Articles
YIELD AND QUALITY OF EARLY HEAD LETTUCE IN RELATION TO PHOSPHATE FERTILIZATION AND PHOSPHATE STATUS OF THE SOIL
This increases the risk of P leaching to the environment.
Reliable data for an adjustment of the phosphate advice fail.
So new P experiments were necessary.
In 1996 research on phosphate fertilisation was started with leek, carrots, cauliflower and head lettuce as pilot crops.
The optimum P status in the topsoil related to these different crops needs to be investigated, and optimum P rate at different soil P’s has to be known.
Data of total and marketable yield, P uptake during the growth and at harvest, P removal and root development were collected.
The field experiments serve tools to validate a mechanistic simulation model that describes the P requirement of vegetable crops.
This model serves as a tool for deriving new fertilisation schemes
This paper describes and discusses the results of early head lettuce (LactucasativaL.var.capitata), cultivated at different levels of P status of the soil, combined with different rates of P fertiliser dressing.
In the years 1996–1998, research was carried out to study the influence of a range of P fertiliser dressing at 12 locations with different types of soil.
The research to the influence of different levels of the P status of the soil was done at the PAV location in Lelystad with the following objects: four levels of the P status of the soil; two levels of P fertiliser dressing; cultivation with and without crop covering (agryl).
The optimum P fertiliser dressing is strongly linked with the P status of the soil and the cultivation method.
Because of the strong phosphate need of lettuce and the rather immobility of phosphate in the soil, there is a big yield response of phosphate fertilisation on soils with a low P level.
At the cultivation of early head lettuce, the adjustment to an environmentally sound P advice should have consequences for the yield.