Analysis of the content of nitric oxide (II) metabolites rats of different ages

Nitrogen monoxide is a gas transmitter that is an important intermediary in many organ systems, especially in the central nervous system. Nitrogen monoxide is involved in the relaxation of smooth vascular muscles, activation of neurons and responsible for the cytotoxicity of macrophages. The study of change nitrogen oxide metabolite concentration helps to determine its effects on human and animal organs. The study was carried out on laboratory animals of different ages. We used a spectrophotometric method to determine the level of metabolites based on the reaction of nitrites to the Griss reagent. We noted that the maximum level of metabolites NO was observed in newborn animals at the age of 4 days. In addition, metabolite concentrations decreased gradually by 14-15 days of life, reaching a minimum of 30 days Key words: nitrogen monoxide, rats, age, metabolites of nitrogen monoxide, spectrophotometry.

Nitrogen fertilization of the forage crop: its effect on the yield and agronomic efficiency of Nitrogen

The goal was to evaluate the effect of nitrogen fertilization on the yield and EAN (agronomic efficiency of nitrogen) of the forage oat crop. To meet this goal, an experiment with a DBCA design was carried out, using 6 treatments: T0 (control), T1 (50-20-60), T2 (100-20-60), T3 (180-20-60), T4 (250-20-60) and T5 (350-20-60), repeated three times, in San Cristobal, Huacrachuco. The evolution of plant height, number of tillers per plant, fresh biomass, dry matter,% fiber and the agronomic efficiency of nitrogen (EAN) were determined. The data were analyzed with ANOVA and LSD test at 5% significance level. Treatments T5 and T4 reached higher values in stem length, higher yields of fresh biomass and dry matter by m2 . Fertilization did not change the number of tillers per plant and the% of fiber. However, the most optimal EAN was achieved with the dose of 100-20-60. Values higher than this dose of N could produce over fertilization without the plant using it efficiently. In conclusion, it is recommended to apply this dose (100-20-60) for having presented the best EAN, although the yields were lower with this dose, it would be the most appropriate for the efficient use of crop N. Key words: Nitrogen - San Cristobal, Huacrachuco – Forage

Pasture production gains from strategic winter nitrogen applications on a North Island sheep and beef hill country farm

Inadequate pasture growth from September to November has been a major constraint on animal production at Limestone Downs, Port Waikato. In an attempt to address this, urea was applied by air in two applications per year (late autumn + winter) at rates up to 250 kg N/ha/year for each of 3 years (2004-2007). Key words: nitrogen, slope, aspect, pasture growth, fertiliser response

Comparing in situ methods for measuring nitrogen mineralization under mock precipitation regimes

Measurement of soil nitrogen mineralization rates is frequently conducted in situ using a variety of methods, and often producing inconsistent estimates. We conducted a pot experiment to compare rates generated from three different in situ methods (buried bag, covered core, and resin core) under three mock precipitation regimes. Resin core incubations generated the most variable nitrogen mineralization values (9.33–0.09 µg g-1 28 d-1) presumably due to fluctuating soil moisture conditions inherent in the design. Key words: Nitrogen mineralization, in situ incubations, precipitation

Effect of nitrogen fertilizers on ammonia volatilization in wild blueberry production

Environmental losses of soil-applied N-fertilizers through ammonia volatilization were examined. Volatilization trials were established in the vegetative phase of wild blueberry production in Nova Scotia (NS) and Prince Edward Island (PE) in 2004 and 2005. Treatments consisted of no fertilizer (control) and N applications (35 kg N ha-1) of ammonium sulphate (AS), diammonium phosphate (DAP), urea (U) and sulphur coated urea (SCU). When compared with the control, results indicated significantly elevated volatilization rates for U (303% NS in 2004, 274% PE in 2005), SCU (273% NS in 2004, 205% PE in 2005) and DAP (178% PE in 2005). Results indicate that volatilization losses are significant, site specific and may contribute to reductions in nutrient availability. Key words: Nitrogen, wild blueberry, environmental losses, ammonia, volatilization

Fructan accumulation in wheat stems during kernel filling under varying nitrogen fertilization

The authors studied the accumulation of saccharides (glucose, fructose and sucrose) and fructans (1-ketsose, 6-kestose, oligofructosaccharides and polyfructosaccharides) in three different internodes of wheat stems receiving varying nitrogen supply at different stages of growth. Four levels of nitrogen supply, N1 (0, 0 and 100 kg ha-1), N2 (40, 0 and 0 kg ha-1), N3 (40, 120 and 0 kg ha-1) and N4 (40, 60 and 0 kg ha-1, standard fertilization in Hokkaido), were applied before sowing, at the six leaf stage and at the flag leaf stage, respectively. Glucose, fructose, sucrose, 1-kestose, 6-kestose, oligofructosaccharides and polyfructosaccharides were assessed in internodes 1 (upper part), internodes 2 (middle part) and internodes 3 (lower part) of the stems during early milky, middle milky and dough ripe stages. During the dough ripe stage, glucose content decreased in N1 and N2 stems, increased in N3 stems, and varied slightly in N4 stems. Fructose content was lower during the early milky stage and increased significantly during the middle milky and dough ripe stages. Sucrose content of N1 and N2 stems increased significantly during dough ripe stage, while these of N3 and N4 stems did not vary significantly. The levels of 1-kestose and 6-kestose in N1 stems were high compared with N2, N3 and N4 stems. However, their contents decreased during the dough ripe stage for 6-kestose. Oligosaccharides have shown similar variation by decreasing during the dough ripe stage, while polysaccharides decreased in N1 and N2 stems, but varied weakly in N3 and N4 stems. Total fructooligosaccharides (FOS) decreased during the dough ripe stage, particularly in internodes 1, while total FOS of internodes 3 remained quite stable. Comparatively, internodes 1 showed the lowest content compared with internodes 2 and 3. The results showed that fructans accumulated early, while a decreasing gradient was often observed from the bottom to the top of the stems. Results also showed that under N1 nitrogen fertilization rate, wheat plants accumulated high contents of fructans, and this fertilization rate could be applied in the Hokkaido region. Key words: Nitrogen, fertilization, stems, fructans, accumulation, Triticum aestivum

