Maize (Zea mays L.), sorghum (Sorghum bicolor Moench) and Italian ryegrass (Lolium multiflorum Lam., IR) are major forage crops in southern Kyushu. This study tested 3 cropping systems typical to the region (double cropping of maize and IR (M-IR), double cropping of sorghum and IR (S-IR), and double cropping of maize (M-M)) for 5 years for their performance on the non-fertile, poorly permeable heavy soil. A single cropping of maize on fertile, permeable Andosol (M) was also tested for comparison. Herbage dry matter yields of summer crops (maize and sorghum) were more variable among years (CV=46.0-54.4%) than those of IR as a winter crop (CV=9.5-23.1%), with the low yields being associated with frequent attacks of typhoons and heavy rainfalls. Consequently, in M-IR and S-IR, incorporation of IR into the cropping system decreased the year-to-year variability in herbage yield (31.2 and 48.3%, respectively). Maize on Andosol (M) showed 2-34% higher yields than the 1st-crop maize on the heavy soil (M-M). The results confirm the relatively low productivity of the heavy soil and show the advantage of combining a winter crop with a summer crop for stabilizing annual herbage production on the heavy soil in southern Kyushu.

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A 5-year study was conducted to obtain information on rapid laborsaving technique to introduce Zoysia japonica Steud. into a temperate grass pasture under cattle grazing. Z. japonica seedlings (as a plug of 8cm×8cm, 5cm deep) were transplanted in early summer of the first year, being lightly firmed either onto fresh dung pats (<4 days after excretion ; new laborsaving method) or into the soil (conventional method). From the second year, the pasture was divided into 2 plots with different stocking rates (high=5-8, low=3-6 head/ha). Seedlings transplanted on dung pats were never pulled out by grazing animals and survived similarly or better than those transplanted into the soil. Development of Z. japonica plants was better at the higher stocking rate where sward height was maintained at about 10cm above ground, with the coverage of the grass reaching 54% at the end of the fifth year. The results show that transplanting seedling onto dung pats is of potential value as a laborsaving method for introducing Z. japonica into a grazed temperate pasture and maintaining sward height at about 10cm through grazing management is effective for rapid dominance of the grass.

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Effects of water management and wheel traffic on growth of rice ratoon tillers were examined in a pot experiment. Forage rice plants that had experienced light or severe wheel traffic damage by tractors at the first-crop harvesting were used in combination with treatments of 3 types of water management : flooding 1 day after harvesting the first crop, flooding 7 days after , and no flooding with watering on demand. Characteristics of the upper nodal ratoons and the basal ones were investigated. Growth of the above-ground part was not notably decreased by wheel traffic. At the late yellow ripening stage, the plant length of basal ratoons, ratoon tiller number, total dry matter weight of ratoon tillers, and root dry matter weight were significantly lower in the treatment with flooding 1 day after harvesting than in the other water managements. The total dry matter weight of ratoon tillers that corresponded to the yield at the seond harvest (aftermath) was higher in the treatment with flooding 7 days after harvesting than in the other water treatments. The basel ratoons showed greater plant length and single-tiller weight than the upper nodal ratoons, accounting for over 92% of the total ratoon tiller weight.

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An Italian ryegrass-corn-corn triple cropping, which consists of conventional-tillage (overall-tillage) cultivation of Italian ryegrass as a winter crop and minimum-tillage (partial-tillage) cultivations of corn as summer crops, is a forage production system that has a potential to maximize annual yield of quality feed with minimal labor requirements for corn establishment. Manure is applied only at the time of conventional tillage for Italian ryegrass (single application), while chemical fertilizer is applied at the tillage times for all the crops (3 applications). We tested whether an increase in the manure application level in autumn can reduce the annual use of chemical fertilizer, assuming that manure applied in autumn remains effective until the corn cropping seasons in the next year due to low mineralization and leaching of nutrients during the cool, dry winter-early spring seasons. Annual forage yield in the heavy manure plot [900kg/a manure and 2.25kg/a N, P_2O_5 and K_2O as chemical fertilizer (0.6-0.75-0.9kg/a for ryegrass-corn-corn)] was equivalent to that in the conventional manure plot [300kg/a manure and 3.7kg/a N, P_2O_5 and K_2O as chemical fertilizer (1.0-1.5-1.2kg/a for ryegrass-corn (conventional tillage)-corn)], showing the effectiveness of applying manure for the 3 crops as a single autumn application.

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Seven Dairy farms adopting grazing in eastern Hokkaido, Japan, were investigated to explore factors associated with utilization of self-supplied forage. Herbage allowances for grazing animals and production of conserved forage (mainly silage9 ranged from 25 to 42kg DM/head/day and from 2.7 to 4.0t DM/head/year, respectively, indicating that the farms produced sufficient quantities of self-supplied forage. Pasture utilization by grazing was low in most farms with short daily grazing durations (6-8 hours) and low stocking rates (&le;3 animals/ha), which presented a possibility of increasing milk production from grassland (milk derived from self-supplied forage) through improved grazing management. Milk production from grassland decreased as production of conserved forage increased, indicating less efficient use of conserved forage in more productive farms. Most farms used relatively high amounts of purchased concentrates (about 3t DM/head/year) and showed low efficiencies of concentrate use for milk production (<3.0kg milk/kg concentrate), which implied that concentrates were used in excess of supplements to self-supplied forage, i.e. concentrates contributed even to milk that could have been produced from forage. The results show that high dependence on concentrates is a major factor responsible for low utilization of self-supplied forage in dairy farms in the region.

