Reduced Cotton Yield Research Articles

Goosegrass (Eleusine indica) density effects on cotton (Gossypium hirsutum)

Goosegrass is one of the worst agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. Field experiments were conducted during 2010–2012 to determine the influence of goosegrass density on cotton growth at the weed densities of 0, 0.125, 0.25, 0.5, 1, 2, and 4 plants m−1 of row. Seed cotton yield tended to decrease with the increase in weed density, and goosegrass at a density of 4 plants m−1 of row significantly reduced cotton yields by 20 to 27%. A density of 11.6–19.2 goosegrass plant m−1 of row would result in a 50% cotton yield loss from the maximum yield according to the hyperbolic decay regression model. Boll production was not affected in the early growing season. But boll numbers per plant were reduced about 25% at the density of 4 plants m−1 of row in the late growing season. Both cotton boll weight and seed numbers per boll were significantly reduced (8%) at 4 goosegrass plants m−1 of row. Cotton plant height, stem diameter and sympodial branch number were not affected as much as cotton yields by goosegrass competition. Seed index, lint percentage and lint fiber properties were unaffected by weed competition. Intraspecific competition resulted in density-dependent effects on weed biomass per plant, 142–387 g dry weight by harvest. Goosegrass biomass m−2 tended to increase with increasing weed density as indicated by a quadratic response. The adverse impact of goosegrass on cotton yield identified in this study has indicated the need of effective goosegrass management.

Impacts of climate change on cotton yield in China from 1961 to 2010 based on provincial data

To develop scientific countermeasures, the impacts of climate change on cotton yield during 1961–2010 in three major cotton-producing regions of China were studied by using the available provincial data. The results indicate that (1) a rise in average temperature increased the cotton yield in most provinces of Northwest China and the Yellow River valley; however, the rise in average temperature decreased the cotton yield in the Yangtze River valley. Moreover, cotton production across the entire study region was reduced by approximately 0.1% relative to the average during 1961–2010. (2) A decrease in diurnal temperature range (DTR) reduced cotton yield in some provinces, while a beneficial DTR effect was observed in the other provinces. Changes in DTR resulted in an average decrease in production by approximatly 5.5% across the entire study region. (3) A change in the amount of precipitation increased the cotton yield in some provinces; however, it caused a decrease in other provinces. The decrease in average production due to the change in precipitation was approximately 1.1%. We concluded that the changes in temperature and precipitation decreased cotton yields in China, while beneficial effects of temperature and precipitation existed in the cotton-growing regions of Northwest China during 1961–2010.

Effect of 1-MCP on Cotton Plants under Abiotic Stress Caused by Ethephon

Many environmental stress factors have been identified to increase square and boll abscission and thus result in reduced cotton yield. Under stress conditions, ethylene is elicited. Ethylene peaks before abscission to promote the formation of the abscission layer and plays a major role in early season square and boll abortion in cotton (Gossypium hirsutum L.). In addition, ethylene stimulates the leaf senescence process. Thus, it is desirable to protect plants from ethylene-induced fruit loss and premature leaf senescence under stress conditions. The objective of this study was to evaluate the ability of 1-methylcyclopropene (1-MCP) to protect cotton plants against abiotic stress caused by ethephon (ethylene promoting effect). Field studies using a randomized complete block design with four replications were conducted in 2010 and 2011 at Texas A&M AgriLIFE Research Farm in Burleson County, TX. Eight treatments that consisted of two 1-MCP rates (0 and 10 g a.i. ha-1) in combination with four ethephon rates (0, 146, 292, 438 mL&middotha-1) were imposed at the first flower (FF) stage of the development. 1-MCP increased plant height and number of main stem nodes in both years. In addition, 1-MCP-treated plants exhibited greater membrane integrity and increased photosystem II quantum efficiency and thus delayed senescence in both years. These potentials for yield increase were realized in 2011 with 1-MCP treatment exhibiting a higher lint yield. In 2012, although 1-MCP treatment increased number of open fruit and open fruit weight per plant significantly, no significant lint yield increase was detected.

