Public concerns over the potential environmental hazards of intensive agriculture have renewed an interest in the low-input nitrogen (N) fertilization practices for wheat (Triticum aestivum L.). A two-year study (2001 and 2002) was conducted to determine the infl uence of cropping intensity, namely the low-N (67 kg N ha-1) and high-N (194 kg N ha-1) input levels on the grain N and phosphorus (P) content, phytate-P (phytic acid and its salts), hectoliter weight and grain yield of three bread wheat cultivars widely grown in Croatia. Growing conditions significantly affected grain yields averaging 6641 kg ha-1 in the fi rst growing season and 8295 kg ha-1 in the following year. Despite an associated increase in the 1000-grain weights, the use of the low-N fertilization brought about a significant decrease in grain yield, hectoliter weight and grain N content in all cultivars by an average of 18.1%, 1.5% and 22.6%, respectively, when compared to the high-N fertilization level. The reductions in grain N content were consistent in both years regardless of variations in grain yields among three tested cultivars. Grain N content under the low-N fertilization averaged 17.1 g kg-1 only, which may limit its use for breadmaking. In contrast, grain P content was not affected by N fertilization or growing season and averaged 4.70 g kg-1 across all treatments. Absolutely small, but significant differences existed among cultivars for total grain P content, of which about 80% was in the form of phytate-P. A negative correlation between the 1000-grain weight and P content was found because of tendency toward lower P content in heavier grains. When compared to the high-N input, the low-N fertilization practices for wheat crop were associated with a significant decrease in grain yield and grain N content in all cultivars, but had no effect on grain P content regardless of cultivar.

wheat; quality; cultivar; nitrogen; phosphorus; cropping intensity

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia