-A winter wheat (cv Soissons) crop was made N deficient during stem elongation. The effects of the N stress were quantified by measuring the nitrogen nutrition index (NNI) (used as reference), proteolytic activity in the leaves, the rate of carbon dioxide (CO 2 )
In a precision farming context, differentiated management decisions regarding fertilization, application of lime and other cultivation activities may require the subdivision of the field into homogeneous regions with respect to the soil variables of main agronomic significance. The paper develops an approach that is aimed at delineating homogeneous regions on the basis of measurements of a categorical and quantitative nature, namely soil type and resistivity measurements at different soil layers. We propose a Bayesian multivariate spatial model and embed it in a Markov chain Monte Carlo inference scheme. Implementation is discussed using real data from a 15-ha field. Although applied to soil data, this model could be relevant in areas of spatial modelling as diverse as epidemiology, ecology or meteorology. Copyright 2006 Royal Statistical Society.
The anthesis-to-maturity period is a deciding phase in end wheat-yield because it corresponds to rormation and filling of the grains. An experimental approach showed that it was possible to estimate an agronomical variable (EWC=ear water concentration) related to phenological development from multidate radiometric data in the SPOT bands.We round that a combination of spectral bands such as NDVI (normalised diflerence vegetation index) allows EWC to be estimated through time (r2 =0.90 and confidence interval = k5.2 per cent).Thus, it is possible to monitor the wheat developmental stage after anthesis and to detect precisely the end of grain filling.Rbsumb. La ptriodc floraison-maturite est determinante pour le rendement final du ble parce qu'elle correspond a la mise en place et au remplissage des grains. Une demarche experimentale a montrk qu'il etait possible d'estimer une variable agronornique (EWC=taux d'humidite de I'epi) representative du stade de developpement a partir de donnees radiometriques multidates dans les bandes SPOT.Nous avons trouve qu'une combinaison de bandes spectrales, la diflerence normalisee (NDVI), permet d'estimer EWC au cours du temps (r2=0.90 et intervalle de confiance = 5.2 pour cent).Ainsi, il est possible de contrder le stade de developpernent du blt a partir de la Roraison et de detecter precisement la fin du remplissage des grains.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.