Effect of Slope Length on the Soil and Nutrients Loss from the Upland (Hill) of Bangladesh on Jhum Crops

The experiments were conducted in the hill district of Bangladesh (CHTs) i.e Bandarban, under the AEZ 29 (Northern and Eastern Hills Tract) during March 2016 to November 2017 to study effect of slope length on the soil and nutrients loss from the upland (hill) of Bangladesh. The experiments were laid out in randomized complete block design (RCBD) with three replications. The treatments for the experiment were: T1 30m slope length, T2 20m slope length, T310m slope length and T45m slope length. The highest soil loss of 50.0 t/ha/yr was recorded in treatment L1 having the slope length of 30 m and the plot size 150 m2 (30 m × 5 m). The lowest soil erosion was noted (4.75 t/ha/yr) for L4 treatment with the 5m slope length having area coverage area of 25 m2. The amount of soil loss in L2 (20 m length) and L3 treatments (10 m length) were 42.7 and 21.9 t/ha/yr, respectively. Nutrient depletion increased with the increasing lengths of the hilly land along the slope. The highest depletion of OM and plant nutrients were recorded under the maximum slope length of 30 m (L1) being followed by the losses observed in L2 (20 m), L3 (10 m) and L4 (5 m) plots respectively. The maximum losses of OM, total N, P, K, Ca, Mg and S were 2542, 93.1, 0.295, 2.73, 35.2, 20.6, and 1.34 kg/ha/yr, respectively for L1 (30 m) plot. Slope length created a very positive impact on yield of Jhum rice. The maximum yield of Jhum rice was produced under 30m slope length (2.25 t/ha). Slope length had considerable influence on the performance of Jhum crops like sweet gourd, marpha, maize, white gourd and cowpea.