Cacao agroforestry systems do not increase pest and disease incidence compared with monocultures under good cultural management practices

Pests and diseases threaten cacao production worldwide. Agroforestry systems are traditionally seen by farmers as one of the causes of increased pest and disease incidence, in contrast with full-sun monocultures. Cultural management practices - e.g. regular tree pruning, frequent pod harvest, regular removal of infested pods, weed management - have been reported to be crucial for pest and disease management. We performed two experiments for the purpose of assessing the effect of (i) different cacao production systems, and (ii) the frequency of harvest and removal of infested pods on the incidence of pests and diseases and on the cacao yield. The first experiment was performed in a long-term system comparison trial in Bolivia, where data on pest and disease incidence were recorded for three years in five production systems: two monocultures and two agroforestry system under organic and conventional farming, and one successional agroforestry system, i.e. a high tree density multi-strata system. Pest and disease management did not differ between systems and relied on cultural management practices. Overall, the incidence of pests and diseases did not differ between production systems, which indicated they were not the driver of yield differences between them. Across production systems, only 14% of the pods were affected by pests and diseases; 70% of these were affected by frosty pod rot. More than 80% of the pods infected by frosty pod rot were removed before the sporulation phase. In the second experiment, the effects of the frequency of harvest and removal of infected pods - every 15 days versus every 25 days - on pest and disease incidence and yield were tested in four farmers’ fields. Fortnightly harvest and diseased pod removal significantly decreased disease incidence and increased cacao yield, by 25% and 46% respectively. Our results show that cacao agroforestry systems do not increase pest and disease incidence compared with monocultures when good cultural management practices are implemented, which, in turn, can increase the productivity of the cacao plantations

ORGANIC FARMING ENHANCES THE RECOVERY OF ANCIENT CROPS AND SEGETAL WEEDS IN CATALONIA (NE OF SPAIN)

The Area of Natural Interest of Gallecs (ANIG) is one of the largest areas of arable land managed organically in Catalonia. In 2005 a project was launched to convert fields to organic farming and recuperate traditional crop varieties. The aim of this work is to analyse the changes in diversity of the weed flora, including segetal and rare species, and of crops in 20 fields (ca. 50 ha) after the conversion to organic farming during 5 cropping periods (2005-2010). Number of cultivated crops has increased from 1 to 17 including ancient and local varieties of cereal and legumes. Weed biodiversity increased by a 50% in five years at field and regional scale. Crop rotations and sowing organic seeds from other farmers can contribute to the increase and the conservation of the weed diversity in the arable agroecosystems, including segetal species which are currently rare or even have disappeared from most of the conventional arable fields

Beikrautsamenvorrat im Vergleich reduzierter und konventioneller Bodenbearbeitung unter Biobedingungen

Armengot L, Berner A, Blanco-Moreno J, Mäder P & Sans FX (2014) Long-term feasibility of reduced tillage in organic farming. Agron Sustain Dev 35(1): 339-346. Cooper J et al. (2016) Shallow non-inversion tillage in organic farming maintains crop yields and increases soil C stocks: a meta-analysis. Agron Sustain Dev 36: 1-20. Gruber S & Claupein W (2009) Effect of tillage intensity on weed infestation in organic farming. Soil and Tillage Research 105(1): 104-111. Montgomery DR (2007) Dirt: The Erosion of Civilizations. University of California Press, California. Moonen AC & Barberi P (2004) Size and composition of the weed seedbank after 7 years of different cover-crop-maize management systems. Weed Research 44(3): 163-177

Systems and Managements Related Differences in Phenology of 12 Cocoa (Theobroma cacao L.) Cultivars

