The previous post was quite lucid. We might be able to tie into the decline in agriculture into the growth of other industries such as manufacturing and information technology. Both the decline of one sector and emergence of another might not be dependent on one another, but they are fairly simultaneous. One of the impacts of this convergence is that India focused and concentrated more of its wealth efforts on the industrial and modernized information technology field and moved away from its agrarian sector. The implications of this was a growth of industrialization and an almost institutional neglect of the agrarian areas. This is going to be something that India must address in the coming time frame, as India is still a rural country with so much of its population coming from areas that are not the cities. India cannot embrace its full place on the world economic stage if it does not address the vastly different experiences between rural and urban.
In 1991, India was compelled to encourage liberalization and globalization in its agricultural sector. It had to do this because of pressure from the International Monetary Fund, from whom India was seeking a loan.
It appears that the impact on Indian agriculture has been largely negative. Growth rates in the agricultural sector have been down overall, dropping by about 50 percent between 1991 and 1997. There have been some bright spots, but it seems that most of the benefit of the structural changes have been enjoyed by richer farmers.
Some researchers believe, however, that the liberalization may not be at fault and that further reforms are needed to allow Indian agriculture to flourish.
The links I've provided have a great deal of information. I'd suggest that you google "1991 liberalisation indian agriculture."