Despite tremendous efforts made in agricultural sectors in sub-Saharan Africa in the last two decades, fruits production and consumption to reduce malnutrition and chronic diseases remain low and have received less attention. Moreover, our knowledge of the current production situation and options for improvement are still limited. In this study, we investigated citrus farming systems and production bottlenecks to identify leverage points for intensification of smallholder citrus farming systems in Benin. We provided a typology of citrus orchards based on 17 quantitative and qualitative variables using Factor Analysis of Mixed Data combined with Hierarchical Cluster Analysis. The typology revealed four categories of citrus farms based on biophysical resources, socioeconomic resources and system management practices. Categories 1 and 2 included farms characterised by less diversified cropping systems with non-recommended management practices. Orchard categories 3 and 4 included farms with high varietal diversity and improved management practices. However, farmers of category 4 neglected staking and digging practices. The inadequate farming practices explained some of the production bottlenecks, which were orchard-type dependent. We discussed the implications of our findings and suggested a number of policy and strategic decisions as well as research and development actions for improving citrus production in Benin.

Quality of animal manure as a nutrient source for crops and as a soil conditioner depends on how fast the organic matter is decomposed, releasing plant nutrients or building up the soil organic matter (SOM) pool. This turnover process is governed by manure composition, soil temperature, soil moisture and secondary metabolites in the manure such as tannins. To investigate the turnover and nutrient release from tannin-containing manure, a litterbag experiment was conducted in an irrigated lowland soil of northern Oman. A standardized quebracho tannin extract (QT) was either added to the goats’ diet and defecated with manure (QTf), or added to manure in a QT water suspension (QTc) prior to field application. Litterbags were installed within a two-year field experiment at 10-cm depth at the beginning of a consecutive sweet corn and radish cultivation, followed by their recovery every 2-–6 weeks until crop harvests. The litterbags contained pure goat manure (control) and the two types of QT-amended goat manure. Generally, QT increased OM remaining in litterbags at sampling by up to 22% compared with the control. QT reduced relative C, N, P and K release by 10% to 63% compared with the control, but effects were contradictory under sweet corn and radish. While under radish, both QT treatments reduced or tended to reduce C, N, P and K release from manure, QTc even increased N and P release under sweet corn. QTf, on the other hand, did not affect C, P and K release under sweet corn, whereas N release was reduced by 36–63% under both crops. As quebracho tannins in goat manure slowed down organic matter decomposition and reduced nutrient release, they may be useful agents in manure application to increase SOM pools and soil nutrient pools. However, the immobilization particularly of N by tannins can reduce the availability of this nutrient to crops.

Durum wheat (Triticum durum) is one of the most important cereal crops in the Mediterranean region; however, its cultivation suffers from low yield due to environmental constrains. The main objectives of this study were to (i) assess genotype × environment (GE) interaction for grain yield in rainfed durum wheat and to (ii) analyse the relationships of GE interaction with genotypic/meteorological variables by the additive main effects and multiplicative interaction (AMMI) model. Grain yield and some related traits were evaluated in 25 durum wheat genotypes (landrace, breeding line, old and new varieties) in 12 rainfed environments differing in winter air temperature. The AMMI analysis of variance indicated that the environment had highest contribution (84.3% of total variation) to the variation in grain yield. The first interaction principal component axis (IPCA1) explained 77.5% of GE interaction sum of squares (SS), and its effect was 5.5 times greater than the genotype effect, indicating that the IPCA1 contributed remarkably to the total GE interaction. Large GE interaction for grain yield was detected, indicating specific adaptation of genotypes. While the postdictive success method indicated AMMI-4 as the best model, the predictive success one suggested AMMI-1. The AMMI biplot analysis confirmed a rank change interaction among the locations, indicating the presence of strong and unpredictable rank-change location-by-year interactions for locations. In contrast to landraces and old varieties, the breeding lines with high yield performance had high phenotypic plasticity under varying environmental conditions. Results indicated that the GE interaction was associated with the interaction of heading date, plant height, rainfall, air temperature and freezing days.

A monitoring study was carried out in Gumara watershed, upper Blue Nile basin, with the objective of evaluating livestock water productivity (LWP) using a life cycle assessment method. Sixty two smallholder farmers were selected for the study implemented between November 2006 and February 2008. Data on crop and livestock production were collected to allow assessment of livestock water productivity. Study sites were situated in three different rainfed mixed crop/livestock farming systems; barley/potato based system (BPS), tef/finger-millet based system (TMS), and rice/noug based system (RNS). LWP was found to be significantly lower (p < 0.01) in RNS (0.057 USD m−3 water) than in TMS (0.066 USD m−3 water) or in BPS (0.066 USD m−3 water). Notably, water requirement per kg live weight of cattle increased towards the lower altitude area (in RNS) mainly because of increased evapo-transpiration. As a result, 20% more water was required per kg live weight of cattle in the low ground RNS compared to BPS situated in the upstream parts of the study area. Cattle herd management that involved early offtake increased LWP by 28% over the practice of late offtake. Crop water productivity expressed in monetary units (0.39 USD m−3 water) was higher than LWP (0.063 USD m−3 water) across the mixed farming systems of Gumara watershed. Strategies for improving LWP, from its present low level, could include keeping only the more productive animals, increasing pasture productivity and linking production to marketing. These strategies would also ease the imbalance between the existing high livestock population and the declining carrying capacity of natural pasture.

