RESEARCHES ABOUT THE PHOSPHORUS REGIME FROM AGRICULTURAL ECO-MEDIUM IMPROVED BY THE SEWAGE SLUDGE

Together with other chemical elements: macronutrients and micronutrients,phosphorus (P) take active part in plant nutrition. The application of waste sludge increased P contents in both soil and plants. The study of macronutrient was done in terms of sludge doses increased from 0-50 t.ha-1, with and without chemical fertilizers. For white luvic-soil sensitive growth were observed with near- normal oscillations of the average concentrations of total P. Mobile forms of phosphorus have seen significant growth, with coefficient of correlation between 0.309 for maize, the wheat 2 0.152, 0.691** for soybean and 0.923*** for wheat 4. However, phosphorus ions (H2PO4-) were specifically absorbed by the crop: maize, winter wheat and soybeans. The correlations obtained between P concentrations in plants with sludge doses, showed increases in quite all cases:statistically ensured in maize leaves, flowering period (0.776***), insignificant for wheat 2 and soybean, except wheat 4 (-0.283), and partially decreases in maturity period (in grains), insignificant for wheat 2 and 4, significant for soybean (-0.643**), and one exception for maize with r = 0.700**