连年施加生物炭对黑土区土壤改良与玉米产量的影响

Effects of Successive Application of Biochar on Soil Improvement and Maize Yield of Black Soil Region

为研究连年施加生物炭对黑土区坡耕地的土壤结构、持水性能、玉米产量及可持续性的影响,从2015年开始,在黑土区3°坡耕地径流小区内,将玉米作为试验作物连续进行4年生物炭效应试验。共设置C0(0 t/hm^(2))、C25(25 t/hm^(2))、C50(50 t/hm^(2))、C75(75 t/hm^(2))和C100(100 t/hm^(2))5种生物炭的施用量处理。结果表明:4年中土壤容重随生物炭的增加有减小的倾向,孔隙度有逐渐增加的倾向;适量生物炭可有效降低土壤固相比例,提高气相和液相比例,除2015年外,连续3年广义土壤结构指数(GSSI)随施炭量的增加先增大后减小,土壤三相结构距离指数(STPSD)随施炭量的增加先减小后增大,均在第3年C50处理达到最优(99.96、0.63),同时土壤三相比偏离值R最小(1.03),三相比最接近理想状态;连续4年大于0.25 mm团聚体含量R_(0.25)、平均质量直径(MWD)和几何平均直径(GMD)随着生物炭的增加有先增加后减小的倾向;连续3年加入50 t/hm^(2)生物炭提高土壤稳定性的效果最好;连续4年饱和含水率与施炭量呈正相关;除2015年外,田间持水率随施炭量的增加先增加后减小,分别在C100、C50、C50和C25处达最优,在2018年C25处为峰值37.33%;土壤有效含水率与田间持水率的变化规律相同。玉米各生育期0~60 cm土层土壤储水量呈先升高后降低倾向;60~100 cm土层土壤储水量与施炭量呈负相关;玉米产量可持续性指数(SYI)在C50处达到最大(0.954),变异系数(CV)在C100处理处最低(0.022);逐年施加50 t/hm^(2)生物炭对促进玉米产量稳定性与可持续性效果最明显。

In order to study the effects of biochar application on soil structure,water holding capacity,maize yield and sustainability of sloping farmland in black soil area,four consecutive years of biochar effect experiments were carried out in the runoff plot of 3°sloping farmland in black soil area from 2015.A total of five biochar application rates C0(0 t/hm^(2)),C25(25 t/hm^(2)),C50(50 t/hm^(2)),C75(75 t/hm^(2))and C100(100 t/hm^(2))were set.The results showed that soil bulk density was decreased with the increase of biochar in the four years,and porosity was increased gradually.Appropriate amount of biochar can effectively reduce the proportion of soil solid phase and improve the proportion of gas phase and liquid phase.In addition to 2015,the generalized soil structure index(GSSI)was increased first and then decreased with the increase of biochar application rate for three consecutive years,and the three-phase structure distance index(STPSD)was decreased first and then increased with the increase of biochar application rate,reaching the optimal values(99.96,0.63)in the third year of C50 treatment.At the same time,the soil three-phase ratio R was the smallest(1.03),and the three-phase ratio was the closest to the ideal state.For four consecutive years,the aggregate content R_(0.25),mean mass diameter(MWD)and geometric mean diameter(GMD)were increased first and then decreased with the increase of biochar application rate.Adding 50 t/hm^(2) biochar for three consecutive years had the best effect on improving soil stability.The saturated moisture content was positively correlated with carbon application rate for four consecutive years.In addition to 2015,the field water holding rate was increased first and then decreased with the increase of carbon application rate,and reached the optimal treatment at C100,C50,C50 and C25,respectively.The peak value was 37.33%at C25 in 2018.The change rule of soil effective moisture content and field water holding capacity was the same.Soil water storage in 0~60 cm soil layer of maize at different growth stages was increased first and then decreased.Soil water storage in 60~100 cm soil layer was negatively correlated with carbon application rate.The maize yield sustainability index(SYI)reached the maximum at C50(0.954),and the coefficient of variation(CV)was the lowest at C100(0.022).Annual application of 50 t/hm^(2) biochar to promote maize yield stability and sustainability effect was the most obvious.