Zimbabwe’s reliability on winter ploughing in subsistence farming

By Calvin Manika

Owen Manunure drives his ox-driven plough following a pathway through a dense bush which leads to his fields behind a small hill in Maramba, Mashonaland East Province of Zimbabwe. Active human activities in the fields were last seen in April as people harvested their crops and they will return in early December as the rains returns commencing another rainy – agricultural season. Meanwhile, Manunure is tilling the fields without sowing seeds – they call it winter ploughing.

“I have been doing this since my formative years, I learnt it from my father and it proves to help in preparing the land. If you look, after the harvest, dried stalks are left in the fields. They are normally left for the livestock to survive during the winter and summer unto the fall as rains comes. For us we want them buried and prepare the land for the next season before the rains begin,” Manunure says.

When rains came in mid May, people took it as the beginning of the winter season which brings the cold spells and chilly winds. Manunure and others across Zimbabwe knows that it is an opportunity to till the land for winter ploughing as the activity preserves the moisture of the soils and make them intact and ready for the next season.

Most of the farmers who practice winter ploughing are the first ones to sow the seed in November when the first rains come and their crops usually succeed compared to those who sow without winter plough.

Deep winter ploughing is a technique which has been in practice for decades. It is now the standard recommendation by the government’s agriculture research and extension department. Adison Mandizvidza, and agronomist says the practise had a record of producing high yields if done properly.

“The technique involves ploughing to a 353 depth of 0.2 m soon after harvesting, and is favoured due to improvements in weed control. However, the majority of smallholder farmers plough to a depth of 0.1–0.12 m, resulting in the formation of a hardpan within the soil profile. The plough pan restricts root penetration and rainwater infiltration. Crops grown under shallow ploughing cannot withstand extended periods of soil moisture stress during mid-season dry spells,” Mandizvidza says.

Communal farming in Zimbabwe is largely rain-fed, and thus risky, due to high inter annual variability and the occurrences of dry-spells during the rainy season. Potential evapotranspiration exceeds rainfall for more than 6 months of the year. Rainfall is seasonal and highly variable both within space and time.

“Winter plough has many advantages to farming. Firstly, it clearly the land, imagine a cotton filed or maize itself. However, the benefits are much more than just cleaning the land. It assists in mixing the nutrients in the soils and keep the moisture we want for early crop farming,” notes Arnold Magare, a small-scale farmer.

According to Albert Makedenge, an agriculture expert at Vadhumeni, a Zimbabwe Agriculture Consultancy, winter ploughing ranges from tilling the fields before the hot September-October sun to the simple cutting down of small trees, bushes and stumps in and around the fields as various forms of land preparation, done more or less in winter – from March up until May, June and even beyond.

“Winter ploughing helps to reduce weeds. This is especially true for couch grass, whose long creeping roots are exposed to the sun by tilling. Which effectively reduces its incidence in the field. Weeds that are buried under the soil decay and enrich the field as manure. Another advantage of winter ploughing is that it destroys pests such as maize stalk borers in their pupal stage by exposing them to the sun. This will allow the crops to grow and develop in a pest-free environment for the best possible quality and quantity of the final yield,” Makedenge says.  

“Winter ploughing also helps to loosen up the soil and therefore making it more porous so that rainwater can seep in or infiltrate instead of flowing away as runoff without being accessible to roots of the plants or crops. A porous soil is much better as it allows free air circulation of important gases such as oxygen and nitrogen,” Makedenge adds.

Winter ploughing is one of the infield crop management practices practised in Zimbabwe. It is a tillage approach for crop establishment and weed management through to land forming practices such as tied ridges and land fallowing.

Research work in Southern Africa has concluded that the four most important constraints to rain-fed crop production are timeliness of planting, soil hydrological properties, weed control and labour.

Craig Irvine, an agronomist said it is important that after harvesting, farmers plough the land as this helps in conserve moisture which helps farmers when the first rains comes and also in weed control.

“Winter ploughing helps conserve moisture, decomposition of stalks and leaves that would have been left in the fields after harvesting. If the fields are not ploughed, weeds continue to grow and scatter seeds around the fields but through ploughing, the weeds are ploughed under and they also decompose and become manure,” Craig says.