Browsing by Autor "Joachim Milz"

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Cacao agroforestry systems have higher return on labor compared to full-sun monocultures
(Springer Science+Business Media, 2016) Laura Armengot; Pietro Barbieri; Christian Andrès; Joachim Milz; Monika Schneider
Competitive yields in organic and agroforestry cacao cropping systems: results from 15 years of a long-term systems comparison trial in Bolivia
(Springer Science+Business Media, 2025) Johanna Rüegg; Stéphane Saj; Ulf Schneidewind; Joachim Milz; Monika Schneider; Laura Armengot
Abstract Cacao production is facing challenges of low productivity due to low soil fertility and climate change. Agroforestry and organic farming are potential sustainable and climate-resilient alternatives, but they are often associated with lower yields compared to monocultures and conventional farming. Despite their potential, empirical data on the long-term productivity of cacao cultivated in complex agroforestry systems and under organic management remains limited. Expanding this evidence base is essential to inform the development of agricultural practices and policies that advance environmental sustainability and food security. To fill this gap, we present 15 years (2008–2022) of data on cacao production and associated crops of a unique long-term trial comparing five cacao cropping systems in Bolivia: organically and conventionally managed monocultures, diverse agroforestry systems under organic and conventional management, and successional agroforestry systems without external inputs. We collected data on yields along with detailed information on the design and agronomic management from the beginning of the trial. All systems achieved competitive cacao yields in the mature phase. Organic and conventional systems had similar cacao yields, while agroforestry systems reached 56% of monoculture yields. Total system yields of the agroforestry systems were up to 6.9 times higher than monocultures. In the successional agroforestry, 22 crops were harvested, with short life cycle crops contributing to one-third of total production. This study shows that staple food crops and fruit trees as well as high-value crops (coffee, ginger, curcuma) can be successfully combined with cacao, and that agroforestry designs can be adapted over time by adding or eliminating crops to meet new goals or market opportunities. Extensive research has highlighted the positive contributions of agroforestry and organic farming to the delivery of ecosystem services. This study provides empirical evidence that it is possible to design and implement systems that reconcile environmental sustainability with productive performance.
Effects of pruning on flowering and yields of Cacao Nacional Boliviano
(Springer Science+Business Media, 2025) Chigusa Keller; Johanna Rüegg; Consuelo Campos Campos; Edwin Ontiveros Loza; Chloé Durot; Joachim Milz; Monika Schneider; Stéphane Saj
Abstract Cacao Nacional Boliviano (CNB), the native cacao germplasm group in the Bolivian Amazon region, possesses distinct morphological, genetic, phenological and organoleptic characteristics. It is highly sought after in the global fine-flavour chocolate market, and has importance for conservation of cacao genetic diversity. However, CNB cultivation is minor and yield levels low. Aiming to develop profitable CNB cultivation practices adapted to its distinct phenology and genetic basis, we compared parameters on CNB flowering, yields, biomass and harvesting effort in three agricultural systems with and without pruning and varying management intensity: agroforestry with pruning (AF), underplanted secondary forest with (SFwP), and without pruning (SFnP). Repeated measures linear mixed models using Restricted Maximum Likelihood were applied for statistical analysis. While AF and SFnP yielded 127.6 ± 21.4 kg ha −1 and 212.4 ± 22.2 kg ha −1 on average, reaching > 300 kg ha −1 after 11 and 9 years, respectively, SFwP yields remained significantly lower than SFnP, with an average of 58.0 ± 9.5 kg ha −1 and maximum yield of 122.6 ± 36.5 kg ha −1 . This study demonstrates there may be a trade-off between pruning intensity and yield in AF and SFwP, as observed on young CNB trees’ yield developments and yield increases during two years without pruning in mature trees. Based on preliminary results and CNB-specific phenology, we suggest a moderate pruning intervention early in July (allowing recovery time before start of flowering season in August), along with the need for validation of our findings and further investigation into management practices tailored to CNB.
El cultivo de la hoja de coca en sistemas agroforestales dinámicos en los Yungas de La Paz
(ETH Zurich, 2018) Johanna Jacobi; Luis Lohse; Joachim Milz
La coca es uno de los cultivos más antiguos en los Yungas de La Paz. Hoy en día, en su mayoría se planta en monocultivos y muchas veces en laderas inestables. El monocultivo de coca degrada los suelos, causa deslizamientos de terrenos, pérdida de biodiversidad y se desarrolla con el uso de agroquímicos potencialmente dañinos para la salud humana, los suelos y los cuerpos de agua. Sin embargo, en los Yungas persiste también un conocimiento ancestral sobre formas más sustentables de producción de coca con cultivos diversificados con árboles, arbustos y hierbas de diferentes usos. En este estudio se identificaron iniciativas y experiencias de recuperación de conocimientos ancestrales del cultivo sostenible de la coca, que integran técnicas de la agroforestería dinámica. La creciente demanda para coca orgánica puede ser una oportunidad para incentivar cultivos más sustentables y adaptados al cambio climático, que al mismo tiempo contribuyan a la seguridad alimentaria de las familias. Actualmente, el cultivo de coca con certificación orgánica en agroforestería dinámica ya representa una vía para más de 300 familias cocaleras en las Yungas de La Paz, y en miras de la degradación de suelos y la alta demanda de nuevas tierras para cultivar coca que está amenazando las áreas protegidas, es un potencial económico y ecológico para las más de 13 500 familias cocaleras de los Yungas paceños. Sin embargo, el cultivo de la coca en agroforestales dinámicos necesita apoyo técnico e institucional en el manejo de los sistemas agroforestales, en la investigación y en la comercialización tanto de la coca agroecológica como otros productos agroforestales.
Locally-selected cacao clones for improved yield: a case study in different production systems in a long-term trial
(Frontiers Media, 2023) Laura Armengot; Marco Picucci; Joachim Milz; Jon Kehlet Hansen; Monika Schneider
Ageing plantations, poor genetic material, soil degradation, pests and diseases are, among other factors, limiting cacao production. To meet the increasing demand for cacao in the absence of productivity gains, forests are cleared and the use of external inputs is generalised, with severe negative impacts on biodiversity and GHG emissions. The use of improved plant genetic material should support a sustainable increase of production. In this study, we evaluate and compare the yield performance of four locally-selected clones with those of four widely-used international clones in South America and four full-sib families (crosses of the same international clones). The research was conducted in a long-term trial in Bolivia with different production systems, including monocultures and agroforestry systems under organic and conventional farming and a successional agroforestry system without external inputs. Their cacao yields and the factors determining productivity (pod index, flowering intensity, pod load, pod losses, aboveground biomass, harvesting period) were assessed during 5 years. The cacao trees grown in the two monocultures had higher yields than those in the agroforestry systems. This was the result of higher aboveground biomass, flowering intensity and pod load, and similar pod losses due to cherelle wilt and fungal diseases in the former when compared with the latter. No differences between conventional and organic management were observed. We did not identify any genotypes performing better in a specific production system. On average, the local clones had twofold and five times higher yields than the international ones and the full-sib families, respectively. This was related to their higher total pod load, bigger pods and higher yield efficiency, i.e., higher yield per unit of tree biomass. However, the local clones had less flowering intensity, more cherelle wilt and similar losses due to fungal diseases to those of the international clones. This study clearly shows the need to invest in selection and breeding programmes using locally-selected genetic material to increase cacao production and support renovation/rehabilitation plans. Breeding genetic material that is adapted to low light intensities is crucial to close the yield gap between monocultures and agroforestry systems, and to further promote the adoption of the latter.