耕作方法对黄土高原旱作玉米产量和土壤水温特性的影响

Effect of different tillage practice on rain-fed maize yield and soil water/temperature characteristics in the Loess Plateau

  • 摘要: 全膜双垄沟播是黄土高原旱作玉米主要生产技术, 但此技术的土壤耕作主要依赖传统耕作和旋耕, 在形成犁底层的同时造成耕层变浅, 影响玉米生长、产量形成以及土壤健康。本文以打破犁底层、改善土壤结构、提高黄土高原旱地玉米(Zea may L.)产量和有限降水资源利用效率为目标, 布设大田定位试验, 比较研究了深松耕、免耕、旋耕和传统耕作对旱地全膜双垄沟播玉米土壤水分、温度、土壤容重、产量以及水分利用效率的影响。结果表明: 全膜双垄覆盖条件下, 深松耕和免耕较旋耕和传统翻耕能有效增加0~30 cm土壤贮水量, 其0~30 cm土层土壤含水量较翻耕、旋耕分别增加50.0%、43.7%和14.8%、10.3%; 深松耕能有效降低5~30 cm土层土壤容重, 其5~10 cm和10~30 cm土层土壤容重, 深松耕较传统耕作分别降低10.9%和12.9%, 随着土层的加深, 深松耕、免耕的土壤容重呈降低趋势, 旋耕和传统翻耕呈增大趋势; 深松耕在苗期、拔节—抽雄期较传统翻耕分别具有明显的增温和降温作用, 有利于玉米生长和产量提高; 2 个平水年, 深松耕处理的玉米生物产量、籽粒产量和水分利用效率分别较传统翻耕增加6.1%~5.6%、18.6%~28.8%和28.1%~32.9%, 具有明显的增产和提高水分利用效率的作用。因此, 在黄土高原半干旱区同等降雨条件下, 深松耕能有效增加全膜双垄沟播玉米的土壤贮水量, 改善土壤结构, 协调水温关系, 有利于增产和提高水分利用效率, 是全膜双垄沟播玉米一项理想的土壤耕作方法。

     

    Abstract: Complete film mulch of alternating narrow and wide ridges with furrow planting (CMRF) significantly increases maize yield and water use efficiency (WUE). It has been the dominant mode of maize production in the semiarid Loess Plateau region. However, due to single tillage methods (e.g., conventional tillage and rotary tillage) continuous applied in the CMRF system, it was apparent that soil water infiltration was affected by the soil plow pan. This has caused the top soil layer shallow, which adversely impacted maize growth, grain yield and soil health. In order to eliminate the plow pan, improve soil structure, increase utilization of the limited rainfall, and enhance crop productivity, a field experiment was conducted at Dingxi in the semiarid Loess Plateau region of northwest China in 2012 and 2013. The study determined the effects of different tillage methods on soil water content, soil water storage, soil bulk density, soil temperature, and water use efficiency (WUE) and grain yield of CMRF system in the rain-fed semiarid environment of the Loess Plateau. Maize was grown under four tillage modes — conventional tillage (T1), no-tillage (T2), rotary tillage (T3) and sub-soiling (T4). The results showed that soil water storage in the 030 cm soil depth increased significantly under sub-soiling and no-tillage. Compared with conventional tillage, and rotary tillage, sub-soiling and not-tillage increased 030 cm depth soil water content by 50.0% and 43.7%, and 14.8% and 10.3%, respectively. Soil bulk density in the 510 cm and 1030 cm soil depths were 10.9% and 12.9% lower under sub-soiling than conventional tillage, respectively. Under sub-soiling and no-tillage conditions, soil bulk density increased with increasing soil depth. On the contrary, soil bulk density decreased with increasing soil depth under rotary tillage and conventional tillage. Soil temperature was higher at seedling stage and lower at jointing-to-tasselling stage under sub-soiling than under conventional tillage. This was critical for improving grain yield, biomass and water use efficiency of maize. In 2012 and 2013, two normal-precipitation years, sub-soiling increased by 5.6%6.1% in maize biomass, by 18.6%28.8% in grain yield and by 28.1%32.9% in water use efficiency, compared with conventional tillage. The study showed that under the same rainfall conditions, sub-soiling in combination with CMRF was the most promising agronomic practice in terms of improving soil water storage and structure. It also coordinated relationship between soil water and temperature, and increased maize yield and water use efficiency in the Loess Plateau of China.

     

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