Cocoa production systems can vary from a mono-cropping (MC) full sun plantation to a highly diversified successional agroforestry (SAFS). Mono-cropping is still the most common one but recently agroforestry (AF) systems have raised more interest because of their expected long term resilience. Nevertheless, information about the influence of cropping systems and management methods such as organic versus conventional in cocoa production and phenology in South America is missing. This study is based on the SysCom program’s framework located in Alto Beni (Bolivia), where three cropping system (MC, AF and SAFS) are compared. Additionally, MC and AF systems are conventionally and organically managed. A total of 12 cultivars including local clones, foreign clones (from the Imperial College Selections and Trinidad Selections) and hybrids are planted in each system. The aim of the present study is to identify differences between systems, management methods, cultivars and the respective interactions on cocoa phenology. Data on flushing and number of flowers, small, medium and big fruits and cherelles are being recorded every 15 days from March 2015. The trial was designed according to a split plot design with four replicates. Principal component analysis (PCA) and cluster analysis were performed on the cultivar level. Additionally, the collected data will be statistically analysed with a generalised mixed model (Poisson distribution) to test the effect of the different cultivars, systems and their interactions on the phenological traits. Preliminary results of the PCA and cluster analysis do not show a clear grouping pattern between the three types of genotypes analysed. This suggests that there are differences between cultivars but they are not consistent within the three groups. Preliminary descriptive results of the collected traits show differences between single cultivars and systems, but not between managements (organic vs. conventional). Some of the traits seem to be more system dependent than others. For instance, the number of cherelles seems to be higher in the SAFS than in the other systems. Additionally, interactions between systems and cultivars are expected to be present. This would be positive in terms of potentiality for selection of cultivars adapted to each different system

WEED FLORA IN A LONG-TERM REDUCED TILLAGE TRIAL, “TILMAN-ORG session”

Reduced tillage may improve the environmental and economic performance of organic farming. Reducing the intensity of soil tillage decreases the energy consumption and the emission of carbon dioxide, and could increase carbon sequestration (Holland 2004). Reduced tillage also may improve water retention and reduce soil erosion (Berner et al 2008). One of the main drawbacks of the reduced tillage practices is the potential increase of weed infestation and changes in weed species composition, sometimes to the benefit of species which are more difficult to control, such as perennial and grass species (Peigné et al 2007; Teasdale et al 2007; Sans et al 2011). Organic farmers commonly keep weeds under control by ploughing and by post-emergence mechanical methods, and by indirect means such as appropriate crop rotation including e.g. gras-clover. For this reason, weed management under reduced tillage conditions is expected to be more challenging in organics systems. In this study, we present the results on weed abundance and community composition in a nine-year old long-term experiment under conventional and reduced tillage

The role of shade tree pruning in cocoa agroforestry systems: agronomic and economic benefits

Cocoa-based agroforests are promoted to replace monocultures for the provision of ecosystem services. However, shade tree pruning, an important tool to sustain cocoa yields, is not commonly implemented. This study investigates the effect of pruning on both agronomic and economic performance. In Bolivia, four famers’ sites were divided in half, and shade trees pruned in one of the two plots. Pruning resulted in a significant increase in cocoa yield, from an average of 430 to 710 kg ha−1 by boosting flowering and pod production, but not reducing the proportion of damaged pods, and of those lost to cherelle wilt. Additionally, scenario calculations using international and organic premium cocoa prices were conducted to evaluate the economic feasibility of pruning. The minimum, mean and maximum yield of 22 local cocoa-based agroforestry farms were used as reference for 25, 50 and 75% yield increase scenarios. Offsetting the pruning costs highly depended on the initial yield levels. Using the minimum yield, all scenarios led to a lower net income compared with no pruning. For the mean yield level, the net income was equal to that obtained without pruning when the yield increase was above 51%. At the maximum yield level, all increase scenarios resulted in a higher net income. Our results prove the importance of pruning agroforestry trees to increase cocoa yields. However, with current farm-gate prices for cocoa, farmers alone cannot cover the extra management costs. The cocoa sector should discuss different strategies to support pruning for a broader adoption of agroforests

Comparison of Methods to Assess Dry Bean Yield of Different Cocoa Cultivars

To estimate the cocoa dry bean weight from the fresh weight a standard dry bean factor (DBF) ranging from 32% to 40% is usually applied. This factor, i.e. the relation between the dry bean weight (fermented and dried) and the fresh weight at pod opening, is used by cooperatives and factories that buy the fresh beans of the farmers. However, this factor is subjected to seasonal fluctuations and can be highly influenced by rainfall. Therefore, for instance, higher values are expected during the dry season compared with the rainy season. The objective of this study was to evaluate the accuracy of the use of a standard fix DBF value compared with the use of actual DBF values periodically collected over the season for assessing the performance of 12 cocoa cultivars (clones and hybrids). We hypothesised that using the same DBF for different cultivars that may have the production peak at different times of the season can lead to over- or underestimations of the yield performance. The study was performed in a long-term cocoa trial in Alto Beni, Bolivia, which comprises full-sun monocultures, agroforestry and successional agroforestry productions systems. In 2014, for each harvest date, cultivar and production system, a subsample of the fresh beans was collected, put in a mesh bag and weighted. After the fermentation and drying process, the subsamples were weighted again and the DBF was then calculated at 8% water content of the beans. The total performance of each cultivar at the end of the harvest season was estimated using the actual DBF for each cultivar, system and harvest date, and the results were compared with the performance estimated using the DBF values averaged across systems, harvest dates and varieties and also with the fixed DBF of 35%. The results only showed minor differences in the overall performance of each cultivar when comparing the different methods used. However, for all the cultivars, using the 35% fix value gave the poorest estimation compared with any of the other DBF tested, mainly due to underestimation of the performance of the early maturing cultivars

