The creeping danger for agriculture may not be from the clouds above or the water levels in reservoirs, but from the slow death of the soil the farmer tills. In vast swathes of land in the State, organic carbon has depleted to a point where the soil cannot sustain life without extensive human involvement. Meanwhile, erosion, a result of the changes in landscape and agrarian practices, is seeing millions of tonnes of soil being washed away from fertile lands.
These disconcerting findings come from the culmination of a four-year research into the soil in drylands under the Sujala scheme, implemented by the State government with 14 agencies and with funding from the World Bank.
Over 2,500 watersheds have been mapped and a Land Resource Inventory (LRI) Atlas created for each one. The 60-page document catalogues the nature of the soil in individual watersheds and forms a background on what needs to be done to reverse the problems.
As the overall data on the 12.5 lakh hectares of drylands is yet to be made public, The Hindu analysed data on 230 watersheds across nine districts that is available to the public. These watersheds cover more than 1.2 lakh hectares and allow a peek into the distress of agrarian practices in vulnerable rain-fed areas.
While micro-nutrient deficiency is widespread — something that can be corrected with the use of the right fertilizer — there are other permanent indicators that have raised concern. For instance, take the critical nutrient of organic carbon that is an indicator of “life in the soil,” productivity and ability to trap nutrients. In over 88% of the land area, it is below the ideal level of 0.75%. More than half the land has carbon content below the ‘danger mark’ of 0.5%.
The disparity is stark in some districts: while in the fertile Chikkamagaluru district, 71% of the land area has high organic carbon content, barely 1% of the land in Tumakuru has the ideal amount or higher. “It is difficult to recover this organic carbon and ensure the soil has the capacity to hold nutrients. Even with intensive conservation farming and green manure, it may take four or five years to turn bad soil into healthy soil,” said Rajendra Hegde, principal scientist, National Bureau of Soil Survey and Land Use Planning.
Another concern is soil erosion, which erodes the top soil. With lower soil depth, the ability to retain water or nutrients reduces dramatically. The Hindu’s analysis shows that 44% of the arable land is in moderate stage of erosion, losing up to 10 tonnes a hectare annually, while it is severe or worse in 7%.
“Slight erosion will happen, but most of it is man-made. Considering that rainy days are becoming fewer in number while periods of intense rainfall are on the rise, this erosion will increase. In black soil areas (which dominate much of north Karnataka), moderate erosion can turn severe in two years or so,” said Mr. Hegde.
The combined effect of these problems is that a majority of the agricultural land is classified as Class III or below, which signifies a marked dip in productivity of land and farmers’ earnings. Combined with socio-economic factors, it isn’t a coincidence then that several studies are showing a dramatic increase in fallow land where agriculture is no longer practised.
“These are just collective impacts of decades of unsuitable agricultural practices. Agriculture has gone beyond distress to a tragic situation... soil is such a critical thing and it has been neglected for far too long,” said A. Natarajan, natural resource management consultant for the project and a soil scientist with decades of experience.
Advanced soil cards soon
On a half-acre plot, a farmer in Nagenahalli village of Tumakuru district, much like those in his 8.67 sq.km watershed, has been growing coconut over the years.
While the name of the farmer is yet to be known, his (or her) preliminary soil resources card notes that productivity would have been better if other crops were cultivated on the land. Based on the testing of the soil samples in the watershed, a comprehensive understanding of the soil and cultivation practices is reflected in the card. Coconut, it says, is just in the second level of suitability (S2 — for moderate suitability; with texture of the soil being a constraint). Instead, perhaps better yields and profits would come through S1 crops such as johar, togari, sunflower, horse gram, ragi, or horticultural crops such as mosambi, mango, and jackfruit.
Under Sujala III, these cards will be distributed to over 50 lakh farmer households in the 11 dryland districts of Karnataka. “The Land Resource Inventory (LRI) is available and all that needs to be done is to fill in the farmers’ names and distribute the cards,” said Mr. Natarajan.
The complex card packs in more details and conservation measures than the soil health card — which tabulates only micro-nutrient deficiencies — currently being distributed under a Central scheme. By the end of the year, a portal on land inventory and even ways of dissemination of soil information through mobile phones are being envisioned. Numerous outreach programmes have trained watershed committees on deciphering the information in the LRI Atlas.
While each inventory has measures to improve soil and water conservation at watersheds, the aim is to include farmers in the process. “Correcting the deficiencies in soil cannot be done through watershed infrastructure alone. Farmers are made participants and helped to grow the right crops to increase productivity and reverse some of the effects of growing unsuitable crops using unsustainable practices,” Mr. Natarajan said.
At present, policymakers use an LRI Atlas developed by the National Bureau of Soil Survey and Land Use Planning in the 1980s, which was put together on a 1:2,50,000 scale (that is, 1 cm on the map is 2.5 km on the ground). However, these new maps are on a 1:8,000 scale and allow for a plot-wise understanding of the soil.