Intercorrelation among soil properties can result in multicollinearity problems regarding relationships between soil properties and crop yield. The objective of this study was to compare statistical ...methods of examining relationships between cotton (Gossypium hirsutum L.) yield, quality, and soil properties. Soil and plant samples were collected from 1-ha grids on an irrigated production cotton field in Texas from 1998 through 2000. Ordinary least square regression (OLS), partial least square regression (PLS), and principal component regression (PCR) were compared as methods for quantifying relationships between cotton yield or quality and soil properties. The PLS method eliminated multicollinearity problems and resulted in the coefficient estimations with meaningful signs compared with their associations to cotton yield and fiber quality. Furthermore, loadings from linear combinations of variables in PLS allowed identifying soil properties that had the greatest influence on yield. While PCR identified the principal components that maximized the variance of independent variables, it did not improve the modeling of crop-soil relationships. Among the selected soil and landscape properties, sand and clay content, exchangeable Ca(2+) and Mg(2+), NO3(-), Olsen-P, pH, relative elevation, and slope were important factors affecting lint yield and fiber quality. Higher lint yields were usually accompanied by higher fiber quality. Magnitudes of influence of different soil properties on yield and quality, however, varied among the 3 yr, suggesting that long-term studies are needed to establish robust relationships for site-specific management.
The Bryum bicolor complex includes four species in North America: B. bicolor, B. gemmilucens, B. gemmiferum, and B. barnesii. Bulbil morphology is the most important taxonomic character for ...delineating the four North American species recognized, but care must be taken not to confuse them with morphologically similar restricted buds produced by other Bryum species. Bryum bicolor is the only northern hemisphere species of the complex with bulbils single per leaf axil, but is sometimes considered to be identical with the southern hemisphere species, B. dichotomum. After examination of the North American herbarium material and the types of B. bicolor and B. dichotomum, we could not perceive morphological differences between the two species. However, our survey did not include any other southern hemisphere specimens and we therefore kept the name B. bicolor pending for further studies on the variability of the species of the complex in the southern hemisphere. Bryum barnesii, B. gemmiferum, and B. gemmilucens all produce many bulbils per leaf axil but differ in bulbil color, shape. and size. Bryum gemmilucens is characterized by 100–200 μm long yellow, orange or red bulbils; B. barnesii by usually larger, 200–450 μm long greenish bulbils with broad, obtuse to largely acute primordia; and B. gemmiferum by 150–350 (450) μm long, yellow green, rarely brownish bulbils with tooth-like primordia. Leaf morphology is too variable to be used as a reliable taxonomic character within the complex. Costa length is quite variable, and plants exhibiting large bulbils and strongly excurrent costa approach B. dunense, considered to be a synonym of B. bicolor. Similarily, plants with broad leaves and laminal cells approach B. balticum, considered to be conspecific with B. barnesii. Bryum bicolor has been reported from 25 states of the United States and six Canadian provinces. Bryum barnesii, newly reported from North America, is most common along the Pacific coast, whereas both B. gemmiferum and B. gemmilucens are considered rare in North America.
ABSTRACT
Land application of biosolids is a beneficial‐use practice whose ecological effects depend in part on hydrological effects. Biosolids were surface‐applied to square 0.5‐m2 plots at four ...rates (0, 7, 34, and 90 dry Mg ha−1) on each of three soil–cover combinations in Chihuahuan Desert grassland and shrubland. Infiltration and erosion were measured during two seasons for three biosolids post‐application ages. Infiltration was measured during eight periods of a 30‐min simulated rain. Biosolids application affected infiltration rate, cumulative infiltration, and erosion. Infiltration increased with increasing biosolids application rate. Application of biosolids at 90 dry Mg ha−1 increased steady‐state infiltration rate by 1.9 to 7.9 cm h−1 Most of the measured differences in runoff among biosolids application rates were too large to be the result of interception losses and/or increased hydraulic gradient due to increased roughness. Soil erosion was reduced by the application of biosolids; however, the extent of reduction in erosion depended on the initial erodibility of the site. Typically, the greatest marginal reductions in erosion were achieved at the lower biosolids application rates (7 and 34 dry Mg ha−1); the difference in erosion between 34 and 90 dry Mg ha−1 biosolids application rates was not significant. Surface application of biosolids has important hydrological consequences on runoff and soil erosion in desert grasslands that depend on the rate of biosolids applied, and the site and biosolids characteristics.
A new species in the formerly monotypic genus Vitalianthus is described from Amazonas State, Brazil. Vitalianthus urubuensis sp. n. exhibits leaves with an unbroken chain of ocelli, upright ...orientation of the underleaf lobes, and a 4-keeled perianth lacking horn-like projections; all features that distinguish the only other known member of this genus, V. bischleriana (Porto & Grolle) R. M. Schust. & Giancotti. Differences between V. urubuensis and V. bischleriana are most evident in leaf and lobule morphology. The discovery of this new species in central Amazonia dramatically expands the geographic range of Vitalianthus, a taxon once considered endemic to the coastal rainforests of northeastern Brazil.
