제주지역에서 파종기이동(4월 25일, 5월 10일, 5월 25일, 6월 10일, 6월 25일)에 따른 양마의 생육특성, 수량성 및 사료 가치를 구명하기 위하여 1999년 4월 25일에서 6월 25일까지 15일 간격으로 시험하였다. 1. 초장은 4월 25일 파종구에서 278.6 cm 였던 것이 파종기가 지연됨에 따라 점차적으로 작아져서 6월 25일 파종에서 초장은 205.7 cm로 짧아졌다. 엽수, 고엽수, 경직경, 분지수 및 개체당 무게는 초장과 비슷한 경향이었다. 2. 생초, 건초, 단백질 및 TDN수량은 4월 25일 파종구에서 각각 98.5MT/㏊, 20.7MT/㏊, 2.9MT/㏊, 11.6MT/㏊로 가장 높았으나 만파할수록 점차적으로 감수되어 6월 25일 파종에서 생초수량은 45.9MT/㏊, 건초수량은 8.2MT/㏊, 단백질수량은 1.3MT/㏊, TDN수량은 5MT/㏊로 감수되었다. 엽과 경의 생초, 건초, 단백질 및 TDN수량도 만파할수록 감소되었다. 3. 파종기가 4월 25일에서 6월 25일로 지연됨에 따라 엽의 단백질 함량은 21.5%에서 24.4%로, 조지방 함량은 5.2%에서 6.1%로, NFE 함량은 39.9%에서 41.2%로, TDN 함량은 64.3%에서 69.7%로 증가한 반면에 조섬유 함량은 엽에서 20.8%에서 17.5%로, 조회분 함량은 7.9%에서 7.0%로 감소되는 경향이었다. 경의 조단백, 조지방, NFE, TDN함량은 만파 할수록 증가되었으나 조회분 및 조섬유 함량은 반대의 경향이었다. 이상의 결과로 보아 제주도 기상, 토양의 환경조건하에서 양마의 파종적기는 4월 25일로 판단되었다.

Snap bean is a new corp in Korea but believed to have a great deal of potentials for both domestic and overseas markets. The present study was performed to obtain the basic information about growth- and quality-related characteristics and to determinate the optimum seeding date and harvesting time for snap bean. Pod yield was significantly affected by seeding date. The highest pod yield was obtained from March 20 for determinate type and April 4 for indeterminate one, respectively, with the range of 13.0-23.7 t/ha. The pod length of indeterminate type was over 13cm, and the pod length was over 5 grams. The pod width for tested varieties was less than 1.0cm. Considering the pod growth characters such as pod length, pod width, and pod weight, the optimum harvesting time for immature pods of snap bean was supposed to be from 15 to 20 days after flowering. The daily yield of snap bean was begun to sharply increase from 15 days after the first flowering and the maximum yield was recorded at 30 days after flowering. For the accumulated yield, nearly 90% of total yield was obtained in 42 days after flowering.

In order to develop more stable seedling stand method in wet direct rice seeding culture, the effect of making the drainage ditches was studied in both methods of broadcast seeding on floody paddy surface and puddled-soil drill seeding. In a broadcast seeding on floody paddy surface, the ditching after seeding using a tractor or small ditch maker improved the seedling stand, and reduced the floating seedling and herbicide injury by accelerating the drainage. Suitable ditching time was at 2 days after seeding (DAS) for the tractor and at 3 DAS for the ditch maker. In the puddled-soil drill rice seeding culture, the ditching before seeding with a ditch maker at 3 days after draining effectively improved the seedling stand due to quick draining through well formed the seeding furrows. In the puddled-soil drill seeding, seedling stand number showed higher in both ditching plots synchronized with seeding compared with both only draining treatment at 1 DAS without ditching and the flooding plot condition for 6 DAS. And the suitable ditching depth was 6 cm, as considered the ditching status and drained status. These results suggest that the ditching in wet direct rice seeding is an resonable practice for improving the seedling stand through the accelerating drainage of field.

