This study was conducted to elucidate the effect of harvest time and varietal differences on dry matter traits and feed composition of rice for whole crop silage (WCS). Total dry weight was closely related with the growth period; it increased with the delay of harvest time and was heavier in late heading varieties than in early heading varieties. The water content of plants decreased gradually after heading similarly in both early and late heading varieties. Total digestible nutrients (TDN) estimated by using near infrared rays increased from 20 days after heading to 40 days after heading, as the weight of panicles that contained a large amount of non-fibrous carbohydrate (NFC) increased. However, the real TDN did not increase since the ratio of unhulled rice that is hard to digest also increased during ripening. Among the early heading varieties that could be harvested before the harvest of food rice, “Bekogenki” was expected to be useful since it had a slightly larger total dry weight, slightly lower panicle weight ratio and slightly higher NFC of leaf and stem. Among the late heading varieties that could be harvested after harvesting of food rice, “Tachiayaka” was expected to be useful since it had a larger total dry weight, extremely lower panicle weight ratio, and higher NFC and sugar content of leaf and stem.
The effects of nitrogen topdressing time were investigated in three rice varieties for ready-made meals and restaurants, “Chihominori”, “Moeminori” and “Eminoaki”, which were bred by NARO Tohoku Agricultural Research Center (TARC). Early heading group “Massigura”, “Chihominori” and “Akitakomachi”and medium heading group “Hitomebore”, “Moeminori” and “Eminoaki”were also examined. The effects of early topdressing, late topdressing and no topdressing in the three varieties bred by TARC were not significantly different from those in the other varieties. Early topdressing increased the numbers of panicles and spikelets per area, resulting in a higher brown rice yield. Late topdressing slightly increased the number of spikelets per area and thousand grain weight, resulting in a larger brown rice yield. However, early topdressing increased milk white rice, resulting in an inferior grain appearance. Late topdressing increased the nitrogen content of brown rice, resulting in a slightly inferior eating quality. Judging from the yield, grain appearance and eating quality, usual time of nitrogen topdressing was estimated to be appropriate for the three rice varieties made by TARC. Brown rice yield of “Chihominori” was the same as that of “Akitakomachi”. That of “Moeminori” was slightly larger and that of “Eminoaki” was slightly smaller than that of “Hitomebore”. The three varieties bred by TARC have high lodging resistance and are expected to show a high yield under high nitrogen fertilization and/or direct seeding cultivation where “Akitakomachi” and “Hitomebore” become lodged.
The application of nitrogen fertilizer at the flowering stage is important to increase wheat protein concentration for improving the suitability for processing, especially for breadmaking. However, the application of nitrogen fertilizer is known to increase the cadmium (Cd) concentration in the grain because it increases Cd solubility in the soil through the acidification of the soil and the acceleration of ion exchange. This suggests that the grain Cd concentration may not be increased by the foliar application of urea. Therefore, we investigated the effects of soil- and foliar-application of urea at the flowering stage on the grain Cd concentration by pot and field experiments. Consequently, both soil- and foliar-application of urea increased the protein and Cd concentrations even when the pots were protected from rain and dropping of the urea solution. There was a positive correlation between grain protein concentration and grain Cd concentration. Urea application at the flowering stage delayed the senescence of the leaves and grain maturation, and in the pot experiment, it increased the thousand-grain weight, the grain yield, and the accumulation of Cd, K, Ca and Mg in the grain. It is speculated that nitrogen application increases the activity of plant and this leads to the increase of Cd uptake. The increase of grain protein concentration will inevitably lead to the increase of grain Cd concentration even if the foliar application of urea is adopted to increase the grain protein concentration.
To increase the demand for “Toramame”, we investigated techniques for early harvesting by a combination of early planting, covering with sheets (CS) and cutting at the base of the stem (CB) in Hokkaido Kitami district. Seeding 9 to 18 days earlier than the conventional date (June 1), hastened germination by 5 to 10 days and 30% maturation by 5 to 11 days. CS from the day of seeding day hastened sprouting and 30% maturation by 4 days. Early seeding with CS also increased the seed yield by 6 to 7%, and hastened 30% maturation. The longer the duration of CS, the earlier the maturation. However, a longer duration of CS beyond the third leaf stage caused breaking of the stem at the cotyledonary node due to vigorous growth. Therefore, CS should be finished before the first to second leaf stage. CB is usually conducted at the 50 to 60% maturation stage. The seed yield and grain size were not affected by advancing CB to the 30% maturation stage. The effective minimum temperature and the effective accumulated temperature for sprouting were 7.1ºC and 107.3ºC, respectively. The earliest seeding date to avoid frost damage in Kitami district was estimated based on the daily average temperature and the fact that sprouting is advanced by 4 days by CS. Thus, the seeding date could be advanced 13 days from the conventional date (May 31). Combination of these techniques makes it possible to advance the date of CB by 18 to 19 days compared with the conventional date (Sept. 19), and after drying for one month, the products can be shipped at the beginning or middle of October, as demanded by the traders.