Seletividade de clomazone isolado ou em mistura para a cultura do algodoeiro

O clomazone destaca-se como um dos principais herbicidas utilizados em pré-emergência na cultura do algodoeiro, mesmo levando-se em conta o fato de que muito pouco se sabe em relação à sua seletividade para a cultura. Objetivou-se com este trabalho avaliar a seletividade do clomazone isolado ou em mistura com outros herbicidas utilizados em pré-emergência na cultura do algodoeiro. O delineamento experimental foi o de blocos ao acaso, com quatro repetições, com a utilização de testemunhas duplas. Foram avaliados 13 tratamentos, os quais foram constituídos de clomazone isolado ou combinado com os herbicidas S-metolachlor, diuron, prometryne, alachlor, oxyfluorfen e trifluralin. Foram avaliados porcentagem de fitointoxicação, estande final, altura de plantas, número de maçãs e rendimento final de algodão em caroço. O clomazone, isolado nas doses de 1,00 e 1,25 kg ha-1 ou em associação com S-metolachlor (0,76 kg ha-1), diuron (1,50 kg ha-1), prometryne (1,50 kg ha-1), alachlor (1,44 kg ha-1) e trifluralin (1,80 kg ha-1), foi seletivo à cultura do algodão cv. Nu Opal. Em contrapartida, sua associação com oxyfluorfen (1,25 + 0,19 kg ha-1), trifluralin + diuron (1,25 + 1,80 + 1,50 kg ha-1) e trifluralin + prometryne (1,25 + 1,80 + 1,50 kg ha-1) proporcionou redução na produtividade do algodoeiro.

Response of Upland Cotton (Gossypium hirsutum) to Fruiting Branch Removal

Cotton response to fruiting branch removal (FBR) is critical information in estimating plant recovery potential and making management decisions after hail storms or other physical damages. Fruiting branches were removed at first bloom (R8), 2.5-cm boll (R12) and peak bloom (R16) growth stages. Five FBR treatments were conducted at each of the above three growth stages: 0 %, 25 %, 50 %, 75 % and 100 %. At harvest, five plants were randomly chosen from each plot and branches separated into three groups: vegetative, lower and upper fruiting branches. Lower fruiting branches were from the nodes where FBR treatments were conducted, whereas upper fruiting branches were the new branches developed after FBR. Seed cotton weight, open boll number and node number in each group were recorded. Fruiting branch removal increased boll number, boll size and boll/node on the upper fruiting branches, which compensated yield loss on lower fruiting branches. Generally, FBR at the first bloom reduced cotton yield more than it did at the 2.5-cm boll and peak bloom growth stages when FBR percentage was lower than 75 %. The removal of all 16 fruiting branches at peak bloom reduced cotton yield by 16.8 %, indicating remarkable compensation ability by cotton plants in climates with a long growing season.

Investigation of the Effects of Soil Compaction in Cotton

Soil compaction can cause yield reductions in cotton (Gossypium hirsutum). This study investigated the effect of soil compaction on canopy spectral reflectance, soil electrical conductivity (EC), and cotton yield. Field experiments were conducted during 2003-2005 using a completely randomized block design with four soil compaction treatments. The treatments were no subsoiling (control); subsoiled, disked, and bedded (conventional); subsoiled and compacted (compaction I); and compacted with no subsoiling (compaction II). Field data were collected on soil resistance, canopy reflectance, soil EC, and cotton yield. Comparison of means showed differences between treatments in reflectance in 2003 and 2004, soil compaction parameters in 2004 and 2005, and soil EC and yield in 2005. The depth and thickness of the hardpan were significantly correlated to green NDVI on 16 September (R2 = 0.53) in 2003. Depth, average resistance of hard pan, and EC all showed relationships with yield in 2005. Their combination as independent variables could explain 65% of the variability in cotton yield in 2005. These results verified that compaction affected canopy reflectance and reduced cotton yield in Arkansas. The practical implications of the outcome of this study are the potential use of EC and canopy reflectance to infer crop yield and extent of soil compaction. However, a multi-site and multi-year study is necessary to confirm this possibility.

