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close this bookAbstracts on Sustainable Agriculture (GTZ; 1992; 423 pages)
Open this folder and view contentsAbstracts On Traditional Land-Use Systems
Open this folder and view contentsAbstracts on farming systems research and development
Open this folder and view contentsAbstracts on integrated systems
Open this folder and view contentsAbstracts on cropping system
Open this folder and view contentsAbstracts on agroecology
Open this folder and view contentsAbstracts on agrometeorology
Open this folder and view contentsAbstracts on agroforestry
Open this folder and view contentsAbstracts on homegardens
Open this folder and view contentsAbstracts on seed production
close this folderAbstracts on plant protection
View the documentAcknowledgements
View the document1. Designing integrated pest management for sustainable and productive futures.
View the document2. Biotechnology's bitter harvest: herbicide-tolerant crops and the threat to sustainable agriculture.
View the document3. Chemistry, agriculture and the environment.
View the document4. Mise au point de techniques appropriées de lir qui seront utilisés par les petits agriculteurs traditionnels d'Afrique tropicale.(developing appropriate ipm technology for the traditional small-scale farmer in tropical Africa).
View the document5. Biological control in developing countries: towards its wider application in sustainable pest management.
View the document6. Transforming plants as a means of crop protection against insects.
View the document7. Utilization of va-mycorrhiza as a factor in integrated plant protection.
View the document8. Activity of four plant leaf extracts against three fungal pathogens of rice.
View the document9. A useful approach to the biocontrol of cassava pathogens.
View the document10. Evaluation of the biological activity of flax as a trap crop against orobanche parasitism of vicia faba.
View the document11. Insect pest management.
View the document12. Economic contributions of pest management to agricultural development.
View the document13. The effects of intercropping and mixed varieties of predators and parasitoids of cassava whiteflies (hemiptera: aleyrodidae) in Colombia.
View the document14. Prospects for traditional and cultural practices in integrated pest management of some root crop diseases in rivers state, Nigeria.
View the document15. Studies on cowpea farming practices in nigeria, with emphasis on insect pest control.
View the document16. Effect of various fertilizers and rates on insect pest/pearl millet relationship in Senegal.
View the document17. Insect pests of intercrops and their potential to infest oil palm in an oil-palm-based agroforestry system in India.
View the document18. Using weather data to forecast insect pest outbreaks.
View the document19. Insect pest management and socio-economic circumstances of small-scale farmers for food crop production in western Kenya: a case study.
View the document20. Rodent communities associated with three traditional agroecosystems in the San Luis potosi plateau, Mexico.
View the document21. Grain storage losses in Zimbabwe.
View the document22. Controlling weeds without chemicals.
View the document23. Weed management in agroecosystems: ecological approaches.
View the document24. Manual on the prevention of post-harvest grain losses.
View the document25. Evaluation of efficient weed management systems in pigeonpea (cajanus cajan l.)
View the document26. Weed management in a low-input cropping system in the Peruvian Amazon region.
View the document27. Poblaciones, biomasa y banco de semillas de arvenses en cultivos de maiz zea mays l. Y frijol phaseolus vulgaris l. Efecto de m+todos de control y rotaciones. (Weed population, biomass, and seed bank in maize and bean crops. Effects of control methods and crop rotations).
View the document28. Effects of groundnut, cowpea and melon on weed control and yields of intercropped cassava and maize.
View the document29. Intercropping and weeding: effects on some natural enemies of African bollworm, heliothis armigera (hbn.) (lep., Noctuidae), in bean fields.
Open this folder and view contentsAbstracts on water management
Open this folder and view contentsAbstracts on soil fertility
Open this folder and view contentsAbstracts on erosion and desertification control
Open this folder and view contentsAbstracts on potential crops for marginal lands
 

22. Controlling weeds without chemicals.

The Cultivar, 9, No. 2, 1991. pp. 1-3

Herbicides make up 69% of the 700 million pounds of pesticides applied each year in the U.S. Thus, finding alternative methods for controlling weeds is critical to decreasing the use of synthetic chemicals in farming systems.

Weeds can be controlled in small-scale vegetable row crop systems without the use of herbicides and with a minimum of hand hoeing by using an integrated approach. This includes well-managed ground preparation and planting techniques, and timely cultivations. Planting and cultivation techniques that large-scale growers have used successfully for many years can be easily adapted to small- and medium-scale systems for effective weed control.

Small-scale vegetable growers - especially those who are producing for direct-market, roadside, or specialty markets - often must produce a variety of products over a period of time to maintain a customer base and maintain diversity.

One of the best ways to deal with multiple crops on a small scale is to develop a system where all crops are planted on the same row width. The same planting and cultivating units can then be used for all crops without a loss in time due to change-over. A common technique, which can be traced back to the horse cultivar, is to plant cultivate on a single line per bed with beds spaced 30 to 38 inches center to center. This technique allows for the greatest crop diversity and ease of mechanical weed management in a ridge-tilled system. If beds are formed, pre-irrigated and then cultivated prior to planting, weed pressure can be minimized and planting and cultivation simplified.

Vegetable crops most suited to between-row spacings of 30 to 38 inches include sweet corn, beans, potatoes, peppers, broccoli, cauliflower and cabbage. With the proper planting equipment, sweet corn, beans and peas can be easily direct-seeded to moisture by knocking down the beds at planting time (this entails pushing dirt off of the top of the bed to reach moist soil; seeds planted into moist soil don't require irrigation for germination). Peppers, tomatoes and the brassicas mentioned above are ideally suited to transplanting, provided quality transplants are used. Tomatoes, which require a wider spacing, can be grown on every other bed and the same cultivation equipment used. If perennial weeds are not a serious problem, and with proper management, these crops can all be produced in a relatively weed-free system with minimal hand labour and no herbicides.

One of the most effective tools for post-irrigation bed preparation and post-emergence crop cultivation in a ridge-tilled system is the ground-driven rotary cultivator, also known as a lilliston cultivator.

For the initial cultivation, while the crop is still small, reversed disc-hillers can be used to cut soil away from the plants, and sweeps and knives can be used to cut weeds off just below the soil surface.

Timing in terms of weed size and soil moisture are critical at this stage for optimum weed suppression: ideally, weeds should be small and the soil dry enough to that weeds don't re-germinate, but moist enough to avoid crusting.

The following practices are the most important factors to include in a non-chemical weed control strategy:

 

- Allow an initial fallow period with repeated discing during summer months to bring perennial weed populations to manageable levels.

- Rotate cool-season and warm-season crops and rotate crops that compete well with weeds and those that are poor competitors.

- Prevent annual weed seed maturation in and around fields.

- Pre-irrigate after bedding-up to germinate weed seeds prior to planting.

- Carry out timely shallow cultivations to destroy weed seedlings during and after emergence.

- Plant to moisture to allow crops to get a jump on weeds.

- Transplant where practical to get a jump on weeds.

- Manage irrigation effectively.

By adhering to and integrating the above-mentioned agronomic practices, and by using rotary ground-driven cultivators in a single-line system, weeds in vegetable crops can be controlled effectively and economically without the use of herbicides.

1216 92 - 10/143

Plant protection

Review, book, weed management, ecological approaches

ALTIERI, M.A. and M. LIEBMANN

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