 1247 fgh 3.1 cde

TTUG-3-626-2 4.5 abc 2.9 cde 1193 fgh 3.1 cde

TTUG-3-911-1 3.7 cde 4.0 a 1181 ghi 3.6 abc

HES 1123 3.1 efg 1.6 efg 1171 ghi 2.5 de

TTUG-3-919-3 3.8 cde 1.2 efg 1167 ghi 3.0 cde

TTUG-3-323-1 3.1 efg 2.1 efg 1118 hij 3.6 abc

Lewis 3.3 def 1.0 g 1106 hij 3.0 cde

TTUG-3-518-2 4.1 bcd 2.0 efg 1049 hij 3.3 bcd

Kinman 2.5 fgh 1.0 g 965 ijk 3.4 bcd

TTUG-4-60-13 4.8 ab 3.0 bcd 947 ijk 3.1 cde

TTUG-4-09-2 2.7 fg 1.0 g 930 ijk 3.1 cde

Santa Cruz - 1.0 g 874 jkl 2.9 de

TTUG-3-217-1 3.4 def 1.0 g 766 jkl 2.9 cde

Monument 1.6 h 1.0 g 642 kl 2.1 e

TTUG-4-60-9 2.8 fg 1.1 fg 628 kl 2.6 de

TTUG-4-09-11 3.3 def 1.2 efg 400 l 2.5 de

† = Means within a column not followed by the same letter differ at the 0.05 level of probability by

Student's t-test.

‡ = Disease Rating as 1.0 - Dead Plants; 2.0 - 80% Defoliation; 3.0 - 50% Defoliation; 4.0 - 20%

Defoliation; 5.0 - No Symptoms.


22

Table 4.3 Dry forage yield, crude protein, ADF, and NDF of nine experimental lines and four cultivars of guar (Cyamopsis

tetragonoloba L.) grown under drip irrigation at Lubbock, TX in the 2014 growing season.

Entry Dry Yield Crude Protein ADF NDF Total Nutrients

------kg ha-1------ ---------%--------- ---------%--------- ---------%--------- ---------%---------

Kinman 4631 a† 18.6 e† 21.4 b† 28.7 ab† 66.3 a†

TTUG-4-34-4 4442 a 21.1 abc 23.7 ab 29.8 ab 64.6 ab

TTUG-4-60-13 4347 a 19.8 cde 26.3 a 32.4 a 62.6 b

TTUG-4-26-7 4347 ab 20.6 bcd 24.7 ab 29.9 ab 63.8 ab

TTUG-3-534-1 4253 ab 20.3 bcd 21.4 b 29.2 ab 66.3 a

TTUG-4-60-6 4252 ab 21.2 abc 24.0 ab 27.2 b 64.3 ab

TTUG-4-24-5 4158 ab 19.5 cde 20.1 b 30.4 a 67.3 a

Matador 4040 ab 19.7 cde 22.2 ab 28.1 b 65.7 ab

TTUG-4-59-1 3969 ab 19.7 cde 25.9 ab 32.6 a 62.9 ab

Lewis 3780 ab 20.8 bcd 21.4 b 27.3 b 66.3 a

TTUG-4-09-15 3686 ab 22.0 ab 23.2 ab 29.9 ab 65.0 ab

TTUG-3-519-1 3591 ab 22.1 a 23.0 ab 29.0 ab 65.1 ab

Monument 3213 b 18.6 de 26.9 a 31.7 a 62.1 b

† = Means within a column not followed by the same letter differ at the 0.05 level of probability by Student's t-test.


23

Economic Analysis

Break-Even Price Analysis

The returns for the crops were used in calculating the break-even price (Table

4.4). All three alternative crops show a change in the price levels to break-even with

cotton, but one particularly stands out. Sesame showed a higher profit level than average

cotton profit for a producer, resulting in a decrease of the actual market price for the

break-even price (Table 4.4). After calculating the differing break-even prices for each

yield level, the final break-even prices of each crop was calculated (Table 4.5).


24

Table 4.4. The current prices, estimated gross income per acre,

variable costs, and net income of four crops adapted to the Texas

High Plains.

Returns for Four Selected Crops

Index Cotton Guar Sorghum Sesame

---------------------------$ kg-1--------------------------

Current Price 1.68 0.77 0.19 1.21

---------------------------$ ha-1--------------------------

Income 2852 965 1142 2039

Variable Costs -1882 -610 -865 -810

Total Return 970 254 277 1229

Table 4.5. The calculated break-even prices found for each of the

selected crops based on an average yield and +/- 20% yield change.

Break-Even Prices for Four Selected Crops

Yield Cotton Guar Sorghum Sesame

---------------------------$ kg-1--------------------------

-20% 2.09 1.76 0.37 1.32

Average 1.68 1.41 0.31 1.06

+20% 1.39 1.17 0.24 0.88


25

Pivot Profit Maximization

The model was evaluated repeatedly, using different parameters as limiting

factors. The following six scenarios of a .64 km2 circle pivot are shown below and

represented by bar graphs: 1) A producer with unlimited resources except for land

constraints (Figure 4.1), 2) low water availability and low amount of labor (Figure 4.2),

3) high water availability and low amount of labor (Figure 4.3), 4) low maximum

irrigation costs and high amount of labor (Figure 4.4), 5) low maximum irrigation costs

and low amount of labor (Figure 4.5), and 6) finally a medium cost with medium amount

of labor and water availability (Figure 4.6). All of the following scenarios are within a

25% increase or decrease in the medium amount of available constraints. For example,

low water availability would be 25% less than an average amount of about 10,261 mm-ha

(1,000 ac-in.) available over the entire year or about 7,696 mm-ha (750 ac-in).

