Effects Of Acidic Water Soluble Fertilizer On Nutrient Availability In Irrigated Desert Soil

In this experiment,irrigated desert soil was used as test material.According to the result of simulation experiment,we set two applied amount of N fertilizer(N1=450Kg·hm^-2,N2=900Kg·hm^-2),the two irrigation quantity(W1=1500m³·hm^-2,W2=3000m³·hm^-2)and five irrigation fluid's pH?A1=1.5,A2=3.5,A3=5.5,A4=7.5,A5=9.5,and 7.5 is the average pH of local irrigation fluid?,a total of 20 treatments to study the effects of different treatments on soil pH,ammonia volatilization,alkali-hydrolyzed nitrogen,available phosphorus,iron,manganese,copper and zinc contents.The main conclusions of this experiment are as follows:?1?Acidic water soluble fertilizer can significantly reduce the soil pH.In 0⁵cm soil layer,the soil pH of A1 is 7.16⁷.4,which is significantly different from other treatments.Soil pH under each treatment increased with the increase of soil depth,and the difference in pH between soil layers under A1 treatment was the greatest.Increasing the amount of irrigation or nitrogen can reduce soil pH.No matter the applied amount of N fertilizer,the irrigation quantity,or irrigation fluid's pH,it mainly changes the pH of surface soil and has little influence on the pH of underlying soil.?2?Soil ammonia volatilization accumulation was positively correlated with irrigation fluid's pH,irrigation quantity and applied amount of N fertilizer.Their contribution rates to ammonia volatilization were 31.57%,4.23%and 64.2%.Compared with CK,the cumulative ammonia volatilization of A1,A2,A3 decreased by 68.34%,22.39%and-1.23%,while A5increased by 48.28%.In other words,under acidic conditions,the lower the pH of irrigation fluid,the more significant the reduction of ammonia volatilization in soil.Under the nearly neutral condition,soil ammonia volatilization increased with the increase of irrigation fluid pH,but the increase was low.Under alkaline condition,soil ammonia volatilization was the highest.In other conditions certain circumstances,the soil ammonia volatilization accumulation can be increased by 349.97%if the nitrogen application amount is doubled,and increased by 60.78%if the irrigation quantity is doubled.?3?Each treatment has no effect on soil available copper contents,but have obvious activation effect on alkali-hydrolyzed nitrogen,available phosphorus,iron,manganese and zinc contents.The correlation between alkali-hydrolyzed nitrogen and irrigation fluid's pH is not strong.In general,the content of alkali-hydrolyzed nitrogen in the soil layer of 0¹0cm under each treatment is greatly different,while there is no significant difference in the soil layer of10²0cm and 20⁴0cm.The increase of irrigation amount and fertilizer amount can improve the content of alkali-hydrolyzed nitrogen in soil,and the change of irrigation amount will have an impact on the distribution of alkali-hydrolyzed nitrogen in each soil layer.The content of alkali-hydrolyzed nitrogen in each soil layer is 10²0cm>0¹0cm>20⁴0cm under W1condition,while W2 condition is 0¹0cm>10²0cm>20⁴0cm.Different with alkali-hydrolyzed nitrogen,increasing irrigation or nitrogen application can reduce the content of rapidly available phosphorus in soil.Under each treatment.Only A1 can increase the content of rapidly available phosphorus,which is as high as 14 times compared with other treatments.Similarly,only A1 irrigation solution could increase the content of available iron.A1 also has a strong activation effect on manganese,which is 2³ times higher than A2,A3,A4 and A5.With the decrease of the pH of irrigation solution,the content of available zinc in soil increased,and there was a significant difference between A1 and A2,A3,A4 and A5.The available contents of iron,manganese and zinc in soil increased with the increase of irrigation quantity and applied amount of N fertilizer.The effects of each treatment on the contents of available phosphorus,iron,manganese and zinc in the 0¹0cm soil layer were significant,while the effects on the 10²0cm and20⁴0cm soil layer were not obvious.?4?Under the same water and fertilizer condition,the biomass of ryegrass under A2 was the largest,which was significantly different from other treatments.The increase of irrigation water could increase the biomass of ryegrass,but the excessive nitrogen application would reduce the biomass of ryegrass.