| Wheat and corn are one of the major crops in China,and they are the crops with the largest cultivation area in North China.The current agricultural ecology has problems of environmental degradation,farmland degradation and soil nutrient loss,etc.The selection of reasonable tillage techniques plays a very important role in enhancing the agricultural condition by playing a more substantial role in the utilization of land resources,water resources and soil biological resources.At present,the main applied technologies are no-till,deep tillage and rototill,while crop straw is an important resource for agricultural production cycle.This experiment takes wheat-corn biannual system,a typical production system in the North China Plain,as the main research object,and analyzes the influence of tillage methods on soil physical and chemical properties and productivity,establishes a soil quality evaluation system suitable for the region,and analyzes the nutrients of corn stover in different harvesting sections,in order to provide a reference for the selection of the optimal system of straw return and tillage methods and the utilization of corn stover in the region.The results of this study are summarized below.Wheat-corn rotation is one of the common crop cultivation patterns,and there has been a lot of research on wheat-corn rotation pattern at home and abroad.At present,a large number of experiments have been conducted to investigate the effects of wheat-corn crop rotation on crop yield and quality,the changes of soil physical and chemical properties and the effects on soil carbon dioxide emissions under the crop rotation pattern,and to clarify the effects of the crop rotation pattern on agricultural production.In this paper,the effects of different tillage methods on the productivity and soil quality of wheat and corn fields in the North China Plain were studied and discussed.The results indicate that the cultivation mode can significantly improve the yield and economic benefits of wheat jade farmland to some extent,and also have a certain improvement effect on soil quality.(1)Deep tillage treatment increases wheat yield by increasing the number of grains per spike.Compared with no tillage,deep tillage treatment increased the number of wheat grains per ear and the effective number of wheat ears,reduced the weight of 1000 grains,increased corn yield,and reduced wheat yield.From the analysis of cultivation methods,deep tillage can evenly flip the soil,forming a soil plow layer where both virtual and solid coexist,alleviating problems such as soil compaction,facilitating the infiltration of groundwater,improving the development of root systems,and enhancing the robustness of plants.The growth advantage can be transformed into a yield advantage.(2)Both rotary tillage and deep tillage can reduce the surface soil bulk density to varying degrees,while deep tillage can increase the deep soil moisture content.The deep tillage treatment had the best effect on reducing soil bulk density during the wheat season,with a significant decrease of 18.1%(p<0.05)compared to the no tillage treatment.In the 2022 corn season,deep tillage significantly increased the water content by 28.2%(p<0.05)in a soil layer of 20-40 cm compared to no tillage treatment.(3)No tillage and deep tillage significantly improved soil fertility.The treatments of no tillage and deep tillage significantly increased the organic carbon,total nitrogen,available phosphorus,and available potassium in the 0-20 cm soil layer,while the distribution of various indicators in the conventional tillage treatment was more uniform in the 0-40 cm soil layer.Returning straw to the field can significantly increase soil organic carbon,total nitrogen,available phosphorus,and available potassium.The increase in depth tillage treatment is significant,while the increase in no tillage treatment is reduced.(4)There are significant differences in soil aggregate content under different cultivation modes.There is a significant difference in the total content of soil aggregates in the rotation mode of returning straw to the field.In the 0-20 cm soil layer,the proportion of soil aggregates with different particle sizes in the soil is not significantly different.However,in the 20-40 cm soil layer,under the rotary and deep tillage modes,the content of soil aggregates with particle sizes greater than 2 mm in the soil is significantly higher than that under the no tillage mode.The soil aggregates with particle sizes ranging from 0.053 to 0.25 mm showed a significantly smaller trend in rotary tillage compared to no tillage and deep tillage.(5)The cultivation method has a significant impact on soil physical properties and soil enzyme activity.The soil bulk density and enzyme activity increased in the treatments of no tillage and deep tillage.Returning straw to the field reduces soil bulk density and increases soil moisture content.Under no tillage treatment,the activities of soil invertase and urease were significantly higher than those of the other two tillage treatments,indicating that no tillage enhanced the activity of soil microorganisms.In terms of crop yield,both rotary tillage and deep tillage are effective tillage systems,while deep tillage is the most effective in improving soil quality.The results also showed that the wheat maize farming system in the North China Plain might not be suitable because of the negative impact of no tillage on soil quality.Overall,after two years of treatment,no tillage straw returning(NT),rotary tillage straw returning(RT),and deep tillage straw returning(DT)did not significantly increase crop yield,but could maintain and improve soil productivity.The effect of rotary tillage on improving soil productivity is not significant;Deep tillage with straw returning has no advantage in improving soil fertility during the wheat season,but its comprehensive effect is outstanding during the corn season;Returning straw without tillage to the field can improve the nutrient content of the subsoil,increase carbon sequestration in the subsoil,and enhance the versatility of the ecosystem,making it a good model for improving the quality of deep soil. |
