• Authors:
    • Evans, N.
    • Agbola, F.
  • Source: Agricultural Systems
  • Volume: 107
  • Year: 2012
  • Summary: Although water markets have been in operation for nearly 30 years, previous empirical studies have ignored farmer's land use response to water trading in the Murray-Darling Basin (MDB), Australia. A Nerlovian partial adjustment model of rice and cotton acreage response in the MDB were specified and estimated using data for the period 1965-2008. The results indicate that acreage response for rice and cotton with respect to the price of water are inelastic in both the short- and long-run. The findings of this study bring into question the effectiveness of water trading scheme as the primary means of ensuring the efficient use of water and highlight the need for other complementary measures in the MDB. The results of this study highlight the complex interdependencies of many factors that influence farmer's land use decisions and draw an important conclusion that although water trading has increased the efficient use of irrigated water, its impact on farmers' land use decisions has been too small to stimulate any significant reduction in irrigated water usage in the MDB. (C) 2011 Elsevier Ltd. All rights reserved.
  • Authors:
    • Yazdanpanah, N.
    • Kouhi, N.
    • Asadi, R.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 10
  • Issue: 1
  • Year: 2012
  • Summary: With population growing throughout the world, it is necessary to optimize water use especially in agriculture land. In order to determine water use efficiency (WUE) of cotton using micro irrigation system, a field experiment was conducted in the Agricultural and Natural Resource Research Institute of Orzoueyeh, Kerman province. The experiment was carried out in split plot design based on Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of crop water requirements (i.e. I-1 I-2 and I-3, that are irrigation based on 125, 100 and 75% water requirement, respectively) in main plot and two tape position as sub plot including conventional (r(1)) and alternative (r(2)) patterns. All treatments were assessed for productivity, water use and its efficiency, and economic issues, as well. The results showed that the yield obtained from I-1 was 379 and 1204 kg ha(-1) higher than that of I-2 and I-3, respectively. In addition, the obtained yield due to r(1) system was 377 kg ha(-1) more than in the r(2) pattern. However, interaction between treatments on crop yield indicated that the I(1)r(1) treatment resulted in the maximum yield. Despite of use water equality in sub plots, WUE in r(1) was 16% higher than in r(2). However, economic assessment exhibited that system cost in the r(2) in comparison with the r(1) was 11% lower.
  • Authors:
    • Salakinakoppa, S.
    • Basavanneppa, M.
    • Biradar, D.
  • Source: Journal of Cotton Research and Development
  • Volume: 26
  • Issue: 1
  • Year: 2012
  • Summary: A field experiment was carried out during kharif 2006-2007, 2007-2008 and 2008-2009 at Agricultural Research Station, Siruguppa to study the response of Bt cotton to spacing and fertilizer levels under irrigated ecosystem. The results revealed that among the spacings, closer spacing of 90*45 cm produced significantly superior seed cotton yield (2243 kg/ha) over wider spacing of 90*90 cm (1867 kg/ha) and it was at par with 90*60 cm (2121 kg/ha). Among the fertilizer levels, application of 125 per cent NPK registered higher seed cotton yield over 75 per cent NPK but at par with application of 100 per cent NPK. On the contrary the ancillary data indicated that, higher seed cotton yield/plant (136.11 g/pl) and more bolls (40.46/pl) were observed in wider row spacing of 90*90 cm as compared to other spacings. In case of fertilizer levels more seed cotton yield/plant was observed in application of 125 per cent NPK (130.40 g/pl) as compared to 75 and 100 per cent fertilizer levels. Similar trend in bolls/plant, sympodia and boll weight were found as that of yield. Further, higher gross return (Rs.56774/ha), net returns (Rs.30837/ha) and B:C ratio (2.20) was recorded in closer spacing of 90*45 cm as compared to 90*90 cm. Among the fertilizer levels, application of 125 per cent RDF recorded maximum gross return (Rs.55256/ha), net returns (Rs.29415/ha) and B:C Ratio (2.15) which was significantly superior to 75 per cent NPK but at par with 100 per cent NPK. From the results, it can be concluded that, Bt cotton responds to closer spacing of 90*45 cm with the application of 100 per cent NPK for realizing higher yield and monetary advantages.
