Phosphorus Adsorption Characteristics Of Cinnamon Soil And Growth Of Cucumber Under Different Water And Fertilizer Conditions

Thosphorus content in soil can not meet the demand of crops growth,so phosphate fertilizer input is one of the necessary measures to ensure high yield of crops.Excessive fertilization leads to the accumulation and leaching of phosphorus in soil.The adsorption and desorption characteristics of phosphorus in different soil layers of cinnamon soil which came from Yongji City of Yuncheng City,Shouyang County of Jinzhong City,Taigu County of Jinzhong City,Zhangzi County of Changzhi City,and Xiaodian District of Taiyuan City were studied with isothermal adsorption and desorption test.The adsorption kinetics of phosphorus in soil was studied at initial exogenous phosphorus concentration of 100 mg/L.Another experiment was conducted to study nutrient absorption in cucumber and plant,cucumber yeild,and etc,in green house under different phosphorus and irrigation levels.The treatments were: conventional fertilization + irrigation(T1),80% conventional fertilization + conventional irrigation(T2),conventional fertilization + 80% conventional irrigation(T3),conventional fertilization + conventional irrigation + biochar(T4),80% conventional fertilization + 80% conventional irrigation + biochar(T5).The yield and nutrient content of cucumber,and irrigation water productivity(IWP),phosphate partial productivity(PFPP).The main findings were as follows:(1)The amount of phosphorus adsorption and of phosphorus desorption in different layers and areas of soil increased with the increasing of initial exogenous phosphorus concentration,the adsorption amount increased with the increasing of soil depth,and the desorption amount decreased with soil depth.The adsorption process of phosphorus could be well fitted with Langmuir equation in cinnamon soil of different regions and layers.The results of phosphorus isothermal adsorption in different layers and regions soil could be well fitted with quasi-secondary dynamics.The maximum value of qe appeared in the 40-60 cm layer in Zhangzi County,and the minimum value appeared in 0-20 cm layer in Shouyang County.The maximum and minimum values of k value appeared in 40-60 cm and 0-20 cm layers in Yongji City,respectively.(2)The results showed that reduction of phosphate fertilizer application based on the amount of phosphate fertilizer applied by farmers did not reduce cucumber yield.Cucumber yield ranged from 92,910 to 98,624 kg/hm2,the yield of T3 was the largest,the yield of T5 was the smallest,and there was not a significant among the treatments.Reducing water and phosphate fertilizer rates did not affect the nutrient content in cucumber.In addition,reducing water and phosphate fertilizer could also increase PFPP and IWP.PFPP and IWP showed T5 was the largest and T4 was the smallest.Cucumber nutrient surplus appeared in every treatment.T2 had the least amount of nutrient surplus.PFPP and IWP showed T5 was the largest and T4 was the smallest.In summary,the maximum values of fitting parameters Qmax,K,MBC and qe appeared in cinnamon soil of Zhangzi County,which indicated that the adsorption of phosphorus in cinnamon soil in Zhangzi County was the strongest.Reducing the amount of fertilizer and irrigation did not affect cucumber yield,cucumber and plant nutrient content.