Harare — CONSERVATION agriculture has become popular with most communal small-scale farmers as some non-governmental organisations are spearheading the farming method they say is more sustainable than the usual way of farming.

Conservation agriculture is based on minimum soil movement (by tillage), soil surface cover with crop residue and living plants and crop rotations to avoid pests.

The system can be used by farmers under a wide range of soil types and environments and can be used in the production of numerous crops.

However, the technique does not work well on waterlogged and very dry conditions.

Conservation specialist Mrs Lungowe Sepo Marongwe said maize, wheat, soyabeans cotton sunflower, rice and tobacco could be grown under conservation agricul-ture.

"Even root crops, including potatoes and cassava, can also be grown under conservation agriculture. Some of the benefits of conservation agriculture are increased water infiltration, reduced evaporation and increased water available to crops," she said.

Since more water goes into the soil (increased infiltration) less water runs off the land and is available to the crop.

This gives the crop more chances of survival even under dry spells.

Kadoma district agritex extension officer, Mrs Evelyn Ndoro said the method was also good as it reduced weed and crop competition for nutrients.

"Fertilizer is applied in the planting stations and will only be available to the crop," she said.

According to CIMMYT, if tillage is carried out, rains will disturb the soil causing it to seal the surface and reducing water infiltration in the process.

Surface crop residues (crop remains) protect the soil surface not only from raindrops but also from sun's rays.

Crops residues also help improve nutrients in the soil and also reduce weed germination and growth.

The method is, however, labour intensive especially the first time, as farmers have to establish planting stations. The planting stations (holes) are renewed every year.

Land preparations for conservation agriculture can be done both manually and mechanically.

Manual seeding of crops into residues, according to CIMMYT, is relatively easy and can be done by several methods including hoes or pointed sticks, digging of basins or using machinery such as jab planter.

The simplest of these is the use of hoe or pointed stick.

Small hoes are made at the required spacing of about 15 by 15cm and 15cm deep in rows that are 75-90cm apart and with 50-60cm between the basins in the row.

Basins are dug manually using a hoe during the winter period so that labour is distributed over a long period and farmers are able to plant with the first effective rains.

However, basins require considerable labour in the first season when soils can be very hard.