Cabbage Plant Responses to Residual Phosphorus and Potassium in the Soil and to Band‐Applied Concentrated Superphosphate and Potassium Chloride Fertilizers1

Abstract

AbstractFertilization with P and K should be adjusted to supplement the available residual P and K in the soil to supply sufficient nutrients for crops. The objective of this study was to determine the responses of cabbage (Brassica oleracea (L.) Capitata group, cv. King Cole) plants to levels of residual P and K in the soil from previous applications of concentrated superphosphate (CSP) and potassium chloride (KCl) and to banded CSP and KCl fertilizers at planting. Cabbage plants were grown in a Honeoye fine sandy loam soil (fine loamy, mixed, mesic Glossoboric Hapludalf). Main plots were arranged in a factorial combination of four levels of residual P in the soil from CSP times four levels of residual K in the soil from KCl applied during 1963 through 1972. Banded fertilizer treatments of (i) no CSP or KCl, (ii) CSP, (iii) KCl, and (iv) CSP plus KCI were applied at planting time in each main plot in 1973 and 1985. At harvest, the yields of whole heads and of burst heads were measured and the concentrations of P, K, Cl, Na, Mg, S, N, Zn, Mn, Fe, and Cu in the heads were determined. Increasing the level of residual P in the soil increased the concentration of P from 3.0 to 3.8 mg g−1 dry weight in the heads in 1973, and from 2.6 to 3.4 mg g−1 dry weight in the heads in 1985. Increasing the level of residual K in the soil increased the concentration of K from 24 to 32 mg g−1 dry weight in the heads in 1973, and from 22 to 26 mg g−1 dry weight in the heads in 1985. Applications of KCl during 1963 through 1972 increased the concentration of Cl from 2.0 to 3.4 mg g−1 dry weight in the heads in 1973, but did not affect Cl in the heads in 1985. Increasing the level of residual P in the soil up to 30 kg ha−1 in 1973 and to 21 kg ha−1 in 1985 increased the yield of heads. Banded CSP increased the yield of heads at the lower levels of soil P but not at the highest level. Increasing the level of residual K in the soil or banded KCl fertilizer, or both, increased the yield of heads but also increased the percentage of burst heads. Heads of cabbage plants with the highest yield had concentrations of P and K of 3.2 and 30 mg g−1 dry weight, respectively, in the heads; however, a concentration of K of over 26 mg g−1 dry weight caused excessive burst heads.