The Effect of MSW Compost and Fertilizer on Extractable Soil Elements, Tuber Yield, and Elemental Concentrations in the Plant Tissue of Potato

Municipal solid waste (MSW) compost is readily available in eastern Canada and may be a good source of fertility. A 3-year experiment evaluated the effects of MSW compost and fertilizer on soil fertility, elemental composition and yield of potato (Solanum tuberosum L.) grown in a sandy loam soil. Three rates of compost (MSW1, MSW2, and MSW3), one rate of fertilizer (NPK), and one mixture of 1/2 MSW1 compost and 1/2 NPK fertilizer were applied annually to plots in a three-crop rotation; each year the MSW1 rate attempted to match the rate of P applied in the NPK treatment. Mehlich-3 extracts were evaluated for 11 elements at two soil depths (0?C15 and 15?C30 cm). Potato shoots and roots or whole plants were assessed for 16 elements. Treatments had no consistent significant influence on marketable tuber yields although the NPK treatment produced mathematically the highest yields. After 3 years, treatments had influenced soil concentrations of K, Ca, S, Cu, Zn, and Na in Mehlich-3 extracts at the 0?C15 cm depth, but only the concentration of Na at the 15?C30 cm depth. The concentration of Mg in the plant tissue was consistently highest in plants fertilized with NPK; this treatment also produced higher Mn concentrations in the last 2 years. Shoot Cu concentrations were highest in the MSW3 plots. The compost did not increase heavy metal concentrations in shoot, root or whole-plant tissue and would be safe to use at agronomic rates of application.     

Genetic analysis of drought tolerance in adapted × exotic crosses of maize inbred lines under managed stress conditions

Introduced maize (Zea mays L.) germplasm can serve as sources of favorable alleles to enhance performance in new maize varieties and hybrids under drought stress conditions. In the present study, the combining abilities of 12 exotic maize inbred lines from CIMMYT and 12 adapted maize inbred lines from IITA were studied for grain yield and other traits under controlled drought stress. The inbred lines from each institution were separated into groups using SSR-based genetic diversity and were intercrossed using a factorial mating scheme to generate 96 hybrids. These hybrids were evaluated under both controlled drought stress and well-watered conditions at Ikenne in Nigeria in 2010 and 2011. Average mean yields of hybrids under drought stress represented 23 % of the average yield of hybrids under full irrigation. General combining ability (GCA) effects accounted for 49–85 % of the observed variation for several traits recorded under both well-watered and drought stress conditions. Specific combining ability effects for grain yield, though positive in most hybrids, were not significant under drought stress conditions. All the twelve exotic and nine adapted lines had positive GCA effects (female, male, or both) for grain yield under either drought stress or full irrigation, or both environments. EXL03 and EXL15 that had positive and significant female and male GCA effects for grain yield under both environments can be used to improve their adapted counterparts for grain yield and drought tolerance. Normalized difference vegetation index had weak but significant correlation with grain yield.     

Bioavailability of arginine from Indian mustard protein concentrate and meal compared with that of a soy protein concentrate in rainbow trout (Oncorhynchys mykiss)

Relative bioavailability (RBV) of arginine (Arg) from Indian mustard protein concentrate (IMC, 62% crude protein) and Indian mustard meal (IMM, 42% crude protein), and a commercially available soy protein concentrate (SPC, 57% crude protein) was compared with that of crystalline L‐arginine (L‐Arg) in rainbow trout. A basal diet highly deficient in Arg (1.23%) was formulated. Eight other isoproteic and isoenergetic diets were formulated to contain ~1.35% and ~1.5% Arg by adding increasing amount of IMC, IMM, SPC and L‐Arg. The experimental diets were fed for 16 weeks using a standard protocol. Growth rate, weight gain (g fish^?1) and protein (PD, g fish^?1) and lipid (LD, g fish^?1) deposition were increased linearly with increasing level of Arg from all ingredients. Arg availability from protein‐bound sources were equal or higher than those from L‐Arg. RBV of Arg from IMC, IMM and SPC were ranged from 100% and 123% than that from L‐Arg (assumed as 100% bio‐available). Among the ingredients, only the RBV of Arg from IMC was significantly higher than those from SPC (P < 0.05). The findings suggest that the RBV of Arg from IMC and IMM are very good and comparable to that of the commercial SPC used in this study.     

