Effects of the form of nitrogen on the growth and nutrient uptake of tomato, groundsel and fat-hen

Abstract

The effects of forms of nitrogen on the growth and nutrient content of tomato (Lycopersi- con esculentum Mill cv. Ailsa Craig), fat-hen (Chenopodium album L.) and groundsel (Senecio vulgaris L.) were investigated under glasshouse conditions using the nutrient film technique and pot experiments in both pure and mixed stands. Growth of all species was reduced when ammonium or urea was the only source of N. Fat-hen was most and groundsel the least sensitive species. P was the element reduced by the greatest amount in groundsel roots with ammonium and urea-N. The growth reduction shown by fat-hen under ammonium-N was associated with reduction in its ability to take up K. Fat-hen shoot concentrations of K and Mg were greatly reduced as its density in mixtures was increased and this was more pronounced under ammonium-N. The results are discussed and their possible significance in competetive relationships noted.