A manually controlled TDR soil moisture meter operating with 300 ps rise-time needle pulse

Summary The principle of operation of a simple, manually controlled Time Domain Reflectometer (TDR meter) for soil moisture measurements, which operates with a needle pulse of 300 ps rise-time, is described. A block diagram and constructions are also given. Construction of a switchless multiple sensor probe, having an inherent delay reference, is presented. Results of measurements of the soil dielectric constant as related to water content, for soils having different bulk densities, textures and humus content show a high correlation. The results agree closely with other investigators measurements with different, more expensive, TDR instruments. The general principle of microprocessor-controlled TDR operated soil moisture meter is considered.Patent pending     

Barley yield response to irrigation and potential profits in the Texas High Plains

Summary Irrigated winter barley (Hordeum vulgare L.) can be a profitable alternative to some low profit major crops in the Texas High Plains. A six-year evaluation of yield response related to total spring irrigation water, applied by surface methods (furrow), and seasonal precipitation resulted in a multivariate function explaining 74% of the yield variation. Predicted yields varied from a low of 3.69 Mg ha^–1 to a maximum 6.18 Mg ha^–1 with 0 and 389 mm, respectively, based on average monthly precipitation quantities. Precipitation is skewed to less than average in th semi-arid Texas High Plains. Using modal precipitation amounts of 40% of average precipitation, yield estimates were reduced to 2.29 Mg ha^–1 with zero spring irrigation and to 5.63 Mg ha^–1 at the peak with 450 mm. A second multivariate yield response function related to alternative timings of single and multiple spring irrigations explained 76% of the variation in yields. Among all combinations of 1, 2, 3, and 4 spring irrigations, irrigation water-use efficiency was estimated to be highest with one application at the boot stage of development. All other single and combinations of multiple irrigations resulted in lower water-use efficiencies. A comparison of enterprise budgets of four irrigation timing alternatives and levels of application indicated highest profit over variable costs, $ 287 ha^–1, was attained by applying a total of 307 mm in three spring applications at the boot, head, and milk stages. A lower level of 217 mm applied at boot and milk stages was $ 12 ha^–1 less profitable and a higher level of 425 mm was $ 24 ha^–1 less profitable. When fixed costs of irrigation facilities, land, and machinery were considered, returns to management and risk were highest, $ 101 ha^–1, with 217 mm. Using 40% of average precipitation, profits were reduced $ 65 ha^–1 with 217 mm and $ 69 ha^–1 with 307 mm spring irrigation levels.Respectively, agricultural economist, research scientist, and research associate, Texas Agr. Exp. Station, Amarillo, Texas; Emeritus Extension agronomist, Texas Agr. Ext. Service, Amarillo, Texas; agricultural engineer, Texas Agr. Exp. Station, Amarillo, Texas     

Assessment of the impact of climate change on the latency period of leaf rust on triticale in Poland

ABSTRACT

Disease development in plants is strongly dependent on weather conditions, with temperature playing a particularly significant role by influencing latency period duration. Using two models describing the relationship between latency period and temperature, we performed simulations aimed at predicting changes in the latency period of leaf rust (Puccina recondita f. sp. tritici) on triticale in response to expected climate change. The simulations were based on meteorological data recorded in the period 1986–2005 at locations representing 16 provinces in Poland and based on values obtained after transformation of the observed data to reflect temperature changes under four scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) according to the giss_e2_r climate model. In all scenarios, the results for the two triticale cultivars studied, Witon (vulnerable to P. recondita) and Gniewko (less susceptible), showed a threat of faster development (shorter leaf rust latency period) on triticale triggered by climate change in south-east and south-central Poland than in other regions. The results also showed an increased probability of future regional diversification of leaf rust latency period duration on vulnerable triticale cultivars, opportunities for earlier start of leaf rust epidemics on triticale in Poland and an increase in ?nal disease severity in comparison with 1986–2005.     

Trace Metal Fluxes in a Sphagnum Peatland – Humic Lake System as a Consequence of Drainage

The study was conducted in a small (7.4 ha) peatland system with a humic lake concentrically surrounded by Sphagnum mat (Caricetum limosae) and Sphagnum bog (Ledo-Sphagnetum) in the Mazurian Lakeland in North-Eastern Poland. The peatland was situated in a forested catchment with a total area of 16.25 ha, and was influenced by surface drainage, artificially designed for forestry purposes. The content of zinc (Zn), cadmium (Cd), lead (Pb), copper (Cu) and hydrogen (H) ions was analysed in waters from precipitation, humic lake, mat, bog and surface outflow. The yearly budget of these ions, expressed as difference between atmospheric inflow and surface outflow, for the whole catchment was presented. The drainage of the peatland system over three years was accompanied by an increase in pH of lake, mat and bog waters. The whole catchment retention of H⁺ and trace metals studied decreased yearly in absolute values under these conditions. The peatland system began to leach Pb into surface waters and lost its ability to intercept Cd. These effects could be caused by intensity of outflow of water and sulphates and lowering of water storage. However, the potential to retain Zn and Cu ions was preserved.     

