Agriculture Reference
In-Depth Information
one node of bushing under the acute angle to the main shoot, forming as a result of
a loose bush. Every year new shoots grow in this bush, and each has its own node of
bushing out. In their turn, new shoots grow from those nodes, and the bush increases
in its volume, but it remains loose, because new shoots after coming out of the ground
stand not far from each other. Loose-bush gramineous plants have denser root rosette
than rhizome species.
The choice of gramineous loose-bush component is based on its capacity to form
the dense sod and to replace legumes. This biological peculiarity of the loose-bush
gramineous plant provides for a possibility to evaluate the selection sample of clover
in the tough conditions of a phytocenosis.
Gramineous and legume grasses have different demand for warmth, light, and nu-
trients. Legumes absorb larger amount of calcium, manganese, and chlorine from soil,
while the gramineous plants exceed legumes in the uptake of phosphorus and silicon.
Calcium and chlorine are present mainly in the lower layers of soil with limestone
streaks coming from the mother rock, and legume grasses with long roots can better
absorb them from these layers. Due to nodule bacteria living on legume roots, the
gramineous plants are better supplied with nitrogen. At the expense of their dying out
roots, they supply the components of gramineous grass stands with nitrogen nutrition.
The process of bushing out in gramineous plants usually begins 1-1.5 months
after the emergence of shoots over ground. The formation of shoots happens at the
expense of photosynthesis in the green parts of the plants and not at the expense of
reserve substances. In natural pasture plant communities, the loose-bush gramineous
plants using their sod-forming capacity can replace the legume component (especially
red clover, bird's foot trefoil, sainfoin). Thus, for the evaluation of their competitive
ability, legumes should be sown with such gramineous plants. This biological trait of
gramineous plants provides a possibility to evaluate the legume component in tough
conditions.
Evaluation of legumes in grass mixtures is fulfi lled on the quantity of both shoots
per plant in the fi rst year of life and survived plants per square measure throughout the
trial. If in the pure crop the number of shoots reaches 12-15 dependent on the sample,
in the mixture with gramineous plants the number of shoots per plant does not exceed
3-5. The number of fl owering shoots per stem reduces from 7-10 in the pure crop to
2-3 in the mixture.
The optimal proportion of legume component in natural conditions of an ecosys-
tem (i.e. under ideal ratio of grasses on pastures) should be 40-50 percent [2].
If the sample has withstood the test in comparison with the standard as a pure crop
and as an individual plant on a complex set of traits, but received low marks for com-
petitiveness (9-grade international system), it will be classifi ed unfi t for the formation
of a meadow-pasture cultivar. However, it can be used as a basic material for cultivars
of fi eld fodder production.
Evaluation of samples in phytocenotic selection on competitiveness includes reg-
istration of number of legume shoots, height of plants, number of generative organs,
and number of seeds in infl orescence. According to the procedure adopted by CMEA
countries [6-8], the competition capacity in grass stands is determined by the follow-
ing 9-point system:
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