Tanzania: Farmers conserve soil in hilly farms with minimum tillage and crop residues

| June 11, 2018

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The sky is clear and the sun is shining brightly on the steep, green slopes of Mount Meru in northern Tanzania. Farmer Felix Nassari is checking if last season’s maize stalks are sufficiently decomposed in her field so that she can prepare to plant carrots. She says, “Before planting, I leave the crop residues in the field.”

The 32-year-old mother and her six-year-old daughter live in Ndoombo village in the Meru highlands, about 40 kilometres from the city of Arusha. Here, farmers like Mrs. Nassari use conservation agriculture methods to reduce erosion and keep their soil healthy. This allows them to grow crops on the steep, erosion-prone slopes when water flows down the mountainside.

Mrs. Nassari grows and rotates maize, cabbage, potatoes, and carrots on her two hectares. After harvesting maize, she leaves the stalks in her field to decompose and add nutrients to the soil.

She also makes ridges and skillfully uses her hoe to dig shallow planting holes. This helps prevent the nutrient-rich soil from being washed away. She explains, “I make ridges [every 70 cm down the slope] to reduce the speed of water flow in the field, and I plant using a hand hoe. I avoid digging the holes too deep to prevent the formation of water channels.”

Sheilah Yusuf is an extension officer in the area. When she started working in the highlands 18 months ago, she was surprised to see how productive the farms were.

She says: “At my first visit to the farmers, I was very amazed how most farmers managed to grow crops on these steep-sloped highlands. For years, they have learned how to conserve their land.”

Mrs. Yusuf says farmers in the Meru highlands have used conservation agriculture methods for generations to get good yields despite the challenges of farming on a steep incline. These methods include making ridges, using minimum tillage, intercropping and crop rotation, and letting crop residues decompose on their fields.

Julius Naftari Nasari farms on three hectares of land in the same area. He intercrops maize and beans and, after harvesting his maize, he rotates with carrots or potatoes.

Mr. Nasari says he prefers to plant with a hoe so he doesn’t disturb the soil structure. He says a hoe is better than a tractor because it is difficult to ride tractors in hilly areas.

He adds, “The land is steep and in times of rain, you need your field to have good, compact soil; otherwise, nutrients will get washed down the hills.”

Mr. Nasari weeds by hand and uses manure as additional ways of protecting his soil.

But Mr. Nasari says these techniques are labour-intensive. He explains: “It takes a lot of time weeding by hand, planting using hand hoes, and it costs to add manure on top of vegetation to improve the soil. But this is the only way we can get a good harvest in this area.”

According to Mr. Nasari, the secret to producing a good harvest in the area is conserving the soil. He says buyers who come to purchase carrots in the Meru highlands are always astonished that farmers are able to grow crops on such steep slopes. The buyers are forced to leave their cars on the main road and carry the sacks of produce down the hill on their backs because the slope is too steep for cars to climb.

Despite the challenge of growing crops on steep hills, Mr. Nasari says that, for generations, local farmers have successfully produced many crops that are sold in surrounding towns such as Arusha.

Mrs. Nassari says that, by using techniques such as minimum tillage and allowing crop residues to decompose on the field, she has improved her soil.

Last season, Mrs. Nassari harvested 40 bags of carrots and 50 bags of Irish potatoes, each bag weighing 100 kilograms. She sells carrots for 500-700 shillings (US$0.22-0.31) per kilogram, and potatoes for 800 shillings (US$0.35) per kilogram.

She says that, through farming, she has helped her husband build a good brick house with a sheet metal roof. In addition, they now have a steady water supply in their home.

This work was created with the support of Canadian Foodgrains Bank as part of the project, “Conservation Agriculture for building resilience, a climate smart agriculture approach.” This work is funded by the Government of Canada, through Global Affairs Canada, www.international.gc.ca.

Photo: Felix Nassari