黑土区施加生物炭对土壤综合肥力与大豆生长的影响

Effects of Applying Biochar on Soil Comprehensive Fertility and Soybean Growth in Black Soil Area

为探明黑土区施加生物炭对土壤持水性能、土壤养分以及大豆生长的影响,以东北黑土区3°坡耕地田间径流小区为研究对象,进行为期4年的观测。按照生物炭施加量,2015年共设置C0(0 t/hm^2)、C25(25 t/hm^2)、C50(50 t/hm^2)、C75(75 t/hm^2)、C100(100 t/hm^2)5个处理,2016—2018年分别连续施加等量的生物炭。结果表明:连续4年,0~60 cm土层土壤储水量随施炭量的增加呈先增大、后减小的趋势,而对60~100 cm土层土壤储水量影响不显著;连续4年,饱和含水率随施炭量的增加呈逐渐增大的趋势;2015年田间持水率、凋萎系数随施炭量的增加呈逐渐增大趋势,2016—2018年呈先增加、后减小趋势;连续4年,施加生物炭提高了大豆各生育阶段的株高和叶面积,同期相对较优处理分别为C75、C50、C50、C25;连续4年,大豆冠层覆盖度与施炭量呈抛物线变化(R^2均在0.89以上,P<0.01),连续施加2年的C50处理各生育期提高量最大,与C0相比提高了81.4%、36.7%、31.5%和39.6%;连续4年,土壤pH值和有机质、速效钾含量随施炭量的增加呈逐渐升高趋势,碱解氮、有效磷含量呈先升高、后降低趋势,相对较优处理为C50、C50、C25、C25。采用改进的内梅罗指数模型计算的土壤综合肥力指数与产量呈正相关(R^2=0.8615,P=0.0012,RMSE为0.75),土壤综合肥力水平最高的生物炭施用模式为连续2年施加50 t/hm^2的生物炭。

In order to explore the effects of biochar on soil water retention,soil nutrients and soybean growth in the black soil area,a four-year observation experiment was conducted on the runoff plot of 3°sloping farmland in the northeast black soil area.In 2015,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 according to the amount of biochar applied.For each treatment,the same amount of biochar was continuously applied in 2016,2017 and 2018.The results showed that the soil water storage in the 0~60 cm soil layer was increased and then decreased with the increase of carbon loading for four consecutive years,but the effect on water storage capacity in 60~100 cm soil layer was not significant.The saturated water content was increased gradually with the increase of carbon application.In 2015,the water holding capacity and the coefficient of wilting was increased gradually with the increase of carbon application.The growth rate was decreased first and then decreased from 2016 to 2018;applying biochar for four consecutive years increased the plant height and leaf area of soybean growth stages.The optimal treatments were C75,C50,C50 and C25 respectively;the canopy coverage and charcoal content of the four consecutive years showed a parabola change(R^2>0.89,P<0.01).The continuous increase of C50 treatment for two years had the largest increase in each growth period,which was 81.4%,36.7%,31.5%and 39.6%higher than that of C0.The soil pH value,organic matter and available potassium content were increased gradually with the increase of carbon application for four consecutive years.The alkali nitrogen and available phosphorus were increased first and then decreased.The relatively better four-year treatments were C50,C50,C25 and C25.The comprehensive fertility index calculated by the improved Nemerow index model was positively correlated with yield(R^2=0.8615,P=0.0012,RMSE was 0.75).The biochar application mode with the highest level of soil comprehensive fertility was summarized,that was,50 t/hm^2 of biochar applied for two consecutive years.The research result can provide a theoretical basis for the application of biochar in the black soil region.