Articles de revues sur le sujet « Early watergra »

Molecular techniques are useful tools for solving taxonomic confusion among species. Polymerase chain reaction (PCR) and polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) methods were applied for the identification of barnyardgrass, early watergrass, and late watergrass. Total DNA was extracted from 266 accessions, which were collected from different rice growing areas of Turkey. The two primer sets (trn-a and trn-b1, and trn-c and trn-d) specific to a target region of the intergenic spacer between trnT (UGU) and trnL (UAA) and the entire intron region of trnL (UAA), respectively, were used in PCR amplifications. Of the 266 accessions of Echinochloa spp., only eight accessions gave a similar fragment size, which was slightly shorter than 495 bp. The PCR product obtained with the primers trn-a and trn-b1 gave two fragments when EcoRI restriction enzyme was used in barnyardgrass and early watergrass. However, not all accessions of late watergrass were digested with this enzyme. In contrast to EcoRI, the PCR product obtained using the trn-c and trn-d primer set was digested into two fragments by using AluI restriction enzyme in all accessions of late watergrass; whereas, it was not digested in barnyardgrass and early watergrass. This molecular differentiation among barnyardgrass, early watergrass, and late watergrass supports the hypothesis that late watergrass is not a synonym of early watergrass in Turkish accessions.

Experiments were conducted to study the effect of application rate, growth stage, and tank-mixing azimsulfuron or bentazon on the activity of cyhalofop, clefoxydim, and penoxsulam against two morphologically distinctEchinochloaspecies from rice fields in Greece. Mixtures of penoxsulam with MCPA were also evaluated. Cyhalofop (300 to 600 g ai/ha) applied at the three- to four-leaf growth stage provided 62 to 85% control of early watergrass but 41 to 83% control of late watergrass averaged over mixture treatments. Control ranged from 37 to 80% for early watergrass and from 35 to 78% for late watergrass when cyhalofop was applied at the five- to six-leaf growth stage averaged over mixture treatments. Mixtures of cyhalofop with azimsulfuron or bentazon reduced efficacy on both species irrespective of growth stage or cyhalofop application rate compared with cyhalofop alone. Clefoxydim (100 to 250 g ai/ha) applied alone at the three- to four-leaf growth stage provided 98 to 100% control of early watergrass and 91 to 100% control of late watergrass; when clefoxydim was applied alone at the five- to six-leaf growth stage the control obtained was 91 to 100% for early watergrass and 79 to 100% for late watergrass. Mixtures of clefoxydim with azimsulfuron or bentazon reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Penoxsulam (20 to 40 g ai/ha) applied alone provided 94 to 100% control of both species at both growth stages. Mixtures of MCPA with penoxsulam reduced efficacy on late watergrass at the early growth stage and on both species at the late growth stage. Mixtures of penoxsulam with azimsulfuron or bentazon reduced efficacy only on late watergrass at the late growth stage.

The photosynthetic responses of rice (C3) and threeEchinochloaspecies (C4), barnyardgrass, early watergrass, and late watergrass, to changes in CO2intercellular partial pressure, light intensity, and leaf temperature were investigated under laboratory conditions. The threeEchinochloaspecies exhibited photosynthetic responses characteristic of C4plants. The three weedy species showed higher efficiency for CO2utilization at low CO2intercellular partial pressure (CO2i) than rice. Compensation and saturation of CO2i for photosynthesis were lower in the weedy species than in rice. The maximum photosynthetic rates at high light intensity were 33.5, 32.7, 30.5, and 21.5 μmol CO2m-2s-1for barnyardgrass, early watergrass, late watergrass, and rice, respectively. Photosynthesis temperature optimum was 35 to 37 C for the threeEchinochloaspecies and 33 C for rice. Overall, under simulated summer conditions, the four taxa showed a photosynthetic ability hierarchy with regard to gas exchange performance as follows: barnyardgrass ≥ early watergrass > late watergrass > rice.

