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1.
Silicified anthoecia (fertile le'mmas and paleas) of grasses (Berriochloa communis, Berriochloa primaeva, and Berriohldoa cf. nova) were found in, the oral cavity and rib cage articulated skeletons of Teleoceras major buried in late Clarendonian volcanic ash in. Nebraska The plant fossils, thought to be food residues, help clarify, the enigmatic paleobiological role, of Teleocears, which had hippotamus-like porportions but very high-crowned teeth. Telecoceras was probably amphbious, but siliceous grasses formed a significant portion of its diet. 相似文献
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Thomasson JR 《Science (New York, N.Y.)》1978,199(4332):975-977
Morphological study of fossil grass anthoecia of Berriochloa and Nassella collected from Miocene-Pliocene strata in Kansas has revealed well-preserved epidermal structure. This seems to be the first micromorphological information known from fossil grass floral bracts. The epidermal pattern on the lemma in the fossils and their living counterparts are evidence in support of the view that the North American species of Stipa of the section Hesperostipa Elias and species of Piptochaetium have a common ancestry in Berriochloa, and that species of both taxa have been distinct from species of the Nassella, Oryzopsis, and other Stipa since at least the Miocene or Pliocene. 相似文献
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A fossil leaf fragment collected from the Ogallala Formation of northwestern Kansas exhibits features found in taxa of the modern grass subfamily Chloridoideae. These include bullet-shaped, bicellular microhairs, dumbbell-shaped silica bodies, cross-shaped suberin cells, papillae, stomata with low dome- to triangular-shaped subsidiary cells, and Kranz leaf anatomy. The leaf fragment extends the fossil record of plants that show both anatomical and external micromorphological features indicating C(4) photo-synthesis back to the Miocene. On the basis of associated mammals, the leaf fragment is assigned a Hemphillian age (7 to 5 million years ago). 相似文献
4.
The ability to map profit across a cotton field would enable producers to determine where money is being made or lost on their farms and to implement precise field management practices to facilitate the highest return possible on each portion of a field. Mapping profit requires knowledge of site-specific costs and revenues, including yield and price. Price varies site-specifically because fiber quality varies, so mapping fiber quality is an important component of profit mapping. To map fiber quality, the harvest location of individual cotton bales must be known, and thus a system to track the harvest location of cotton modules must be available. To this end, a wireless module-tracking system was recently developed, but automation of the system is required before it will find practical use on the farm. In Part 1 of this report, research to develop automatic triggering of wireless messages is described. In Part 2, research to enable the system to function with multiple harvesting machines of the same type in the same field - a common situation in commercial cotton farming - is described along with testing of the entire automated wireless module-tracking system (WMTS). An RFID system was incorporated, and it enabled the WMTS to correctly and consistently differentiate among various harvesting vehicles. The improved WMTS subsequently sent wireless messages to the correct machines when cotton transfers were made in the presence of multiple harvest machines. Overall testing proved that the automated WMTS worked largely as designed. When both complete and partial cotton basket dumps were simulated, the correct wireless-messaging decision was made 100% of the time. 相似文献
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The ability to map profit across a cotton field would enable producers to determine where money is being made or lost on their farms and to implement precise field management practices to facilitate the highest return possible on each portion of a field. Mapping profit requires knowledge of site-specific costs and revenues, including yield and price. Price varies site-specifically because fiber quality varies, so mapping fiber quality is an important component of profit mapping. To map fiber quality, the harvest location of individual cotton bales must be known, and thus a system to track the harvest location of cotton modules must be available. To this end, a wireless module-tracking system was recently developed, but automation of the system is required before it will find practical use on the farm. In Part 1 of this report, research to develop automatic triggering of wireless messages is described. In Part 2, research to enable the system to function with multiple harvesting machines of the same type in the same field - a common situation in commercial cotton farming - is described along with testing of the entire automated wireless module-tracking system. To automate wireless-message triggering, a sensing and control system was added to a harvester to indicate when the machine is dumping a basket load of cotton so that wireless messages can be automatically sent from the harvester to subsequent field machines. This automated system was incorporated into the existing wireless module-tracking system, field tested, and it ultimately operated as designed, without human intervention. Linking data collected with this system together with cotton classing data enabled the creation of fiber-quality maps. 相似文献
7.
