On the Economics of Precision Agriculture: Technical, Informational and Environmental Aspects

The paper presents an integrated framework of biophysical and economic modelling as a novel approach towards precision agriculture research. A theoretical economic model determining the optimal number of precision agriculture management units within a given field of land is presented. The model is expanded to account for the value of the research information provided be the precision agriculture researchers. Since the inherent environmental values associated with precision agriculture are often omitted from the economic analysis, an attempt is made to incorporate these values into the model. The versions of the model are empirically tested using the data available.economics, precision agriculture, environment, information, Agribusiness, Environmental Economics and Policy,

GlobalSoilMap.net - From planning, development and proof of concept to full-scale production mapping

The GlobalSoilMap.net project aims to produce predictions of nine key soil properties at continuous depth intervals at a spatial resolution of 90 m for the entire world. These maps of soil properties will be produced by a participants working under the coordination of regional node leaders with responsibility for organizing and delivering results for eight defined geographic regions of the world. This paper identifies and discusses the technical impediments to moving towards commencement of operational production mapping. These are: i) agreement on specifications for all products, ii) location, digital capture and harmonization of legacy soil data, iii) assembly of covariate databases, iv) documentation of prediction methods, v) specification of data model(s) to use to capture, store and disseminate maps and data, vi) selection of cyber-infrastructure to support map production and dissemination vii) end user surveys assessment and verification, and vii) identification of methods for assessing the uncertainty and accuracy of predictions. Actions undertaken to date to address these challenges are presented and progress is evaluated. There are no significant technical reasons for not moving towards planning and implementing operational production mapping

Inverse meta-modelling to estimate soil available water capacity at high spatial resolution across a farm

Geo-referenced information on crop production that is both spatially- and temporally-dense would be useful for management in precision agriculture (PA). Crop yield monitors provide spatially but not temporally dense information. Crop growth simulation modelling can provide temporal density, but traditionally fail on the spatial issue. The research described was motivated by the challenge of satisfying both the spatial and temporal data needs of PA. The methods presented depart from current crop modelling within PA by introducing meta-modelling in combination with inverse modelling to estimate site-specific soil properties. The soil properties are used to predict spatially- and temporally-dense crop yields. An inverse meta-model was derived from the agricultural production simulator (APSIM) using neural networks to estimate soil available water capacity (AWC) from available yield data. Maps of AWC with a resolution of 10 m were produced across a dryland grain farm in Australia. For certain years and fields, the estimates were useful for yield prediction with APSIM and multiple regression, whereas for others the results were disappointing. The estimates contain ‘implicit information’ about climate interactions with soil, crop and landscape that needs to be identified. Improvement of the meta-model with more AWC scenarios, more years of yield data, inclusion of additional variables and accounting for uncertainty are discussed. We concluded that it is worthwhile to pursue this approach as an efficient way of extracting soil physical information that exists within crop yield maps to create spatially- and temporally-dense dataset

India's "Hundred Voices" : Subaltern oral performance in Forster's A passage to India

I wish to argue that oral theory and contemporary critical theory not only share similar "principles," "issues," and "questions," but may profitably inform each other under these shared headings. As a newcomer to oral studies, I would be presumptuous to say how critical theory might contribute to the development and refinement of oral theory. However, as a student of colonial literature, I see clear ways in which oral theory might enable the practice of one kind of critical theory--that is, colonial/postcolonial theory: how it might help define its terms, shape its lines of inquiry, sharpen its methodology, and, most important, engage with other kinds of theory in useful crossdisciplinary work.Not

Interplant competition among oat and barley varieties and isolines

Four experiments were grown to evaluate competitive abilities of plant genotypes. The materials consisted of a set of early and a set of midseason oat (Avena sativa L.) isolines, a set of oat varieties, and a set with two barley (Hordeum vulgare L.) and three oat varieties. Plants of one genotype were sown in the center of each of paired hexagon plots with the tester plant which was grown in the center being surrounded by two rows of plants consisting of its own genotype in one plot and of another genotype in the paired plot;The oat isolines showed some evidence for overcompensation, whereas the oat varieties and oat and barley varieties were neutral with respect to competitive ability. Entries within a set were highly variable with respect to mean competitive reactions. The effects of competition were even more variable when individual pairs were compared. In the sets where isolines were grown, a large mean deviation for one entry most often was caused by an exceptionally large competitive advantage or disadvantage that occurred for only one paired comparison. When barley and oats were grown together in competitive stands, the competitive advantage or disadvantage shown by an entry tended to be consistent across all competitors;Competitive advantages or disadvantages displayed by oat and barley genotypes for biomass and grain yield were related to biomass or grain yield components. Increases in biomass and grain yield were reflected in significant increases in numbers of spikelets, primary and secondary florets, and tillers per plant. Competitive advantages and disadvantages were greatest in the interspecific comparisons