Question

Which one of the following is a characteristic feature of the cropland ecosystem?
(A) Absence of soil organisms
(B) Least genetic diversity
(C) Absence of weeds
(D) Ecological succession

Answer 1

Hint:Crop land is nothing but the land used for growing crops and we also call it as agricultural land. Man has been doing his best in modifying the croplands to get maximum benefit out of them.

Complete answer
This is an engineered or man-made ecosystem specifically aimed at developing a single species of one's choosing. A signature feature of the cropland ecosystem is the reduced genetic variation. Man has done his utmost to change the croplands to get full value from them. This includes the addition of fertilizers to the soil, the application of pest control agents, good irrigation methods, etc. Crops such as wheat, maize, rice, sugarcane etc. can represent a cropland ecosystem.
So, the correct answer is least genetic diversity.

Additional information:
Cropland ecosystem has following components:
1. Producers: The producers of a cropland ecosystem are a crop along with the weeds which grow in the field. Weeds like Cynodon dactylon, Euphorbia hirta, Alysicarpus and Launaea nudicaulis are very widespread in the maize cropland ecosystem.
2. Consumers: The primary consumers of the cropland ecosystem are herbivores. This includes rodents, rabbits, birds, insects and man. Consumers of the second order and the third order are represented by insects, rodents, birds like hawks etc.
3. Decomposers and transformers: Common decomposers and transformers of maize cropland habitats are bacteria and fungi such as Bacillus, Aspergillus, Agaricus, Mucor, Clostridium, and Fusarium.

Key issues related to natural resources for croplands include:
(1) Wind and water erosion, and
(2) To preserve and improve the consistency of soil
(3) Water quality from nutrient and pesticides runoff and leaching

Note:There are two subcategories of cropland: cultivated and uncultivated. Cultivated cropland involves land in row crops or close-grown crops, as well as other crops such as hay or grazing land in a rotation of row or near-grown crops. Non-cultivated cropland consists of permanent hay and horticultural land.