Smart water saving techniques for mitigation of climate change impacts in hill agriculture

GT Patle *

Climate change expected to intensify the demands of water use in agriculture as climate is the major driving force for crop production and water use. Studies on climate change have indicated the variation in temperature and precipitation patterns globally due to increased concentration of greenhouse gases. Global warming and its consequences have shown remarkable impacts on regional hydrologic cycle.

Temperature and precipitation are two important climate parameters and plays a vital role in crop production system. The rise in air temperature and varying precipitation pattern may affect the crop yield and water use efficiency. Rise in temperature is likely to increase the evapotranspiration demand and water requirement for agriculture.

In India, agricultural sector is the major consumer of water especially irrigated agriculture which accounts about 90% of water consumption. Hill agriculture is more susceptible to climate change due to its topographical features. Climate smart water saving technologies can playimportant role in the climate change mitigation and adaptation and in the sustainability of hill agriculture.

Agriculture in the north-eastern region

Agriculture is the mainstay of livelihood in the north eastern states of India. The state of art of cultivation of crops is somewhat different in the region compared to the plain region of India. The NE region produces only 1.5% of the country’s total food grain production and provides livelihood support to 70% of the population.

Peoples follow agriculture for their livelihood which is integrated with the cattle rearing. North-eastern region comprises the eight states namely Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura and is located between 21.50 to 29.50 North latitude and 85.50 to 97.50 East longitudes. The total geographical area is of 262185 sq. km which is 7.9% of the country’s total area.

Out of this about 55% is under forest cover, about 14.5% and about 2.2 million ha is estimated to be not available for cultivation. Whole region falls under the high rainfall zone and the climate ranges from subtropical to alpine. The region is characterized by difficult terrain, wide variations in slopes and altitudes, land tenure systems and indigenous cultivation practices.

Variation in altitudes blessed the region for growing different cereals, oilseeds, pulses and horticultural crops and several medicinal plants.

Major challenges for hill agriculture

The major challenges for hill agriculture in view of climate change are to produce
(i) more food,
(ii) more efficiently,
(iii) under more unstable production conditions and
(iv) with net reductions in GHG emissions from food production and marketing.

This can be tackled at certain extent by giving emphasis on water management through water saving, increasing the water use efficiency and soil moisture conservation.

Projected impacts of climate change on crop production in 2030s. According to the report Indian Network on Climate Change Assessment (INCCA) the yield of major crops namely rice, wheat and maize which are grown extensively in the region are likely to reduce in future. The irrigated rice yield may vary about 10% to 5% and rain fed rice yield is likely to be in the range of 35% to 5%.

The crop yield of maize and wheat are projected to reduce by 40% and 20% in the entire north east region respectively. Productivity of maize and mustard is also expected to decrease in 2030s. Potato yields are likely to increase up to 5% in upper parts of north east region and likely to decrease by about 4% in the central part of the north east region. This may be considered as major threat for hill agriculture for its sustainability in context of climate change.

Climate change and hill agriculture : Land and water are the two basic resources of crop production system.

Variations in the climatic parameters viz., temperature, wind speed, humidity and sunshine hours governs the crop water requirement and also decides the future water requirement of agricultural crops. The projected changes in climate such as increase in temperature, increase/decrease in rainfall, decrease in rainy days and increase in rainfall intensity are likely to influence the hill agriculture of north east region.

The region is prone to floods and soil erosion and also experiences the drought of heavy rainfall. It is further expected that the climate change will accelerate the soil erosion and will cause the nutrients and fertility loss due to increase in the extreme events such as rainfall amount and intensity which will deteriorate the soil health.

Decrease in rainy days will affect the water availability for the crops and also water storage for irrigation which will adversely affect the crop yield. Water scarcity in future will be major constraints for the food production. Increase in temperature is expected to cause the more evapotranspiration and would increase the crop water requirement in future.

Climate smart water saving techniques

Water is one of the important inputs in the sustainable crop production system. Scarcity of water may affect to the food production and create the problem of food security in a region. Agriculture is the largest user of water and climatic variability and may further impose the water related problems for irrigation and domestic use.

Water saving technologies are based on the improvement of agronomic practices by improved crop varieties, substitution of crops and improved cultivation practices. Secondly, through better water management using the improved water management techniques, like precision irrigation.

It not only prevents over-watering, but saves unnecessary pumping costs and helps prevent leaching of fertilizers.

b) Optimization of conventional irrigation methods:
Conventional irrigation methods like border check basin and furrow irrigation methods are being used by the farmers from very old times. Optimizing the design of conventional irrigation methods water productivity of the different crops can be increased.

c) Use of organic and non-organic mulch:
Mulches can reduce up to 25% water requirements considering the crop, soil and climatic conditions. When drip irrigation is laid underneath the plastic film, it delivers water and fertilizer to the plants and evaporation is reduced. But, because there is no surface evaporation of water, it is easy to over-irrigate crops.

5) Use of modern irrigation techniques

i) Drip or Micro-Irrigation
Drip irrigation delivers water and fertilizer either on the soil surface or directly to the roots of plants through systems of plastic tubing and emitters. By distributing these inputs slowly and regularly, drip irrigation conserves 50 to 70% more water than traditional methods while increasing crop production by 20 to 90%. The water and fertilizer are also more easily absorbed by the soil and plants, reducing the risks of erosion and nutrient depletion. Usually operated by gravity, drip irrigation saves both the time and labour that would otherwise be needed to water crops, leading to larger harvest yields.

ii) Subsurface Irrigation Systems : In subsurface irrigation method water is applied at the certain depth below the soil surface. Advantages of subsurface irrigation systems includes water savings, improved crop yields, no surface evaporation, no soil and nutrient runoff, less disease and fewer weeds, less labor and reduced amount of energy is required for pumping

iii) Deficit Irrigation : In deficit irrigation, major focus is to obtain maximum crop water productivity rather than maximum yield. In this method the little less water is applied to the crops than a crop’s optimal full requirement. Doing this yield may reduce by 10%, but save 50% of the water.

For further details contact:-
Public Relation & Media Management Cell,
CAU, Imphal.
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