Experiments were conducted to evaluate the effect of application rate, growth stage, and tank mixing azimsulfuron, bentazon, MCPA, propanil, or cyhalofop on the efficacy of bispyribac–sodium against early watergrass and late watergrass from rice fields in northern Greece. Mixtures of bispyribac–sodium with the insecticides carbaryl, diazinon, and dichlorvos were also evaluated. Bispyribac–sodium (24 to 36 g ai/ha) applied alone at the three- to four-leaf growth stage provided 89 to 100% control of early watergrass and 84 to 100% control of late watergrass. When bispyribac–sodium was applied alone at the five- to six-leaf growth stage of early watergrass and late watergrass, control ranged from 78 to 100% and 71 to 100%, respectively. Mixtures of bispyribac–sodium with azimsulfuron provided better control of both species at any growth stage than bispyribac–sodium applied alone. On the contrary, mixtures of bispyribac–sodium with bentazon, MCPA, or propanil were less effective on both species at any growth stage than bispyribac–sodium applied alone. A slight efficacy reduction occurred on both species for the mixture of bispyribac–sodium with cyhalofop. Mixtures of bispyribac–sodium with the insecticides carbaryl or dichlorvos showed reduced efficacy on both species, whereas increased efficacy on both species was observed for mixtures of bispyribac–sodium with diazinon as compared with the single application of bispyribac–sodium.

Resistance to the thiocarbamates has been selected in early watergrass populations within the rice-growing region of California. To elucidate the processes contributing to the spread of resistance among rice fields, we characterized the genetic diversity and differentiation of thiobencarb-resistant (R) and thiobencarb-susceptible (S) populations across the Central Valley using microsatellite markers. A total of 406 individuals from 22 populations were genotyped using seven nuclear microsatellite primer pairs. Three analytical approaches (unshared allele, Shannon–Weaver, and allelic-phenotype statistics) were used to assess genetic diversity and differentiation in the allohexaploid species. Low levels of genetic variation were detected within populations, consistent with other highly selfing species, with S populations tending to be more diverse than R populations.FSTvalues indicated that populations were genetically differentiated and that genetic differentiation was greater among S populations than R populations. Principal coordinate analysis generated two orthogonal axes that explained 88% of the genetic variance among early watergrass populations and differentiated populations by geographical region, which was associated with resistance phenotype. A Mantel test revealed that genetic distances between R populations were positively correlated with the geographical distances separating populations. Taken together, our results suggest that both short- and long-distance seed dispersal, and multiple local and independent evolutionary events, are involved in the spread of thiobencarb-resistant early watergrass across rice fields in the Sacramento Valley. In contrast, resistance was not detected in early watergrass populations in the San Joaquin Valley.

In five field experiments from 1986 to 1988, herbicides were evaluated alone and in combinations for weed control in water-seeded rice. Combinations of bensulfuron with either molinate or thiobencarb applied into the paddy water at the 2-leaf stage of rice, controlled all broadleaf and sedge weeds, and 92% or more early watergrass. These combinations were equivalent to a commercial standard of molinate at the 2-leaf stage followed by a separate application of bentazon to the drained paddy at midtillering.

Data from a comprehensive literature survey for the first time provide stage-level resolution of Early Cretaceous through Pleistocene species diversity for nongeniculate coralline algae. Distributions of a total of 655 species in 23 genera were compiled from 222 publications. These represent three family-subfamily groupings each with distinctive present-day distributions: (1) Sporolithaceae, low latitude, mainly deep water; (2) Melobesioid corallinaceans, high latitude, shallow water, to low latitude, deep water; (3) Lithophylloid/mastophoroid corallinaceans, mid- to low latitude, shallow water.Raw data show overall Early Cretaceous-early Miocene increase to 245 species in the Aquitanian, followed by collapse to only 43 species in the late Pliocene. Rarefaction analysis confirms the pattern of increase but suggests that scarcity of publications exaggerates Neogene decline, which was actually relatively slight.Throughout the history of coralline species, species richness broadly correlates with published global paleotemperatures based on benthic foraminifer δ18O values. The warm-water Sporolithaceae were most species-abundant during the Cretaceous, but they declined and were rapidly overtaken by the Corallinaceae as Cenozoic temperatures declined.Trends within the Corallinaceae during the Cenozoic appear to reflect environmental change and disturbance. Cool- and deep-water melobesioids rapidly expanded during the latest Cretaceous and Paleocene. Warmer-water lithophylloid/mastophoroid species increased slowly during the same period but more quickly in the early Oligocene, possibly reflecting habitat partitioning as climatic belts differentiated and scleractinian reef development expanded near the Eocene/Oligocene boundary. Melobesioids abruptly declined in the late Pliocene-Pleistocene, while lithophylloid/mastophoroids increased again. Possibly, onset of glaciation in the Northern Hemisphere (~2.4 Ma) sustained or accentuated latitudinal differentiation and global climatic deterioration, disrupting high-latitude melobesioid habitats. Simultaneously, this could have caused moderate environmental disturbance in mid- to low-latitude ecosystems, promoting diversification of lithophylloids/mastophoroids through the “fission effect.”Extinction events that eliminated >20% of coralline species were most severe (58–67% of species) during the Late Cretaceous and late Miocene-Pliocene. Each extinction was followed by substantial episodes of origination, particularly in the Danian and Pleistocene.

