Alternatives to slash-and-burn agriculture: a research approach for the development of a chop-and-mulch system.

The introduction of research-based innovations into traditional land-use systems is difficult, as examples from agroforestry have ShOWD.It can take years to decades until a new agricultural practice has been adopted by the farmers and often the innovations are not very well aligned with the problems and concems of the farmers. Therefore, in our search for altematives to the traditional slash-and-bum land preparation (in the context of the SHIFT project "Secondary forests and fallow vegetation in the agricultural landscape ofthe Eastern Amazon region") we opted for field experiments carried out on small-farmers' land in an old agricultural landscape of the Amazon region. To achieve our objective we follow a phased plan: (i) exploratory research (ii) technology development and prototype evaluation and (iii) adoption-oriented research. During the exploratory project phase we identified the critical needs for improvement, focusing on nutrient dynamics, fallow regeneration, and the replacement of buming during land preparation. Then, instead of designing a completely new land-use system, we aimed at modifying those components of the traditional system which cause degradation processes due to intensified land use or introducing new components which have the potential to prevent these. Alternative technologies were developed as a set of modules including the development of a tractor-driven bush chopper for fire-free land clearing and mulching, enrichment planting with fast-growing leguminous trees to improve the biomass production of the fallow vegetation, shifts in the cropping sequence as well as the screening of modem low-input crop varieties under mulch conditions. Adoption of these modules is flexible, leaving the farmer in control of the innovation processo The adoption-oriented research phase is currently underway and assesses the willingness of the farmers to adopt the farming system improvements. Participatory on-farm research facilitates the adoption process

A research concept for the development of alternatives to slash-and-burn agriculture in the Eastern Amazon region.

Editado por Reinhard Lieberei, Helmut Bianchi, Vera Boehm, Christoph Reisdorff

Mechanized land preparation in forest-based fallow systems: the experience from eastern Amazonia.

The slash-and-burn practice of land preparation that farmers use traditionally in forest-based fallow systems in the humid tropics causes land degradation and human health hazards. As an alternative to slash-and-burn, a mechanized, fire-free method of land preparation was evaluated on smallholdings in the eastern Amazon region. The use of machinery for harvesting fallow vegetation and chopping it for mulch eliminates the need for hard labor and fire for land clearing and increases labor productivity. Four different tractor-propelled choppers with power demand of 50 kW to 122 kW were tested. Their chopping capacity varied between 4.5 Mg and 20 Mg of fresh biomass per hour. The mechanized chop-and-mulch technology can be used in fallow vegetation that is up to 12 years old, which in the study region corresponded to 20 Mg to 150 Mg fresh biomass per hectare. Two additional choppers ? a stationary silage chopper and a high-powered crawler tractor with a chopping device ? were also tested but both were not suitable for smallholder fallow systems. In the context of the mulch technology, new low-input crop varieties were screened and their response to fertilizer was studied. The mulch technology facilitates extended cropping, to plant crops off-season, and modify crop rotation. Degraded fallow vegetation can be improved by enrichment planting using fast-growing leguminous tree species. Financial analysis of different scenarios revealed that farm income and labor productivity from chop-and-mulch systems can be up to two times greater than from the traditional slash-and-burn system

The Testing by Fire of the Builders' Works: 1 Corinthians 3.10-15

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Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis

Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base

Over-expression of adenosine deaminase in mouse podocytes does not reverse puromycin aminonucleoside resistance

<p>Abstract</p> <p>Background</p> <p>Edema in nephrotic syndrome results from renal retention of sodium and alteration of the permeability properties of capillaries. Nephrotic syndrome induced by puromycin aminonucleoside (PAN) in rats reproduces the biological and clinical signs of the human disease, and has been widely used to identify the cellular mechanisms of sodium retention. Unfortunately, mice do not develop nephrotic syndrome in response to PAN, and we still lack a good mouse model of the disease in which the genetic tools necessary for further characterizing the pathophysiological pathway could be used. Mouse resistance to PAN has been attributed to a defect in glomerular adenosine deaminase (ADA), which metabolizes PAN. We therefore attempted to develop a mouse line sensitive to PAN through induction of normal adenosine metabolism in their podocytes.</p> <p>Methods</p> <p>A mouse line expressing functional ADA under the control of the podocyte-specific podocin promoter was generated by transgenesis. The effect of PAN on urinary excretion of sodium and proteins was compared in rats and in mice over-expressing ADA and in littermates.</p> <p>Results</p> <p>We confirmed that expression of ADA mRNAs was much lower in wild type mouse than in rat glomerulus. Transgenic mice expressed ADA specifically in the glomerulus, and their ADA activity was of the same order of magnitude as in rats. Nonetheless, ADA transgenic mice remained insensitive to PAN treatment in terms of both proteinuria and sodium retention.</p> <p>Conclusions</p> <p>Along with previous results, this study shows that adenosine deaminase is necessary but not sufficient to confer PAN sensitivity to podocytes. ADA transgenic mice could be used as a background strain for further transgenesis.</p