Inter-relation between soybean yield and soil compaction under degraded pasture in Brazilian Savannah

The Cerrado (Brazilian Savannah) plays an important economic and financial role in the nation, since the pastures of this biome feed cattle for half of the domestic bovine meat productivity, and its agricultural fields produce a third of the country's grain. The variability and spatial dependence between the soil physical attributes and soybean yield were evaluated in a crop rotation planted on a degraded brachiaria pasture, on a dystroferric Red Latosol of an experimental farm of the State University of São Paulo (UNESP), in the 2005/2006 growing season. The linear and spatial correlations between these attributes were also studied, to determine conditions that would allow increased agricultural productivity. In the above pasture area, a grid was installed with 124 plots, spaced 10.0 x 10.0 m and 5.0 x 5.0 m apart, in a total area of 7,500 m². From the linear and spatial point of view, the high grain yield can be explained by the number of grains per plant and soil macroporosity. The high variability observed for most soil properties indicated that the crop - livestock integration system results in environmental heterogeneity of the soil.

Soil fauna as an indicator of soil quality in forest stands, pasture and secondary forest

The interactions between soil invertebrates and environmental variations are relatively unknown in the assessment of soil quality. The objective of this study was to evaluate soil quality in areas with different soil management systems, based on soil fauna as indicator, in Além Paraíba, Minas Gerais, Brazil. The soil invertebrate community was sampled using pitfall traps, in the dry and rainy seasons, from areas with five vegetation types (acacia, mimosa, eucalyptus, pasture, and secondary forest). The abundance of organisms and the total and average richness, Shannon's diversity index, the Pielou uniformity index, and change index V were determined. The fauna was most abundant in the areas of secondary forest and mimosa plantations in the dry season (111.3 and 31.7 individuals per trap per day, respectively). In the rainy season, the abundance of organisms in the three vegetation types did not differ. The highest values of average and total richness were recorded in the secondary forest in the dry season and in the mimosa stand in the rainy season. Shannon's index ranged from 1.57 in areas with acacia and eucalyptus in the rainy season to 3.19 in the eucalyptus area in the dry season. The uniformity index was highest in forest stands (eucalyptus, acacia and mimosa) in the dry season, but higher in the rainy season in the pasture and secondary forest than in the forest stands. The change index V indicated that the percentage of extremely inhibited groups was lowest in the area with mimosa, both in the dry and rainy season (36 and 23 %, respectively). Of all forest stands, the mimosa area had the most abundant soil fauna.

Physical properties of a Red-Yellow Latosol and productivity of a signalgrass pasture fertilized with increasing nitrogen doses

The physical properties and fertility of the soil are important factors in the formation and establishment of pasture. Changes in physical properties affect the movement of water, air, nutrients and roots, which, in turn, affect the productivity and longevity of pastures. The objective of this study was to evaluate the physical properties of the soil and the dry matter yield of a pasture with signalgrass cv. Basilisk (Brachiaria decumbens cv. Basilisk), fertilized with increasing nitrogen doses (N), on a dystrophic Red-Yellow Latosol. The experiment was conducted on the Fazenda Rio Manso of the Universidade Federal dos Vales do Jequitinhonha e Mucuri, in Couto de Magalhães de Minas, State of Minas Gerais, Brazil. To evaluate the annual forage yield, a split plot scheme in a randomized block design with four replications was used, with N doses (0, 50, 100, 150, and 200 kg/ha/year) in the plots and growing seasons (first and second) in the subplots. For soil evaluation, a split plot scheme was used with N doses (0, 25, 50, 75 and 100 kg/ha/cut) in the plots and three sampling times (prior to the experiment, at the end of the first growing season and at the end of the second growing season) in the subplots in a randomized block design with four replications. This analysis was performed separately at two soil depths (0-3 and 10-13 cm). Forage samples were analyzed for the annual dry matter yield (DMY), and soil samples were analyzed for pre-consolidation pressure (σp), initial soil bulk density (Bd), total pore volume (TPV) and void index (Vd). Higher nitrogen doses increased the dry matter yield of signalgrass pasture and the pre-consolidation pressure of the soil. The total pore volume and void index decreased, and the initial soil bulk density increased, though without promoting soil compaction.