MAPPING PHYMATOTRICHUM ROOT ROT OF COTTON USING AIRBORNE THREE-BAND DIGITAL IMAGERY

Phymatotrichum root rot, caused by the fungus Phymatotrichum omnivorum, is a serious and destructive diseasethat significantly reduces cotton yield and lowers lint quality. Cultural practices are commonly recommended for the controlof cotton root rot, and fungicides and fumigants that may suppress the disease have also been used. Because of the high costsof these chemicals, their use may be economically feasible only when the infested portions of the field are treated. Theobjective of this study was to evaluate airborne multispectral imagery for detecting and mapping root rot areas in cotton fieldsfor site-specific management of the disease. One center-pivot irrigated field and one rainfed field near Corpus Christi, Texas,were selected for this study. Airborne three-band digital imagery was taken from the two fields shortly before harvest in 2001when the infested areas with wilted and dead plants were almost fully pronounced for the season. The imagery wasgeoreferenced and then classified into healthy and root rot areas using unsupervised classification. Accuracy assessment onthe classification maps for the two fields indicated that airborne imagery effectively and accurately identified root rot areaswithin the fields. Ground samples taken from the fields showed that cotton yield and some lint quality indices were significantlylower in root rot areas than in healthy areas. Buffer zones around the root rot areas were generated to account for the spreadof cotton root rot on the classification maps. The mapping procedures and maps presented in this study will be useful forsite-specific management of the disease.

Diurnal pattern of aphid feeding and its effect on cotton leaf physiology

Cotton aphid ( Aphis gossypii G.) populations seemed to fluctuate over the past years in cotton ( Gossypium hirsutum L.) perhaps as a result of excessive use of insecticides for controlling more problematic pests. Contradictory plant responses have been observed depending upon the aphid/plant system, and it is unclear if cotton aphids, abiotic stress or both are responsible for cotton yield reduction in aphid-infested fields. Our objectives were to investigate the diurnal changes in the physiology of cotton leaves following aphid herbivory, and the diurnal pattern of aphid feeding. The experiment was conducted in a growth chamber using the cotton cultivar ‘Stoneville 474’. Leaves of the same age and size were infested with wingless adults plus nymphs. Cotton aphids were allowed to increase in numbers without restriction for 9 days, after which the amounts of carbohydrates in aphid-honeydew, and the number of honeydew droplets excreted per aphid were measured. Photosynthetic rates, dark respiration rates and foliar non-structural carbohydrates were measured. The amount of individual carbohydrates found in the honeydew was significantly different with time. The total amount of carbohydrates excreted per aphid within a 24-h period averaged 2.5 μg. The number of honeydew droplets excreted per aphid varied significantly from time to time period. Cotton aphids did not significantly alter photosynthesis or respiration rates or non-structural carbohydrates on leaves. Aphid populations of approximately 300 per leaf on the 9th day of infestation did not appear to significantly alter the physiology of cotton leaves.

Bromoxynil Antagonizes Johnsongrass (Sorghum halepense) Control with Graminicides

Field studies were conducted over 2 yr to evaluate rhizome johnsongrass control with tank mixtures and sequential applications of bromoxynil at 1.7 kg ai/ha and the graminicides clethodim, fluazifop-P, and quizalofop-P. When compared with the graminicide alone, bromoxynil reduced johnsongrass control 28 days after treatment (DAT) 20, 36, and 55% when applied in combination with clethodim, fluazifop-P, and quizalofop-P, respectively. Application of bromoxynil 7, 3, and 1 d before or 1, 3, and 7 d after all graminicides reduced antagonism when compared with the bromoxynil plus graminicide mixtures. Based on johnsongrass control 28 DAT, antagonism was precluded when bromoxynil was applied 3 d before clethodim and 7 d before fluazifop-P and quizalofop-P. Application of bromoxynil 3 and 7 d after quizalofop-P and 7 d after clethodim also precluded antagonism. The antagonistic tank mixtures of bromoxynil and graminicides reduced cotton yield 17% because of reduced johnsongrass control compared with graminicides alone. A 3-d or greater application interval between bromoxynil and the graminicides was necessary to maximize cotton yield.

Spotted Spurge (Euphorbia maculata) Interference with Cotton (Gossypium hirsutum)

Field studies were conducted from 1988 through 1990 in Fayetteville, AR, to measure competitiveness of spotted spurge in cotton. Population levels were established by transplanting seedlings from other field areas. There was a positive linear relationship between cotton boll numbers and seed cotton yield. Percent reduction in cotton height, leaf area, dry weight, boll numbers, and seed cotton yield increased as spotted spurge densities increased. Seed cotton yield reduction was 47, 57, and 85% for spotted spurge densities of 5, 10, and 50 spotted spurge plants m–1of row.

Purple Nutsedge (Cyperus rotundus) Control in Reduced-Tillage Cotton (Gossypium hirsutumL.) with Low-Volume Technology

Field experiments conducted over three years at Stoneville, MS evaluated invert emulsion and oil diluents on the efficiacy of glyphosate and MSMA on purple nutsedge. The herbicides were applied at 0.6 and 1.1 kg ai/ha in an invert emulsion (oil-in-water) and a paraffinic oil at 19 L/ha (low-volume) and in water with a non-ionic surfactant (0.25% v/v) at 187 L/ha (high-volume). Purple nutsedge control with both herbicides was greater with the low-volume, invert emulsion and oil diluent applications than with high-volume, water diluent applications. Glyphosate and MSMA at 1.1 kg/ha in the oil diluent controlled purple nutsedge at least 88% when compared with the invert emulsion (≥ 75 and ≥ 76%, respectively) and water (≥ 42 and ≥ 44%, respectively) diluents. Cotton injury and seed cotton yields were unaffected by any treatment with MSMA but glyphosate with each diluent caused unacceptable cotton injury and seed cotton yield reduction.

Insecticides Modify Cotton (Gossypium hirsutum) Response to Clomazone

Field experiments were conducted to determine if aldicarb, disulfoton, or phorate applied in-furrow at 0.84 or 1.12 kg ai ha–1affected cotton response to clomazone applied PPI or PRE at rates ranging from 0 to 1.12 kg ai ha–1. Disulfoton and phorate greatly reduced clomazone-induced chlorosis, stunting, and death of cotton seedlings. Compared with no insecticide or with dimethoate applied POST, aldicarb did not affect cotton response to clomazone. A clomazone rate by insecticide interaction was not observed for cotton yield. Clomazone reduced cotton yield at one of five locations. Insecticides affected yield at three locations, where highest yields were from cotton treated with aldicarb. In a separate experiment with 0.56, 1.12, and 2.24 kg ha–1of phorate applied in-furrow and 1.12 kg ha–1of clomazone applied PPI, phorate at all rates protected cotton from clomazone phytotoxicity.

Growth and Interaction of Barnyardgrass (Echinochloa crus-galli) with Cotton (Gossypium hirsutum)

Several weed-free and barnyardgrass competition periods were established and maintained in cotton in field plots to evaluate their influence on cotton yield and seed production of barnyardgrass. When barnyardgrass was sprayed with fluazifop 3, 6, 9, or 12 weeks after cotton emergence, only plots sprayed at 3 weeks yielded as much cotton as plots kept weed free. Barnyardgrass permitted to compete for 6, 9, 12, and 25 weeks reduced cotton yields an average of 21, 59, 90, and 97%, respectively. When barnyardgrass was seeded into weed-free plots at 3, 6, 9, and 12 weeks after cotton emergence, a weed-free period of 9 weeks was required to prevent significant cotton yield reduction. Cotton in plots weed free for 3 and 6 weeks yielded an average of 13 and 87% as much seed cotton, respectively, as weed-free controls. Barnyardgrass produced 15 to 85% as many seeds as weedy check plots in plots weed free for less than 9 weeks and in plots where control was delayed for 9 and 12 weeks. Cotton grades were reduced because of grass in plots weed free for 3 and 6 weeks, and in plots where barnyardgrass competed for 9 and 12 weeks.

