In a grassland ecosystem, plant dead materials form one of the main compartments in a system of energy and matter flow, and the decomposition rate has a strong influence on changes in the ecosystem. In this study, the decomposition of dead materials of improved pasture plant species, such as Dactylis gromerata, Lolium perenne, etc., and Miscanthus sinensis on and/or in grasslands was recorded for several years and the decomposition coefficients were determined from those data, and the coefficients were related with meteorological factors such as air-temperature and precipitation by regression equations. These relationships established in this study can be utilised to determine the energy, and matter flows in grassland ecosystems, especially in the temperate-monsoon zone.

View full abstract

Bahiagrass (Paspalum notatum Flugge) is known to be highly tolerant to defoliation. This study tested defoliation tolerance of bahiagrass in terms of tiller density and lamina production under extremely severe cutting, to determine the limit of the tolerance and obtain some information on the management and utilization of the grass. In Experiment 1, a sward was defoliated every day to remove all laminae in spring-summer seasons. In Experiment 2, swards previously subjected to 2 nitrogen rates (-N and +N) were defoliated every day (D1), every 2 days (D2) or every 4 days (D4) to remove all laminae in summer-autumn seasons. Tiller density apparently started to decline after 4-6 weeks of the defoliation treatments, whereas lamina production started to decline immediately after the initiation of the defoliation treatments. The rates of decrease in tiller density and lamina production were almost always ranked D1≈D2> D4, with little effect of nitrogen rate (-N≈+N). It was shown that bahiagrass well tolerates extremely severe defoliation (removing all laminae every 1-2 days) for 4-6 weeks, almost maintaining initial tiller density and still showing some rates of lamina production.

View full abstract

This study developed empirical mathematical models for estimating utilization in herbage mass (U_M) and leaf (lamina) mass (U_L) from height measurements, using data from bahiagrass (Paspalum notatum Flugge) swards subjected to different cutting heights and intervals and nitrogen fertilizer rates. The models employed utilization in sward height (U_H) as a primary predictor, and incorporated pre-defoliation height of sward (H_<pre>) as an additional predictor. Validation of the models with independent data sets showed that agreement between estimated and measured utilization was good for U_M (R^2=0.848, RMSE= 0.048), but not for U_L (R^2=0.840, RMSE=0.101). The relatively poor predictive ability of the U_L model was partially attributed to the changes in the growth form (vertical distribution pattern of leaves) of plants subjected to a low defoliation height. The model for U_M is of potential value for estimating utilization in herbage mass in bahiagrass swards from height measurements, whereas the model for U_L needs further modification to improve its predictive ability.

View full abstract

This study was conducted to measure the dry matter losses during hay and silage making and to develop prediction equations to estimate dry matter losses from 38 records collected during two years. Forage was cut with a rotary mower and tedded by rake-tedder once or twice daily with the exception of rainy days. Dry matter losses in field curing were calculated from herbage mass, measured before and after mowing. The yield was measured by truck scale. The effects of stage of harvest, harvest number, period of processing, tedding times, difference between hay and silage making, dry matter harvested, temperature, rainfall, humidity and wind velocity during field curing on dry matter losses were analyzed using multiple regression analyses. The rate of dry matter losses during processing was 32.9% (18.5-48.7%) for hay and 21.7% (7.2-44.1%) for silage. Dry matter harvested (t/10a) had a significant negative correlation coefficient (r=-0.58) while tedding times had a significant positive correlation coefficient on the rate of dry matter losses during processing (r=0.41). The following was derived equation to estimate dry matter loss: DML = 23.66-30.94DMH + 2.06TED + 0.64AT (DML;dry matter loss during processing(%), DMH;dry matter harvested (t/10a), TED;tedding (times) and AT;average temperature (℃))

