BISA farms became functional in the very first year of their acquisition, and research work was initiated with limited staff. Simultaneously the development of the farms was continued. The major accomplishments of BISA during the last three years are as follows:
A major challenge for farmers in the Indian sub-continent is to integrate a legume into the cereal-cereal cropping system that can “close the window” of the dry season with the soil covered with crop residues in order to maintain aggregate stability, modulate soil temperature to favor plant/root growth, sequester carbon and mop up the residual NO3-N from the surface soil layers before it is leached into aquifers (ground water). Experiments for sustainable intensification (SI) were conducted by adopting two strategies, namely,
(i) increasing crop yields, and
(ii) increasing cropping intensity through relay seeding or reducing the acreages of Kharif/Rabi fallows. Thus, trials on sustainability of R-W system were initiated by seeding green gram (mung bean) through (i) adjustments in planting dates and cultivar choices (rice/wheat) to facilitate early seeding of green gram, and
(ii) relay seeding of green gram into standing wheat crop by using a high clearance, narrow wheel tractor. Relay seeding can help tackle the terminal heat problem in wheat which resulted in 10-26% yield losses in Punjab in 2010.
In Bihar, the inclusion of green gram (in Rajendra Bhagwati – early wheat) significantly enhanced the total productivity of the system to 16 t/ha equivalent yield of R-W system. Also, the maize-mustard-green gram (mung bean) cropping system performed better than all other major cropping systems (total 8) followed in Bihar. At BISA, Manegaon (Jabalpur), efforts were made to increase the cropping intensity by reducing the acreage of Kharif fallows in Vertisols. We have observed that heavy rainfall events make it difficult for the seed to germinate at low oxygen contents, and most crops fail to germinate in water saturated black soils. Also farmers are often reluctant to practice pre-monsoon direct dry seeding for fear of seed losses and its viability during peak summer season (April – June). We have observed that pre-monsoon dry seeding under the residue mulches is better than waiting for the rains to actually start and then get caught with continuous rains and a messy situation by trying to seed in wet conditions. Direct dry seeding and mulching on CA platforms can circumvent current land fallowing practice in the Deccan and Central plateaus.
Numerous earlier field studies have shown that puddled transplanted rice system adversely affected the productivity of wheat. With ‘double zero-till’ residue retention practices (ZTDSR-ZTW+ R), the total productivity of R-W system gradually improves with each season and net benefits could be as high as about US$ 2K/ha in R-W system.
In order to promote conservation agriculture (CA) on its farms, BISA centres have addressed the critical issues of implements suitable for conservation agriculture, and contributed to the technical knowhow for sustainable intensification and reduction of the acreage of ‘Kharif Fallows’ in the Vertisol belt of Central Plateau region. BISA has also been innovating on water-wise technologies, and addressing issues related with climate change and greenhouse gas emissions. In the last three years (2012-2014), BISA has been laying out multi-location trials to devise a strategy of buffering year to year fluctuations in wheat production. These studies have not only led to the identification of appropriate wheat genotypes with potential to out-yield the best national checks but also pointed out the need to breed new wheat genotypes that are weakly vernalised and can be planted early to make the best use of the residual moisture of the previous rice crop, and that have longer vegetative growth phase as well as early maturity to escape terminal heat. CSW 18 and HD 2967 were adjudged as the most appropriate genotypes. Results of the genomic studies indicated that not only are there genotype x tillage interactions but also cropping system x tillage interactions. Hence it has been suggested that segregation method should be subjected to pressure under conservation agriculture.
Increasing Water Use Efficiency
In a water management trial, the conventional practice (flooded puddled transplanted rice) was compared with drip irrigation system. It was observed that rice can be grown with subsurface drippers and can save almost 57 % of irrigation water without any serious implications on crop productivity. Rice crop raised as a DSR crop and subsequently managed like a flood irrigated crop can still save 20 cm of precious irrigation water. In the presence of surface residues, raised bed-furrow system was as effective as drip system in improving corn productivity and water use efficiency. It was observed that the presence of crop residues as surface mulch generally enabled additional water saving. In Pusa, Bihar, it was observed that a small amount of rice residues retained on the soil surface significantly improved the early growth and vigour and possibly the fertiliser response in winter maize. Additional studies will be needed for integrating the nutrient-residue interactions in conservation agriculture.
BISA centres are today the flag bearers for conservation agriculture. BISA has already generated research products and technical know-how that are being exchanged freely with researchers, extension agents and farmers. Thus, BISA has been ‘seeding innovations and nourishing hopes’ for a better tomorrow.