Effect of Different Doses of Nitrogen and Phosphorus on The Corm and Cormel Development of Gladiolus (Gladiolus sp.) cv. American Beauty

A study was conducted to evaluate the effect of different doses of nitrogen and phosphorus on the development of corm and cormel of gladiolus at the Horticulture Farm, IAAS, Rampur in 2002. Diameter, thickness and weight of the corms, and cormels were measured after 150 days of planting and the effect of nitrogen and phosphorous fertilizers was assessed. The nitrogen dose of 50 kg/ha produced the highest corm yield (17.71 g/plant), where as higher dose of nitrogen (100 and 150 kg/ha) fertilizer produced the lowest cormel yield. Variable doses of phosphorous did not produce any significant effect on corm diameter and corm thickness but it produced a significant effect on corm height and cormel yield per plant. Higher doses of phosphorous fertilizer (50 and 100 kg/ha) produced the highest yield as compared to the control. It appears that corm and cormel respond better to the higher doses of phosphorous fertilizer compared to the nitrogenous fertilizer. A significant interaction effect was observed on cormel weight. The phosphorous at 100 kg/ha and nitrogen at 0 kg/ha produced the highest cormel yield (25 g/plant), whereas nitrogen at 150 kg/ha and phosphorous at 0 kg/ha produced the lowest cormel yield (1.95 g/plant). The interaction effect suggests that cormel yield responds better to the higher level of phosphorous combined with lower level of nitrogen. Key words: Nitrogen, phosphorous, corm, cormel, gladiolus J. Inst. Agric. Anim. Sci. 26: 153-157 (2005)

Evaluation of coated seeds as a Rhizobium delivery system for field pea

Greenhouse and field experiments were conducted with field peas (Pisum sativum, L.) in soils of pH 4.4 to 6.8 to determine the best rate of inoculation with rhizobium and to evaluate pre-inoculated (coated) seeds as an alternative to the traditional seed inoculation method of using sticking agents. Inoculation rates higher than 105 cells seed–1 were usually required for high nodulation, nitrogen fixation and grain yields. Therefore, Canadian standards, which require that 105 nodulating rhizobia be delivered per seed for large-seed legumes like peas, may need to be increased. Counts of rhizobia on coated seeds were about 3 log units lower than those on freshly inoculated seeds, but coated seeds significantly outperformed standard seed-inoculated seeds in nodulation and crop yield in acid soils (pH 4.4 and 4.7). However, field pea yields were too low to have commercial value at these low pH levels. In soils with higher pH, standard inoculation resulted in greater nodulation and yield, but the differences were not always significant. It is concluded that the use of coated seeds provides a yield advantage for field pea grown on acid soils, but liming would probably be a better option. Use of coated seeds on other soils will depend on the trade-off between the time and money saved in inoculation in order to seed early and a possible reduction in yield due to insufficient numbers of rhizobia being applied. Key words: Nitrogen fixation, nodulation, Pisum sativum, pre-inoculated seeds

Soil nitrogen and lodgepole pine seedling responses to five years of legume cover

Legumes were tested for their ability to increase soil N content and improve growth of lodgepole pine (Pinus contorta Dougl. ex Loud.) seedlings in west-central British Columbia. A trial with alsike clover at varying densities were tested at one site, while three legume species (alsike clover, birdsfoot trefoil, and white clover) were tested on a second site. After five years of legume cover, mineralizable N mass of the forest floor were 0.5 to 4.5 times those of controls. Total N of the forest floor more than doubled in the seeding density study compared with controls, but was insignificant in the multiple species study. Despite observed increases in soil nitrogen, lodgepole pine growth was not enhanced by the legume treatments. Factors such as N immobilization, root distribution, low S levels, and competition for B may have limited the response of lodgepole pine seedlings to additions of biologically fixed-N. Key words: nitrogen-fixation, legumes, lodgepole pine, soil nitrogen

N credit of soybean to a following corn crop in central Ontario

Field studies were conducted to determine the nitrogen (N) fertilizer replacement value (NFRV) when soybean (Glycine max [L.] Merrill) preceded corn (Zea mays L.) in the rotation (S-C), compared to corn preceding corn (C-C). Large, replicated blocks of soybean and corn were established in 1993 and 1994 near Elora, Ontario. In the following year, each large block was subdivided into smaller plots. Fertilizer N was applied at six rates from 0 to 200 kg N ha−1 to the second-year corn crop. Corn grain yield responses to fertilizer N were fitted by quadratic regression. Maximum economic rate of N was calculated for each crop sequence and NFRV's were determined. Corn yields were consistently higher when grown after soybean (S-C) than after corn (C-C). Maximum corn yields were 10.4 and 12.3 Mg ha−1 in 1994 and 1995, respectively. NFRVs for S-C, compared to C-C, were 41 and 59 kg N ha−1 in the two years. As a result of these studies and numerous other experiments, recommended fertilizer N rates have been changed to 30 kg N ha−1 less for S-C than for C-C in central Ontario. Key words: Nitrogen credit, corn, soybean, fertilizer N, replacement value, crop rotation