OPTIMIZING NITROGEN INPUT AND HARVEST TIME TO MAXIMIZE THE MAIZE FODDER YIELD IN PUNJAB, PAKISTAN

Appropriate nutrient management and harvesting date are the main and quickest means for increasing maize production. A field experiment with three nitrogen fertilization rates (N1= 50; N2= 100; N3= 150 (kg ha^-1) and three harvest dates (H1= 50, H2= 60 and H3= 70 DAS) was carried out at the Agronomic Research Area, University of Agriculture, Faisalabad to predict the response of maize (Zea mays L.) fodder yield and its quality attributes to optimal nitrogen input rates and harvest dates. The results showed that increase in nitrogen fertilizer input resulted in significant (P ≤ 0.05) increase in yield and quality traits. Yield attributes as plant height (179.40 cm), stem diameter (3.59 cm), leaf area plant^-1 (3755 cm^2), dry matter (33.44%), dry matter yield (17.68 t ha^-1) and green fodder yield (71.32 t ha^-1) were significantly increased with nitrogen input of 150 kg N ha^-1. Among nitrogen input rates, 150 kg N ha^-1 level was also responsible for highest crude fat (3.09%), crude protein (11.48%) and crude fiber (34.21%) except ash contents (10.17%) compared to other nitrogen treatments. Twenty days delayed for harvest proved to be best for increasing growth and quality characters of maize plants. The interaction between nitrogen rates and harvest dates was found to be highly significant except for plant height, dry matter percentage and crude protein. Nitrogen input of 150 kg N ha^-1 with 70 DAS harvest date (N3 × H3) significantly improved the stem diameter (5.11 cm), leaf area plant^-1 (4108 cm^2), dry matter yield (21.35 t ha^-1), green fodder yield (83.87 t ha^-1) and crude fiber (37.21%) while crude fat (2.47%) and ash (9.17%) contents were decreased. In conclusion, on the basis of growth and quality parameters, the nitrogen application at 150 kg N ha^-1 and harvesting time (70 DAS) was the suitable option to attain highest maize fodder yield.