| In this experiment,the wheat-jade rotation system in Huang-Huai-hai plain,southern Henan sand and ginger black soil was taken as the research object,and field plot test was adopted.Normal fertilization(T0)and no nitrogen treatment group(N0)were divided into control group,organic fertilizer replacement of nitrogen reduction20%(T20),40%(T40),60%(T60),80%(T80),100%(T100),and 7 treatments.Replacement fertilization was applied in wheat season,and the same amount of fertilizer was applied in corn season.The dry matter accumulation,photosynthetic index,crop nutrient accumulation,lodging resistance,soil basic physical and chemical properties,soil enzyme activity and so on during the growth process of wheat and corn were studied and analyzed,which provided the basis for the promotion of organic fertilizer replacement technology on sand ginger black soil farmland.The main results are as follows:(1)All treatments of organic fertilizer reduction could increase crop yield,and the effect of organic fertilizer reduction ratio of 60% was better.The number of grains per ear of wheat increased by 1%-7.3% and wheat yield increased by 1.5%-11.2%.The 100 grain weight of corn increased by 10.1%-16.3 and the yield of corn increased by 4.7%-9.6%.The number of grains per ear increased by 7.3% and wheat yield increased by 11.2% in treatment with 60% reduction ratio compared with normal fertilization.The number of grains per ear,100 grain weight and yield of corn in T60 increased by 6.3%,16.2% and 9.6%,respectively,and were the highest.(2)The dry matter accumulation of crops at different growth stages showed a trend of first increasing and then decreasing with the increasing proportion of organic fertilizer replacement,and the dry matter accumulation of organic fertilizer replacement treatment was higher than that of T0.Corn is also showing the same trend as wheat.No matter in wheat or corn,dry matter accumulation of T60 was the highest in the same growth period.In wheat jointing,flowering and ripening periods,dry matter accumulation of T60 increased significantly by 25.8%,13.8% and 15.3%compared with that of T0.In maize jointing,spinning and ripening periods,dry matter accumulation of T60 was significantly increased by 25.8%,13.8% and 15.3%.The dry matter accumulation of this treatment was significantly increased by 26.4%,23.5% and 7.5% compared with T0 treatment.(3)In the same growth period,the SPAD value of functional leaves,net photosynthetic rate,stomatal conductance and transpiration of organic fertilizer replacement treatment were all higher than T0.The SPAD value,net photosynthetic rate,stomatal conductance and transpiration rate of functional leaves of T60 were the highest.In the jointing and flowering stages of wheat,the SPAD value of functional leaves of T60 was significantly increased by 43.6% and 32.5% compared with T0,and the net photosynthetic rate was significantly increased by 13.2% and 30.1%compared with T0.Compared with T0,pore conductance increased by 22.2% and18.75%,transpiration increased by 9.4% and 15.8%.In the jointing and flowering stages of maize,the SPAD value of maize functional leaves in T60 was significantly increased by 31.8% and 8.2%,the net photosynthetic rate was significantly increased by 37.1% and 30.5%,stomatal conductance was significantly increased by 26.3% and50%,and transpiration was significantly increased by 37.3% and 32.3% compared with T0.(4)In the wheat-jade rotation system,the accumulation of nitrogen,phosphorus and potassium nutrients in the organic fertilizer replacement treatment was higher than that in T0 during the same growth period.With the increase of the reduction ratio,the crop nutrient accumulation showed a trend of first rising and then declining,and the nutrient accumulation of T60 was the highest in the same growth period.In the jointing stage,the accumulation of nitrogen,phosphorus and potassium in T60 increased significantly by 37.6%,28.8% and 40.5% compared with that in T0.In the flowering stage of wheat,the accumulation of nitrogen,phosphorus and potassium in T60 increased by 37.6%,37.8% and 29.6% compared with that in T0.The accumulation of nitrogen,phosphorus and potassium in T60 increased by 12.4%,40.9% and 27.3% compared with that in T0 in wheat maturation stage.At the jointing stage,the accumulation of nitrogen,phosphorus and potassium in T60 increased significantly by 61.1%,133.5% and 12.7% compared with that in T0.The accumulation of nitrogen,phosphorus and potassium in T60 increased by 24.5%,32.8% and 24.5% compared with that in T0 at the spinning stage of maize.The accumulation of nitrogen,phosphorus and potassium in T60 increased by 27.1%,38.0% and 25.3% compared with that in T0.