Effects of straw mulching and plastic mulching on maize yield and crop water productivity in China: A meta-analysis

With the increasing severity of global climate change and water scarcity, improving crop water productivity (WPc) has become essential for sustainable agriculture. As a major staple crop, maize (Zea mays L) plays a crucial role in China’s food security. Straw and plastic mulching are widely used to alleviate water stress and improve maize yield and WPc; however, comprehensive comparisons under varying environmental and management conditions are limited. This study employed meta-analysis to evaluate the effects of straw and plastic mulching on maize yield and WPc across different climatic zones, soil types, and agronomic practices in China. The results revealed that plastic film mulching significantly enhanced yield and WPc when growing season precipitation was ≥ 600 mm, temperature ≤ 19°C, and annual sunshine ranged from 2300 to 2600 h. In contrast, straw mulching performed better when precipitation was ≤ 400 mm, temperature ranged from 19 to 23°C, and sunshine duration exceeded 2600 h. Plastic mulching was more effective across various soil types, especially under conditions of spring sowing, high planting density (>6.75×104 plants·ha−1), low nitrogen input (<120 kg·ha−1), and irrigation. Straw mulching effectiveness was primarily influenced by temperature and planting density, while plastic mulching was governed by soil organic matter and nitrogen input. Economic analysis showed that plastic mulching yielded higher profits under rain-fed conditions, whereas straw mulching was more profitable under irrigation due to lower costs. These findings offer practical guidance for region-specific mulching strategies, contributing to efficient water use, enhanced crop productivity, and sustainable farming.