Abstract
Drip irrigation under plastic mulch is widely used in Xinjiang, Northwest China. It can not only save water, but also reduce nutrient loss and improve fertilizer utilization. However, it is not clear whether the leaching occurs or not, what is the leaching amount? What is the relationship among fertilization, irrigation regimes, loss, cotton absorption, and cotton field under different fertilization and irrigation management under drip irrigation? Studying these issues not only provides reference for the formulation of fertilization and irrigation systems, but also is of great significance for reducing non-point source pollution. A long-term positioning experiment was conducted from 2009 to 2012 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (Gossypium hirsutum L.) under different N fertilizer and irrigation amounts. The treatments were designed comprising Control (CK,0 N, 0 P, and 0 K with an irrigation of 480 mm) and the following three other treatments: (1) Conventional fertilize and irrigation (CON, 357 kg N hm–2, 90 kg P hm–2, 0 kg K hm–2, and irrigation of 480 mm); (2) Conventional fertilization and Optimizing irrigation (OPT, 357 kg N hm–2, 90 kg P hm–2, 62 kg K hm–2, and irrigation of 420 mm); and (3) Optimizing fertilization and irrigation (OPTN, 240 kg N hm–2, 65 kg P hm–2, 62 kg K hm–2, and irrigation of 420 mm). The results found that the leaching would occur in arid area under drip irrigation. The loss of total N, NH4+, P, N and P loss coefficient was higher under conventional fertilize and irrigation treatment while the loss of NO3- was higher under conventional fertilization and optimizing irrigation treatment. The correlations among N, P absorption by cotton, loss of NH4+ and total phosphorus were quadratic function. The total nitrogen loss and cumulative nitrogen application was lineally correlated. The loss of NO3- and cumulative nitrogen application was exponential. The nitrogen and phosphorus absorption by cotton under conventional fertilization and optimizing irrigation treatment was 24.53% and 35.86% higher than that in conventional fertilize and irrigation treatment, respectively. The cotton yield under conventional fertilization and optimizing irrigation treatment obtained higher than that in other three treatments. Therefore, the conventional fertilization and optimizing irrigation treatment was the optimal management of water and fertilizer in our study. These results demonstrate that reasonable water, nitrogen and phosphorus fertilize could not only effectively promote the absorption of nitrogen and phosphorus, but also reduce nitrogen and phosphorus losses under drip fertigation and plastic mulching.
Highlights
In recent decades, non-point source pollution (NPSP) has become a major threat to the water quality of global water resources [1,2,3]
NO3- loss in OPT (Conventional fertilization and Optimizing irrigation) treatment was higher than that in CON (Conventional fertilization and irrigation) treatment, probably because the amount of irrigation in OPT treatment was less than that in CON treatment, so the soil temperature was higher in OPT treatment than CON treatment [31], and the transformation of nitrogen fertilizer into soil was faster, NH4+ was rapidly converted to NO3, so the NO3- loss in OPT treatment was higher than CON treatment
Drip irrigation could reduce the waste of water resources, it is not clear whether the leaching occurs and the characteristics of nitrogen and phosphorus loss, especially in arid area
Summary
Non-point source pollution (NPSP) has become a major threat to the water quality of global water resources [1,2,3]. Non-point source pollution (NPSP) is influenced by lots of factors, such as soil type, land use, climate, hydrology, and management [4]. Total nitrogen (TN) and total phosphorus (TP) loads are regarded as the main two indexes in water quality assessment in China [6,7]. Nitrogen (N) and phosphorus (P) generally come from fertilizers in the farmland. Excessive application of nitrogen (N), phosphorus (P) being added to aquatic environments, which causes a series of problems such as eutrophication of water bodies, lower soil productivity, and poor quality water for drinking and other purposes [8,9,10,11,12]. Most studies of soil and nutrient losses have been done. The soil and nutrient losses in the underground leaching water by drip irrigation are less
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
