Preliminary Study on Potassium Leaching Characteristics of Different Soils

A soil leaching column experiment was conducted to investigate K leaching from various soils and to reveal the relationship between K leaching and soil properties.The results showed that under the light rain(87 mm),the soil texture was the main factor in determining K leaching for the soils without application of K fertilizer.The lighter the soil texture,the greater the amount of the K leached.While under the heavy rain(435 mm),soil available K was the main factor in determining how much K could be released from the unfertilized soils.When 200 mg/kg K was applied to the soils,both the content of silt fraction and slowly available K(SAK) were the main factors influencing K leaching under the light rain(87 mm).As the content of soil silt or the SAK increased,the K leaching from the soil decreased.But soil total K and SAK were the main factors in determining K leaching under the heavy rain(435 mm).When the rain fall was very higher,the apparent K fertilizer leaching ratio(AKLR) within 2 h was negatively correlated to content of soil silt.However,AKLR within 24 h was negatively correlated to pH,silt,total K,SAK and feldspar content in soils,and the silt and total K content were more closely related to AKLR than other factors.