Pearl millet [Pennisetum glaucum (L.) R. Br.] is grown as a forage, cover and grain crop in Brazil. Historically, forage production has the most important use, but during the last 30 years, the use as a cover crop in no-till soybean [Glycine max (L.) Merrill] production systems has expanded greatly and is currently used on over 5 million ha. Grain production as livestock feed is presently of minor importance but expanding. This review cites 125 references and documents pearl millet research conducted in Brazil which is largely published in Portuguese. The review addresses recommended pearl millet production practices for different uses, including stand establishment, row spacing and plant population, fertiliser and pest management, and the use of pearl millet in rotation and as a cover crop between soybean or maize (Zea mays L.) production to reduce crop losses from nematode infestation. It is concluded that greater research investment in crop improvement, fertiliser and pest management, nematode management, and forage/grain utilisation is needed to fully take advantage of pearl millet to meet feed, food and soil improvement needs in Brazil. In addition, creation of a database on pearl millet production, marketing and utilisation to assist farmers and grain merchandisers, and increased extension programming on pearl millet production is needed.

In Côte d'Ivoire, the world's largest cocoa producer, cacao (Theobroma cacao L.) is usually grown from seed. The genetics consist of a mix of amelonado, trinitario and selected hybrids. This mix of varieties generates high phenotypic variabilities, including variability in tree productivity, within cacao populations in both smallholder and industrial plantations. Tree-to-tree variability in yield has been reported in cacao breeding trials under different environmental conditions. However, it has never been considered a limiting factor for agronomical performance of seedling-based cacao plantations. Around 10 000 cacao trees from seven plots under different environmental conditions in a cacao plantation in Côte d'Ivoire were monitored for 2 years. Pod production of individual trees was recorded and annual average tree pod yields were assessed. High heterogeneity in cacao-tree yields was observed in all plots, with coefficients of variation ranging from 56 to 102%. The distribution of cacao-tree yields in each plot was positively skewed. Analysis of these distributions showed that unproductive trees represented a significant proportion of cacao tree populations (7%), and the 20% least productive trees accounted for 3% of production. The 20% most productive trees were responsible for 46% of the total pod production of a plot. This heterogeneity reflects a major imbalance in the agronomical performances of low- and high-yielding trees and also represents possible efficiency gaps in seedling-based cacao plantations, which could be overcome through innovative corrective strategies, opening new pathways for improvement of cacao-based cropping systems.

Successful fruit set in coconut depends on several reproductive processes including pollen germination and pollen tube growth. High temperature (˃33 °C) during flowering reduces fruit set in coconut. Therefore, identification and development of coconut varieties or hybrids with high reproductive heat tolerance will benefit the coconut industry in view of the climate changes. This experiment was conducted to quantify the response of pollen germination and pollen tube growth of seven coconut hybrids to increasing temperature from 16 to 38 °C. A Principal Component Analysis (PCA) was carried out to classify coconut hybrids on the basis of their temperature tolerances to pollen germination. Pollen germination and pollen tube length of the hybrids ranged from 56 to 78% and 242 to 772 µm, respectively. A modified bilinear model best described the response to temperature of pollen germination and pollen tube length. Cardinal temperatures (Tmin, Topt and Tmax) of pollen germination and pollen tube length varied among the seven hybrids. PCA identified Tmax for pollen germination and Topt for pollen tube length as the most important parameters in describing varietal tolerance to high temperature. PCA also identified SLGD × Sri Lanka Tall and Sri Lanka Brown Dwarf × Sri Lanka Tall as the most tolerant hybrids to high temperature stress and Sri Lanka Tall × Sri Lanka Tall and Sri Lanka Green Dwarf × San Ramon as less tolerant ones based on cardinal temperatures for pollen germination and pollen tube length. Tmax for pollen germination of the most tolerant and less tolerant hybrids were 41.9 and 39.5 °C, respectively. Topt for pollen tube length in the most tolerant and less tolerant hybrids were 29.5 and 26.0 °C, respectively.

