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Tsukuba, Japan

Watanabe K.,National Agr. Res. Cent | Niino T.,National Institute Agrobio Science | Murayama T.,National Agr. Res. Cent | Nanzyo M.,Tohoku University
Japanese Journal of Crop Science | Year: 2011

The effects of pre-transplanting phosphorus application (PTPA) on the initial growth of cabbage and maize were investigated with regard to dry matter production, photosynthesis, root activities, root elongation, and nutrient absorption. PTPA did not promote the growth for a few days after transplanting, but promoted the subsequent growth in both crops. This promotive effect mainly depended on the increase in net assimilation rate (NAR), which coincided with the increase in photosynthetic rate and stomatal conductance. PTPA increased the absorption of phosphorus and potassium which were contained in the applied solution. Increase in P in leaf blades of maize also contributed to the increase in photosynthetic activity. In some case, PTPA also increased absorption of the other essential elements such as magnesium. Root activities, expressed by root respiration rate and bleeding rate from the stubble, were also improved by PTPA associated with longer root length in PTPA cabbage. These results suggested that PTPA enhanced photosynthesis and root activities, through enhanced P absorption, and it also enhanced root elongation for cabbage, which accelerated the rooting and increased water and nutrient absorption from soil. Sufficient supply of water and nutrients maintained a high photosynthetic rate, resulting in the growth promotion for a few weeks after transplanting. Source


Furuhata M.,National Agr. Res. Cent | Chosa T.,Tokyo University of Agriculture and Technology | Seki M.,National Agr. Res. Cent
Japanese Journal of Crop Science | Year: 2014

In 2010 and 2011, the characteristics of seedling establishment, dry matter production, and yield of rice direct-seeded by simultaneous seeding with fertilizer application were compared with those of rice direct-seeded in accordance with conventional practice to establish a direct seeding culture method using an air-assisted row seeder in a cold climate area. In the simultaneous seeding with fertilizer application, the rate of seedling establishment was the same as that in the conventional practice. After seedling establishment, top dry weight, stem number, Leaf area index and nitrogen absorption in the simultaneous seeding with fertilizer application were the same as or superior to those in the conventional practice. Thus, the yield was the same as or higher in the simultaneous seeding with fertilizer application than in the conventional practice. Source


Kokuryu T.,National Agr. Res. Cent | Chida H.,Miyagi Pref. Furukawa Agr. Exp. Stn | Shimada S.,National Agr. Res. Cent | Kato M.,National Agr. Res. Cent | And 2 more authors.
Japanese Journal of Crop Science | Year: 2010

We examined the effect of the use of moisture-adjusted soybean seeds on seedling emergence and establishment, and investigated the factors that inhibited their emergence during Japan's rainy season or in upland paddy fields. The decreased emergence rate was attributed to imbibition damage, soil microorganisms, and soil surface strength. The emergence rate of moisture-adjusted seeds was markedly higher than that of low-moisture seeds at high soil moisture levels or high soil surface strength. However, it was often lower in fields that had been flooded for a long period after sowing. Even under such conditions, however, a combination of moisture-adjustment and fungicide treatment of seeds improved the emergence rates. Since emergence-decreasing factors vary with the sowing season and year, and are difficult to predict that, however, the combined use of moisture-adjusted seeds and seed treatment with fungicides may be effective in raising emergence and establishment rates in the fields. Source


Nakano S.,National Agr. Res. Cent | Kumagai E.,National Agr Research Center For Tohoku Region | Shimada S.,National Agr. Res. Cent | Sameshima R.,Hokkaido University | And 3 more authors.
Japanese Journal of Crop Science | Year: 2015

This study aimed to estimate the large-scale effects of elevated air temperature on the phenological development of soybean by using the agro-meteorological grid data. A logistic model has been developed for describing the developmental rate (DVR) of three soybean cultivars, Ryuhou, Enrei and Fukuyutaka. Root mean square errors of the model estimation ranged from 1.4 to 2.2 days for emergence (VE) to flowering (R2) and 1.2 to 2.8 days for R2 to beginning of seed growth (R5). The model could estimate the effect of elevated air temperature on phenological development in a temperature gradient chamber. The response of DVR to air temperature change from VE to R2 was larger in the medium cultivar, Ryuhou, Enrei, than in the late cultivar, Fukuyutaka. The elevated air temperature simulation (+3°C) resulted in shortened duration of VE to R2 in the cool, early sowing region of eastern Japan by 5 to 7 days, whereas little effect was observed in the warm, late sowing region of Kyushu, in southern Japan. This large influence of elevated air temperature on the phenological development of soybean in eastern Japan was not only because of the use of cultivars sensitive to air temperature change but also because of the range of regional air temperatures, which largely alters the DVR during the cultivation period. © 2015 by The Crop Science Society of Japan. Source


Katayama K.,National Agr. Res. Cent | Hosono T.,National Agr. Res. Cent | Hosokawa H.,National Agr. Res. Cent | Shioya Y.,National Agr. Res. Cent | Nomura M.,National Agr. Res. Cent
Japanese Journal of Crop Science | Year: 2011

For establishing the stable production technology in early-direct sowing green soybean, the contribution of polyethylene (PE) film mulching to the growth and yield of green soybean was evaluated in an upland field converted from rice paddy in the Hokuriku district. Dry matter at harvest and yield of green soybean were higher in the plots of direct sowing with transparent or black PE film mulching compared with the plots of transplanting with black PE film mulching and direct sowing without mulching. This is probably due to higher seedling emergence, higher leaf area index from an early growth stage and larger number of pods. On the other hand, weed dry weight at harvest in the plot of direct sowing with transparent PE film mulching increased markedly compared with the plots of direct sowing or transplanting with black PE film mulching. These results suggest that direct sowing with black PE film mulching is effective to stabilize the yield and weed control in early-direct sowing of green soybean cultivation. Source

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