Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity,plant nutrition,and chemical characteristics of soil

Treated industrial effluents have high levels of nutrients and dissolved organic matter. The irrigation of rice by flooding can increase nutrient uptake and grain yield. Therefore, this study evaluated the nutrient contents in the shoots and grain of the rice crop and also the chemical of the soil after irrigation of the crop with leachate of the treated industrial effluent. A greenhouse experiment was conducted using pots filled with 20 kg of soil in a randomized block design with three replications. The treatments consisted of control (irrigation with distilled water) and four concentrations of the leachate (25, 50, 75, and 100 %) for irrigation. At the end of the experiment, the nutrient contents in tissues of rice plants, sterility of spikelets, and grain mass were evaluated. Results showed that irrigation with the leachate at 25 % content increased the macro- and micronutrients’ concentrations in the shoot biomass and grain, except for potassium and iron. Irrigation with the industrial leachate decreased tillering and grain yield; however, it increased chlorophyll content, sterility of spikelets, and sodium intake at this leachate concentration. The potassium and sodium levels and the electrical conductivity values of soils irrigated with treated industrial leachate were increased. The use of the treated leachate from industrial effluents is an alternative that reuses the nutritional load, but the volume of leachate should be limited and monitored to prevent the sodicity in the soil and problemsdue to eutrophication.     

Pharmacokinetics of xylazine after 2-, 4-, and 6-hr durations of continuous rate infusions in horses

Intravenous (i.v.) bolus administration of xylazine (XYL) (0.5 mg/kg) immediately followed by a continuous rate infusion (CRI) of 1 mg kg⁻¹ hr⁻¹ for 2, 4, and 6 hr produced immediate sedation, which lasted throughout the duration of the CRI. Heart rate decreased and blood pressure increased significantly (p > .05) in all horses during the first 15 min of infusion, both returned to and then remained at baseline during the duration of the infusion. Compartmental models were used to investigate the pharmacokinetics of XYL administration. Plasma concentration–time curves following bolus and CRI were best described by a one-compartment model. No differences were found between pharmacokinetic estimates of the CRIs for the fractional elimination rate constant (K_e), half-life (t_1/2e), volume of distribution (V_d), and clearance (Cl). Median and range were 0.42 (0.15–0.97)/hr, 1.68 (0.87–4.52) hr, 5.85 (2.10–19.34) L/kg, and 28.7 (19.6–39.5) ml min⁻¹ kg⁻¹, respectively. Significant differences were seen for area under the curve ( ) (p < .0002) and maximum concentration (C_max) (p < .04). This indicates that with increasing duration of infusion, XYL may not accumulate in a clinically relevant way and hence no adjustments are required in a longer XYL CRI to maintain a constant level of sedation and a rapid recovery.     

One-day rate measurements for estimating net nitrification potential in humid forest soils

Measurements of net nitrification rates in forest soils have usually been performed by extended sample incubation (2–8 weeks), either in the field or in the lab. Because of disturbance effects, these measurements are only estimates of nitrification potential and shorter incubations may suffice. In three separate studies of northeastern USA forest soil surface horizons, we found that laboratory nitrification rates measured over 1 day related well to those measured over 4 weeks. Soil samples of Oa or A horizons were mixed by hand and the initial extraction of subsamples, using 2 mol L⁻¹ KCl, occurred in the field as soon as feasible after sampling. Soils were kept near field temperature and subsampled again the following day in the laboratory. Rates measured by this method were about three times higher than the 4-week rates. Variability in measured rates was similar over either incubation period. Because NO₃⁻ concentrations were usually quite low in the field, average rates from 10 research watersheds could be estimated with only a single, 1-day extraction. Methodological studies showed that the concentration of NH₄⁺ increased slowly during contact time with the KCl extractant and, thus, this contact time should be kept similar during the procedure. This method allows a large number of samples to be rapidly assessed.     

The influence of regulatory forest policy tools on biodiversity measures for forests in Ukraine

The transition from a state-oriented forest economy to a market-oriented one requires a critical analysis of the set of tools designed to implement state forest policies. One of the important goals of Ukrainian forest policy is conservation of the biodiversity of forest ecosystems. This paper analyzes the influence of two of the regulatory forest policy instruments (zoning and prohibition of final harvesting) on the diversity of woody vegetation using Tobit regression. Data on the forest resources of the Sumy administrative province in Ukraine are used for the analysis. Additionally, we look at how diversity of woody vegetation is affected by the form of forest tenure.     