Food-energy-water nexus of different cacao production systems from a LCA approach

[EN] life cycle assessment (LCA), of four young cacao production systems: two full-sun monocultures and two agroforestry systems under conventional and organic management. Land footprint (LF) for food production, non-renewable cumulative energy demand (NR CED) for energy, total water footprint (TWF) for water, and three efficiency indicators for the FEWn were all analysed. In addition, ten LCA impact categories were evaluated in relation to two functional units (kilograms of cacao output and kilograms of total crop output, i.e., cacao þ other crops). The integrated analysis of the FEWn and the LCA framework reveals how agroforestry systems and organic management report better environmental performances for almost all indicators and impact categories considered, except for the TWF. However, given that the systems analysed have no irrigation, between 96.3% and 99.8% of the TWF corresponds to green water, i.e., soil moisture from precipitation. Green water has lower environmental impacts and opportunity costs than the water used to manufacture inputs (WFinput). Accordingly, when the efficiency of the nexus is measured in relation to the WFinput, organically managed systems produce more food/energy per unit of water used. Our results show how production diversification and organic and cultural management practices can improve energy efficiency and reduce the use of water associated with the inputs and, consequently, improve the nexus, as well as the rest of the environmental impacts analysed. The design of agricultural policies focused on sustainability should strongly favour the establishment of agroforestry systems, particularly those that are organically managed.S

Efecto del laboreo mínimo (chisel), la fertilización y los abonos verdes sobre la flora arvense y los rendimientos en una rotación de cultivos de cereales y leguminosas ecológicos

Effects of reduced tillage, fertilization and green manures on the weeds and crop yields in a cereal-legume crop rotation under organic farming. On 2011, we established a long-term experiment to evaluate the effects of reduced tillage (chisel vs mouldboard plough), fertilization with semicomposted manure and sowing of green manures before spring crops, on the crop yields and weed abundance in a 5-year rotation (spelt, chickpea, wheat, lentil and spelt). After five years, there was not noticeable increment in weed abundance or richness. Reduced tillage caused a significant increase of weeds compared with mouldboard plough, but it this increase did not cause significant yield loss in cereal crops compared with mouldboard plough. Green manures exerted a strong weed suppression, although this effect did not persist on the subsequent (legume) crop. Entre 2011 y 2016 se realizó un experimento para evaluar el efecto del laboreo mínimo (chisel) respecto a arado de vertedera, de la fertilización con estiércol y de la siembra de abonos verdes antes de los cultivos de primavera, sobre los rendimientos del cultivo y la abundancia de las malas hierbas, en una rotación de 5 años (espelta, garbanzo, trigo, lenteja y espelta). El laboreo mínimo provocó un aumento significativo de las arvenses pero sin conllevar pérdidas significativas en los rendimientos de los cereales respecto a los rendimientos con el arado de vertedera. El abono verde ejerció un fuerte control sobre las malas hierbas, aunque este efecto no persistió durante el cultivo de la leguminosa inmediatamente posterior

Sustainability of food security in different cacao production systems: A land, labour, energy and food quality nexus approach

The present work analyses the sustainability of food security in cacao monocultures and agroforestry systems under organic and conventional management. Using a novel approach, we developed indicators to assess crucial dimensions of food security, including land and labour productivity, the nutritional quality of food, and their nexus with energy efficiency and consumption. Our ten-year data showed that monocultures, especially conventional ones, are more productive (in terms of land and labour) when only the main crop (cacao) is considered and energy consumption is not assessed. When all the crops produced and the demand for non-renewable energy are included, agroforestry systems are more productive (kg, kcal, proteins and fats and nutritional quality index) and more energy efficient than monocultures according to all the indicators analysed. Therefore, encouraging policies that take into consideration the positive externalities of agroforestry and organic management is crucial for the sustainability of food systems