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This study was carried out to examine the effect of proportion of green tea waste addition (10,20 and 30% on a dry matter basis) and moisture content of TMR (55, 65 and 75%) on the fermentation quality and insitu degradability of the TMR in the rumen of sheep. Lactic acid content tended to increase and the proportion of green tea waste added to the TMR increased and as the moisture content of the TMR decreased. Moisture content had small effects on the in situ degradability of dry matter, crude protein, neutral detergent fiber, and the effective degradability of TMR. Based on this study, it is recommended that the moisture content of the TMR be held at about 55%, when the TMR contains 10 to 30% green tea waste on a dry matter basis.

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We conducted a study of genetic diversity in zoysiagrass indigenous to Southwest Islands of Japan based on simple sequence repeat (SSR) markers. Forty-one lines of zoysiagrass, which included 19 Zoysia matrella, 18 Z. tenuifolia and 4 cultivars (Asagake: Z.japonica, Emeralda: Z.japonica×Z.tenuifolia, Tottori-korai: Z matrella, Velvet: Z. tenuifolia), were used in this study. From 12 SSR markers used, a total of 155 SSR bands were scored. The number of putative alleles ranged from 6 to 22, with average value of 12.9.The polymorphic information contents (PIC) of Z.matrella and Z.tenuifolia were 0.79 and 0.72, respectively. Z.matrella had significantly higher PIC than Z.tenuifolia (p=0.02). Cluster analysis based on the 155 SSR bands revealed that the 41 lines were classified into 7 groups.

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Sequence information from genomic clones containing SSR-motifs was used to design primer pairs for the amplification of SSR-based DNA markers. The markers were screened to distinguish between perennial ryegrass and Italian ryegrass. From a total of 24 primer pairs, nine fragments, amplified by six primer pairs, were identified as species-distinguishable markers. Six of these fragments were assessed for their frequencies in each of : perennial ryegrass, Italian ryegrass and hybrid rygrass. Significant differences in the frequencies of each fragment were observed between perennial ryegrass and Italian ryegrass. In hybrid ryegrass, the frequency of individuals having both perennial ryegrass and Italian ryegrass-specific DNA fragments was high. A high frequency of hybrid ryegrass individuals had both perenial ryegrass-specific nuclear DNA fragments and Itarian ryegrass-specific chloroplast DNA fragments. Cluster analysis revealed that hybrid ryegrass varieties could be separated into two clusters. We conclude that these markers would be suitable to distinguish between perennial ryegrass and Italian ryegrass, and to detect hybridization in a population of ryegrass.

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Southern corn rust is a serious disease in the warm, southwest regions of Japan. To develop closely linked molecular markers for marker-assisted selection of maize lines resistant to this disease, we studied a resistance gene of an inbred line, IM-150. In the F_2 and F_3 generations derived from a cross between IM-150 and a susceptible inbred, Mi44, the ratio of resistant to susceptible individuals based on natural infection in the field fitted the expected 3:1 segregation ratio for a dominant locus. Results of linkage analysis between the resistance gene and simple sequence repeat (SSR) markers suggest that the resistance gene of IM-150 is located on the short arm of maize chromosome 10. The results of QTL analysis based on disease ratings indicated that the resistance gene was located in a region extending more than 38cM. We combined amplified-fragment-length polymorphism and bulked segregant analysis to develop new markers closely linked to the resistance gene. Three such SSR markers will be useful in marker-assisted selection for breeding of maize resistant to southern corn rust.

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A field experiment was conducted to determine the recommended application rate of nitrogen fertilizer for mixed sown meadow of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) in Tenpoku Region in 2002-2004. The meadow was cut three times per year, and nitrogen fertilizer was applied at four levels : 0, 60, 90 and 120kgN/ha/year. The increase in DM yield per unit nitrogen applied was greatest at the 90kg application rate. However, nitrogen fertilizer reduced the proportion of legumes in the pasture, especially at the third cut in the 120kg treatment when the proportion was less than 10% in every year. At the second cut especially, higher rates of nitrogen fertilizer increased in vitro dry matter digestibility and water soluble carbohydrate contents, and decreased fiber content. We conclude that the recommended rate of nitrogen fertilizer is 90kgN/ha per year. At this rate, we estimate that the clover supplies about 40kgN/ha per year for grass growth.

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A-2-year study was conducted to evaluate productivity of Kentucky bluegrass (Poa pratensis L.)-dominant pastures continuously stocked by cattle in northern Tohoku, Japan. Grazing capacity averaged 668 cow-days ha^<-1> with a grazing period of about 190 days from late April to late October or early November. Annual herbage yield (measured only in the second year) was 10,754kg DM ha^<-1> . Chemical composition of herbage such as TDN, CP, Ca, Mg, P, K and NO_3-N concentrations and K/(Ca+Mg) ratio (measured also only in the second year) showed sufficient levels for animal growth and health. The results show that kentucky bluegrass pastures are of potential value for continuous stocking with breeding beef cows due to high vegetation persistency and productivity and sufficient herbage quality.

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Guineagrass (Panicum maximum Jacq.) was ensiled in dram to estimate the dry matter intake (DMI) by breeding Japanese Black cattle. The resultant silage was "acetic acid silage" with high pH and low lactic acid content. DMI of the silage/head was higher (P<0.05) than that of an Italian ryegrass hay, but DMI/metabolic live weight was not different significantly. It was shown that guineagrass silage was satisfactorily to use as the basal diet for breeding Japanese Black cattle.

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