Responses of peach seedlings in sand culture to factorial combinations of nitrogen, phosphorus, and sheep manure

Abstract

A factorial experiment was done on Elberta peach seedlings growing in sand culture to test tree response to applied solutions of calcium nitrate and sodium dihydrogen phosphate, and to sheep manure which had been mixed throughout the sand before planting. Results showed that the phosphate and sheep manure treatments exerted a more pronounced influence on seedling growth and leaf nutrient composition when harvested after 9 weeks than did the nitrogen treatments. In the absence of sheep manure, seedling growth was increased by increasing the phosphate supply to the maximum tested (64 p.p.m. P). A strong, negative interaction was found between phosphate and sheep manure treatments in both seedling growth and leaf composition data, and it is concluded that the sheep manure served as a rich source of phosphate in this situation. In addition, application of sheep manure (except in the presence of 64 p.p.m. P) apparently increased uptake of N, P, K, Ca, and Mg by the seedlings, and also increased the concentrations of Ca, K, and P in the leaves. Other results relating to leaf composition are discussed and it is suggested that a Ca/Mg antagonism was operative.