Abstract:
The influence of long-term
fertilization and irrigation on wheat and
maize yield and soil fertility was studied at
the Agricultural Research and Development
Station of Podu-Iloaiei since 1980. These
experiments were carried out on a 10 %
slope field, on a Cambic Chernozem with
clayey loam texture (423 g clay, 315 g loam
and 262 g sand), a neuter to weakly acid
reaction and a mean nutrient supply. The
mean annual rainfall amounts, recorded in
the last 28 years, were higher, with values
comprised between 12.7 and 279.2 mm,
compared to the multiannual mean on 80
years (542 mm) in 16 years, and lower by
25.3 - 236.7 mm in 10 years. Annual
application of rates of N160 P80, in a fouryear
crop rotation (soybean-wheat-sugar
beet-maize) + a reserve field, cultivated
with legumes and perennial grasses,
determined the accumulation of a reserve of
mobile phosphates of 78 mg/kg soil. Under
irrigated, a good plant supply with mineral
elements and the increase in the content of
organic carbon from soil were done by
applying the rate of N80P70+ 30 t/ha manure.
Nitrogen and phosphorus fertilizers,
although applied at high rates (N130 +100
P2O5), could not prevent the decrease in
organic carbon content from soil.
