不同草粮轮作方式对退化苜蓿草地水分恢复的影响

    Effects of different alfalfa-crop rotation patterns on water recovery of degradation alfalfa grassland

    • 摘要: 2003-2005年在黄土高原宁南旱区10年生退化苜蓿草地上进行了连续3 a不同作物组合方式的轮作试验,轮作作物为春小麦、马铃薯和谷子,为研究比较不同轮作方式对退化苜蓿土壤水分的恢复状况和作物产量效益,优化出较为合理的草粮轮作模式。试验结果表明,轮作地0~60 cm土层土壤易受降水和地面蒸发影响,60~120 cm土层土壤水分主要被轮作作物利用,而120~200 cm土层土壤水分相对较为稳定,受降水和地面蒸发影响很小,并随轮作年限的增加,基本上表现出不断恢复趋势。通过草粮轮作可以增加苜蓿地120~200 cm土层土壤水分,且显著高于撂荒地和对照苜蓿地,同时可获得一定作物产量。相对于其他轮作方式而言,马铃薯-马铃薯-春小麦(PPW)轮作处理能够充分利用有限的降水资源,对土壤水分具有较好的恢复作用,其作物总产量和水分利用效率均较高,分别为5214.5 kg/hm2和9.38 kg/(hm2·mm-1),与轮作前苜蓿地相比,120~200 cm土层土壤水分净恢复量为24.73 mm。

       

      Abstract: Experiments were carried out in the drought areas of southern Ningxia Hui Autonomous Region on the loess plateau during from 2003 to 2005, in which three kinds of crops including spring wheat, potato and millet were rotated in the form of combination on the 10-year-old degraded alfalfa grassland. The purposes are to study and compare the soil moisture restoration conditions and crop production effectiveness between different rotations, thus approach more reasonable alfalfa rotation patterns. The results showed that, rotation in 0-60 cm soil layer was vulnerable to the impact of precipitation and surface evaporation, moisture in 60-120 cm soil was mainly consumed by rotation crops, while moisture in 120-200 cm was stable relatively and rarely influenced by precipitation and surface evaporation, and there was a trend of continuous restoration in it with the increasing of rotation year. The moisture in 120-200 cm soil could be improved by alfalfa-crop rotation. And it was significantly higher than that of abandoned land and grassland (CK), and could obtain certain crop yields meanwhile. Compared with other alfalfa-crop rotation patterns, potato- potato- wheat rotation pattern (PPW) has better restoration role on grassland moisture and ability to make use of limited precipitation. Total yields and water use efficiency (WUE) of rotation crops with PPW pattern were both relatively higher than others, i.e., 5214.5 kg/hm2 and 9.38 kg/(hm2·mm), respectively. Compared with alfalfa farmland before crop rotation, the net moisture recovery amount of PPW rotation pattern was 24.73 mm in 120-200 cm soil layer.

       

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