SOIL management encompasses a wide range of practices that ensure sustainable utilisation of the soil resource. The following aspects need to be managed for sustainable crop production: soil nutrients, soil water and soil biota (organisms). An interaction of these aspects determine the productive capacity of soils. It is important to conduct soil tests before any cropping programme.

Importance of soil testing

A soil test determines:

• Amount of nutrients available for use by the intended crop.

• Soil conditions ( for example acidity, salinity, compaction) that may enhance or hinder crop productivity.

• Management interventions that will allow for profitable agricultural production.

• An advice emanating from a robust soil test tells the farmer:

(i)Whether a soil requires lime for correcting acidity (low pH).

(ii) What type of lime (calcitic or dolomitic) should be applied and in what amounts.

(iii) What type of basal and top-dressing fertilizers are required and how much to apply per unit area.

Soil, nutrient and water management Soil, in its entirety, is the reservoir of nutrients and water and sustains life of soil organisms. Farmers should ensure soil loss is minimal and restorative practices are adopted. The Lands, Agriculture, Fisheries, Water and Rural Development ministry is promoting the Pfumvudza or Intwasa concept with the aim of climate proofing agriculture and increasing crop productivity for the small-holder farmer. The concept addresses fundamental and sustainable soil management aspects. These include:

Reduced tillage

The Pfumvudza or Intwasa concept involves minimum soil disturbance. Farmers use hoes to prepare planting basins that are 15cm wide, 15cm long and 15cm deep. The benefits of such basins is their ability to store water and minimise run-off losses. Minimum soil disturbance improves soil structure, thereby ensuring soil is not prone to water and wind erosion.

Mulch cover

The Pfumvudza or Intwasa concept stipulates that at least 30% of crop residue covers the soil surface. The cushioning effect of the mulch reduces soil loss by erosion, reduces run-off, aids water infiltration and reduces water loss by evaporation.

The 4R stewardship

The 4R stewardship forms the basis of efficient input utilization under the Pfumvudza or Intwasa concept. These are:

Right amount:- the proper application rate

Right source:- applying the proper type Right placement:- using the appropriate method of application

Right timing:- applying at the correct time for maximum benefit by the crop.

Lime, basal and top-dressing fertilizers are all directed to the planting basin in order to ensure efficient utilisation. The concept promotes precision farming in order to increase efficiency and effectiveness in resource allocation and utilisation.

Crop rotation

The Pfumvudza or Intwasa concept considers the benefits of crop rotation by ensuring legume crops such as soyabeans or oil seeds such as sunflower are in rotation with maize or traditional grains as dictated to by agro-ecological requirements. The legume crops fix atmospheric nitrogen. The use of rhizobium inoculants (bio-fertilizers) ensures that legumes harness enough of atmospheric nitrogen for maximum productivity. By using these cheap and environmentally friendly bio-fertilizers on legume crops, farming becomes a profitable business as there is a saving on inorganic nitrogen fertilizers.