The producer in Figure 4.1 has optimized his operation with only irrigated land

limiting his profit. If this scenario plays out, his maximized net profit will be $62,512

using strictly irrigated cotton inside the pivot and guar in the corners. This is taking into

account a 1,681 kg/ha (1,500 lb/acre) cotton yield at $1.68/kg ($0.76/lb) and a (318 kg)

700 lb yield at $1/kg ($0.45/lb) for the guar.

The producer in Figure 4.2 has optimized his operation with a low irrigation

availability such as that found in the Southern High Plains. The only limiting factor in

this scenario is the amount of irrigation available to him from the aquifer itself and not

imposed through regulation. His overall profit has dropped substantially to just under

$37,000. Considering the irrigated sesame is much more water efficient and is only


26

$140/ha ($56.71/acre) lower than irrigated cotton, then this scenario seems extremely

plausible for a producer on the High Plains that does not have the same amount of water

available as in past growing seasons. If he could find 10 mm-ha (1 acre-inch) more over

the season, he could increase his profit by roughly $22.

Figure 4.3 shows a different scenario for a producer with high water availability

but a low amount of labor. The overall profit has increased to about $41,500 due to

higher supplemental irrigation, but the only limiting factor is the lower amount of labor

that he can use. If he could find one more employee to help him on the farm, his profits

could increase by $360.

Figure 4.4 depicts a producer that wants to keep his irrigation costs at a minimum

but has a high amount of labor that he can use. His optimized profit would be almost

$42,200, and his only constraint would be the amount of money he wants to pay for

irrigation. If he added one more dollar to irrigation costs, his overall profit would

increase by almost $2.50.

Figure 4.5 shows a very interesting and plausible situation found with many

farmers on the High Plains. A grower wants to reduce costs that he deems unnecessary

such as irrigation costs and extra labor. His overall profit is around $37,000, but if he

increased labor by one hour, he would increase profits by $202. If he only increased

irrigation costs by $1, his profit would increase by $0.78.

Finally the last scenario is the average scenario for most farmers across the West

Texas and the High Plains, a “middle-of-the-road” take on the situation with average

constraints on everything: labor, water, costs, etc. Figure 4.6 shows the average


27

producer, and how it would play out in this situation. He could use very little water at all,

and focus all the irrigation on 12 ha (30 ac.) of cotton production that could yield

upwards of 4-5 bale cotton 2,240-2,800 kg/ha (2000-2500 lb/ac). The rest of the 53 ha

(130 ac.) could be planted in dryland guar and bring about a profit of just under $33,500.

The only constraint that he has would be more land, and if he has multiple crop circles,

this could be a viable option. If he added one more acre of land, then his profits would

increase by $132.50.


29

(49)

0 0 0 0

(16)

0 00

10

20

30

40

50

60H

ecta

res

Figure 4.1 Area allocation of 65 ha (160 ac) to eight cropping choices on fields with unlimited water and labor.


30

0 0

(20)

0 0

(45)

0 00

5

10

15

20

25

30

35

40

45

50

Hec

tare

s

Figure 4.2 Area allocation of 65 ha (160 ac) to eight cropping choices on fields with low water and average labor.


31

(23)

0 0 0 0

(42)

0 00

5

10

15

20

25

30

35

40

45

Hec

tare

s

Figure 4.3 Area allocation of 65 ha (160 ac) to eight cropping choices on fields with high water and low labor.


32

0 0

(28)

0 0

(37)

0 00

5

10

15

20

25

30

35

40H

ecta

res

Figure 4.4 Area allocation of 65 ha (160 ac) to eight cropping choices on fields with low irrigation costs and high labor.


33

(9)

0

(14)

0 0

(42)

0 00

5

10

15

20

25

30

35

40

45

Hec

tare

s

Figure 4.5 Area allocation of 65 ha (160 ac) to eight cropping choices on fields with low irrigation costs and low labor.


34

(12)

0 0 0 0

(53)

0 00

10

20

30

40

50

60H

ecta

res

Figure 4.6 Area allocation of 65 ha (160 ac) to eight cropping choices on fields for an Average High Plains Producer with average water

availability, average irrigation costs and average labor.


35

Chapter V

Conclusions

The primary objective of this study was to identify sustainable, water-efficient

alternative crops for the Texas High Plains through phenotypic evaluation of the guar in

field studies and two separate economic analyses. The economic analyses were needed to

calculate the break-even prices for potential, alternative crops to compete with two-bale

cotton, under six different management strategies to increase profit on center pivots by

growing water-saving crops to allow focus on cotton. The application of this type of

study can be used to evaluate any alternative crop anywhere in the world.

As we look towards the future, many producers will need to look into new,

alternative crops that will maximize their profits while minimizing irrigation use. The

Texas High Plains is a thriving region and in 2010 there were almost one million people

living in the 54 counties that it represents (U.S. Census Bureau, 2010). There will be

more people moving towards the High Plains with the rise in oil and gas production,

meaning that there will be a more urban water need in the coming years. If we want to

continue to thrive, producers will need to continue to look at new technology such as

Variable Rate Irrigation and Subsurface Drip Irrigation to maximize irrigation efficiency

while maximizing yields with less irrigation available. Guar and sesame are vertically

integrated industries, so it might be difficult for new producers to enter into the market

and find viable contracts; meaning that cotton will continue to be the staple crop grown

on the High Plains as long as there is sufficient water. Producers can integrate these


36

alternative crops into their current crop rotation and enjoy benefits of higher yields using

an appropriate rotation.


37

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http://lubbock.tamu.edu/files/2011/10/guarnodulation_4.pdf.

http://www.hort.purdue.edu/newcrop/afcm/guar.html.

agronomic and economic analysis of guar (cyamopsis

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