[This para. has been written by Mr. Plymen, Agricultural Chemist.]
95. The District lies towards the eastern boundary of the
Deccan trap area and hence the soils of the District are either true
black cotton soil or else formed from a basis of cotton soil modified by intermixture with soils derived from the gneissic formation which surrounds it. This black cotton soil or regar determines to a large extent the nature of the agriculture of the District. There is no general agreement as to how this wide expanse of regar has been formed. Its character is that of an alluvial backwater or lake deposit, but it is difficult to see how such a formation can have occurred on the Deccan plateau. In many places there is no doubt that the soil is derived by the disintegration of basaltic trap rock and in others by the decomposition of other argillaceous rocks. That the process of regur
formation is a superficial one can be well seen in the undulating country of the Nagpur District. On the tops of the fiat hills where the surface suffers less from erosion than the sides, the soil is dark brown in colour. That upon the sides of these hills being more recently formed is reddish brown, while in the valleys below, where the rain-wash gradually accumulates, the soil becomes of a true black cotton-soil colour. It is largely as a result of this erosion and subsequent accumulation that the agricultural value of the land of this District varies so enormously.
The origin of the black colour is also a question of doubt. It is generally ascribed to the presence of organic matter, but this material is scarcely present in sufficient quantity to account for the blackness altogether and it is quite possible
that some of the colour at any rate is due to mineral matter. Chemically, black cotton soil shows no very striking differences from other Indian soils. The proportions of iron, alumina,
lime and magnesium are fairly high, particularly the latter; while of the more essential plant foods, potash appears to be present relatively in more abundant quantity than phosphorous and
nitrogen. If compared with English soils the amounts of phosphates and nitrogen do certainly appear to be small and this fact has doubtless given currency to the idea that the black cotton soil is becoming impoverished. With the exception, however, of certain alluvial deposits in Assam this soil compares favourably with the generality of Indian soil in this respect. Physically regar is essentially a clay soil and as such is very sticky when wet, retentive of moisture and easily loses its tilth if cultivated at the wrong time. The presence of lime, however, to a certain extent counteracts these qualities and renders the soil friable when dry besides giving it its host characteristic property,-that of shrinking and cracking. This property is due to flocculation of the clay particles in the presence of a dilute solution of some lime compound, but the contraction thereby caused only become apparent when the soil dries. The best regar land contains very few large particles, but inferior qualities frequently contain nodular limestone or kankar. This deposition of a calcareous pan is of general occurrence in soils of arid regions. In the east of the District the underlying rock is crystalline and yields a soil more sandy and pervious than regar and one therefore more adaptable to irrigation. Where the two geological formations intermix a free working loam is obtained, but this is not found over any large area.
96. The best deep black soil, known as kali, occurs only
in small areas, covering altogether
less than two per cent. of the cultivated area. It is found round Kalmeshwar and Saoner, in the Wardha valley and in the Nagpur and Kamptee plain.
The principal soil of the District is that known as morand, under the two classes of which come two-thirds of the cultivated area. It is of comparatively slight depth, dark to light brown in colour, of light texture and easily culturable, and containing a greater or less quantity of limestone pebbles (kankar). This soil is eminently suited to cotton and juari and makes excellent rice land when embanked, requiring but little irrigation if the rainfall is normal, and producing a second crop. In the northern part of the Ramtek tahsil, and especially in the valley of the Sur river, the morand soil is of very light colour.
Khardi is the term used for shallow soil not more than a cubit deep, but various qualities of land were classified under this designation as being of equivalent value. It is applied to
soil much mixed with sand and hence of a greyish colour, and also to the sandy soil formed from crystalline rock, which constitutes the regular rice land and is elsewhere known as sihar and matasi. About 27 per cent. of the cultivated area was classed as khardi. The only remaining soil of any extent is the red gravel covered with boulders, found on the summits and slopes of the trap hills. This is known as bardi and covers 5½ per cent. of the cultivated area, occurring principally in the Katol tahsil. The land under crops thus contained at Mr. Craddock's settlement a very small quantity of the really poor soil which requires resting fallows. Small stretches of retari or sandy soil overlying sandstone rock occur in the north of the Ramtek tahsil. About 1260 acres were classed as kachhar or alluvial land fertilised by the deposit of silt, the largest patch of which is in the bed of the Kanhan at Neri.
97. The usual allowances were made for advantages
and disadvantages of position. Fields recorded as pathar, hilly, or
wahuri cut up by erosion, amounted to about 14 per cent. of the better-class land or that classified as capable of growing wheat. Nearly two-thirds of the
cultivated area of 1,300,000 acres fell into this category, the bulk of the remainder being of somewhat inferior quality and known as minor crop land. Distinctions of position were not applied to this latter area; otherwise no doubt many fields in the Katol tahsil, where the surface is noticeably undulating, would have been classed as yoghurt. As it was most of the land subject to injury from erosion lay in the Umrer tahsil. Land classed as ran, or subject to the depredations of wild animals, is common in the villages near the hills in both Nagpur end Umrer.
The embankment of land is regularly practised only in certain level areas along the. Bhandara border in order to enable a broadcasted rice crop to be grown with a spring crop to follow. Elsewhere embankments are made only at field corners or along one side of a field to protect it from erosion. Out of 820,000 acres of land recorded as capable of growing wheat, 640,000 or nearly four-fifths were classified under the ordinary or sadharan position; Mr. Craddock was of opinion that in future it would be desirable to have a separate class for level or saman fields distinguishing them from ordinary fields, which are not quite level but yet of not so irregular a surface as to be recorded as hilly or cut up by erosion.
98. About 29,000 acres only were recorded as rice land,
and of this a half was classed as
capable of irrigation, though in-ordinary years so large an area is not actually irrigated. This bulk of the remainder is shown as saman or level, high-lying land not being as a rule cropped with rice. Although the rice land is of trifling extent, some villages in the west and in the Dongartal
tract are entirely dependent on this crop.
99. Minor crop land covered 460,000 acres or rather
more than a third of the cultivated area. Although this designation
is meant to indicate inferior quality either from disadvantage of position or shallowness of soil, it includes much valuable cotton and juari land in the Katol tahsil and elsewhere. About 17,000 acres were classed as garden land. A total of 15,000 acres distributed among the different classes was recorded as kharior land manured
by the drainage of the village.