Introduction: Birds are an integral part of ecosystem, they are commonly found all over the world. They can be parasitized by a wide variety of endo-parasites. Objectives/Aim: The current study conducted to identify and investigate the prevalence of endo-parasites from various captive bird species at main campus of PMAS-Arid Agriculture University, Rawalpindi. Methodology: Different standardized methods were used to collect fecal pellets from each bird species in early morning in a plastic bag and transferred to the National Veterinary laboratory (NVL), Islamabad for parasitological examination, eggs, oocytes, cysts and larva of pathogens. Prevalence of endo-parasites was estimated through geometric mean at confidence interval of 95%. Results: Total 403 fecal samples were collected from 13 bird species, 10 out of 13 avian species were found infected with endoparasites. The data on percentage occurrence of infection in avian species viz; pigeons (41.9%) were the most infected with endo-parasites as compared to golden pheasant (19.3%), pea cock (16.1%), cochin hen (12.9%), ring neck pheasant (9.6%), aseel hen (6.45%), polish hen (6.4%), brown hen (3.2%), red jungle fowl (3.2%) and bentum hen (3.2%). However, all of Budgerigar parrots, ducks and guinea fowl were not infected. It was found that Eimeriasp was more prevalent and isolated from Aseel hen (38.7%) and Golden pheasant (29.03%). Trichuris spp. was also more prevalent and isolated from golden pheasant (38.7 %). and other pathogens Ascaris spp. isolated from golden pheasant (16.1%) and peafowl (6.4 %), followed by Ascaridia spp. isolated from polish hen (16.1 %). It is concluded that Pigeons were most infected bird species and Eimeria spp, (38.7 %) and Trichuris spp. (38.7 %) were the most prevalent pathogens. Conclusion: Parasitic load can be managed by providing better healthcare facilities to birds, proper cleaning of waterers, vaccination of birds, proper nutrition and management of environmental conditions.

Cooking pits – in clusters or in rowsCooking pits can occur either arranged in one or more rows, following a roughly parallel course, or in clusters of up to several hundred closely-spaced examples with no apparent pattern in their location. This type of structure is known from Southern Scandinavia, Germany and Poland. Most cooking-pit systems belong to the Bronze Age, but occasional examples date from the Early Iron Age.The cooking-pit complexes are described according to the following characteristics: 1) location in the landscape, 2) proximity to water, 3) distance to contemporary settlements, hoards and graves, 4) uniformity of form and content and 5) paucity of finds (Heidelk-Schacht 1989).In recent years in Denmark, attention has become focussed on cooking-pit systems and many new examples have been investigated (fig. 1). There are at least 42 known sites (fig. 2) comprising a total of at least 4300 cooking pits. However, as most rows or clusters of cooking pits have not been fully excavated, the real number is much greater. There are virtually no da­table finds from the pits, as a consequence of which there is a tendency to date these features alone on the basis of their form and structure. Radiocarbon dates are the most important source when dating and many new sites, especially with uni-seriate arrangements of cooking pits, have been scientifically dated.In this article, the cooking-pit question is examined with a point of departure in a uni-seriate system at Frammerslev in Salling and a complex system at Brok­bakken, Bjerringbro.FrammerslevDuring Skive Museum’s investigations in 2002 and 2006, discoveries included a uni-seriate cooking-pit system and a 31 m-long row of postholes 200 m further to the east, parallel to the row of cooking pits. The row of cooking pits (fig. 3) lies on a plateau located on a large promontory. The promontory hosts several concentrations and a row of burial mounds, constituting a marked feature in the landscape, also in the Late Bronze Age. The row of cooking pits runs directly towards a burial mound in both directions. Six cremation graves were found in the burial mounds, indicating that they were also used for burial purposes in the Late Bronze Age. There is no settlement in the vicinity.The row of cooking pits comprises 33 pits located in extension of one another, forming a 67 m-long northeast-southwest oriented row (fig. 4). Towards the northeast, the row continues in a more scattered fashion with a further seven cooking pits. In the middle of the series there is a complex of at least four cooking pits ( fig. 4, no. 1), of which two are included in the row. Repeated re-cutting can be seen in the complex and this is the only site so far where repeated use can be documented. At Frammerslev, there are subsidiary cooking pits associated with the row – a feature also seen at Roerstensgård and Bækmarksgård.The other cooking pits in the Frammerslev row are circular or elongate-oval. On the basis of the deposits in the pits, a typology has been constructed (fig. 5).When the cooking pits are classified according to the presence or