多种有机物料混施对苹果幼苗生长、氮素利用及土壤特性的影响

以"M9T337"苹果幼苗为试材,利用~(15)N同位素示踪技术,研究了等氮量投入下,不同有机物料单施及混施对苹果幼苗生长、~(15)N吸收利用及土壤特性的影响。试验设置CK(只施用化学肥料,不施有机物料)、S(秸秆)、B(生物炭)、F(牛粪)、SB(1/2秸秆+1/2生物炭)、SF(1/2秸秆+1/2牛粪)、FB(1/2牛粪+1/2生物炭)、SFB(1/3秸秆+1/3牛粪+1/3生物炭)8个处理。结果表明:施用有机物料可以促进苹果幼苗的生长,其中SFB处理植株鲜重、株高、茎粗、叶面积、根系活力达到最优,显著高于CK和单施有机物料的处理。添加有机物料能降低土壤容重、增加孔隙度、提高土壤含水量,其中施用生物炭的处理土壤容重降幅较大、孔隙度较高。处理期间,有机物料混合施用的处理土壤矿化氮含量、土壤酶活性及微生物数量均优于有机物料单独施用的处理。与CK和单施有机物料的处理相比,有机物料混合施用显著提高了苹果幼苗~(15)N利用率和土壤~(15)N残留率,降低了~(15)N损失率,其中3种有机物料混施效果最好。综合分析可知,有机物料能促进苹果幼苗生长,改良土壤性质,促进植株对~(15)N的吸收利用,其中牛粪、秸秆和生物炭混合施用的处理(SFB处理)效果最佳。研究结果以期为有机物料在苹果园土壤质量提升和化肥减施增效中的应用提供依据。

Effects of Mixtures of Different Organic Materials on Apple Seedling Growth, Nitrogen Utilization and Soil Properties

M9T337 apple seedlings were used to study the effects of different organic materials and their combination on plant growth, nitrogen utilization and soil properties by using the ¹⁵N isotope tracer technique. There were 8 treatments:CK (chemical fertilizer), S (straw), B (biochar), F (cow dung), SB (1/2 straw + 1/2 biochar), SF (1/2 straw + 1/2 cow dung), FB (1/2 cow dung + 1/2 biochar), SFB (1/3 straw + 1/3 cow dung + 1/3 biochar). The results showed that the application of organic materials promoted the growth of apple seedlings, and SFB treatment had the best fresh weight, height, stem diameter, leaf area and root activity, which were significantly higher than CK and the treatment of single organic materials. The application of organic materials decreased soil bulk density, increased soil total porosity and soil moisture content. The soil bulk density and total porosity under the combined application of biochar were better. During the treatment period, the soil mineralized nitrogen contents, the soil enzymes activities and microbial population under the treatments with mixed organic materials were better than those under the treatments with organic materials alone. Compared with CK and the single organic materials, the combined application of organic materials significantly improved the ¹⁵N utilization rate of apple seedlings and ¹⁵N residual rate in soils, reduced the ¹⁵N loss rate and the SFB treatment had the best effect. According to the comprehensive analysis, the application of different organic materials could promote the growth of apple seedlings, improve soil properties, and improve the absorption and utilization of ¹⁵N, among which the combined application of cow dung, straw and biochar (SFB treatment) had the best effect. These findings could provide a basis for the application of organic materials in apple orchard for the soil quality improvement and fertilizer reduction and efficiency.