Optimizing water–nitrogen productivity in rain-fed summer maize production in semi-humid and drought-prone area: Sustainable approach by integrating straw mulching and suitable fertilization depth

Abstract

Context or problem

Achieving high yields and efficient water–nitrogen utilization while increasing net economic benefits is crucial for sustainable agricultural production.

Objective or research question

The deep placement of fertilizer is considered an effective strategy for improving crop growth and yield formation. However, it is still not clear how water–nitrogen utilization and economic benefits respond to fertilization depths under different planting methods in summer maize fields.

Methods

A three-year field experiment was conducted in a semi-humid and drought-prone area to assess the effects of different fertilizer placement depths of 5 cm (D5, conventional fertilization), 15 cm (D15), 25 cm (D25), and 35 cm (D35) under two planting conditions (straw mulching (S) and bare land planting (N)) on the soil water, mineral nitrogen (NH₄⁺-N and NO₃^--N) and root distribution, leaf photosynthetic rate, yield formation, resource utilization, and economic benefits of summer maize.

Results

Compared with bare land planting, straw mulching improved the soil water content and spatiotemporal distribution, thereby affecting water storage and moisture preservation. Compared with other fertilization depths, D15 improved the mineral nitrogen content and distribution in the soil to promote root growth and nitrogen absorption (4.9–12.5 %). In addition, D15 increased the nitrogen content and photosynthetic rate of summer maize leaves to promote increases in the grain filling rate (3.7–10.0 %) and yield (6.6–18.6 %). Moreover, the combination of straw mulching and D15 significantly improved the nitrogen utilization efficiency (0.7–11.3 %), water utilization efficiency (6.2–36.6 %), net economic benefit (233.5–981.2 $ ha^–1), and input–output ratio (2.4–67.9 %) in summer maize.

Conclusions

These results clearly indicate that in the semi-humid and drought-prone area of China, a fertilization depth of 15 cm combined with straw mulching is beneficial for improving the yield, resource utilization, and economic benefits of rain-fed summer maize.

Implications or significance

This management approach can replace the traditional fertilization depth under bare land planting to achieve high yields and effective resource utilization in the semi-humid and drought-prone area, and thus promote the sustainable development of rain-fed agriculture.