Efeito de rochagem, vinhaça e plantas de cobertura no desenvolvimento do feijoeiro (Phaseolus vulgaris L.) e em atributos químicos do solo
Abstract
The Brazilian territory is constituted mostly by nutrient-poor soils. To keep the
Brazilian agricultural activity is necessary to import and apply high amounts of
fertilizers, which tends to aggravate the imbalance in the trade balance. Thus,
rocks containing reasonable amounts of nutrients may be an alternative to
supply the essential elements for agricultural use. But this practice has
limitations, including the slow solubilization of the minerals present in the rock,
which limits the release of nutrient amounts required by plants, especially the
short cycle. The study aimed to evaluate changes in the chemical attributes of
an Oxisol, in which the bean crop (Phaseolus vulgaris L.) occurred in
succession to cover crops and the application of vinasse and remineralizer
(basalt powder). The essay was conducted in a greenhouse and the
experimental design was a randomized block in a factorial scheme 4x4x2, with
three replications, and sampling in four times (0, 45, 90 and 110 days). Four
doses of basalt powder (0, 2, 4 and 8 t ha-1) and two doses of vinasse (0 m3 ha-
1 and 200 m3 ha-1) were applied and four types of coverage were adopted:
fallow (control), crotalaria (Crotalaria juncea L.), millet (Pennisetum glaucum (L.)
R. Brown) and brachiaria (Urocloa cv. ruziziensis Germain & Evrard). The
variables evaluated were: the plant height (h), dry mass, chlorophyll relative
index Falker (ICF), specific leaf area (IAF), levels of macronutrients (N, P, Ca,
Mg and S total) on the leaves of the bean, and soil organic matter (MOS)
content, pH in CaCl2, potential acidity (H+Al), sum of bases (SB), cation
exchange capacity (CTC), bases saturation (V) and P, K, Ca, and Mg contents
of the soil. The association of vinasse and rates of remineralizer increased
thebiometric parameters. The combination of rates of remineralizer and cover
plants promoted differences in foliar macronutrient levels, with satisfactory
levels of sufficiency to the bean, in the stage assessed. The application of vinasse provided lower rates of macronutrients accumulation in common beanin
relation to treatments without vinasse. The use of remineralizer showed low
response in chemical soil attributes, with values of pH, V and CTC lower than
the initial ones. Cover crops showed no significant effect on pH and V, with a
small decrease in H+Al, mainly in the braquiaria. The application of vinasse
provided significant increases in chemical attributes V, pH and decreased H+Al.
The pH values increased until 45 days of incubation (DAI), but with bean
cultivation they decreased and were close to its initial values. On the other
hand, the H+Al decreases until the bean planting, but tended to initial values
after 45 DAI. The bean cultivation also decreased V. Interactions showed little
effect of the associations on the evaluated variables, but the association of
remineralizer with vinasse stood out for its effect on the variables pH, H + Al
and V. The vinasse application was the most influential factor on the
macronutrientes of the soil, presenting lower concentrations of these in the soil
when applied, except for K. It is concluded that the use of cover plants with the
application of remineralizer is little advantageous to increase the solubilization
of nutrients contained in the remineralizer, although the amount absorbed by
the cover plants has not been evaluated.