State of apps targeting management for sustainability of agricultural landscapes. A review

International audienceAbstractThe triple-bottom-line approach to sustainability in agriculture requires multi- and inter-disciplinary expertise and remains a major design and implementation challenge. Tools are needed to link extension agents, development workers, farmers, and other agriculture decision-makers to information related to practices that improve sustainability across agricultural landscapes. The digital age has brought many new cloud-based and mobile device–accessible software applications (apps) targeted at farmers and others in the agriculture sector; however, the effectiveness of these tools for advancing sustainability goals is unknown. Here, we review apps for agriculture in order to identify gaps in information provisioning and sharing for tools that connect decision-makers to knowledge in support of sustainable agricultural landscapes. The major findings are (1) Agricultural apps can be categorized as supporting regulatory compliance, equipment optimization, farming simulator games, information management, agronomic reference information, product tracking, pest identification, emissions accounting, or benchmarks for marketing claims. (2) Many apps are developed to link specific products for single solutions, such as GPS-guided crop implementation or sensors within Internet-of-things connectivity. (3) While pilots, prototypes, and case studies are available in both Apple and Android digital markets, public mobile apps to improve multidirectional agriculture knowledge exchange are limited and poorly documented. (4) There remains a need for apps emphasizing knowledge exchange and resource discovery, rather than simply information delivery, to help farmers identify evidence-based practices that improve indicators of sustainability. (5) Development of a digital decision support tool requires early and ongoing interactions with targeted end users to clarify app performance objectives and social networking preferences, ensure reliability of scientific input and business management plans, and optimize the user experience

Forage Performance and Soil Quality in Forage Systems under Organic Management in the Southeastern United States

aBstract Interest is increasing in organic forage production and sod-based rotations in the southeastern United States, but research-based information is limited. A replicated fi eld study was established to evaluate productivity and soil quality changes in fi ve organicallymanaged forage systems over 2 yr. Systems included four regionally-adapted perennial systems and one warm-and cool-season annual rotation: (i) alfalfa (Medicago sativa L.), (ii) red clover (Trifolium pratense L.), (iii) alfalfa/orchardgrass (Dactylis glomerata L.), (iv) red clover/orchardgrass, and (v) an annual system of wheat (Triticum aestivum L.)/crimson clover (T. incarnatum L.) followed by sorghum-sudangrass [Sorghum bicolor × S. bicolor var. sudanense (Piper) Stapf.]. Soil quality was compared to two annual vegetable systems, one managed organically and one managed conventionally. Poultry litter was applied to organically-managed systems in September 2010 (9 Mg ha -1 ) and in September 2011 (4.5 Mg ha -1 ). Mean annual forage yield was greatest from wheat/crimson clover and sorghum-sudangrass (12.4 Mg ha -1 yr -1 ), intermediate from red clover, red clover/orchardgrass, and alfalfa/orchardgrass (10.0-10.3 Mg ha -1 yr -1 ), and least from alfalfa (7.6 Mg ha -1 yr -1 ). Soil C (total and particulate organic matter-C) increased over 2 yr in all forage systems which were similar, and was in most cases signifi cantly lower in vegetable systems. Soil N (total and particulate organic matter-N) increased in all forage systems and was highest in alfalfa and treatments containing red clover, and lowest in vegetable systems. Results suggest these short-term forage systems are viable options for regional organic rotations

A Specialized Outer Layer of the Primary Cell Wall Joins Elongating Cotton Fibers into Tissue-Like Bundles1[W][OA]

Cotton (Gossypium hirsutum) provides the world's dominant renewable textile fiber, and cotton fiber is valued as a research model because of its extensive elongation and secondary wall thickening. Previously, it was assumed that fibers elongated as individual cells. In contrast, observation by cryo-field emission-scanning electron microscopy of cotton fibers developing in situ within the boll demonstrated that fibers elongate within tissue-like bundles. These bundles were entrained by twisting fiber tips and consolidated by adhesion of a cotton fiber middle lamella (CFML). The fiber bundles consolidated via the CFML ultimately formed a packet of fiber around each seed, which helps explain how thousands of cotton fibers achieve their great length within a confined space. The cell wall nature of the CFML was characterized using transmission electron microscopy, including polymer epitope labeling. Toward the end of elongation, up-regulation occurred in gene expression and enzyme activities related to cell wall hydrolysis, and targeted breakdown of the CFML restored fiber individuality. At the same time, losses occurred in certain cell wall polymer epitopes (as revealed by comprehensive microarray polymer profiling) and sugars within noncellulosic matrix components (as revealed by gas chromatography-mass spectrometry analysis of derivatized neutral and acidic glycosyl residues). Broadly, these data show that adhesion modulated by an outer layer of the primary wall can coordinate the extensive growth of a large group of cells and illustrate dynamic changes in primary wall structure and composition occurring during the differentiation of one cell type that spends only part of its life as a tissue