A fermented juice from macerated napiergrass containing epiphytic lactic bacteria (FJLB) and napiergrass was prepared, mixed with defatted rice bran (FJLB + DRB) or dried green tea waste (FJLB + DTW) and freeze-dried. Silage was treated with FJLB + DRB, FJLB + DTW, DRB or DTW in powder form at levels of 2, 10 and 50 g kg −1 fresh matter (FM). FJLB in liquid form was added at a level of 10 mL kg −1 FM. All treated silages were well preserved, with lower pH, acetic acid and NH 3 -N content and higher lactic acid content than that of the control. Butyric acid was present only in the control silage and those treated with DRB or DTW. Without powdered FJLB additives, napiergrass silages had higher pH values, butyric acid and NH 3 -N content, but low lactic acid content compared with powdered FJLB silages. Increasing the amount of all powdered additives had effect on lactic acid and NH 3 -N content. It may thus be concluded that the powder form of FJLB was as effective in improving the fermentative quality of napiergrass as the liquid form.

This experiment examined the characteristics of fermented juice of epiphytic lactic acid bacteria (FJLB) prepared by the addition of glucose, sucrose and molasses as a fermentation substrate. The effect of FJLB on the fermentative quality and changes in chemical composition during fermentation of guineagrass silage were also investigated. The pH value of the silages treated with FJLB rapidly decreased, and reached to the lowest value within 7 days of start of fermentation, as compared to the control. The number of lactic acid bacteria (LAB) in the treated silages increased for the first 3 days, thereafter the number of LAB declined gradually up to the end of the experiment. Silages treated with FJLB had larger populations of LAB than the control. Ammonia-nitrogen production increased throughout the ensiling period, which in the control and no-sugar added FJLB silages were higher than the other treated silages. Lactic acid levels varied with the time of ensiling and among the silage treatments. For any sugar FJLB treated silages, the lactic acid increased initially, and then slightly reduced to less than 50 g/kg of dry matter until 49 days after ensiling, except the silage treated with glucose added FJLB. Nevertheless, lactic acid content of the control decreased constantly from the beginning of ensiling and was not found after 35 days. Moreover, acetic acid content increased throughout the ensiling period. All the FJLB treated silages had significantly (p<0.05) lower pH and ammonia-nitrogen content, while significantly (p<0.05) higher lactic acid content and V-score value compared with the control. This study confirmed that the applying of FJLB with any sugar substrate improved fermentative quality of silage.

A greenhouse pot-experiment was conducted to evaluate the phytoremediation abilities of three tropical pasture grasses (signalgrass, napiergrass and atratum) in response to two types of soils (Kunigami-maji and Shimajiri-maji) contaminated with three levels of lead (0, 150 and 300 mg kg -1 ). The results demonstrated that the dry biomass, lead concentration and the accumulated amounts were different among the plant species and between the soil types. The amounts of dry matter in three tropical pasture grasses grown on Kunigamimaji soil were higher than that on Shimajiri-maji soil. On both soils, lead concentration of roots was higher than that of shoots, and it was suggested that transportation of lead from roots to shoots was restricted in these plants. The lead accumulated amounts per plant grown on Kunigami-maji soil were higher than that on Shimajiri-maji soil. And, on Kunigami-maji soil, accumulation of lead was relatively high in both shoots and roots of signalgrass and atratum, while, in napiergrass, the high level of lead was found only in roots. Amounts of lead extracted from the shoots of signalgrass, napiergrass and atratum grown on Kunigami-maji soil contaminated with the highest lead level of 300 mg kg -1 were 1.64, 0.17 and 0.92 mg plant -1 , respectively. As Kunigami-maji had lower soil pH than Shimajiri-maji, it can be suggested that lower soil pH may enhance lead bioavailability and uptake by the tropical pasture grasses. In conclusion, signalgrass and atratum could be useful for phytoremediation of lead contaminated soil, especially on Kunigami-maji soil.

Liming the contaminated soil is the most widely used remediation treatment to reduce the bioavailability of heavy metals. The objective of this study was to evaluate the effect of liming on the change of dry matter and lead uptake by three tropical pasture grasses from lead contaminated acidic soil. Lime at five rates of 0, 1, 2, 3 and 4 g kg−1 soil was amended to the Neubauer's pots filled with 500 g Kunigami‐maji soils and then the limed soil was contaminated with 150 mg kg−1 lead after it was maintained for 1 week. Addition of lime increased soil pH significantly from 4.43 to 5.40. The root and shoot dry matter of all three tropical pasture grasses increased with the increasing doses of lime. An elevation of soil pH induced by liming resulted in a significant reduction of lead concentrations in both roots and shoots of all experimental grasses. The effectiveness of liming on lead concentration and accumulation varied with the pH values of limed soil and grass species. The results of this study imply that napiergrass was the most effective tropical pasture grass in reducing lead concentration and accumulation of roots and shoots as a consequence of liming, and could be used for lead stabilization in moderately lead contaminated acidic soil. The shoot lead concentration of napiergrass in limed soils was within the critical level of lead tolerable to feeding domestic animals, and may act as low level lead toxicity in fodder for grazing livestock. However, lime application or soil pH had a little influence on the lead accumulated amount in roots and shoots of atratum and signalgrass. The high amounts of lead accumulated in shoots of atratum and signalgrass were found to be useful for lead phytoextraction.