vegetation index Articles
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A simple spectral index using reflectance of 735 nm to assess nitrogen status of rice canopy
Spatial distribution of canopy N status is the primary information needed for precision management of N fertilizer. This study demonstrated the feasibility of a simple spectral index (SI) using the first derivative of canopy reflectance spectrum at 735 nm (dR/d|735) to assess N concentration of rice (Oryza sativa L.) plants, and then validated the applicability of a simplified imaging system ...
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Spatial analysis of early wheat canopy normalized difference vegetative index
Efficient use of real-time canopy sensors requires knowledge of the scale (resolution) of variation in the measured canopy property. Knowing the amount of needed optical data requires estimation of the optimal combination of physical sensor density (number of sensors along the applicator boom) and sensor output density (sensor readings per unit distance along the travel path). The objective of ...
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Peanut response to planting date and potential of canopy reflectance as an indicator of pod maturation
Determining when to dig peanut (Arachis hypogea L.) is complicated because of its indeterminate growth habit. Pod mesocarp color is often used an indicator of pod maturation. However, this process is time consuming and is usually based on a relatively small subsample of pods from peanut fields. Research was conducted during 2003–2005 to determine if reflectance of the peanut canopy, using ...
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Nondestructive measurement of grapevine leaf area by ground normalized difference vegetation index
Vine leaf area index has a great impact on berry quality. This study was conducted to determine whether vine leaf area index could be estimated, and mapped through normalized difference vegetation index (NDVI) ground-based measurements. The NDVI measurements were performed using a Greenseeker (N-Tech Industires, Ukiah, CA and Oklahoma State Univ., Stillwater), pointed sideways at the vertical ...
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Spatial analysis of early wheat canopy normalized difference vegetative index: determining appropriate observation scale
Efficient use of real-time canopy sensors requires knowledge of the scale (resolution) of variation in the measured canopy property. Knowing the amount of needed optical data requires estimation of the optimal combination of physical sensor density (number of sensors along the applicator boom) and sensor output density (sensor readings per unit distance along the travel path). The objective of ...
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Evaluating multiple indices from a canopy reflectance sensor to estimate corn n requirements
With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn (Zea mays L.). The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N requirements for corn, and (ii) to consider the influence of the N:Corn price ratio ...
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Nitrogen recommendations for corn: An on-the-go sensor compared with current recommendation methods
Precision agriculture technologies provide the capability to spatially vary N fertilizer applied to corn (Zea mays L.), potentially improving N use efficiency. The focus of this study was to evaluate the potential of improving N recommendations based on crop canopy reflectance. Corn was grown at four field sites in each of 2 yr in Centre County, Pennsylvania. Preplant treatments included: zero ...
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Estimating ground cover of field crops using medium-resolution multispectral satellite imagery
Remote sensing is useful for estimating plant canopy characteristics, such as leaf area index (LAI) and ground cover (GC). When the source of remote sensing data is medium-resolution satellite imagery, plant canopy characteristics can be estimated for numerous fields within an agricultural region. In this study, a procedure was developed to estimate GC of field crops from medium-resolution ...
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Drones and scissors help decide fertilizer rate
Both Swedish and European field trials show that winter oilseed rape that has taken up a lot of nitrogen in autumn needs less nitrogen in the spring. A thinner crop, which has not assimilated so much nitrogen in the autumn, needs more N fertilizer in the spring. In order to determine the autumn’s nitrogen uptake, the so-called “cutting method” is often used in Sweden. Drones ...
By Solvi AB
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Variable Rate Seeding with Drone Imagery
Getting a good crop canopy across the entire field is important for better crop quality and higher yield. One way of achieving this is by varying the amount of seeds. In recent years more and more farmers have started using variable-rate technology. By coupling the tractor’s GPS equipment with the seed drill, the seed amount can be varied across the field based on a predetermined plan. The ...
By Solvi AB
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Better nitrogen application in winter wheat with drones
There’s no doubt that spring is one of the busiest times of the year for farmers and agronomists. Activities carried out during spring make foundation for the whole season and have crucial impact on quality and quantity of yields. Nitrogen application is one of the key actions that growers take to ensure stable crop development. When winter crops enter the stroke phase, the absorption of ...
By Solvi AB
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Farmonaut For Crop Area and Yield Estimation
INTRODUCTION: CROP AREA ESTIMATION The two components of agricultural production estimation are crop area and yield estimation. In order to estimate yield, Producers generally measure the amount of a particular crop harvested in a sample area to estimate crop yield. The harvested crop is then weighed, and the entire crop production of the area is approximated from the sample. A method for ...
By Farmonaut
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The Power of Fusing 3D with Multispec
3D assessment of plants became a commonly used technology in plant phenotyping to measure morphological and architectural features of plants. Although, 3D sensors such as PlantEye can be the workhorse for every phenotyping platform, it still lacks the ability to measure changes in color or other spectral information that are an important indicator for the plants physiological ...
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