The technology of direct-seeding in rice cultivation is an innovation mainly induced by factors in market economy and is rapidly diffused among individual farmhouses. Because the effect of technology can be affected by many factors under various farming circumstances, the impact and stability of the direct-seeding technology compared with transplanting was analyzed under various topographical regions. Yield in direct-seeding was higher in plains, although the farm size producing higher yield was quite different depending on the topographical regions. In the direct-seeding cultivation of rice, man-labor hours was reduced by about 38 percent and the reduction rate showed little difference among topographical regions. Fertilizer was used about 11 percent more but the increase rate varied from 3 to 17 percent depending on regions with higher rates in plains. Application of agricultural chemicals was also increased about 9 percent in direct-seeding, but the increase rate was as high as 12 percent in suburbs. More fertilizer and agricultural chemicals were used in direct-seeding cultivation by farmhouses implementing both direct-seeding and transplanting than by those implementing direct-seeding only. Use of more fertilizers and agricultural chemicals in direct-seeding in all regions may indicate its technical instability. Major problems causing the technical instability of direct-seeding cultivation should be solved by comprehensive research considering various farming circumstances such as topographical features rather than just a top-down style research and extension.

헤어리베치의 추계 파종시기별 이듬해 4월 하순의 녹비량 및 녹비질소량의 변화를 살펴보기 위하여 첫째 1996년 및 1997전 파종기 9월 10일, 10월 1일 및 10월 20일에 각각 파종량 10, 20, 30 및 40kg/ha의 처리를 두어 이듬해 1997년 및 1998년의 5월 1일에 각각 수확하였고, 둘째 1999년의 8월 20일부터 9월 30일까지 10일 간격으로 5회에 걸쳐 파종하고 이듬해 4월 22일, 4월 27일, 5월 2일의 3회에 걸쳐 수확하여 조사한 결과는 다음과 같다. 1997년 및 1998년 5월 1일 수확시 헤어리베치의 질소함량은 4% 내외, 2000년 수확시는 3.5% 내외를 나타내었는데 파종이 빠를수록 수확시 질소함량이 다소 감소하였다. 헤어리베치의 파종량이 증가할수록 녹비의 수량은 증가하였으나 2년 모두 파종량 30 kg/ha와 40 kg/ha간에 차이가 없어 적정 파종량은 30 kg/ha로 생각되었다. 적정 파종량에서 녹비건물중 이 9월 10일 파종은 5.5-7 ton/ha, 10월 1일 파종은 4-4.5ton/ha, 順월 20일 파종은 1.3-2.2 ton/ha로 파종시기가 늦을수록 감소하였는데, 특히 파종기 10월 이후에서 현저히 감소하였다. 녹비의 질소량은 녹비건물중과 거의 비례하였는데 지상부에 포함된 질소량(파종량 30-40 kg/ha)은 9월 10, 10월 1일 및 10월 20일 파종이 각각 220-280, 160-180, 60-100 kg/ha로 파종기의 지연에 따라 뚜렷이 감소하였다. 2000년의 4월 하순 수확에서는 8월 20일, 8월 31일, 9월 10일과 9월 20일 및 9월 30일 파종이 각각 7-8, 6-7, 4-5 및 2-3 ton/ha의 녹비건물중을 나타내어 파종이 8월 하순이 9월에 비해 현저히 증가하였다. 녹비질소량 역시 8월 20일, 8월 31일, 9월 10일과 9월 20일 및 9월 30일 파종이 각각 240-290, 200-260, 150-220 및 70-120 kg/ha 나타내어 8월 하순 파종이 9월 파종에 비해 증가하였다.

춘파재배시 파종기에 따른 생육단계별 적산온도, 소요일수, 엽 전개 및 수량에 미치는 영향을 검토하기 위하여, 파성 I인 사천6호와 파성 IV인 새찰쌀보리를 공시하여 2월23일부터 10 및 간격으로 4시기에 파종하여 시험한 결과는 다음과 같았다. 1.사천6호를 2월 23일 파종하면 6월 16일에 성숙하여 생육일수가 111일 소요되었고, 3월 24일 파종하면 6월 21일에 성숙하여 생육일수는 87일 소요되었다. 파종이 늦어지면 생육일수가 단축되어 성숙기는 비슷하여지는데 이는 주로 파종에서 출수까지 일수가 단축되기 때문이었다. 2. 품종에 따라 적산온도는 출현까치는 111-142℃ , 출수까지는 683-756℃ , 성숙까지는 1274-1326℃ 소요되었다 추파성인 새찰쌀보리는 만파하면 파성이 완전히 소거되지 않아 성숙까지의 적산온도는 다른 시기에 비하여 많았다. 3. 2월 23일 파종한 사천6호는 엽이 하루에 0.1938개 전개되었으나 3월 24일 파종은 0.2156개 전개되어 파종이 늦을수록 엽전개는 빨라졌다 새찰쌀보리도 3월 24일 파종을 제외하고 같은 경향이었다. 4. 파종이 늦을수록 천립중이 감소하고 설립이 증가하여 수량이 감소하였는데, 사천6호의 2월 23일 파종은 수량이 10a당 299kg에 비하여 3월 24일 파종은 125kg으로 수량이 크게 감소하였다. 5. 춘파보리는 파성이 낮고 대립종인 사천6호가 좋았고, 가능한 일찍 파종하는 것이 좋고, 수원지방에서 늦어도 3월 10일 이전에 파종하여야 수량감소를 최소화할 수 있었다.

