Investigations on the influence of long-term fertilization on wheat and sunflower yield and soil fertility in the Moldavian Plain.

The investigations conducted in stationary experiments, at the Podu-Iloaiei Agricultural Research Station, which were set up in 1967, under non- irrigated, have followed the influence of mineral fertilization on wheat and sunflower yield and on the evolution of soil physical, chemical and biological characteristics. In bean-wheat-sunflower-wheat-maize crop rotation, applying mineral fertilizers during 2005-2008 has resulted in getting mean yield increases, which varied, according to rates, between 41 and 94% (767-178 kg/ha) in sunflower (N40P40-N120P80) and between 89 and 146% (1658-2718 kg/ha) in wheat (N80P80-N160P80). The mean yield increases, obtained for each kg of a.i. of applied fertilizer, were comprised between 8.4 and 8.9 kg in sunflower (N80P80-N120P80) and