Interference of Selected Weeds in Cotton (Gossypium hirsutum)

In 1987 and 1988, effects of full-season interference of individual weeds on cotton yield were measured with area of influence procedures. In 1987, one spurred anoda, common cocklebur, large crabgrass, jimsonweed, common lambsquarters, redroot pigweed, common ragweed, or prickly sida plant per 3 m of row reduced cotton yield between 1% and 7%. Sicklepod did not cause a detectable yield loss. Redroot pigweed, common cocklebur and common ragweed caused 7%, 6% and 5% yield loss, respectively, in 1987. In row weed influence varied from 17 cm (large crabgrass interference) to 86 cm (common cocklebur interference). In 1988, yield losses by individual weeds ranged from 3% to 27%. Common cocklebur, jimsonweed, and common ragweed reduced cotton yields 28%, 15% and 12%, respectively. Spurred anoda and common cocklebur influenced 160 cm and 136 cm of cotton row, respectively. Sicklepod influenced only 47 cm of cotton row.

Analysis of the effects of herbicides on cotton yield trends

Cotton ( Gossypium hirsutum L.) yields have declined since 1965 despite improvements in technology and introductions of higher yielding cultivars. Cotton scientists have been unable to identify exact causes of the yield reduction. As part of the effort to examine possible causes for the yield reduction problem, the cotton crop simulation model, GOSSYM, was used to analyze the effects of root damage caused by herbicides on cotton yield trends. Weather, soil and cultural input data taken at five locations for over 20 years were acquired for this study. Simulations were completed for crops grown at the cotton breeder's variety trial locations at Florence, SC; Stoneville, MS; College Station, TX; Phoenix, AZ; and Fresno, CA. The simulated adverse effects of the herbicides on cotton yields varied from location to location due to their interactions with soil, plant and atmospheric variables. Cooler temperatures in Stoneville, MS, intensified herbicide damage, while the long growing season and warm climate in Fresno, CA, reduced the adverse effects of herbicide damage. Increased N and water shortages were apparent with herbicide induced root pruning. The effect of the herbicides on simulated cotton yield reduction was highest at Stoneville, MS, showing a decrease of 137 kg ha −1. The lowest yield reductions (14 kg ha −1) were observed at Fresno, CA, due to herbicidal action on cotton roots. The effect of herbicides on cotton yield reduction was found to be greater under unfavorable weather conditions like cooler temperatures during the boll-opening period.

Growth and Interaction of Johnsongrass (Sorghum halepense) with Cotton (Gossypium hirsutum)

Several weed-free and johnsongrass competition periods were established and maintained in cotton to evaluate their influence on cotton yield and reproduction of johnsongrass. When johnsongrass was sprayed with fluazifop in field plots 3, 6, 9, or 12 weeks after cotton emergence, only plots sprayed at 3 weeks yielded as much cotton as weed-free plots. Johnsongrass permitted to compete for 6, 9, 12, and 25 weeks reduced cotton yields 20, 60, 80, and 90%, respectively. When johnsongrass was transplanted into weed-free plots 3, 6, 9, and 12 weeks after cotton emergence, a weed-free period of 9 weeks was required to prevent significant cotton yield reduction. Cotton in plots weed free for 3 and 6 weeks yielded 81 and 89% as much seed cotton, respectively, as weed-free controls. Johnsongrass competing with cotton for 9 to 12 weeks produced 20 and 40% as many seeds and rhizomes, respectively, as weedy control plots. Some seeds and rhizomes were produced (1% of weedy check plots) in plots weed free for 9 to 12 weeks. Cotton grades were reduced in plots weed free for 3 and 6 weeks, and in plots where johnsongrass competed for 9 to 25 weeks.

