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Agriculture and The Environment
The last three decades witnessed substantial productivity increase in cereals, pulses, edible oils and cash crops through adoption of high yielding varieties and intensive application of other inputs. There has been a shift away from cereals to cash crops as and when high yielding varieties were developed. Irrigated acreage increased in all major crops.
Against the ultimate potential of 18 lakh hectares from major irrigation schemes [excluding Narmada], 3.48 lakh hectares from minor irrigation schemes and 20.21 lakh hectares from ground water resources, respectively 13.82, 2.40 and 20.21 lakh hectares were brought under irrigation by June 1999. As far as maximum utilization was concerned, out of a total of 30.95 lakh hectares [1999], as much as 17.19 lakh hectares came from ground water resources.
The percentage of irrigated area to net-cropped area at 36.32% was close to the national average of 38.33%. Fertilizer consumption went up steadily and at 105 kgs per hectare, was significantly higher than the national average of 89.9 kgs per hectare [1999]. Application of chemical pesticides and insecticides was also going up. More than 50% of these get used only for the cotton crop. By 1996-1997 virtually the entire cropped area is subject to application of pesticides and the intensity of application at 460 gms per hectare is higher than the national average.
Total fertilizer use went up from the average of 300000 tons during 1961-66 to 864000 tons during 1995-98.The increased consumption cannot be explained in terms of either increase in net cropped area, cropping intensity or additional irrigation facilities. More disturbing is the shift in favour of cheaper nitrogenous fertilizers over the years at the expense of phosphates. For instance, the share of nitrogen application increased from 63.33% in 1961-66 to 71.41% in 1995-98, accompanied by a fall of more than 10 % in the application of phosphate fertilizers over the same period i.e. from 33.33% to 23.14%. It is not clear whether nutrient requirements or other externalities determine the type or quantum of fertilizer application. A variety of factors seem to influence the application of both inputs as well as exploitation of limited resources in an unsustainable way leading to the emergence of the following environmental problems.
Soil Erosion
It was estimated in 1994 that 170 of the 184 talukas [into which the state was divided at that time] were affected by water erosion of soils in varying degrees. Of the total geographic area of the State 33.5% was found to be affected [Annexure-X]. The problem is severe in the Dangs, Bharuch, Valsad, Surat, Panchmahal and Sabarkantha districts. This could be attributed to natural factors like heavy rainfall over a short duration and hilly terrains though a correlation could also exist between high cropping intensity and erosion.
Talukas affected by soil erosion
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Soil Salinity and Alkalinity
Estimates of the total area of such degraded soils in Gujarat vary from 1.22 m.ha for the entire State (1960) to a high 3.02 m.ha in 14 districts alone. Even the lesser of the two figures is quite staggering. According to a survey conducted in 1995, eight districts, namely Kachchh, Jamnagar, Amreli, Surendranagar, Bhavnagar, Kheda, Mehsana and Ahmedabad account for 91% of the salinity affected area in the state.[Annexure-XI]
Soil Salinity In Gujarat
|
Estimated impact of soil degradation on Indian Agriculture (using 1991/92 data) | ||
|
Crop |
Percent loss |
Average value of loss (millions US$) |
| Paddy |
2.7-4.7% |
$190 |
| Wheat |
3.9-6.4% |
$248 |
| Barley |
4.5-7.0% |
$8 |
| Groundnut |
2.8-4.4% |
$110 |
| Gram |
5.6-7.8% |
$60 |
| Rapeseed & mustard |
5.8-8.5% |
$155 |
| Jowar |
5.7-7.6% |
$40 |
| Bajra |
6.8-8.4% |
$25 |
| Cotton |
5.3-6.9% |
$140 |
| Maize |
3.2-4.9% |
$25 |
| Sugarcane |
4.5-7.9% |
$200 |
| All other crops |
4.0-6.3% |
$750 |
| Total |
4.0-6.3% |
$1,951 |
| Source : The cost of inaction : Valuing the economy-wide cost of environmental degradation in India (World Bank) : 1995 | ||
Waterlogging
Excessive irrigation in command areas of irrigation projects of Ukai and Kakrapar has led to water logging and consequent salinity over 0.185 mha. This affects 52.18% of the total command area of 356080 hectares. In the Mahi command area of 212694 hectares as much as 138676 hectares representing 65.19% of the command is salinity affected. Other factors like poor natural drainage and lack of incentives for conjunctive use of water has added to the problem. [Annexure–XII]
Talukas affected by Water logging in Gujarat
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Salinity ingress
Salinity in the coastal areas is both natural and manmade. Excessive groundwater extraction has resulted in lateral sub-surface intrusion of seawater in the Bhavnagar-Una, Una-Madhavpur, Madhavpur-Malia and Malia-Lakhpat stretches and affect as much as 13524 sq km area. In Bhavnagar-Una and the Madhavpur-Malia stretch the salinity ingress has reached up to 14 km in wards from the shore. Crop yields have fallen to one-tenth to two-thirds in this belt. [Annexure–XIII]
Talukas affected by salinity ingress of coastal Aquifers
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Soil degradation from saline ground water
In the interior areas of the State, soil salinity is a direct result of over dependence on groundwater for sustaining highly intensive cropping practices. Groundwater from deeper aquifers carries with it soluble salts which get deposited on land causing salinity and fall in productivity. This scenario is being prominently witnessed in the north Gujarat districts of Mehsana, and Banaskantha.
Talukas with Severe Land Degradation due to various factors.
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Over exploitation of ground water
The overexploitation of groundwater is driven mostly by irrigation needs. More than 90% of the total cultivated area in north Gujarat is being irrigated by groundwater sources. Groundwater development has been over 100% in Banas, Saraswati, Rupen and Sabarmati basins and 93.55% in Rel basin. Groundwater balance in this region is negative. As many as 53 talukas (Annexure IX) in the districts of Banaskantha[6], Mehesana[11], Sabarkantha[2], Gandhinagar[1], Ahmedabad[3], Kheda[3], Vadodara[3], Bharuch[2], Amreli[2], Jamnagar[1], Junagadh[8], Rajkot[2], Surendranagr[2] and Kutch[6] are in the over exploited category where the drawal is more than the recharge. [Annexure–XIV]
Overexploited talukas in terms of ground water extraction
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Reduction in the groundwater recharge area
The net area suitable for groundwater recharge is seen to be decreasing in Gujarat. Between 1981 and 1988 net suitable area declined in all the districts except the Panchmahals, Sabarkantha, Gandhinagar and the Dangs. The shrinkage was more than 40% in Mehsana, Banaskantha and Rajkot, 36.34% in Bhavnagar and 30% in Ahmedabad and Amreli. These figures have a correlation with the large areas affected by salinity in north Gujarat and Saurashtra.