Agroforestry practices of non-industrial private forest landowners in Washington State

A mail survey was conducted to gain understanding of the agroforestry practices of non-industrial private forest landowners (NIPF) in Washington State, located in the north-western USA. Although NIPF owners control 1.5 million hectares of the state's commercial forestland base, their diversity of forestland uses, land management practices and objectives as land managers are not well understood. Past NIPF surveys and anecdotal information suggest agroforestry is a major use of NIPF lands. We defined agroforestry as a potentially sustainable land use practice combining the deliberate growing of woody perennials with agricultural crops and/or animals. Objectives of this study were to:

1. determine the extent that agroforestry is used by Washington's NIPF owners,
2. develop insight into NIPF owners' motivations for practicing agroforestry,
3. describe the agroforestry practices within three distinct physiographic and agroecological zones in Washington, and
4. determine the agroforestry information needs of NIPF owners.

The target population consisted of NIPF owners in 4 counties within each of the three regions. Response to the August 1990 mail survey was 63.5%, yielding 296 useable questionnaires. Fifty-seven percent of all respondents practice agroforestry. Forestland grazing is the most common agroforestry practice (39% of all respondents), followed by windbreaks (34%), harvest of special forest products (12%), livestock enrichment plantings for forage or shelter (7%), orchard grazing (5%), orchard intercropping (2%), and Christmas tree grazing (0.34%). The most frequent motives for owning land were passing land on to children (80%), keeping it natural and income from timber (both 72%). Respondents saw aesthetics (77%), increasing land unit income (74%), and water conservation (70%) as possible advantages of practicing agroforestry. High establishment costs (66%) and livestock damage to trees or crops (64%) were the most frequently selected potential disadvantages to practicing agroforestry. Lack of technical and educational support (67%) and lack of access to livestock/livestock facilities (58%) were disincentives to practicing agroforestry. Landowners are interested in learning more about agroforestry and how agroforestry techniques might be incorporated in their land management tool kit. A significant number of non-industrial private forest land owners in Washington believe that management of forestland, balancing conservation and production goals, can be furthered by suitable agroforestry practices.     

Mapping the territory: agroforestry awareness among Washington State land managers

There is growing interest in research to develop potential agroforestry models for temperate climates. In Washington State, recent studies and anecdotal information suggest that agroforestry is already employed by land managers, and if so, this experience should inform future research efforts. Because this population is not well defined, a mail survey was designed to: 1) Assess Washington land manager awareness of agroforestry, 2) assess perceptions of agroforestry as a land management tool, 3) assess the perceived potential opportunities or obstacles for land managers to practice agroforestry, and 4) identify landowner groups believed to be practicing agroforestry in Washington State.Three groups of land managers were surveyed: employees of the Soil Conservation Service (SCS), Washington State University Cooperative Extension Service (WSUCE) and OTHER, consisting of university faculty, private land managers, State and Federal land managers and owners of small natural resource businesses.Agroforestry was not a new concept for most (94%) respondents, further 55% of those familiar with agroforestry were practicing agroforestry or providing advice to landowners who were practicing agroforestry. Use in (government mandated) soil conservation plans on farmland (100% of all respondents) was the most frequently cited potential application for agroforestry in the state followed by range and pasture land and managing non-commercial forest land (both 84%), use on commercial forest plantation (83%) and fruit and nut orchards (61%).Diversifies land use (25%), enhanced productivity (18%), aesthetics (13%) and income diversity (13%) were the four most frequently cited potential advantages to practicing agroforestry. Lack of information (28%), lack of technical assistance (18%), establishment costs (14%) and not an established practice (14%) were the most frequently identified potential obstacles to practicing agroforestry. Respondents suggested there is great potential for application of agroforestry throughout the state, and non-industrial private forest land owners were selected for future study of this potential.     