Sheep Excreta as Source of Nitrous Oxide in Ryegrass Pasture in Southern Brazil

ABSTRACT Livestock urine and dung are important components of the N cycle in pastures, but little information on its effect on soil nitrous oxide (N2O) emissions is available. We conducted a short-term (39-day) trial to quantify the direct N2O-N emissions from sheep excreta on an experimental area of ryegrass pasture growing on a Typic Paleudult in southern Brazil. Four rates of urine-N (161, 242, 323, and 403 kg ha-1 N) and one of dung-N (13 kg ha-1 N) were applied, as well as a control plot receiving no excreta. The N2O-N emission factor (EF = % of added N released as N2O-N) for urine and dung was calculated, taking into account the N2O fluxes in the field, over a period of 39 days. The EF value of the urine and dung was used to estimate the emissions of N2O-N over a 90-day period of pasture in the winter under two grazing intensities (2.5 or 5.0 times the herbage intake potential of grazing lambs). The soil N2O-N fluxes ranged from 4 to 353 µg m-2h-1. The highest N2O-N fluxes occurred 16 days after application of urine and dung, when the highest soil nitrate content was also recorded and the water-filled pore space exceeded 60 %. The mean EF for urine was 0.25 % of applied N, much higher than that for dung (0.06 %). We found that N2O-N emissions for the 90-day winter pasture period were 0.54 kg ha-1 for low grazing intensity and 0.62 kg ha-1 for moderate grazing intensity. Comparison of the two forms of excreta show that urine was the main contributor to N2O-N emissions (mean of 36 %), whereas dung was responsible for less than 0.1 % of total soil N2O-N emissions.

Relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture

The objective of this work was to assess the relationship between macrofauna, mineralogy and exchangeable calcium and magnesium in Cerrado Oxisols under pasture. Twelve collection points were chosen in the Distrito Federal and in Formosa municipality, Goiás state, Brazil, representing four soil groups with varied levels of calcium + magnesium and kaolinite/(kaolinite + gibbsite) ratios. Soil macrofauna was collected in triplicate at each collection point, and identified at the level of taxonomic groups. Macrofauna density showed correlation with contents of kaolinite, gibbsite and exchangeable Ca + Mg in the soils. Mineralogy and exchangeable Ca + Mg had significant effects on taxonomic groups and relative density of soil macrofauna. The termites (Isoptera) were more abundant in soils with low exchangeable Ca + Mg; earthworms (Oligochaeta), in soils with high levels of kaolinite; and Hemiptera and Coleoptera larvae were more abundant in gibbsitic soils with higher contents of total carbon.

09032-017 Miller Creek Watershed Final Report

Miller Creek is on the 2006 Section 303d Impaired Waters List and has a 19,926 acre watershed. All indicators, as reported in the Miller Creek assessment, show that the impairment is due to sediment and nutrient delivery from upland runoff which contributes to elevated water temperatures, excessive algae, and low dissolved oxygen levels within the stream. In an effort to control these problems, the Miller Creek Water Quality Project will target areas of 5 tons per acre or greater soil loss or with 0.5 tons per acre or greater sediment delivery rates. The assessment revealed these targeted priority lands make up 32% or 6,395 acres of the Miller Creek watershed. Priority lands include cropland, pasture land, timber, and sensitive riparian areas. It is the goal of this project to reduce sediment delivery by 70% on 60% or 3,837 acres of these priority lands. This will be accomplished through installation of strategically placed structural practices, rotational grazing systems, and buffer strips. These practices will reduce soil loss, reduce sediment delivery, improve water quality, and improve wildlife habitat in the watershed. Utilizing partnerships with NRCS and IDALS-DSC will be important in making this project successful. In addition to using matching funds from EQIP, WHIP, and CRP, the Monroe SWCD is committed to prioritizing local cost share funds through IFIP and REAP for use in the Miller Creek Watershed.