This study was conducted for 2 years at Chinju region to establish suitable seeding rate and fertilizing levels of nitrogen, phosphorous and potassium in spring-sown Jinyangbori. Heading and maturing were delayed by increasing fertilizers, especially nitrogen. Number of spikes per were secured by much seeding and increased application of nitrogen. One thousand grain weight reduced with increasing fertilization at any seeding rate. Relatively high harvest indices were observed with 12-10-4 at 10kg. 10a-l seeds planted, followed by 6-10-8 at 15 kgㆍ 10a-1 , and 6-10-4kgㆍ 10a-l at 20kg ㆍ 10a-l of N-P-K fertilizing combinations, respectively. There was no distinct differences on yield for various seeding rates in spring-sown barley. When seeding rate increased up to 15kgㆍ10a-1 , the positive effect of fertilizers was recognized as the function of balanced-application. It was possible to recommend 10kgㆍ10a-1 as seeding rate and 6-5-4(N-P-K)kgㆍ10a-1 as fertilizing combination in spring-time seeding considering low input and sustainable agriculture. There was no significant difference of protein content in grain by seeding rate. Increase of nitrogen fertilizer enhanced protein content in grain

무경운 담수표면산파재배시 잡초성벼의 발생양상과 비선택성 및 토양처리제를 이용한 잡초성벼 방제 결과는 아래와 같다. 1. 무경운에 의해 토양표면에서 월동한 잡초성벼의 생존율은 92.7%였고 재배벼는 4.3%였다. 2.토양내의 잡초성벼 발생심도는 건답에서 6.8cm, 무논에서 3.0cm, 그리고 무경운답에서 1.5cm로, 무경운답의 잡초성벼 발생은 건답과 무논에 비하여 토양 표층부위에서 주로 발생하였다. 3. 4월 하순의 우리나라 중부지역 평균기온인 13℃ 에서 잡초성벼 발아에 소요되는 일수는 14-15일이었다. 4. 무경운상태에서 포장 표면위에 떨어져 있는 잡초성벼의 발아를 유도한 후 비선택성 제초제인 paraquat 처리한 결과 92.2%의 잡초성벼를 방제할 수 있었으며, 토양처리제 중 가장 높은 출아억제를 보인 제초제는 oxadiazon으로 53.3%의 방제 효과가 있었다. 5. Paraquat과 oxadiazon의 체계처리에 의해 96.4%의 잡초성벼를 방제할 수 있었다.

영남내륙지역에서 직파재배용 벼 품종인 동안벼, 대산벼, 농호벼, 호안벼, 광안벼를 공시하여 적정 파종기를 구명하기 위해 시험한 결과를 요약하면 다음과 같다. 1 출아소요기간은 5월 30일 파종기에서 12일로 가장 짧았으며, 입모수는 5월 10일과 5월 30일에서 많았다. 2. 4월 30일과 5월 10일 파종에서 수수가 많아 10a당 쌀수량이 485-494 kg으로 다른 시기 보다 증수되었으며, 품종별로는 5월 10일 파종의 동안벼가 513 kg으로 가장 많았다. 3. 완전미비율은 5월 10일 파종이 90.4%로 가장 높았고, 5월 30일 파종은 83.1%로 가장 낮았다. 4. 품종별 완전미비율은 5월 10일 파종한 대산벼에서 92.1%로 가장 높았으며, 4월 20일과 5월 30일 파종한 광안벼에서 각각 동할미 및 청미의 비율이 높아 완전미비율은 78.8%로 낮았다. 5. 회귀식에 의한 적정파종기는 호안벼는 5월 10일, 동안벼는 5월 3일, 농호벼는 5월 8일, 광안벼는 5월 1일, 대산벼는 5월2일이었다.