Seasonal and Soil Fertility Effects on the Response of Waterlogged Cotton to Foliar‐Applied Nitrogen Fertilizer

AbstractThe majority of irrigated cotton (Gossypium hirsutum L.) soils in Australia are poorly drained, and the short‐term waterlogging associated with extended furrow irrigation reduces cotton yield, partly by reducing the uptake of N. Foliar application of N before irrigation can overcome a transient shortage, but yield responses have been variable. Seasonal and soil N fertility effects on the response of waterlogged cotton to foliar‐applied N fertilizer were studied over three seasons at Narrabri, N.S.W., Australia. A cracking grey clay soil (Typic Pellustert) was waterlogged by furrow irrigations lasting 4 to 32 h. Climatic and soil fertilizer conditions included a cool, moist season with optimal soil fertilizer N; a hot, arid season with high soil fertilizer N; and a hot, arid season with a wide range of soil fertilizer N. Foliar N was applied at 0, 5, 10, and 20 kg ha−1 in the first season, 0, 15, 30, and 60 kg ha−1 in the second season, and 0, 60, 120, and 180 kg ha−1 in the third season. Increased waterlogging reduced N uptake and lint yield. Nevertheless, there was no response to foliar N in the cool, moist season because factors other than N limited growth and yield whether or not N was supplied to the foliage. Lack of response to foliar N in the hot, arid season with high soil N fertility was attributed to high uptake of N (163 kg N ha−1) by untreated shoots, which compensated for reduced uptake by the roots during waterlogging. A three‐factor interaction in the third season confirmed that more cotton yield was recovered by applying foliar N under more severe waterlogging when soil N levels were not high. At N rates of 120 and 180 kg ha−1, shoots recovered more soil‐applied N than foliar‐applied N. Recoveries were similar at 60 kg N ha−1. The results confirmed that foliar N can ameliorate the effects of waterlogging in cotton, defined some of the conditions under which responses to foliar N occur, and explained some of the variability in response to foliar N found under commercial conditions.

Interference of Hemp Sesbania (Sesbania exaltata) with Cotton (Gossypium hirsutum)

Full-season interference effects of hemp sesbania [Sesbania exaltata(Raf.) Cory. # SEBEX] on cotton (Gossypium hirsutumL. 'Stoneville 213′) were investigated on a fine sandy loam soil for 3 yr at Stoneville, MS. Experimentally induced hemp sesbania populations of ≥ 3223 plants/ha significantly reduced cotton yields. Interference of hemp sesbania at 3223, 6456, 16 114, and 32 228 plants/ha, equivalent to 1, 2, 5, and 10 plants/3.3 m, reduced seed cotton yields by 19, 25, 45, and 53%, respectively. Cotton boll weights were reduced by 9% when hemp sesbania infestations were ≥ 16 114 plants/ha. Cotton plant density, seedling vigor, and initial cotton white blooms/ha at ≤75 days after planting (DAP) did not differ with varying densities of hemp sesbania. Cotton white blooms/ha were reduced by 32 228 hemp sesbania plants/ha by 77 DAP and by all weed densities by 98 DAP. Hemp sesbania height was equal to or greater than cotton height by 55 to 65 DAP. Light penetration at 1 m above the top of the cotton canopy was 36% less than in weed-free plots when hemp sesbania densities were ≤6446 plants/ha. Likewise, light penetration was reduced at the cotton canopy top and at midcanopy but was not less at the soil surface unless hemp sesbania densities were ≤ 32 223 plants/ha.

Residual Compaction Effects on Cotton Stand and Yields

ABSTRACT SOIL compaction is known to affect crop yields. In the work reported here the residual effects of soil compaction on cotton yield reduction through diminished plant stand and increased stand variability have been established. A simple variational model is used to predict average yield from the mean values land the standard deviations of the crop stand and water use in the field. Good agreement was attained between predicted and measured average yields of seed cotton for trickle and sprinkler irrigated fields. Seed cotton yields were found to be more sensitive to stand variations than to variations in water distributions under the described experimental conditions.

Management of Blank Rows in Dryland Skip-Row Cotton

ABSTRACT DRYLAND skip-row cotton yields were increased 66 to 79 percent by applying cotton gin trash to the blank rows in a plant-two-skip-two row system. Sorghum planted 15 June to protect the blank rows from wind ero-sion reduced cotton yields 22 to 38 percent. A 15 July planting of sorghum did not reduce cotton yields but did not always produce enough cover to protect the blanks from wind erosion. Millet planted 15 July usually pro-duced enough cover to protect the soil and did not reduce cotton yields 4 out of 8 years.