Abstract:
The investigations
conducted during 2005-2010 at the Podu-
Iloaiei Agricultural Research Station, Ia i
county, have studied the influence of
different mineral fertilizers rates on wheat
and sunflower yield and soil agrochemical
characteristics. In bean-wheat-maizesunflower-
wheat crop rotation, applying
mineral fertilizers resulted in getting
mean yield increases, which varied
according to rates, between 94 and 180%
(1631- 3129 kg/ha) in wheat and between
38 and 101% (773-2063 kg/ha) in
sunflower. The mean yield increases,
obtained for each kg of a.i. of applied
fertilizer, were comprised between 11.2
and 13.6 kg grains (N80P40 - N160P80) in
wheat and between 9.2 and 9.7 kg grains
(N40P40 - N120P80) in sunflower. In the
soils from the Moldavian Plateau, which
are poor in organic matter and nutrients,
the proper use of different rotations and
fertilizer doses may replace a part of high
technological consumption, determined
the improvement in the content of organic
matter from soil and ensured better
conditions for the capitalization of
nitrogen fertilizers. On the Cambic
Chernozem from the Moldavian Plateau, a
good supply with mobile phosphorus in
wheat and sunflower crops (37-72 mg/kg)
was done in case of the annual application
of a rate of N120P80, while a very good
supply (72-91 mg/kg) was achieved at the
rate of N140P100. After 44 years of
experiences, in five year crop rotation,
fertilization of sunflower, wheat and
maize crops with high rates of mineral
fertilizers (N160P80), resulted increased
soil organic carbon content by 22, 7%
(3.5 g C / kg soil), compared to the
unfertilized control.
