Agriculture Reference
In-Depth Information
that includes all technological operations for growing winter wheat. The prices for fuel
fertilizers and pesticides were in accordance with the real prices for these products in
the Republic of Moldova. The yield of wheat was the same for all treatments (4.2 Mg/
ha); however, the costs were different. The same wheat yield can be achieved at less
cost following the alfalfa-ryegrass mixture compared with winter wheat follow-
ing maize silage. By using minimum tillage, it was possible to save $US 26.1/
ha on fuel after both preceding crops. When sown after silage maize, additional
expenditures for weed, pest, and disease control amounted to $39.6/ha and those
for mineral N fertilizers to $76/ha. Thus, the total saving by sowing winter wheat
after alfalfa-ryegrass mixtures in the third year after the first cut amounted to
$115.6/ha. These savings can be realized only by adopting crop rotation; otherwise,
the money saved from minimum tillage ($26.1/ha) is not enough to pay for chemical
weed, pest, and disease control ($39.6/ha). Conservation farming can be effective
by using an optimal combination of minimum tillage and a good crop rotation.
9.4
CONCLUSIONS
1. The leveling off or declining yields of most crops, both on average for the
Republic of Moldova and in the long-term field experiments, necessitates
reappraisal of the existing farming systems. Thus, there is a strong need for
a paradigm shift toward sustainable intensification based on more intensive
recycling of nutrients and energy within each farming system, and using
predominantly local, renewable sources of energy. This strategy would be
more environmentally friendly, and achieve healthy soils and healthy peo-
ple dependent on it.
2. The neglect of crop rotations and soil fertility during the specialization and
concentration of agriculture are attributed to the higher efficiency of chemi-
cals in continuous monocultures relative to more diverse crop rotations,
stimulated by cheap fuel and its derivates, as well as ignorance of the dam-
age to the environment and public health.
3. High-yielding varieties of winter wheat are more efficient in crop rotation
than in continuous wheat. These varieties require additional nutrients, which
are derived not from high rates of mineral fertilizers but by depletion of the
inherent soil fertility.
4. Minimum soil tillage does not reduce the yield of field crops relative to
moldboard plowing; however, it minimizes risks of soil erosion, reduces the
rate of mineralization, and decreases losses of SOM.
5. Mineral, organo-mineral, and organic systems of fertilization all increase
yields of field crops; however, their influence on soil fertility vary. Organic
and organo-mineral systems of fertilization improve inherent soil fertility
vis-à-vis
the use of mineral fertilizers.
6. Irrigation, especially in combination with fertilizers, increases crop yields
but accelerates the loss of SOM from the entire soil profile.
7. No single factor of intensification used alone can compensate for the annual
losses of SOM from arable land. However, integration of crop rotation with
perennial legumes and grasses, fertilization with liberal use of FYM, and
