V. Rizzo

Yield and quality of durum wheat (Triticum durum Desf.) under continuous cropping after nine years of straw incorporation

Abstract The aim of the long-term research described is to determine the effects of straw incorporation, with or without the application of increasing doses of nitrogen (50-100-150 kg ha -1 ) and 500 m 3 ha -1 of water, on the yield and quality of durum wheat under continuous cropping. The experiment was begun in 1978 at Foggia (Southern Italy). Two varieties of durum wheat, cv. Valgerardo and cv. Appulo, have been grown. The effects of the treatments were greatly influenced by seasonal weather and by the specific behaviour of cultivars, which differed in their ability to use the nitrogen applied. The trial has given good results from straw and stubble incorporation, in comparison with burning, at present, widely practiced by farmers. Nitrogen fertilizer applied to crop residues was not very beneficial; the yields from the treatment with N only as a top dressing were almost the same of those from the treatments which received the lowest N dose (50 kg ha -1 , with or without water, while the highest ones (100 and 150 kg ha -1 ) gave lower yields, not compensated by a corresponding improvement of grain quality.