Trap crops are grown as a control measure to lure pests away from the cash crop to protect it from attack. Pests are either prevented from reaching the crop or concentrated in certain parts of the field away from the main crop. Plants produce chemicals, or volatiles, that attract insects for pollination and repel pest insects. Different species and cultivars produce varying degrees of unique volatiles, allowing certain species or varieties to repel insect pests more strongly than others, making them suitable for selection as a trap crop.
Each of the plant species offer different attributes during the course of their growth from planting to senescence. They mature at different times offering the preferred food source - the seeds- to stink bugs at different times over the course of the 60 to 90 day maturation period. Buckwheat attracts all of the main pest species during the late flowering and seed formation stage three to five weeks after planting. Sorghum and millet are most attractive to the bugs when the seeds are in the milk stage. Following destruction of the seed heads by the bugs and seed maturation, the sorghum, millet and buckwheat can be ratooned to about 0.25 to 0.50 m in height. The millet and sorghum respond well to this technique and reform seed heads in about three to four weeks.
The two primary techniques utilized in trap cropping are:
1. selection of a more preferred plant species or cultivar grown at the same time as the main crop.
2. planting of the same species and cultivar as the main crop timed to be at the most preferred stage of development before the main crop.
When trap crops successfully attract pest populations, damage to the main crops is limited; therefore, main crops seldom require treatment with insecticides. Trap crops may also be designed for nematodes and fungi that cause plant diseases. The required size of the trap crop is a function of the number of pests expected and the mobility of the species, but the proportion of the trap crop is typically 10-20 percent of the main crop. For enhanced control, the use of trap crops can be combined with other pest management strategies, such as crop rotations, to reduce the number of expected pests, and pheromone traps, to attract pests to desired areas away from the main crop. Trap cropping is only beneficial when fields are likely to be invaded with high numbers of pests.
Intercropping offers farmers the opportunity to engage nature's principle of diversity on their farms. Spatial arrangements of plants, planting rates, and maturity dates must be considered when planning intercrops. Intercrops can be more productive than growing pure stands. Many different intercrop systems are discussed including mixed intercropping, strip cropping and traditional intercropping arrangements. Pest management benefits can also be realized from intercropping due to increased diversity. Harvesting options for intercrops include hand harvest, machine harvest for on-farm feed, and animal harvest of the standing crop.
When designing an intercropping scheme, there are four components to consider:
- spatial arrangement
- plant density
- maturity date
- plant architecture
Benefits of trap crops and intercropping:
- Reduce damage to cash crops/li>
- Attract beneficial organisms
- Decrease the use of external inputs (e.g., insecticides, herbicides, fungicides)
- Enhance biodiversity
- Enhance biodiversity
- Increase productivity
Companion planting refers to the establishment of two or more species in close proximity so that some cultural benefit, such as pest control or increased yield, may be achieved. Companion planting is a method of mixed intercropping most often used in small gardens; other methods of intercropping, such as row or strip intercropping, are intended for agricultural production at a larger scale, allowing for use of machinery. Interactions between plants can take several forms; they may be either beneficial or detrimental.
Social & economic advantages of multiple cropping systems:
- Dependence on only crop is avoided./li>
- Less needs to import energy.
- Reduction in the outlay for fertilizers.
- There is much greater flexibility of the distribution of labor.
- Possible to recover investments in much less time.
- Availability of harvest over a much longer period of time.
- Can occupy much more labor.
- The farmer of little economic resources can produce a large variety of useful products.
- Promote a return to the land.
- Components can constitute a type of "savings" for the future.
Note: Our system resulted into increase by 50% to 90% in harvest in all major fruits and 2 to 3 times more in assorted vegetables.