Effects of farming practices on yield and crop water productivity of wheat, maize and potato in China: A meta-analysis

Crop yields are significantly restricted by the shortage of water resources in semi-arid and semi-humid regions around the world. Farming practices like ridge-furrow planting with plastic film mulching (RFFM) can effectively improve crop yield and crop water productivity (WP) by enhancing soil moisture and temperature availability. This meta-analysis study collected and analyzed the data of 964 observations published in 90 peer-reviewed papers to investigate the effects of various farming practices, i.e., RFFM, ridge-furrow planting without film mulching (RF) and flat planting with film mulching (FM) in comparison with conventional flat planting without film mulching (F), on yield and WP of three major crops (wheat, maize and potato) in China, in terms of planting region, climatic condition, altitude, soil type and seeding method. The results showed that RFFM, RF and FM improved mean crop yields by 33.8 %, 16.6 % and 27.0 %, and increased mean WP of crops by 35.8 %, 17.5 % and 27.8 % compared with F, respectively. Increases in crop yields under RFFM, RF and FM were greater in regions with seasonal rainfall <400 mm than in regions with seasonal rainfall>400 mm. RFFM, RF and FM performed better in Northwest China than in North-central and other regions of China. Among the three crops, potato obtained the greatest increases in yield and WP under ridge-furrow planting or film mulching. For clay soils and high altitude regions, the two film mulching practices (FM and RFFM) attained greater yield increases. With regards to the two ridge-furrow practices (RFFM and RF), it is better to plant crops in the furrow than on the ridge. In short, RFFM was most effective to improve yield and WP of wheat, maize and potato among the farming practices. These findings have important implications for choosing appropriate field management practices to improve crop yield and crop water productivity in China.