  • 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:
    • 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:
    • Chehbouni, A.
    • Lepag, M.
    • Jarlan, L.
    • Ezzahar, J.
    • Erraji, T.
    • Khabba, S.
    • Er-Raki, S.
    • Hanich, L.
  • Source: Acta Horticulturae
  • Issue: 951
  • Year: 2012
  • Summary: Sap flow measurements based on heat balance method gives a direct measurement of the mass flow rate of sap in the stem. However, extrapolation of these measurements from the stem to the field scale is an important challenge. In this study, 15 branches of citrus trees with different diameters were equipped with Dynamax sap flow gauge. These individual branch measurements have been after extrapolated to the canopy transpiration by using two up-scaling methods. The first one uses the relationship between sap flow and branches diameter and the second one uses the distribution of the branch diameter in the orchards. The results showed a good agreement between the two methods estimates (R 2=0.95). A comparison between scaled-up transpiration from sap flow and measured evapotranspiration (ET ed) by eddy covariance showed an average daily difference of about 0.87 mm/day which represents 25% of ET ed. This substantial amount of water was lost through soil evaporation and part of it could be saved by improving the drip irrigation management.
  • Authors:
    • Frisvold, G. B.
    • Konyar, K.
  • Source: Water Resources Research
  • Volume: 48
  • Issue: 5
  • Year: 2012
  • Summary: This study examined how agriculture in six southwestern states might adapt to large reductions in water supplies, using the U.S. Agricultural Resource Model (USARM), a multiregion, multicommodity agricultural sector model. In the simulation, irrigation water supplies were reduced 25% in five Southern Mountain (SM) states and by 5% in California. USARM results were compared to those from a "rationing" model, which assumes no input substitution or changes in water use intensity, relying on land fallowing as the only means of adapting to water scarcity. The rationing model also ignores changes in output prices. Results quantify the importance of economic adjustment mechanisms and changes in output prices. Under the rationing model, SM irrigators lose $65 in net income. Compared to this price exogenous, "land-fallowing only" response, allowing irrigators to change cropping patterns, practice deficit irrigation, and adjust use of other inputs reduced irrigator costs of water shortages to $22 million. Allowing irrigators to pass on price increases to purchasers reduced income losses further, to $15 million. Higher crop prices from reduced production imposed direct losses of $130 million on first purchasers of crops, which include livestock and dairy producers, and cotton gins. SM agriculture, as a whole, was resilient to the water supply shock, with production of high value specialty crops along the Lower Colorado River little affected. Particular crops were vulnerable however. Cotton production and net returns fell substantially, while reductions in water devoted to alfalfa accounted for 57% of regional water reduction.
  • Authors:
    • Arriaga-Sevilla, J.
    • Durán-Zuazo, V. H.
    • García-Tejero, I.
    • Muriel-Fernández, J. L.
