Kenya: organic farming is productive and resource-conserving

Picture: FiBL long-term comparison study in Kenya. Data like the length of the maize cob are measured by the project team on the SysCom field trial at Chuka, Kenya. (© FiBL)

A long-term study in Kenya shows that maize yields and nutrient uptake in the organic farming systems are quite similar to conventional systems. Due to premium prices, organic systems are more profitable for farmers than conventional ones. The study was carried out by the Research Institute of Organic Agriculture (FiBL) in close cooperation with partners in Kenya.

Soil degradation and low crop productivity are main problems in sub-Saharan Africa, and Kenya is not an exception, explains FiBL. Kenya has a wide variety of soil types, from low to high fertility; however, most of these soils face problems such as acidity, nutrient depletion and poor drainage. Moreover, agronomic practices are often not the best, which accelerates soil nutrient mining and lowers crop productivity even more.

How to address soil degradation and increase productivity are the main questions that face Kenyan farmers.According to the FiBL project description a system comparison examined the challenges and potentials.  http://www.systems-comparison.fibl.org/de/scp-projekte-de/scp-kenya-de.html Organic agriculture is an option to revert environmental degradation, while achieving produce in a sustainable way.  However, long-term benefits or drawbacks of organic agriculture in Kenya have not yet been determined in a systematic manner.

Picture: On the plots at Thika (picture) - as well as in Chuka and the farm plots - soil samples are taken to analyse them at the laboratory (© FiBL).

Different areas with different conditions

The project area in Kenya is situated in the sub-humid highlands (Central Province) at approximately 1500m a.s.l. with an annual precipitation of 1500 – 2400 mm (Chuka) and 900 – 1100 mm (Thika), characterised by two rainy seasons. The project investigates two sites of different production potential, a production system based on a 3-year crop rotation with maize, beans, potatoes and vegetables. The conventional and organic treatments are run on two input levels each (low level represents subsistence farming; high level represents commercial growers).

    The Chuka site is located at 1’450m a.s.l., in the agroecological zone (UM 2) (according to FAO, 1996), also called main coffee zone. This zone is characterised by a medium to long first cropping season and a medium to short second season. Mean annual temperature is about 20°C. The mean annual rainfall varies between 1’500-2’400mm. Soils are classified as humic nitisols and they are of a volcanic origin with basic and ultra basic igneous rocks. Yield potential is high.

    The Thika site is located in the agroecological zone of the upper midlands (UM 3), named sunflower-maize zone. The site lies at 1’500m a.s.l. with an annual mean temperature of about 20°C. The mean annual rainfall ranges from 900 to 1’100mm. It has a short to medium and a short cropping season with the rains beginning in March and the short rains beginning mid-October. Soils are classified as dystric nitosol and are slightly susceptible to erosion. Yield potential is moderate.

For the participatory development of adapted technologies, Kangari, in Murang’a District, was selected. Kangari lies in a dairy/tea growing zone between 1'730 and 2'100 m a.s.l. Rainfall is distributed over two seasons, with 1'600-1'800mm per year. Temperatures vary between 12°C and 28°C. Besides their tea plantations, farmers have 2-3 livestock units (dairy cows, goats, chicken, rabbits) and on average 0.2 hectares of arable land, which is mainly used for vegetable production for both home consumption and market.

Picture: Preparation of compost like the smallholder farmer Josephine Ithiru from Chuka is producing, is an important component of organic agriculture (Quote Josephine Ithiru, Chuka, 4th February 2015: "Despite the absence of rain, I expect a better harvest this year than before because of organic agriculture. It improves soil fertility and moisture.") © FiBL

A recent publication in the journal “Agriculture Ecosystems and Environment” shows the results of maize-based conventional and organic farming systems over the first six years of two long-term field trials in Chuka and Thika in the central highlands of Kenya. Both farming systems were compared at input levels of commercial, export-oriented production (high) and at those of smallholder farmers (low).

Crop yields from organic systems were similar to those of high-input conventional systems

At each level, the farming systems were fertilized with the same amount of nitrogen and phosphorus, the conventional one with farmyard manure and mineral fertilizer, the organic one with compost, ash and rock phosphate. The researchers from FiBL and its Kenyan partners show that after a three-year conversion phase, crop yields from high-input organic systems were similar to those of high-input conventional systems in Chuka and Thika.

Despite higher production costs, the profitability of organic farming reached 1.3 to 4.1 times the profitability of conventional systems after the fifth year of conversion to organic due to premium prices. In the low-input systems at Thika, sole maize cropping produced three times higher maize yield in conventional compared to organic, but, when intercropped with beans, the maize yields were similar.

FiBL longterm comparison project in Kenya. Photo © FiBL

The study also revealed that nutrient balances on both sites were negative in the low-input systems as well as in the conventional high-input system. So these systems are mining for soil nutrients. The positive balance found in the organic high-input system was due to the common practice of leaving crop residues in the field. Therefore, the study suggests revisiting the fertilizer recommendations for small-scale farmers to secure yields and for export-oriented farmers to improve management practices to conserve resources.

The findings demonstrate that high-input organic farming is productive, economically viable, resource-conserving and can contribute to sustainable agricultural production in Kenya and the regions in sub-Saharan Africa that have environmental conditions similar to Chuka and Thika.

More information on the FiBL-website