EFFECT OF NUTRIENT SUPPLAY ON GROWTH AND DEVELOPMENT OF PEPPERS IN PROTECTED CULTURE
Under optimal microclimatic conditions of protected culture, fertilizers are more effective then outdoors. Therefore rank growth and deficiency of fruit set are more frequent. Peppers — especially some of the waxy varieties — are known to react sensitively to nutrient level.
1973 to 1976 a number of experiments were carried out in glasshouses and plastic houses (in vegetative post with nutrient solutions and in peat pots). Observations on plant developement and yield were completed by laboratory plant and soil analyses.
Research work was begun by studies on symptoms of deficiency and overdosing of the most important nutritive elements. Symptoms of N, P, K, S, B deficiency and N, B, Mn, Zn, Al overdosage are described.
Effect of nutrient level on the development of young plants in peat pots was studied too. At the temperature optimum for peppers (25°C) best growth was made with 0.76 kg P2O5/m3 of the misxture used. At lower temperatures less phosphorus (0.31—0.40 kg/m3) seemed to be more effective. Optimal phosphorus level for young plants is higher than for adult ones.
Limits of salt toxicity by excess N, P2O5 and K2O were determined.
In conditions of low nitrogen level the fruit flesh occured thin, but the shape and the size of fruits remained characteristic to the variety. Addition of nitrogen led to thicker fruit flesh, but excess nitrogen doses gave extremely small fruits.