| Abstrakt: |
Research conducted on sterile dumps resulting from surface mining of lignite, have shown that in the waste dump restoration process, the main issues are raised by the nonuniformity of texture, extreme textures, lack of structure, low content of organic matter, the deficiency in macro (NPK) and micro (Cu, Zn, Fe, Mn) nutrients and low biological activity. Most experiments with fertilizers revealed that the maximum yield was achieved in variants fertilized with high doses of organic fertilizers, in addition with mineral NPK. Fertilization with farmyard manure (40 t/ha) leads to increasing of corn, sunflower and peas yield with 198, 155 and 26%, while the same dose of fertilization with compost increase the yield with 216% for the maize, 188% for sunflower and 48% for peas. The same doze of farmyard manure in addition with N100P80K80 increases production with 227% for maize, 168% for sunflower and 87% for peas. Applying compost in addition with N100P80K80 increase yield with 324% for maize, 187% for sunflower and 62% for peas, offering the highest yield. The compost was obtained from manure and coal powder, and, at the end of the composting potassium humate extracted from lignite was added. Organo-mineral fertilizers with nitrogen on lignite support led to yield increasing from 90 to 120% for corn, with 60-80% for sunflower, and with 50-70% for peas. Liquid fertilizers based on humates obtained from lignite with a complex matrix containing macro-nutrients (NPK) and micro-nutrients (Cu, Zn, Fe, Mn, B) increased production of corn by 30-80% and those of alfalfa with 20-80%. Fertilization with four types of liquid fertilizers led to significant increase of the nitrogen content, the decrease of potassium content, and did not provide statistically significant changes in phosphorus, Cu, Zn, Fe and Mn content in the alfalfa leaves. The high variability of soil content in humus, total nitrogen, phosphorus and potassium in mobile forms, does not allow to consider that the fertilization system has led to significant changes of these element level in the soil. [ABSTRACT FROM AUTHOR] |