Rice cultivars with short panicles, “Tachiayaka” and “Tachisuzuka”, were developed for silage use because of their improved feed value due to a radical decrease in hard to digest spikelets. However, these cultivars produce an insufficient number of seeds for propagation. Nitrogen application at the panicle formation stage or late transplanting improves unhulled rice yield in “Tachisuzuka”. However, this has not been confirmed in “Tachiayaka”. Therefore, the effects of the amount of total and top-dressed nitrogen fertilizer, on the yield components of “Tachiayaka” were studied in 2014 and 2015. The method of fertilization did not affect the panicle number and the ratio of selection by specific gravity. However, spikelet numbers per panicle and per unit area were increased by increasing the amount of top-dressed nitrogen fertilizer compared with that of basal dressing. Therefore, the spikelet number should be increased by reducing the basal dressing and increasing the top dressing to improve the seed production in “Tachiayaka”. However, late-emerging panicles were observed in top dressing more than 10 g m–2 nitrogen.
The effect of methane fermentation liquid obtained from livestock waste slurry (MFL) on the activity of root-knot nematodes (Meloidogyne spp.) was evaluated. On the day after preparation, MFL contained 1.86 g L–1 of ammonium nitrogen which is reported to have nematocidal activity. However, the ammonium nitrogen content decreased with the lapse of storage time. More than 90% of the population of M.incognia was immobilized by adding the five-times-diluted MLF solution to a suspension of M.incognita. This immobilization effect was also observed in other Meloidogyne spp.: M. arenaria Honshu-type, M. arenaria Okinawa-type, M.hapla, M.javanica and M.microcephalus. The population of M.incognita in soil was significantly reduced by addition of 120 mL kg–1 (equivalent to 60% of maximum water-holding capacity) MLF to soil in Sand-dune Regosol infested with M.incognita. However, this effect was not observed clearly in Gray Lowland soil and Andosol. The amount of egg masses produced by M.incognita was reduced to less than 25% of that in the control by applying 70 mL kg–1 MLF (containing 200 mg NH4+-N) to the soil of nematode-infected Sand-dune Regosol in the pot experiment with tomato seedling.
An indica-dominant high-yielding rice cultivar Hokuriku193 having a semi-dwarf gene often shows reduced seedling length and light seedling weight under low temperature conditions. Thus, we analyzed the improvements in the seedling length and weight by several nursery management methods combined with N top-dressing. Mulch heating treatment, covering seedlings above 40 cm with transparent plastic and leaving 3–4 cm of the bottom side of the plastic sheets open, increased seedling length by 3.5 cm, and maintained the seedling weight the same as or greater than the seedlings grown by the usual nursery method. The seedlings after N top-dressing showed greater seedling length, and heavier weight, and higher N content. Water depth of 5 cm during the nursery period increased seedling length by 2.9 cm, compared with the usual depth of 2 cm. Water depth of 5 cm did not significantly decrease seedling weight. The on-farm trial in cool highlands suggested that the increased length and N content of the seedlings improved the early biomass production after machine-transplanting and also decreased vacant hills.
In this paper, the optimal harvest time under the two harvests per year system for forage sugarcane variety, “Shimanoushie”, was examined in the Amami region of Kagoshima prefecture. The growth stability and yield productivity using the two harvests per year system were examined in the plots harvested in April and July (AJ), May and August (MA) or June and September (JS). The two-year average value of the annual dry matter yield was 4.05, 4.12, 3.45 kg m–2 in the AJ, MA and JS plots, respectively. The yield was significantly lower in the JS plot than in either the AJ or MA plot. Heavy lodging and damage to crops by field mice were seen in the crop harvested in April in the AJ plot. The dry matter ratio of the crop harvested in June in the JS plot was very low and not suitable for silage. The vegetative cover rate by the ratoon crop in early growth stage was significantly correlated with the mean temperature, and it was high in the post-crops of June harvest in the JS plot and of July harvest in the AJ plot. On the other hand, the rate was low in the post-crops of September harvest in the JS plot during the temperature was low, and the growth competition with weeds was concern. It is concluded that harvesting in May and August is optimal in the two harvests per year system in the Amami region.
Common buckwheat is easy to shatter and yield loss often occurs. Therefore, we examined whether the use of a ‘shattering-resistant line’ is effective for reducing yield loss. Experiments were performed at the research field of Hokkaido Agricultural Research Center in Memuro town from 2012 to 2014, and in a buckwheat field in Hokuryu town in Hokkaido from 2013 to 2015. In the standard harvest at a suitable time with a combine harvester, the ‘threshing and sorting loss’ in the ‘shattering resistant line’ was greater than in “Kitawasesoba”, showing that the yield loss was greater in the former than in the latter. On the other hand, in a later harvest with the combine harvester, ‘head loss’ was greater but yield loss was smaller in the ‘shattering- resistant line’, than in “Kitawasesoba” because the ‘threshing and sorting loss’ was decreased in the ‘shattering-resistant line’ and the ‘pre-harvest shatter loss’ was extremely greater in “Kitawasesoba”. Furthermore, it was indicated that the use of the ‘shattering-resistant line’ was effective for reducing yield loss under the conditions where shattering occurs heavily, such as in rain, strong wind, and late and extremely late harvesting.
The effects of non-tillage direct sowing culture on the growth, yield, quality and palatability of rice cultivar “Hinohikari” were investigated in 2013 and 2015. As compared with the transplanting culture condition (transplanted plots), the grain yield was reduced by 6% and 37%, respectively, under the non-tillage direct sowing condition (direct sown plots) in 2015 and 2013. In 2013, the number of ears was reduced by the suppression of seedling establishment which was affected by the shortage of rainfall before and after the seeding. No significant difference was observed between the direct sown and transplanted plots in appearance quality. Concerning the palatability, the peak viscosity and breakdown were greater, the taste was better, the stickiness was milder, and the overall palatability was higher in the direct sown plots than in the transplanted plots.