A series of macrocyclic 3-aminopyrrolidinone farnesyltransferase inhibitors (FTIs) has been synthesized. Compared with previously described linear 3-aminopyrrolidinone FTIs such as compound 1, ...macrocycles such as 49 combined improved pharmacokinetic properties with a reduced potential for side effects. In dogs, oral bioavailability was good to excellent, and increases in plasma half-life were due to attenuated clearance. It was observed that in vivo clearance correlated with the flexibility of the molecules and this concept proved useful in the design of FTIs that exhibited low clearance, such as FTI 78. X-ray crystal structures of compounds 49 and 66 complexed with farnesyltransferase (FTase)-farnesyl diphosphate (FPP) were determined, and they provide details of the key interactions in such ternary complexes. Optimization of this 3-aminopyrrolidinone series of compounds led to significant increases in potency, providing 83 and 85, the most potent inhibitors of FTase in cells described to date.
A multistate cooperative study was conducted to study the current issue of tail length in docked lambs and its relationship to incidence of rectal prolapse. A total of 1,227 lambs at six locations ...were randomly allocated to two or three tail dock treatments: 1) short—tail was removed as close to the body as possible, 2) medium—tail was removed at a location midway between the attachment of the tail to the body and the attachment of the caudal folds to the tail, and 3) long—tail was removed at the attachment of the caudal folds to the tail. Short-docked lambs had a greater (P < 0.05) incidence of rectal prolapse (7.8%) than lambs with a medium (4.0%) or a long (1.8%) dock. Female lambs had a higher (P < 0.05) incidence of rectal prolapse than male lambs. At two stations, lambs were finished either in a feedlot on a high-concentrate diet or on pasture with no grain supplementation. At one station, with a very low incidence of rectal prolapse, there was no difference in incidence between lambs finished in the feedlot or on pasture; however, at the station with a relatively high incidence of rectal prolapse, lambs in the feedlot had a higher (P < 0.05) incidence than lambs on pasture. The half-sib estimate of heritability for the incidence of rectal prolapse was low (0.14). The results of this study strongly implicate short dock length as a cause of rectal prolapse in lambs finished on high-concentrate diets. Furthermore, the results of this study and the only other study known conducted on this issue strongly suggest that docking lambs at the site of the attachment of the caudal folds to the tail will result in a negligible incidence of rectal prolapse.
Compost derived from landscape debris was incorporated into seven different soils in the Dallas, Texas area at variable rates. Treatment levels for each of the 3.34 m
2
quadrats were compost depths ...of approximately 0.0, 2.5, 5.0 and 7.5 cm. Composted plots were evaluated for two years to quantify differences in infiltration rate, moisture content, coefficient of linear extensibility (COLE), pH and salinity relative to control plots. Substantial differences in soil properties between sites barred comparison between sites. However, significant site-specific differences between control and treatments were observed. Infiltration rate was more strongly affected by soil texture, soil mineralogy, and climatic effects than by the addition of compost. Compost incorporation may provide a significant reduction in COLE values, but not necessarily to levels below the "very high" shrink/swell class. Soil water content significantly increased with elevated levels of compost in the Austin, Eddy, and Brackett soils. Incorporated landscape compost does provide quantifiable benefits to soil physical properties on certain soil series in the Dallas area.
A modern massive Porites coral was collected from the Longwan Bay (19°20′N, 110°39′E) on the east coast of the Hainan Island, China. The coral was sectioned vertical to the growth axis into discs of ...double density-bands representing annual growth. The samples were analyzed for the Sr/Ca ratio by inductively coupled plasma atomic emission spectrometry. The history of winter sea-surface temperature (SST) is reconstructed using the Sr/Ca ratio in winter bands of corals. The winter SST at Xisha in the middle of the South China Sea (SCS) is weakly correlated with the instrument-measured winter monsoon velocity (WMV) with a correlation coefficient of 0.19. The winter SST data from corals at Longwan Bay, Hainan, in the northern SCS are moderately correlated with the WMV (
r
=
0.40). Interestingly we found that the difference of winter SSTs between the two sites (Xisha and Longwan Bay, Hainan) (the
X–
H index) is significantly negatively correlated with the WMV (
r
=
−
0.73). This negative correlation may be related to the intrusion of the warm Kuroshio Current into the SCS through the Luzon Strait promoted by the strong northeastern monsoon winds in the winter. Using the relationship between our coralline data and observed WMV, the calculated winter monsoon velocity (WMVc) was obtained for 87 years. This data set in combination with the instrument-measured data between 1993 and 1998 generate a record of WMVc for a period of 93 years from 1906 to 1998. The WMVc in the 20th century shows significant interannual and decadal variability with a trend of persistent decline in the whole 20th century at the rate of decrease of −
0.02 (m/s)/a. The lowest wind velocity occurred during the last two decades of the 20th century. The WMVc has decreased significantly by about 30% from the early to the late of 20th century. The 20th century decline of winter monsoon velocity evidenced from the SCS coral records is consistent with the atmosphere–ocean general circulation models (AOGCMs) simulations for monsoon response to increasing temperatures. In addition, an obvious decline shift of WMV around 1976 can be seen in both instrumental and proxy records and it coincides with many other Pacific records. This shift is likely to correspond to a Pacific-wide change in the Pacific Decadal Oscillation occurring at the same time.
