In this era of climate change, minimal tilling, crop rotation is key
Prof. David Mburu
| May 19th 2018 | 3 min read
The evidence of climate change is obvious, the unforgiving floods currently hitting farms, the extremely dry weather patterns.
Going forward, we need smart ways of farming to survive like conservation agriculture, a farming practice that ensures maintenance of good soil condition and fertility for sustainable agricultural production. Here are ways crop farmers can practise conservation agriculture:
-Crop residue management where farmers are discouraged from burning crop residue after harvest. Part of the residue is incorporated into the soil during land preparation to increase the soil organic matter. It is recommended that 30 per cent of crop residue is spread on the soil surface as mulch.
This will protect the soil against the impact of raindrops. There will also be reduced soil water loss through surface evaporation. The soil temperature is also regulated for good functioning of roots for optimum crop growth.
Surface mulch will control weed growth and this reduces production cost and hence high profit to the farmer. Surface mulch reduces velocity of surface runoff, control soil erosion and enhances rainwater infiltration into the soil profile.
-Improvement of soil physical characteristic which is reflected in the soil structure that would allow ease of water movement and minimise surface runoff accumulation.
One hindrance to water infiltration into the soil profile is development of hard pan a few centimetres below the soil surface. The hard pan can develop over time when ploughing is done at the same depth from year to year. This hard pan impedes water infiltration into the soil and causes fast accumulation of surface runoff during heavy rain.
The hard pan also reduces plant roots penetration into the soil profile and the result will be low crop yield. Conservation agriculture recommends occasional deep ploughing with appropriate implements like chisel plough, ripper, sub-soiler that would break the hard pan.
- Use of organic manure for nutrient supply to the growing plants is also recommended. Organic manure improves soil structure and the ease of releasing nutrients from the soil to the plants. Crop rotation is essential for soil fertility management and control of pests and diseases.
-Minimum tillage is also recommended especially in rainfall deficit areas. The practice advocates that conventional land preparation where the whole field is ploughed clean in every season is not necessary. Such practice exposes high soil moisture loss through surface evaporation. It is recommended that only the seed sowing row should be opened either with furrow opener or other implements mentioned above.
The weeds in the inter-row spaces are controlled by either slashing or herbicide application.
The residual moisture from the last season stored in the undisturbed inter-row spaces will benefit the planted crop. The crop residue in the inter-row spaces will act as soil cover and reduce soil moisture loss through surface evaporation. Such residue will finally decompose and add organic matter to the soil.
If the biomass production is too much for any particular crop, it is recommended to lay trash lines along the contour on sloping land to act as barrier of for runoff and deposition area for eroded soil from upper slope.
-Zero tillage is the practice where chemical weed control is done for land preparation before planting such that there is no soil disturbance apart from planting.
-Crops selection is also key. Crop types and varieties have to match the agroecology of the specific area of production in terms of rainfall amount, distribution and length of growing season and the soil type.
Finally, climate change has caused great variations in weather patterns. When there are prolonged droughts, conservation agriculture practices will enhance soil moisture conservation that will take crops to maturity and give assurance of harvest.
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