The effects of scales, flows and filters on property rights and collective action in watershed management:

Research and policy on property rights, collective action and watershed management requires good understanding of ecological and socio-political processes at different social-spatial scales. On-farm soil erosion is a plot or farm-level problem that can be mitigated through more secure property rights for individual farmers, while the sedimentation of streams and deterioration of water quality are larger-scale problems that may require more effective collective action and / or more secure property rights at the village or catchment scale. Differences in social-political contexts across nations and regions also shape property rights and collective action institutions. For example, circumstances in the Lake Victoria basin in East Africa require particular attention to collective action and property rights problems in specific “hot spot” areas where insecure tenure leads to overuse or under-investment. Circumstances in the uplands of Southeast Asia require analysis of the opportunities for negotiating more secure rights for farmers in exchange for stronger collective action by farmer groups for maintaining essential watershed functions.

Reconciling root plasticity and architectural ground rules in tree root growth models with voxel automata

Contacts: [email protected] models of tree root growth and function have to reconcile the architectural rules for coarse root topology with the dynamics of fine root growth (and decay) in order to predict the strategic plus opportunistic behaviour of a tree root system in a heterogeneous soil. We present an algorithm for a 3D model based on both local (soil voxel level) and global (tree level) controls of root growth, with development of structural roots as a consequence of fine root function, rather than as driver. The suggested allocation rules of carbon to fine root growth in each rooted voxel depend on the success in water uptake in this voxel during the previous day, relative to overall supply and demand at plant level. The allocated C in each voxel is then split into proliferation (within voxel growth) and extension into neighbouring voxels (colonisation), with scale-dependent thresholds and transfer coefficients. The fine root colonisation process defines a dynamic and spatially explicit demand for transport functions. C allocation to development of a coarse root infrastructure linking all rooted voxels depends on the apparent need for adjustment of root diameter to meet the topologically defined sap flow through this voxel during the previous day. The allometric properties of the coarse root system are maintained to be in line with fractal branching theory. The model can predict the dynamics of the shape and structure (fine root density, coarse root topology and biomass) of the root system either independently of soil conditions (purely genetically-driven) or including both the genetic and environmental effects of roots interacting with soil water supply and its external replenishment, linking in with existing water balance models. Sensitivity of the initial model to voxel dimensions was addressed through explicit scaling rules resulting in scale-independent parameters. The model was parameterised for two tree species: hybrid walnut (Juglans nigra x regia) and wild cherry (Prunus avium L.) using results of a pot experiment. The model satisfactorily predicted the root growth behaviour of the two species. The model is sparse in parameters and yet applicable to heterogeneous soils, and could easily be upgraded to include additional local influences on root growth (and decay) such as local success in nutrient uptake or dynamic soil physical propertie

Does income imply food security in coffee growing communities? A case study in Yayu, Southwestern Ethiopia

The impacts on food security of a transition from agriculture focused on local consumption to the participation in global markets are uncertain, with both positive and negative effects reported in the literature. In Ethiopia, coffee production for global markets has attracted growers from across the country to the coffee-forest zones. From a national perspective, the area is not a priority for food security enhancement, as financial indicators suggest food sufficiency. In this setting, we collected food security and dietary intake data from a total of 420 (3X140) units of households, non-breast-feeding children under 5 years, and women of reproductive age. Sampling was done in two-stages, a random selection of 300 households (out of a total of 4,300) Yayu, followed by sub-sampling of households with a child and woman meeting the above-mentioned criteria. Samples were used to determine a number of food and nutrition security indicators. More than 83% of the households were found to be hunger-free in the shortage season, but dietary diversity was suboptimal. More than 50% of children under 5 years of age and women lacked foods containing heme iron in the surplus season and 88% in the shortage season. Household food security during the surplus season did not depend on income, but wealth was significantly correlated (p < 0.01) with all of the food insecurity indicators except the “Body Mass Index” of target women in the shortage season. The strongest and weakest correlation was with the “House Food Insecurity Access Scale” (−0.85), and “Weight-to-Age Z-Score” (0.25), respectively. Overall, Yayu is not fully food secure, though the situation is better than average for the country. While household income helps in achieving calorific sufficiency, greater awareness of the relevance of dietary diversity and the local means to achieve it is needed to further improve nutritional status, regardless of the participation in global markets

Relational values in locally adaptive farmer-to-farmer extension: how important?

Values held in agricultural extension systems determine which extension goals can be reached. Globally changing socio-ecological contexts require a paradigm shift in agricultural extension systems from a top-down approach dominated by instrumental values to achieve the primary goal of increasing yields, to a more site-specific relational and participatory approach that induces locally adaptive use of sustainable agricultural practices. A literature review was conducted to understand how relational values in farmer-to-farmer extension align with participatory agricultural extension systems. Relevance, trust, and place attachment are the main relational values expressed in farmer-to-farmer extension where participatory processes incorporate farmers' livelihood outcomes in the transformational goals of agricultural extension. Recognizing and strengthening the relational values in farmer-to-farmer extension, based on different contexts, will likely support the development of locally adapted knowledge and innovations, and provide a basic rationale for building communication strategies, colearning, and supporting behavioral change of all agricultural extension actors

