生物炭及炭基氮肥对土壤持水性能影响的研究

Effects of Biochar and Biochar-based Nitrogen Fertilizer on Soil Water-holding Capacity

为了探明生物炭及生物炭基氮肥对土壤水分特征的影响,采用实验室土柱入渗、水分特征曲线法测定了混入不同量生物炭材料、生物炭基氮肥土样的水分入渗率、水分吸持力等有关数值。结果表明:随着生物炭材料、生物炭基氮肥混入量的增多,2种土壤垂直土柱水分入渗率均逐渐减小;在水势相同情况下,与对照相比,混入量越大,土壤可保持的水分越多,但这种增加效应是有限度的,超过一定混入量(80t/hm2)反而会降低土壤持水量;不同生物炭基氮肥对同一土壤及同一生物炭基氮肥对不同质地土壤持水容量的影响均存在差异。因此,在田间实际应用中,生物炭基氮肥对土壤水分特征的影响取决于生物炭基肥料的性质或特征、施用量及土壤质地等因素。

Soil water characteristics including soil water infiltration rate,soil water suctions and water-holding capacity of soil samples incorporated with varied dosage of biochar materials and biochar-based nitrogenous fertilizer were tested and estimated by water infiltration of soil column and soil water characteristic curve in laboratory in this article in order to understand the effects of biochar and biochar-based nitrogenous fertilizers on the soil water characteristics.The experimental results indicated that：the water infiltration rate of two vertical soils column decreased with the increase of the addition rate of biochar materials and biochar-based nitrogenous fertilizer to soils.In comparison with the control treatment,under the same water potential condition,the more fertilizers incorporated into soils,the more water retained by soils,however,soil water-holding capacity decreased when the rate of biochar or biochar-based nitrogenous fertilizer added to soils exceeds maximum（80 t/hm 2）（inflexion）.The soil water-holding capacity varied from the types of biochar-based nitrogenous fertilizer to the textures of soils.Therefore,in practical field,the impact of biochar-based nitrogenous fertilizer on the characteristics of soil water depended on the properties and application rate of biochar-based nitrogenous fertilizer and soil texture.