Spatiotemporal Changes of Soil Potassium in the Manure Microsites in Latosol after Application of Stylosanthes Green Manure

摘要

Introduction: Major soils in the tropics and subtropics are often poor in plant nutrients (Soil Survey Staff, 2006), especially in mountain orchard soil. Recently, during the course of cultivation in mountain orchards, organic manure is not applied or is being applied less, given the increase in price of organic manure due to the lack of organic manure resources and poor traffic. As a result, problems such as deficiency and imbalance of nutrients and soil acidification arise. Consequently, the yield and quality of the fruits in mountain areas have decreased rapidly, thereby seriously affecting the healthy and sustainable development of the local economy. The addition of organic materials, especially green manure (GM), to these soils is good way to solve the problem. Stylosanthes (Stylosanthes guianensis Sw.) possesses high animal nutritional and manure value, and has been planted widely as forage or GM crops in the tropics and subtropics (Stace, 1984; Liu, 2008). After application of GM, the nutrient concentration in the soil close to the manure site could be several times higher than the whole soil mass, thereby inducing a series of special physical, chemical, physiochemical, and biochemical reactions, which usually have a larger effect on the supply of soil nutrients and efficiency of fertilizer use (Lu, 1999); therefore, it is important in rational fertilization. The potassium content of GM makes allow its application to effectively increase soil organic matter and nutrients such as potassium, while enhancing their distribution in the soil near the manure site. Research on the spatiotemporal change of soil potassium in manure microsites in latosol after application of Stylosanthes GM could better explain the effects of GM application on the soil potassium content level in microsites, which could in turn benefit the confirmation of the distance and time of GM application. As an important reference to the rational application of GM, the present study has practical value.