scholarly journals Role of Indigenous Dryland Agroforestry System for Biodiversity Conservation and Carbon Storage in Tigray, Northern Ethiopia

2020 ◽  
Author(s):  
Ashenafi Manaye ◽  
Berihu Tesfamariam ◽  
Musse Tesfaye ◽  
Adefires Werku ◽  
Yirga Gufi

Abstract Background Agroforestry (AF) is an age-old practice in the farming system of Ethiopian dry lands. So far, several studies conducted in the field of AF focused on system design, soil fertility management and system interactions. Less emphasis has been given to the biodiversity and climate change mitigation aspects. The objective of this paper was to evaluate the woody species diversity, biomass carbon (C) and soil organic carbon (SOC) stock of the dry land indigenous AF practices. A total of 197 smallholder farmers representing four AF practices were systematically selected from lowland, midland and highland. Woody species inventory was done on the randomly established plot of each farm. Results A total of 59 species, belonging to 48 genera and 32 families were recorded. Shannon diversity index (H’) of highland agroecology was higher in-home garden AF while in the midland and lowland the higher H’ was recorded in parkland AF. Smallholding ecosystem C stocks (sum of total biomass C and SOC 0 –60 cm) ranged from 77 to 135 Mg ha −1 .The mean total biomass C stock of woodlot AF practice (31 Mg C ha -1 ) was significantly higher than the other three AF practices. SOC stocks (0–60 cm) were greater in boundary planting (113 Mg C ha -1 ) followed by the home garden (109 Mg C ha -1 ) and woodlot (97 Mg C ha -1 ) AF practices. Conclusions The higher species richness was recorded on the home garden and parkland small household agroforestry system as compared to woodlot agroforestry systems. Likewise, the higher Shannon diversity and evenness were found on the home garden agroforestry system.. As compared to other AF systems, our study revealed that rotational woodlot and boundary planting AF practice accounts higher biomass and SOC stock, respectively. We found that biodiversity is synergy with SOC stock but can be seen as an independent agro-ecosystem function that may not directly correlated to biomass and total agroforestry carbon storage. Finally, our work concluded that home garden and boundary agroforestry can strategically promote to maximize biodiversity and carbon storage of the dry land ecosystem.

2019 ◽  
Author(s):  
Ashenafi Manaye ◽  
Berihu Tesfamariam ◽  
Musse Tesfaye ◽  
Adefires Werku ◽  
Yirga Gufi

Abstract Background : Agroforestry (AF) is an age-old practice in the farming system of Ethiopian dry lands. So far, several studies conducted in the field of AF focused on system design, soil fertility management and system interactions. Less emphasis has been given to the biodiversity and climate change mitigation aspects. The objective of this paper was to evaluate the woody species diversity, biomass carbon (C) and soil organic carbon (SOC) stock of the dry land indigenous AF practices. A total of 197 smallholder farmers representing four AF practices were systematically selected from three agroecologies. Woody species inventory was done on the randomly established plot of each farm. Results : A total of 59 species, belonging to 48 genera and 32 families were recorded. Shannon diversity index (H’) of highland agroecology was higher in-home garden AF while in the midland and lowland the higher H’ was recorded in parkland AF. Smallholding ecosystem C stocks (sum of total biomass C and SOC 0 –60 cm) ranged from 77 to 135 Mg ha−1.The mean total biomass C stock of woodlot AF practice (31 Mg C ha-1) was significantly higher than the other three AF practices. SOC stocks (0–60 cm) were greater in boundary planting (113 Mg C ha-1) followed by the home garden (109 Mg C ha-1) and woodlot (97 Mg C ha-1) AF practices. Conclusions : The woody species diversity of highland agroecology was higher in-home garden AF while in the midland and lowland the higher species diversity was recorded in parkland AF. As compared to other AF systems, our study revealed that rotational woodlot and boundary planting AF practice accounts higher biomass and SOC stock, respectively. Finally, our work concluded that indigenous AF system is a win-win solution to address the biodiversity conservation and climate change mitigation of the dryland ecosystem.


2012 ◽  
Vol 9 (8) ◽  
pp. 3381-3403 ◽  
Author(s):  
T. R. Feldpausch ◽  
J. Lloyd ◽  
S. L. Lewis ◽  
R. J. W. Brienen ◽  
M. Gloor ◽  
...  

