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Crop residue returning (CRR) is known to improve the soil environment and thus increase crop production. However, the impacts of CRR on wheat (Triticum aestivum L.) yield have been contrary at times due to the differences in climatic conditions, soil traits, and management practices. These effects were evaluated using 351 paired observations published in 161 papers comprising studies conducted in 19 provinces (autonomous regions) of China. No publication bias or extreme values were found in the data, indicating that the analysis results are highly reliable. Compared with the practice of no crop residue returning (NCRR), the practice of CRR increased wheat yield significantly, on average by 8.29%, and proved more beneficial in Northwest China and in regions with average annual precipitation of 200 to 400 mm, average annual temperatures >11°C, sandy loam soil, and rotation with legumes (soybean [Glycine max (L.) Merr.]–wheat and pea [Pisum sativum L.]–wheat). The following aspects of CRR and crop management conferred greater benefits in yield: continuing the practice for 3 to 6 yr (compared with 1–2, 7–10, and ≥11 yr), using the residues at 3 to 6 t ha−1 (compared with <3, 6–9, and > 9 t ha−1), chopped straw (compared with intact straw), rainfed conditions (compared with irrigated conditions), and applying N at 200 to 300 kg ha−1 (compared with <100, 100–200, and >300 kg ha−1). The yield increase was significantly higher when the residues were returned in the form of mulch (12.56%) and for spring wheat (11.90%) than plowing them back into soil (4.53%) and for winter wheat (7.09%). The meta‐analysis thus confirms the benefits of CRR in higher wheat yields in China and also suggests that the benefits of CRR are site specific. [ABSTRACT FROM AUTHOR]

Water scarcity and high evaporation are critical factors affecting crop growth and yield. Sustainable production of jujube (Ziziphus jujuba Mill.) plantations is essential for economic development and environmental protection in arid desert areas of Northwest China. However, few studies have investigated how plastic film mulching combined with sand tube irrigation (STI) affects soil surface wetted area, soil water indices, crop water consumption, yield, water use efficiency (WUE), and fruit quality in jujube plantations in arid desert areas. Therefore, a 2-year field experiment was conducted with three levels of STI (SW1, 300 m3 ha–1; SW2, 375 m3 ha–1; SW3, 450 m3 ha–1) and surface drip irrigation as a control (DW3, 450 m3 ha–1). Compared with surface drip irrigation, STI significantly decreased (p < 0.05) surface wetted area, and SW3 significantly increased soil water storage in the 60–100 cm layer as well as the 0–100 cm soil layer. Sand tube irrigation also alleviated the soil water deficit in the 60–100 cm soil layer and each soil layer before irrigation and increased yield by 0.6% and WUE by 27.3% on average. The highest yield and WUE were in SW3 in both years. Crop water consumption of jujube trees increased and then decreased during the growth period in both years and reached a maximum in the fruit swelling period. With STI, vitamin C content increased by 9.8%, soluble protein content by 15.6%, and the sugar to acid ratio by 12.2% in both years. Overall, application of STI increased jujube yields and WUE and improved fruit quality by increasing soil water storage and reducing soil water deficit. Thus, this study demonstrates STI can increase economic and ecological benefits, and also provides guidelines to apply STI and improve agricultural water productivity. [Display omitted] • Sand tube irrigation (STI) can increase soil water storage. • STI can improve jujube yield, WUE, and fruit quality. • STI can serve as an ideal alternative irrigation technology in jujube production. • This experiment presented another pathway for agricultural water loss. [ABSTRACT FROM AUTHOR]