玉米秸秆还田配施氮肥对不同土层土壤理化性质的影响

Effects of Corn Straw Return Plus Nitrogen Fertilizers on the Physic-chemical Properties in Different Soil Layers

基于11 a肥料定位试验,解析玉米秸秆还田配施氮肥模式下不同土层的土壤理化性质变化,为作物高产栽培的田间养分管理提供科学理论和实践依据。试验以玉米秸秆还田、秸秆不还田为主因素,5个氮肥处理水平0(CK)、90(N1)、180(N2)、270(N3)、360(N4)kg·hm^(-2)为辅因素进行裂区设计,测定了0~20 cm和20~40 cm土层的土壤酸碱度(pH)、脲酶、酸性磷酸酶和蔗糖酶活性以及碱解氮、速效钾和有效磷的含量。结果表明,与CK相比,玉米秸秆还田配施氮肥对0~20 cm土层土壤的理化性质影响较大,而对20~40 cm土层土壤的理化性质影响较小。过量施用氮肥会加剧土壤酸化,而秸秆还田可以部分缓解土壤酸化。秸秆还田配施氮肥能够显著提高0~20 cm土层土壤酶活性,N2处理时秸秆还田条件下的土壤脲酶、酸性磷酸酶和蔗糖酶活性分别比对照提高了95.7%、14.3%和19.8%。秸秆还田配施氮肥能够显著提高土壤速效钾含量,秸秆还田比秸秆不还田的土壤速效钾含量在同一施氮水平下的增幅介于15.8%~22.9%之间。碱解氮和有效磷的含量与施氮量呈显著正相关,秸秆还田比秸秆不还田的碱解氮和有效磷含量在N4处理下显著降低。这些结果为在秸秆还田模式下通过配施适量氮肥来达到作物增产的目的提供了土壤学基础。

Based on the 11-year-old located fertilization experiment,we analyzed the changes of physic-chemical properties in different soil layers under the mode of corn straw return plus nitrogen fertilizers with the aim of providing scientific theory and practical basis for the field nutrient management of high-yield crop cultivation.In this study,corn straw return to or non-return to field was the main factor,and five nitrogen levels of 0(CK),90(N1),180(N2),270(N3)and 360(N4)kg·hm^(-2) as the auxiliary factor to design the crack zone.We determinated pH,activity of urease,acid phosphatase and sucrase,and contents of alkali-hydrolyzable nitrogen,available potassium and available phosphorus in 0~20 cm and 20~40 cm soil layers.Our results demonstrated that compared with the CK,straw return plus nitrogen fertilizer had a greater impact on the physical and chemical properties in the 0~20 cm soil tillage layer whereas less impact on those in the 20~40 cm soil layer.The over-application of nitrogen fertilizer would aggravate soil acidification and straw return might partially alleviate the soil acidification.Straw return plus nitrogen fertilizer significantly increased the soil enzyme activity.Compared with the CK,the soil urease,acid phosphatase and sucrase activity in the straw return under N2 treatment increased by 95.7%,14.3%and 19.8%,respectively.Straw return plus nitrogen fertilizer significantly increased the available potassium content.Under the same nitrogen level,the available potassium contents in the straw return increased by 15.8%~22.9%when compared to the non-straw return.The contents of alkali-hydrolyzable nitrogen and available phosphorus were significantly positively correlated with the amount of nitrogen applied.Their contents in straw return were significantly lower than those in non-straw return under N4 treatment.In summary,our results provide a soil science basis for the enhancement of crop yield via applying appropriate amount of nitrogen fertilizer under the mode of straw return.