Plastic film mulch for half growing-season maximized WUE and yield of potato via moisture-temperature improvement in a semi-arid agroecosystem

Effects of plastic mulching in ridges and furrows for varying durations on yield and water use efficiency (WUE) in potato were investigated in rainfed areas of north-western China in 2009 and 2010. The experiment comprised four mulched treatments (M50, M65, M80/85, and Mw - indicating plastic film mulch for 50, 65, and 80/85 d after sowing, and whole growth season, respectively - after which mulch in furrows was removed) and a non-mulched control. The results showed that film mulching warmed topsoil and increased topsoil water content. The daily mean topsoil temperature in mulched plots was 2.5-3.2 degrees C higher than that in controls during the early growing season (sowing-emergence). the difference became less as the plant canopy grew; on some days later in the season, the difference was even negative (i.e. the topsoil temperature in mulched was lower than in control plots). Seedlings under mulching emerged 8.1-11.7 d earlier than those in controls due to the increased topsoil temperature and moisture in the early season. Mulching also prolonged the duration from seedling to maturity by 0.7-15.0 d and significantly increased plant height, leaf area index, and dry matter. Compared to non-mulched plots, yields in mulched plots increased by 33.9-92.5% and 62.9-77.8% in 2009 and 2010, respectively, and corresponding WUEs improved by 41.4-112.6% and 45.9-70.6%. Both tuber yield and WUE were highest in M65. The data indicate that mulching for about 65 d after sowing was ideal to optimize soil moisture and soil temperature and in turn to improve potato productivity and WUE in this semi-arid rainfed region. (C) 2011 Elsevier BM. All rights reserved.