t 37 ] 



foods as well as organic plant food, is perhaps a stiff clay 

 which he finds it difficult to dig with his spud and on the 

 surface of which he notices deep and wide cracks and though 

 he knows it to be richer he will not prefer it for ordinary 

 agricultural crops though he will for permanent pasture and 

 for such perennial crops, as Rhea, Abroma augusta, Tapioca 

 and such agricultural crops as take long growing, such as 

 arahar and sugarcane. If he can afford to keep it in pro- 

 per tilth and if there are special facilities for irrigation he 

 will prefer clay soil to loam, unless the clay is too stiff. 

 Different soils are particularly adapted for particular crops, 

 and when one cannot choose his soil one can at least choose 

 his crops. By cultivation and manuring it is possible to a 

 limited extent to alter the natural adaptability of certain 

 soils to certain crops and these should not be lost sight of, 

 in any case. Even barren Usar land has been rendered 

 fertile by proper treatment. 



38. It has been said that certain stratified rocks were 

 loose workable soil in former geological periods. Hence we 

 find imbedded in hard rocks, fossils of plants and animals that 

 once grew on the soil or disported themselves over it. As 

 the remains of animals and plants are very valuable as plant 

 food, rocks showing an abundance of fossils, such as certain 

 sandstones and all limestones are productive of very fertile 

 soils. The recognition of fossils is thus of some practical 

 importance to farmers. The fertilising property of the rocks 

 of the crystalline group, viz., archaic and metamorphic rocks, 

 consists chiefly in the presence of an abundance of Felspar. 

 Mica is of less importance and quartz is of least. All sedi- 

 mentary rocks and soils being ultimately derived from these 

 crystalline rocks, a knowledge of the composition of these is 

 of value. Mica-schist consists of quartz and mica and a soil 

 formed out of mica-schist is therefore poor. Gneiss is the 

 same as granite in composition only it is sedimentary and 

 metamorphic or become compact and crystalline by the 