Manganese (Mn) is one important microelement for plants and the human beings. This study was conducted to evaluate the potential of Mn nutrition in improving the productivity and grain biofortification of wheat. For optimization of Mn seed treatments, seeds were primed with 0.1 and 0.01 M Mn solution, or were coated with 250 and 500 mg Mn kg−1 seed. The optimized treatments were used in the second experiment replicated over time and space. In the first experiment conducted at Faisalabad during 2012–2013, maximum grain yield was recorded with Mn seed priming (0.1 M Mn solution), while maximum grain Mn concentration was recorded with foliar application of 0.75 M Mn solution and seed coating with 250 mg Mn kg−1 seed. In the second experiment, conducted at Faisalabad and Sheikhupura during 2013–2014, and at Faisalabad during 2014–2015, maximum grain yield and grain Mn concentration were recorded from seed priming with 0.1 M Mn solution. Regardless of method, Mn application improved the productivity and grain biofortification of wheat. Overall order of improvement in grain yield was seed priming (3.87 Mg ha−1) > foliar application (3.74 Mg ha−1) > seed coating (3.57 Mg ha−1). Regarding grain Mn concentration, the best treatment was seed priming (41.40 µg g−1) followed by seed coating (39.87 µg g−1) and foliar application (36.94 µg g−1). Maximum net returns and benefit-cost ratio were obtained with Mn seed priming, while maximum marginal rate of return was obtained with Mn seed coating. In conclusion, Mn application through seed treatments was cost effective for improving the productivity and grain biofortification of bread wheat in alkaline calcareous soil.

Shortages of hired labour are leading to greater interest in mechanisation for crop establishment in smallholder agriculture. Due to small field sizes, mechanised planters mounted on four-wheel tractors are not a suitable technology. The Versatile Multi-crop Planter (VMP) was developed for zero tillage (ZT), strip planting (SP) or single pass shallow tillage (SPST) on flat land and for forming and planting on tops of beds, each in a single pass operation, when mounted on a two-wheel tractor (2WT). The aim of the present study was to evaluate the field performance of the VMP in comparison to conventional broadcast seeding and full rotary tillage (2 to 4 passes; called CT) for establishing chickpea (Cicer arietinum L.), jute (Corchorus olitorius L.), lentil (Lens culinaris Medikus), maize (Zea mays L.), mung bean (Vigna radiata L. R. Wilczek), rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in 15 locations of Bangladesh. Plant populations emerging from all single pass operations viz. SP, ZT, and bed planting (BP) were generally satisfactory and in 12 out of 15 experiments plant populations after SP were similar to or greater than after CT. In addition, SP gave comparable or greater plant populations than SPST and BP planting methods. Overall, the SP planting achieved comparable yields and lower costs of establishment than CT. We conclude that effective and reliable planters are now available for sowing a range of crop species on small fields with minimum soil disturbance. This opens up realistic options for the development of mechanised conservation agriculture suited to small field sizes.

Using a qualitative case study design, a demonstration farm approach implemented in northern Patagonia, Argentina, was assessed to examine differences in perceptions between participating stakeholder groups regarding their roles and how these affect the collaboration process. Moreover, differences in stakeholder perceptions regarding positive impacts and constraints of the implemented innovation (supplemental feeding of small ruminants) were assessed, as one exemplary innovation to improve low-external-input pastoral livestock systems. Three cases of demonstration farm projects were selected and a total of 31 semi-structured and narrative interviews were carried out with participating livestock keepers, extension workers and scientists. Together with information gained by employing visual tools and participant observation, data was analysed using qualitative content analysis. Results reveal that major decisions regarding the collaboration process were taken by scientists in advance, hence, livestock keepers' participation was used to meet predetermined objectives, which is characteristic to the concept of functional participation. While scientists seemed to transfer the control principles of on-station research to the on-farm situation, extension workers recognised the need for replacing teaching by the aim of creating learning opportunities. Here, incongruences in role understanding indicate an overall lack of joint role definition and the need of balancing power differences. Livestock keepers' perceptions of the supplemental feeding strategy highlight substantial management constraints for implementation, which were not recognised by scientists and extension workers, nor were they captured by the monitoring system implemented. We recommend furnishing the demonstration farm approach with principles, methods and tools of collaborative learning, to create a change in actors' understanding of roles and to induce a shift towards increased transdisciplinarity.

Potassium chloride (KCl) is the most widely used fertilizer in oil palm (Elaeis guineensis) plantations and the rates applied are based on interpretation of leaf K contents. When no positive response on leaf K contents can be detected, no optimum content can be established whatever the yield response to KCl rates. We used data from 13 fertilization trials conducted on several continents to study the responses of leaf K, leaf Cl, leaf Ca and yield to KCl rates as a function of the soil properties of each site. We found that the abundance of exchangeable Ca in the soil expressed as a percent of the cation exchange capacity (CEC) was the best soil variable to predict if leaf K content would increase with KCl rates. In addition, we found that the leaf K contents of unfertilized controls at the end of the trials were also correlated with Ca/CEC. This ratio thus appears to be a better index of soil K reserves than soil exchangeable K content.