Abstract. Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions: 1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass? 2. To what extent does including H estimates derived in (1) reduce uncertainty in biomass estimates across all 327 plots? 3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06), was half that when excluding H (mean 0.13). Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D) that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4) to 8.0 Mg ha−1 (−2.5 to 23.0). For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI), or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly more biomass in small diameter stems, which affects selection of the best height models to reduce uncertainty and biomass reductions due to H. After accounting for variation in H, total biomass per hectare is greatest in Australia, the Guiana Shield, Asia, central and east Africa, and lowest in east-central Amazonia, W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if tropical forests span 1668 million km2 and store 285 Pg C (estimate including H), then applying our regional relationships implies that carbon storage is overestimated by 35 Pg C (31–39 bootstrapped 95% CI) if H is ignored, assuming that the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree H is an important allometric factor that needs to be included in future forest biomass estimates to reduce error in estimates of tropical carbon stocks and emissions due to deforestation.


Author(s):  
Samson Shimelse Jemaneh

This study was conducted with the objectives of study investigates, compare, and try to describe the floristic composition and structure of the vegetation of exclosures and open grazing lands. A stratified preferential sampling design technique with flexible systematic model was used for data collection. Data on vegetation and environmental parameters were gathered from 120 quadrants (90 from restorations or exclosures of different ages and 30 from adjacent open grazing lands), of 20 m x 20 m (400 m2) size. Species richness and the presence or absence of herbaceous plants were recorded like soil samples in a 2 m x 2 m (4 m2) subplot inside each main quadrant from five points, one at each corner and one at the center.  A total of 142 plant species belonging to 118 genera and 52 families were identified. All exclosures displayed higher plant species richness, diversity, and aboveground standing biomass compared to the adjacent open grazing lands. Consideration of edaphic (e.g. soil total nitrogen, available phosphorus, CEC, exchangeable bases, soil pH and soil texture) and site (e.g. Stoniness, Grazing) variables will help to optimize the selection of areas for the establishment of future exclosures. Moreover, our study suggests that with time exclosures may increasingly obtain an important role as refugees and species pool similar to church forests and should be protected and managed in a sustainable manner. However, economic and social impacts of exclosures should be included in feasibility studies before establishing exclosures in the future.  Altitude, Grazing and some soil parameters like Mg were the major environmental factors in the division of the vegetation into plant community types. The result of the frequency distribution of woody species showed a high proportion of small-sized individuals in the lower diameter classes indicating good recruitment potential of the forest patches and the rare occurrence of large individuals. Such trend was probably caused by past disturbance of the original vegetation resulting in a succession of secondary vegetation. In addition, the analysis of species population structure indicated that some tree species had abnormal population structure with no or few individuals at lower size classes. Moreover, assessment of regeneration status on the basis of age classes indicated that significant proportion of woody species were represented by few or no seedlings, entailing that they were under threat. Substantial numbers of forest species were found to have irregular population structure and are in reduced regeneration status. To prevent local extinction of these species, present efforts of nursery establishment and plantation of indigenous species in the exclosures should be strengthened and extended.


Author(s):  
K.K. Vikrant ◽  
D.S. Chauhan ◽  
R.H. Rizvi

Climate change is one of the impending problems that have affected the productivity of agroecosystems which calls for urgent action. Carbon sequestration through agroforestry along altitude in mountainous regions is one of the options to contribute to global climate change mitigation. Three altitudes viz. lower (286-1200m), middle (1200-2000m), and upper (2000-2800m) have been selected in Tehri district. Ten Quadrates (10m × 10 m) were randomly selected from each altitude in agrisilviculture system. At every sampling point, one composite soil sample was taken at 30 cm soil depth for soil organic carbon analysis. For the purpose of woody biomass, Non destructive method and for crop biomass assessment destructive method was employed. Finally, aboveground biomass (AGB), belowground biomass carbon (BGB), Total tree Biomass (TTB), Crop biomass (CB), Total Biomass (TB), Total biomass carbon (TBC), soil organic carbon (SOC), and total carbon stock (TC) status were estimated and variables were compared using one-way analysis of variance (ANOVA).The result indicated that AGB, BGB, TTB, CB , TB, TBC, SOC, and TC varied significantly (p < 0.05) across the altitudes. Results showed that total carbon stock followed the order upper altitude ˃ middle altitudes ˃ lower altitude. The upper altitude (2000-2800 m) AGB, BGB,TTB, TBC,SOC, and TC stock was estimated as 2.11 Mg ha-1 , 0.52 Mg ha-1, 2.63 Mg ha-1, 2.633 Mg ha-1, 1.18 Mg ha-1 , 26.53 Mg ha-1, 38.48 Mg ha-1 respectively, and significantly higher than the other altitudes. It was concluded that agrisilviculture system hold a high potential for carbon storage at temperate zones. Quercus lucotrichophora, Grewia oppositifolia and Melia azadirach contributed maximum carbon storage which may greatly contribute to the climate resilient green economy strategy and their conservation should be promoted.