View full abstract

Two experiments were made to investigate the organic acid composition and microbial flora of fermented juice of epiphytic lactic acid bacteria (FJLB) prepared from timothy and orchardgrass. Changes in the composition and microorganisms with days of fermentation and dilution rates were investigated. Two experiments were made to investigate the effect of adding FJLB on the fermentation quality of silages. FJLB was used at various dilution rates and various volumes. In experiments 1 and 2, FJLB organic acids included lactic acid and acetic acid, and did not include butyric acid in both of the two grass FJLBs. The lactic acid bacteria level in both FJLBs had increased to the range of 10^8-10^10 cfu ml^<-1> by day 1-2 after incubation. In both grasses, FJLB with a low pH and a high lactic acid bacteria level was prepared even a high dilution rate. Among microorganisms adherent to the grass materials, lactic acid bacteria predomonantly grew in FJLB using sugars contained in the grass materials and glucose added to the culture as the substrate, and FJLB contained lactic acid and acetic acid as the fermentation products. In experiments 3 and 4, the untreated silages of timothy and orchardgrass were badly preserved. All the groups with treatment with FJLB regardless of the dilution rate in both timothy and orchardgrass were well preserved. Despite the addition of FJLBs of different volumes, all FJLB treated silages for both grasses were well preserved. When FJLB was added, the fermentation quality of the silages improved. The V score was high even when FJLB prepared at a high dilution rate (FJLB×10) was added and even when the additive volume of FJLB (1 ml kg^<-1> of FM) was reduced. These effects may have been due to lactic acid bacteria contained in FJLB that grew during the silage fermentation and produced a large amount of lactic acid, inhibiting butyric acid fermentation.

View full abstract

To determine the effect of herbage moisture contents on nutrient ingestion and ingestive behavior in ruminants, the experiment was conducted. The experiment was carried out with 2×2 factorial design using two groups of three rams fitted with rumen fistula and two treatments. In treatment G, sheep was fed on fresh orchardgrass (Dactylis glomerata L.) regrowing after the first harvesting, which was harvested at 30-40cm in height. In treatment H, sheep was fed on orchardgrass hay cutting about 15 mm lengths before feeding, which was harvested at heading stage. Voluntary intake of fresh matter was significally higher, but dry matter intake tended to be low (p=0.09) in treatment G than on treatment H. Both incoming and outgoing volumes of water were large in G treatment. Rumen fluid pH and NH_3 concentrations were higher in G treatment than in H treatment. Osmotic pressure of rumen fluid was higher in G treatment than in H treatment, but dilution rates were not different between the treatments. Feeding efficiency (Rt/Et ratio) was lower in G treatment than in H treatment and ingestive and ruminating behavior were intermittent in G treatment. It was supposed that ruminal moisture movement was different between under fresh grass feeding and hay feeding, and that especially the releasing process of moisture in the tissue of fresh forage was important to investigate ruminal digestibility of forage.

View full abstract

Lodging scores of clones and their progenies of timothy(Phleum pratense L.) were investigated in their first flush to learn the effective ways of improving its lodging resistance. In the progeny test, the scores were investigated three times at intervals of six to ten days, but the correlations among them were not clear. And the closest parent-off spring correlations of the resistances were obtained in the cases the parent-offspring differences of the growth stages where the investigations were made were the least. From these results it was concluded that the lodging resistances of timothy in different growth stages were controlled by different factors having high heritability in the narrow sense, and that, as long as the investigations were made in every growth stage, they could be improved remarkably even by an individual selection procedure.

View full abstract

A progeny test, where lines of timothy (Phleum pratense L.) for forage harvesting were grown on the competing condition with white clover (Trifolium repens L.), was carried out simultaneously with another test, where the same lines were grown on the competing condition with no other species, to learn how to improve its competitive ability in the growth after the first cut effectively. Results from the tests where the progenies as well as their parents were examined showed (1) that the competitive ability in the second flush had high heritability in the narrow sense, (2) that evaluating the ability in the third flush was less important than that in the second, and (3) that it was difficult to estimate the ability precisely without tests done under competing conditions. So it is concluded that, as long as the competitive ability of timothy is examined under competing conditions, it can be improved remarkably even by an individual selection procedure.

View full abstract