Effects of dietary carbohydrate on weight gain and gonad production in small sea urchins,Lytechinus variegatus

In experiment 1, juvenile sea urchins (n = 80, 0.088 ± 0.001 g wet weight and 5.72 ± 0.04 mm diameter) were held individually and fed ad libitum one of three semi‐purified formulated diets (n = 16 individuals treatment^?1). In the diets, protein was held constant (310 g kg^?1 dry, as fed) and carbohydrate level varied (190, 260, or 380 g kg^?1 dry, as fed). Wet weights were measured every 2 weeks. Total wet weight gain was inversely proportional to dietary carbohydrate level and energy content of the respective diet. In experiment 2, sea urchins (5.60 ± 0.48 g wet weight, n = 40) fed 190 g kg^?1 carbohydrate consumed significantly more dry feed than those fed 260 g kg^?1, but not more than those fed 380 g kg^?1 carbohydrate. Based on differential feed intake rates, sea urchins that consumed more feed also consumed higher levels of protein and had the highest weight gain. Consequently, protein content and/or protein: energy ratio may be important in determining feed utilization and growth among sea urchins in this study. The average digestible energy intake was approximately 70 kcal kg^?1 body weight day^?1, suggesting daily caloric intake of juvenile Lytechinus variegatus is lower than in shrimp and fish.     

Amplification of the <Emphasis Type="Italic">Phytophthora infestans</Emphasis> RG57 loci Facilitates <Emphasis Type="Italic">in planta</Emphasis> T-RFLP Identification of Late Blight Genotypes

Late blight, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a devastating disease in potato and tomato and causes yield and quality losses worldwide. The disease first emerged in central America and has since spread in North America including the United States and Canada. Several new genotypes of P. infestans have recently emerged, including US-22, US-23 and US-24. Due to significant economic and environmental impacts, there has been an increasing interest in the rapid identification of P. infestans genotypes. In addition to providing details regarding the various phenotypic characteristics such as fungicide resistance, host preference, and pathogenicity associated with various P. infestans genotypes, information related to pathogen movement and potential recombination may also be determined from the genetic analyses. Restriction fragment length polymorphism (RFLP) analysis with the RG57 loci is one of the most reliable procedures used to genotype P. infestans. However, the RFLP procedure requires propagation and isolation of the pathogen and relatively large amounts of DNA. Isolation of the late blight pathogen is sometimes impossible due to the poor condition of the infected tissues or the presence of fungicide residues. In this study, we describe a procedure to identify P. infestans at the molecular level in planta using terminal restriction fragment length polymorphism (T-RFLP) of the RG57 loci. This T-RFLP assay is sufficiently sensitive to detect and differentiate P. infestans genotypes directly in planta without propagation and isolation of the pathogen, to facilitate the timely implementation of best management practices.     

Role of basidiomycete fungi in the grapevine trunk disease esca

Phaeomoniella chlamydospora and wood-rotting basidiomycete fungi, namely Fomitiporia spp., are known esca pathogens. However, the effect of their mixed infections and the sequence of infection on disease development is unclear. To determine the effects of single and co-inoculations on symptoms, potted Vitis vinifera ‘Crimson Seedless’ was inoculated with P. chlamydospora either alone or in combination with one of four basidiomycetes: Coprinellus radians, Fomitiporia langloisii, F. polymorpha and the novel species Tropicoporus texanus. Basidiomycetes were isolated from vines with foliar symptoms of esca in California and Texas. In sequential co-inoculations, the effects of different sequences of infection (P. chlamydospora first, basidiomycete 6 months later; and vice versa) were tested, compared to simultaneous co-inoculations. Plants inoculated with P. chlamydospora either alone or in combination with a basidiomycete (in any sequence) did not differ significantly in the length of black-streaking lesions. In plants inoculated only with a basidiomycete, the appearance of large brown lesions, coupled with the absence of this wood symptom from control plants, suggests that C. radians, F. langloisii and T. texanus are pathogenic. Foliar symptoms resembling those of esca in the field (marginal and/or interveinal scorching, combined with red and/or yellow discoloration) were statistically more frequent among plants inoculated with F. polymorpha or T. texanus, either simultaneously or following P. chlamydospora, compared to single inoculations. Sequential co-inoculations of a basidiomycete before or after P. chlamydospora were associated with similar lesion lengths, suggesting that basidiomycetes may not require infection by P. chlamydospora in order to extensively colonize the wood.