1983 ◽  
Vol 13 (3) ◽  
pp. 372-383 ◽  
Author(s):  
W. Carter Johnson ◽  
David M. Sharpe

Records of merchantable forest volumes can be used to estimate rates of carbon storage or depletion using a ratio to convert merchantable weights to total forest biomass (T/M ratio). We present evidence that the T/M ratio used to estimate carbon storage in midlatitude forests has been seriously underestimated by neglecting carbon in trees of unmerchantable size and quality and in coarse and fine litter. Ratios for forest types and size classes in Virginia based on detailed plot-level analysis ranged from 2.1 to 5.0; the mean weighted ratio of 2.7 was 55% greater than a ratio currently in use. More general analysis indicated that the T/M ratio for Virginia was representative of forests of the East; forests of the western United States were comparable to those of the East when woody debris was included in the estimate of total biomass. Application of the weighted ratio to growth of United States forests during 1952–1977 yielded a per-annum accretion of carbon in biomass (excluding soil carbon) of 0.15 Gt C•year−1, about 10% of the 1.6–1.9 Gt C•year−1 computed for midlatitude forests. More complete studies of counterbalancing carbon losses from forests, particularly losses in litter and soils after forest harvest and conversion to agriculture, are needed before the source or sink nature of midlatitude forests can be determined with confidence.


2014 ◽  
Vol 14 (2) ◽  
pp. 103-108 ◽  
Author(s):  
S Bhandari ◽  
S Bam

The study was carried out in Chovar village of Kritipur Municipality, Kathmandu to compare the soil organic carbon (SOC) of three main land use types namely forest, agricultural and barren land and to show how land use and management are among the most important determinants of SOC stock. Stratified random sampling method was used for collecting soil samples. Walkley and Black method was applied for measuring SOC. Land use and soil depth both affected SOC stock significantly. Forest soil had higher SOC stock (98 t ha-1) as compared to agricultural land with 36.6 t ha-1 and barren land with 83.6 t ha-1. Similarly, the SOC in terms of CO22-1, 79.27 to 22.02 CO2-e ha-1 and 121.11 to 80.74 CO2-1 for 0- 20 cm to 40-60 cm soil depth, respectively. Bulk density (BD) was found less in forest soil compared to other lands at all depths, which showed negative correlation with SOC. The study showed a dire need to increase current soil C stocks which can be achieved through improvements in land use and management practices, particularly through conservation and restoration of degraded forests and soils.   DOI: http://dx.doi.org/10.3126/njst.v14i2.10422   Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 103-108


Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 64 ◽  
Author(s):  
Fiona Robertson ◽  
Doug Crawford ◽  
Debra Partington ◽  
Ivanah Oliver ◽  
David Rees ◽  
...  

Increasing soil organic carbon (SOC) storage in agricultural soils through changes to management may help to mitigate rising greenhouse gas emissions and sustain agricultural productivity and environmental conditions. However, in order to improve assessment of the potential for increasing SOC storage in the agricultural lands of Victoria, Australia, further information is required on current SOC levels and how they are related to environmental conditions, soil properties and agricultural management. Therefore, we measured stocks of SOC at 615 sites in pasture and cropping systems in Victoria, encompassing eight regions, five soil orders and four management classes (continuous cropping, crop–pasture rotation, sheep or beef pasture, and dairy pasture), and explored relationships between the C stocks and environment, soil and management. The results showed an extremely wide range in SOC, from 2 to 239 t C/ha (0–30 cm). Most of this variation was attributable to climate; almost 80% of the variation in SOC stock was related to annual rainfall or vapour pressure deficit (i.e. humidity). Texture-related soil properties accounted for a small, additional amount of variation in SOC. After accounting for climate, differences in SOC between management classes were small and often not significant. Management practices such as stubble retention, minimum cultivation, perennial pasture species, rotational grazing and fertiliser inputs were not significantly related to SOC stock. The relationships between SOC and environment, soil and management were scale-dependent. Within individual regions, the apparent influence of climate and soil properties on SOC stock varied, and in some regions, much of the variation in SOC stock remained unexplained. The results suggest that, across Victoria, there is a general hierarchy of influence on SOC stock: climate > soil properties > management class > management practices.


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