A triple cropping system, combining spring maize, pearl millet, and twice-cut blast disease resistant Italian ryegrass, was examined for the 2016–2017 and 2017–2018 growing seasons to achieve quality herbage production in Miyazaki, southern Kyushu, Japan. The growth of the three crops reached to harvest, even though typhoon and heavy rainfall occurred. Annual dry matter (DM) yield of the triple crops was 4098 g m⁻² and 4349 g m⁻² in the first and second cropping seasons, respectively. The observed total digestible nutrients (TDN) were higher in spring maize (up to 68.2% and 76.8%), pearl millet (up to 60.0% and 67.9%), and Italian ryegrass (up to 71.6% and 68.6%), during the first and second season, respectively, leading to an annual TDN yield of 2357 g m⁻² and 2938 g m⁻². The results suggest that the present established triple cropping system is feasible for obtaining high yields with more digestible nutrients in the forages.

We investigated the root distribution and nitrogen fixation activity of American jointvetch (Aeschynomene americanaL.) cv. Glenn, under waterlogging treatment. The plants were grown in pots under three different treatments: no waterlogging (control), 30 days of waterlogging (experiment 1), and 40 days of waterlogging (experiment 2). The plants were subjected to the treatments on day 14 after germination. Root dry matter (DM) weight distribution of waterlogged plants was shallower than controls after day 20 of waterlogging. Throughout the study period, the total root DM weight in waterlogged plants was similar to that in the controls. Enhanced rooting (adventitious roots) and nodule formation at the stem base were observed in waterlogged plants after day 20 of waterlogging. The average DM weight of individual nodules on the region of the stem between the soil surface and water surface of waterlogged plants was similar to that of individual taproot nodules in the controls. Waterlogged plants had slightly greater plant DM weight than the controls after 40 days of treatment. The total nitrogenase activity (TNA) of nodules and nodule DM weight were higher in waterlogged plants than in the controls. Waterlogged American jointvetch had roots with nodules both around the soil surface and in the area between the soil surface and water surface after 20 days of waterlogging, and they maintained high nitrogenase activity and net assimilation rate that resulted in an increased growth rate.

This study assesses the impact of defoliation applied to three developmental stages across three cropping seasons from 2021 to 2023 on growth, yield and forage quality in maize. The experimental design included three treatments: defoliation of three expanded leaves at the 3rd–4th leaf stage (DF1), the 5th–6th expanded leaves by leaf punch (DF2) and expanding leaves with the DF2 treatment (DF3) at the 6th–7th leaf stages, compared with no defoliation (control). Over three years, the most significant decrease in dry matter (DM) yield occurred in DF1 during spring sowing, while in summer sowing, the largest reduction was in DF3, both of which were correlated with changes in the number of grains per ear. The DM yields at harvest were positively correlated with plant leaf areas at the silking stage. The digestibility of forage in in vitro DM decreased concomitantly with an increase in acid detergent fiber content, indicating a decrease in forage quality. Given the frequent severe damage observed in summer sown maize and the detrimental effects of early growth stage leaf feeding on quality and quantity of spring sown maize, the application of registered insecticides is advised to reduce pest damage to maize crops.

This research aimed to assess how different sowing methods and seeding rates influenced the growth, yield characteristics, and forage nutritional value for establishing American jointvetch, a tropical forage legume known for its high productivity and quality, in grasslands in southwestern Japan. The experimental treatments involved two sowing methods, row sowing (RS) and broadcast sowing (BS), and combinations of four different seeding rates (SR, 5, 10, 20, or 30 kg ha⁻¹). The sowing methods affected dry matter yield (DMY): BS resulted in higher DMY (11.3 vs. 8.7 t DM ha⁻¹) and leaf area index (LAI, 7.2 vs. 5.3) than RS, respectively. However, in vitro dry matter digestibility (IVDMD) and crude protein (CP) concentrations were not influenced by the sowing methods. The SR affected LAI, particularly RS, and LAI increased with increasing SR. Contrary to expectations, SR did not affect DMY, IVDMD, CP, digestible DMY, or CP yield. The findings of this investigation indicate that broadcast sowing is the superior method for planting, and even when using a reduced seeding rate of 5 kg ha⁻¹ of seed-in-pod, there was no significant impact on the yield or forage quality of American jointvetch under the conditions examined in this study. This information will contribute to the proper management of its cultivation to ensure higher productivity for use as livestock fodder.

SUMMARY: The present study investigated the dry matter yield (DMY) and arbuscular mycorrhizal (AM) colonization (internal hyphae, arbuscules, and vesicles) of two genotypes of zoysia grass (Zoysia japonica strain Aso and cv. Asagake) at three rates (10, 20 and 40 g N/m²/year) of application of digested slurry (DS) or mineral fertilizer. Soil chemical properties (available phosphorus concentration, pH and electrical conductivity (EC)) were also measured as factors associated with AM colonization. The fertilizer type (DS v. mineral fertilizer) had an effect on DMY depending on the plant genotypes but had little or no effect on AM colonization, and soil chemical properties, indicating that DS can be used as a substitute for mineral fertilizer; however, it is necessary to apply it taking into account the ratio of inorganic nitrogen (N). However, heavy DS application decreased colonization by internal hyphae. Furthermore, even at the lowest rate, the continuous application of DS decreased colonization by arbuscules and vesicles in both genotypes, which were associated with decreasing soil pH and increasing EC. The results suggest that zoysia grass should be fertilized with DS at a rate of <10 g N/m²/year in order to achieve a continuous association with AM fungi, although this range of N application is sub-optimal for zoysia grass production.