David Bautze


Last Name

Bautze

First Name

David

ORCID

0000-0002-5498-3298

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2024 - 20262
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Publications 1 - 2 of 2
  • Closing the crop yield gap between organic and conventional farming systems in Kenya: Long-term trial research indicates agronomic viability
    Item type: Journal Article
    Bautze, David; Karanja, Edward; Musyoka, Martha; et al. (2024)
    Journal of Agriculture and Food Research
    The production gap between current and attainable yields is highest on Africa's smallholder farms, and some studies indicate that they might not benefit from the yield gains offered by conventional farming. Simultaneously, alternative farming systems like organic provide biodiversity and soil fertility advantages, but their ability to produce sufficient food is still under debate. Additionally, comparative data on the productivity of organic versus conventional in tropical regions are scarce or short-term. We investigated the crop productivity of organic and conventional farming systems using 15 years in two long-term systems comparison trials in Kenya. The trials were established in 2007 at two sites in the Central Highlands of Kenya. At each site, conventional and organic systems were compared at high input levels. The trial involved a three-year crop rotation cycle of maize, vegetables, legumes, and potatoes, repeated five times since its establishment. Management practices were kept similar in the first four rotations and revised in the fifth to improve systems representing best practices. Our results showed that while maize and baby corn had relatively low yield gaps (−13 to +12 %) between organic and conventional systems, cabbage, French beans, and potato had high yield gaps (−50 to −30 %). We attributed this to nutrient limitations and higher pest and disease damage. The yield gap could partially be closed by adopting best practices in the organic system, including system diversification and effective soil fertility, nutrient, and integrated pest management.
  • Organic farming with smallholder input rates cannot close the yield gap in Central Kenya
    Item type: Journal Article
    Bautze, David; Unternährer, Anouk; Matheri, Felix; et al. (2026)
    Organic Agriculture
    Compared to the rest of the world, crop production by smallholder farmers in sub-Saharan Africa shows sizeable yield gaps to the attainable yield. Organic farming is offered as one solution due to its positive impact on human and environmental health, but it is also questioned for its suitability to improve yield substantially. However, data on the comparative performance of organic systems under smallholder agriculture practices is scarce in the developing world. Our study addresses this critical aspect of crop production in sub-Saharan Africa. We investigated annual crop productivity under organic and conventional farming systems using smallholder nutrient application rates in two long-term systems comparison trials in the Central Highlands of Kenya. They involved a three-year crop rotation of maize, leafy vegetables, legumes, and potatoes, repeated five times since its establishment in 2007. Our results show that crop yields in conventional and organic farming systems were generally lower than achievable yields. The yield gap to the attainable yield was neither closed under the organic nor conventional systems. In addition, crop yield under organic was usually lower than in conventional systems. The low yields and yield gap resulted from the limited nutrients, high pest and disease pressure, and dependence on the declining and varying rainfall amounts. Our study highlights the need to improve input rates and, thus, the productivity of smallholder farmers as a key component in reducing poverty and increasing food security.
Publications 1 - 2 of 2