Dimorphic turning bias in spontaneous rotational movement

Turning biases have been associated with unbalanced hemispheric dopaminergic activity, and this activity has been correlated with cue-directed behaviors. Moreover, a sexual differentiation in hippocampal dopaminergic receptors following learning has been shown. In humans, pointing responses towards the starting point is commonly used to assess the accuracy of direction estimation after locomotion. Thus, it may be of interest for the field of spatial cognition to explore human sex differences in spontaneous turning bias when a body rotation is required. To this end, male and female blindfolded subjects were guided in a linear displacement and asked to rotate in order to point in the direction of the starting position. The main finding was a massive difference between men and women. 80% of women showed a turning bias to the right when 69% of men showed a bias to the left. Moreover, these preferences were not correlated with handedness. These results suggest basic preferences associated to sex might influence male and female performance in spatial cognition. They also suggest experimental procedures may be biased in favor of male or female strategies. Therefore, such preferences should be considered in order to gain further insight into the development of more balanced procedures.

Sward and milk production response to early turnout of dairy cows to pasture in Finland

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Winter pasture and cover crops and their effects on soil and summer grain crops

The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization (oilseed radish); and natural vegetation, without grazing and nitrogen fertilization (fallow). Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.

Microbial communities in Cerrado soils under native vegetation subjected to prescribed fire and under pasture

The objective of this work was to evaluate the effects of fire regimes and vegetation cover on the structure and dynamics of soil microbial communities, through phospholipid fatty acid (PLFA) analysis. Comparisons were made between native areas with different woody covers ("cerrado stricto sensu" and "campo sujo"), under different fire regimes, and a 20-year-old active palisadegrass pasture in the Central Plateau of Brazil. Microbial biomass was higher in the native plots than in the pasture, and the highest monthly values were observed during the rainy season in the native plots. No significant differences were observed between fire regimes or between communities from the two native vegetation types. However, the principal component (PC) analysis separated the microbial communities by vegetation cover (native x pasture) and season (wet x dry), accounting for 45.8% (PC1 and PC3) and 25.6% (PC2 and PC3), respectively, of the total PLFA variability. Changes in land cover and seasonal rainfall in Cerrado ecosystems have significant effects on the total density of soil microorganisms and on the abundance of microbial groups, especially Gram-negative and Gram-positive bacteria.

Foraging behavior and ruminal fermentation of dairy cows grazing ryegrass pasture alone or with white clover

The objective of this work was to evaluate the influence of pasture composition and regrowth age on the relationship between feeding behavior and ruminal fermentation in dairy cows grazing perennial ryegrass with or without white clover. The experiment was carried out in a 2x2 factorial arrangement, with two sward types and two ages of regrowth. Swards of perennial ryegrass sown alone (PRG) and of perennial ryegrass mixed with white clover (GC) were evaluated. Twelve late-lactation Holstein cows, fistulated at the rumen, were distributed in a 4x4 latin square experimental design with four 12-day periods. Daily distribution of grazing was similar in the PRG and the GC swards, but the concentration of rumen volatile fatty acids (VFA) was higher and the proportion of propionate was lower on mixed swards during the day. Daily distribution of grazing was similar in pastures of different ages. However, in the oldest swards, rumen fluid pH increased and VFA concentration decreased after evening milking. Time spent grazing does not influence ruminal fermentation, which depends on the changes that occur as different sward layers are grazed.

