Effect of soil management, pH, and fertilizers on Packham's Triumph and Josephine de Malines pears

Abstract

The effects of soil management, liming (soil pH), and fertilizers on Packham's Triumph and Josephine de Malines pears under irrigation conditions were studied. The management systems were cultivation, straw mulch, bare surface, and white clover sward. The fertilizers were phosphorus and nitrogen (on straw mulch only), potash and nitrogen (on bare surface only), nitrogen on clover sward only, and calcium as agricultural lime and nitrogen (on cultivation only). Treatment effects were expressed as yield or vigour differences between pre-trial and post-trial periods. Packham's gave similar yield of fruit whether on cultivation or straw mulch. The yield from clover sward and bare surface was much lower than from straw mulch trees. Tree vigour was best under straw mulch and similar within the other treatments. For Josephine, all treatments yielded equally, but tree vigour was best under straw mulch plots. Packham's under bare surface and receiving the highest dressing of potassium sulphate yielded better than the unfertilized trees. Josephine under straw mulch and receiving the highest dressing of superphosphate yielded better than unfertilized trees. Under clover sward, Packham's receiving no artificial nitrogen had lower yield than those receiving standard dressing of nitrogen (0.7 metric tons per hectare of ammonium sulphate). Under these conditions, there were no differences in the yield of Josephines, whether they had artificial nitrogen or not. Packham's under cultivation had similar yield at pH 5.0, 6.5, or 7.5. Josephines, however, yielded much better at pH 6.5 and 7.5 than at pH 5.0.