Japanese Journal of Grassland Science

Centipedegrass was introduced by sowing and transplanting into the following 3 types of grasslands: Pleioblastus-type grassland, Zoysia-type grassland, and weed-dominated (Pennisetum alopecuroides and Digitaria abscendens) grassland. Then, we evaluated changes in the vegetation and diversity of the grasslands for 8 years. Centipedegrass was established in all the grasslands, regardless of the method (sowing or transplanting). Increase in centipedegrass coverage was influenced by the vegetation of the grassland ; that is, in Zoysia-type and weed-type grasslands, centipedegrass became the most dominant species in 3 to 5 years after introduction. However, in Pleioblastus-type grassland, the rate of increase in centipedegrass coverage was slow, and the summed dominance ratio of centipedegrass was second highest at the end of the investigation. The number of species and species diversity "H' "decreased with increase in centipedegrass coverage in all 3 types of grassland. This showed that the diversity in a grassland is reduced by the introduction of centipedegrass.

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We conducted field experiments to evaluate differences among silage corn cultivars in resistance to ear rot and accumulation of mycotoxins such as fumonisins, deoxynivalenol, nivalenol, and zearalenone under natural infection. We grew 12 to 16 cultivars at each of 6 sites located more than 100 km apart within the Tohoku region of Japan. The incidence of corn ear rot differed significantly among cultivars at all sites. However, the rank correlation between pairs of sites was significant for only 7 of the 15 combinations, most of which were for pairs in nearby sites. These results suggest that information, based on disease incidence, on the resistance of cultivars is applicable only within a narrow area. As cultivars with high incidences of ear rot tended to contain high concentrations of fumonisins, investigation of disease incidence may identify cultivars at high risk of fumonisin accumulation. In contrast, although concentrations of deoxynivalenol, nivalenol, and zearalenone also varied among the cultivars, they showed no correlation with the incidence of ear rot.

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The effectiveness of application of nitrogen, phosphorus and potassium to pastures corresponding to soil fertility was investigated on dairy farms. Previous studies showed that the optimal amounts of nitrogen, phosphorus and potassium application to a grass-legume mixed pasture were each 40 kg/ha under the conditions of about 100 kg/ha of exchangeable potassium and more than 20 mg/100 g of available phosphorus. Adequate herbage mass, intake and quality were maintained by omission of potassium application to pastures rich in potassium and by increase in potassium application to pastures with potassium deficiency. In each pasture, adjustment of potassium application in accordance with soil potassium fertility resulted in exchangeable potassium content close to 100 kg/ha after grazing. This would be an appropriate target for exchangeable potassium. Adequate productivity was maintained by decreasing phosphorus application to pastures rich in phosphorus and by increasing phosphorus application to pastures with phosphorus deficiency. Decrease in phosphorus application to pastures rich in phosphorus prevented the accumulation of available phosphorus but did not greatly reduce the amount of available phosphorus. Increase in nitrogen application up to 90-96 kg/ha to pastures without legumes improved herbage mass and intake. It is concluded that fertilizer control corresponding to soil fertility is beneficial for pastures.

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This study was conducted to determine the effect of fermentation quality of green soybean stover silage (GSS) for nutritive value and ruminal fluid condition on sheep fed only with GSS. Chopped green soybean stover was ensiled into container box silos without (N-GSS) or with 4 %w/w syrup waste (T-GSS) and these were stored for 7 months. Crashed alfalfa hay cube (ALF) was used as control. Six sheep were used for 3×3 Latin square design in a digestibility experiment. Ruminal fluid was taken on the last day of each period. Lactic acid and butyric acid content of N-GSS was 1.19 % and 0.78 % for fresh matter basis, respectively. Meanwhile, for T-GSS the content was 1.96% and 0.06% for fresh matter basis, respectively. Digestible crude protein content of T-GSS was higher than N-GSS and similarly for ALF. Total digestible nutrient of T-GSS was higher than that of GSS and ALF. Nitrogen balance was not affected among feeds. Ruminal pH of sheep fed N-GSS and T-GSS remained relatively higher than ALF. Ruminal volatile fatty acid concentration and NH3 concentration were not affected among feeds. We verified that fermentation quality of GSS could be improved using syrup waste and its nutritive value was higher in comparison to N-GSS and also similar to ALF.

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