absence of a compact charcoal-rich layer at their base, as well as one or two overlying layers, two main types can be identified, one with three, and one with two sub-types:Type 1 includes cooking pits with a black, compact charcoal-rich basal layer. Type 1a has a basal layer of charcoal and over this a yellow to brownish-yellow layer with red-burnt areas and, uppermost, brown topsoil material with scattered fire-shattered stones and charcoal. There may be red-burnt soil at the edge of the pit. There are, accordingly, three layers within the cooking pit and the red-burnt layer over the charcoal is unbroken and follows the course of any subsidence in the pit. Type 1b has brown topsoil-like fill directly over the basal charcoal layer. There are, accordingly, only two layers in the cooking pit. Type 1c comprises a black charcoal-rich basal layer with a substantial content of fire-shattered stones in the same layer as the charcoal, by which it distinguishes itself from types 1a and 1b. Type 2 covers cooking pits lacking black charcoal layers and possibly also without fire-shattered stones. In the case of type 2a, the whole pit is filled with brown clay, possibly lacking, or with only occasional scattered, fire-shattered stones and with very little charcoal. There is no red-burnt subsoil associated with these pits. With type 2b, the basal layer comprises clay with a very low content of charcoal and occasional fire-shattered stones or yellow to brownish-yellow clay with many small pieces of fire-shattered stone but no charcoal and no red-burnt clay.As can be seen from the overview (fig. 6) of the cross-sections of the cooking pits, there is great uniformity within, respectively, types 1a and 2a.Cooking pits of type 1 were primarily hearths where the cooking stones were heated in situ and the subsoil has become coloured by the effect of the intense heat. Subsequently, the pit served its purpose as, presumably, a cooking place for the roasting of meat. While the stones were still hot the fire was extinguished by being covered by thin layers of soil being thrown in; in several cases these can be seen to have acquired a reddish colour due to the effect of the heat. In several of the cooking pits there are very small fire-shattered stones, presumably the result of repeated use. Finally, the pit was either intentionally covered after its last usage or stood open and, with time, became filled with soil-rich culture layers. Accordingly, the cooking pit represents a complete series of events.The cooking pits of main type 2, with no or few fire-shattered stones, no or only a little charcoal and lacking red-coloured subsoil, must be explained in a different way. Either fire was never lit in the cooking pit – in which case it is difficult to maintain the term cooking pit and the pit could perhaps represent a kind of preliminary phase to its actual use, or the pit has been completely cleaned out after use, resulting in only the overlying layers being present. This type represents perhaps the pre- and post-phases of the actual cooking-pit activity.By examining the distribution of types 1 and 2, a pattern emerges which can provide the basis for an interpretation of the uni-seriate structure at Frammerslev (see fig. 4). Cooking pits of type 1 are the deepest and lie on both sides of the large central pit. Cooking pits of type 2 lie further away at both the northeastern and southwestern ends. This distribution of types suggest that the most commonly-used features are the central ones and that the row grew successively out from this core. Two shallow pits of type 2 furthest to the north could perhaps be the beginning of the next stage.The cooking pits at Frammerslev have not been archaeologically dated on the basis of artefacts. Two cooking pits of type 1 have been radiocarbon dated (fig. 7). If account is taken of the greatest uncertainty, the calibrated dates are, respectively, 860-790 BC and 1070-830 BC, i.e. Late Bronze Age, periods IV-V.Uni-seriate structures are found on Funen and Zealand and in Central and Northwestern Jutland and have many common features. They have often a marked location in the landscape, several occur on or near the highest point, for example on larger or smaller promontories extending out into a wetland area. Virtually all the uni-seriate cooking-pit rows lie in the vicinity of a wetland. Five out of 11 uni-seriate cooking-pit rows point in the direction of a burial mound. It is difficult to judge whether the cooking-pit rows lie remotely relative to settlements and burial grounds; investigation of even greater areas would be required in order to establish with certainty the absence of contemporary sites in the vicinity. This situation is further complicated by the fact that the houses from this period appear to be located quite a distance apart.The uni-seriate cooking-pit structures are, as a rule, lacking in finds. Nine uni-seriate cooking-pit rows have been radiocarbon dated (fig. 9). The radiocarbon dates reveal that the cooking-pit systems were used in the Late Bronze Age, periods IV-V, especially in the years between 