Case5-June-2017
Soils are the foundation for agriculture, livestock production and forestry. Proper management of soil ensures clean water, capture of carbon dioxide from the atmosphere and provides many other ecosystem services. Seasonal variations in rainfall due to climate change have increased the risk of farming in rainfed regions. Long dry spells in rainfed farming could not provide adequate moisture for crops resulting in crop failure and re-sowing of crops. Increased cost of cultivation and high risk with less adaptive capacity of farmers made them opt for organic agriculture. A pilot project to address climate change and find adaptation measures with the support of GIZ, New Delhi has been implemented in Kilankulam village of T. Kallupatti block from 2011 to 2014.
Soil type of the land is broadly classified into two categories by the local communities as “pottal” (clay with less moisture holding and fertility) and “karisal” (black cotton soil with high moisture holding capacity and good fertility compared to pottal soil). Totally, 55% of the agricultural land soil type is pottal, which is not suitable for cultivation and requires more input cost for crop cultivation. Sensitivity of this non-climatic factor on crop production manifests as wilting of plants due to non-availability of moisture and has led to crop yield loss or total failure.
The effect of adaptation strongly depends on rainfall received during the cropping period. The rainfed farming activity takes place between July and May. The table and graph shows rainfall data of the project area collected from automatic rain gauge installed at Kilankulam and Muthulingapuram villages by People Mutual of DHAN Foundation.
There was consecutive drought in the pilot project implemented period. The average annual rainfall of T. Kallupatti block is 806 mm. Analysis of long-term rainfall data (1901-2004) shows that the district receives rainfall during NE monsoon (47%), SW monsoon (32%), summer (17%) and winter (4%). Out of the total rainfall, July to September rainfall decides the farming pattern. Generally, during this period, 258 mm rainfall is received and it is highly sufficient to carry out all agricultural activities. However, in the study period, the pilot project area received 128 mm (15.9%) and 94.5 mm (11.72%) in 2012 and 2013, respectively against the normal annual rainfall.
Variation in the south west monsoon was 18.20% for 2013. It clearly shows that the climate changed in the rainfall aspect. Overall, the gap in the rainfall for 2012 was 396 mm (49.13%) and 313.40 mm (38.88%) for 2013. With this deficit rainfall, the farmers carried out rainfed agriculture. It was a very good opportunity to observe the result of adaptation activities in the field.
Electrical conductivity (EC) is one of the important factors to determine crop growth and yield. The field was continuously irrigated by using ground water having salinity. Excess use of inorganic fertiliser leads to increase in EC value of soil. Application of tank silt has resulted in reduction of EC in all the agricultural fields. The reduction of EC ranged from 0.02 to 1.21.
Tank silt has significant amount of organic carbon (0.89%). A quantity of 50 cubic metres of tank silt changed the organic carbon content of soil from 0.03% to 0.40%. It has considerably increased the moisture holding capacity of the soil.
There was 63% to 200% increase in the yield of various crops when compared to the normal plot; the yield increase was 15% to 93% when compared to the control plot. The study result showed that there was notable yield increase in the treated plots, thereby giving the farmers the much needed adaptation mechanism to practise agriculture with reduced risk exposure.
Tank silt is a locally available and a low-cost substitute for chemical fertiliser. It has demonstrated its efficacy in augmenting adaptation capacity of rainfed farms to climate change in the study area. It has proven multiple benefits for climate resilient farming that can be promoted on a large scale.