نتایج جستجو برای: crop cover
تعداد نتایج: 174397 فیلتر نتایج به سال:
Increasing demand for food and bioenergy has altered the global landscape dramatically in recent years. Land use and land cover change affects the environmental system in many ways through biophysical and biogeochemical mechanisms. In this study, we evaluate the impacts of land use and land cover change driven by recent crop expansion and conversion on the water budget, carbon exchange, and car...
The work aimed at testing a methodology which can be applied to low spatial resolution satellite data to assess inter-annual crop area variations on sub-pixel to regional scales. The methodology is based on the assumption that within mixed pixels land cover variations are reflected by changes in the related hyper-temporal profiles of the Normalised Difference Vegetation Index (NDVI). We evaluat...
Physical, chemical, and biological factors of soil may reduce damage caused by plant-parasitic nematodes. Suppression of plant-parasitic nematodes is particularly challenging in soils in which there are short crop sequences, sequential susceptible host crops, or infestations of multiple nematode species. In southern Indiana, a watermelon production system involving rotations with soybean and co...
Knowledge of crop abiotic and biotic stress is important for optimal irrigation management. While spectral reflectance and infrared thermometry provide a means to quantify crop stress remotely, these measurements can be cumbersome. Computer vision offers an inexpensive way to remotely detect crop stress independent of vegetation cover. This paper presents a technique using computer vision to de...
High temporal and spatial resolution optical image time series have been proven efficient for crop type mapping at the end of the agricultural season. However, due to cloud cover and image availability, crop identification earlier in the season is difficult. The recent availability of high temporal and spatial resolution SAR image time series, opens the possibility of improving early crop type ...
The need to reduce the use of chemical inputs in agricultural ecosystems requires studying integrated ecological processes and developing new tools helping to manage them. In particular, designing landscape management strategies is a new way to improve the efficiency of services provided by biodiversity as biological control or pollination. Individual-based models are useful to better understan...
Crop coefficients are a widely used and universally accepted method for estimating the crop evapotranspiration (ETc) component in irrigation scheduling programs. However, uncertainties of generalized basal crop coefficient (Kcb) curves can contribute to ETc estimates that are substantially different from actual ETc. Limited research with corn has shown improvements to irrigation scheduling due ...
Bioenergy cropping systems have been proposed as a way to enhance United States energy security. However, research on soil physical properties, soil-surface CO2 effluxes, and soil drainage dynamics in such systems is needed to ensure environmental sustainability in the field. The objective of our research was to evaluate soil physical properties and conditions as well as soil-surface CO2 efflux...
Percent ground cover of vegetation is an important parameter for crop management. An innovational method based on features of objects was presented to automatically estimate percent ground cover of winter wheat from digital image analyses. Based on the features of wheat and its background components, an algorithm was designed to extract the percent ground cover, and the corresponding program wa...
BACKGROUND Sustainability in Agriculture In order to meet future needs of a growing human population and to achieve food security in the context of climate change, food production will likely need to increase—among other measures—while at the same time minimizing negative environmental impact (Foley et al., 2011). Sustainable intensification of agriculture (Garnett et al., 2013; Pretty and Bhar...
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