| Fresh corn,one of the three major types of corn,has a unique taste and nutritional value,which has increased its demand both at home and abroad,however,the unreasonable application of chemical fertilizer brings a series of problems to crops and soil environment,which restrict the development of fresh corn and other crops.Based on the principle of equal amount of nitrogen,phosphorus and potassium,two experiments of organic alternative fertilizers were carried out on fresh corn.The first experiment was conducted in 2019.The experiment was divided into two seasons,spring corn and autumn corn,six treatments were set,including no fertilizer treatment(CK),full-quantity fertilizer application(CF),reduced30% fertilizer application(RF),30% fertilizer replacement with chicken manure organic fertilizer(RF+OF),30% fertilizer replacement with vermicompost from pig manure(RF+PF)and 30% fertilizer replacement with vermicompost from kitchen waste(RF+KF);Experiment two: vermicompost organic manure and green manure were used to replace chemical fertilizers in the winter of 2019,eight treatments were set,including no fertilizer treatment(CK),full-quantity fertilizer application(CF),reduced 40% fertilizer application(RF),40%fertilizer replacement with chicken manure organic fertilizer(RF+OF),40% fertilizer replacement with vermicompost from pig manure(RF+PF),40% fertilizer replacement with vermicompost from kitchen waste(RF+KF),40% fertilizer replacement with Astragalus sinicus turning over(RF+ZY),40% fertilizer replacement with vetch turning over(RF+SZ).Under different organic fertilizer substitution conditions,the effects of chicken manure organic fertilizer,two kinds of vermicompost organic fertilizer(pig manure and kitchen garbage)and two kinds of green manure(Astragalus sinicus and vetch)on the growth,yield,photosynthetic characteristics,fruit quality(including seed heavy metal content),plant nutrient accumulation,soil fertility,heavy metal and biological properties of fresh corn were studied,then the suitable fertilization measures for fresh corn were selected.The main findings are as follows:In the experiment of organic manure replacing partial chemical fertilizer,RF+OF,RF+PF,RF+KF treatments can improve the yield and quality of fresh corn,RF+PF and RF+KF treatments were better than RF+OF treatment,and the single fruit weight and yield of two vermicompost treatments were closest to CF treatment.Compared with CF treatment,the soluble protein content of corn treated with RF+PF and RF+KF increased by 33.39%,8.23%,15.34%,22.44% respectively in the two seasons.The dry matter accumulation of RF+KF and RF+KF treatments can reach the level of CF treatment.Two vermicompost treatments can increase soil organic matter content.Compared with CF treatment,the increase in soil organic matter content of RF+PF and RF+KF treatments in spring corn was reached 15.61%,24.20%,and reached 13.78%,21.20% in autumn corn,RF+KF treatment increased more than RF+PF treatment.Organic substitution of each treatment increased the content of copper and zinc in spring corn kernels,compared with other treatments,reached the maximum in RF+PF treatment,and the increase range was 21.47%～81.45%,14.69%～107.39%,respectively.But the difference was not obvious in autumn corn.Under the condition of replacing 30% of chemical fertilizers with organic materials,combining spring and autumn corn growth,yeild,quality and soil fertility and other factors,the overall effect of replacing vermicompost from kitchen waste is better than other organic alternative treatments.In the experiment of vermicompost organic fertilizer and green manure replacing partial chemical fertilizer,compared with CK treatment,the yield of each fertilization treatment increased significantly,with an increase range of 16.94%～52.42%.Among them,CF,RF+PF,RF+KF,RF+ZY,and RF+SZ treatments reached 49.19%,52.42%,50.81%,50.00%,39.52%,respectively.The VC content was significantly higher than the two-vermicompost organic fertilizer replacement treatment,with an average increase of 27.39%.At the same time,the RF+KF treatment and RF+ZY treatment significantly increased the soluble sugar content,and the increase range was 23.08%～79%,63.05～116.54%,respectively.The dry matter accumulation of each treatment of organic replacement was higher than that of CF treatment,and reached the maximum in RF+OF treatment,and the total accumulation of nitrogen,phosphorus and potassium of the plant reached the maximum in RF+PF treatment.Organic substitution treatments can alleviate the decrease of soil p H.Compared with CK treatment,CF treatment significantly reduces soil p H.Organic fertilizer substitution and green manure replacement treatments all increase soil p H.Compared with CF treatment,each organic substitution treatment increase soil p H significantly.RF+KF treatment has the largest increase,reaching 13.18%.Compared with CF treatment,RF+PF treatment and RF+KF treatment have an increase in effective phosphorus content ranging from 11.79% to 27.40%.Two green manures replace the soil significantly.The increase range of available potassium content is 36.64%～43.33%.Fertilization can increase bacterial diversity.RF+PF and RF+KF treatments improve bacterial diversity overall better than other treatments.Compared with CF treatment,two vermicompost treatments.The average increase rates of the bacteria Chao1,Observed species,Shannon and Simpson indexes were 26.95%,27.32%,12.14%,and 2.67%,respectively.The dominant phyla of bacteria in all treated soils are Proteobacteria,Actinomycetes and Firmicutes,and the dominant fungal phyla are Ascomycota,Mortierella and Basidiomycota.The CF treatment increased the relative abundance of the Ascomycota,and the two vermicompost treatments significantly increased the relative abundance of the Mortierella.Under the condition of replacing 40% of chemical fertilizers with organic materials and considering factors such as corn growth,yeild,quality and soil fertility,the replacement effect of two vermicomposts is better than that of green manure replacement.The replacement with vermicompost from kitchen waste is better than the replacement with vermicompost from pig manure.On the whole,no matter 30% chemical fertilizer or 40% chemical fertilizer is replaced by organic manure,the replacement with vermicompost from kitchen waste is better than others in improving yield,quality of fresh corn and soil quality.The results of this study can provide a strong data support and practical basis for the replacement of some chemical fertilizers by organic fertilizer in fresh corn. |