950 and 800 BC.Brokbakken I-IIIIn the period between 1990 and 2008, Viborg Stiftsmuseum carried out several arch­aeological investigations on a 20 hectare site at Bjerringbro. These excavations have been named Brokbakken I-III. By way of the excavations at Brokbakken it has proved possible to demonstrate that large and small concentrations of cooking pits can be found in the vicinity of a multi-seriate system of cooking pits.Brokbakken comprises a delimited promontory (fig. 10), bordered on three sides by 8-10 m high steep slopes and gullies running out towards the flat Gudenå river valley. To the southeast, the promontory slopes gently without any natural boundary. The concentration of cooking pits at Brokbakken II lies a little withdrawn from the edge of the promontory, facing out towards a small gulley. The multi-seriate system of cooking pits, Brokbakken III, lies along the edge of an extensive valley which, 1.5 km distant, runs into the Gudenå.Brokbakken I yielded a concentration of 30 cooking pits, especially of type 1b, together with refuse pits from the Late Bronze Age, periods IV-V.At Brokbakken II, there is a concentration of 85 densely-placed cooking pits, primarily of type 1c (basal layer comprising a mixture of charcoal and fire-shattered stones), as well as several smaller clusters (fig. 11). There are a few finds, including a collection of sherds (fig. 12) from a c. 23 cm high vessel. Radiocarbon dating of a cooking pit shows that, when the greatest uncertainty is taken into account, it was in use between 1130 and 840 BC (see fig. 7), i.e. in Late Bronze Age, periods IV-V.At Brokbakken III, a multi-seriate system of cooking pits was investigated in 1997. This comprised 110 examples arranged in three to four rows (termed rows F, G, I and J), forming a fan shape (fig. 13), as well as 42 cooking pits lying individually or in smaller or larger concentrations. The majority of the cooking pits are circular or oval and they vary in size.The cooking pits at Brokbakken III are built up according to the same basic principles as those at Frammerslev, and cooking pits of types 1b, 2a and 2b are present. Cooking pits with a compact layer of charcoal at the base are, conversely, absent, but these are presumably replaced by cooking pits of type 1c. Overall, it can be seen that the majority of the cooking pits, in all 55% of all those which were sectioned, belong to type 1b.When account is taken of the greatest uncertainty in the radiocarbon dates, the cooking pit alignments can be seen to have been in use in the period 1020-800 BC, i.e. Late Bronze Age, periods IV-V.Multi-seriate cooking-pit systems are known from 10 localities on Zealand, Funen and Bornholm, and in Jutland. They are located on hillsides or level ground with small elevations or on flat promontories extending out into wetland areas. The cooking-pit rows are found by bogs, lakes and watercourses. The multi-seriate cooking-pit systems have no fixed orientation and several structures follow a meandering or curved course. At the known localities, there are between two and 15-16 rows of cooking pits, and it seems that systems comprising three to four rows are commonest. Five structures have been dated to the Late Bronze Age, periods IV, V and VI.Concentrations of cooking pits with more than 25 cooking pits are known from 20 localities on Zealand, Møn and Funen and in Jutland (see fig. 2). The concentrations have very diverse locations – some are on or by marked hill tops or on an even plateau, while others occur on sloping terrain as well as on the floor of a valley. The cooking-pit concentrations lie in the vicinity of lakes, watercourses or bogs or close to open water.A cooking-pit concentration at Fårdalgård (fig. 19) lies in undulating terrain, virtually a promontory. On the plateau behind the cooking pits, settlement traces from the Late Bronze Age have been found. Further away, there are burial mounds and only 100 m away lies the find site for the famous Fårdal hoard. The latter is dated to the Late Bronze Age, period V, and the system of cooking pits can, as a whole, be dated on the basis of pottery to the Late Bronze Age; this also applies to other concentrations of cooking pits.ConclusionSystems of cooking pits must be seen in a wider context, where their topographic location and information on the area’s settlements, burial grounds and hoards are included in the evaluation. On the basis of topographic location, it is reasonable to suggest that uni-seriate structures could have had a different function from multi-seriate examples, and that the complexity is further increased if there are both rows and concentrations of cooking pits at the same site.Uni-seriate structures are often located high up in the vicinity of, or pointing towards, burial mounds containing finds from both the Early and Late Bronze Age. These structures should probably be interpreted in conjunction with the burial mounds, and be seen as cultic features employed in connection with burials or other ceremonies associated with the cult. Their physical form, a long row of cooking pits at