Cropping system is a method of growing crops that is designed to produce high yields without weakening the soil. A good cropping system combines different production techniques to make the best use of the land. These techniques may include various cultivation methods, crop rotation (alternating the crops grown in a field from year to year), and the proper use of fertilizers and pesticides. To determine the most suitable system, farmers must consider the land’s soil composition and any slope, drainage, and erosion problems. Farmers must also know the land’s cropping history, such as any plant diseases and insect problems that have occurred there.
Crop rotation ranks as one of the oldest and most widely used methods to preserve soil. A single crop consumes vital minerals and organic matter in soil if it is grown in the same field every year. But different kinds of crops planted in the field on a regular schedule will replace lost minerals and organic matter. For example, corn absorbs nitrogen from soil. A farmer can replace the nitrogen by planting such crops as alfalfa, soybean, and clover. These plants accumulate nitrogen in their roots through a process called nitrogen fixation. Nitrogen-producing crops plowed into the soil also replace organic matter and enrich the soil when they rot. In addition, crop rotation helps prevent the spread of plant disease and disrupt the development of harmful insects.
Farmers grow deep-rooted crops, such as alfalfa and canola, to create pathways that allow water to penetrate the soil’s lower layers. On sloping land, they frequently alternate grasses and deep-rooted crops with other crops to hold the soil in place and prevent erosion.
The use of fertilizers and chemical pesticides has gradually replaced crop rotation, enabling farmers to grow the most profitable crops each year. Farmers must adjust the application of fertilizers and other chemicals according to varying soil conditions and crop needs. Scientists have modified the genetic (hereditary) makeup of some plants, enabling them to withstand the application of various chemicals. Such genetically modified (GM) crops simplify crop production but may result in weeds that also become genetically resistant to these chemicals and interfere with crop rotation.
