The black soil region in Northeast China is rich in soil fertility,good in soil properties,and suitable for crop growth.However,the problem of soil erosion in sloping farmland seriously threatened the regional ecological environment and national food security.To discover the influences of the optimal amount and duration of biochar supply on water saving and yield increasing in slopping farmland of the region,the two years experiments were conducted based on runoff plot in 2015 and 2016.Five treatments were set according to different amounts of biochar,which were 0 t/hm2 (C0),25 t/hm2 (C25),50 t/hm2 (C50),75 t/hm2 (C75) and 100 t/hm2 (C100),and the same amount of biochar for each treatment was supplied continuously in the next year.The results showed that biochar made the soil bulk density decreased,and the soil porosity and organic carbon density were increased sharply with the increase of biochar in two years.The field capacity was increased with the increase of biochar in 2015 while which was first increased and then decreased in 2016,and the best one was the treatment of C50.At the same time,the three-phase and generalized soil structure index (GSSI) were the most reasonable in C50 compared with others.The annual runoff in three degrees sloping farmland both were decreased in the two experiment years,and the annual runoff coefficient was decreased most,which was in the treatment of C75 (by 15.44％) in 2015 and C50 (by 17.27％) in 2016.The addition of biochar also could increase the soil water accumulation amount and decrease the rate and magnitude with time after rainfall.The highest yield of soybean was respectively C75 (27.16％) in 2015 and C50 (28.17％) in 2016.Compared the results in 2015 and 2016,the water use efficiency of soybean was increased by 27.67％ with 50 t/hm2 biochar supply for two years compared with the control treatment,and the effect of water saving and yield increasing of the treatment was the best one.%东北黑土区土壤肥沃、性状优良、适宜作物生长,然而大面积坡耕地的水土流失问题严重威胁着区域生态环境和国家粮食安全.为探明施加生物炭对该区域坡耕地的节水增产效应,以及最优施加量与施加年限,基于田间径流小区进行为期两年的观测试验.2015年,试验根据生物炭施加量设置为C0(0 t/hm2)、C25(25 t/hm2)、C50(50t/hm2)、C75(75t/hm2)和C100(100 t/hm2)5个处理;2016年,各处理分别连续施加等量生物炭.试验结果表明:施加两年生物炭均降低了土壤容重、提高了孔隙度和有机碳密度,且随施加量的增加效果越显著;2015年实测田间持水量随生物炭施加量呈上升的趋势,2016年则呈先升后降的趋势,上升至C50处理达到最佳;2016年C50处理土壤三相比较合理,广义土壤结构指数(GSSI)高于其他处理;连续两年施加生物炭均减少了3°坡耕地的年径流量,各年份年径流系数降低最多的分别为C75(15.44％)和C50(17.27％)处理.适量生物炭也可增加单次降雨后雨水蓄积量和其随时间下降的速率和幅度;2015年和2016年大豆产量最高的处理分别是C75和C50,增产率分别为27.16％和28.17％.比较2015年和2016年试验结果,连续两年施加50t/hm2生物炭时,大豆水分利用效率较对照处理增幅最高,为27.67％,节水增产效果最佳.
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