耕作方式对华北冬小麦.夏玉米周年产量和水分利用的影响

在冬小麦季设置秸秆不还田翻耕(CT)、秸秆还田翻耕(CTS)、秸秆还田旋耕(RTS)和免耕秸秆覆盖(NTS)4种处理,研究耕作方式对华北小麦-玉米两熟区作物周年产量和水分利用的影响。结果表明:耕作方式对当季冬小麦产量和水分利用影响显著,对夏玉米产量和水分利用影响不大,但秸秆还田提高了夏玉米产量。RTS、CTS、CT 3个处理小麦季产量差异不显著,而NTS由于有效穗数不足,产量显著低于其他处理;与CT相比,NTS周年产量平均减产5.13%,RTS增产2.69%,CTS增产2.33%。耕作方式对当季小麦土壤水分含量影响大,而对后茬夏玉米土壤水分含量的影响较小。NTS提高了小麦季土壤水分含量,增加了土壤储水量,与CT相比,0~60 cm土壤储水量2010年和2011年分别增加39.07 mm和26.65 mm。从耗水构成来看,土壤水在冬小麦耗水中所占比例最大,其次为灌水和降水;而夏玉米耗水以降水为主,且降水中有一部分转化为土壤水储存起来。NTS提高了冬小麦季土壤储水量,降低了土壤水分的消耗,冬小麦季耗水最少。与CT相比,NTS小麦季平均节水22.40 mm,周年耗水量也以NTS最少;但NTS冬小麦产量降低导致其小麦季和周年水分利用效率均最低。从作物周年产量和水分利用的角度来看,如何提高免耕秸秆覆盖小麦季产量,进而提高周年产量,发挥其节水优势,是该耕作模式在华北地区冬小麦?夏玉米两熟区推广应用亟需解决的关键问题。

Effects of tillage methods on crop yield and water use characteristics inwinter-wheat/summer-maize rotation system in the North China Plain

Four tillage methods - conventional tillage without straw (CT), conventional tillage with straw incorporation (CTS), rotary tillage with straw incorporation (RTS) and no-tillage with straw mulch (NTS) - were used to study the effects of tillage on annual yield and water use efficiency in winter-wheat/summer-maize cultivation system in the North China Plain. Results showed that different tillage methods significantly influenced winter wheat yield and water use efficiency. Different tillage methods did not significantly influence yield and water use of summer maize, tillage with straw incorporation increased yield of summer maize. Although differences in winter wheat yield under RTS, CTS and CT were not significant, fewer effective panicles of winter wheat yield under NTS led to significantly lower yield, compared with other treatments. Compared with CT, NTS decreased annual yield by 5.13%, while RTS, CTS increased annual yield by 2.69% and 2.33%. The tillage methods had significant effects on soil water content in winter-wheat season, but had no impact on soil water content in summer-maize season. Also NTS improved soil water content and water storage in winter-wheat season. Compared with CT, NTS increased soil water storage by 39.07 mm and 26.65 mm in two consecutive years. In terms of crop water use, soil water accounted for the largest proportion of winter-wheat water use, followed by irrigation and precipitation. While precipitation accounted for the largest proportion of summer-maize water use, some precipitation contributed to soil water storage. NTS improved soil water storage in winter-wheat and also limited soil water use, implying that water use was lowest under NTS during winter-wheat season. Compared with CT, NTS saved 22.40 mm of soil water in winter-wheat season and NTS also had the lowest annual crop water use. There was lower winter-wheat yield under NTS, the annual water use efficiency was also lower than the other treatments. In terms of annual yield and water use efficiency, there was the need to increase winter-wheat yield under NTS thereby increasing annual production. This is critical because of the high water-saving capacity of NTS, which is a key crop cultivation issue in the North China Plain.