ALBERT

Description: This study evaluates the efficacy of Improved Forest Management for Sustainable Livelihoods Program in communities adjacent to Mua-Livulezi Forest Reserve, Malawi. The program is specifically aimed at alleviating poverty and enhance rural livelihoods through promoting greater community involvement in forest management while providing access and associated benefits. The study therefore evaluated the effect of the program on community organisation, forest access, forest use, product availability and commercialisation of forest products. The results show that despite the program putting in place strategies for the people to access different products for different uses; forest use is restricted mainly to subsistence use rather than cash income. The main forest product collected by the people for livelihood was firewood, mainly for cooking and heating. This is an indication that forests are an important natural capital for subsistence rather than cash income. Gender, location of the village, and distance to the nearest forest area were significant predictors of households’ forest use. Introduction of the co-management program has not brought out the expected outcomes in areas of community organization, forest access, forest product availability and commercialisation of forest products. A multi-institutional approach is recommended to draw upon diverse talents and experiences from individual institutions both government and non-governmental in order to achieve meaningful social change.

Description: Rhizosphere carbon sequestration plays a crucial role in soil carbon dynamics. Little information is available on the dynamics of rhizosphere soil labile organic carbon fractions compared with bulk soil at different citrus stand age. Two replicate sites of three stand ages (10-, 20-, and 30-year) of citrus in the Three Gorges Reservoir area of China were studied. The results showed that rhizosphere soil organic carbon has an increases of 18.76 % under 20-year stand and 11.09 % under 30-year stand compared with bulk soil (P 〈 0.05), respectively. The dissolved organic C of rhizosphere soil was 31.32, 19.57 and 31.81 % higher compared with bulk soil under 10-, 20- to 30-year stands (P 〈 0.05), respectively, whereas readily oxidizable organic C (ROC) was 50.47, 70, and 64.54 % higher (P 〈 0.05). Microbial biomass (MBC) and water-soluble carbohydrate (WSCh) had no significant difference between rhizosphere and bulk soils in the 10- and 20-year stands, whereas a 9.88 % lower for MBC and a 36.47 % higher for WSCh in rhizosphere soil compared with bulk soil under 30-year stand were found (P 〈 0.05). Rhizosphere soil respiration showed a significantly negative relationship with ROC (r = 0.51, P 〈 0.05), WSCh (r = 0.60, P 〈 0.01) and MBC (r = 0.68, P 〈 0.01). The effect of the citrus rhizosphere on measured soil labile organic carbon fractions differed for each citrus stand age.

Description: Pyrus communis ‘Rocha’ is an economically important crop very susceptible to the pathogenic fungus Stemphylium vesicarium , the causal agent of brown spot disease. Knowledge on the complexity of mechanisms responsible for resistance to S. vesicarium infection is necessary for definition of strategies to improve defence responses in susceptible cultivars. To investigate the molecular mechanisms behind Pyrus communis defence responses to S . vesicarium , a 6624 (3312 × 2) cDNA microarray was constructed to identify genes differentially expressed between a resistant/tolerant cultivar (‘Ercolini’) and a susceptible cultivar (‘Rocha’). Both cultivars were compared to evaluate their genetic background differences prior to inoculation (T0h) and transcriptional changes along a time course infection with S. vesicarium (T6h and T24h). Two cDNA libraries, from ‘Rocha’ and ‘Ercolini’ pear cultivars, spotted in the microarray resulted on 146 differential expressed genes. Transcriptome analysis revealed several transcripts related to stress and defence, namely peroxidases, 3-dehydroquinate dehydratase/shikimate 5-dehydrogenase, thiazole biosynthetic enzyme, serpins, cytochromes P450, 2-methyl-6-phytylbenzoquinone methyltransferase, 6-phosphogluconate dehydrogenase, polyneuridine-aldehyde esterase precursor, lipoxygenases and PR proteins. The results suggest that resistance/tolerance of ‘Ercolini’ cultivar may result from the rapid activation of defence mechanisms while in ‘Rocha’ cultivar the defence mechanisms may be activated too late for inducing an efficient response to infection by S. vesicarium . Cell wall strengthening and biosynthesis of antifungal compounds may constitute efficient physical and chemical barriers to S. vesicarium infection and priming emerges as a putative mechanism of resistance/tolerance. The evidence gathered combined with knowledge on host/endophyte signalling in mycorrhiza leads us to suggest priming as a measure to brown spot disease control in ‘Rocha’ pear cultivar through symbiosis with mycorrhizal fungi in order to anticipate and induce a more efficient activation of defence mechanisms. Also the thiazole biosynthetic enzyme and the serpins appears as potential candidates for the development of molecular markers for resistance to infection.