소회향 재배법 확립을 위한 파종기와 파종방법 및 파종량이 생육과 수량에 미치는 영향을 시험한 결과를 요약하면 다음과 같다. 1. 3월 17일 이후에 파종한 구에서는 개화기의 지연이 관찰되었고 4월 16일 파종한 구에서는 성숙기의 지연도 관찰되었다. 2월 17일 파종구와 3 월 2일 파종구에서는 도복으로 수량 감소가 조사되었다. 2. 4월 1일 파종을 기준으로 할 때 파종일부터 출현기까지의 15일을 제외한 출현기부터 성숙기까지의 소요 일수는 115일로 나타났다. 3. 파종방법으로 보면 산파보다는 조파가 14% 의 수량 증가를 보였고, 파종량으로 보면 3 l /10a 가 1 l /10a 보다 24%의 수량 증가를 보였다. 4. 파종방법과 파종량을 비교해 보면, 조간 30cm 조파의 2 l /10a 와 3 l /10a 가 각각 22.2kg/10a와 23.2kg/10a 로서 가장 높았다.

In order to develop an appropriate cultural practice for a newly bred 2-rowed, waxy, naked barley cultivar 'Duwonchapssalbori' in the southern region, 2 varieties, 3 seeding dates, 4 seeding rates were designed with 2 replications. The heading and maturity dates of 'Duwonchapssalbori' were' earlier than 'Saessalbori by 2-5 and 4 days, respectively. Culm length of 'Duwonchapssalbori' was 60 to 66cm with lodging resistance. Grain yields of both varieties were 4.28-4.33 ton/ha in the plot of Oct. 20 seeding, 4.11-4.18 ton in the plot of Oct. 28 seeding, and 3.7-13.89 ton/ha in the Nov. 5 seeding. Grain yield with different seeding rates highly significantly fitted with secondary polynomial equations in the plots of Oct. 20 and Oct. 28 seedings (R2 =0.84-0.85), showing the greatest yield with seeding rate of 140kg per ha. However, the grain yield with various seeding rates in the plot of Nov. 5 seeding showed simple linear regression (R2 =0.71), showing the seeding rate over 160kg in the case of later seeding to be optimal. Number of spikes per m2 significantly contributed to grain yield, and fitted to simple linear regression (R2 =0.881-0.891), suggesting that plenty of early stands should be established at early seedling stage for high grain yield. Young spikes of 'Duwonchapssalbori' in the plot of Oct. 20 seeding elongated with linear increments since Feb. 10 (6.7mm), and showed rapid increment since March 7 (15.1mm). However, elongation of young spikes of 'Saessalbori' began from March 15 with slow increments. From these studies, the optimum seeding date and seeding rate in 'Duwonchapssalbori' were Oct. 20-28 and 140kg per ha for high grain yield in the southern regions.

Swordbean was recently introduced to Korea, and cultural technique for stable production, e.g. optimum seeding date and planting space, has not been established. This experiment was conducted to elucidate the changes of growth characteristics, yield components, and yield as affected by different seeding dates and planting spaces. Days to flowering was shortened by 4∼28 days as seeding was delayed. Stem diameter, number of pods per plant, number of seeds per plant, 100-seed weight, and seed yield tended to increase with delaying seeding up to 5 April and then to decrease with further delaying seeding. These results indicate that optimum seeding date of swordbean in unheated polyvinyl house would be early April. Although, the swordbean exhibited large increases in plant height, number of branches per plant, and stem diameter at the wider spacings, planting space could be decreased to the 60 cm plant-spacing and 30 cm row-spacing with no deleterious effect on yield.

