INFLUENCE OF SOIL ORGANIC AMENDMENTS ON MORPHOLOGY AND YIELD OF RICE UNDER DROUGHT STRESS

Abstract

A pot experiment was conducted to investigate the influence of soil organic amendments-cowdang and humic acid on morphology and yield of rice under drought stress at the net-house,Department of Agricultural Botany, Sher-e-Bangla Agricultural University, Dhaka during the period from July 2018 to November 2018. In this two factorial experiment pots where arranged in a randomized complete block design with four replications. The factors are (A) Four different levels of water deficiencies viz. D 1 = Well watered condition (Control), D ii 2 = Irrigation at 7 days interval, D = Irrigation at 14 days interval and D = Irrigation at 21 days interval and (B) Four different levels of soil organic amendments viz. SM 4 = Soil + inorganic fertilizer (control), SM 2 = Soil + cowdung + inorganic fertilizer, SM 1 = Soil + inorganic fertilizer + humic acid and SM 4 3 = Soil + inorganic fertilizer + cowdung + humic acid. The morphological characters such as plant height, tiller number plants at different days after transplanting and yield contributing characters such as days required to flowering, panicle length, number of grains per panicles, grain weight and yield of rice varied significantly followed by different levels of water deficiency. The results showed that more than 36% yield was reduced under drought condition where the plants were irrigated with 21 days interval. In this experiment, cow dung and humic acid were used to find the interaction of soil organic amendments for changing the adverse effect of drought on rice cultivation. The results showed that morphological characters and yield of rice significantly increased with addition of cowdung and humic acid into the soil. This experimental results highlighted that together use of cowdung and humic acid increased the grain weight plants -1 more than 150% compared to controlled condition. The interaction effect of drought and soil organic matter also significantly changed the morphological characters and yield of rice. It is noted that rice plant failed to survive 70 DAT from the treatments of D D 4 SM 1, D 4 SM . In terms of combined effect of different levels of water deficiency and humic acid the highest panicle length (26.25 cm), number of grains panicle 2.

(255.80), grain weight hill -1 (29.30 g) and straw weight hill -1 (35.38 g) were recorded from D 1 H whereas the lowest performance was observed from the treatment combination of D 4 4 H . Finally, it concluded that application of cowdung and humic acid as soil organic amendments increases the yield of rice by increasing the plant hight, tiller number, penicle length, grain weight undetr water deficit condition and/or drought stress.