Productivity Of Agroforestry Systems Research Articles

Biophysical drivers of yield gaps and ecosystem services across different coffee-based agroforestry management types: A global meta-analysis

The productivity of agroforestry systems (AFSs) and the provisioning of associated ecosystem services (ESs) are threatened by increasing cropping intensification and climate change. Compared to full-sun coffee, maintaining shade cover might protect against climate variability, forest degradation, and pests/diseases attack. However, there may be trade-offs between yields and ESs. While the impacts of shade have been reviewed, a global synthesis to understand how shade trees and a range of practices and biophysical factors contribute to yield gaps and ESs across management types is lacking. This research aims at integrating quantitative data on management practices (shade cover percentage, tree/coffee plant densities, and nutrient inputs), coffee/tree characteristics, soil properties, topographic attributes and climate, in order to compare the responses of coffee yields, biodiversity and ES supply across management types. We conducted a meta-analysis with a total of 142 papers that fulfilled the inclusion criteria and analyzed the individual and combined effects of these factors. The results show that factors such as shade cover and tree/plant densities affected more the yields than climatic and biotic factors. AFSs under moderate shade cover levels (35–50%), with tree densities between 100 and 250 trees ha−1, at low altitudes, and with steeper slopes provided as much yields as full-sun systems (4.1 ± 2.88 tons ha−1 yr−1). While increased shade cover (>51%) decreased yields, the results also show that more diversified AFSs can support biodiversity conservation and provide ESs such as stored carbon, infiltration, pollination, and water runoff. The generalized linear models (GLMs) analyses showed that coffee yield variations are highly context-dependent and factors such as the incidence of pest/leaf rust, altitude, soil quality, available water, and biodiversity may play an important role. The novelty of this research is that the effect of shade, coffee plants, and input management practices is taken into account, along with the effects of a range of site-specific biophysical factors; along with the application of a case study to test robustness of the meta-analysis. This study provides an understanding of the effects of management type gradients on coffee yield and whether the low yields in AFSs compared to conventional coffee monocultures, are compensated by the provisioning of ESs.

Application of molecular markers for the comprehensive improvement of agro-forestry communities for the development of sustainable agriculture

Relevance and methods. Analysis of state-of-the-art and perspectives in use of molecular (DNA-based) markers in current horticulture and agroforestry was performed.Results. We showed use of molecular markers for screening of crop varieties with elevated synthesis of human health beneficial metabolites. Molecular markers have not been used to improve varieties of trees yet. Complex use of molecular markers for variety screening and breeding of food crops and forest trees could improve sustainability and productivity of agroforestry systems.

Effects of temperate agroforestry on yield and quality of different arable intercrops

Agroforestry systems (AFS) are considered to be a sustainable agricultural practice, as they deliver a wide range of ecosystem services (ES) while maintaining (agricultural) primary production. To optimize the productivity of AFS, the recommendation is to use well adapted tree-crop combinations, thereby limiting competition for resources and maximizing synergies. However, yield and quality data on arable crops in temperate AFS are scarce, in particular for AFS with a mature tree component. Here we assessed the influence of tree rows of contrasting age on yield and quality of key western European arable crops. We focused on (forage) maize, potato, winter wheat and winter barley during three consecutive years (2015–2017) on a set of 16 arable agroforestry fields in Belgium comprising 6 young (2–7 year old) alley cropping fields and 10 fields bordered by a row of deciduous trees of moderate to older age (15–48 years old). Both tree age and crop type were key determinants of yield and quality of the investigated arable crops. While effects on crop yield were limited for all crops near young tree rows, substantial yield reductions were observed near mature trees, in particular for maize and potato (both summer crops). Effects on crop quality were limited for all crops under study, with substantial effects only arising near the oldest tree rows. To optimize the provisioning service of AFS, the cultivation of winter cereals may be advisable over maize and potato towards the end of the rotation of an AFS. In addition, poplar trees should be harvested when they reach their target diameter for industrial processing. If tree rows are preserved for the delivery of other ES, however, substantial impacts on crop yield and quality should be taken into account.

Research advances in plant competition in agroforestry systems

Plant competition plays an important role in the success and sustainability of agroforestry systems. Minimizing competi- tion and maximizing resource utilization increase crop yield and overall productivity of agroforestry systems. This paper introduces the concept and theory of plant competition, reviews competition for light, water and nutrient among trees and crops, and summarizes allelopathy and competition related plant traits in agroforestry systems. Aboveground competition for light among trees and crops is a major constraint under humid climate conditions, while belowground competition for water predominates in semi-arid tropics and temperate agroforestry systems. In agroforestry systems, plant competitive ability for light is decided by leaf area, canopy structure, et al. Root traits related to belowground competitive ability include occupied soil space, morphological and physical elasticity and spatial and temporal soil partitions. It is suggested that future research on agroforestry systems focus on comparisons among different components in different climatic conditions, competition processes and physiological mechanisms, plant allelopathy and the role and mechanism of mycorrhizae in plant competition, interactions between above- and below-ground competition and the effect of global climate change on plant competition of the agroforestry systems.

Napier grass strips and livestock: a bioeconomic analysis

Napier grass strips are gaining some acceptance in Southeast Asia as a vegetative means of soil erosion control, due to the relative ease of establishment and management. In addition, the napier grass strips aid productivity of agroforestry systems by providing mulch or by being fed to livestock. In this paper, a bioeconomic comparison of different ways of utilising the napier grass cuttings is undertaken. The three uses examined for the cuttings were: as mulch in the alley areas, sold as fodder, and fed to animals with manure applied back to the system. The analysis linked the soils-oriented SCUAF model with economic and animal component models. SCUAF was parameterized using field data based on farmer interviews and field visits. Farmer interviews and field visits were conducted at Claveria, Misamis Oriental to gather additional data regarding costs and returns associated with animal production, and also to obtain the farm gate price of napier. Predicted biophysical results produced by the SCUAF model showed that application of napier grass cuttings, back into the system, directly as mulch or indirectly as animal manure resulted in higher maize and napier yields, lower soil erosion rates, and less of a reduction in soil mineral nitrogen and soil labile carbon levels. The comparison was made with the case where napier was sold off-farm as fodder. Cost-benefit analysis showed that higher economic returns were gained when napier grass cuttings were fed to animals, rather than applied directly as mulch. This economic benefit was attributed to the draught and transport services rendered by the animal and to a change in the value of the animals. This analysis highlights the value of utilizing animals within a napier grass strip system for control of erosion.

Atmospheric carbon sequestration through agroforestry in China

Agroforestry is an important alternative to modern agriculture and forestry. It is useful in ameliorating environmental degradation, such as desertification and land erosion. During our study on biomass and productivity of agroforestry systems in the North China Plain, we found that agroforestry has a greater potential for storing and absorbing carbon from the atmosphere than has land cultivation. Furthermore, agroforestry systems produce timber and firewood that will bring profit to peasants and reduce the release of CO 2 into the atmosphere.