Print Edition - 2016-01-19 | Oped
A quiet revolution
- There are challenges to adopting Conservation Agriculture but its potential benefits are considerable
Jan 19, 2016-
Agriculture is the foremost source of livelihood in Nepal, but production is barely sufficient to meet the domestic demand. Low productivity of conventional agriculture in Nepal is due to accelerating soil erosion and nutrient losses, depleting soil organic matter and water resources, mounting cost of production and paucity of agricultural labour. Intensive tillage can also have a negative impact on the environment by accelerating soil carbon loss and greenhouse gas emissions, mainly carbon dioxide, nitrogen oxide and methane. The annual loss of soil from agricultural fields in Nepal ranges from a mere 0.1 tonnes per hectare to as high as 105 tonnes per hectare, causing an estimated nutrient loss of 300kg organic matter, 15kg nitrogen, 20kg phosphorus, and 40kg potassium—assuming a soil loss of 20 metric tonnes per hectare from a marginalised rain-fed agricultural land in the mid-hills. Additionally, a loss of 1mm topsoil causes a loss of 10kg nitrogen, 7kg phosphorus and 15kg of potassium per hectare. A lot of crop residues are being burnt after the introduction of combine harvesters in the Tarai. The Food and Agriculture Organisation of the United Nations estimates that greenhouse gas emissions from agriculture, forestry and fisheries have nearly doubled over the past fifty years and could increase an additional 30 percent by 2050. With the present crisis and ever-increasing prices of fuel, tillage and intercultural operations now account for a higher proportion of production costs (more than 60 percent) than harvesting does.
In recent days, Conservation Agriculture (CA) has been considered as an alternative system to conventional agriculture. CA is characterised by three principles of minimum mechanical soil disturbance, permanent organic soil cover and crop rotations. Since CA significantly reduces human-induced disturbances in soil, there is almost no sound above and below the soil surface while growing crops. Hence, it is considered ‘a quiet revolution’ in agriculture.
There are several benefits of CA. It improves the soil fertility—increasing the soil’s organic matter and reduding soil erosion by up to 90 percent compared to an intensively tilled field. In a five-year
experiment on maize-rice system in Rampur, Nepal, the author found the soil organic matter of 3.19 percent in CA against the 2.72 percent in conventional agriculture. CA conserves soil moisture—increasing crop yield by 10 to 100 percent. It also reduces weed infestation; the author found lowest densities and biomass of weed in a maize field.
CA leads to increased profit. First, it eliminates tillage equipment and its maintenance. Second, it reduces fuel costs, as well as tractor horse power requirements. Third, it reduces labour costs. In some cases, no-till allows farmers to grow more crops in rotation while continuing to maintain excellent erosion control. At Rampur, a maize based system revealed that the benefit-to-cost ratio of CA was 2.01, compared to 1.58 in conventional tillage. Last but not least, in CA, soil erosion and runoffs are dramatically reduced whereas water infiltration, soil organic matter content, and soil biological activity are increased.
Globally, CA has been adopted in around 129 million hectares, of which 45 percent are in South America, 32 percent in North America, 14 percent in Australia and New-Zealand and nine percent in the rest of the world. In Asia, more than 3.1 million hectares are under CA in China, and 23,000 hectares in North Korea. In South-Asia, under wheat-rice cropping system, wheat is grown without tillage in 5 million hectares, but not under full CA. However, there are no reports of full CA adoption among the farmers in Nepal.
There are several challenges to adopting CA practices in Nepal. CA systems are much more complex than conventional ones. To begin with, there are technological challenges, which relate to development, standardisation and adoption of farm machinery for seeding with minimum soil disturbance, and developing crop harvesting and management systems. CA practices such as no-tillage and surface maintained crop residues result in resource improvement steadily, and benefits accrue only with time. Indeed in many situations, benefits in terms of yield increase may not come in the early years after adopting CA. Therefore, CA must take a long-term perspective.
Moreover, in Nepal, crop residues have competing uses; they are used as animal and poultry feed and fuel. Also, introduction of combine harvesters for rice and wheat harvesting in the Tarai without offering alternative residue collection or utilisation practices has accelerated open agricultural burning. Finally, over the centuries, tillage has been considered a good farming practice and is taught as a fundamental agricultural operation in formal agricultural studies and training programmes. Getting over this mindset is also a challenge.
Change never appears overnight and will take time. Any new technology must bring the farmer a visible and immediate benefit, economic or otherwise. The costs incurred must be borne by the farmer. The benefits of CA should be demonstrated in the fields. Farmers Field Schools need to be conducted in Agricultural Resource Centres, where research and extension team up. Extension personnel, technicians and pioneer farmers can enhance the confidence level of other farmers. Once the farmers and field level agricultural technicians are convinced, they should proceed to convince policy makers—with ample data on crop performance, soil and environment and economics—to formulate CA-responsive policies. This could lead to an alternative paradigm for this century in the form of a quiet revolution.
Karki is senior scientist at Nepal Agricultural Research Council
Published: 19-01-2016 08:54