Study on effect of organic mulching on soil properties, survival and progressive growth of Aquilaria malaccensis Lamk. (Agar) seedling

Abstract

An experiment was conducted in Sibsagar district of upper Assam, India with different mulching materials and its effect on soil properties, survival, progressive growth and development of Aquilaria malaccensis Lamk. (Agar) seedlings. Treatments were (a) Mulching with green grass and leaves (GGL), (b) Mulching with dry grass (DG), (c) Mulching with rice straw (RS), (d) Mulching with dry leaves (DL), (e) Without mulching (WM) as control. Results showed that soil pH changed significantly, it was 4.4 to 4.6 in 0-20 cm and 4.6 to 4.9 in 20-40 cm soil depth. It decreased in GGL, DG and RS mulching, remained unchanged in 0-20 cm and increased in 20-40 cm soil depth under DL mulching. Organic carbon (%) increased from 1.31 to 1.99 in GGL, 1.33 to 2.05 in DG, 1.01 to 1.96 in RS and 1.02 to 1.32 in DL mulching at 0-20 cm. Mulching effect was statistically insignificant on available nitrogen but available phosphorous and potassium decreased significantly. Soil moisture content follows the trend, RS˃ DG ˃ GGL ˃ DL ˃ WM. Seedlings survived to 95 percent under treatment with RS followed by GGL (91%), DL (90%) and DG (88.33%). Height growth rate become much higher under RS mulching and was recorded 184.9 cm after 1 year followed by DG (146.70 cm), DL (129.60 cm) and then GGL (128.20 cm). Basal diameter was recorded maximum under RS mulching, it was 4.24 cm in one year old seedling followed by DG (3.77 cm), GGL (3.34 cm) and then DL (3.27cm). RS mulching treatment gave maximum number of primary branches (22) followed by DG (19), GGL (15) and DL (12).