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How to minimise moisture loss in farms and maximise crop yields

An FMD tractor at work. In the wake of climate change, the organisation says the current traditional methods of inverting the soil with several passes of a harrow thereafter, results in unnecessary moisture loss and soil degradation.

A UN body has called for need for farmers to embrace a tilling method that leads to minimum moisture loss.

In these seasons when the long rains in many parts of Kenya have been below average, the United Nations’ Climate Technology Centre and Network says there is need for farmers to minimise moisture loss in soil to counter the erratic rainfall caused by climate change.

One of the measures which can be taken to reduce soil moisture loss through heat stress is minimum tillage, says the organisation.

Minimum tillage leaves crop residue on the surface of the soil which helps reduce the evaporation and moisture loss caused by strong sunshine and wind.

Furthermore, the reduction of soil disturbance from the practice of minimum tillage also preserves existing moisture in the soil allowing crops to benefit from this during the dry periods.

Compared with the heavy cost of irrigation, minimum tillage involves moving from traditional three to four land prep activities to single passes with implements like a chisel plough, or subsoiler with a crumbler roller to prepare land prior to planting.

Promising boost in cereal output

Fergus Robley, the General Manager of FMD, the Massey Ferguson distributor for East Africa said: “The current traditional methods of inverting the soil with several passes of a harrow thereafter, results in unnecessary moisture loss and soil degradation.

The traditional method makes for a dry seedbed, with poor soil structure that results in crop yield limitations especially during a year with uncertain rainfall volume and distribution.”

In contrast preparing soil with a chisel plough, or deep subsoiler protects moisture and preserves surface trash whilst providing the necessary aeration through a shattering action to the soil under the surface.

This retention of valuable moisture is comparable to that of a forest floor with fallen leaves on the surface which provides similar preservation of moisture by acting as an umbrella for the soil.

“Preparing land for cultivation by minimum tillage using a chisel plough, or even better, a deep subsoiler to preserve moisture in the soil and allows for an economical one pass cost. This corrects the effects of regular use of disc ploughs and harrows over a period of years which causes hard pans, soil structure challenges and does not protect the soils for the future generations.”

The most promising boost in cereal output can be achieved by adopting minimum tillage (also known as conservation agriculture). This has been used in Brazil for years in areas with less rain than Laikipia to produce good harvests whilst preserving soil structure and moisture. This holds the prospect of expanding cultivating cereals to comparatively dry areas like Kitui, Makueni, Isiolo and Marsabit.

While minimum tillage cultivation is of great importance in dry rainfall areas it is very effective for most farmers anywhere in Kenya. By preserving soil moisture, farmers in areas like Kambi Ya Moto and Laikipia which were previously thought to be marginal for arable crops are achieving good results.

The equipment needed for minimum tillage consists of a good 4WD tractor, a subsoiler, a sprayer in sound working condition and a planter that is set up correctly to give the necessary plant population.

Calibration of sprayers and planters are key for successful best farming practices.

The best land preparation is achieved using a deep tine to penetrate the soil to a depth of 18 inches (45cm) to overcome the mechanical hard pan that usually occurs at eight to ten inches below the surface which results from years of disc ploughing and harrowing. The addition of using a crumbler roller on the back of the subsoiler provides a level and favourable seed bed for planting. 

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