There is an increasing need to improve the fodder productivity of the common forage crops grown in the summer season in Egypt. Fertilizer management is among the common cultural practices that have a direct influence on the forage yield and growth attributes.
This study was carried out during two successive summer seasons (2014 and 2015) in Egypt and aimed to investigate the variations in yield and some agronomic characteristics of three successive cuts of five fodder pearl millet cultivars under integrated use of nitrobine bio-fertilizer with different doses of mineral nitrogen fertilizer. The studied fertilization treatments were; 60 and 90 kg mineral N fed-1 alone and the same doses accompanied with nitrobine bio-fertilizer application. In addition to fresh and dry yields (ton fed-1), and dry matter content (g kg-1), the following agronomic characteristics were evaluated; plant height (cm), stem diameter (mm), number of leaves per plant, leaf area per plant (cm2), number of tillers (m-2) and leaf/stem ratio. A pronounced response in almost all the studied parameters to the different fertilization treatments was achieved for the three investigated cuts for both growing seasons. The application of bio-fertilizer accompanied with 60 or 90 kg N produced the highest significant fresh and dry yields. No significant variation was detected among the tested fertilizer treatments for the dry matter accumulation of the 1st cut, while the application of 60 kg mineral N fed-1 in addition to bio-fertilizer accumulated the highest amount of dry matter for the 2nd and 3rd cuts. Similar to the yield results, the integration of bio-fertilizer with 60 or 90 kg mineral N fed-1 resulted in better growth attributes. Giza 1 and Giza 2 proved to be high yielding cultivars with superiority in the studied growth attributes. Meanwhile, Shandaweel 1 and Sharq El Owainat were inferior to the other cultivars. Investigating the three successive cuts revealed that the values for all the studied parameters were the highest in case of the 1st cut and then gradually decreased till reaching the lowest values for the 3rd cut. It is recommended to integrate nitrobine bio-fertilizer with low doses of mineral N fertilizer in the production of fodder pearl millet.
Keywords: Pearl millet, Forage, Bio-fertilizer, Yield, growth attributes.