Influencing Factors of Leaching Nutrients in Red Soils

Field lysimeters combined with long- term experiments were used to study nutrient leaching of red soils in a hilly region of Southeastern China. The effects of soil parent materials, land use, cultivation, and fertilization on leaching were investigated. The nutrient leaching was concentrated in rainy season from April to June after fertilization. Both the soil porosity and the soil water content affected the nutrient leaching process. N and K were easier to leach than P because of the stronger fixation of P by red soils. Compared with waste land and grassland, upland with peanut- radish rotation reduced the N and K leaching, and tea tree reduced the K leaching in the surface layer for the lager nutrient assimilation by plants. However, the nutrient leaching in the uplands was more than in paddy soils in consideration of the fertilizer application rate. No- tillage with stubble mulch had a lager N and K leaching ration than the conventional tillage. Below the rate of 150 kgN· hm- 2, the leaching amount and ratio of N increased with the application rate, and it decreased by addition of air- dried manure due to the change of N∶ P∶ K ratio and the decomposition of manure.