Description: Agroforestry systems (AFS) play a major role in the sequestration of carbon (C). The objectives of this study were to quantify the organic C stocks in the above- and below-ground tree biomass and in the soil in a cattle-farming system with live fences (CFSLF) of Gliricidia sepium and to compare the levels with those of a cattle-farming system based on a grass monoculture (CFSGM). The methodology included a forest inventory in nine randomly assigned plots and the destructive sampling of G. sepium 32 trees, measuring for each tree the diameter at breast height (DBH), stem height, total tree height, branch weight, leaf weight and coarse root weight. In addition, we measured grass biomass, collected litterfall and collected soil samples at depths of 0–10, 10–20 and 20–30 cm in the plots. A logarithmic model was developed to quantify the above- and below-ground tree biomass. The soil organic matter was determined by the dry combustion method. The total carbon stored in the CFSLF was 119.82 Mg C ha −1 , with the G. sepium trees contributing 5.7 % of the total C (6.48 Mg C ha −1 ). The CFSGM stored 113.34 Mg C ha −1 . The grass biomass stored 15.32 Mg C ha −1  year −1 in the CFSGM and 15.68 Mg C ha −1  year −1 in the CFSLF, and the litterfall in the CFSLF stored 0.205 Mg C ha −1  year −1 . Despite the modest contribution of G. sepium trees to the C storage, the total carbon accumulated in the CFSLF and CFSGM was similar.

Description: As part of a broader pattern of recovery after decline called forest transition, tree cover and carbon stocks have increased through agroforestry systems in many parts of Indonesia. The associated tree diversity transition implies that only the most useful parts of local tree flora are promoted. Swampland jelutong, Dyera polyphylla , has been domesticated in peat areas Jambi province, Indonesia. We discuss jelutong domestication in two coastal districts, referring to seven steps in a gradual change from products collected from communal natural forests to specific genotypes managed on private farms. Domestication of D. polyphylla in Jambi was in the initial stages three decades ago, when jelutong latex was directly tapped from the trees in its natural habitat of peat swamp forests. Tapping jelutong latex stopped in 2005 following the national regulation taxing forest products. Some farmers then started jelutong cultivation, motivated by the profitability of trading jelutong latex in the past. Our on-farm study showed that jelutong can be planted in various mixed agroforestry systems, with rubber, coffee or oil palm as dominants. Planted jelutong with good farm management showed diameter growth rates of 1.3 to 1.9 cm year −1 . On-farm trials showed that dolomite as soil ameliorant did not affect diameter growth, but had some effect on height. Jelutong planted between young oil palm had the best performance, while jelutong that was underplanted in mature rubber gardens grew slowly. Slow market revival currently constrains further tree domestication of jelutong.

Description: Hedgerow intercropping provides an efficient method of controlling soil erosion and improving soil fertility on sloping agricultural land. Topsoil (0–20 cm soil layer) of 32 plots established in the Three Gorges Reservoir Area of the Yangtze River was sampled from the steep land between hedgerows (P1) and within hedgerows uphill (P2), under (P3) and downhill (P4) from the hedgerow were analyzed and the soil volumetric fractal dimension (DV) was calculated and the relationships between DV and soil physicochemical properties were tested. Results show that hedgerows effectively intercept clay particles in soil; the soil clay concentration within hedgerows was significantly higher ( P  〈 0.05) than that of the soil between hedgerows at P1, respectively. The soil DV varied significantly among different positions in hedgerow systems, the DV of soil within hedgerows at P2, P3 and P4 were significantly higher ( P  〈 0.05) than that of the soil between hedgerows at P1. DV was correlated positively and very significantly ( P  〈 0.01) with the soil clay concentration ( R 2  = 0.93) and silt content ( R 2  = 0.74), and the DV was significantly ( P  〈 0.01) and negatively correlated with soil sand content ( R 2  = 0.78). The DV was significantly correlated with various soil physical properties and concentrations of soil nutrients. Therefore, the DV can be considered as a potential and accurate evaluating indicator for soil quality and nutrient conservation as they relate to the hedgerow intercropping on steep land.