Characterization of flowering time and SSR marker analysis of spring and winter type Brassica napus L. germplasm

Flowering dates and life forms of all available Brassica napus accessions conserved at the North Central Regional Plant Introduction Station (NCRPIS) were characterized, and a survey of molecular variation was conducted by using simple sequence repeats (SSR) in order to support better management of accessions with diverse life forms. To characterize flowering phenology, 598 B. napus accessions from the NCRPIS collection were planted in Iowa and Kansas field sites together with a current commercial cultivar and observed for days to flowering (first, 50% and 100% flowering) in 2003. Days from planting to 50% flowering ranged from 34 to 83 in Iowa and from 53 to 89 in Kansas. The mean accumulated growing degree days (GDD) to 50% flowering were 1,997 in Iowa, and 2,106 in Kansas. Between locations, the correlation in flowering time (r = 0.42) and the correlation in computed GDD (r = 0.40) were both significant. Differences in flowering-time rank were observed for several accessions. Accessions that failed to flower in Iowa in a single growing season comprised 28.5% of the accessions; of the flowering accessions, 100% plant flowering was not always achieved. Accessions were grouped according to flowering time. A stratified sample of 50 accessions was selected from these groups, including 10 non-flowering and 40 flowering accessions of diverse geographic origins and phenological variation. The flowering time observed in the sampled accessions when grown in the greenhouse were found to be significantly correlated to the flowering time observed in the field locations in Iowa (r = 0.79) and Kansas (r = 0.49). Thirty SSR markers, selected across 18 Brassica linkage groups from BrassicaDB, and 3 derived from Brassica expressed sequence tags (ESTs) were scored in the stratified sample. An average of three bands per SSR primer pair was observed. Associations of SSR marker fragments with the life forms were determined. Analysis of molecular variation by using cluster analysis and ordination resulted in recognizable, distinct groups of annual and biennial life-form types, which may have direct applications for planning and management of future seed regenerations. Mention of commercial brand names in this paper does not constitute an endorsement of any product by the U.S. Department of Agriculture or cooperating agencies.     

Geochemistry of the Hyperalkaline Gorka Pit Lake (pH?>?13) in the Chrzanow Region, Southern Poland

The Gorka pit lake was formed in an inactive Jurassic limestone quarry after cessation of open-pit dewatering. The main problem of the water quality in this area is linked to a large volume of extremely alkaline leachate disposed in the flooded quarry. The lake is meromictic due to a large density contrast between shallow and deep water layers. Water in the lake is of the Na?CCO₃?COH type, pH is in the range from 11.5 to 13.3, and there are high concentrations of sulfate and several toxic elements (Al, As, Cr, Mo, P, and V). The chemical composition of the extremely alkaline leachate was formed as a result of the groundwater interaction with the industrial red mud wastes containing 5?C10 wt.% of sodium carbonate. There is a trend of increasing concentrations and pH values with depth, mainly due to the in-gassing of atmospheric CO₂ into the surface layer and due to density stratification in the water column. Similar stratification is observed in groundwater wells around the lake. High dissolved concentrations of oxyanionic contaminants such as As, Cr, and V are caused by their high mobility and desorption under extremely alkaline conditions. In spite of reducing conditions at the bottom of the lake, caused by high concentrations of dumped organic matter, sulfate behaves conservatively because sulfate reducing bacteria do not survive in this pH range.     

Growth Performance of All-Female and Mixed-Sex Common Carp Cyprinus Carpio L. Populations in the Central Europe Climatic Conditions

The results of a 4-yr study focused on comparing growth performance in all-female and mixed-sex populations of common carp are presented. All-female and mixed-sex populations of purebred Northern mirror carp (M72) and scaly crossbreds of female Ropsha (ROP) and male/neomale M72 carp (ROP × M72) were used for this experiment. Average weight and survival after each growing season and slaughtering value after the third and fourth year of the study were measured. While after 8 wk of rearing no differences between all-female and mixed-sex populations were found, the 1-yr-old all-female mirror carp population (M72) gained 29.7% more weight ( P < 0.0001) than the mixed-sex (68.5:± 15.8 g against 52.8:± 13.9 g; meant S.D.) population. After the second, third and fourth year of rearing, live weight was 9.5% ( P = 0.0062) and 6.8% ( P = 0.0229) and insignificantly 5.1 % higher, respectively, in the all-female population. There was no significant difference, even after the fourth growing season, in live weight between all-females and bisexual scaly crossbreds (2,192 g± 478.3 and 2,206 g± 484.5, respectively). The percentage of the main edible parts (processed body, filleting yield) was significantly higher in both mirror and scaly, all-female populations at 3 yr of age but not significantly different in 4-yr-old fish. No distinct differences in survival and body shape of all-female and bisexual populations were found. The potential of all-female populations for commercial production is discussed.     

Morphological and genetic variation of Melolontha spp. from pine stands with different composition and proportion of admixed tree species

European Journal of Forest Research - Increasing areas of gradation, making it difficult or impossible to perform restorations and forestations, and as causing tree crown damage, result in the need...     

Synchronous fluorescence spectroscopy of edible vegetable oils. Quantification of tocopherols

The study demonstrates the application of front face and right angle synchronous fluorescence spectroscopy for the characterization of edible oils. The method enables monitoring of tocopherols, pheophytins, and other fluorescent components in edible oils. Principal component analysis of synchronous fluorescence spectra revealed sample clustering according to the type of oil. Partial least-squares regression was utilized to develop calibration models between fluorescence spectra and total tocopherol content determined by HPLC. The regression models showed a good ability to predict tocopherol content. The best fitting results were obtained for 1% v/v diluted oils and for bulk samples using the entire spectrum, yielding the regression coefficient, r, of 0.991, and root mean square error of cross-validation of approximately 8%. The results presented confirm the capabilities of the fluorescence techniques as a tool for the analysis of edible oils.