Characteristics and influencing factors of crop coefficient for drip-irrigated cotton under plastic-mulched condition in arid environment

Abstract

Crop coefficient K c is a very useful and widely used variable in evapotranspiration estimation in cropland. Traditional methods in calculating K c are based on field water balance, which is limited by long measurement interval and small study area. In addition, there is the need for K c under new agronomy practice such as plastic mulching and drip irrigation in arid environments. This study calculated and analyzed K c of a drip-irrigated and plastic-mulched cotton field in Aksu Oasis of the arid Tarim River Basin, China, and its relationships with several crop-, soil-and management variables such as relative growth days RGD , leaf area index LAI , extractable soil water ESW , and irrigation, based on two years' observations. The results showed that daily K c varied within the range of 0.08 1.28, with an average of 0.54 for the entire cotton growth season, in 2013 and 2014. Compared to non-mulched condition already published, the K c of mulched cotton for the entire growth season decreased by 16 to 39 . The largest reductions in K c due to plastic mulch were found in the initial and developmental growth stage. K c could be calculated by a third-degree polynomial model in relation to RGD, which was satisfactorily validated and can be used in other studies under the same or similar pedo-climatic and management conditions. Cotton LAI and ESW were found to be important factors influencing K c , particularly their critical values of 3.0 in LAI and 0.5 for ESW. Moreover, the results showed that irrigation significantly increased K c , i.e., 29 on average, partly due to arid advection. This study provided up-to-date and detailed information on cotton crop coefficient under plastic mulching and drip irrigation conditions in arid environment, and it is useful for improved management of agricultural water resources.

Multi-Objective Calibration of a Distributed Hydrological Model in a Highly Glacierized Watershed in Central Asia

“…In this study, we chose three objective functions for model calibration (LogNS, WBI and MARD), as our purpose is to study the general hydrological process (i.e., sources of flow and flow frequency) that serve as water resources management in the catchment. In our estimation, these three objectives In the SDKR basin, the main contributions of glacier and snow melt occur from June to August, which is consistent with the agricultural irrigation season in the downstream Aksu region and thus contributes to the development of downstream oasis agriculture [61]. It is clear that the amount and spatiotemporal distribution of water resources have become the primary prerequisites for sustainable development of agriculture in arid areas.…”

“…In July and August, glacier melt water accounts for 33% and 48% of the streamflow, respectively. In the SDKR basin, the main contributions of glacier and snow melt occur from June to August, which is consistent with the agricultural irrigation season in the downstream Aksu region and thus contributes to the development of downstream oasis agriculture [61]. It is clear that the amount and spatiotemporal distribution of water resources have become the primary prerequisites for sustainable development of agriculture in arid areas.…”

Improvement And Modernization of Agricultural Irrigation. Uzbekistan Case Study

“…The advantages of using a modern drip irrigation system derive from the fact that only the root part of the plant is moistened. Therefore, the amount of water lost due to evaporation, runoff and deep percolation is reduced [15]. Water consumption per hectare of cotton is 3,5 thousand m 3 in drip irrigation, 8,5-9 thousand m 3 in conventional irrigation, which saves 5-5,5 thousand m 3 or 60-65% of water.…”

Physiological and biochemical appraisal for mulching and partial rhizosphere drying of cotton

“…Moreover, activities of antioxidant enzymes in cotton were higher under mulching than under no mulching treatments (Meloni et al, 2003). Worldwide, black plastic mulching is the most commonly applied (Ngouajio and McGiffen, 2004;Ai et al, 2018). Wheat/paddy straw mulching can also be used and have been reported to improve the growth, development and yield of peanut and tomato compared to black plastic mulching or no mulching (Arin and Ankara, 2001;Ghosh et al, 2006).…”