SANDALWOOD AS A COMPONENT OF AGROFORESTRY: EXPLORATION OF PARASITISM AND COMPETITION WITH THE WANULCAS MODEL

Sandalwood is an important component of agroforestry systems in the drier Eastern parts of Indonesia, although its value to farmers is still limited by existing policies and regulation of marketing. As a relatively slow growing root parasite, sandalwood will interact with other components in a complex pattern of competition and host-parasite relationships, depending on root distribution and rooting depth of potential hosts. We describe a number of modifications to the generic tree-soil-crop simulation model WaNuLCAS, that allow exploration of the transition between parasitism and competition. The key variable in this transition is the effectiveness of formation of the parasitic link for all situations where roots of the host and parasite occur in the same volume of soil. At low values of this effectiveness competition dominates, at higher values sandalwood will weaken the host, until it effectively kills it, leading to an optimum response of sandalwood to the effectiveness parameter. Unresolved questions in the formulation of the model are the lifespan of parasitized roots and the question whether or not sandalwood will allocate energy resources for maintenance respiration of host roots after the formation of haustoria. The'desk study' reported here was intended to focus subsequent field studies on these unresolved issues

Knowledge gaps and research needs concerning agroforestry's contribution to Sustainable Development Goals in Africa

This review addresses the role of agroforestry in the links between food security and agricultural sustainability in Africa. We illustrate that the products and services flowing from the integration of trees within farming systems can contribute to food security, farmer livelihoods and environmental resilience. However, for agroforestry to be adopted it should not be constrained by policies which hinder the integration of trees, with crops and livestock. This policy scenario can best be met when the governance of food production at local to global scales is multi-sectoral and based on a ‘Systems Approach’. Nevertheless, the adoption of agroforestry has recently been greatly supported by the international agenda on the mitigation of climate change and to achieve sustainable food production. In conclusion we pose the hypothesis that “Agroforestry concepts and practices can form an effective, efficient and fair pathway towards the achievement of many Sustainable Development Goals”, and discuss the main messages and research questions emerging from the papers presented in this special issue

Pendugaan Biomassa Pohon Berdasarkan Model Fractal Branching pada Hutan Sekunder di Rantau Pandan, Jambi

Fractal branching analysis is a model of indirect estimation on tree biomass that based on the diameter and length of branches. This model put on assumption that the stem diameter before and after branching have the same value which formulated into functional relationship Y = a Db. The research aimed to find out the equation estimation of rubber trees biomass then compared to the equation of corrected biomass after Brown (1997). From this study, it has been found that the equation of above ground biomass for rubber trees is Y = 0.095 D2.62 and non rubber trees Y = 0.091 D2.59 while the equation of aboveground biomass after Brown (1997) is Y = 0.092 D2.60. Based on that grouping in which fractal branching model as a simulation of the Brown model has resulted the same graph. Beside that, the advantage of using this model is that the weight of stem should not be measured because tree biomass can be estimated by measuring the stem diamete

Tree Establishment on Post-Mining Waste Soils: Species, Density, and Mixture Effects

Tree establishment to restore degraded boreal post-mining lands is challenged by low soil productivity, a harsh microclimate, and potentially high contaminant levels. The use of mixed vegetation can facilitate the microclimate but increase competition for soil resources. A statistical accounting of plant–plant interactions and adaptation to multispecies conditions is hard to achieve in field experiments; trials under controlled conditions can distinguish effects of planting density and species interactions in the early stages of plant establishment. A greenhouse trial was established in containers (“mesocosms”) with waste rock or fine tailings from gold mines. Pregerminated (1-week-old) seedlings (Alnus viridis subsp. crispa, Picea glauca, Populus tremuloides, Salix arbusculoides) were planted using a Nelder density gradient design, modified for species combinations. A relative competition effect was estimated as a competitiveness index for each species combination, calculated as a ratio of α coefficients in the Holliday growth equation. The specific leaf area (SLA) was measured to indicate plant water stress adaptation. All species grew better in monoculture on fine tailings, while only P. tremuloides grew better in all mixtures on waste rock. Although net positive effects of density on SLA increment during early growth suggested microclimate improvement on fine tailings, no mixture provided advantages for both species in paired combinations

Pendugaan Biomassa Pohon Berdasarkan Model Fractal Branching pada Hutan Sekunder di Rantau Pandan, Jambi

Fractal branching analysis is a model of indirect estimation on tree biomass that based on the diameter and length of branches. This model put on assumption that the stem diameter before and after branching have the same value which formulated into functional relationship Y = a Db. The research aimed to find out the equation estimation of rubber trees biomass then compared to the equation of corrected biomass after Brown (1997). From this study, it has been found that the equation of above ground biomass for rubber trees is Y = 0.095 D2.62 and non rubber trees Y = 0.091 D2.59 while the equation of aboveground biomass after Brown (1997) is Y = 0.092 D2.60. Based on that grouping in which fractal branching model as a simulation of the Brown model has resulted the same graph. Beside that, the advantage of using this model is that the weight of stem should not be measured because tree biomass can be estimated by measuring the stem diamete