Industrial Organic Wastewater through Drip Irrigation to Reduce Chemical Fertilizer Input and Increase Use Efficiency by Promoting N and P Absorption of Cotton in Arid Areas

Abstract

The use of industrial waste as an agricultural resource is important for clean and sustainable agriculture. We assumed that industrial organic wastewater coupled with chemical fertilizer would increase cotton yield by enhancing nutrients absorption and utilization. To test this hypothesis, a two-year (2019–2020) field trial was conducted to assess the impacts of CK (0 kg ha−1), chemical fertilizer (CF) (N-P2O5-K2O: 228-131-95 kg ha−1), chemical fertilizer + organic wastewater (F0.6 (60%CF + OW: 1329 kg ha−1), F0.8 (80%CF + OW), F1.0 (CF + OW), F1.2 (120%CF + OW) and F1.4 (140%CF + OW)) on nutrient absorption and distribution, fertilizer use efficiency and cotton yield under drip irrigation system. Compared with CF, the soil organic matter, NH4+-N and AV-K increased significantly after F0.8-F1.4 treatments. The absorption of nitrogen (N), phosphorus (P) and potassium (K) by plants after dripping organic wastewater (F0.8-F1.4) increased by 1.1–11.2% as compared with CF (F0.6, CF < F0.8, F1.0 < F1.2, F1.4). Under F0.8, treatment resulted in a higher distribution rate of N, P and K in reproductive organs compared with other counterparts. In addition, drip application of organic wastewater promoted the absorption of magnesium (Mg) and zinc (Zn) in leaves and Fe in roots with higher translocation of Zn and boron (B) to reproductive organs compared with other treatments. The absorption of N, P and K was positively correlated with Mg, negatively correlated with calcium (Ca) and sulfur (S), and positively correlated with manganese (Mn) and iron (Fe). The yield and fertilizer utilization rate of cotton were higher at F0.8. Conclusively, the use of 1329 kg ha−1 organic wastewater (organic mattered ≥ 20%, humic acid ≥ 20 g L−1, Bacillus subtilis ≥ 2 × 108 L−1) combined with chemical fertilizer (N-P2O5-K2O) at (182-104-76 kg ha−1) reduces the application of chemical fertilizer and can increase utilization efficiency of chemical fertilizer with a high cotton yield under mulch drip irrigation in arid regions.