Abstract:
Since 1968, at the
Agricultural Research Station of Podu-
Iloaiei, Iași County (47°12´ N latitude,
27°16´ E longitude), investigations were
conducted on the influence of different crop
structures and fertilizers on yield, erosion
and soil fertility. The paper presented the
results of investigations concerning the
influence of long-term fertilization (43
years) on some chemical characteristics of
Cambic Chernozem from the Moldavian
Plain and on the yield of wheat and maize,
placed under different crop rotations with
perennial grasses and legumes. The
objectives of this study was, to monitor
runoff, soil loss and soil chemical properties
in monocultures of wheat and corn,
compared with different rotations and
fallow land. The climatic conditions in the
Moldavian Plain were characterized by
annual mean temperature of 9.6oC and a
mean rainfall amount, on 50 years, of 553.5
mm, of which 141.5 mm during September-
December and 412.0 mm during January-
August. In the last 20 years, the mean
annual recorded quantity of rainfall was of
588.7 mm (100%), of which 369.5 mm
(62.8%) determined water runoff and soil
losses by erosion. Mean annual losses of
soil by erosion, recorded in the last 20 years,
in the Moldavian Plain, were of 0.161 t/ha
in perennial grasses in the second growth
year, 3.883 t/ha in beans, 6.369 t/ha in
maize and 6.733 t/ha in sunflower. The crop
structure, which determined, during 1991-
2010, the diminution in mean soil losses by
erosion until 1.954 t/ha/year included 20 %
straw cereals (wheat), 20% annual legumes
(pea), 20% row crops (maize) and 40 %
perennial grasses and legumes (Alfalfa +
Lolium perene). After 43 years of
experience, in the pea - wheat - corn -
sunflower rotation + reserve field, cultivated
with legumes and perennial grasses, soil
organic carbon content increased with
14.7% (2.8 C g / kg), in comparison with
wheat - maize rotation.
