The Coupling Effects Of Water And Fertilizer And Its Rational Utilization Mechanism On Potato In The Northern Foot Of Yinshan Mountain

To reveal the optimal amounts of irrigation and nitrogen fertiliser for potato production in the Northern Foot of Yin Mountain,the coupling effects of nitrogen fertiliser and irrigation on the growth,yield,water use efficiency and nitrogen use efficiency of potato were analyzed based on the field experiments,moreover the application of APSIM was evaluated in this region,the results showed that:1.Coupling of nitrogen and irrigation had significance effects on the growth,yield and yield components of potato.The LAI of potato increased in the early growth stage and declined later,the value of LAI ranged from 0.1 to 2.7 m2·m-2 under different treatments,and the LAI increased with the increase of the amount of irrigation.The change of biomass accumulation of potato showed the curve of"S" in all treatments and the value increased with the increaseof the amount of irrigation.The maximum accumulation of biomass occurred under the treatment of W3N2 with the value of 236.50 g per plant.The biomass accumulation of tuber was the highest,followed by leaf,stem and root.The impacts of irrigation on the allocation of dry matter to different organs was not significance.Potato yields increased with the increase of irrigation,applied nitrogen with the amount of 90 kg·ha-1 produced highest potato yield under the rainfed condition,with the yield of 17.31t·ha-1.The optimal amounts of nitrogen were all 180 kg·ha-1 with the amounts of irrigation of 90 mm,180 mm and 360 mm.Applied irrigation could aggravate the impacts of application of N on the potato yield.Application of nitrogen and irrigation had significantimpacts on the commercial potato rate and tuber weight,the maximum commercial potato rate and tuber weight werefoundunder the treatment of W2N2,the values were 62.85%and 0.48 kg.2.The change trend of potato plant nitrogen uptake presented "S" curve.The total amount of N uptake was highest in the tuber,followed by leaf,stem and root.The plant absorption of N,P and K of potato increased with the increase amount of irrigation.The maximum amount of N,P and K absorption occurred in the N1 treatment under the rainfed condition,the amounts of the absorptions were 69.18?7.72 and 71.56 kg·ha-1 for the tuber,97.04?10.73 and 79.17 kg·ha-1 for the plant.The maximum N,P and K absorption occurred in the W3N2 treatment under the irrigation condition,with the values of 137.80?16.10and 113.84kg·ha-1 for the tuber,183.29?21.10 and 130.41 kg·ha-1 for the plant.N use efficiency increased with the increase amount of irrigation for the potato.The N use efficiency was highest in the N1 treatment under the rainfed condition with the value of 38.02%.The N use efficiency was highest in the treatment of W3N2 under the irrigation condition,with the value of 42.78%.The agricultural efficiency of N increased with the increase of the amount of irrigation,applied 90 kg·ha-1 under the rainfed condition produced the highest N agriculture efficiency with the value of 49.03 kg·ha-1.The N agriculture efficiency was highest in the treatment of W3N2 under the irrigation condition,with the value of 73.85 kg·ha-1.The absorption amount of N was 4.39?5.83 kg per ton of fresh potato.3.Coupling of N and irrigation had significant effects on soil water content.Soil water content increased with the increase of irrigation,however decreased with the increase of application of N.The deficit amount of soil water content in 1 m depth ranged from 1?30 mm in the fallowing period and the recovery amount was ranged from-1.1%to-14.6%.Application of irrigation and N fertilizer had positive effects on the soil water recovery.Water consumption of potato during different growing periods increased with the increase amount of irrigation.Water consumption increased first with the increase amount of N and then decreased.Irrigation had no significant effects on the water use efficiency(WUE)of potato.With increase amount of nitrogen,potato WUE increased first and then decreased.Applied 90 kg·ha-1 N produced highest potato WUE under the rainfed condition,with the value of 73.43 kg ha·mm-1.The WUE of potato was highest in the treatment of W2N2 under the irrigation condition,with the value of 94.22 kg·ha-1·mm-1.4.Coupling of irrigation and application of N had significant effects on the soil nitrate N content.The nitrate nitrogen content in the soil decreased with the increase of irrigation and increased with the increase of application amount of N fertilizer.The relationship between the application of N fertilizer and mineral N residual in the soil was index.The mineral N residual in the soil increased significantly when the application amount of N fertilizer surplused 90 kg·ha-1 underrainfed condition and 180 kg·ha-1 for the irrigation condition.5.Binary quadratic relationship was found among the amounts of irrigation,N fertilizer,yield and plant N absorption.The optimal amount of water and N supply for potato production in this region ranged from 300 to 420 mm and from 191 to 281 kg·ha-1,the potato yield wouldrange from 21.7 to 28.7 t·ha-1.The high yield level of potato ranged from 30.1 to 38.1 t·ha-1 in this region,the water and N fertilizer supply amounts would range from 420 to 690 mm and from 225 to 279 kg·ha-1.6..The modeled results based on the APSIM-potato showed:the optimal amount of N for potato production was 30 kg·ha-1 under the rainfed condition;the optimal amount irrigation for potato production was 120 mm,90 mm and 60 mm for dry years,normal years and wet years under the base soil fertilizer;applied three times of irrigation and N with the amounts of 180 mm and 90 kg · ha-1 produced the maximum potato yield,the optimal stages for irrigation and application of N were emergence,budding and flowering.The application of APSIM need improvement in this region for simulation of irrigation and application of N fertilizer.