SOME RESPONSES OF CUCUMBERS AND LETTUCE, GROWN IN A PEAT SUBSTRATE, TO PHOSPHATE AND LIME

Two crops of cucumbers, followed by one of winter lettuce, were grown in beds of peat with 6 levels /0.125 – 4.0 kg m^-3/ of superphosphate /18% P₂0₅/ in factorial combination with two levels of lime /pH 6 and 7/. The yield of cucumbers increased and fruit development improved with applications of superphosphate of up to 2 kg m^-3. Heavy liming /pH 7/ affected the second crop adversely by reducing the yield and increasing the proportion of poorly developed fruit.
Maximum yield of lettuce was obtained at pH 6 by applying superphosphate at 2 kg m^-3. Liming to pH 7.2 markedly depressed the yield and proportion of hearted lettuce, and even where superphosphate was applied at 4 kg m^-3 the yield was 1.9% lower than at pH 6. With both cucumber and lettuce, the yield was closely related to the phosphorus content of the leaves up to values of about 0.6% P.

Symposium on the Use of Fertilizers in Protected Vegetable Production

P. Adams, G.W. Winsor

https://doi.org/10.17660/ActaHortic.1984.145.10