Carbon sequestration for better dryland productivity

The world rejoices over the award of the 2007 Nobel Peace Prize to those who focussed on climate change, yet even simple agricultural practices can greatly help mitigate this global challenge. Climate change occurs when there is a build-up of carbon in the atmosphere. However, if carbon is collected (or sequestered) in the soil and used to increase productivity, the results are three-fold — a reduction in atmospheric carbon levels, increased crop yields, and more inc ome for farmers.Ironic as it may sound, in dryland agriculture the availability of organic carbon in the soil is the key to increasing productivity. Hence, "look down at the soil to make your agricultural productivity look up" is the new motto of agricultural scientists, especially those working with natural resource management and watershed development. This, however, calls for massive investment by developed and developing countries to support dryland agricultural research and corresponding support systems.Although there is much attention and support being given to irrigated agriculture, drylands occupy 80 per cent of agricultural land and generate 58 per cent of the world's staple foods. In fact, most of the food for the poor in the developing countries is produced in dryland and rainfed areas. More than 95 per cent of the farm land in sub-Saharan Africa (SSA) is rainfed. In Latin America the figure is almost 90 per cent, in South Asia about 60 per cent, in East Asia 65 per cent and in the Near East and North Africa 75 per cent. In India, 66 per cent of the 142 million hectares of arable land is rainfed.Rainfed areas are also hotspots of poverty, malnutrition, and child mortality. Of the one billion poor people in the world, India accounts for 25.9 per cent and China 16.7 per cent. The rest of the Asia-Pacific accounts for 18.3 per cent. Asia is a hub where the poor, undernourished, and the vulnerable live. This is followed by sub-Saharan Africa, which accounts for 23.9 per cent.A close look at the rainfed regions shows a grim picture of water scarcity, fragile environments, drought, and land degradation caused by low rainwater use efficiency, high population pressure, poverty, poor infrastructure, and inappropriate policies. Drought and land degradation are interlinked in a cause-and-effect relationship, which in turn causes poverty. This unholy nexus among drought, poverty, and land degradation must be broken if we have to meet the Millennium Development Goal of halving the number of food-insecure poor by 2015.Added to this is the threat of climate change. It is anticipated that climate change will lead to more rainfall variability and increased frequency of extreme events, resulting in more and longer dry spells due to global warming.
Soil is the key
Innovative strategies are required to help the dryland farmer overcome these difficulties. As the world's top research centre for dryland agriculture, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in Andhra Pradesh is working on increasing the organic carbon level in the soil through increased sequestration (accumulation from the environment).Soil organic carbon is the source of energy to fuel biological activities in the soil, which in turn control the availability of nutrients for plant growth as well as soil water availability — a critical yield component in tropical drylands.Long-term watershed management experiments at the ICRISAT campus at Patancheru over the last 33 years have consistently demonstrated that drylands can produce 5.1 tonnes of grain per hectare a year, supporting 21 persons as compared to 1.1 tonnes of grain per hectare a year supporting 4.8 persons in case of farmers' practice. Moreover, the system is still gaining at the rate of 78 kg of grain per hectare a year, and the new equilibrium is yet to be reached.Along with increased productivity, improved watershed management practices sequestered 330 kg of carbon per hectare a year up to a depth of 120 cm by intercropping sorghum and pigeon pea. Increased carbon sequestration not only increased nutrient supply and turnover capacity of the soil but resulted in substantial changes in the physical and biological properties of the soil, which increase water holding capacity and the ability to cope with longer dry spells during crop growth.Moreover, ICRISAT's research has shown that legumes in general and pigeon pea in particular have the ability to sequester more carbon in tropical soils. Through the adoption of improved water, soil and crop management options, carbon sequestration in legume-based systems can be improved further. If this is adopted within an integrated community watershed, the productivity of rainfed agriculture can be doubled, providing increased incomes to farmers.
Thirst and hunger
Tropical soils are not only thirsty but also hungry, particularly for micronutrients such as zinc, boron, and secondary nutrients such as sulphur, along with macronutrients such as nitrogen and phosphorus. ICRISAT's work has shown that by adopting integrated nutrient management after testing the soil for deficiencies and combining it with improved crop varieties and water management, rainwater use efficiency can be increased by up to 65-70 per cent along with increased productivity and improved livelihoods.ICRISAT has strengthened its research in partnership with the Indian Council of Agricultural Research under the National Agriculture Technology Project (NATP) funded by the World Bank. A study of 58 samples from 28 benchmark spots in the drylands of India revealed that black soils as well as red soils have the potential to sequester carbon by adopting suitable cropping with high-yielding varieties and legumes, along with management practices such as water management and the use of green manure. ICRISAT works with a consortium of partners including national agricultural research systems, State agricultural universities, civil society organisations and farmers' organisations. Along with accumulating carbon in the soil, our work has led to convergence, collective action and capacity building to empower dryland communities.ICRISAT's watershed development model has been widely accepted in India, China, Thailand, and Vietnam in Asia. It is also moving to Eastern Africa through South-South cooperation.
The hindu October 24
Bio-diesel plant using variety of materials as feedstock developed
A team of Pune-based entrepreneurs has developed a continuous processing bio-diesel plant against the batch-type plants presently in use. A pilot plant with a 1,200 litres per day capacity has been installed at Bhosari, and a US patent for the process has been filed for, Prof Kshitij Patukale, one of the team members says. This advantage of this new technology is that a variety of materials including acid oil, a waste product of the solvent extraction process, can be used as feedstock, says Mr Patukale.
Feedstock
"The bio-diesel industry is worried about availability of feed stock. Efforts in last several years have been concentrated on plantation of bio-diesel species such as jatropha, pongamia, simarruba, neem, etc. The Union and State Government agencies have actively promoted jatropha on thousands of hectares of land all over India. But what are the results? That jatropha is not a 'plant it, forget it' species as was believed. So one cannot depend solely on the non-edible oils as feedstock in India," he says, adding that other sources as feed stock for manufacturing of bio-diesel must be found. According to Mr Patukale, any available oil in large quality with any FFA and different chemical properties should get converted into bio-diesel."A large number of oils such as acid oil, palm oil, rice bran oil, rapeseed oil, soyabean oil, fish oil are available all over the world. Several eminent scientists are talking about castor as 90-day bio-diesel crop," he says asserting that the bio-diesel industry in India today is looking for the right technology to convert any oil into bio-diesel.
One of the major sources of bio-diesel, he points out is acid oil, 10 lakh tonnes per day of which is generated every day in the country as a result of refining of edible oils. Traditionally this is sold to the soap industry, but could be diverted for production of bio-diesel and can yield 98 per cent bio-diesel litre-on-litre. This product, if it meets the norms of the American Society for Materials and Testing, can replace diesel, and cost 10 per cent lower, Mr Patukale says. The pilot plant is presently installed at Jaypex Biofuel Processing Technologies Pvt Ltd, at Bhosari near Pune.

Business Line October 27