An interregional analysis of natural vegetation analogues using ERTS-1 imagery

The identification of ecological analogs of natural vegetation and food crops using ERTS-1 imagery is discussed. Signatures of four natural vegetation analogs have been determined from color photography. Color additive techniques to improve the photointerpretation are examined. Tests were conducted at test sites in Louisiana, California, and Colorado

Plan for the uniform mapping of earth resources and environmental complexes from Skylab imagery. Assessment of natural vegetation, environmental, and crop analogs

The author has identified the following significant results. For interpreting a wide range of natural vegetation analogs, S-190A color infrared and the ERTS-1 color composite were consistently more useful than were conventional color or black and white photos. Color infrared was superior for five vegetation analogs while color was superior for only three. The errors in identification appeared to associate more with black and white single band images than with multiband color. For rice crop analogs, spectral and spatial discriminations both contribute to the usefulness of images for data collection. Tests and subjective analyses conducted in this study indicated that the spectral bands exploited in color infrared film were the most useful for agricultural crop analysis. Accuracy of crop identification on any single date of Skylab images was less than that of multidate analysis due to differences in crop calendar, cultural practices used, rice variety, planting date, planting method, water use, fertilization, disease, or mechanical problems

The application of high altitude photography for vegetation resource inventories in southeastern Arizona Final report

Application of Apollo space photography and sequential high altitude NASA aircraft photography for evaluating natural and cultural resources in southeastern Arizona - ma

A scheme for the uniform mapping and monitoring of earth resources and environmental complexes: An assessment of natural vegetation, environmental, and crop analogs

The author has identified the following significant results. A study was performed to develop and test a procedure for the uniform mapping and monitoring of natural ecosystems in the semi-arid and wood regions of the Sierra-Lahontan and Colorado Plateau areas, and for the estimating of rice crop production in the Northern Great Valley (Ca.) and the Louisiana Coastal Plain. ERTS-1 and high flight and low flight aerial photos were used in a visual photointerpretation scheme to identify vegetation complexes, map acreages, and evaluate crop vigor and stress. Results indicated that the vegetation analog concept is valid; that depending on the kind of vegetation and its density, analogs are interpretable at different levels in the hierarchical classification from second to the fourth level. The second level uses physiognomic growth form-structural criteria, and the fourth level uses floristic or taxonomic criteria, usually at generic level. It is recommended that analog comparisons should be made in relatively small test areas where large homogeneous examples can be found of each analog

Response of three cereal crops in continuous arable or ley-arable rotations to fertiliser nitrogen and soil nitrogen at Rothamsted's Woburn Ley-arable experiment

The concept of improving soil fertility by ley-arable farming, developed in the 1930s in England, was practised on many “mixed” farms that had both arable crops and permanent grass. The practice declined from the 1960s as farms became predominantly arable or grassland. However, there is increasing interest in including leys in arable farming to fix carbon from carbon dioxide in the atmosphere in soil organic matter (SOM). For example, in the United Kingdom a project “Grass and herbal leys in farm network” was launched in 2018 (adas.uk, 2020) and in the European Union (EU) farmers are now required to grow a wider range of crops (ec. europa.eu, 2020. The Woburn Ley-arable experiment started in 1938 has compared six rotations, two with 3-yr leys, two with 8-yr leys and two with continuous arable crops on the yields of two cereal test crops. The effect of these rotations on SOM is given elsewhere (Johnston et al., 2017). Here we give the yields of both test crops in each of the six rotations for 21 years starting in 1981. We discuss the response to four levels of applied fertiliser nitrogen (N), the effect of rotation, the level of SOM and the availability of soil N. Where no fertiliser N was added, crop yields increased as % N in soil increased, but, with sufficient fertiliser N there was little benefit from the extra N in the soil. Yields of winter wheat were larger after the 3-year grass ley than in the all-arable rotations and larger again following the grass/clover ley. Less fertiliser N was needed to achieve the yields after the leys than in the all-arable rotations. Yields of the second cereal crop following 3- or 8-yr leys were also larger than those in all-arable rotations but there was no difference between the leys. However, the extra N available from the leys and the increases in yield were modest. If leys are to be introduced into mainly arable farming systems, they may need to be subsidised to make them financially viable

Natural resources inventory and monitoring in Oregon with ERTS imagery

Multidiscipline team interpretation of ERTS satellite and highflight imagery is providing resource and land use information needed for land use planning in Oregon. A coordinated inventory of geology, soil-landscapes, forest and range vegetation, and land use for Crook County, illustrates the value of this approach for broad area and state planning. Other applications include mapping fault zones, inventory of forest clearcut areas, location of forest insect damage, and monitoring irrigation development. Computer classification is being developed for use in conjunction with visual interpretation

High-frequency homogenization for periodic media

This article is available open access through the publisher’s website at the link below. Copyright @ 2010 The Royal Society.An asymptotic procedure based upon a two-scale approach is developed for wave propagation in a doubly periodic inhomogeneous medium with a characteristic length scale of microstructure far less than that of the macrostructure. In periodic media, there are frequencies for which standing waves, periodic with the period or double period of the cell, on the microscale emerge. These frequencies do not belong to the low-frequency range of validity covered by the classical homogenization theory, which motivates our use of the term ‘high-frequency homogenization’ when perturbing about these standing waves. The resulting long-wave equations are deduced only explicitly dependent upon the macroscale, with the microscale represented by integral quantities. These equations accurately reproduce the behaviour of the Bloch mode spectrum near the edges of the Brillouin zone, hence yielding an explicit way for homogenizing periodic media in the vicinity of ‘cell resonances’. The similarity of such model equations to high-frequency long wavelength asymptotics, for homogeneous acoustic and elastic waveguides, valid in the vicinities of thickness resonances is emphasized. Several illustrative examples are considered and show the efficacy of the developed techniques.NSERC (Canada) and the EPSRC