Forage production of elephant grass under intermittent stocking

The objective of this work was to evaluate the dry matter production of elephant grass (Pennisetum purpureum) genotypes, managed under intermittent stocking. A completely randomized design was used, with two genotypes and three replicates. The treatments consisted of factorial combinations (2x2x2) of genotypes ('BRS Kurumi' and the clone CNPGL 00‑1‑3), two light interception levels (LI) at the onset of grazing (90 and 95%), and two post‑grazing canopy heights (30 and 50 cm). A total of 24 Holstein x Zebu crossbred heifers were used. The stocking density varied in order to finish the grazing periods in two days. The interval between the defoliation, based on 95% LI, resulted in a higher leaf mass per grazing cycle. The post‑grazing height of 30 cm did not affect the number of grazing cycles but provided a greater herbage accumulation rate. The cultivar BRS Kurumi has higher pasture growth, lower rest period, and greater number of grazing cycles, which results in increased forage production in the growing season.

Meat lipid profile of steers finished in pearl millet pasture with different rates of concentrate

The objective of this work was to evaluate the meat lipid profile from Devon beef steers finished in pearl millet (Pennisetum americanum) pasture and fed at different rates of concentrate supplementary diet. Twelve steers weighing 270 kg, at 12‑month‑average initial age, were randomly distributed into three treatments: pearl millet pasture; and pearl millet pasture plus a concentrate equivalent at 0.5 or 1.0% of body weight, with two replicates. Total contents of saturated and unsaturated fatty acids, the polyunsaturated:saturated ratio and other relevant fatty acids as the vaccenic acid, conjugated linoleic acid, omega‑3, and omega‑6 were not affected by the consumption of a concentrate supplement at 0.5 or 1.0% live weight. However, the 0.5% supplementation level reduced the concentration of dihomo‑γ‑linolenic fatty acid (C20: 3 n‑6), while the 1.0% supplementation level elevated the content of docosahexaenoic (DHA) (C22: 6 n‑3) fatty acid, and the omega‑6:omega‑3 ratio in meat. Consumption of up to 1.0% energy supplementation increases the omega‑6:omega‑3 ratio in meat from Devon steers grazing on pearl millet pasture.

Rotational Doppler effect in magnetic resonance

We compute the shift in the frequency of the spin resonance in a solid that rotates in the field of a circularly polarized electromagnetic wave. Electron-spin resonance, nuclear magnetic resonance, and ferromagnetic resonance are considered. We show that contrary to the case of the rotating LC circuit, the shift in the frequency of the spin resonance has strong dependence on the symmetry of the receiver. The shift due to rotation occurs only when rotational symmetry is broken by the anisotropy of the gyromagnetic tensor, by the shape of the body or by magnetocrystalline anisotropy. General expressions for the resonance frequency and power absorption are derived and implications for experiment are discussed.

BioSuper: A web tool for the superimposition of biomolecules and assemblies with rotational symmetry

Background Most of the proteins in the Protein Data Bank (PDB) are oligomeric complexes consisting of two or more subunits that associate by rotational or helical symmetries. Despite the myriad of superimposition tools in the literature, we could not find any able to account for rotational symmetry and display the graphical results in the web browser. Results BioSuper is a free web server that superimposes and calculates the root mean square deviation (RMSD) of protein complexes displaying rotational symmetry. To the best of our knowledge, BioSuper is the first tool of its kind that provides immediate interactive visualization of the graphical results in the browser, biomolecule generator capabilities, different levels of atom selection, sequence-dependent and structure-based superimposition types, and is the only web tool that takes into account the equivalence of atoms in side chains displaying symmetry ambiguity. BioSuper uses ICM program functionality as a core for the superimpositions and displays the results as text, HTML tables and 3D interactive molecular objects that can be visualized in the browser or in Android and iOS platforms with a free plugin. Conclusions BioSuper is a fast and functional tool that allows for pairwise superimposition of proteins and assemblies displaying rotational symmetry. The web server was created after our own frustration when attempting to superimpose flexible oligomers. We strongly believe that its user-friendly and functional design will be of great interest for structural and computational biologists who need to superimpose oligomeric proteins (or any protein). BioSuper web server is freely available to all users at http://ablab.ucsd.edu/BioSuper webcite.