Madhya Pradesh Quiz: Climate and Soils of Madhya Pradesh

The Tropic of Cancer crosses Madhya Pradesh almost through the middle, running past Ratlam, Ujjain, Bhopal, Vidisha, Sagar, Jabalpur and Shahdol, so the state is divided nearly in half by it and more districts of Madhya Pradesh are touched by the line than in any other state.

The Deccan trap basalt underlies a very large part of the state, from the Malwa plateau through the Narmada valley to Nimar and the Satpura, and its weathering has given black soil, also called regur or cotton soil, the largest share of the state's area.

The lava flows that spread over central and western India at the end of the Cretaceous left thick sheets of basalt, and when basalt weathers in a monsoon climate it yields a fine clay rich in iron, lime and magnesium, which is exactly the black soil of Malwa, the Narmada…

There the old crystalline rocks, gneiss and granite, lie at the surface, and the iron released by their weathering gives the soil its red colour, turning yellow where the iron is hydrated by heavier rain.

The reason is that the state's rain comes mostly from the Bay of Bengal branch of the monsoon, which enters from the east and weakens as it travels inland, so the farthest north-western corner is driest.

Pachmarhi sits on a plateau in the Satpura range south of the Narmada, and Dhupgarh beside it, at about 1,350 metres, is the highest point of Madhya Pradesh; the height gives the place its cool climate, its heavy rain and the biosphere reserve around it.

This is the only real alluvial tract of the state, it is the most fertile soil there and it grows wheat, mustard and gram.

The deep black soil of Malwa holds moisture through the gaps in the monsoon, which is exactly what soybean needs, and the crop spread so widely across Indore, Ujjain, Dewas and Dhar that Madhya Pradesh came to be called the soya state; the same soil also carries cotton, wheat and…

The Chambal flows north through soft alluvium towards the Yamuna, and the monsoon run-off cuts channels into it that deepen and widen every year into the badlands called bihad, which swallow farmland and once gave the region its reputation as a refuge for outlaws.

Laterite forms where heavy rain and warm temperatures wash the silica and bases out of the soil and leave iron and aluminium oxides behind, so it appears on the high rainfall plateau of eastern Madhya Pradesh, where rainfall crosses 1,400 millimetres.