Nitrogen enhanced sorghum morpho-physiological activity, and antioxidant capacity

Imbalanced mineral nutrition and scant information about nitrogen (N) in plants may result in reduction in sorghum morpho-physiological activities. However, farmers use higher or lower fertilizer doses regarding sorghum growth and yield. This study was undertaken to determine the response of sorghum morpho-physiological activities to different rates of nitrogen (N) during two growing seasons of 2017 and 2018. The treatments were consisted of a factorial combination of three N levels (N1 = 0 kg N ha − 1 , N2 = 150 Kg N ha − 1 , and N3 = 300 kg N ha − 1 ) and two varieties (V1 = CFSH30, and V2 = Siyong 3180). Treatments were arranged in a randomized complete block design with three replicates. Our results found that N application (N2 and N3) significantly increased plant growth and morpho-physiological activities; leaf length increased by 2.7–8.9%, leaf width by 0.4–4.5%, plant height by 27.8–20.5%, Specific leaf weight by 4.2–10.9%, leaf weight by 18.4–17.4%, and protein contents by 39.5–117.0% compared to N1. Interestingly, higher rates of N reduced number of plants m − 2 by 42.4–24.8% but increased number of plants m − 2 weight kg − 1 by 11.6–62.8%. Moreover, compared with control, N enhanced CAT activity by 92.8-131.9%, SOD by 81.2–84.5%, and POD by 43.6–52.8% in 2017 and 2018. This study indicated that N3 significantly performed best among all treatments during the two growing seasons particularly in case of V1. Moreover, we also concluded that V1 performed better in terms of producing higher leaf width, plant height, specific leaf weight, stem weight, number of plants m 2 (weight/kg − 1 ), protein contents, and antioxidant enzymes activity as compared to V2.