Frammerslev, constitutes a clear eastern demarcation and the associated row of postholes is a clear western demarcation of the row of burial mounds. The group of burial mounds towards the north could be a form of transverse demarcation of the area. In this way, areas are created within the landscape, each of different significance – outside and inside – a totally ritual landscape.The multi-seriate systems and large concentrations of cooking pits are often conspicuously located in areas with watercourses, lakes or bogs or facing out towards open water. Several sites, such as Brokbakken I-III and Fårdalgård, are located on marked promontories extending out into large river valleys where offerings have been found in the vicinity. It seems obvious to imagine these large concentrations and numerous rows of cooking pits as the result of many people’s activities in connection with great gatherings and cultic ceremonies. The argument can be made for an supra-regional presence of people, and the site can, therefore, be interpreted as a gathering place for a larger area.Figure 20 shows the location of the cooking-pit concentrations relative to the main watercourses in Central Jutland: Gudenå, Skals Å and Nørre Å. There is about 30 km in a straight line from the concentrations of cooking pits in Lynderup to the cooking pits of both Brokbakken I-III and Munkebo. Within this area, with its meandering river systems, and the areas of land they delimit, there are several systems of cooking pits. Their location in the landscape suggests some form of territorial division. We can almost predict the location of the next structure in the landscape!Brokbakken I-III also demonstrates, at a superior level, a form of division of the landscape. High up on the promontory there are cooking pits and traces of metalworking delimited by the slightly lower-lying multi-seriate system of cooking pits. Below the promontory by the Gudenå there is an offering area. On the plateau nearest the promontory there are scattered traces of settlement and in the burial mounds further away the rich graves of important people. If this interpretation of the landscape is correct, the systems of cooking pits can have had a function as markers in the ritual landscape.The investigations of rows of cooking pits show that there are differences in the physical composition of the individual structures, but it is the fill layers which form the basis for a more subtle interpretation of their function. These layers could represent various stages of use and cleaning out. The investigation at Frammerslev shows that the rows of cooking pits were used several times, and it is possible to argue for successive expansion. A form of division into separate sections is also seen at several sites.On the basis of many ethnographic parallels and practical experiments, it has been suggested that the cooking pits were used to cook meat. If we accept that the cooking pits of type 1 were used for cooking, and that food for 10 people can be prepared in a single pit, the systems of cooking pits at Frammerslev could have been used to prepare food for 60-100 people, while those at Brokbakken III could perhaps provide for 800-1000 individuals.Inge Kjær KristensenMuseum SallingSkive Museum

Abstract Late watergrass is a competitive weed of rice that is well adapted to both aerobic and anaerobic environments. Cultural controls such as a stale-seedbed and alternating from wet- to dry-seeding have been proposed as management options. However, the effects of these systems on its emergence and early growth are unknown. The objective of this study was to modify a previously developed population-based threshold model (PBTM) to predict emergence and early growth under field conditions. In 2013, a series of experiments were conducted at the California Rice Experiment Station (CRES) in Biggs, CA, to evaluate emergence and early growth of multiple herbicide–resistant and -susceptible late watergrass at four burial depths (0.5, 2, 4, and 6 cm) under three irrigation regimes: continuously flooded (CF), daily flush (DF), and intermittent flush (IF). Resistant plants emerged at a significantly higher rate under the IF treatment (P < 0.05). Both biotypes showed decreasing emergence with increasing depth, and no plants emerged from the 4- or 6-cm depths in the CF treatment. Using the Gompertz growth curve, resistant plants had greater predicted growth rates (k), lower predicted maximum heights (h max ), and a shorter time to predicted maximum growth rate (t m ) than susceptible plants under the CF and DF treatments. Under the IF treatment, the susceptible plants had greater k, lower h max , and shorter time to predicted t m . Information about burial depth and irrigation was incorporated into a previously developed PBTM for late watergrass, and validated at the CRES in a field with a susceptible late watergrass population in 2013 and 2014, under two irrigation systems, CF and IF. Model fit was best in the CF treatments (average Akaike information criteria [AIC] = 199.05) compared to the IF treatments (average AIC = 208.6).

