Problems of soil erosion and degradation in Maharashtra

Problems of soil erosion and degradation in Maharashtra

Konkan Region

This region is located between 1;044′ and 20°20′ N lat. and 700 10′ and 730 50′ E long. with a longitudinal distance of 500 krns and a width of 15-20 kms. It comprises of four districts, namely Sindhudurg, Ratnagiri, Thane and Raigad. The northern part of the Konkan coast bas a narrow alluvial belt and relatively flat residual hill tops of lateritic exposures. The southern part bas rugged topography with steep hills, ridges, plateaus and valleys. The rock formations in the region are: Deccan trap, granites, gneisses and laterites.

Th west flowing streams originated from Westernghats flow and meander their way forming very narrow steep sided valleys along their short courses. Due to this, the coast line is broken. At places the creeks, hills and crescent shaped beaches form the coast line. Konkan region receives an average rainfall of 2500-4000mm mostly through southwest monsoon during the months July to October. The rainfall is of high intensity with total rainy days ranging from 73 to 101. The rainfall and rainy days generally increased from northern region to southern region.

Physiographically this region could be divided into coastal lands with residual hills, undulating lands with mesa and narrow valleys, undulating and rolling lands, elongated ridges and hills, uplands with narrow valleys and valley lands. The coasta1lands near the creeks are covered with moderately deep, saline, calcareous, neutral to alkaline, clayey soils while the residual hills with moderate slopes have shallow to very shallow, well drained soils of lateritic nature. These soils are skeletal and intensely leached.

The moderately sloping undulating lands with mesa support shallow to moderately deep, slightly acidic (PH 5.5 to 6.5), loamy soils. They are moderate to severely eroded and show moderate stoniness. The mesas and steeply sloping side slopes of the undulating lands support very shallow, well drained, loamy, moderately to slightly acidic (pH 4.5 to 6.5), soils with a lithic contact within 50 cm of the surface; at places low base status, loamy well developed soils (Haplustalfs) with moderate to severe erosion and strong stoDiness are observed. The narrow valleys support moderately to gently sloping, moderately shallow to deep, well drained, loamy, slightly acidic to neutral (PH 5.5 to 7.5) soils. Gently sloping valley lands develop moderately deep to deep, well drained, loamy to clayey, neutral (pH 6.5 to 7.5) soils. The soils are slightly eroded. Moderately steeply to very steeply sloping undulating and rolling lands develop well drained, loamy-skeletal, neutral (pH 6.5 to 7.5) soils and have a lithic contact within 50 cm of the surface. They are severely eroded and are moderately stony. MOderately steeply to steeply sloping spurs consist of very shallow to shallow. excessively drained, loamy, soils with severe erosion and strong stoniness (Lithic Ustorthents). These lands also have the rocky exposures at places. Gently sloping tops of the spurs also consist of moderately deep, moderately well drained, neutral (pH 6.5 to 7.5), slightly calcareous at places, clayey, cracking soils with moderate erosion. Moderately sloping uplands consist of deep, well drained, neutral (PH 6.5 to 7.5) clayey to loamy Typic Haplustepts with severe erosion and slight stoniness.

The valley slopes consist of extremely shallow, well drained, slightly acidic (pH 5.5 to 6.5) loamy, Lithic Hapiustepts and rocky exposures at places. These soils are moderately to severely eroded. Moderately steeply sloping dissected hills and intervening valleys consist of very shallow to shallow. well drained to somewhat excessively drained, slightly acidic (pH 5.5 to 6.5) loamy, Lithic Ustorthents and Lithic Haplustepts with moderate to severe erosion. Very gently sloping valley lands at places consist of moderately deep, moderately well drained, neutral, clayey, cracking soils with moderate erosion.

The severity of erosion in different districts vary and it is high  in Raigad and Sindhudurg districts as compared to Thane and Ratnagiri districts. This is mostly due to high intensity of rains, deforestation. faulty land use practices like shifting cultivation and overgrazing.