White Emma L. Thomasson J. Alex Auvermann Brent Kitchen Newell R. Pierson Leland Sandy Porter Dana Baillie Craig Hamann Hendrik Hoogenboom Gerrit Janzen Todd Khosla Rajiv Lowenberg-DeBoer James McIntosh Matt Murray Seth Osborn Dave Shetty Ashoo Stevenson Craig Tevis Joe Werner Fletcher 《Precision Agriculture》2021,22(1):306-315
Precision Agriculture - Data-centric technology has not undergone widespread adoption in production agriculture but could address global needs for food security and farm profitability. Participants... 相似文献
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The natural regeneration of soil structure following compaction was studied on a stagnogleyic paleoargillic brown earth (Albaquic Paleudalf) at Rothamsted Experimental Station. The compaction treatment was produced by wheelings, and the area between the wheelings was used as the control.The wheeled and unwheeled areas were sampled 4 times, in spring and after harvest in 1979 and 1980 The following techniques were used to monitor regeneration: measuring the profile of the soil surface in the field and laboratory measurements of air-filled pore space, water retention, shrinkage and clod density, micromorphometry and mercury intrusion.Compaction decreased the macroporosity (pores >60 μm diameter) by over a half. Pores <6 μm diameter were unaffected by compaction. Natural regeneration of porosity in the top 5 cm was achieved within 18 months, but the soil below remained compacted for longer. The regenerated structure consisted mainly of planar voids induced by physical processes unlike the unwheeled soil which was characterised by packing voids and biopores. 相似文献
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Identifying the vulnerability of subsoils to compaction damage is an increasingly important issue both in the planning and execution of farming operations and in planning environmental protection measures. Ideally, subsoil vulnerability to compaction should be assessed by direct measurement of soil bearing capacity but currently no direct practical tests are available. Similarly, soil mechanics principles are not suitably far enough advanced to allow extrapolation of likely compaction damage from experimental sites to situations in general. This paper, therefore, proposes a simple classification system for subsoil vulnerability to compaction based for field use on local soil and wetness data at the time of critical trafficking, and, at European level, on related soil and climatic information. Soil data are readily available ‘in Country’ or from the European Soil Database and climatic data are stored in the agrometeorological database of the MARS Project. The vulnerability to compaction is assessed using a two-stage process. First, the inherent susceptibility of the soil to compaction is estimated on the basis of the relatively stable soil properties of texture and packing density. Second, the susceptibility class is then converted into a vulnerability class through consideration of the likely soil moisture status at the time of critical loadings. For use at local level, adjustments are suggested to take account of possible differences in the support strength of the topsoil and specific subsoil structural conditions. The vulnerability classes proposed are based on profile pit observations, on a wide range of soils examined mainly in intensively farmed areas where large-scale field equipment is employed. A map of soil susceptibility to compaction in Europe has been produced, as the first stage in developing a more rigorous quantitative approach to assessing overall vulnerability than has been possible hitherto. 相似文献
10.
A system including wireless-communication and GPS technologies was designed, constructed and field tested to enable site-specific
crop management in cotton production in the form of fiber-quality mapping. The system is comprised of three functional sub-systems
associated with the three machines typically used in cotton harvesting: harvester, boll buggy and module builder. Harvest
area for a basket load of cotton is recorded with GPS, and the module into which a basket is dumped is tracked through wireless
communication among the sub-systems. In three field tests, the system was easily installed on equipment and performed as designed.
Fiber-quality maps were produced by combining the GPS-based module area data collected during harvest with bale-level fiber-quality
data measured at a cotton classing office after ginning. Statistical analysis showed significant differences in most cotton
fiber properties among mapped modules, and spatial trends were identified. The system provides a useful tool for studying
spatial variability in cotton fiber quality. 相似文献