Bulletin of The Iwate Agricultural Research Center No.7

Goals and Direction of Technological Development Viewed from Local Investigations of Direct-seeding Rice Cultivation in Iwate Prefecture
@Direct-seeding is anticipated to be a labor-saving and a low-cost production technology. In Iwate Prefecture, the direct-seeding method still remains in the experimental introduction stage. It appears that more technological developments are needed for direct-seeding to become more widespread. Interview surveys of managers who have incorporated direct-seeding were conducted to determine the motivation for introducing direct-seeding and the conditions for full-fledged incorporation. In addition, an examination into the issue of cost was carried out through cost comparison between transplanting and direct-seeding methods. Results from this study indicate that management organizations which introduced direct-seeding were divided into two types; those who pursue opportunity cost and those who seek marginal profit. The former anticipates the original goal of direct-seeding, that is the labor-saving aspect, while the latter encompasses many of the large-scale rice farming operators who require more perfected technology. This indicates that one of the aims for improvement of direct-seeding is the demand for marginal profits to exceed those from transplanting. From field investigations, there were no management cases where the marginal profits exceeded that of transplanting. Utilizing the cases as a base, the crop yield necessary for marginal profits to equal that from transplanting is presented in this paper. In addition, a management model for when the goal has been achieved is also presented. Further development of direct-seeding is necessary in order to reduce variable costs and maintain a constant crop yield and attain the goal for improved marginal profits.
Breeding of a New Rice Variety "Donpishari"
Kazuhiko TAMURA, Yutaka KIUCHI, Hiroko NAKANO, Akira ABE, Tsutomu SASAKI, Kengo OGIUCHI, Shinsuke NAKAJO, Yoshiaki OGI, Hiroya ODANAKA, Masahiro TAKAHASHI, Masaki TAKAHASHI, Shigeru OGATA and Yoshinori KAMIYAMA
@A new paddy rice variety "Donpishari" was developed by Iwate Agricultural Research Center in 2005. The variety was selected from the cross between "Iwanan 7" and "Fukei 179" conducted in 1996 at ex-Kennan branch of Iwate-ken Agricultural Experiment Station. "Donpishari" was intended as a middle-maturing variety with cold weather tolerance, high lodging resistance, high panicle blast field resistance and good eating quality. "Donpishari" has been tested as a local line number "Iwate 68" since 2001. It was adopted as a recommended rice variety of Iwate Prefecture in 2005. Characteristics of "Donpishari" are as follows:

(1) Belongs to the middle maturity group, maturing earlier than "Hitomebore" and slightly later than "Akitakomachi".
(2) The plants are a particle panicle number type. Its culm length is slightly shorter than both "Akitakomachi" and "Hitomebore" and panicle number is fewer than "Akitakomachi" and "Hitomebore".
(3) High tolerance to sterility caused by low temperatures at booting stage, superior to "Akitakomachi" and same as "Hitomebore".
(4) High lodging resistance, stronger than both "Akitakomachi" and "Hitomebore".
(5) High panicle blast field resistance, stronger than both "Akitakomachi" and "Hitomebore".
(6) The eating quality is as good as "Akitakomachi" and similar to "Hitomebore".
Hydroponically Raised Seedlings and Transplanting Techniques for Paddy Rice with Long-mat in Cold Regions
Tatsuro OSATO, Katsuhiro ITO, Osamu TAKAHASHI, Aya OIKAWA, Yoshinori TAKAHASHI, Kaoru MAEYAMA, Tomokazu FUJII, Atsumi ODANAKA, Masaaki TSURUTA and Junko GOTO
@The long-mat system developed by the National Agricultural Research Center as a stable and laborsaving technology for paddy rice production was systematized for cold regions. In cold areas like Iwate Prefecture, it is possible to raise seedlings in 15-17 days by warming the seedlings in the initial stages of development and then subsequently maintaining the daily water temperature 15OC and above. By adding additional fertilizer 3 days before being rolled up, nitrogen concentration of the rice seedlings increase and rooting is promoted, stabilizing early growth stages. The rolled-up seedlings can be stored for approximately 7 days. A seedling press device was attached to a conventional rice transplanter to transplant the seedlings, which resulted in fewer number of missing hills and damaged seedlings and a working capacity of 2.3-3.0 hours per hectare. Therefore by combining these technologies, the nursery device can be used twice from mid-April through sowing and temperature control, and fertilizer management, making a 4.8 hectare-scale systematized technological operation possible. Additionally, labor productivity (per time income) is increased, as the raising and transplanting of seedlings requires less effort and total labor time is cut down.
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