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Key soil parameters, organic matter, soil pH and plant nutrients determine the capacity of a soil to sustain plant and animal productivity. Conservation agriculture (CA) and crop diversification or intensification may change these soil parameters positively or negatively, which eventually affect long-term sustainability. We monitored these key soil properties (at depths of 0–15 and 15–30 cm) under CA-based sustainable intensification practices: zero-till (ZT), and crop residue retention, and crop rotations on Inceptisols and Entisols in the Eastern Ganga Alluvial Plains from 2014 to 2017. The rainfall of this sub-tropical region is 1273–3201 mm. Soil organic carbon (C) ranged within 0.46–1.13% and generally followed (positive) rainfall gradients. At all sites, the soil under ZT tended to have higher organic C than conventional tillage (CT). Soil pHH2O ranged within 5.7–7.8 across the region. At all sites, soil pH generally decreased under ZT compared to CT. This was most marked at some acidic soil sites where pH decreased by up to 0.4 units; the lower the initial soil pH, the higher was the decrease in pH under ZT practice. In contrast, the reverse trend was observed for soil organic C. Partial nutrient balances for N, P and K in rice–wheat and rice–maize systems were positive for N and P (<50 kg ha–1) but negative for K (up to 90 kg ha–1) under both tillage practices; more so under ZT practice even though crop residues were retained. Changes under ZT provide an opportunity to maintain soil organic C. However, remediation measures such as liming and efficient use of fertilisers are required for long-term sustainability of the farming systems in this agriculturally important region of South Asia.

Pearlmillet [Pennisetum glaucum (L.)] is a drought tolerant, warm season cereal crop, largely grown for grain and fodder purpose and ranking sixth in the world following rice, wheat, corn, barley and sorghum. Pearlmillet can be grown in areas which are very hot, dry and soils having very poor organic matter, low water holding capacity and high infiltration rate. It can also grow in areas receiving less than 400 mm annual precipitation, which limit the growth of other cereal crop, due to its well-developed deep root system, short life cycle and fast growing habit. India is the major pearlmillet producing country in the world with Rajasthan sharing the major production (46%) followed by Maharashtra (19%), Gujarat (11%), Uttar Pradesh (8%) and Haryana (6%) (Sonawane et al., 2010). Pearlmillet grain contains about 13-14 per cent protein, 5-6 per cent fat, 74 per cent carbohydrate, 1-2 per cent minerals and higher amount of carotene, riboflavin (Vitamin B 2 )

A field experiment was conducted to determine the persistence of metamifop in transplanted rice crop for two seasons. Metamifop 10% EC was applied at two doses: 100 g a.i. ha and 200 g a.i. ha at 2-3 leaf stage of Echinochloa crusgalli. The residues of metamifop along with its major metabolite, N-(2-fluorophenyl)-2-hydroxy-N-methylpropionamide (HFMPA), were estimated in rice plant, field water and soil using Liquid Chromatography Mass Spectrometry. Limit of detection and limit of quantification of the method for both the compounds were set at 0.003 μg g and 0.010 μg g respectively. Metamifop showed less persistence in field water and rice plant as compared to soil samples. Presence of HFMPA was recorded in rice plant and soil. Both the compounds were found below level of quantification in harvest samples of straw, grains, husk and soil. A safe waiting period of 52 d was suggested for harvesting of rice when metamifop was applied at 100 g a.i. ha (recommended dose).