Effect Of Water And Fertilizer On Maize-wheat Rotation Based On The Method Of “3414”

Water and fertilizers are two important factors for the growth and development of crops,and they are also the two most easily controlled factors.Reasonable management of water and fertilizer is also conducive to high crop yields,while blind management of water and fertilizers is not only unfavorable for the growth and development of crops,but also causes negative impacts such as higher agricultural production costs,lower nitrogen use efficiency,and environmental pollution on sustainable agricultural development.In order to study the water-saving and fertilizer-saving programs for crops with high yields,this experiment took irrigation water and nitrogen and phosphate fertilizers as experimental factors,each set 4 levels,a total of 14 treatments arranged randomly.Level 0 of each factor is no fertilization and no irrigation.Level 1,irrigation 30 mm,nitrogen application 90kg·hm^-2?maize?,75 kg·hm^-2?wheat?,phosphorus application 30 kg·hm^-2?maize?,52.5kg·hm^-2?wheat?;2 Level,irrigation water is 60mm,nitrogen application rate is 180kg·hm^-2?maize?,150 kg·hm^-2?wheat?,phosphorus application amount is 60 kg·hm^-2?maize?,105 kg·hm^-2?wheat?;3 levels The irrigation is 90mm,the nitrogen application amount is 270 kg·hm^-2?maize?,225 kg·hm^-2?wheat?,and the phosphorus application amount is 90 kg·hm^-2?maize?and 157.5 kg·hm^-2?wheat?.Based on the monitoring of crop yield and water nutrient absorption,a regression model between crop yield,biomass,water use efficiency,nutrient uptake and utilization,and water and fertilizer use was established to quantitatively analyze the effects of water and fertilizer use.The result is as follows:?1?Through regression analysis,the quadratic,binary,and ternary quadratic regression models were established for maize and wheat yield and irrigation volume,and nitrogen and phosphate fertilizers respectively.Under the three regression models,the yields of maize and wheat showed the trend of increasing first and then decreasing with the increase of the three factors.Applying the fitting equation results in the maximum yield of 10240 kg·hm^-2 when the application of 180 kg·hm^-2 of nitrogen fertilizer,56 kg·hm^-2 of phosphate fertilizer,and the irrigation water is 60 mm,and the input-output ratio is 8.66.The recommended fertilization indicators for obtaining the best economic output of 9993 kg·hm^-2 are:nitrogen fertilizer N169 kg·hm^-2,phosphate fertilizer P₂O₅ 53 kg·hm^-2,irrigation amount 61 mm,and the ratio of production-to-investment is 8.84.In the wheat experiment,the fitting equation results in the maximum yield of 7195 kg·hm^-2 when the application of 150 kg·hm^-2 of nitrogen fertilizer,106 kg·hm^-2 of phosphate fertilizer,and the irrigation water is 60 mm,and the input-output ratio is 5.33.The recommended fertilization index for obtaining the best economic yield of 7,068 kg·hm^-2 is:nitrogen fertilizer N 143 kg·hm^-2,phosphate fertilizer P₂O₅ 94 kg·hm^-2,irrigation amount 61 mm,and the production-to-investment ratio is 5.62.?2?The biomass of maize and wheat increased first and then decreased with the increase of nitrogen?phosphorus application amount and irrigation amount.According to the fitted quadratic equations,the biomass of maize can be up to 19889 kg·hm^-220714kg·hm^-2 when the nitrogen application amount was 179 kg·hm^-2200 kg·hm^-2,the phosphorus application amount was 27 kg·hm^-250 kg·hm^-2,and the irrigation amount was61 mm to 90 mm.The best ratio of nitrogen fertilizer,phosphate fertilizer and irrigation water can be 4.3:1:1.7(the unit of N and P is kg·hm^-2,the unit of water irrigation is mm,the same below).The nitrogen application rate is 157 kg·hm^-2177 kg·hm^-2,Phosphate fertilizer dosage is 107 kg·hm^-2124 kg·hm^-2,irrigation amount is 58mm⁶5mm,wheat biomass can reach 14590 kg·hm^-215158 kg·hm^-2.The optimum ratio of nitrogen fertilizer,phosphate fertilizer and irrigation volume is 2.7:1.9:1.?3?Through the establishment of regression models between the water use efficiency of maize and wheat and the amount of irrigation water and nitrogen and phosphate fertilizer,the water use efficiency increased first and then decreased with the increase of the three factors.According to the comprehensive analysis of three models,when the nitrogen application rate is 77 kg·hm^-2 to 138 kg·hm^-2,the phosphorus application rate is 46 kg·hm^-2to 49 kg·hm^-2,and the irrigation water volume is 49 mm to 67mm,the water use efficiency of maize can reach 2.19 kg·m^-3 to 2.51 kg·m^-3.Nitrogen application rate is 103 kg·hm^-2 to136 kg·hm^-2,phosphorus application rate is 69 kg·hm^-2 to 91 kg·hm^-2,irrigation water is57mm to 79mm,the water use efficiency of wheat can reach 2.06 kg·m^-3 to 2.25 kg·m^-3.?4?The effects of water and fertilizer application on nutrient uptake of maize showed that the amount of nitrogen uptake increased first and then decreased with the increase of nitrogen application amount and irrigation amount,and increased with the increase of phosphorus application amount;the absorption of phosphorus by maize did not change with the amount of nitrogen application and increased with the increase of phosphorus application amount,with the increase of irrigation volume it has increased first and then decreased.Maize potassium absorption increases first and then decreases with the increase in the amount of phosphorus and irrigation water,and does not change significantly with the amount of nitrogen application.Different from maize,the nutrient absorption of wheat showed that the amount of nitrogen uptake increased with the increase of nitrogen application rate,increased first and then decreased with the increase of phosphorus application amount and irrigation amount.The absorption of phosphorus in wheat increased first and then decreased with the increase of nitrogen application rate,and it increased with the increase of phosphorus application amount,but did not change significantly with the increase of irrigation amount.The uptake of potassium by wheat increased with the increase of nitrogen application rate and phosphorus application amount,and there was no obvious change rule with irrigation amount.?5?The effect of water-fertilizer consumption on crop nutrient use efficiency was as follows:Nitrogen use efficiency of maize and wheat increased first and then decreased with the amount of phosphorus and irrigation.The phosphorus application rate with the highest nitrogen use efficiency was 30 kg·hm^-2?maize?or 94 kg·hm^-2?wheat?and the irrigation amount was 60 mm?maize,wheat?.The phosphorus use efficiency of maize and wheat increased first and then decreased with the increase of nitrogen application rate and irrigation amount.Maize phosphorus utilization efficiency was the highest when the nitrogen application rate was 180 kg·hm^-2 and the irrigation amount was 69mm,which was 175 kg·kg^-1 and 180kg·kg^-1.The phosphorus utilization efficiency of wheat was the highest when nitrogen application rate was 176 kg·hm^-2 and irrigation water amount was 60 mm,which were 67kg·kg^-1 and 66 kg·kg^-1.The K utilization efficiency of maize and wheat increased first and then decreased with the amount of phosphorus applied.When the P application amount was43 kg·hm^-2,the K utilization efficiency of maize reached the maximum value of 230kg·kg^-1.The K utilization efficiency of wheat reaches a maximum of 130 kg·kg^-1 when the phosphorus application rate is 52.5 kg·hm^-2.