Study On Absorption And Utilization Of Maize Nutrients By Substituting Chemical Fertilizer With Organic Fertilizer Under Different Water Supply Rate

The influence of climate change and the uneven distribution of interannual precipitation lead to the reduction of crop yield and the decrease of water use efficiency.The utilization of agricultural and animal husbandry wastes is becoming more and more important in agricultural production,the substitution of chemical fertilizer for agricultural and animal husbandry waste can not only eliminate the environmental pollution but also achieve the efficient use of waste.In this experiment,water supplement by drip irrigation combined with natural rainfall were adopted to study the effects of different water supply,chemical fertilizers,organic fertilizers,and their interactions on the economic and biological yields of maize,and the effects on nitrogen,phosphorus and potassium absorption and nutrient use efficiency in maize.The characteristics of dynamic changes of soil water,ammonium nitrogen,and nitrate nitrogen were also studied,thus to understand the effect of water and fertilizer absorption and utilization under different organic substitution of chemical fertilizers and water supply,So as to achieve the goal of reducing fertilizer and increasing efficiency,stable production of Maize.The main results and conclusions are as follows:1.Effect of organic substitution of chemical fertilizer on maize yield under different water supply.Under this experimental condition,except CK,the trend of maize yield increased first and then decreased with the increase of water supply in each substitution treatment.The yield of different organic substitution treatment was higher than that of regular fertilization（T0）.When the water supply was under the condition of W2（natural precipitation+100 mm during growing period）,which water supply was 667.3 mm during the maize growing period,the yield of organic fertilizer substitution of 25%fertilizer showed in the order of chicken manure substitution of 25%chemical fertilizer（T3）>pig manure substitution of 25%chemical fertilizers（T1）>the cow dung substitution of 25%chemical fertilizers（T2）>straw total returning（T4）.The result showed that organic substitution of chemical fertilizer treatment can significantly increase the maize yield under appropriate water supply,and the yield of chicken manure substitution of 25%chemical fertilizer（T3）was 13616.9 kg/hm²,increased by 2281.6kg/hm²,20.1%higher than that of habitual fertilization（T0）.2.Effect of organic substitution of chemical fertilizer on dry matter accumulation of Maize under different water supply.The change of Maize dry matter accumulation of organic substitute conformed to the"S"type curve under different water supply.The derivation of the logistic equation Y=K/(1+ae^bt)can obtain the maximum rate of maize dry mattert accumulation and the appearing time of maximum accumulation rate.Under different water supply rates,the dry matter accumulation of maize by organic matter replacement of organic fertilizer was 347.6-413.2g/plant,and the maximum accumulation rate was 4.21-4.90g/d/plant,the time of maximum accumulation rate was in maize filling stage,about 87.8-97.6 days after seedling emergency.The maximum accumulation rate of dry matter of maize under various fertilization treatments first increased and then decreased with the increase of water supply.The maximum accumulation rate was reached under the water supply amount of W2 and the maximum accumulation rate of different organic substitution treatment was higher than T0.When the water supply was W2,the dry matter accumulation in different organs of each organic substitution treatment reached the maximum,and the dry matter accumulation of stalk,leaf,husk plus cob and grain treated with chicken manure instead of 25%chemical fertilizer（T3）was 99.60g,82.00g,55.80g,and175.80g respectively.Than the conventional fertilizer（T0）treatment increased by 13.1%,26.0%,5.7%,6.4%.3.Effect of organic substitution of fertilizers on nutrient uptake and utilization of maize under different water supply.The change of Maize nutrient accumulation of organic substitute conformed to the"S"type curve under different water supply.The derivation of the logistic equation Y=K/(1+ae^bt)can obtain the maximum rate of maize nutrient accumulation and the appearing time of maximum accumulation rate.The occurrence time of nitrogen accumulation maximum rate in maize plants was 60.8-84.4 days（Trumpet period,tasselling period,filling period）after seedling emergence.The overall trend of nitrogen use efficiency（utilization,agronomic efficiency,and partial productivity）was in the order of chicken manure replacing 25%chemical fertilizer（T3）>pig manure replacing 25%chemical fertilizer（T1）>cow manure replacing 25%chemical fertilizer（T2）>straw total returning（T4）>habitual fertilization（T0）.Among them,the nitrogen fertilizer utilization rate,agronomic efficiency,and partial productivity of T3 treatment increased by54.3%、67.5%and 13.6%,compared with T0 treatment.The occurrence time of phosphorus accumulation maximum rate in maize was about 74.2-100.9 days（Torting period and filling period）after emergence,and the phosphorus accumulation maximum rate was 0.0109-0.0200g/d/plant.The overall trend of phosphate fertilizer use efficiency was in the order of chicken manure replacing 25%chemical fertilizer（T3）>pig manure replacing 25%chemical fertilizer（T1）>cow manure replacing 25%chemical fertilizer（T2）,straw total returning（T4）>habitual fertilization（T0）.Among them,the ratio of phosphate fertilizer utilization,agronomic efficiency,and partial productivity of T3 treatment increased by 41.9%、185.2%and 13.6%,compared with T0 treatment.The maximum rate of potassium accumulation in maize plants occurred between52.3-61.3 days（Trumpet period and draw period）after emergence,and the maximum rate of potassium accumulation was 0.0480-0.0913 g/d/plant.The overall efficiency of potash fertilizer utilization is as follows:chicken manure replaces 25%chemical fertilizer（T3）>pig manure replaces 25%chemical fertilizer（T1）>cow manure replaces 25%chemical fertilizer（T2）>straw fully returns to field（T4）>habitual fertilization（T0）.Among them,T3 treatment increased the utilization rate of potash fertilizer,agronomic efficiency,and partial productivity by 14.6%,235.8%and 13.6%,compared with T0 treatment.4.Effect of organic substitute of chemical fertilizer on water use efficiency of maize under different water supply.The water use efficiency of maize was decreasing with the increase of water supply.When the water supply of W2（natural precipitation+100mm）was 667.3mm,the water use efficiency under maximum yield of organic substitution of T1,T2,T3 and T4 was 19.32%,18.99%,20.43%and 18.64%,respectively,which was significantly different（P<0.05）to the 17.97%of T0treatment.The water utilization efficiency of organic substitution of 25%chemical fertilizers is higher than that of conventional fertilization（single application of chemical fertilizer）.Increasing the appropriate amount of water supply will ensure the water use efficiency,but significantly increase the crop yield.5.Effect of organic substitution of chemical fertilizer on Soil inorganic nitrogen leaching in soil at mature period of Maize under different water supply.With the increase of water supply,the soil NO₃^--N leaching enhanced gradually.Under the same water supply conditions,the effect on soil NO₃^--N leaching of different organic fertilizer instead of 25%chemical fertilizer treatment showed as habitual fertilization（T0）>chicken manure instead of 25%chemical fertilizer（T3）>pig replace 25%of chemical fertilizers（T1）>the cow dung instead of 25%chemical fertilizers（T2）>straw total returning（T4）.The effect on soil ammonium nitrogen of organic fertilizer replace 25%chemical fertilizer treatment was mainly reflected in the 0-40 mm soil layer under different water supply condition,there was no significant effect in the 60-100mm soil layer,and the concentration of ammonium nitrogen was in lower levels,which was about 1.30-3.50 mg/kg.