Need for a Climate Smart Agriculture…

Agriculture might look like a profession that helps mitigate Global Warming and Climate Change, but they too contribute to climate change in the form of Green House Gases.

What is a Green House Gas (GHG)?

Gases that trap heat in the atmosphere are called as Green House Gases. The increase of heat trapped in the atmosphere makes earth warm, a phenomenon referred as Global warming.

Modern agricultural systems emit three GHG’s –

1.Carbon-di-Oxide (CO2)

2. Nitrous Oxide (N2O)

3. Methane (CH4).

Their effect is based on following three factors:

1. Abundance of Gas
2. Stay time of these Gases in the atmosphere
3. Warming potential of these Gases

These GHG’s absorb infrared radiation thereby trapping and holding heat in the atmosphere.  Global Warming Potential is measured in terms of the heat trapped by CO2.

Nitrous Oxide traps a whopping 298 times more heat than the same amount of CO2.

Methane traps 35 times more heat than the same amount of CO2.

GHG’s are transferred from the biosphere into atmosphere through natural processes such as respiration by plants and animals and through human activities.

The main human activities that cause the GHG emissions are

1. Use of fossil fuel
2. Industrial processes
3. Deforestation
4. Intensive Livestock farming
5. Use of synthetic fertiliser.

GHG’s in agriculture have their source from

1. Decomposition of bio-mass
2. Soil respiration
3. Combustion of fossil fuels for on farm equipment’s like tractors
4. Burning of wood for energy
5. Burning of crop residues
6. Soil management (Ex: Cultivation)
7. Manure management
8. Live stock
9. Manure
10. Rice paddy.

How to mitigate these GHG emissions?

1. Decreasing emissions in agriculture
2. Sequestration of Carbon in plant biomass and soil organic matter
3. Provide products such as fuel wood and timber than can substitute fossil fuels and energy intensive materials like steel.

Biomass Carbon: Defined as living or dead organic matter. Includes parts above the ground such as leaves, branches, stem and below the ground, roots.

Carbon Sequestration: Refers to the process by which atmospheric carbon is absorbed by biomass in trees, crops and in soils.

Carbon Stock: Refers to the absolute quantity of carbon held within a pool at a specified time.

How is Biomass Carbon measured?

1. Depends on the size of the plants and varies between species, climatic conditions and plant management.
2. Above ground biomass is the most significant carbon pool in farming systems. Diameter at Breast Height (DBH)of 1.3 metres from trunk is general predictor of biomass
3. Below ground bio-mass constitutes generally 26% of Carbon pool.

Soil Carbon: Exists in Organic (decaying plant material, soil organisms and microbes) and Inorganic CO2 trapped in mineral form like Calcium Carbonate.

Soil organic Carbon increases

1. Nutrient availability
2. Soil structure and physical properties
3. Soil bio-diversity.

Hence to conserve Soil carbon, agriculture has to prefer

1. Minimum soil disturbance
2. Maximum soil surface cover with cover crops
3. Species diversification.

Threats to Soil Carbon:

1. Intensive Cultivation
2. Soil erosion
3. Burning or removal of residues
4. Overgrazing.

Green House Gas emission from Livestock

Methane is produced as a part of the normal digestive process in animals. Known as enteric fermentation. Microbes ferment the food and release Methane primarily through animals mouth as burps.

The amount of Methane emission depends upon

1. Animal’s digestive system.

• Amount and type of feed. Lower quality and Higher quantity of feed increases emission.

Ex: Animals fed on Napier grass may produce more methane than those fed on diets with greater quantity of legumes.

Decomposition of manure results in the emission of Methane and Nitrous Oxide. Feeds that are easily digested emit only less gases. Legumes and Cereals are rich in fibres and hence easily digested.

Hence its better to store feeds in solid forms, than liquids which emit more methane.

• Reduce the number of animals by moving the less productive animals out.

• Eliminate parasites and nutrition deficiencies in livestock so that they use the feeds effectively by acquiring maximum feed energy.

Source: Shem Kuyah, Margaret Thiong’o et al., Measuring Greenhouse Gas Emissions, Carbon Stocks and Stock Changes in Small Holder Farming Systems., World AgroForestry Centre, Kenya, 2025.

Half of Methane in India is secreted from cattle population as we have 300 million cows/buffaloes here. India has the largest number of cattle and stands first in total milk collected, but it stands poor in terms of miik yield per animal. Our milk production is just one sixth of world average. One tenth of New Zealand’s cattle yield. While an average US cow offers 9000 litres of milk in a year, Indian cows offer only 1700 a year. This results in a need for more animals leading to much more Methane emission.

Exotic cow species in India yield around 9.9 kgs of milk a day while cross breeds yield 7.2 kgs.

India faces a deficit of 12% green fodder, 24% dry fodder and 29% concentrated fodder for milch animals. Poor food intake results in animals working much for digestion while good food gets easily digested and cow works on milk secretion in a stress free condition.

Digestion burbs release 90% of Methane in cattle while dung manure creates only 7% of Methane.

Temperature Humidity Index (THI) is another important factor which decides the milk production. An ideal THI should be around 72. It was 89 0n March 16, 2025. The fatal level is around 90. Hence our cattle face huge heat stress during summer months. Last year it crossed 100 in Tamil Nadu and 110 in Kerala, resulting in over 4000 cattle’s losing their lives in Kerala alone.

Methane emitted by Oil and Gas companies are tracked by satellites. Soon Methane emitted by cattle would also be sensed in the same manner.