| Coastal saline alkali land is an important land resource an reserve cultivated land in China.Under the severe sitution of serious soil degradation and land resource shortage,it has important practical and long-term significance to carry out green development and sustainable utilization of coastal saline alkali land resources.Scientific development and rational use of these reserve land resources is an important part of the construction of the "Yellow River Delta high efficiency eco economic zone".Based on the coupling of water and fertilizer,this paper studies the interaction and regu lation mechanism between water,fertilizer,and crops in coastal saline alkali land,(F1:flood irrigation,360mm,Dl:drip irrigation,360mm,D2:drip irrigation,288mm,D3:drip irrigation,216mm),four nirrogen fertilizer treatments(N1:280kg hm 2,N2:196kg hm2,N3:112kg hm-2,N4:0kg hm-2)were set it this experiment.The main conclusions are as follows:(1)The average water content of soil profile before and after irrigation was significantly affected by irrigation mode,At the root density of 0-30cm,the water content of drip irrigation is slightly higher than that of flood irrigation,and the difference between flood irrigation and drip irrigation incre ases with the decrease f ritrogen application,Both flood irrigation and drip irrigation have the advantages of Washing salt.The average salt content of the section treated by flood irrigation is less than that treated by drip irrigation;the average salt content of the section treated by flood irriga tion is less than that of drip irrigation;the average salt content of the section treated by flood irrigation is less than that of drip irrigation at 0-5 points,and that of the section treated by flood irrigation is greater than that of drip irrigation at 10-40cm points.The change of ammonia nitrogen content in diffuse irrigation was greater than that in drip irrigation.With the decrease of nitrogen application,the difference of ammonia nitrogen content between flood irrigation and drip irrigation increased.The difference of nitrate nitrogen content in soil is mainly shown in the range of 0-20cm.Under the condition of the same irrigation water and nitrogen amount,except for the amount,except for the low nitrogen treatment,the nitrate nitrogen content of drip irrigation is higher than that of flood irrigation.(2)for the same irrigation amount,the average water content of N1 is the lowest,the average water content of N4 is the highest,and N2 and N3 are basically similar.When the amount of fertilizer applied was the same,the salt content increased with the decrease of irrigation water,and both D1 and D2 had salt accumulation points in the early stage of growth,while D3 had no obvious inflection point.When the irrigation amount is the same,the salinity content increases with the decrease of the application amount of nitrogen fertilizer.The salinity difference between treatments caused by the nitrogen fertilizer gradient decreases,and there is an obvious inflection point of nitrate nitrogen in the soil layer.When the irrigation amount is D1,the inflection point is basically 40cm,and when the irrigation amount is D2 and D3,the inflection point is basically 30cm.(3)by comparing the change process of plant height,leaf area index and biomass with time in each Logistic model of water and fertilizer treatment,the root mean square error and fitting degree of the fitting parameters were better,and the Logistic model could better fit the change process of each growth index with time.The empirical models of maize plant height,leaf area index and biomass growth with time in coastal saline-alkali land were presented.(4)when only considering crop yield,D1N2(360mm,280kg hm-2)had the highest yield,D1N2(360mm,196kg hm-2)and D2N2(288mm,196kg hm-2)were recommended,and D2N2 was recommended after considering crop yield,water and fertilizer utilization efficiency and soil residual nitrogen. |
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