Effect of Sesbania sesban L. as a Green Manure on Yield of Rainfed-lowland Rice

Abstract

Rice (Oryza sativa L.) is the most important grain crop for more than half of the world's population especially in Asia. Nitrogen (N) plays a crucial role in rice production. The incorporation of the cover crop as a pre- rice crop is the potential to improve the nitrogen used by rice crops. The experiment was conducted on the clay loam of Svay Rieng Province Cambodia in 2022 during the rice cropping season. The trial was designed using Spit-Plot design, with 4 levels of nitrogen (N) as main-plot and Cover Crop (CC) as a sub-plot. The CC was either the absence of CC or the use of incorporated Sesbania sesban L. (30 kg ha-1 ) as a pre-rice crop. The application rate of nitrogen was 0, 35, 70 and 105 kg ha–1 , respectively. Direct-seeded rice (DSR) was 100 Kg ha-1 . The size of each plot was 16 m2 (4 m×4 m). The experiment was conducted in 3 replicates. An analysis of variance (ANOVA) on Plants Height revealed a significant difference at 1% (P < 0.01) effect of nitrogen level. N35 had the greatest average height (82.95 cm) and N0 was the shortest plant height (77.15 cm). Additionally, a significant difference at 1% (P < 0.01) of planting (CC). CC1 was the tallest plant height (81.75 cm), while CC0 was the shortest plant height (78.49 cm). However, the interaction between N level and CC was not statistically significant (P > 0.05) on Plant height. An analysis of variance (ANOVA) on Grain yield showed a significant difference at 1% (P < 0.01) N70 had the highest average yield (4.92 tons/ha) and N0 had the lowest yield averaging (3.53 tons/ha). Planting (CC) was a significant difference at 1% (P < 0.01). CC1 had the highest average yield (4.60 tons/ha), while CC0 had the lowest average yield (4.13 tons/ha). the interaction between N level and CC was not statistically significant (P > 0.05) The results suggested that among 4 levels of nitrogen, The application of any rates of fertilizers increased the grain yield compared to non-N application. The grain yield was even higher with the incorporation of CC as a pre-rice crop.