نتایج جستجو برای: field crop

تعداد نتایج: 842423  

2018
A. E. Johnston P. R. Poulton

Long-term field experiments that test a range of treatments and are intended to assess the sustainability of crop production, and thus food security, must be managed actively to identify any treatment that is failing to maintain or increase yields. Once identified, carefully considered changes can be made to the treatment or management, and if they are successful yields will change. If suitable...

2015
E. Zillmann M. Schönert H. Lilienthal B. Siegmann T. Jarmer P. Rosso H. Weichelt

Remote sensing is a suitable tool for estimating the spatial variability of crop canopy characteristics, such as canopy chlorophyll content (CCC) and green ground cover (GGC%), which are often used for crop productivity analysis and site-specific crop management. Empirical relationships exist between different vegetation indices (VI) and CCC and GGC% that allow spatial estimation of canopy char...

Journal: :Remote Sensing 2010
Christopher Conrad Sebastian Fritsch Julian Zeidler Gerd Rücker Stefan W. Dech

The overarching goal of this research was to explore accurate methods of mapping irrigated crops, where digital cadastre information is unavailable: (a) Boundary separation by object-oriented image segmentation using very high spatial resolution (2.5–5 m) data was followed by (b) identification of crops and crop rotations by means of phenology, tasselled cap, and rule-based classification using...

2013
Nataliia Kussul Sergii Skakun Oleksii Kravchenko Andrii Shelestov Javier Francisco Gallego Olga Kussul

Crop area estimation is a key element in crop production forecasting and estimation. Satellite imagery can provide valuable information for stratification purposes and can be used as a source of proxy variables for aposteriori correction of area estimates. In this regard, efficiency of crop area estimation using satellite imagery depends on the accuracy of crop classification. In this paper, we...

2017
S. S. Thorat K. V. Kale S. C. Mehrotra Y. D. Rajendra V. B. Waghmare

Estimation of specific crop and acreage plays a vital role in the field of crop planning, monitoring, crop condition, yield forecasting and acreage estimation. There have been several studies conducted to classify the crops at continental to the regional level, but still, work is needed to map small area covered by different crops using Remote Sensing technology. The main objective of the prese...

Journal: :American journal of botany 2001
H M Alexander C L Cummings L Kahn A A Snow

The movement of pollen between crop and wild sunflowers (both Helianthus annuus) has led to concerns about the possible introduction of crop transgenes into wild populations. The persistence of crop traits in wild populations will depend in part on the relative fitness of crop-wild hybrid vs. wild plants. Using seeds from two large experimental field plots, we found that seeds produced by crop-...

Journal: :آب و خاک 0
وحیدرضا وردی نژاد تیمور سهرابی نادر حیدری شهاب عراقی نژاد محمد فیضی

abstract in this study, seven main field crops of the rudasht and abshar irrigation networks of esfahan (with 54,000 ha designed command area) such as wheat, barley, onion, sunflower, fodder mays and sugar beet were selected and swap model was calibrated by inverse modeling base on field experiments results in order to determine crop water salinity production functions. field experiments were c...

2005
V. K. Dadhwal

Crop growth and productivity are determined by a large number of weather, soil and management variables, which vary significantly across space. Remote Sensing (RS) data, acquired repetitively over agricultural land help in identification and mapping of crops and also in assessing crop vigour. As RS data and techniques have improved, the initial efforts that directly related RS-derived vegetatio...

Journal: :Remote Sensing 2014
Jakob Geipel Johanna Link Wilhelm Claupein

Precision Farming (PF) management strategies are commonly based on estimations of within-field yield potential, often derived from remotely-sensed products, e.g., Vegetation Index (VI) maps. These well-established means, however, lack important information, like crop height. Combinations of VI-maps and detailed 3D Crop Surface Models (CSMs) enable advanced methods for crop yield prediction. Thi...

2005
MICHAEL NØRREMARK CLAUS G. SØRENSEN NIELS A. ANDERSEN

A flexible high-level control language is an important element in the continued task of introducing mobile agents to new application domains. One such new application domain is the use of a small mobile agent in a agricultural row crop field performing intra-row weeding. This paper defines requirements and scope of a process and behaviour based scripting language needed to control the weeding a...

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