This would <span>be caused</span> by a reversal of the temperature in the troposphere<span> (the region of the atmosphere nearest the Earth's surface), in which a layer of cool air at the surface is overlain by a layer of warmer air.</span>
Every year the farmer was taking care of his ice field, keep it clean and clear of all the unnecessary shrubs and then reuse the debris to fertile the soil again and then grow rice again. But since he fell sick, there is no one to take care of his rice field which will leads to the growth of unnecessary plants and weeds in it.
There will grow wild plants and shrubs which will contaminate the rice field.
Gause's Competitive Exclusion Principle
The 'competitive exclusion principle' (CEP) states that two species with identical niches cannot coexist indefinitely. ... Gause helped propel ecology by his approach of experimentally testing mathematical models, and his unifying the concept of the niche with resource competition.