| Abstract |
This work was carried out to assess the influence of the major macronutrients (nitrogen, phosphorus and potassium) on soil fertility, using the biological method (Mitschelrlich) and how to test the maize (Zea mays). For this test was carried out in pots in semi-controlled conditions in a greenhouse of Agronomic Research Institute in Chianga - Huambo, using as substrates the ferralsols red and ferralsols yellow. Five were established (5) treatments (T0: Simple soil''Testemunha''; T1: soil without nitrogénio''0 + P2O5 + K2O'', T2: without phosphorus Solo''N + 0 + K2O''; T3: without potassium soil''N + P2O5 + 0'' and T4: Full''N + P2O5 + K2O'') with four (4) repetitions in each. The experimental design was completely randomized blocks. The variables evaluated were: plant height, stem diameter, root length, fresh weight and dry weight of the plant and visual symptoms of nutrient deficiencies. The data were processed using the statistical package Infostat see. 2008; where simple classification variance analysis was made (ANOVA) and means of comparisons, for each of the parameters analyzed. According to the results it should be noted that generally the no phosphorus treatment (T2: Solo + N + 0 + K2O) and the control (T0: Solo + 0 + 0 + 0) showed less development in the majority of parameters assessed, while the best results in both soils were achieved in T1 T3 and T4. It has been clearly shown that the phosphorus (P2O5) is the element that is the main limiting factor of agricultural productivity ferralsols.
Key-words: Soil fertility, Nitrogen, Phosphorus, Potassium, Agro productivity. |
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