A negative result of monoculture farming is a decrease in mineral nutrients in soil.
<u>Explanation:</u>
When only one type of crop or plant variety is grown in a farming land at a certain period of time, it refers to Mono culture. It is a farming technique that is used industrial and also in organic way of farming. It is an efficient way for harvesting a particular species based on the season that supports their growth. The same way it also has disadvantages too. It can introduce many number of diseases and pests in the farming land.
The process of planting and harvesting the same plant variety in an area over a period of time will lead to the removal of nutrients that are present in that particular area. This is because the all the plants will be dependent on the same type of nutrients present in the soil and they will take that type abundantly. This will result in the eradication of that nutrient type from the soil resulting in making the soil very weak. Hence that farm area will not be suitable for growing other crops in a healthier way. This will lead to the use of fertilizers by the farmers that will again eradicate the soil nutrients.
Answer:
Selection is a directional process that leads to an increase or a decrease in the frequency of genes or genotypes. Selection is the process that increases the frequencies of plant resistance alleles in natural ecosystems through coevolution, and it is the process that increases the frequencies of virulence alleles in agricultural ecosystems during boom and bust cycles.
Selection occurs in response to a specific environmental factor. It is a central topic of population and evolutionary biology. The consequence of natural selection on the genetic structure and evolution of organisms is complicated. Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection). It can increase the genetic variation in populations by selecting for or against several genes or gene combinations (leading to disruptive selection or balancing selection). Natural selection might lead to speciation through the accumulation of adaptive genetic differences among reproductively isolated populations. Selection can also prevent speciation by homogenizing the population genetic structure across all locations.
Selection in plant pathology is mainly considered in the framework of gene-for-gene coevolution. Plant pathologists often think in terms of Van der Plank and his concept of "stabilizing selection" that would operate against pathogen strains with unnecessary virulence. As we will see shortly, Van der Plank used the wrong term, as he was actually referring to directional selection against unneeded virulence alleles.