  • Source: Agronomy for Sustainable Development
  • Volume: 32
  • Issue: 3
  • Year: 2012
  • Summary: Water shortage is becoming a severe problem in arid and semi-arid regions worldwide, reducing the availability of agricultural land and water resources. Deficit irrigation strategies can improve water-use efficiency and the sustainability of agro-ecosystems, although it is important to model the effects on yield loss due to irrigation water restrictions. This work estimates the water production function in citrus trees, determining the relationship between plant water stress and yield depression, as well as establishing a mathematical model for each phenological stage considered (flowering, fruit growth and ripening), and for the entire productive process. For three consecutive years (2006-2008), four regulated deficit irrigation treatments plus a control (100% crop water evapotranspiration (ET C)) were implemented in 13-year-old citrus trees ( Citrus sinensis L. Osb. cv. Navelina). Different water production functions were determined for each phenological stage, establishing the relationship between the irrigation water stress and crop yield. Our results show that the fruit growth and flowering stages were the most sensitive periods in relation to irrigation water deficit and yield loss. Water stress close to 50% of ET C during the flowering stage would impose a yield loss of up to 20%, whereas this same water stress level during the fruit growth or ripening stages would result in yield losses of nearly 10% and 6%, respectively. The adjustment with cross terms ( r2=0.87) estimated the yield loss with good accuracy, being very similar to data measured in each study season. Consequently, the combined effect of deficit irrigation in different stages would be an additive-multiplicative model, considering that the effect of water stress in previous periods determined the crop yield response. Our model indicated that the crop water production function under deficit irrigation programmes would have a quasi-linear relation for water deficits below to 40% ET C. The previous model functions did not enable us to establish an accurate relationship when the water stress was applied in different phenological stages. Thus, this new interpretation is valuable to improve our knowledge and predict the impact of regulated deficit irrigation and have potential application in precision water stress and sustainable irrigation scheduling for citrus.
  • Authors:
    • Khavari, F.
    • Ghaderi-Far, F.
    • Sohrabi, B.
  • Source: International Journal of Plant Production
  • Volume: 6
  • Issue: 1
  • Year: 2012
  • Summary: Restricted water resources are a limiting factor for irrigation applications throughout the world. The effects of irrigation regimes (amount) on cotton lint yield are known, but there is little information on the effect of irrigation regimes on seed quality of cotton. In this study, the effects of deficit irrigation after the onset of flowering on lint yield and seed quality of cotton (Gossypium hirsutum L.) with a drip irrigation system were evaluated during 2006 and 2007 in the northern Iran. After the onset of flowering, four irrigation regimes (0, 40, 70 and 100% of Class A pan evaporation (%PE)) were applied when the cumulative evaporation amount from class A pan reached approximately 40-50 mm. Lint yield showed a quadratic response to %PE and maximum lint yields were achieved with 82 and 91% PE irrigation regimes in 2006 and 2007, respectively and seed quality (based on standard germination and seed vigor tests) increased with a decrease in deficit irrigation. Thus when the amount of applied water was reduced by 30 (70% PE) and 60% (40% PE), decrease in lint yield was about 4 and 14%, respectively. The results of this study showed that irrigation treatments of 40-70% PE would be optimum for lint yield and seed quality production under drip irrigation.
  • Authors:
    • Hague, S.
    • Hequet, E.
    • Smith, W.
    • Ng, E. H.
    • Gregory, K.
  • Source: Crop Science
  • Volume: 52
  • Issue: 3
  • Year: 2012
  • Summary: The U.S. cotton (Gossypium spp.) industry has shifted focus in recent years to an export market, necessitating further development of upland cotton (G. hirsutum L.) cultivars with superior fiber properties to maintain competitiveness. This study was conducted to compare both fiber and yarn performance of upland cotton genotypes with similar average fiber length but enhanced fiber bundle strength (Str) with two high quality commercial controls, 'FM 832LL' and 'DP 491'. The high Str strains and commercial upland controls were grown in Weslaco, TX, during the summers of 2009 and 2010 with standard agronomic practices for south Texas, including furrow irrigation. Plots were spindle-machine harvested, seedcotton ginned on a research gin without a lint cleaner, and lint and yarn tested at the Fiber and Biopolymer Research Institute (FBRI) in Lubbock, TX. Lint and yarn data collected included high volume instrument (HVI) and advanced fiber information system (AFIS) derived data and ring spun yarn data (mini-spinning protocol). Years were different for almost every fiber and yarn property except Str, immature fiber content (IFC), yarn tenacity (Ten), work required for yarn breakage (Work to Break) and the number of thin places per kilometer that are at least 50% smaller in diameter than adjacent portions of yarn (Thin). All of the high Str strains had higher Ten in 2009 than the controls and 9 of the 11 had higher Ten in 2010. The high Str genotypes resulted in more even yarns (as determined with the Uster Tester 3 [Uster Technologies]).