In 2007 two long-term trials were established in Kenya to contribute research-based evidence to the global debate on the productivity, economic viability and sustainability of different agricultural production systems. These trials compare conventional (Conv) and organic (Org) farming systems at high and low input levels at two locations, i.e. Chuka, with Humic Nitisols, high inherent soil fertility and rainfall, and Thika, with Rhodic Nitisols with low soil fertility and rainfall. The high input systems (High) represent commercial-scale, export-oriented production that uses the recommended amounts of fertilisers, pesticides and irrigation water to generate high yields, whilst the low input systems (Low) represent local smallholder practices, using relatively few fertilisers and pesticides and operating under rain-fed conditions. The conventional systems received synthetic fertilisers and organic manure, whilst the organic systems only received organic inputs. The trials so far have consisted of a 6-season, 3-year, crop rotation with maize (Zea mays L.) planted in the long rainy seasons (March-September), and vegetables in the short rainy seasons (October – February). Generally, there were no significant differences in the dry matter yields and nutrient uptake by maize, baby corn or beans between the conventional and organic systems at either site. Similar maize grain and baby corn yields were also obtained at Chuka. However, at Thika, maize grain yields in Org-High in 2007 (at conversion) were lower than the yields in Conv High, but the yields became similar in 2010 (after conversion). At the same site the yields of maize grain under sole cropping in Org-Low were 3.2 times lower than the yields in Conv-Low in 2007 and 1.7 times lower in 2010. When intercropped with beans the yields of the two systems were similar. In the first two years profits from Conv-High were 0.5–1.8 times and 0.2–2.4 times higher than in Org-High when selling the produce at local (Chuka and Thika) and regional markets (Nairobi), but thereafter the profit from the two was similar, even when organic produce was sold at regular market prices. From the fifth year onwards Org-High attracted a price premium of 20 to 50% and this made it 1.3 to 4.1 times more profitable than Conv-High when selling on local and regional markets (in Chuka, Thika and Nairobi). Compared to Conv-High, partial N and K balances at the two sites were positive and higher in Org-High, except for N at Chuka. Our findings demonstrate that Org-High is productive, economically viable, resource-conserving and can contribute to sustainable agriculture production in Kenya depending on regional conditions and the crops cultivated

Background: A long-term experiment at two trial sites in Kenya has been on-going since 2007 to assess the effect of organic and conventional farming systems on productivity, profitability and sustainability. During these trials the presence of significant numbers of termites (Isoptera) was observed. Termites are major soil macrofauna and within literature they are either depict as ‘pests’ or as important indicator for environmental sustainability. The extent by which termites may be managed to avoid crop damage, but improve sustainability of farming systems is worthwhile to understand. Therefore, a study on termites was added to the long-term experiments in Kenya. The objectives of the study were to quantify the effect of organic (Org) and conventional (Conv) farming systems at two input levels (low and high) on the abundance, incidence, diversity and foraging activities of termites.Results: The results showed higher termite abundance, incidence, activity and diversity in Org-High compared to Conv-High, Conv-Low and Org-Low. However, the termite presence in each system was also dependent on soil depth, trial site and cropping season. During the experiment, nine different termite genera were identified, that belong to three subfamilies: (i)Macrotermitinae(genera:Allodontotermes,Ancistrotermes,Macrotermes,Microtermes,OdontotermesandPseudocanthotermes), (ii)Termitinae(AmitermesandCubitermes) and (iii)Nasutitiermitinae(Trinervitermes).Conclusions: We hypothesize that the presence of termites within the different farming systems might be influenced by the types of input applied, the soil moisture content and the occurrence of natural enemies. Our findings further demonstrate that the organic high input system attracts termites, which are an important, and often beneficial, component of soil fauna. This further increases the potential of such systems in enhancing sustainable agricultural production in Kenya.

Termite-induced injuries to maize and baby corn were evaluated in on-going comparison experiments on organic and conventional farming systems at two trial sites in the Central Highlands of Kenya (Chuka and Thika). The farming systems were established in 2007 at two input levels: Low input level, representing subsistence farming (Conv-Low, Org-Low) and high input level, representing commercial farming (Conv-High, Org-High). Termite-induced injuries to maize and baby corn, such as tunneling the stem or lodging the whole plant were assessed over two cropping seasons. The lodging occurred exclusively at Thika. It first became apparent in the Org-Low system, with most of lodging occurring during the vegetative stage. Baby corn grown under high input systems showed increasing lodging from the late vegetative crop stage and peaked before the final harvest. Tunneling was recorded at both sites, but was generally below 5%, with no significant differences between the farming systems. Overall, the injury patterns caused by termites appear to be a function of the plant growth stage, termite colony activities, trial site, and the types and levels of fertilizer input. Thus, the management practice used in each farming system (organic or conventional) might have greater influence on crop injuries than the type of farming system itself or the termite abundance within each system.