Word from the Market with Social Shava
THE Meteorological Services Department has predicted erratic and low rainfall patterns this year because of El Nino conditions that are expected to affect Southern Africa because of climate change.
The reality of climate change is upon us, and its consequences can curtail economic growth by reducing food production if farmers do not adopt mitigatory measures. Farmers are urged to be prepared for the effects of climate change, which are basically prolonged dry spells, too much heat stress on crops and erratic rainfall that also endangers the health of livestock due to poor pasture regrowth.
Farmers should always adhere to good agronomic practices that minimise greenhouse gas emissions and optimise yields. Normal to below-normal rainfall and too much heat predicted by the Meteorological Services Department require farmers to adopt strategies that save crops and livestock from drought.
This article pinpoints six strategies farmers should rely on to counter the expected effects of heat and drought conditions expected this season.
- Choose drought-tolerant varieties: Farmers should choose drought-tolerant varieties that have a track record of performing well in their agro-ecological region.
In regions 1, 2 and 3, farmers can grow maize, but the variety selected must have a comprehensive trait package of drought tolerance and high-yield potential. In the seven-series category, farmers can use a variety that takes between 138 and 145 days to mature. And it should mature earlier than any other seven-series varieties, yet have a yield potential of plus 16 tonnes per hectare.
The variety has excellent drought tolerance and has shown stable yields across seasons and regions. Selection must be informed by the performance of the variety, mainly focusing on hydro-efficiency and reliability under sub-optimal conditions.
In high-potential areas, early-maturity hybrids are important for late planting as they have a shorter growing period and give a competitive yield of more than 11 tonnes per hectare. It goes without saying that farmers in regions 1, 2 and 3 should have at least three different varieties in different maturity groups.
However, the seven series should be planted first, followed by the medium maturity hybrid, then lastly early medium hybrids. In regions 4 and 5, small grains and very early to ultra-early maize hybrids should be anchoring the cropping programme as the heat and drought conditions often experienced in these areas call for genetics with excellent drought tolerance and early maturity.
Very early maturity maize hybrids can do well under drought conditions due to their superior drought tolerance and shorter growing cycle. Emerging crops such as sunflowers are highly drought-tolerant and can be grown in marginal areas and offer economic benefits to farmers and the nation at large as they are a major source of cooking oil and stock feeds.
Additionally, sunflower helps in controlling problematic weeds in resource-poor communal lands, for instance, Striga, by stimulating it to germinate and killing it by not supporting growth of the weed.
Early planting: Planting with the first effective rains is the key enabler to productivity, both under irrigation and under dry-land farming. Farmers should, therefore, prepare their land ahead of time so that planting operations are done on time. Once the farmer fails to plant on time, there is a high probability of crop failure as the growing season is shortened, heat units for the crops are reduced and the crop is most likely to face high pressure of pest and disease infestation. Rainfall received without crops having been planted goes to waste as it may not contribute to productivity given that, afterwards, moisture is lost from the soil through evaporation.
Avoid too much soil disturbance: Minimal soil disturbance helps to maintain the soil structure and maximise water infiltration into the soil. Too much soil disturbance through deep ploughing and hoe weeding can speed up moisture loss due to evapotranspiration.
Furthermore, minimising soil disturbance reduces production costs and tear and wear of implements.
Soil disturbance using heavy equipment may lead to soil compaction that reduces water infiltration, leading to too much runoff. Weeding using mechanical methods may cut crown roots, which are important for drawing water and nutrients from the soil. It may also cause injuries to plant stems, which predispose the plants to boil smut as pathogens enter the crop system through injury sites. Farmers must use implements that minimally disturb the soil during planting and herbicides to control weeds to make sure the soil structure is not tempered with.
Water harvesting: Every drop of water counts, so farmers should use water harvesting techniques. They should use the precious liquid to their advantage during peak periods of droughts. Water can be collected from building roofs during rainfall and directed to storage tanks or other water bodies, where it can be kept for future use.
Alternatively, farmers may promote drainage of water into the fields to create a reliable moisture bank through use of tied ridges or potholing. Potholing and tied ridges help to make sure there is minimum runoff in the fields and plenty of water goes into the soil profile, thereby creating a reliable moisture bank for the benefit of crops during dry spells.
Crop diversification: Farmers should plant a range of crops to spread the risk of yield loss due to drought conditions. These should include cereals, legumes and cash crops. Legumes should be selected as a rotational fit for other crops, as they enrich the soil with nitrogen and organic matter for the following crop in a rotational sequence. Farmers who are into maize production should plant at least three varieties with different days to maturity. Planting must be staggered in a way that allows those varieties to tassel at different times. They should select varieties with drought-escape agronomic traits to circumvent losses often caused by water stress in maize production.
Pastures should also be improved to provide livestock with quality feeds that enable them to survive the impending drought conditions.
Planting Brachiaria spp in pastures is good for livestock.
Once planted, it regrows every rainy season for up to 20 years and will provide feed for your animals throughout the year. It is drought-resistant and grows well even in less fertile soils.
Deficit irrigation: This is an emerging irrigation strategy that saves water and maximises water use efficiency by only applying irrigation water during drought-sensitive growth stages of a crop and limiting water supply during the vegetative stages and late ripening stage.
Plants are exposed to water stress to a certain degree that does not reduce the yield of the crops and at that time, the variety’s drought tolerance is of utmost importance to enhance the ability to cushion the farmer from yield loss.
With deficit irrigation, total water supply is, therefore, not proportional to irrigation requirements throughout the crop cycle, and it maximises irrigation water productivity. This greatly saves irrigation water and reduces the leaching effects of nutrients from the root zone.
In conclusion, farmers must take a holistic approach to farming business that mitigates the effects of climate change, and adopt farming strategies that reduce greenhouse gas emission and ensure sustainable production.
Social Shava is an agronomist by profession. Word from the Market is a column produced by the Agricultural Marketing Authority to promote market-driven production. Feedback: [email protected] or WhatsApp/Call +263781706212.
