Optimization of water and nitrogen management in wheat cultivation affected by biochar application − Insights into resource utilization and economic benefits

Abstract

In the context of global climate change and natural resource scarcity, agricultural production is facing multiple challenges in improving crop yields and optimizing natural resource use. It is of great practical significance to optimize agricultural practices to achieve sustainable agricultural development. In this study, a two-year winter wheat field experiment was conducted in the Guanzhong Plain, Shaanxi, China, from 2020 to 2022 to assess the effects of biochar, irrigation, and N fertilizer rates on the yield, water-nitrogen use efficiency, and economic benefits of winter wheat. Specifically, biochar was applied to winter wheat at 30 t ha⁻¹ in combination with two irrigation application rates, including regular irrigation (I₁₀₀; actual evapotranspiration) and deficit irrigation (I₈₀; 0.8 actual evapotranspiration), and three different N fertilizer rates at 210 (N_H; conventional applied N rate by local farmers), 160 (N_M; moderate N rate), and 110 kg ha⁻¹ (N_L; low N rate). The control groups in this study consisted of experimental plots under the N_M and N₀ (no N) without biochar application. The aboveground dry matter mass (ADM), yield, and net ecosystem economic budget (NEEB) of winter wheat showed increasing trends with increasing N application rates without significant differences between the N_H and N_M treatments. On the other hand, the water use efficiency (WUE), agronomic N fertilizer use efficiency (aNUE), and N fertilizer recovery efficiency (NRE) showed increasing-decreasing trends with increasing N fertilizer rates, reaching the highest values under the N_M treatment scenario. The biochar addition significantly increased the winter wheat yield and WUE (P<0.05). On the other hand, the I₈₀ treatment resulted in higher WUE and irrigation water use efficiency (IWUE) than those under I₁₀₀ by 5.63 and 13.52 %, respectively. TOPSIS results indicated that the combined I₈₀B₁N_M treatment was the optimal winter wheat management practice, maintaining high productivity while improving resource use efficiency and economic benefits. The results of the present study provide an important scientific basis and guidance for ensuring efficient and high-quality agricultural products in the Guanzhong Plain and other regions in China with similar climatic characteristics.