Seeds of burcucumber were treated with accelerated aging, cold-stratification, and light quality illuminated during desiccation to enhance their germination and seedling emergence. The germination was increased by aging and cold-stratification although the latter treatment showed greater effectiveness than the former one. In the combined treatment of aging 6 days at 45~circC and cold-stratification, the germination was promoted under longer period of cold-stratification to reach nearly 100% in 3 week cold-stratification on the ninth day from sowing. In the sequentially combined treatment of aging, cold-stratification, and light quality during 24 hour desiccation at 35~circC , no-stratified seeds showed the highest rate in red light treatment but the lowest in far-red light. This implies that the phytochrome action run during the desiccation of imbibed seeds. The red light exposure during drying for the cold-stratified seeds after aging accelerated the germination even more than the dark treatment and germinated 100% on the next day of sowing. It is concluded that the sequential treatment of aging, cold-stratification, and red light illumination during desiccation can highly promote percentage and speed of burcucumber seed germination.

An extensive investigation has been made for the possible utilization of polypropylene spunbonded fabrics in rice seedling nursery. Considering the cropping systems available in southern part of Korea, sowing dates were fixed at April 5 and April 20 for single cropping and May 6 and May 26 for double cropping. Nursery period was fixed to 35 days for each sowing date. Four different thickness of polypropylene spunbonded fabrics, 40, 60, 80, 100 g/m2 , were tested in rice seedling nursery. The temperature and light intensity were not significantly different among the thickness of polypropylene spunbonded fabrics. Light intensity was significantly reduced in polypropylene spunbonded fabric (72.2 Klux) compared with polyethylene mm (85.5 Klux), however, the reduced light intensity was enough for seedling growth. The temperature in the polypropylene spunbonded fabric covering during low air temperature was higher than that in polyethylene mm tunnel. At transplanting, the rice seedlings grown in polypropylene spunbonded fabric condition was shorter (17cm) but healthier than those in polyethylene mm (23cm). The estimated possible nursery periods using the polypropylene spunbonded fabric covering may start from April 1 at Chinju (plain area in Southern Korea, 20m altitude) and April 15 at Susang (mountainous area, 430m altitude). Labour hours and cost were reduced by about 28% and 48%, respectively.

A field experiment was carried out to observe the weed control effects of vetch and to evaluate vetch characteristics on clay loam soil in no-till direct-sown rice-vetch cropping systems. The effects of weed control, forage productivity, and N content of vetch plants were investigated. With the progress of plant growth, density of Chinese milk vetch (Astragalus sinicus L.) gradually decreased, but densities of foxtail and other weeds decreased steeply due to the depression by the over-shaded vetch canopy in a no-till direct-sown rice-vetch cropping paddy field. The vetch density in tillage systems was lower than in notillage cropping systems. Lower vetch density occurred with an increase in foxtail density and other weeds. Weed control effect increased by the progress of vetch growth, which indicated that the vetch canopy over-shaded the weeds. Vetch straw was degraded rapidly submergence after with water at the time of wet sowing of rice. Early harvesting of vetch seed resulted in lower seed germination. To acquire enough seedlings without re-sowing, the harvesting of seed should be delayed at least 28 days after the flowering stage in order to ensure the vetch population is sustainable in a no-till direct-sown rice-vetch cropping system. In order to improve the survival of vetch plants, vetch seeds should germinate from the heading .stage to before the full-ripening stage of rice plants. To enhance the percent of over-wintering survival, vetch seeds should germinate no later than the end of October in southern Korea. The dry weight of vetch plants increased with the progress of vetch growth until the flowering stage but N content decreased for 30 days from before the flowering stage (2.9%) until the ripening stage (1.8%). We concluded that Chinese milk vetch could have an effect on weed control before the flowering stage, sustainability without re-sowing of seed annually, and effective green manure for rice pre-crop in no-till direct-sown rice-vetch relay cropping systems.

An experiment was carried out using pots to investigate the effects of Chinese milk vetch on the seedling establishment and growth in rice. Four irrigations with five-day intervals and three different levels of vetch straw were investigated. Significantly higher panicle numbers were obtained in vetch-treated pots. Vetch levels were non-treatment as checks, vetch with top removed, root plus shoot 7.5 ton/ha, and root plus shoot 3.0 ton/ha. The time for complete degradation of vetch straws was reduced from 10 days to 5 days as submerged time was delayed, and was affected by the amount of mulched vetch straws. As the mulched vetch amount increased, the time for a complete degradation was extended from 4 days to 12 days. Grain yield and its components were significantly affected by irrigation time and mulched vetch amount. Effectively controlled, lowered reduction damage from the degrading vetch straw, irrigation date and vetch amount were the most important factors for the improving of seedling establishment in direct-sown rice.

Uptake, assimilation and translocation of nitrogen and dry matter assimilation and translocation in ten rice cultivars were observed in no-till direct-sown rice-vetch cropping system. There was a large degree of variation in N-uptake, grain yield, nitrogen translocation efficiency and dry matter assimilation and translocation in tested rice cultivars. Forty kg N/ha base, as compound fertilizer (21-17-21% of N-P-K) three weeks after sowing and 30 kg N/ha top-dressed at panicle initiation stage as in the form of (NH4 )2 CO2 was applied. ‘Newbounet’, ‘Daesanbyeo’, and ‘Hwayeongbyeo’ showed higher translocation efficiency. The contribution of pre-heading dry matter assimilates to grain ranged from 33% to 99% of dry grain weight. Dry matter of ‘Calrose 76’ was lower than Newbounet but N content was higher in Calrose 76 than Newbonnet. By maturity, N content in vegetative parts declined considerably more than dry matter, vegetative and reproductive parts, N translocation efficiency, and N harvest index. Nitrogen translocation efficiency was greater in ‘Nonganbyeo’, Daesanbyeo, and Newbounet. Grain N concentration was positively correlated with N concentration or N content of the vegetative parts at heading in Nonganbyeo, ‘Dasanbyeo’, ‘Dongjinbyeo’, and Newbonnet. These results indicated that the greater amount of dry matter and N accumulated before heading stage, the higher translocation rates of dry matter to grain and the greater net losses at maturity.

