**1. Introduction**

Globally, grasslands known by the names of prairie, savanna, steppe, and pampas in conjunction with rangeland occupy over 70% of the agricultural area of which 68% lies in the developing countries. Grasslands provide a variety of foods and forages while people also rely heavily on them for their source of earning through milk, meat, and wool production. Over time, more than 20% of the world's native grasslands have been transformed into croplands to carry out intensive farming of cash crops. There are over 1 billion of the world's poorest people depend on the livestock industry, which relies on native grasslands for animal feed. In this way, grasslands support the production of over one-third of protein requirements worldwide [1–10].

In many developed countries of Europe and North America, the native grasslands have been continuously converted into pasturelands for boosting milk production or croplands for cultivating high-yielding grain and cash crops. The extent of grasslands transformation might be realized from the fact that tall-grass prairie spreading across many states of the US has been converted to carry on intensive farming of crops, leaving behind less than 1% of the original prairie. Contrastingly, many developing countries of Africa and Asia have kept on extensively utilizing their native grasslands as a source of cost-effective feed source and watershed.