A 3-year phytotron study was conducted in Suwon (37.27°N, 126.99°E), Korea, to evaluate and model the effects of elevated temperature on rice-weed competition. The dry weight and the number of panicles in rice were the most susceptible components to weed interference during the early growth of rice, regardless of weed species, while other yield components, including the number of grains, % ripened grain, and 1000-grain weight, were more susceptible to elevated temperature. A rectangular hyperbolic model well demonstrated that rice grain yield was affected by weed interference under elevated temperature, showing that the competitiveness of late watergrass (Echinochloa oryzicola) and water chestnut (Eleocharis kuroguwai) increased under elevated temperature conditions. Quadratic and linear models well described the effects of elevated temperature on the weed-free rice grain yield and weed competitiveness values of the rectangular hyperbolic model for the two weed species, respectively. Thus, a combined rectangular hyperbolic model incorporated with the quadratic and linear models well demonstrated the effects of elevated temperature and weed interference on rice grain yield across years. Using the combined model and estimated parameters, the rice grain yields were estimated to be 58.9, 48.5, 41.3, and 35.9% of the yields under weed-free conditions for 80 plants m−2 of late watergrass and 86.8, 64.3, 51.1, and 42.3% of the yields under weed-free conditions for 80 plants m−2 of water chestnut at 1,300, 1,500, 1,700, and 1,900°C·days of accumulated growing degree days (GDD; from transplanting to flowering, 89 days), respectively. The combined model developed in this study can provide an empirical description of both the elevated temperature and weed interference effects on rice yield and can be used for predicting rice grain yields due to weed interference under future elevated temperature conditions.

Abstract Mass medication to manage population health can be achieved by providing therapeutics in the drinking water. Young nursery pigs are highly sensitive to the flavor and smell of water. Medications that reduce water palatability often lead to an interruption in water and feed intake. With the availability of several generic water-soluble antimicrobials for pigs, questions have arisen about their palatability compared with the original product. In this study, we compared the intake of water containing tiamulin hydrogen fumarate from two different manufacturers with the intake of unmedicated water. The hypothesis was that the intake of tiamulin-containing water would be similar to unmedicated water. Water intake was monitored upon entry into the nursery and just prior to leaving the nursery. Also, average daily gain (ADG) and feed efficiency (FE) were determined. A total of 300 pigs were individually weighed (4.2–10.9 kg; avg = 6.8 kg) for randomization to pen (n = 30 pens). The experiment had two time points: 1) early nursery (periods 1–3) and 2) late nursery (period 4). Pens were randomly assigned to a sequence (period 1–3) in a crossover experimental design containing three 10-d periods, with 5 d for the resetting of baseline where unmedicated water was provided followed by 5 d on tiamulin source addition [i.e., TriamuloxTM (Zoetis, Parsippany, NJ); Denagard (Elanco Animal Health, Greenfield, IN)] or unmedicated water. After period 3 was concluded, all pens were given unmedicated water (via nipple waterers) and the number of pigs per pen was reduced to six pigs to maintain adequate space per pig. Ten days prior to pigs leaving the nursery, a fourth period was performed. After a 5-d water baseline was achieved, pens were treated with either unmedicated water or Triamulox- or Denagard-containing water. Pigs had ad libitum access to water and feed. During the testing periods, daily water intake was measured by a cup water system in each pen. Feed intake was measured every 5 d. There was no effect of treatment on initial body weights or weights at the beginning or end of each period (P ≥ 0.51). Therefore, there was no effect of treatment on ADG (P ≥ 0.23). Water intake (P ≥ 0.16) and FE (P ≥ 0.35) were not affected by treatment. Water consumption was similar among all treatments in each of the four periods. There appears to be no aversion to water intake when tiamulin hydrogen fumarate is added to the drinking water.