Currently, there are increased interests in growing grain and fiber hemp (Cannabis sativa L.) as well as in large-scale hemp products. Cannabis has been grown/utilized for thousands of years as a fiber, grain, and drug/medicinal plant. However, the strict control of cannabis cultivation to combat illegal use, the spread of new yarns and oilseeds, and the advent of cheap synthetic fibers caused a decreased/eliminated hemp production. Hemp has been banned in most of the world for more than seven decades; it missed out on the Green Revolution and the adoption of new technologies and varieties, creating a knowledge gap. After the 2014 and 2018 Farm Bill in the USA, hemp became legal and the land grand universities launched research programs. The ability to utilize the entire plant for multiple purposes creates opportunity for the market to value hemp products. Hemp production technology varies depending on the type of hemp cultivated (grain, fiber, or cannabinoids), soil characteristics, and environmental factors. Hemp has the potential to be a very sustainable and ecologically benign crop. Hemp roots have a significant potential for absorbing and storing heavy metals such as lead, nickel, cadmium, and other harmful substances. In addition, hemp has been proven to be an excellent carbon trap and biofuel crop. Hemp has the ability to successfully suppress weeds, and it is generally regarded a pesticide-free crop. The purpose of this paper is to examine historic and recent industrial hemp (grain and fiber) literature, with a focus on hemp agronomy and utilization.
Expert assessments for crop and range productivity of very-large arid and semiarid areas worldwide are ever more in demand and these studies require greater sensitivity in delineating the different grades or levels of soil salinity. In conjunction with field study in arid southeastern Oregon, we assess the merit of adding decision-tree analysis (DTA) to a commonly used remote-sensing method. Randomly sampled surface soil horizons were analyzed for saturation percentage, field capacity, pH and electrical conductivity (EC). IFSAR data were acquired for terrain analysis and surficial geological mapping, followed by derivation of layers for analysis. Significant correlation was found between EC values and surface elevation, bands 1, 2, 3 and 4 of the Landsat TM image, and brightness and wetness indices. Maximum-likelihood supervised classification of the Landsat images yields two salinity classes: non-saline soils (EC < 4 dSm–1), prediction accuracy of 97%, and saline soils (EC < 4 dSm–1), prediction accuracy 60%. Addition of DTA results in successful prediction of five classes of soil salinity and an overall accuracy of about 99%. Moreover, the calculated area of salt-affected soil was overestimated when mapped using remote sensing data only compared to that predicted by additionally using DTA. DTA is a promising approach for mapping soil salinity in more productive and accurate ways compared to only using remote-sensing analysis.
1 October 2006 in Hesperia: The Journal of the American School of Classical Studies at Athens
From 1997 to 2003, the Eastern Korinthia Archaeological Survey (EKAS) investigated a $350\text{-}{\rm km}^{2}$ region east of the ancient city of Corinth, focus...
Basaltic rocks of the Cima volcanic field in the southern Basin and Range province contain abundant gabbro, pyroxenite, and peridotite xenoliths. Composite xenoliths containing two or more rock types show that upper-mantle spinel peridotite was enriched by multiple dike intrusions in at least three episodes; the mantle was further enriched by intergranular and shear-zone melt infiltration in at least two episodes. The oldest dikes, now metamorphosed, are Cr-diopside websterite. Dikes of intermediate age are most abundant at Cima and consist of igneous-textured websterite and two-pyroxene gabbro and microgabbro of tholeiitic or calcalkalic parentage. The youngest dikes are igneous-textured clinopyroxenite, gabbro, and olivine microgabbro of alkalic parentage. The dikes in peridotite are interpreted as parts of a system of conduits through which tholeiitic (or calcalkalic) and alkalic magmas fed lower-crustal intrusions, which are represented by abundant xenoliths of the same igneous rock types as observed in the dikes. Mineral assemblages of dikes in peridotite indicate that an enriched uppermost mantle zone no thicker than 15 km could have been sampled. Because of their high densities, the gabbros and pyroxenites can occupy the zone immediately above the present Moho (modeled on seismic data as 10-13 km thick, with Vp 6.8 km/s) only if their seismic velocities are reduced by the joints, partial melts, and fluid inclusions that occur in them. Alternatively, these xenoliths may have been derived entirely from beneath the Moho, in which case the Moho is not the local crust-mantle boundary.