Non-chemical methods of weed control

Weeding is an important but physically demanding chore mostly performed by women. Although many experts recommend chemical methods of weed control, chemicals pose serious hazards to human health and the environment. Therefore, nonchemical, less hazardous, yet less laborious methods should be considered.

Weeds are plants which compete with crops for water, nutrients, and sunlight. They are hardy, with deep root systems, and produce many seeds which, in some cases, remain dormant and viable for decades.

Controlling weeds Weeds can be controlled through proper management, using simple implements and biological methods.

Proper crop management

1 Place fertilizer on the ground near the stem of crop plants. This will give nutrients only to the main crop, rather than to weeds.

Place fertilizer on the ground near the stem.

2 Keep channels clear of weeds. This will reduce the number of weed seeds washed into your crop. It will also keep the water flowing freely. Good irrigation practices give crops a good start over weeds.

3 Grow crops in proper rotation to keep weeds down. Two to three short-duration crops should be grown in rotation in the same field. Change the crop rotation periodically (after a few years) to prevent problem weeds from establishing. Grow at least one soil-maintaining legume crop in each rotation If a problem season is expected, select a crop which will prevent weeds from growing.

4 Clean your seed to remove weed seeds. Destroy the weed seeds by burning or burying them.

5 Major sources of weed seeds are farmyard manure and compost. Weed seeds withstand partial decomposition. Therefore, apply only fully decomposed farmyard manure or compost to your fields.

Mechanical methods

Irrigate your field a few days before sowing the crop. Plough the field to destroy the weeds that emerge before sowing the crop.

Implements make weeding easier.

2 A few implements are available which make weeding easier. Among these are the wheel hand hoe and Triphali. (See Drudgery-reducing implements for farm women.)

3 Burn weeds to get rid of accumulated vegetation or destroy dry tops of mature weeds. Burning will kill even green weeds and will destroy buried weed seeds.

4 Mulch the crop by spreading dry or green crop straw, sawdust, bark dust, and other plant parts. Paper, plastic sheets, or polythene films are also used as soil covers. This method is effective against annual and perennial weeds.

Mulching discourages weeds.

5 Flooding is used for weed control in fallow rice fields. Surround the weed-infected area with dikes, and maintain the water at 15-30 cm depth for 3 to 8 weeks.

Biological weed control

1 Some crops which grow rapidly have an advantage over slow-growing or late-emerging weeds. Such crops include maize, sorghum, soybean, and cowpea.

Slow growing weeds.

2 Weeds face tough competition when the crop plant population is high. Plant population can be increased by reducing the row spacing or plant-to-plant spacing within the row. This has a smothering effect, reducing weed emergence and establishment.

Maintain high plant population.

3 Bio-control agents, like azolla, can also be used to control weed populations in rice fields.

Azolla

Contributor. Dr. V. M. Bhan