Bulletin of The Iwate Agricultural Research Center No.1

Changing Levels in a River System of Pesticides used for Prevention of Rice Blast Disease
Kuniaki TSUKIJI, Mariko NAKAMINAMI and Miho ITOH

 From 1995 to 1997, a river system in Iwate Prefecture was periodically tested for residue levels of four kinds of pesticides used for prevention of Rice Blast Disease. The concentration of pesticides was measured using GC-MS.
 Isoprothiolane was detected from the middle of July to the last ten days of August, coinciding with application times, and the frequency of detection was higher than that of othre pesticides. Probenazole was detected in only a very few rivers in the river system duringtha peak period of application. Fthalide and Tricyclazole were detected in the first ten days and the middle of August, coinciding with aerial application times.
 Environmental standards relating to water pollution for Isoprothiolane, as well as water quality evaluation guides for Probenazole, Fthalide and Tricyclazole have been established. All of the amounts detected fell below the values indicated in the above standards and guides.
 The main sources of discharge of Probenazole and Isoprothiolane seemed to be the scattering of pesticides into irrigation waterways during submerged application, and water run off and overflow due to rainfall and insufficient water management of paddy fields.

Cow-calf Pasture Grazing of Japanese Black Cattle Using Sound Activated Dietary-conditioned Responses

 Pasture grazing of Japanese Black cattle has not become widespread due to a number of factors such as the sizeable observation workload necessary for artificial insemination and inferior growth of calves compared with those raised in sheds. To improve cow-calf grazing for Japanese Black cattle, we developed a system using sound activated dietary-conditioned responses to induce the cattle to gather at the feeding site and food supplements for calves.A practical trial of this system was then carried out at Sadatou public farm (Tono, Iwate).

 Results obtained in the experimental field were as follows:
 (1)Sounds made using car horns and brass bells were suitable for use as conditioned sounds in sound activated dietary-conditioned responses. (2)The best time for inducing the cattle to come to the feeding site for feeding or observation was between 9:00 and 10:00. (3)Figures for attendance at the feeding site were at the highest level in the first year of the experiment at 96.9%, with an average of 91.6%over a 3-year period. (4)Compared to the conventional grazing system of our laboratory, there was a reduction of 24% of the workload for observations and a reduction of 78% (at maximum) of the workload for capture and holding of cows in oestrus. (5)The average weight gain was 0.81 kg/day in conditioned calves who were creep-fed, while that of non-creep-fed calves in the conventional cow-calf pasture was 0.64 kg/day. (6)The most effective pasture for the creep-feeding site was Perennial ryegrass (Lolium perenne L.), which has high nutritional value and palatability, although some problems with grassland maintenance remained.

 Results obtained in the demonstrative trial at Sadatou farm were as follows:
 (1)Sounds used in the conditioning transmitted well in pastures on locations sloping either slightly up or down. (2)Average attendance at the feeding site was approximately 80% in the first year, and approximately 70% in the second year in which there was no learning period as cows already conditioned to sound were present. (3)Compared to the conventional grazing system at the farm, there was a reduction of 24% of the workload for observations and a reduction of more than 70% of the workload for capture and holding of cows in oestrus. (4)The average weight gain of calves in the trial grazing system was 0.74kg/day.

A Low-cost Wastewater Treatment Facility for Milking Center Wastewater Using Handy FRP Silos

  With the purpose of developing a low-cost wastewater treatment facility for milking center wastewater having enough wastewater purification capacities, we produced a wastewater treatment facility using handy FRP silos, and inspected its purification capacities for about two years. The wastewater treatment facility consisted of seven tanks, i.e. a collecting tank, an aeration tank, a settling tank, and four aerobic biological contactor tanks, and was made by a handy FRP silo (each volume was 2.6m3) each. In the facility, wastewater was treated by a combination of activated sludge process and biofirm process. To cut costs, crude styrene foam pellets, which are one of recycled marerials of plastic waste, were used as biological contactors. Under the condition that about 1m3/d of milking center wastewater (average properties: BOD 1,833mg/l, COD 570mg/l, SS 597mg/l, n-hexane extracts 233mg/l, total nitrogen 69mg/l, total phosphorus 16mg/l) flowed into the treatment facility, more than 95% of BOD, COD, SS and n-hexane extracts in the wastewater were removed, so that those concentrations in the treated water were much lower than the effluent standard value of the Water Pollution Prevention Law. Total nitrogen and phosphorus were not removed well by the treatment, although the concentrations of those substances in the treated water were lower than the effluent standard. Average removal efficiencies of total nitrogen and phosphorus were 72.5% and 44.0%, respectively. The construction cost of this treatment facility was estimated at about 910,000 or 1,2900,000 yen, respectively, in case of self-construction or maker-construction. Therefore, the treatment facility could construct at much lower than facilities on the market. The running costs were estimated at about 13,500 yen as electric bills for aeration by blowers.

Breeding of a New Rice Variety "Ginginga" Suitable for Sake Brewing
Hiroya ODANAKA, Yoshiaki OHGI, Hiromi SUGAWARA, Takashi SATOH, Masaki TAKAHASHI, Yutaka KIUCHI, Hideaki NAKAMURA, Yoshiaki TERUI, Hiroko NAKANO and Akikazu NAKANISHI

  A new rice variety "Ginginga" suitable for sake brewing was developed from a cross between "Yamagata-Sake 49" and "Akita-Sake 49" at the Kennan branch, Iwate Prefectural Agricultural Experiment Station (the current Quality Rice Breeding & Cultivation Research Section, Crops & Techniques Department, Iwate Agricultural Research Center). This variety was developed with the intent of breeding a middle-maturing variety suitable for Sake brewing, good grain quality and high lodging resistance.
 Breeding was conducted, using the "bulk method", in its early generations. After individual selection in the F4 generation, line selections, yield trials and tests of specific character were conducted. Also, tests to evaluate suitability for sake brewing were conducted by Iwate Industrial Research Institute and Iwate Prefecture Sake Brewing Association. As the results, "Iwanan-Sake 13" was selected from the F7 generation. "Iwanan-Sake 13" was released in Iwate prefecture as a recommended variety suitable for sake brewing and named "Ginginga" in 1999.

 The major characteristics of "Ginginga" are as follows.
(1) It belongs to the medium maturity group, and its date of heading and maturity are same as or slightly later than "Miyamanishiki" which is a leading variety for sake brewing in Iwate.
(2) It is panicle weight type with long culm and the panicle number is fewer than "Miyamanishiki".
(3) The lodging resistance is superior to that of "Miyamanishiki".
(4) It seems to have true resistance gene of Pi a and has moderate field resistance for leaf blast, and it is slightly susceptible for panicle blast.
(5) It has high tolerance to sterility caused by low temperature before heading, superior to that of "Miyamanishiki".
(6) The yielding ablity is almost same or slightly higher than "Miyamanishiki".
(7) The quality of grain is better than that of "Miyamanishiki".
(8) The weight of 1000 grains are heavier and amount of water absorption over 20 minutes are higher than for "Miyamanishiki". Crude protein content of 70% milled rice is less than that of "Miyamanishiki", and the suitability for sake brewing of "Ginginga" was juged to be supreior to that of "Miyamanishiki".
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