A new approach has been developed for forecasting the fertiliser requirements of each of the many vegetable crops on the widely different soils on which they are grown.
The responses of the various vegetable crops to N, P and K fertilisers were defined and compared with those of agricultural crops in detailed experiments at Wellesbourne. Simple models were developed for fertiliser response which enabled this information together with the results of past experiments on agricultural crops on different soils to be used to forecast the responses of each of the vegetable crops on a wide range of soils. Predictions made in this way for P and K responses were, with notable exceptions, in approximate agreement with the results from over 200 independent fertiliser experiments carried out on various sites throughout the U.K. and Eire.
The work suggests that the levels of P and K maintained in many vegetable soils in- the U.K. are far higher than is needed and, in consequence, there may be much waste of fertiliser. On the other hand, it appears that most vegetable crops require nitrogen fertilisers on all soils and that present levels of application are inadequate in some cases. There is also scope for improving the effectiveness of applied fertilisers as the recoveries of applied nutrients were very low.
Broadcast applications of nitrogen fertiliser, on occasions, depress seedling emergence and thereby reduce yields. Ways of overcoming these effects have been found.