• Authors:
    • Barnes, E.
    • Scharf, P.
    • Taylor, R.
    • Brown, C.
    • Wheeler, T.
    • Bronson, K.
  • Source: Soil Science Society of America Journal
  • Volume: 76
  • Issue: 3
  • Year: 2012
  • Summary: Nitrogen is the main nutrient limiting irrigated cotton (Gossypium hirsutum L.) production in the southwestern United States. Canopy spectral reflectance may assess the need for in-season N in irrigated cotton and guide N fertilizer applications. However, calibration of remote sensing indices such as normalized difference vegetative index (NDVI) to the crop's need for N fertilizer is difficult. Well-fertilized reference strips or plots reference NDVI data in the crop area of interest but can result in rank growth and reduced lint yields. Recently, Oklahoma State University developed a calibration procedure of using multiple, sequential, N rate calibration plots, or a ramp approach for wheat (Triticum aestivum L) and corn (Zea mays L.). We tested this approach in irrigated cotton fields in Lubbock County, Texas, in 2008 and 2009. The main objective of this research was to test a calibration ramp approach to determining optimum in-season N fertilizer rates in irrigated cotton in West Texas. Near infrared, red, and amber reflectance was measured with active spectroradiometers at 1 m above the canopy. Wide ranges in soil type and irrigation amounts influenced NDVI much more than N fertilizer rate. Normalized difference vegetative index at mid-bloom and at peak bloom were positively related to N fertilizer rate in only one ramp in each year. These two ramp-years also had significant N fertilizer rate response in lint yield. Ramps that did not have mid- or peak bloom NDVI responses to N rate, likewise had no lint yield response to N rate. In both low irrigation- low N input and in high irrigation-high N input farms, in-season NDVI correctly predicted lint yield response to N fertilizer rate.
  • Authors:
    • Gitz, D.
    • Booker, J.
    • Bednarz, C.
    • Lascano, R.
    • Bufon, V.
  • Source: Irrigation Science
  • Volume: 30
  • Issue: 4
  • Year: 2012
  • Summary: Crop irrigation with subsurface drip (SDI) is increasing in the semiarid Texas High Plains (THP). Information on drip-tubing positioning, irrigation strategies, and wetted soil area is needed to increase rainwater effectiveness when well capacities are inadequate to meet full irrigation requirements. Time and resources necessary to test SDI strategies for different conditions through field experimentation is too large. However, a mechanistic model such as Hydrus-2D can quantify the effect of different installation geometries and irrigation strategies. Our objective was to experimentally validate the Hydrus-2D in an Amarillo soil in THP so that the model can be used to evaluate different irrigation frequency and timing strategies for SDI cotton. Results showed that Hydrus-2D simulated volumetric soil water content within +/- 3% of measured values, and simulation bias represented the smaller portion of the simulation error, indicating that the model can be used to evaluate irrigation strategies.
  • Authors:
    • Chen, X.
    • Zhang, T.
    • Chen, G.
    • Chen, Z.
    • Chen, X.
    • Zhang, T.
    • Chen, G.
    • Chen, Z.
  • Source: Xinjiang Agricultural Sciences
  • Volume: 49
  • Issue: 5
  • Year: 2012
  • Summary: Objective: Study the feasibility of secondary treated waste water for agricultural irrigation in Urumqi. Method: Chinese cabbage and cotton were used as experimental materials and treated respectively with treatment 1 which is control, treatment 2 which is 50% reclaimed water, and treatment 3 which is 100% reclaimed water. POD, CAT, SOD, MDA, and dry weight of Chinese cabbage and production of cotton were detected. Result: Results showed that inhibitory effects of reclaimed water were proportional to the treatment duration and concentration. The dry weight of 50% reclaimed water treated treatment 1, as the order treatment 2 > treatment 1 > treatment 3. Because the nutrients and harmful substances respectively played promotion and inhibition on the growth of Chinese cabbage, treatment 2 growed better; The yields per acre of cotton under three kinds treatments were significant difference, as the order treatment 1 > treatment 2 > treatment 3, that means reclaimed water inhibits the growth of cotton. Conclusion: Reclaimed water showed different effects on different crops. On cabbage, it mainly showed promotive effect, while on cotton, it mainly showed inhibition effect.
  • Authors:
    • Li, Y.
    • Cao, W.
    • Lei, X.
    • Chen, D.
