Reduction in phosphatic fertilizer by means of pre-transplanting application.

摘要

Phosphorus availability was improved for cabbage by applying phosphorus before transplanting. When potassium, ammonium or sodium phosphate monobasic solution was applied to cabbage seedlings before transplanting, the weight of the cabbage head was the same as that when using the usual fertilizer system. Phosphorus uptake increased when 40% or 20% P was applied before transplanting, especially during the early stage after transplanting. Consequently, 30-60% less of the phosphatic fertilizer was required, and phosphatic availability was improved 2.5 times. However, no effect was observed when controlled-release fertilizer was applied. This high phosphorus availability was due to high phosphorus absorption resulting in a high growth rate during the early stage, as well as less phosphorus fixation in the soil. However, excess phosphorus often induced salt injury such as chlorosis and leaf burn.