玉米-大豆带状套作对土壤肥力的影响

Effect of Maize-Soybean Relay Strip Intercropping on Soil Fertility

【目的】明确玉米大豆带状套作对土壤肥力、酶活性、团聚体含量的影响以及作物产量的变化。【方法】以“登海605”为供试玉米品种,以“南豆12”为供试大豆品种,设置玉米-大豆带状套作、玉米单作和大豆单作3个处理,系统研究不同处理对土壤有机质、全氮、全磷和有效磷、全钾和速效钾含量,pH、容重,脲酶、蔗糖酶、酸性磷酸酶、硝酸还原酶活性、团聚体含量和作物产量的影响。【结果】玉米-大豆带状套作显著提高了玉米和大豆带土壤的有机质、有效磷、速效钾等养分含量,其中玉米带增幅分别为18.1%、14.9%和21.8%,大豆带有机质和速效钾增幅分别为17.7%和34.9%,而有效磷增幅较小且不显著,并保持了全氮、全磷、全钾含量和pH的稳定。玉米带土壤容重显著下降3.3%,大豆带则显著增加4.7%。带状套作显著提高了土壤蔗糖酶和脲酶的活性,玉米带增幅为16.3%和20.5%,大豆带增幅为133.7%和66.2%,酸性磷酸酶和硝酸还原酶活性保持稳定。带状套作促进了大粒径团聚体的形成,套作玉米和大豆带>2 mm团聚体分别显著提高18.8%和22.2%,其他各粒级的小团聚体不同程度下降。带状套作玉米较单作千粒重、穗粒数、有效株数和产量均无显著差异。带状套作大豆有效株数、单株粒数分别较单作显著下降12.9%、26.5%,百粒重无显著差异,最终使大豆产量达到单作的60.9%。【结论】玉米-大豆套作模式提高了土壤肥力,显著增加了有机质、速效钾、有效磷等的含量,维持了土壤中全氮、全磷、全钾含量和pH的稳定,并显著提高了土壤脲酶和蔗糖酶的活性,从而有利于土壤养分转化和植物吸收利用。带状套作还促进微小团聚体向稳定的大团聚体转化,从而提高了土壤的通透性和保水保肥能力,一定程度上影响土壤的化学性质,满足了玉米和大豆生长需要。因此,玉米-大豆带状套作可以改善土壤的化学性质和物理性质,提高土壤肥力,保持与单作相当的玉米产量,并能额外收获相当于单作产量60.9%的大豆。

【Objective】This paper was conducted to clarify the effects of maize-soybean relay strip inter⁃cropping on soil fertility,enzyme activity,aggregate content,and changes in crop yield.【Method】This study used"Denghai 605"as the test maize variety and"Nandou 12"as the test soybean variety.It sets up treatments of maize-soybean strip intercropping,monoculture of maize and monoculture of soybean to systematically investigate the effects of different treatments on soil organic matter,total nitrogen,total phosphorus and available phosphorus,total potassium and available potassium,pH,bulk density,ure⁃ase,sucrase,acid phosphatase,nitrate reductase,aggregates content,and crop yield.【Result】Maizesoybean relay strip intercropping significantly increased the organic matter,available phosphorus,and available potassium in the soil of the corn and soybean strips,with increases of 18.1%,14.9%,and 21.8%,respectively,in the maize strip and increases of 17.7%and 34.9%in organic matter and avail⁃able potassium,respectively,in the soybean strip.The increase in available phosphorus was small and not significant,and the total nitrogen,total phosphorus,and total potassium content and pH were main⁃tained.The bulk density of the soil in the corn strip significantly decreased by 3.3%,while that in the soy⁃bean strip significantly increased by 4.7%.Strip intercropping significantly increased the activity of su⁃crose enzyme and urease by 16.3%and 20.5%,respectively,in the maize strip and 133.7%and 66.2%,respectively,in the soybean strip.The activity of acid phosphatase and nitrate reductase was stable.Strip intercropping promoted the formation of large aggregates,with significant increases in the>2 mm aggre⁃gate of 18.8%and 22.2%in the intercropping maize and soybean strips,respectively,and decreases in the other aggregate sizes to varying degrees.There was no significant difference in thousand-grain weight,grain number,effective plant number,and yield between strip intercropping maize and monoculture corn.The effective plant number and grain number per plant in strip intercropping soybean were significantly lower than those in monoculture,by 12.94%and 26.51%,respectively,while the hundred-grain weight was stable,ultimately resulting in a soybean yield of 60.9%of that monoculture.【Conclusion】The re⁃lay maize-soybean intercropping pattern improves soil fertility,significantly increasing the contents of or⁃ganic matter,available potassium,and available phosphorus.It maintains the stability of total nitrogen,total phosphorus,total potassium content,and pH in the soil.Additionally,it significantly increases the activities of soil urease and invertase,thereby facilitating soil nutrient transformation and plant absorp⁃tion and utilization.Strip intercropping also promotes the transformation of small aggregates into stable large aggregates,thereby improving soil permeability and the ability to retain water and fertilizers.To a certain extent,it affects the chemical properties of the soil and meets the growth needs of maize and soy⁃beans.Therefore,maize-soybean strip intercropping can improve both the chemical and physical proper⁃ties of the soil,enhance soil fertility,maintain comparable maize yields to monoculture,and can addi⁃tionally harvest soybeans equivalent to 60.9%of the yield of monoculture soybeans.