G.I. Ramkrushna

Crop diversification, crop and energy productivity under raised and sunken beds: results from a seven-year study in a high rainfall organic production system

Low productivity, crop diversification, employment and income are the major constraints of existing production systems of the high-rainfall north-eastern hill region (NEHR) of India. Field experiments were conducted for seven consecutive years to evaluate crop performance, production and energy balance of cropping sequences under raised and sunken bed (RSB) systems in mid-hills (950 m above mean sea level) of subtropical Meghalaya, India. Five vegetable-based cropping sequences on raised beds and six rice-based sequences on sunken beds were tested and compared with rice monocropping (control) under an organic production system. On raised beds, tomato–okra–French bean gave highest rice equivalent yield (REY; 44.7 t ha− 1) followed by carrot–okra–French bean (42.5 t ha− 1). Rice (cv. Shahsarang 1)-pea (cv. Prakash) gave highest REY (17.3 t ha− 1) on sunken beds. Among raised bed sequences, tomato–okra–French bean recorded greatest production efficiency (162 kg ha− 1 day− 1) and carrot–okra–French bean recorded highest land use efficiency (77%). Employment was enhanced by 187% with potato–okra–French bean and 181% with tomato–okra–French bean on raised beds, whereas rice–pea sequence on sunken beds enhanced employment by 62% over monocropping of rice. The energy productivity (energy output/input) was also higher with these cropping sequences. The adoption of RSB land configuration facilitated 244% cropping intensity (gross cultivated area/net cultivated area × 100) compared with 100% in rice monocropping. There was a significant improvement in soil chemical and biological parameters due to continuous organic production under RSB land configuration, indicating potential for organic farming in the subtropical hill ecosystem of India.

IMPROVING PRODUCTIVITY, WATER AND ENERGY USE EFFICIENCY IN LOWLAND RICE ( ORYZA SATIVA ) THROUGH APPROPRIATE ESTABLISHMENT METHODS AND NUTRIENT MANAGEMENT PRACTICES IN THE MID-ALTITUDE OF NORTH-EAST INDIA

Rice is the major staple food crop in the North Eastern Region of India (26.2 million hectare geographical area) and the region has a deficit of 1.40 million tones of rice, mainly due to low productivity (1.72 t ha −1 ). Field experiments were conducted for the first time to evaluate the new techniques of rice cultivation, viz. the system of rice intensification (SRI) and integrated crop management (ICM) along with conventional rice culture (CRC) for improving productivity, water and energy use efficiency during the rainy seasons of 2004–07 at the ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya (950 m msl), India. Three stand establishment methods, viz. SRI, ICM and CRC in main plots, and five nutrient management practices, viz. recommended dose of fertilizers (RDF = 80:26:33 kg NPK ha −1 ), farmyard manure (FYM) 10 t ha −1 , RDF + FYM 5 t ha −1 , 50% RDF + FYM 10 t ha −1 , and a control (no fertilizer and manure) in sub-plots, were tested in a split-plot design; only few meaningful interactions were found. Results showed a higher number of panicles per square metre under CRC and ICM compared with SRI. However, the number of panicles per hill, grains per panicle and the test weight remained higher in the SRI method. In terms of mean grain yield, ICM (4.86 t ha −1 ) and SRI (4.72 t ha) produced 12.8 and 9.6%, respectively, higher grain yield over CRC (4.3 t ha −1 ). Among the nutrient management practices, the application of RDF + FYM 5 t ha −1 (5.0 t ha −1 ) and 50% RDF + FYM 10 t ha −1 (4.87 t ha −1 ) not only produced higher grain yield of rice (23.8 and 20.5%, respectively, higher yield over control) but also maintained higher soil available N, P and organic carbon at harvest compared with other nutrient management practices. Photosynthesis rate and water use efficiency were found to be significantly ( p

