Climate smart water saving techniques for mitigation of climate change impacts in hill agriculture
- Part 1 -

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. Water saving techniques are also useful for reducing the emission of green house gases responsible for the global warming and climate change.

Water can be conserved in a number of ways by using it more efficiently than most conventional practices.

1. Water saving techniques for rice
Rice is an important cereal crop grown in the northeast region. Different water saving techniques for rice cultivation are in practice in many parts of the region. Achieving higher water use efficiency by using less water to obtain higher rice yield is very important in the context of climate change. Different water saving techniques are briefly explained here.

A) Alternative wetting and drying (AWD)
In this technique the irrigation water is applied to flood the field for a certain number of days after the disappearance of ponded water. Thus, the field is alternately wetted and dried for the certain period. Research studies have reported enormous potential for saving water and increased productivity of rice grown using this method as compared with traditional flooded rice cultivation. In this method water saving up to 15-30% can be achieved compared to conventional methods of rice transplanting.

B) System of rice Intensification (SRI)
In this method the fields are kept un-flooded and the soil well aerated throughout the entire vegetative growth. Only a little water is kept on the field during the reproductive growth phase. This method is becoming popular among the smallholder farmers of hill regions. Using SRI methods of farming, farmers can get higher yields with fewer inputs.

C) Aerobic rice
In these techniques the rice is cultivated like wheat and maize crop as irrigated upland crop. Irrigation is applied to bring the soil water content in the root zone up to field capacity after it has reached a certain lower threshold.

D) Saturated soil culture (SSC)
The soil is kept as close to saturation as possible. Studies have shown that using this technique, water input decreases by 5% to 50% from the continuously flooded check basins with an average of 23%. This method has reported the reduction in yield about 6% on an average but the overall water productivity increases.

To be continued...


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