Nutrient cycling and soil fertility in the grazed pasture ecosystem

摘要: Publisher Summary This chapter reviews the cycling of nutrients within pasture soils. The major emphasis is on central role grazing animal in influencing soil fertility, particularly dung and urine patches. In addition, progress reviewed that has been made modeling systems. Nutrients are partitioned differently between urine, with K being excreted mainly urine; P, Ca, Mg principally N S both forms. returned excreta can be inorganic organic forms, depending particular nutrient considered. For some (e.g., P S) significant mineralization ingested forms occurs during passage through animal, whereas much readily available urea form. From present knowledge inputs losses for grazed system an understanding pathways flux key measurements, simple mass balance models various systems constructed. Such have used to calculate site-specific maintenance fertilizer requirements pastures based amount required replace fixation leaching) by transfer products.