Effect of N fertilizer rates and biofertilizer on productivity and quality of fodder sorghum

A field experiment was conducted at Farm of the Agricultural Faculty, Al-Azhar University, Assiut Governorate, Egypt, during successive summer seasons of 2022 and 2023 to study the effect of four nitrogen fertilizer rates (N1=30, N2= 60, N3= 90, N4= 120 kg N/feddan) (feddan = 4200 m² = 0.420 hectares = 1.037 acres) and biofertilizer (B0= without biofertilizer and B1= with Nitrobine as a biofertilizer) on productivity and quality of fodder sorghum (Sorghum bicolor L. Moench). A randomized complete block design (RCBD) in a split plot arrangement with four replications. The important results could be summarized as follows:Increasing nitrogen fertilizer rate from 30 up to120 kg N/feddan led to a significant increase in plant height, number of leaves/plant, number of tillers/plant, leaf area index (LAI) and fresh and dry forage yield t/feddan in the three cuts during the two studying seasons, as well as crude protein percentage in the first cut at both seasons and in the third cut of the second season only.The use of Nitrobine as a biofertilizer resulted in a significant increase in plant height, number of leaves/plant, number of tillers/plant, leaf area index (LAI) and fresh and dry forage yield t/feddan in the three cuts during the two studying seasons, as well as crude protein percentage in the first and the second cut at both seasons and also in the third cut of the second season only, this is compared to without biofertilizer.The results during the two studying seasons showed significant effects of the interaction between nitrogen fertilizer rates and biofertilizer on most of the traits studied and the best results were with nitrogen fertilization at rate 120 kg N/feddan with biofertilizer From the results, the study concluded that the biofertilizer Nitrobine used with nitrogen fertilization at rate 120 kg N/feddan led to increased productivity and quality of fodder sorghum.