Effects Of Organic Substitution On Low-fertility Soil And Crop Growth In The Ancient Bed Of Yellow River In Jiangsu Province

The ancient bed of Yellow River in northern Jiangsu is rich in cultivated land resources,and it is an important grain producing area in Jiangsu Province.However,due to the low soil basic fertility and poor soil structure in this area,the soil comprehensive productivity has much room for improvement.Application of organic fertilizer is an important method of soil fertility.It can improve soil properties and enhance soil fertility.At the same time,it can replace some chemical fertilizers to meet the needs of crop growth.Partial replacement of chemical fertilizers with organic fertilizers not only reduces the use of chemical fertilizers,but also great significance to improves the soil fertility.This study conducted a field experiment on the current status of agricultural production in ancient bed of Yellow River,explored the impact of organic fertilizer substitution on irrigated soil fertility and crop yield in the ancient bed of Yellow River,and explained the effect of organic fertilizer substitution on the fertility of fluvo-aquic soil,and promoted rationality in the region.The organic fertilizer alternative provides a theoretical basis.The experimental field is located in Sanba Village,Jiepai Town,Binhai County,Jiangsu Province.Six different treatments were set up,namely no fertilization(CK);single application of chemical fertilizer(F);chemical fertilizer combined with organic fertilizer(FM0.4);In the case of equal total nutrient of NPK,20%(F0.8M0.2),40%(F0.6M0.4)and 60%(F0.4M0.6)of fertilizer were replaced by organic fertilizer respectively.Field trials were carried out in wheat-maize rotation system and wheat-rice rotation system respectively;soil and plant samples were collected during harvesting of each season crop,and crop yield was measured.Effects of different rotation systems on crop yield,soil fertility,crop nutrient uptake and fertilizer utilization to explore the replacement of organic fertilizer in the ancient bed of Yellow River.The research results are as follows:1.From the perspective of crop yield,fertilization can significantly increase the crop yield of different rotation systems(p<0.05).Compared with single application of chemical fertilizer,the application of organic fertilizer to chemical fertilizer did not significantly increase crop yield;the wheat-maize rotation system organic fertilizer replaced fertilizer in the wheat season.The yield was significantly reduced.When organic fertilizer replaced 60%chemical fertilizer,its yield was significantly reduced(p<0.05),but there was no significant difference in maize yield.Under the wheat-rice rotation system,there is no significant difference in wheat yield between organic fertilizer instead of chemical fertilizer and single application of chemical fertilizer.While the yield of rice with different proportions of organic fertilizers was significantly lower than that of single fertilizers.2.The replacement of organic fertilizer significantly increased the organic matter content of the soil(p<0.05),the soil organic matter increased by 8.07%-36.61%in the wheat-maize rotation system,and the organic matter of the wheat-rice rotation system increased by 7.69%-40.22%.As the proportion of fertilizer substitution increases,the soil organic matter content increases.With the increase of organic fertilizer replacement ratio,the content of total nitrogen and available potassium in soil was decreased,while the content of soil phosphorus and alkali nitrogen were gradually increased in wheat-maize rotation system.The content of total phosphorus,alkali nitrogen and available potassium in soil increased gradually while the total nitrogen decreased in wheat-rice rotation system.Different fertilization treatments did not significantly affect the stability and distribution of soil aggregates in the two rotation systems.3.The replacement of chemical fertilizer by organic fertilizer in wheat jade rotation system significantly enhanced soil basic respiration(p<0.05).The more substitution of organic fertilizer,the stronger the soil respiration;the wheat jade rotation system,with the increase of organic fertilizer dosage,wheat season Soil oxidase activity increased gradually,while soil phenoloxidase increased gradually in maize season,and there was no significant change in peroxidase.In the wheat-rice rotation system,the respiration of the wheat season increased with the increase of the application rate of organic fertilizer;the difference of respiration in rice season was not significant;the activity of soil oxidase did not change significantly.In the wheat jade rotation system,the activity of carbon,nitrogen and phosphorus circulating enzymes in the soil gradually decreased with the increase of the proportion of organic fertilizer replacement.In the wheat-rice rotation system,the replacement of organic fertilizer significantly increased the carbon,nitrogen and phosphorus cycles of soil.The total activity of the enzyme.4.From the perspective of crop nutrient absorption,fertilization measures increased the nutrient content and accumulation of various parts of the crop;the difference of fertilizer contribution rate and agronomic efficiency between different fertilization measures was not obvious;with the increase of organic fertilizer replacement ratio,the partial productivity of nitrogen fertilizer gradually increased.Increase,while the partial productivity of phosphate fertilizer and potassium fertilizer gradually decreases.In summary,due to the low basic soil fertility in the ancient bed of Yellow River,the replacement of chemical fertilizer by organic fertilizer did not show an increase in crop yield,but the input of organic fertilizer effectively improved the nutrient status of the soil;Therefore,it is necessary to maintain the amount of chemical fertilizer and increase the application of organic fertilizer to improve poor soil traits in this area.