Combination Influences of NPK Fertilizers and Bradyrhizobium Inoculation on the Yield, Chemical Constituents and Guaran Production of Guar (Cyamopsis tetragonoloba, Taub.) Plant

Abstract

At the Experimental Farm (Ghazala Farm) of the Agric. Fac., Zagazig University, Egypt, two field experiments were conducted through the two successive summer seasons in 2019 and 2020. This was an effort to improve the guar plant’s yield and productivity. The experiment was set up as a split-plot design with NPK fertilization as the main plot and bio-fertilization as the sub-plot. The Bradyrhizobium spp. inoculation rates were (0.0, 200 and 400 g/feddan), while the NPK fertilization levels were (0.0, 75, 100, and 125% of recommended level). Ammonium sulphate (20.5% N) at 200 kg/feddan, calcium super phosphate (15.5% P2O5) at 200 kg/feddan, and potassium sulphate (48% K2O) at 100 kg/feddan were the NPK fertilization recommended rates (RR). The obtained results showed that, in comparison to control and the other levels under study, guar plants fertilized with 125% RR significantly increased yield components as well as total carbohydrates content, and NPK percentages in seeds and guaran production. Additionally, compared to the control and lowest inoculation rates of Bradyrhizobium, the maximum inoculation rate (400 g/feddan) considerably recorded the highest values of all the aforementioned parameters. The majority of the study’s findings demonstrated that fertilized guar plants with 125% RR of NPK fertilization, together with 400 g/feddan of Bradyrhizobium inoculation rate, might aid to improve guar plant (Cyamopsis tetragonoloba Taub.) yield, chemical constituents and guaran production.