Weed strip management for minimizing soil erosion and enhancing productivity in the sloping lands of north-eastern India

- An erosion control technology with weed strip management designed for steep slopes.
- Selective weed retention led to four times lower soil loss than shifting cultivation.
- The designed technology led to formation of mini-terraces and reduced land slope.
- Plant and root growth of test crop (maize) was also superior in the treatment.

Soil erosion and shifting cultivation are the major constraints to agriculture in the north-eastern region of India. Low acceptance of cost-intensive soil conservation technologies (e.g., terracing) calls for developing low-cost erosion control measures. Thus, a field experiment was conducted during the monsoon period of 2008 and 2009, in runoff plots on a land slope of 40% to test the hypothesis that weed cover, if properly managed, minimizes soil erosion and improves soil productivity. The treatments implemented in duplicates were: maize (Zea mays) under shifting cultivation (T1), maize on contour lines (T2), groundnut (Arachis hypogea) on upper and maize on lower half of treatment plot, with both on contour lines (T3), groundnut on contour lines (T4) and maize on contour lines with natural vegetation as buffer strips (T5). The average sediment concentration of runoff water varied from 5.20 g L−1 (T1) to 1.07 g L−1 (T5) in 2008 and from 3.84 (T1) to 0.89 g L−1 (T5) in 2009. The soil loss ranged from 20.8 (T1) to 4.7 Mg ha−1 (T5), with corresponding loss of 670-147 kg ha−1 of SOC, 6.85-1.48 kg ha−1 of available N, and 2.14-0.87 kg ha−1 of available P. Weed strips and weed mulch on the upstream side of maize rows in T5 led to formation of stable mini-terraces promoting better plant and root growth. This study indicates cover management involving selective weed retention can reduce soil erosion, favourably modify land slope and promotes soil productivity.