(5)Organic fertilizer replacement treatment can increase soil moisture content,increase soil p H value,reduce soil bulk density,and increase soil organic matter content.The moisture content of T80 and T100 was the highest,increasing by 4.9%and 9.4% compared with that of T0.The bulk density of T40,T60,T80 and T100 T is lower than that of T0.With the increase of the reduction ratio,the p H value of soil in the treatment of organic fertilizer replacement showed an increasing trend,and the content of soil organic matter in the treatment of organic fertilizer replacement presented a trend of increasing first and then decreasing.The content of soil organic matter in the treatment of organic fertilizer replacement was significantly higher than that in T0,and the content of organic matter in T60 was the highest,which was 22.7%higher than that in T0.(6)In the wheat-jade rotation system on sandy ginger black soil,ammonium nitrogen content,nitrate nitrogen content and nitrification potential of each treatment decreased gradually with the passage of wheat growth period.In the jointing stage of wheat,the content of ammonium nitrogen in soil treated with organic fertilizer replacement increased with the increase of replacement ratio.The content of ammonium nitrogen in soil under T20,T40,T60,T80 and T100 was significantly increased by 16.2%,27.2%,36.9%,62.2% and 61.7% compared with that under normal fertilization.At the flowering stage of wheat,the ammonium nitrogen content of soil treated with organic fertilizer replacement increased first and then decreased with the increase of the replacement ratio,and the ammonium nitrogen content of soil treated with T60 was the highest.In the three growth stages of wheat jointing,flowering and ripening,soil nitrate nitrogen showed a trend of first increasing and then decreasing with the increase of replacement ratio,and the highest nitrate nitrogen content was found in T60,which significantly increased by 36.5%,18.9% and 86.2%compared with T0.In the jointing stage of wheat,the nitrification potential of soil treated with organic fertilizer replacement was higher than that of T0.(7)Organic fertilizer replacement treatment affected soil enzyme activities,and different enzymes affected different trends.With the passage of wheat growth period,the content of soil sucrase in each treatment showed a trend of decreasing gradually.In the same growth period,with the increase of replacement proportion,the soil sucrase content of organic fertilizer replacement treatment had a trend of increasing first and then decreasing,and the soil sucrase content of organic fertilizer replacement treatment was higher than that of T0.In the three growth periods,the soil sucrase content of T60 was the highest,which significantly increased by 11.8%,29.8% and24.6% compared with that of T0.With the passage of wheat growth period,soil urease content in all treatments showed a trend of decreasing gradually.In the same growth period,with the increase of substitution proportion,soil urease content of organic fertilizer replacement treatment had a trend of gradual decrease,and soil urease content of organic fertilizer replacement treatment was lower than that of T0.With the passage of wheat growth period,soil neutral phosphatase content of each treatment did not change significantly from the joining stage to the flowering stage,but showed a decreasing trend from the flowering stage to the maturity stage.In the same growth period,with the increase of replacement proportion,the neutral phosphatase content in soil of organic fertilizer replacement reduction treatment had a trend of first increasing and then decreasing,and the neutral phosphatase content in soil of organic fertilizer replacement reduction treatment was higher than that of T0.In the three periods,the neutral phosphatase content in soil of T60 was the highest,significantly increasing by 35.1%,38.9% and 50.2% compared with that of T0.In wheat and jade rotation system,organic fertilizer instead of chemical fertilizer can improve the sand ginger black soil by reducing soil bulk density,increasing soil p H value,increasing soil moisture content and increasing organic matter content,and promote the rapid and stable operation of soil ecosystem by adjusting soil nitrogen supply characteristics and improving soil enzyme activity.According to the comprehensive analysis of crop growth and yield and the impact on soil,60%reduction of organic fertilizer was the best reduction ratio of organic fertilizer in this region. |
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