Christian Andres

ETH Zurich | ETH Zürich · Institute of Agricultural Sciences

In three decades, West Africa has become the leader in "bulk" cocoa (Theobroma cacao L, Malvaceae), as the region saw its production grow from 1.37 million tons to 3.47 million tons per year, making up today over 70% of the world production (Fontaine and Huetz-Adams, 2020). Illustrating this development is the contribution of the cocoa industry to...

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we...

Research in environmental science relies heavily on global climatic grids derived from estimates of air temperature at around 2 meter above ground1-3. These climatic grids however fail to reflect conditions near and below the soil surface, where critical ecosystem functions such as soil carbon storage are controlled and most biodiversity resides4-8...

Scientific knowledge, societal debates, and industry commitments around sustainable cocoa are increasing. Cocoa agroforestry systems are supposed to improve the sustainability of cocoa production. However, their combined agronomic, ecological, and socio-economic performance compared to monocultures is still largely unknown. Here we present a meta-a...

There is a need to investigate and identify locally available organic substrates with acidifying potential, which can be used as an additive in rock phosphate (RP)-organic material composting mixtures. This paper reviews attempts to increase P availability in the context of smallholder, low-input and organic farming, and presents a case study from...

The cocoa swollen shoot virus disease is a major factor limiting cocoa (Theobroma cacao L.) productivity for West African farmers. The only treatment against this disease is to cut infected trees and replant with disease-free planting material. Research has recommended the prevention measures: (i) cordon sanitaire (leaving 10-m-wide cocoa-free zone...

Shade trees in agroforestry systems protect the understory cocoa from climate extremes. Shade tree pruning manages microclimatic conditions in favor of cocoa production while tree diversity is maintained. Adaptation of pruning has to consider seasonal changes in temperature and precipitation to protect the understory cocoa. Structural characteristi...

This dataset contains the canopy openness and light, throughfall, temperature and relative humidity of cocoa monocultures and agroforestry systems within a long-term trial in Alto Beni, Bolivia. The dataset has be described in the Article "Shade trees and tree pruning alter throughfall and microclimate in cocoa (Theobroma cacao L.) production syste...

Currently, the only effective treatment for cocoa (Theobroma cacao L.) infected with the cocoa swollen shoot virus disease (CSSVD) is to cut and replant infected trees. Hence, the development of preventive control measures and strategies to mitigate the severity of the disease are of utmost importance. While past research has mainly focused on resi...

Cacao production systems are characterized by the occurrence of associated trees, the total stem density, the number of species, and the ecosystem services they provide. In a long term field trial in Alto Beni, Bolivia, comparing five cacao production systems, we monitored microclimatic differences at 1 m height between a cacao monoculture and two...

Organic food and farming systems have a great untapped potential to provide the world with healthy, high-quality food that is produced and distributed in an ecologically sound and fair way, but numerous production challenges and barriers slow the adoption of organic practices. Innovations addressing these challenges are not being developed sufficie...

Cocoa Swollen Shoot Virus Disease (CSSVD) is one of the major factors limiting cocoa (Theobroma cacao L.) productivity in West Africa. The only cure for CSSVD is to cut out visibly infected trees and the official eradication campaign in Ghana has cut out more than 200 million trees since 1946. 80 years of research on preventive control measures hav...

The global demand for cacao has recently increased. To meet this demand, the cultivated area has been expanded in tropical forest areas and production has intensified by replacing traditional agroforestry systems with monocultures. This has led to a loss of biodiversity in cacao-growing areas. More sustainable production systems such as agroforestr...

Cadmium (Cd) uptake by cocoa has recently attracted attention, after the European Union (EU) decided to establish values for tolerable Cd concentrations in cocoa products. Bean Cd concentrations from some cocoa provenances, especially from Latin America, were found to exceed these values. Cadmium uptake by cocoa is expected not only to depend on a...

Yams (Dioscorea spp.) are widely grown throughout the tropics. Three yam species constitute the staple food for more than 60 million people in five West African coastal countries, where more than 90% of the world's production takes place. Here we give a general introduction to yams, including their origin and geographic distribution as well as diff...

SUMMARY Cocoa ( Theobroma cacao L.) is produced in systems of varying complexity ranging from monoculture with temporary shade to highly diverse agroforests. Producers have to weigh high cocoa yields in the short to medium term in monocultures against higher total system yields in the short term and sustainable production systems in the long term i...

Rapid population growth, increasingly complex economies and novel industrial uses of agricultural products call for further intensification of agriculture, particularly in the tropics. How to achieve sustainable intensification of food production systems in tropical regions that are challenged by ongoing climate change, loss of natural resources an...

The growing demand for cocoa beans and products worldwide has been met by expanding the area under cocoa production while productivity per hectare has stagnated at a low level of around 450 kg/ha per year in the last decade. Throughout the tropics cocoa has increasingly been cultivated in full-sun monocultures in order to maximize short-term produc...

Cocoa cropping systems vary from full-sun monocrops to highly diversified agroforestry systems, which combine the cocoa production with by-crop such as bananas or plantains and trees with different functions. Additionally, these systems can be organically or conventionally managed. Although labour demand is one of the main activities contributing t...

A standard dry bean factor (DBF), ranging from 32 % to 40 % is usually applied for estimating the dry bean yield from the fresh yield. However, the DBF might be subjected to seasonal fluctuations, mainly due to rainfalls, and also might differ between cultivars. In our study we detected fluctuations over time of the real DBF. Nevertheless, the minor...

The debate on the relative benefits of conventional and organic farming systems has in recent time gained significant interest. So far, global agricultural development has focused on increased productivity rather than on a holistic natural resource management for food security. Thus, developing more sustainable farming practices on a large scale is...

This study compares aboveground and belowground carbon stocks and tree diversity in different cocoa cultivation systems in Bolivia: monoculture, simple agroforestry, and successional agroforestry, as well as fallow as a control. Since diversified, agroforestry-based cultivation systems are often considered important for sustainable development, we...