ALBERT

Description: Human activity has a greater influence on plants than on any of the other components of the environment. We used material from cultivated and wild Coptis teeta populations in the Hengduan Mountains to test the null hypothesis that there is no effect of human activity on the biomass allocation of an herbaceous understory species in a forest ecosystem. At the plot level, an isometric relationship existed in most of the significant relationships. However, at the individual level, an allometric relationship existed in most of the log–log relationships. Human activity could significantly affect the slope of the linear relationship of leaf versus total biomass; and also the intercepts of the relationships of root biomass versus total biomass, plant height versus total biomass and reproductive versus vegetative biomass. At any given plant body size, wild C. teeta has higher biomass in the leaf and less in root than cultivated counterpart. But the trajectories of log rhizome biomass versus log total biomass were the same for both cultivated and wild individuals. Thus, we conclude that (1) the allometric trajectories change at different scales and (2) C. teeta -based agroforestry system could ensure sustainable use of this medicinal plant because of the stable biomass allocation to the salable rhizome organs.

Description: A pressing challenge facing poor farmers is how to maintain yields in swidden-fallow systems when confronting growing land scarcity and declining soil fertility. The objective of this research is to document the innovative use of biochar and biochar-rich kiln soils on charcoal kiln sites by Amazonian peasant farmers for annual and perennial crop production as part of their swidden-fallow agroforestry cycle. The study was undertaken in a riverside community near Iquitos, Peru, where the availability of primary forest land has decreased significantly over the past 30 years. Charcoal production is a long-standing, near ubiquitous local activity, drawing on wood primarily from secondary forest fallows. Data were collected in 2011 through household interviews (n = 36) and an extensive survey of upland kiln sites (n = 500). Results indicate this innovation, dubbed “kiln site agriculture” (KSA), evolved endogenously within the study community as an adaptation to growing land scarcity. Current landholdings were found to negatively correlate with both the number of crops households (n = 32) cultivated per kiln site ( r  = −0.3483, p  = 0.0254) and the proportion of those sites cultivated with manioc, the local staple crop ( r  = −0.5441, p  = 0.0006), suggesting that land-poor households rely on KSA harvests to supplement subsistence. This study provides evidence charcoal production need not be a rapacious forest use and can, through KSA and biochar, offer an affordable opportunity to peasant farmers who practice swidden-fallow agroforestry where new land in primary forest is scarce and the productivity of their weathered soils is falling.

Description: Nanoscience emerged in the late 1980s and is developed and applied in China since the middle of the 1990s. Although nanotechnologies have been less developed in agronomy than other disciplines, due to less investment, nanotechnologies have the potential to improve agricultural production. Here, we review more than 200 reports involving nanoscience in agriculture, livestock, and aquaculture. The major points are as follows: (1) nanotechnologies used for seeds and water improved plant germination, growth, yield, and quality. (2) Nanotechnologies could increase the storage period for vegetables and fruits. (3) For livestock and poultry breeding, nanotechnologies improved animals immunity, oxidation resistance, and production and decreased antibiotic use and manure odor. For instance, the average daily gain of pig increased by 9.9–15.3 %, the ratio of feedstuff to weight decreased by 7.5–10.3 %, and the diarrhea rate decreased by 55.6–66.7 %. (4) Nanotechnologies for water disinfection in fishpond increased water quality and increased yields and survivals of fish and prawn. (5) Nanotechnologies for pesticides increased pesticide performance threefold and reduced cost by 50 %. (6) Nano urea increased the agronomic efficiency of nitrogen fertilization by 44.5 % and the grain yield by 10.2 %, versus normal urea. (7) Nanotechnologies are widely used for rapid detection and diagnosis, notably for clinical examination, food safety testing, and animal epidemic surveillance. (8) Nanotechnologies may also have adverse effects that are so far not well known.