  • Source: Sensor Letters
  • Volume: 10
  • Issue: 1-2
  • Year: 2012
  • Summary: CIDSS, an irrigation decision support system (DSS), was developed to satisfy the need for drip irrigation under plastic film of cotton yield management in Xinjiang, China. It is compartmentalized into four main modules: database management, real-time moisture diagnosis, real-time irrigation decision making, and production management decisions. The present study used the Kriging interpolation method to estimate soil moisture caused by spatial variability. The Least Squares Support Vector Machines (LSSVM) model and an empirical model based on the exponential depletion relation of soil moisture were also employed to predict soil moisture. A cotton production management expert system was realized by embedding C Language Integrated Production System. By integrating the interfaces of the moisture sensor, the automatic meteorological station in the field, and the solenoid valve control system, the present study solved the problem of the data for real-time decision making. Finally, the use of CIDSS was demonstrated through characteristic case studies on cotton areas in Xinjiang Uygur Autonomous Region, China.
  • Authors:
    • Sutton, B.
    • Neilsen, J.
    • Mahan, J.
    • Burke, J.
    • Conaty, W.
  • Source: Crop Science
  • Volume: 52
  • Issue: 4
  • Year: 2012
  • Summary: A plant-based thermal optimum approach to irrigation scheduling provides potential benefits in that water applications are scheduled on the basis of plant response to water status. Such irrigation systems require a defined thermal optimum for the crop and while such optimum values have been identified for cotton (Gossypium hirsutum L.) cultivars in the United States, there is no information of this type for cultivars common in Australian production. This paper outlines a threefold approach to determining the optimum temperature (T-opt) of the commercial Australian cotton cultivar Sicot 70BRF in an Australian production system. It combines the use of a laboratory-based fluorescence assay, field-based net C assimilation rate (A) and stomatal conductance to water vapor (g(s)), and canopy temperature (T-c)-yield relations. The fluorescence assay showed a T-opt between 28 and 30 degrees C while leaf gas exchange rates peaked at a leaf temperature (T l) of 29 degrees C. The T-c-yield relations peaked at 26 degrees C, with yield reductions observed when T-c > 28 degrees C. We conclude the T-opt of the Australian upland cotton cultivar Sicot 70BRF to be 28 +/- 2 degrees C. This T-opt will provide valuable information for use in thermal optimum irrigation scheduling systems.
  • Authors:
    • Batista Almeida de Aquino, R.
    • Lima, T.
    • Lima Neves, J.
    • Berger, P.
    • de Aquino, L.
  • Source: Pesquisa Agropecuaria Tropical
  • Volume: 42
  • Issue: 1
  • Year: 2012
  • Summary: PHOSPHORUS SPLIT APPLICATION ON IRRIGATED COTTONMost regions where cotton is cultivated in Brazil present low soil fertility, especially concerning the available phosphorus (P). This study aimed to evaluate the phosphorus split application on irrigated cotton, for reaching a higher phosphate fertilization efficiency, in comparison to the traditional application at sowing. The experiment was conducted in Quartzarenic Neosol with 22 mg dm(-3) of P (medium availability), in the north region of the Minas Gerais State, Brazil. The design used was randomized blocks, in a (4x3) + 3 factorial scheme, with three replications. Treatments consisted of P2O5 doses (0 kg ha(-1), 30 kg ha(-1), 60 kg ha(-1), 120 kg ha(-1), and 180 kg ha(-1)) and three split applications (80% and 20%; 60% and 40%; 40% and 60% of the P dose applied respectively at sowing and at 35 days after emergence (DAE)), plus the application of 0 kg ha(-1), 60 kg ha(-1), and 120 kg ha(-1) of P2O5 at sowing. The P source was the granulated triple superphosphate, and the P content in the shoots increased according to the doses applied. Nutrient contents in the index leaf, except for P, were not influenced by P levels and split applications. The P content in the index leaf and the number of cotton bolls per plant increased with the increment of P doses, but were not affected by the phosphate fertilizer split application. The application of 40% of the P dose at sowing and the remaining amount split at 35 DAE decreased the cotton boll yield, with no significant effect for the other split applications.
  • Authors:
    • da Silva Soares, L.
    • Freire, A.
    • Alves de Oliveira, F.
    • de Medeiros, J.
    • de Oliveira, F.
