坡地生物炭垄沟集雨种植的系统效率和关键技术研究

Drought, water loss and soil erosion are main factors, which limited agricultural and husbandry production in semi-arid Loess Hilly areas. Traditional ridge-furrow rainwater harvesting produced much plastic residue, which causes white pollution. Biochar is a carbon-enriched substance produced by thermal decomposition of organic material in the absence of oxygen. Biochar has been demonstrated to restore soil fertility and crop production under many conditions, but less is known about the effects of its application on soil erosion and runoff control. Traditional ridge-furrow rainwater harvesting production was combined with biochar mulching in this project. 1) Runoff, sediment and crop yields were studied to determine the optimum biochar type, under ridge-furrow rainwater harvesting production with different biochar types (stalk biochar, cow dung biochar and Chinese traditional medicine residues biochar) mulching. 2) Runoff efficiency of standard ridges with different biochar mulching application (0×103、2×103、4×103、6×103 and 8×103 kg hm-2) was found after observing precipitation and runoff with the same receive areas at the same time. 3) Runoff storage efficiency, overall efficiency, soil water, soil nutrition, runoff, sediment and crop yields were studied to determine the optimum biochar mulching method and the optimum biochar mulching application, under ridge-furrow rainwater harvesting production with different biochar mulching methods (ridge mulching, ridge-furrow dual mulching, and furrow mulching) and different biochar mulching application (0×103、2×103、4×103、6×103 and 8×103 kg hm-2). Key technologies of ridge-furrow rainwater harvesting with biochar mulching were revealed under different precipitations in semi-arid areas combining experiments of runoff efficiency observation and ridge-furrow rainwater harvesting production with meteorological data.

干旱和水土流失是限制半干旱区坡地农牧业生产的关键因子。传统垄沟集雨种植产生地膜残留和污染。生物炭是有机物在限氧高温经热解生成的富碳物。研究证实生物炭能改良土壤和提高作物产量，但控制土壤侵蚀和径流研究较少。本项目结合垄沟集雨种植和生物炭覆盖技术，1)以土垄集雨种植为对照，研究坡地生物炭类型(秸秆炭、牛粪炭和药渣炭)垄沟集雨种植的径流、沉积和经济产量，确定适宜生物炭类型；2)观测生物炭施加量(0、2、4、6和8 ×103 kg hm-2) 标准坡地生物炭垄的径流，揭示生物炭集雨垄的径流效率；3)以普通膜垄集雨种植为对照，研究不同生物炭覆盖方式(垄覆盖、垄沟全面覆盖和沟覆盖)和不同生物炭施加量垄沟集雨种植的径流贮存效率、系统效率、土壤水分和养分、径流、沉积和经济产量等，明确适宜生物炭覆盖方式和生物炭施加量。结合径流、集雨种植和气象等数据，研究半干旱区不同降雨过程坡地生物炭垄沟集雨种植的关键技术。

1) 为寻求半干旱区垄沟集雨种植红豆草的最佳垄宽和适宜生物炭覆盖类型，采用随机区组设计，研究(1)不同垄宽(30、45和60 cm)和不同垄覆盖材料(土壤结皮、玉米秸秆炭土壤结皮和牛粪土壤结皮)集雨垄的径流效率；(2)不同垄宽和不同垄覆盖材料对土壤水分、温度、干草产量和WUE的影响。连续4a试验结果表明，土垄、玉米秸秆炭垄和牛粪炭垄的径流效率分别为29.1-33.1%、24.3-29.4%和21.3-25.9%。生物炭覆盖垄沟集雨种植增加垄上土壤温度和沟中土壤含水量，促进红豆草生长，玉米秸秆炭和牛粪炭覆盖垄沟集雨种植红豆草的最佳垄宽分别为43-49 和39-49 cm。.2)为寻求半干旱区垄沟集雨种植紫花苜蓿的最佳垄宽和适宜秸秆炭覆盖量，采用随机区组设计，研究(1)不同垄宽(30、45和60 cm)和不同秸秆炭覆盖量(0 × 104 (土垄)、3 × 104 (单倍秸秆炭垄)和6 × 104 kg hm-2(双倍秸秆炭垄) ) 集雨垄的径流效率；(2)不同垄宽和不同秸秆炭覆盖量对土壤水分、温度、干草产量和WUE的影响。连续4a试验结果表明，土垄、单倍秸秆炭垄和双倍秸秆炭垄的径流效率分别为29.1-33.1%、24.3-29.4%和23.2-28.4%。生物炭覆盖垄沟集雨种植增加垄上土壤温度和沟中土壤含水量，促进紫花苜蓿生长，单倍秸秆炭和双倍秸秆炭垄沟集雨种植紫花苜蓿的最佳垄宽分别为 32-40和26-37 cm，适宜秸秆炭覆盖量为3.4 × 104- 4.0 × 104 kg hm-2。.3)为寻求半干旱区坡地最佳施炭模式和耕作措施，采用裂区设计，施炭模式为主去，耕作措施为副区，研究施炭模式(施加秸秆炭和不施加秸秆炭)和耕作措施(开敞垄、打结垄和平作) 对土壤水分、温度、径流、泥沙流失、干草产量和WUE的影响。连续2a试验结果表明，与平作相比，开敞垄和打结垄的紫花苜蓿干草产量分别增加32.5-38.3%和23.5-24.8%，WUE分别提高13.2-14.3%和15.7-16.3%，而径流量分别降低19.8-37.7%和33.5-55.0%，泥沙流失量分别降低65.2-75.5%和81.6-87.6%。施加秸秆炭的干草产量、WUE、径流量和泥沙流失量分别是不施加秸秆炭的1.43、1.35、0.43和0.67倍。坡地施加秸秆炭打结垄沟集雨种植具有较好保水和增产效果。