Description: The nematode Radopholus similis is a major pest in banana plantations worldwide. This nematode is actually controlled using synthetic, toxic nematicides. Alternative control methods are therefore needed. For instance the liquid by-product of fiber extraction from sisal ( Agave sisalana ) may be used as a nematicide. Here we tested the nematicidal activity of the sisal residue, fresh or fermented, on R. similis in banana plants. We measured immobility and mortality effects by nematode immersion in an aqueous solution of sisal residue for 24 and 48 h. Nematode control was also evaluated in the Grand Naine banana plants under greenhouse conditions using soil amendments of residues. We measured plant growth, pseudostem diameter, the number of leaves, and the dry weight of the aerial parts, corm and roots, as well as factors related to nematode control such as the level of damage, the population of R. similis in roots and soil, and nematode reproduction factors. Our results show that the sisal residue efficiently controlled R. similis in vitro, displaying mortality rates of 99.2 % for the fresh residue. The damage caused by R. similis on plants was similar for the treatment with the sisal residue at a concentration of 25 % and with the nematicide. This is the first report on the nematicidal effect of the sisal liquid residue on the banana burrowing nematode. This by-product presents the potential for the development of new alternatives for nematode control, with a low-cost and low-environmental risk plant nematicide.

Description: Homegarden agroforestry systems are suggested to hold a large potential for climate change mitigation and adaptation. This is due to their multifunctional role in providing income, food and ecosystem services while decreasing pressure on natural forests and hence saving and storing carbon. In this paper, above-ground biomass carbon and tree species diversity of trees was quantified in homegardens around two villages in the dry south-eastern part of Moneragala district of Sri Lanka. A total of 45 dry zone homegardens were sampled on size, diameter at breast height, tree height and species diversity. Using allometric equations, we find a mean above-ground biomass stock of 13 mega grams of carbon per hectare (Mg C ha −1 ) with a large range among homegardens (1–56 Mg C ha −1 , n  = 45) due to a variation of tree diversity and composition between individual homegardens. Mean above-ground carbon stock per unit area was higher in small homegardens (0.2 ha, 26 Mg C ha −1 , n  = 11) and statistically different compared to medium (0.4–0.8 ha, 9 Mg C ha −1 , n  = 27) and large (1.0–1.2 ha, 8 Mg C ha −1 , n  = 7) homegardens. In total, 4,278 trees were sampled and 70 tree species identified and recorded. The Shannon Wiener index were used to evaluate diversity per homegarden and ranged from 0.76 to 3.01 with a mean value of 2.05 ± 0.07 indicating a medium evenly distributed diversity of sampled tree species. The results show a vast heterogeneity in terms of carbon stock and tree diversity within the less studied dry zone homegardens; results that contribute to more knowledge of their expansion potential as well as climate mitigation and adaptation potential. The results are also useful for whether homegardens should be considered to be included as an activity to enhance natural forest cover within Sri Lanka’s newly commenced UN-REDD National Programme.

Description: Sclerocarya birrea (A. Rich.) Hochst. (marula) is one of the most important indigenous fruit tree species in southern Africa, where it plays a significant role in the diet, tradition and culture of many indigenous people. The species has in the past decade been the subject of domestication to enhance its wider scale cultivation and conservation to preserve its genetic diversity. In this study, we report on the performance of 21 geographic populations of marula (20 of S . birrea ssp. caffra and one of S . birrea ssp. birrea ) planted in Mangochi, Malawi (14°28′S, 35°14’E and 469 m elevation). The trial was assessed for tree height, bole height, root collar diameter (RCD), diameter at breast height (DBH), crown width and depth, and fruiting at 7 years after out-planting. There were significant differences between the populations for most of the traits. Differences between the top and bottom ranked populations were often up to three-fold, reflecting wide genetic variation in the germplasm. The Marracuene population from Mozambique, was ranked top for height, RCD, DBH, crown width and crown depth. Only eight populations had fruits of which Marracuene population had the highest fruit yield. Although the average fruit load per tree ranged from one to 274 among the fruiting populations, tree-to-tree variation in fruit production was very wide ranging from one to 1,228 fruits per tree. Phenotypic correlations among the growth and crown size (height, RCD, DBH and crown depth) traits were large, positive and significant (P 〈 0.001). Correlations between fruit yield and growth and crown size traits although significant and positive, were mostly moderate. The implication of this large genetic variation in growth and fruit production detected among the marula populations is discussed in relation to conservation, breeding and choice of seed source for planting.