覆膜、沟垄作对旱作农田玉米产量和水分利用的叠加效应

为了揭示黄土高原半干旱区玉米(Zea mays L.)种植中覆膜、沟垄作的增产作用和水分利用特征,布设大田定位试验,包括全覆膜沟垄作、全覆膜平作、半覆膜平作和不覆膜平作4个处理。结果发现,连续3个平水年中,全膜沟垄作集成了全覆膜与沟垄作的优点,产生明显的叠加效应,较半膜平作分别增产2282.9、2460.2和2765.5 kg hm~(–2),增产率为32.3%、49.8%和46.5%。其中,全覆膜的贡献分别为59.3%、90.3%和20.9%,沟垄作的贡献分别为40.7%、9.7%和79.1%。叠加效应中全覆膜与沟垄作对产量的贡献呈此消彼长态势,连作前两年,全覆膜的作用大于沟垄作,连作第3年,沟垄作的作用大于全覆膜。玉米的水分利用效率,全膜沟垄作较半膜平作的增幅为10.6%~25.2%。在同等降水条件下,全覆膜沟垄作、全覆膜平作处理播前土壤贮水量较不覆膜平作增幅分别达6.3%~15.1%和3.5%~11.5%。收获期土壤贮水量明显低于不覆膜平作,降幅达6.0%~12.9%和4.7%~7.5%。随着连作年限的增长,土壤贮水量呈递减趋势,连作第2、第3年收获期全覆膜沟垄作、全覆膜平作较连作开始土壤贮水量分别降低37.1%、44.0%和35.5%、40.9%,连作第2年全覆膜沟垄作在50~200 cm出现干燥化现象,第3年各处理30~200 cm土层均出现干燥化现象。综上所述,全覆膜沟垄作具有明显的增产和提高水分利用效率的作用,但其较高的产量以高耗水为代价,在连续低降水条件下,3年玉米连作会导致土壤干燥化,存在生态安全风险。

Superimposition Effect of Film-mulching and Furrow Ridging Culture on Maize Grain Yield and WUE in Loess Plateau

A three-year continuous maize cropping study was conducted to compare the effect of different planting treatments on water use efficiency (WUE) and grain yield of maize in a semi-arid environment in the western Loess Plateau of China. The experiment was arranged in a randomized block design with three replicates. The treatments included flat-planting without mulching (NFM), flat-planting with half plastic film mulching (HFM), flat-planting with complete plastic film mulching (CFM) and furrow-planting with plastic film completely mulched narrow and wide alternative ridges (CFRM). CFRM treatment had a superimposition effect, increasing maize grain yield by 2282.9, 2460.2, and 2765.5 kg ha^-1, with the increasing ratio of 32.3%, 49.8%, and 46.5%, compared with HFM treatment in the three continuous cropping years. In addition, the contribution rate to grain yield complete film mulching was 59.3%, 90.3%, and 20.9%, and by furrow-ridging culture was 40.7%, 9.7%, and 79.1%, respectively. The complete film mulching had greater contribution to yield than ridging and furrowing culture in the first and second years, and vice versa in the third year. The water use efficiency was the highest in CFRM treatment throughout the three years, with an incremental from 10.6% to 25.2%, in comparison to HFM. Under the same precipitation conditions, CFRM and CFM treatments had higher soil water storage before maize sowing than NFM, increasing from 6.3% to 15.1% and from 3.5% to 11.5%, respectively. However, CFRM and CFM treatments had lower soil water storage than NFM after maize harvest, with a decrease from 6.0% to 12.9% and from 4.7% to 12.9% in the second and third years, respectively. The soil water storage declined with continuous cropping of maize at harvesting stage in the second and third years, showing decrease of 37.1% and 44.0% for Soil water storage of CFRM, 35.5% and 37.1% for CFM, respectively. In particular, the soil desiccation phenomenon was appeared in 50 to 200 cm soil layer of CFRM treatment in the second year, and other treatments in the third year. In conclusion, CFRM is the best option for efficient water use and increasing grain yield, which is attributed to higher water demand, that leads to soil desiccation.