Genotypic variation in abscisic acid content,carbon isotope ratio and their relationship with cassava growth and yield under moisture stress and irrigation

This study was carried out to assess genotypic variability in abscisic acid content, carbon isotope ratio, and their relationship to storage root yield and yield components in cassava under irrigation and moisture stress. The study involved 20 cassava genotypes arranged in randomized complete block design with three replications. Irrigation water was applied using a drip irrigation system with a discharge rate of approximately 5.33 L m^-2 hr^-1. Significant (P < 0.05) genotypic variability was observed for all physiological, growth, and yield traits assessed. Abscisic acid content was higher under stress than irrigation and negatively correlated with root yield (r = -0.45), harvest index (r = -0.43), and above-ground biomass yield (r = -0.20) indicating that it can be used as indirect selection criteria against unproductive genotypes. Carbon isotope ratio was significantly and positively correlated with above-ground biomass yield (r = 0.20) but not root yield (r = 0.09). Estimates of genotypic variability indicated high values for most of the growth and yield components but low heritability values for abscisic acid content, carbon isotope ratio, stomatal conductance, and root yield under stress conditions. However, higher estimates were recorded under irrigation and in the combined analysis. It was also found from this study that carbon isotope ratio influences above-ground biomass but not storage root yield under stress conditions. The results from this study provide useful information on the relationship between abscisic acid content, carbon isotope discrimination, and storage root yield in field-grown cassava.     

Effects of carprofen, meloxicam and deracoxib on platelet function in dogs

ObjectiveTo determine effects of anti-inflammatory doses of COX-2 selective NSAIDs carprofen, meloxicam, and deracoxib on platelet function in dogs and urine 11-dehydro-thromboxane B2.Study designRandomized, blocked, crossover design with a 14-day washout period.AnimalsHealthy intact female Walker Hounds aged 1–6 years and weighing 20.5–24.2 kg.MethodsDogs were given NSAIDs for 7 days at recommended doses: carprofen (2.2 mg kg^?1, PO, every 12 hours), carprofen (4.4 mg kg^?1, PO, every 24 hours), meloxicam (0.2 mg kg^?1, PO, on the 1st day then 0.1 mg kg^?1, PO, every 24 hours), and deracoxib (2 mg kg^?1, PO, every 24 hours). Collagen/epinephrine and collagen/ADP PFA-100 cartridges were used to evaluate platelet function before and during and every other day after administration of each drug. Urine 11-dehydro-thromboxane B₂ was also measured before and during administration of each drug.ResultsAll NSAIDs significantly prolonged PFA-100 closure times when measured with collagen/epinephrine cartridges, but not with collagen/ADP cartridges. The average duration from drug cessation until return of closure times (collagen/epinephrine cartridges) to baseline values was 11.6, 10.6, 11 and 10.6 days for carprofen (2.2 mg kg^?1 every 12 hours), carprofen (4.4 mg kg^?1 every 24 hours), meloxicam and deracoxib, respectively.Conclusions and clinical relevanceOral administration of some COX-2 selective NSAIDs causes detectable alterations in platelet function in dogs. As in humans, PFA-100 collagen/ADP cartridges do not reliably detect COX-mediated platelet dysfunction in dogs. Individual assessment of platelet function is advised when administering these drugs prior to surgery, particularly in the presence of other risk factors for bleeding.     

Agricultural sources and sinks of carbon

Most existing agricultural lands have been in production for sufficiently long periods that C inputs and outputs are nearly balanced and they are neither a major source nor sink of atmospheric C. As population increases, food requirements and the need for more crop land increase accordingly. An annual conversion of previously uncultivated lands up to 1.5 × 10⁷ hectares may be expected. It is this new agricultural land which suffers the greatest losses of C during and subsequent to its conversion. The primary focus for analysis of future C fluxes in agroecosystems needs to be on current changes in land use and management as well as on direct effects of CO₂ and climate change. A valid assessment of C pools and fluxes in agroecosystems requires a global soils data base and comprehensive information on land use and management practices. A comprehensive effort to assemble and analyze this information is urgently needed.