Restore carbon content to improve soil health

Anantapur: Massive degradation of natural resources and extensive changes in land uses resulted in poor crop productivity in the Rayalaseema region, a study says. Soil organic carbon (SOC) is crucial for maintaining soil quality and sustainability in arid ecosystem.

SOC is a powerful tool for estimation of soil quality and crop productivity in arid and semiarid environmental conditions. Conversion of forest and grassland to agricultural land may cause poor carbon stock. Land and cropping system conversion are one of the most important human activities directly influence biodiversity and their functions.

Arid regions are complex, diverse, fragile, risky and require regionally differentiated climatic and crop management strategies.

The reason for low organic carbon content in these soils may be attributed to the prevalence of semiarid conditions, where the degradation of organic matter occurs at a faster rate coupled with little or no addition of organic manures and low vegetation cover on the fields, there by leaving less changes of accumulation of organic carbon in the soils. Intensive cropping is also one of the similar reasons.

Sand dunes appear in some parts of district in Rayadurg region including Dargah Honnur and Bramhasamudram. "Soil quality is worsening every year. We are losing more moisture than we get through rains," stated Dr M Virupaksha Reddy, a progressive farmer from Guntakal. In drylands like Anantapur, the annual potential evapotranspiration (PET) — the evaporation in case sufficient water source is present — exceeds annual precipitation. This has worsened the soil quality, increasing desertification.

PET defines the amount of evaporation that would occur if a sufficient water source were available. The moisture index of the district is -75.5 per cent. One of the reasons for this poor soil quality is dwindling rainfall over the region. In the last three decades, scientist have noticed that the region is witnessing increasing dry spell, erratic rainfall and 80 per cent reduction in the soil water retention capacity, says Dr Suresh.

All these show that immediate need to concentrate on contingency crop planning and drought preparedness. Borewells are also responsible for this increasing aridity. There are 2,84,000 borewells in the district of which only 59,000 borewells now functioning.

This aridity has deteriorated soil productivity. New initiatives should be taken for restoring carbon content in soil to mitigate climate change, improve soil health and maintain sustainable productivities with the help of conservation agriculture practices.