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Aiming at the increase of carbon dioxide concentration in the atmosphere, the difficulty of carbon sink measurement in farmland ecosystem and the lack of basis of grain carbon subsidy, this paper focuses on the problem that wheat conducts photosynthesis through light radiation to absorb carbon dioxide in the atmosphere and soil. And the wheat's photosynthetic carbon model was constructed using experiment...
Synthetic aperture radar (SAR) has shown promising results in characterizing different crops. Multi-temporal SAR data is often useful for studying the sensitivity of the electromagnetic (EM) waves to the structural and the dielectric variation of both crops and the underlying soil at different phenological stages. Physical information about crops and soil can be interpreted in terms of scattering...
A lodged wheat detection algorithm by applying a false alarm rate to the circular-pol correlation coefficient (CCC) and the total scattered power (Span) is proposed. The CCC is first used to identify non-lodged wheat, which is reflection symmetry. The Span feature is introduced to distinguish lodged wheat from canola in the study area, according to their large difference in scattering intensity. The...
Production of high quality wheat has a great importance especially in the solution of nutrition problems. It is necessary to make decomposition for specifying the quality. Here, high quality and unclassified wheat recognition are realized. The most distinctive feature between high quality and poor quality wheat is the shape difference. In this study, Bag of Contour Fragments (BCF) was used as a shape...
For the purpose of rapid, simple and accurate identification of quality of wheat grains, this study proposed a recognition method which is an integration of near infrared spectroscopy and support vector machine (SVM). The spectral data of wheat samples were analyzed in order to eliminate abnormal data, and then Mahalanobis distance method was used to identify abnormal samples. After deleting those...
The upgrade rate of self-sufficiency in wheat depends largely on the amount of water and land to achieve the quantity and proportion of self-sufficiency target. The climatic and soil conditions, however, are dynamic conditions. Hence, these conditions seriously limit the capability of providing the optimum tempo-spatial required data to assist in improving the wheat production unless specialized sensors...
It is quite confusing to effectively monitor and precisely evaluate growing conditions of wheat by using normalized differential vegetation index based on pixel size (NDVIp) as they are significantly different when acquired by the wheat of same growth status with different types of soil background. The wheat canopy normalized differential vegetation index(NDVIc) acquired by one scene of multi-spectral...
Chlorophyll fluorescence (CF) is a direct indicator of plant physiology and reflects the photochemical process and its efficiency. CF is difficult to quantify because it is included in the reflected light. In the present study, the interrelationships between chlorophyll fluorescence parameters and spectral reflectance measured in the first, second, third and fourth leaves from the top of plant from...
The accurate prediction of crop yield is of great importance to regional production and food security. Many empirical models for crop production prediction are based on vegetation indices (VI) such as normalized vegetation index (NDVI) or simple ratio (SR) in specific growing period, with little attention paid to the sensitivity of different growing stages to yield prediction. This study investigates...
This study proposes a simple empirical model based on polarimetric parameters extracted from RADARSAT-2 imagery to retrieve surface soil moisture (0–5 cm) over agricultural fields. The model is calibrated with ground data acquired from 13 wheat fields, over their whole growth cycle, during the SMAPVEX12 campaign. Sensitivity analysis of the extracted polarimetric variables to soil moisture demonstrated...
The dust stress of wheat leaves were diagnosed with hyperspectral technology. A four-level dust stress (i.e. severe, moderate mild stress and normal status) experiment was conducted using the wheat in growing season as the study object. The spectra of wheat leave which treated with different stress intensity levels were collected by AvaSpec-2048×14-USB2 Spectrometer, and 32 samples were obtained for...
The assimilation of biophysical crop canopy variables retrieved from remotely sensed data into two crop models of differing degree of complexity is assessed in this study, in the context of the development of tools suitable for the estimation of yield losses due to drought. The more complex AQUACROP model, developed by FAO and the simpler SAFY model were employed to estimate wheat grain yield for...
Leaf area index (LAI) is very used to reveal the vegetation situation. To estimate the LAI for cereal, both direct and indirect methods have been used. In particular, remote sensing is a fast and reliable technique to develop the LAI estimation models. In this work, we present the potential of Sentinel 1 images for cereal estimation LAI in the center of Tunisia under semi arid climate. We established...
Spectral data have been widely used to estimate the disease severity $(\mathbf{DS})$ levels of different plants. However, such data have not been evaluated to estimate the disease stages of the plant. This study aimed at developing a spectral disease index (SDI) that is able to identify the stages of wheat leaf rust disease at various $\mathbf{DS}$ levels. To meet the aim of the study, the reflectance...
Cereals have a prominent place in food self-sufficiency. This crop is the main source of human and animal nutrition in the world. Therefore, monitoring the cereal production in order to manage agricultural practices such as the crop yield forecasting, the identification of the risk of diseases and the application of fertilizers is essential. Several techniques are used for agricultural yield estimation;...
MicroRNAs (miRNAs) are the key modulators implicated in the regulation of virtually every biological process found in multicellular eukaryotes. Wheat (Triticum aestivum) is one of the most important cereal crops worldwide. To date, only a few conserved miRNAs have been reported in wheat and their association with different metabolic process is still in dark. Therefore, the present study we attempt...
The research made an adaptation for Michigan Microwave Canopy Scattering (MIMICS) model at four bands (L, S, C, X) after taking wheat ears as the first layer. When wheat ears appears in heading stage, they locate on the top of the whole wheat and owes the different dielectric constant and water content, which should be considered the important scattering elements. The scattering character of wheat...
Wheat (Triticum aestivum L.) is the major crop of Pakistan's being 9th largest wheat producer country. Unfortunately, wheat crop is always under attack by diseases in which 100 diseases are caused by pathogens and others are due to weeds and different parasites. Mostly rust diseases are air-borne and soil-borne. Foliar rust diseases; yellow/stripe rust, brown/leaf rust, powdery mildew and tan spot...
Fusarium head blight (FHB) limits wheat yield and compromises grain quality. We investigated differentially expressed genes after FHB challenge. FHB-susceptible and -resistant common wheat (Triticum aestivum) cultivars were challenged with the toxigenic fungus Fusarium graminearum and gene expression was analyzed using 61K Affymetrix wheat microarrays. We digitized trait specificity in the susceptible...
The objective of this work is to assess the retrieval of above ground dry biomass (ABG) of wheat fields from dual polarized X- and C-band SAR data. A linear regression between the ratio of cross- and co-polarized backscatter (i.e. PQ/PP) and AGB measured during three past (i.e. the TerraSARSIM'03, AgriSAR'06, COSMOLAND'10–11) and one ongoing campaign over the Apulian Tavoliere has been sought and...
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