Effects Of Fertilization Treatments On The Distribution Of Soil Aggregates And Glomalin

Glomalin, a kind of soil protein secreted by arbuscular mycorrhizal fungi, is the important component of the soil organic carbon, and is related to the aggregate formation and stability. Most researches on glomalin are focused on the forest, grassland soil which contain higher organic matter. While the fertilization, influencing the physi-chemical properties of soil and microbial activity, is an important agroecosystem management, but little attention was paid to the effect of different fertilization on the glomalin in bulk soil and aggregates Fig. .We investigated the distribution of aggregates in different fertilization treatments by wet sieving method, and measured the soil organic carbon and glomalin concentration in bulk soil and aggregates. The aims are to analyze the effect of fertilization on the content of soil organic carbon and glomalin in bulk soil and aggregates, to examine the relationship among the distribution and stability of aggregate, soil organic carbon and glomalin.The results show that, although the aggregate distributions are not change under all kinds of fertilization, but fertilizer applications still impact the distribution of soil aggregates. Mainly, inorganic applications facilitate the formation of small macro-aggregates, and organic fertilizer and inorganic with low amount of organic fertilizer are favor to the formation and stability of >0.25mm aggregates, and the high amount of organic manure with inorganic fertilizer has little effect of the formation of macro-aggregates, but correspondingly increase the ratio of small aggregates in the soil.Fertilizer applications significantly increase the content of soil organic carbon and glomalin in bulk soil and aggregates. Different kinds of fertilizer have various effects on the concentration of glomalin in aggregates. Inorganic fertilizers increase the content of glomalin in lager macro-aggregate but reduce the concentration of glomalin in small macro-aggregate, and organic fertilizer was useful for the accumulation of glomalin in large and small macro-aggregates; Organic-inorganic fertilizers significantly increase the content of glomalin in large macro-aggregates, and the amounts of organic fertilizer influence the glomalin content. In small macro-aggregates, inorganic fertilizer obviously affect glomalin content detected under organic-inorganic fertilizing; and the glomalin contents in micro-aggregates and silt + clay are less affected by the fertilization.The results show that there is a significant linear correlation between the content of glomalin and soil organic carbon in bulk soil, but in aggregates scale, it does not show linear correlation of the glomalin to soil organic carbon, the distribution and stability of aggregates, The reason maybe due to the different agents which influence the aggregates formation.