Crop rotations types

Different types of management may be developed for weed, insect, and disease control, for crop rotation, and for agroforestry employing allelopathy. In the following paragraphs these are discussed separately. 

Eriksen, J., Askegaard, M. and Kristensen, K. 2004. Nitrate leaching from an organic dairy crop rotation the effects of manure type, nitrogen input and improved crop rotation. Soil Use and Management 20 48-54. 

Plants belonging to 57 families have been shown to possess nematicidal properties (Bridge, 1996). Crop rotation (crops planted in sequence) and intercropping (crops planted together) have both shown potential for reducing populations of parasitic nematodes. Cover crops are a type of rotation employed as an alternative to leaving land fallow, and are usually not cash crops. Many plants have been used as rotation or cover crops for plant-parasitic nematode control (Table 1). 

For each county in the 10 states evaluated, all cropland soil types in land capability classes (LCCs) I—VIII are identified. For each individual soil type, acres of that particular soil type, field topology characteristics (percentage low and high slopes), erodibility, and tolerable soil-loss limit are obtained from the USD A. These data are used in the rain and wind erosion equations described later. In each of the states analyzed, the following crop rotations are considered (where applicable) continuous corn, corn-soybean, corn-winter wheat, corn-spring wheat, continuous winter wheat, winter wheat-soybeans. 

Crop rotation also helps interrupl pathogen life cycles, especially for those diseases that only attack certain types of hosts. For more details on how crop rotation can control disease, see Rotate your crops" below. 

As a cultural practice, crop rotation does more than control infectious diseases. It also helps control certain insect pests and is valuable for avoiding nutrient disorders. Growing different types of plants each year at a given location prevents the soil from being selectively depleted of the nutrients utilized by one type of plant. Instead, a spectrum of nutrients is removed from the soil over time, which generally tends to maintain balanced fertility. 

Soil Health. To support a crop with the highest possible yields, the soil in which the seeds are planted must be in good condition and must match the needs of the particular plant breed. The health of soil can be measured on the basis of its physical properties, its chemical makeup, and the biological material it contains. These qualities are tracked by soU surveys that are conducted and published regularly. Many formers switch the types of crops they grow in a particular field every few years in order to keep certain soil nutrients from being depleted. This practice is known as crop rotation. 

The range of crops, often with autumn- and spring-sown varieties, offers an option for most soil types, pH and crop rotations. Seasonal weather may adversely influence crop establishment, harvesting and sample quality. Home-saved seed has been an option for some of the crops but with specific quality requirements for the harvested product, and a trend to lower seed rates/plant populations, high quality seed with an appropriate treatment is advisable. 

---