CONTINUOUS APPLICATION OF ORGANIC AMENDMENTS ENHANCES SOIL HEALTH, PRODUCE QUALITY AND SYSTEM PRODUCTIVITY OF VEGETABLE-BASED CROPPING SYSTEMS IN SUBTROPICAL EASTERN HIMALAYAS

SUMMARY The hill ecosystem of Northeastern Himalayas is suitable for organic farming due to negligible use of fertilizer (<12 kg ha −1 ) and agrochemicals, abundance of organic manure, especially plant biomass, and favourable climatic conditions for diverse crops. For successful organic farming, efficient cropping systems and organic amendments are to be identified to sustain soil health on one hand and productivity and enhanced income on the other. The efficacy of three organic amendments, namely, farmyard manure (FYM), vermicompost (VC) and integrated nutrient source (INS; 50% recommended dose of nitrogen (N) through FYM + 50% N through VC) on performance of three-vegetable-based cropping systems, namely, maize + soybean (2:2 intercropping)–tomato, maize + soybean–potato and maize + soybean– French bean was evaluated for five consecutive years (2005–06 to 2009–10) under subtropical climate at Umiam, Meghalaya, India (950 m above sea level). All the organic amendments were applied on N equivalent basis and phosphorus (P) requirement was compensated through rock phosphate. The results revealed that the yield of vegetables, except root vegetables, was maximum with FYM as soil amendment. Total system productivity in terms of maize equivalent yield (MEY) was significantly higher under FYM followed by INS. Pooled analysis revealed that MEY was enhanced by 200 and 191% with continuous application of FYM and INS, respectively, over control (no manure). Maize + soybean–tomato system recorded the highest MEY (28.78 Mg ha −1 ; Mg – megagram) followed by maize + soybean–French bean (24.37 Mg ha−1). INS as organic amendment resulted in maximum improvement in soil organic carbon (SOC), available P and potassium (K), soil microbial biomass carbon and water holding capacity and was similar to those under FYM. The SOC concentration under INS (23.6 g kg−1), FYM (23.3 g kg−1 )a nd VC (22.3 g kg −1 ) after five years of organic farming were 31.0, 29.4 and 23.8% higher than the initial and 26.2, 24.6 and 19.3% higher than those under control, respectively. The quality traits of tomato such as total soluble solids (5%), ascorbic acid (28.6 mg 100 g −1 ) and lycopene content (19.35 mg 100 g −1 ) were higher under FYM application than other amendments. The study indicated that FYM and INS are equally good as organic amendment and their continuous application not only improves soil health but also crop productivity. FYM application was also found to be cost effective as it resulted in a higher benefit: cost ratio (4.4:1) compared to other amendments irrespective of cropping sequences during transition to organic farming.

Weed management in maize under rainfed organic farming system

Field experiment was conducted under organic farming for three consecutive years during 2008–09 to 2010–11 to study the effect of different non-chemical weed management practices on productivity and weed infestation in maize in mid altitude (950 m MSL) of Meghalaya, India. Total eight treatment in three replication were evaluated on maize. Grain weight/cob of maize was maximum under mulching with fresh Eupatorium sp. biomass after earthing up at 30 days after sowing (DAS). The highest maize yield was recorded under mulching with fresh Eupatorium 10 t/ha, but it was statistically at par with two hand weeding (HW) at 20 and 40 DAS, weed free check and soybean green manure incorporation in situ + one HW. Two HW, soybean green manure incorporation + one HW and mechanical weeding (20 DAS) + one HW (after earthing up) were found to be effective in weed reduction in maize. Weed control efficiency was recorded maximum under two HW which was at par with mechanical weeding (20 DAS) + one HW. Available N, P, K and soil organic carbon concentration after 3-croppoing cycles were maximum under mulching with fresh Eupatorium 10 t/ha treatment followed by soybean green manuring + one HW (45 DAS) than those under other weed management practices. Thus, mulching with fresh Eupatorium (after earthing up) and soybean green manuring + one HW were the recommendable options for sustainable organic maize production under high rainfall hill ecosystem of North-East India.