Effects of Different Management Methods for Sunn-Hemp Cover Crop on Corn Production in a No-Till System in Cambodia

Highlights Soil type, operational speed, machinery weight, and power size affected corn seeding rate and seeding efficiency Corn growth and yield was affected by seeder type, so utilization of appropriate machinery is very important Having cover crop residue on the land can maintain soil moisture for a longer time than tilled land Abstract.Conservation agriculture (CA) is gaining popularity in Cambodia to sustain soil fertility, productivity, and profits. However, the adoption remains slow due to the low engagement so far of local services into CA machinery and technology. Therefore, this paper aimed to compare different no-till seeders and residue retention methods for corn (Zea mays L.) sowing and to determine their effects on growth and yield. The experiment was conducted in Rattanak Mondul District, Battambang Province, in the wet season of 2019. Sunn hemp (Crotalaria juncea L.) was grown as a cover crop for 74 days prior to corn. Each main plot was 14 × 34 m and was subdivided lengthwise with 4.0-m buffers for operations of two different seeders, namely one-row Morrison seeder mounted on 14 kW Oggun tractor and four-row Brazilian seeder mounted on 56 kW John Deere tractor. The results show that using Brazilian seeder saved around 50% of seed and 80% of time, when compared with Morrison seeder. Plant population, plant diameter, and kernel characteristics were also significantly greater with Brazilian seeder, when compared to the Morrison seeder. A combination of the Brazilian seeder and Cambodia made crimper plots had larger ear size and weight. Volumetric Moisture Content (VMC) was significantly affected by residue retention with higher VMC for rolled and crimped residue compared to disked/incorporated residue. The study demonstrates that using no-till equipment such as roller crimpers and no-till planters is feasible in Cambodia’s small farming systems although more research is needed to study long-term effects on crop yields and soil health. Keywords: Battambang Province, Conservation agriculture, Green manure, Soil improvements