  • Source: Revista Ciencia Agronomica
  • Volume: 43
  • Issue: 2
  • Year: 2012
  • Summary: This study was conducted to evaluate the effect of different salinity levels of irrigation water and seed treated with growth regulator on the yield of cotton. It was used an entirely statistical randomized design, in a factorial scheme 5 x 2, with four replications. The treatments resulted from the combination of four salinity levels of irrigation water (S-1-0.5; S-2-2.0; S-3-3.5; S-4-5.0 and S-5-6.5 dS m(-1)) in treated and untreated seeds with growth regulator. The variables were: production of cotton, seed and fiber, 100 seed weight and percentage of fiber. There was not interaction between salinity levels and seed treated. The parameters of cotton production are reduced with the use of water salinity from 3.5 dS m(-1), independent of seed treated or not with growth regulators. Agronomic traits 100 seed weight, percentage of fiber and seed cotton production are not influenced by mepiquat chloride. The seed treatment with growth regulator do not affects the adverse effect of salinity.
  • Authors:
    • Freire, A.
    • Teixeira de Oliveira, M.
    • Alves de Oliveira, F.
    • de Medeiros, J.
    • de Oliveira, F.
  • Source: Revista Ciencia Agronomica
  • Volume: 43
  • Issue: 3
  • Year: 2012
  • Summary: This work was carried out to evaluate the effect of irrigation water at different salinity levels, and of seed treatment with plant growth regulator, on the development of the cotton plant. The experimental design used was completely randomized, arranged in a 5 x 2 factorial scheme with four replications. The treatments resulted from the combinations of five levels of salinity of the irrigation water (S-1-0.5, S-2-2.0, S-3-3.5, S-4-5.0 and 6.5 dS m(-1)) on seeds, both treated and not treated with growth regulator. The evaluated characteristics were: number of leaves, leaf area, height, dry mass of stems, leaves and vegetative parts, specific leaf area and leaf area ratio. There was an interaction between salinity and seed treatments with mepiquat chloride, but only for leaf area and leaf area ratio. All other characteristics decreased with the increasing salinity of the irrigation water, with greater reductions in leaf area (mean of 65.8%) and dry mass of vegetative parts (64%). Seed treatment with mepiquat chloride affected plant development, independent of salinity.
  • Authors:
    • Krutz, L.
    • Park, S.
    • Sij, J.
    • DeLaune, P.
  • Source: Agronomy Journal
  • Volume: 104
  • Issue: 4
  • Year: 2012
  • Summary: Identifying management practices that conserve and protect water resources are very important to a wide variety of stakeholders within semiarid environments. The objective of this study was to develop water management strategies for transitioning tillage systems in cotton (Gossypium hirsutum L.) production within the Texas Rolling Plains when in a subsurface drip irrigation (SDI) system. Five irrigation regimes (0, 33, 66, 100, and 133% evapotranspiration [ET] replacement) and four tillage systems (conventional till, reduced till, no-till, and no-till with a terminated cover crop) were evaluated. The study was conducted for 3 yr and treatments were replicated three times in a randomized complete block design. Lint yields were not affected by the main effects of tillage or the interaction of tillage and ET replacement. In contrast ET replacement was a significant factor for lint yields, irrigation water use efficiency, and net returns. Greatest lint yields and net returns were achieved at 100% ET replacement. Fitted models indicated that optimum lint yields and net returns were achieved at 104.5% ET and 102% ET, respectively. Irrigation at 83% ET was within the 95% confidence interval for lint yield. Net returns were significantly higher for no-till systems compared with conventional till. Thus, adoption of conservation tillage systems should not negatively affect lint yield or net returns in deficit irrigated SDI cotton systems within the Texas Rolling Plains, particularly during the transition from intensively tilled systems to conservation tilled systems.
  • Authors:
    • de Figueiredo, M.
    • Figueiredo, M.
    • Detomini, E.
  • Source: Revista de Politica Agricola
  • Volume: 21
  • Issue: 1
  • Year: 2012
  • Summary: The main purpose of this study is to identify the optimum allocation of limited amount of land and irrigation water across a number of alternative farm enterprises, maximising the whole-farm profitability by considering present relative prices, changes in river water availability, irrigation system efficiency and a highly variable climate. It was developed an optimisation model by using linear programming language to maximise the whole-farm profit of farm located in Wee Waa (NSW, Australia), for three different scenarios (dry, average and wet years) over two seasons. The whole-farm profit is highly sensitive to climate variability and also to prices and yields variability, especially in relation to cotton.