Tillage and mulching influence weed community dynamics and crop productivity of Sesbania alley-based food-fodder systems in rainfed agro-ecosystems

Context or problem: Crop yield in rain -fed agro-ecosystems is limited by low soil moisture availability and weeds. Objective or research question: This study aimed to answer the questions- 1. Do tillage practices, mulching and Sesbania alley -based food -fodder cropping system affect weed dynamics under rainfed agro-ecosystem? and 2. Is the productivity of a Sesbania alley -based rainfed food -fodder system affected by tillage practice, mulching or crop sequence? Methods: A four-year field experiment was conducted with Sesbania alley -based food -fodder systems (sorghum - chickpea; sorghum - barley; sorghum - mustard), and three tillage practices (conventional tillage; minimum tillage during rainy season - zero tillage during winter season; conventional tillage during rainy season - zero tillage during winter season) with and without mulch. Results: During the study period, conservation agricultural techniques resulted in a shift in weed flora in all Sesbania alley -based cropping systems. Grass, broadleaf, and total weed densities declined by 8-9%, 35-38%, and 11-13%, respectively, across diverse cropping systems from 2014 to 15; however, sedge population increased (13-29% increase) during the same period. Mulching practices considerably reduced sedge density compared to the without -mulch treatment in all the tillage combinations. The lowest total weed biomass was recorded for minimum tillage during the rainy season and zero tillage + mulching treatment (17 g m-2) during the winter season. Weed species abundance and dominance were greater in 2014, while the diversity and evenness of weed species were higher in 2016, which indicates a weed shift. Sesbania hedgerow + (sorghummustard) with conventional tillage during the rainy season and zero tillage during the winter season without mulching had the highest weed diversity index and evenness than that of other treatment combinations. The Sesbania dry matter (DM) yield was significantly higher by 13% and 11% in minimum tillage during the rainy season and zero tillage during the winter season with mulching compared to conventional tillage without mulch in 2015-16 and 2016-17, respectively. However, tillage and mulching had a significant effect on the grain and straw yields of winter crops. All the tillage practices with Sesbania mulching recorded higher grain and straw yields for winter crops compared to the un-mulched treatments. Conclusions: The innovative Sesbania alley -based rainfed food -fodder system, along with reduced tillage and mulching, improved productivity and altered weed dynamics. Implications or significance: The knowledge gathered on weed dynamics may aid in determining weed management tactics under conservation agricultural practices. Double cropping is possible without compromising fodder needs by employing suitable tillage and mulching procedures, as well as Sesbania alley -based cropping systems.