Western Ghat Region

This region forms the western edge of the Deccan plateau with several basaltic lava flows and are commonly known as Sahyadris. It includes t he hilly terrain in the districts of Dhule, Nasik, Ahmednagar, Pune, Satara, Kothapur, Sangli, Raigad, Ratnagiri and Sindhudurg. It lies between the Konkan coast and the Deccan plateau at 16°30′ and 21°31′ latitudes and 73°50′ to 74°10′ longitudes. This chain of mountains are extending from south of Tapi in Gujarat to the tip ofPenninsula and form a physical and cultural barrier between plateau and coastal low lands. The western edge of the plateau ends abruptly with an escarpment of 600 m, descending to the Konkan region. These have a crest zone of 15 to 25 km width with dissected hill ranges of precipitous slopes and narrow steep sided valleys.

Upper Maharashtra (Deccan) Plateau

East of Sahyadris, the vast plateau surface shows a declining height towards northern periphery and eastern side of the state. Upper Maharashna (Deccan) Plateau consists of the areas in Nasik, Aurangabad, Jalna, Ahmednagar, Beed, Latur, Pune, Satara, Sangli districts and some eastern tahsils of Kolhapur district. The plateau lies between 16°10′ to 20°05′ N latitudes and 741)10′ to 73°30′ E longitudes and is running south east. It is interspersed with hill ranges like Mahadeva and Ajanta and with mesa and butte, and broad valleys in between. It has gently sloping to very gently sloping plains. The broad valley lies between Ajanta and Mahadeva plateaus with eroded pediment followed by depositional piedmont merging to flood plains of Godavari, Bhima and Krishna rivers. Tapi basin is an asymmetrical valley bounded by Satpudas in the north and Ajanta ranges in the south. The valley lies in extreme northern part of the state. The rocky and rugged terrain of Satpudas and the river Narmada forms the northern border of the state. The Satpudas in the north have steep slopes and have general elevation of 1000 m above MSL. These are dissected by the tributaries of the above rivers. From north to south the Satpudas can be divided into Arkani hills, Kathi, Dahadgaon plateau and Astamba dongar. This region covers the rain shadow and rain scarcity zones of subdued hills at higher elevation, plateau of Ajanta, Balaghat, Harishchandra and Mahadeo ranges on the eastern side of Western Gahts and the interhilly basins. It receives 450-700 mm rainfall through south west monsoon and covers the rain shado”” area of the state. The important parent materials are basalt and alluvium near flvers.

Steeply to moderately steeply sloping summits and spurs consist of very shallow to shallow, excessively drained, slightly acidic to neutra (pH 5.s to 7.5), loamy-skeltal Lithic Ustorthents usually associated with rock outcrops. These soils are severely eroded and have strong stony surface. Moderately sloping spurs are covered with extremely shaJJow to very’ shallow, excessively drained, slightly acidlc to neutral (pH 5.S to 7.S), loamy-skeletal to clayey-skeletal Lithic Ustorthents and Typic Haplustepts associated with rockout crops. Gently to very gently sloping spur and summit tops consist of very shallow to shallow. well drained, neutral (pH 6.5-7.5), dayey-skeletal, Lithic Ustorthents and Typic Haplustepts with moderate erosion. At places, cracking. calcareous, clayey Typic Haplustepts and Vertic Haplustcpts with high waler holding capacity are also observed. Moderately and moderately steeply sloping undulating lands with mesa and buttes  are covered by extremely shallow to very shallow, excessively drained. loamy to clayey-skeletaL neutral (pH 6.5-7.5) at places calcareous Lithic Ustorthents with severe erosion and strong storuness. Gent}y sloping undulating lands consists of very shallow, somewhat excessively drained, loamy, calcareous, and at places non-calcareous, neutral (pH 6.5-7.5) Lithic Ustorthents and shallow. well drained, clayey Typic Haplustepts with severe erosion and moderate stoniness. At places. deep Udic Rhodustalfs with moderate erosion and deep, calcareous, cracking, Vertic H<lplustepts and Typic Haplusterts with high water holding capacity are also 10 bserved. Moderately sioping undulating lands with occassional mesas and buttes consist of very shallow, excessively drained to somewhat excessivel drained, neutral (pH 6.5-7.5) loamy-skeletal to clayey-skeletal Lithic Ustorthets with severe erosion and strong stoniness. These soils are associated with rockout crops at places. Moderately sloping pJain lands consist of shallow well drained. loamy. neutral (pH 6.5-7.5) Lithic Ustorthents with very severe erosion and stigh\ stoniness associated moderately deep, well drained, neutral. clayey (pH 6.S-7.5) Typic Haplustepts with moderate erosion and slight stoniness. Gently sloping plains consist of very shallow to shallow, well