| In order to establish the best mode for plastic-film mulching and improve the rainfall use efficiency of potato production in loess hilly region, the effects of mulching degree, mulching time, ridge type, and ridge height on yield, economic benefit, and water use efficiency were investigated under different annual rainfall conditions in 2011—2013. The results showed that mulching degree,
mulching time, and ridge type were the key factors for potato production, and ridge height significantly influenced on yield in dry year, with the order of mulching degree ＞ ridge type ＞ mulching time ＞ ridge height. Mulching degree significantly influenced on yield, economic benefit and water use efficiency with the following order: whole plastic-film mulching ＞ half plastic-film
mulching ＞ no mulching. Compared with no mulching, the yield, weight of large and medium tuber, and water use efficiency of whole plastic-film mulching were increased by 21.2%, 23.63%, and 26.19%, and that of half plastic-film mulching by 16.1%, 10.91%, and 16.62%, respectively. Ridge type also had significant influence on yield. Autumn mulching showed the largest effect among three mulching time. Compared with mulching before sowing, yield and water use efficiency of autumn were increased by 15.31% and 14.56%, respectively. The effect of ridge height on potato production depended on annual rainfall. High ridge showed favorable effect in rainy years, whereas the opposite was true in the drought year. Under the average annual rainfall from 2011 to 2013, yield and water use efficiency of low and medium ridge were increased by 1.72%, 1.79%, 3.61%, and 2.76%, as compared with the high ridge. The yield, economic benefit, and water use efficiency of double and medium ridges and ridge planting with whole plastic-film mulching were 49.16%, 78.06%, and 56.79% higher than that of no mulching, and 23.07%, 43.93%, and 24.25% higher than that of ridge side planting with whole plastic-film mulching. These method is suggested be used for potato production in loess hilly region. |