坡地打结垄沟集雨对水土流失、紫花苜蓿干草产量和水分利用效率的影响

为寻求半干旱区控制水土流失和提高降水资源利用率的最佳坡地垄沟集雨种植方式,以传统平作为对照,在坡度5°和10°的坡地布置大田试验,研究打结方式(无打结垄和打结垄)对土壤贮水量、小区径流效率、径流量、泥沙流失量、紫花苜蓿干草产量和水分利用效率(WUE)的影响。结果表明:在坡度5°时,与平作相比,无打结垄和打结垄的紫花苜蓿全生育期土壤贮水量分别增加9.3,15.0mm,紫花苜蓿实际干草产量分别提高20.4%,8.9%,WUE分别提高4.78,4.58kg/(hm2·mm),而径流量分别降低21.9%,41.2%,泥沙流失量分别降低80.8%,83.3%。在坡度10°时,与平作相比,无打结垄和打结垄的紫花苜蓿全生育期土壤贮水量分别增加11.2,16.2mm,紫花苜蓿实际干草产量分别提高22.4%,9.0%,WUE分别提高4.89,4.06kg/(hm2·mm),而径流量分别降低24.8%,36.4%,泥沙流失量分别降低74.5%,82.0%。采用平均径流法,坡度5°时,平作、无打结垄和打结垄的小区径流效率分别为11.6%,9.2%,6.7%;坡度10°时,平作、无打结垄和打结垄的小区径流效率分别为14.1%,10.0%,7.8%。就紫花苜蓿全生育期平均值而言,坡度5°的平均土壤贮水量比坡度10°增加4.3mm,坡度5°的净干草产量、实际干草产量和WUE与坡度10°相差不明显。坡度10°的径流量、泥沙流失量和小区径流效率均是坡度5°的1.2倍。无打结垄和打结垄集雨种植具有较好水土保持和增产效果,其中无打结垄增产效果最为明显,打结垄水土保持效果最为明显。

Effects of Tied-ridging Rainwater Harvesting on Soil Erosion, Alfalfa Fodder Yield and Water Use Efficiency on Slope Lands

In order to seek the optimum tied-ridging tillage system with good controlling on soil erosion, and high utilization of precipitation in semi-arid area, a field experiment with a randomized complete block design was conducted on two slopes (5° and 10°) during alfalfa growing season. The experiment was designed to investigate the effects of different tillage systems (ridging without ties and tied-ridging) on soil water storage, plot runoff efficiency, runoff, sediment loss, alfalfa fodder yield and water use efficiency (WUE), and traditional planting (TP) was taken as control. On the 5°slope, compared with TP, average soil water storage, alfalfa fodder yields and the WUE for ridging without ties increased by 9.3 mm, 20.4% and 4.78 kg/(hm2·mm), respectively. The corresponding parameters for tied-ridging increased 15.0 mm, 8.9 % and 4.58 kg/(hm2·mm), respectively. Runoff and sediment loss on the same slope for ridging without ties decreased by 21.9% and 80.8%, respectively, while these two parameters of tied-ridging decreased by 41.2% and 83.3%. On the 10° slope, compared with TP, average soil water storages, alfalfa fodder yields and the WUE for ridging without ties and tied-ridging increased by 11.2 and 16.2 mm, 22.4% and 9.0%, 4.89 and 4.06 kg/(hm2·mm), respectively, while the runoffs and sediment losses of these two tillage systems ridging decreased by 24.8% and 36.4%, 74.5% and 82.0%, respectively. Average plot runoff efficiencies of TP, ridging without ties and tied-ridging were 11.6%~14.1%, 9.2%~10.0% and 6.7%~7.8%, respectively. Soil water storage in 5° slope increased by 4.3 mm compared with slope of 10°. The differences of net fodder yield, actual fodder yield and WUE between 5° and 10° slopes were not distinct. The runoff, sediment loss and plot runoff efficiency of 10° slope were 1.2 times greater than those of 5° slope. Ridge-furrow rainwater harvesting was good on water and soil conservation, and fodder yield increasing. Tied-ridging was particularly effective for water and soil conservation, while ridging without ties was particularly effective for increasing of fodder yield.