Optimizing growth, productivity and nutrient acquisition of maize under semi-arid region: impact of legume integration and nitrogen levels

The current study aimed to identify suitable legumes for co-culturing with maize and optimize nitrogen dose for sustainable maize production in the semi-arid region. The experiment was conducted in a split-plot design by assigning four maize-legumes integrations, viz., sole maize, maize + cowpea (knockdown at 65 days after sowing, DAS), maize + black gram, and maize + Sesbania (knockdown at 25 DAS) in main plots and three nitrogen levels viz., recommended dose of nitrogen (150 kg N ha-1; RDN), 125% of RDN, and 75% of RDN in subplots with three replications. The results showed that integrating Sesbania with maize recorded the maximum improvements in plant height, leaf area index, and dry matter accumulation of maize followed by maize + cowpea. Likewise, the application of 125% RDN led to an improvement in plant height and dry matter accumulation over RDN. However, both remained statistically at par with each other. Legume integration significantly increased maize yield attributing parameters like cob length, girth, and grains per cob. Concerning maize productivity, among the integration, maize + Sesbania registered the highest grain yield (5.63 Mg ha-1), stover yield (9.83 Mg ha-1), biological yield (15.46 Mg ha-1), and harvest index. However, among the nitrogen levels, the application of 125% RDN recorded the highest yields but remains statistically at par with RDN. The maize + Sesbania combination had the highest nitrogen (N), phosphorus (P), and potassium (K) content and acquisition by maize grain. Among the N levels, application of 125% RDN resulted in higher N, P, and K acquisition by both grain and stover compared to other nitrogen levels. The interaction between N levels and maize-legume integration revealed that cultivation of maize+Sesbania with 125% RDN, registered the maximum grain yield (5.91 Mg ha-1) of maize but it remained statistically at par with maize + Sesbania cultivated with RDN. Overall, findings suggested that legume integration, especially Sesbania, and optimized nitrogen management (RDN) is an effective approach for sustainable maize production in the semiarid region.