Madembo Connie

Title : Demystifying the intermediating role of conservation agriculture on resource pool diversity and weed-crop competition in maize-based farm ecosystems

Abstract:

Weeds are regarded as problematic and costly to control in all global farming ecosystems and are known to compete with crops for essential growth resources (light, moisture, and nutrients). Smallholder farmers, often constrained by limited resources and environmental degradation, hence require novel and innovative approaches to improve productivity while preserving natural resources. Conservation agriculture (CA) offers a promising paradigm for sustainable agricultural development by promoting minimal soil disturbance, permanent soil cover, and crop diversification. The adoption of CA principles facilitates the development of diverse soil resource pools that arbitrates the weed-crop competition for growth resources. For instance, CA preserves soil structure, organic matter content, and moisture conservation thereby fostering a heterogeneous environment conducive to microbial diversity crucial for sustaining soil health and fertility. A three-year study was carried out in Zimbabwe's two on-station experimental sites. We hypothesized that the CA system arbitrates resource pool diversity and weed-crop competition in farm ecosystems thereby increasing soil resource availability and improving maize crop yields, ii) managing weeding frequency and time/period of first weeding improves soil organic carbon and maize grain yields and iii) tillage system, and weeding frequency have dissimilarities/similarities on community weed species composition patterns in farm ecosystems. The main treatments were CA and conventional practice (CP) tillage systems with weeding frequencies (no weeding, weeding at 3, 6, 9, 3 and 6, 6 and 9, and 3, 6 and 9 weeks after planting) and replicated five times in a randomised complete block design. Linear mixed models were used to assess the effects of treatments on the variability of maize grain yield and soil organic carbon (SOC). Overall, CA achieved higher grain yields compared to CP, twice weeding resulted in higher grain yield compared to other frequencies, and periods of first weeding recorded no significant differences while no weeding had the lowest yields at both sites. Additionally, no weeding recorded the highest SOC stock (18789 kg ha¹ and 36331 kg ha¹) at DTC and UZ respectively and the least was observed from weeding frequency two (5703 kg ha¹) at DTC and weeding frequency three (9672 kg ha¹) at UZ sites. The results suggest that the integration of CA practices not only improves soil health and productivity but also enhances the resilience of smallholder farming systems to environmental stresses and climate variability. Thus, the adoption of CA practices holds significant promise for promoting agricultural sustainability in farming ecosystems. Through enhancing soil resource pool diversity and managing weeding frequency, CA fosters resilient and productive agricultural ecosystems, offering a pathway towards food and nutritional security and environmental stewardship in a changing world.

Keywords: compete, essential resources, food security, grain yield, soil health, weeds

Biography:

Miss Connie Madembo is currently a PhD candidate at the Chinhoyi University of Technology, graduated with an MSc in 2018 and a BSc in 2014, Zimbabwe. She holds a position as a Research technician at the International Maize and Wheat Improvement Centre (CIMMYT) in Zimbabwe. She is still developing in her career and has managed to contribute to three publications.