본 시험은 ethephon, maleic hydrazide(MH) 및 gibberellic acid(GA3)의 처리 및 처리시기가 수도의 불임 및 다른 농업형질들에 미치는 효과를 구명하기 위하여 실시되었다. 인도형 품종인 삼강벼와 일본형 품종인 추청벼에 MH(6000ppm), ethephon(6000ppm) 및 GA3(10ppm)을 절간신장초기, 절간신장후기, 수잉초기, 수잉후기 및 출수기의 다섯단계에 걸쳐 처리하여 종실불임율, 주당수수, 간장, 수장 및 종실수량을 조사하였던바 그 결과를 요약하면 다음과 같다. 1. MH는 완전불임을 나타내었으나 출수지연, 잎마름, 줄기 및 이삭의 마름등과 같은 식물체에 대한 해작용이 심하였다. Ethephon은 50-60%에 가까운 불임율을 나타내었으나 식물체에 대한 해작용은 MH보다 그 정도가 낮았다. 2. GA3는 수도의 불임을 유기하지 않았고 간장을 약간 증가시켰다. 3. MH와 ethephon은 모두 수도의 간장 및 종실수량을 감소시켰으며 MH는 주당수수를 감소시켰다. 4. 화학제의 처리시기가 이를수록 더 높은 불임율이 유기되었고 그에 따른 해작용이 큰 것으로 나타났으며, 인도형 품종과 일본형 품종간에 불임율차이를 보였다.

보리종실의 샐리적 특성을 포장출아력과 비교함으로써 포장유묘출아율과 수량의 예측에 적합한 검정방법을 구명하고자 맥주보리 2품종과 쌀보리 2품종을 인위노화처리시켜 고온발아검정(warm germination test), 저온발아검정(cold germination test), Tetrazolium 유모세검정(TZ vigor test), 전기전도도검정(electroconductivity test)의 결과를 포장출아율 및 수량과 비교 검토 하였다. 고온발아검정과 저온발아검정이 포장출아율 예측에 효과적인 검정법으로 나타났으며, 이들의 관계는 맥주보리에서는 Y(포장출아율)=-2.962+0.229X1 (% warm germination) -0.001X2 (vigor, WGT) +0.354X3 (vigor, CT) -0.558X4 (% cold germination)으로 나타났다. 다중화귀방정식의 결정계수는 맥주보리의 경우 고온발아검정에서의 발아율만으로 포장출아율을 64%예측할 수 있었다. 고온발아유묘세, 저온발아유묘세, 저온발아율은 각각 4, 7, 9%씩 결정계수를 높혔다. 네가지 검정치의 누가적 예측효율은 맥주보리에서 84%, 쌀보리 54%였다. 수량에서는 포장출아율에서 보다 맥주보리, 쌀보리 공히 예측효과가 낮게 나타났다.

보리종자의 노화과정에서 일어나는 생리화학적인 활성을 비교 검토하여 종자세를 예측하기에 적합한 방법을 구명하기 위하여 새쌀보리, 부호보리 및 두산2002의 3품종을 ‘Wire-mesh tray’ 방법으로 41℃ , 상대습도 100%로 조절하여 1일에서 8일간 인위노화시켰다. 종자세의 지표로서 발아율 유아의 길이로 표시한 값과 각종 매개면수와의 관계를 비교하였다. 발아시험에 의한 방법이 보리종자의 퇴화진전을 확실히 반영해 주고 있으며, ATP 검정과 GADA 검정방법을 제외한 저온발아시험, 전기전도검정 및 테트라조리움 검정방법은 보리 종자세평가에 적합한 방법임을 알 수 있었다. 특히 저온발아시험에 의한 유아장과 데트라조리움 검정법이 가장 효과적인 방법임을 알 수 있었다.

백미의 alkali 붕괴도 청정에 필요한 최적조건을 구하기 위하여 test-tube miller를 사용하여 도정하고 25˚ , 30˚ , 35˚ 및 40℃ 의 온도에서, 1.4%에서 2.8%까지 8수준의 KOH 농도로 일정한 시간을 두고, Indica, Japonica등 10품종을 사용하여 alkali붕괴도 시험을 행하여, 본 정 검정에 영향을 미치는 백미의 도정 정도, KOH 농도 처리온도 및 처리시간을 점토하였다. 그 결과를 요약하면 다음과 같다. 1. Test-tube miller에서 90분간 도정한 시료는 alkali검정에 적당한 도정도를 나타내었다. 2. Japonica와 Indica를동시에 검정할 경우에는 1.8%의 KOH농도에서, Japonica만을 검정할 경우에는 1.4% 혹은 그 이하의 농도에서, 또 Indica만을 검정할 경우에는 2.2%의 농도에서 각각 30℃ , 18시간 동안 처리하는 것이 최적 조건으로 보였다.