Description: The diversity of cultivated plants in the agroforestry systems can create conditions to maintain the vital edaphic processes similar to natural regeneration areas. We studied agroforestry systems with five (AF5) and ten years (AF10) of age in comparison with natural regeneration areas for 10 years (NR) in the Atlantic Forest Biome in an area of environmental fragility. The microbial biomass carbon (MB-C), soil basal respiration (BResp), metabolic quotient ( q -CO 2 ) and microbial quotient ( q -mic) were evaluated in the entire profile of a Typic Udorthents, obtaining stratified data in the 0–2.5; 2.5–5; 5–10; 10–15; 15–30; 30–45 and 45–60 cm layers. The NR area had the highest MB-C (866 mg C kg −1 soil) and BResp (5 mg C-CO 2 kg −1 soil h −1 ) in the 0–2.5 cm layer in relation to the AF5 (686 mg C kg −1 soil; 4 mg C-CO 2 kg −1 soil h −1 ) and AF10 (478 mg C kg −1 soil; 4 mg C-CO 2 kg −1 soil h −1 ). However, the ratios did not differ among treatments, presenting average values in the profile of 7 mg C-CO 2 g −1 MB-C h −1 for q -CO 2 and 1.6 % for q -mic, demonstrating vital process similarity between systems. The phytosociological characteristics that interfere with the microbiological attributes were the plant species richness (0–2.5 cm) and plant diversity (2.5–5 cm). The epiedaphic fauna active in the litter was also assessed by pitfall traps and the average number of individuals per trap (238 for NR, 281 for AF5, 299 for AF10), the order richness (15 for NR; 14 for AF5, 13 for AF10) and relative frequencies did not differ among treatments, confirming that agroforests are in an ecosystem self-regulation condition function similar to natural regeneration, even with the removal of food products and income generation for the farmers.

Description: Dendrometric parameters such as tree DBH, height, crown diameter and size characteristics of leaves and fruit production collected from Vitellaria paradoxa subsp. growing in three land use types in Pendjari Biosphere Reserve (PBR) were analyzed. A total of 36 circular plots of 15 m diameter were randomly set in the three main land use sites of the PBR. Thus, Shea butter production was estimated from 90 trees (30 trees in each site) selected randomly. Our results revealed a significant difference in trees traits which increase from the park and hunting zone to the farmlands. The highest production of the selected Shea trees was reported from the farmland. Thus, there is high variability between leaf sizes of trees within the sites while for the fruits the greatest variability is between fruits from same tree. The findings of this study showed that the morphological traits and the production of Shea butter trees could be affected by land use systems.

Description: The introduction of trees in cropland may be a way to improve the mineral nitrogen (N) use efficiency since tree roots can intercept N leached below the crop rooting zone and recycle it as organic N. The aim of this study was to determine soil mineral N (SMN) and total N (STN) contents after 14 years of hybrid walnut tree growth in an agroforestry system. Soil cores were collected and analyses in mid-autumn 2009, in intercropped agroforestry (AF), pure tree (FC) and sole crop control (CC) plots. The SMN was significantly reduced in AF compared to CC (64, 58 and 51 % of reduction at 0.2, 1 and 2 m depth respectively). In the top 1 m of soil, the stock of SMN was 77.7 kg N ha −1 in CC versus 32.8 kg N ha −1 in AF. Trees in AF developed deeper fine roots than in FC, likely involved in the reduction of SMN when compared to CC. Despite this quantitative reduction, trees also progressively modified the form of mineral N in soil by decreasing the percentage of nitrate (NO 3 − ) in SMN, particularly in FC compared to CC, while AF was intermediate. The STN was not significantly different between AF and CC; but was higher in FC in the top soil, probably due to weeds and superficial tree root biomasses. Our results suggest that the introduction of hybrid walnut trees into cropland may be an efficient practice to reduce the potentially leachable N by winter rainfall.

Description: The aim of this study was to relate tree planting spatial arrangements of five eucalypt clones in silvopastoral systems to brachiaria production. Tree layouts were (2 × 2) + 10 m and (3 × 3) + 9 m (double-rows) and 9 × 3 m (single-row) planting arrangements. Tree leaf area index (LAI) was measured acrosss the interrow at 38, 50, and 62 months after planting. Tree crown radius was measured at 45° intervals around the stem at 38 months. Brachiaria was sampled across the interrow at 50 months. The LAI decreased with tree density for most clones and ages. The clones GG100, 58, and 62 presented the lowest LAI, independently of age and planting arrangements. LAI decreased from the tree row to the middle of the interrow, mainly for the double-row arrangements. There was positive correlation between crown radius and area per tree, except for the clone 02, and negative with LAI for the clone 19. The highest brachiaria production was obtained in the arrangements 9 × 3 m (clones GG100 and 62) and (3 × 3) + 9 m (clone 62). Brachiaria production varied across the interrow for clone 58 in the (2 × 2) + 10 m arrangement and for the clone 62 in the double-row arrangements. LAI was not significantly correlated with brachiaria production for the tree planting spatial arrangements and the genotypes studied. Further studies should include larger distances between hedgerows to allow greater resources availability differences across the interrow.