摘要:为探索半干旱黄土高原区垄沟集雨种植的可持续性，寻求垄沟集雨种植红豆草的适宜生物炭覆盖类型和最佳垄宽，采用随机区组大田试验，以传统平作为对照，研究不同集雨垄覆盖材料[土壤结皮（土垄）、玉米秸秆炭土壤结皮（玉米秸秆垄）和牛粪炭土壤结皮（牛粪炭垄）]和不同垄宽（30 cm、45 cm和60 cm，沟宽均为60 cm）对径流系数、土壤水热、红豆草干草产量和水分利用效率的影响。结果表明：土垄、玉米秸秆炭垄和牛粪炭垄的平均径流系数分别为29.7%、26.2%和25.1%。垄沟集雨种植增加根系层土壤含水量和垄上表层土壤温度，缓和沟中表层土壤温度极值，尤其生物炭覆盖垄沟集雨种植。与传统平作相比，土垄、玉米秸秆炭垄和牛粪炭垄的土壤含水量分别增加25.1mm、24.7 mm和19.4 mm，垄上表层土壤温度分别增加1.4℃、2.0℃和2.0℃。同一覆盖材料下，集雨垄径流系数、土壤贮水量和表层土壤温度均随垄宽增加而增加。与传统平作相比，土垄显著降低实际干草产量，玉米秸秆炭垄和牛粪炭垄显著增加实际干草产量，垄宽30 cm、45 cm和60 cm土垄的干草产量分别减少6.5%、12.1%和13.8%，玉米秸秆炭垄的干草产量分别增加19.7%、24.4%和22.5%，牛粪炭垄的干草产量分别增加8.0%、8.9%和6.8%。玉米秸秆炭和牛粪炭覆盖种植显著提高水分利用效率。与传统平作相比，玉米秸秆炭垄和牛粪炭垄的水分利用效率分别提高6.8~9.7 kg·hm-2·mm-1和4.4~4.8kg·hm-2·mm-1。玉米秸秆炭垄的实际干草产量和水分利用效率显著高于牛粪炭垄；同一覆盖材料下，不同垄宽对实际干草产量和水分利用效率的影响不显著。线性回归分析表明，当玉米秸秆炭垄宽49 cm（沟宽为60 cm）与牛粪炭垄宽为41 cm（沟宽为60 cm）时，红豆草的实际干草产量均达到最大值。因此，在半干旱地区，生物炭覆盖垄沟集雨种植红豆草具有较好的增产效益，尤其秸秆生物炭覆盖种植。
关键词:垄沟集雨/
红豆草/
生物炭覆盖/
土壤结皮/
径流系数/
干草产量/
水分利用效率
Abstract:Ridge-furrow rainwater harvesting (RFRH) with mulch offers farmers a means to address drought, water loss, and soil erosion in arid and semiarid regions. The purpose of this study was to determine a suitable biochar type and optimum ridge width for sainfoin (Onobrychis viciaefolia Scop.) production using the RFRH system with biochar application in the semi-arid regions in China. A field experiment with a completely random block design was conducted during the 2017 sainfoin growing season to (1) estimate runoff coefficient of the RFRH system with three ridge widths (30, 45, and 60 cm) and the same narrow width (60 cm), and mulched with three materials (soil crust, maize straw biochar-soil crust, and cow dung biochar-soil crust) and (2) assess the effects of three ridge widths and three mulching materials on soil water storage, topsoil temperature, as well as fodder yield and water use efficiency (WUE) of the RFRH system planted with sainfoin, and a traditional flat planting (FP) system was used as the control. The results showed that the predicted runoff coefficient for ridge-furrow planting with the ridges mulched with manually compacted soil crust, maize straw biochar-soil crust, and cow dung biochar-soil crust (MCS, MSB, and CMB, respectively) was 29.7%, 26.2%, and 25.1%, respectively, whereas the threshold rainfall to produce runoff was 4.2, 4.6, and 5.1 mm, respectively. The runoff coefficient of ridge, soil water storage, and soil temperature increased with increase in ridge width using the same mulching materials. The RFRH system, especially MSB and CMB treatments, increased soil water storage of the root layer and ridge topsoil (0-25 cm) temperature, and decreased the rate of change of furrow top soil (0-25 cm) temperature. Compared with that of FP, the mean soil water storage (0-200 cm) increased by 25.1, 24.7, and 19.4 mm, on an average, under MCS, MSB, and CMB throughout the sainfoin growth period, respectively; whereas the topsoil temperature increased by 1.4℃, 2.0℃, and 2.0℃, respectively, on an average. For the same mulching material, soil water storage and topsoil temperature increased with increase in ridge width. MCS significantly decreased the actual fodder yield of sainfoin, but MSB and CMB significantly increased the actual fodder yield. Compared with that under FP treatment, the actual fodder yield under MCS with 30, 45, and 60 cm ridge width decreased by 6.5%, 12.1%, and 13.8%, respectively. Whereas, the actual fodder yield under MSB with 30, 45, and 60 cm ridge width increased by 19.7%, 24.4%, and 22.5%, and that under CMB increased by 8.0%, 8.9%, and 6.8%, respectively. MSB and CMB significantly increased WUE of sainfoin. Compared with FP, MSB and CMB increased WUE by 6.8-9.7 and 4.4-4.8 kg·hm-2·mm-1, respectively. The ridge width had no significant effect on the actual fodder yield and WUE with the same mulching materials. When the ridge width (furrow width was 60 cm) was 49 cm for MSB and 41 cm for CMB, the forage yield reached the maximum. The actual fodder yield and WUE of sainfoin under MSB were significantly higher than those under CMB, which were significantly higher than those under MCS. In summary, RFRH with biochar-soil crust mulching has beneficial effects on soil water storage and yield of sainfoin in the region, especially ridges with maize straw biochar-soil crust mulching.
Key words:Ridge-furrow rainwater harvesting/
Sainfoin (Onobrychis viciaefolia Scop.)/
Biochar mulching/
Soil crust/
Runoff coefficient/
Fodder yield/
Water use efficiency
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