The Effects of Different Manurial Treatments on the Yield and Mineral Composition of Winter Lettuce

Abstract

SummaryLettuce were grown during the winter of 1957–58 on the plots of a long-term manurial experiment in which the treatments had been applied to each crop from 1954 to 1957. Three rates of each of the three nutrients N, P and K were applied either with or without farmyard manure (20 tons per acre per crop) in a 33 × 2 factorial design.The mean yield from the plots which received farmyard manure (FYM) together with fertilizers was more than twice that from the plots which received fertilizers alone; the extra yield came from the greater number of lettuces that reached marketable condition on the former plots and not from an increase in the size of the plants. The date by which 50% of the plants that eventually reached marketable condition had been cut was almost 8 days earlier for the FYM plots than for the no-FYM plots. The different rates and combinations of fertilizers, when applied with FYM, did not produce different yield effects.In the absence of FYM, applications of sulphate of potash and superpho...