Evergreen agriculture is a form of agroforestry that integrates trees with crops, maintaining a green cover on the land throughout the year. It is one of the options to intensify agriculture to increase production and also provides environmental benefits including managing soil fertility and moisture.
The early win project, ‘Evidence for Scaling-up Evergreen Agriculture to Increase Productivity and Resilience of Maize mixed and Agro-pastoral Farming Systems in Tanzania and Malawi’ aimed to demonstrate that tree-based technologies that can be used to intensify maize-legume systems to increase yields and better manage soil nutrients and moisture through improvement of its organic matter and water retention capacity among other processes.
The study identified the constraints to agriculture as small farm sizes, drought, inadequate use of inputs (especially fertilizer and improved seeds), soil erosion, and soil nutrient depletion. As a result, crop yields in the field were below their potential and 60% of the respondents were not able to feed themselves all year round.
The project team used remote sensing techniques to quantify land use and land cover changes over the past 23 years. They found that while there was a 31% increase in land under agriculture, on the other hand, there was a 30% reduction of forest cover and a 2.1% increase in settlement.
“This demonstrates that the stagnant yield of maize (at 1 – 1.5 t/ha over the last 50 years in Tanzania and Malawi) has been sustained by the expansion of land under cultivation instead of intensification,” says Anthony Kimaro of World Agroforestry Centre (ICRAF), and one of the project researchers. “This is a common problem in sub-Saharan Africa and more research on sustainable intensification of farming systems are needed to minimize soil degradation in the region.”
The study also analyzed the biophysical characteristics of the soils and found that the soils were generally very poor. “The soils had extremely low values of major nutrients such as nitrogen, phosphorus, and soil carbon, which are not sufficient to optimize crop yield production. Any efforts to intensify agriculture would require replacement of nutrient and organic matter to improve soil health. And this is where evergreen agriculture can make a difference” Kimaro said.
“The benefits on evergreen agriculture include rehabilitation of degraded lands, supplying wood fuel, providing fodder for livestock and stabilizing crop yields against climate variability among others” he added.
The greatest value of trees to farmers in the dry areas was providing shade when working in the field and for firewood, the study established.
(Article by Catherine Njuguna)
The Africa RISING program comprises three linked research-for-development projects, funded by the USAID Feed the Future Initiative, and aiming to sustainably intensify mixed farming systems in West Africa (Southern Mali and Northern Ghana), the Ethiopian Highlands and East and Southern Africa (Tanzania, Zambia and Malawi).
To produce some short-term outputs and to support the longer term objectives of the projects, in 2012 Africa RISING funded several small, short-term projects in each of the regions. More information.