단기.다수확을 목표로 하는 인삼의 직파재배는 육묘와 이식을 결합한 재배방법으로서 생산비의 절감과 생산성의 향상을 위한 재배양식이다. 직파 재배의 문제점을 구명하고 직파재배 기술체계의 수립을 위한 기초를 확립하고자 본 조사 연구를 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 직파재배 인삼포 예정지의 전작물로는 벼, 옥수수 및 호밀이 주로 재배되었고 예정지 관리시에 사용하는 유기물로로는 볏짚, 계분 및 호밀 짚이 많이 이용되고 있다. 예정지관리 후 직판시에는 토직묘포의 직판과 같은 방법으로 돌과 흙덩이만 골라 내고 이랑을 만들었으며 두둑의 흙을 체로 친 경우는 전혀 없었다. 2. 직파재배 인삼포의 파종밀도는 간당 196-210립으로 밀식된 상태였으며 발아율은 67%였다. 4년생의 생존율은 51%로서 이식재배 76%에 비해 현저히 낮았으나 간당 생존본수는 100본 이상으로 이식재배보다 많았다. 3. 이식재배에서와는 달리 직파재배 인삼포에서 많이 발생되었던 병은 회색곰팡이병, 모잘록병 및 줄기반점병을 위시한 줄기를 침해하는 병들이었다. 4, 3년생에서는 이식재배에 비해 직파재배한 인삼 엽장이 길었으나 4년생에서는 직파재배한 인삼의 엽장이 오히려 짧았으며, 경의 생육도 3년생에서는 직파재배 인삼이 좋았으나 4년생에서는 직파재배 인삼이 이식재배에 비해 저조하였다. 5. 전체적인 생육상은 이식재배 인삼과 대등하였으나 포장간의 생육차이가 큰 경향이었다. 직파재배 인삼은 비교적 뿌리가 짧았고 뿌리의 크기도 이식재배 인삼에 비해 약간 작은 경향이었으나 간당 뿌리 수확량은 이식재배에 비해 많았다.

To examine the seedling stand and growth as affected by early seeding dates of dry direct seeded rice in the Honam plain area of Korea, Dongjinbyeo was seeded at six seeding dates from early March to late April in rice fields of silty loam soil(Jeonbuk series) at the National Honam Agricultural Experiment Station (NHAES) for two years, 1996 and 1998. Seedling stand decreased slightly. with an early seeding date, but it produced more than the optimum seedling number except for the seeding of 25 March in 1996. Days to emergence was significantly longer, as seeding date was earlier, and days to emergence by early seeding was shortened only by 8 days because the mean air temperature was lower in 1996 than average, while in 1998, the reduction effect was nine to twenty five days because the mean air temperature was higher than average. In early seeding, various weeds occurred at the emergence date of rice and dominant weeds were Alopecurus aequailis, Ludwigia prostata and Rorippa islandica. NH4 + -N content in the soil at the 5th leaf stage and maximum tillering stage were lower, as the seeding date was earlier when nitrogen was split applied as basal and top dressed in 1996, while it was not significantly different among seeding dates when nitrogen was intensively applied as a top dressing in 1998. Tiller number at the maximum tillering stage and panicle number/m2 were more, as seeding date was earlier in 1996, while it was not different in 1998. Filled grain rate and 1,000 grain weight was not different among the seeding dates. Milled rice yield was significantly decreased in the seeding before the middle of March, but in the seeding after late March, it was not varied when compared with the normal seeding date in 1996, while in 1998, there was no difference among seeding dates. From the above results, in consideration of seedling stand, weed occurance, rice growth and milled rice yield, the critical optimum early seeding time in the southern plain area may lie in early April. But it was suggested that when soil moisture is proper for seeding practices, seeding amount is increased and nitrogen is applied after plumule emergence of rice, milled rice yield may not be reduced in the seeding of middle or late March, compared with the seeding in April.l.

To study the effects of an urease inhibitor, N-(n-butyl)-thiophosphoric triamide (NBPT), and a nitrification inhibitor, dicyandiamide (DCD), on nitrogen losses and nitrogen use efficiency, urea fertilizer with or without inhibitors and slowrelease fertilizer (synthetic thermoplastic resins coated urea) were applied to direct-seeded flooded rice fields in 1998. In the urea and the urea+DCD treatments, NH4 + -N concentrations reached 50 mg N L-1 after application. Urea+NBPT and urea+ NBPT+DCD treatments maintained NH4 + -N concentrations below 10 mg N L-1 in the floodwater, while the slow-release fertilizer application maintained the lowest concentration of NH4 + -N in floodwater. The ammonia losses of urea+NBPT and urea+NBPT+DCD treatments were lower than those of urea and urea+DCD treatments during the 30 days after fertilizer application. It was found that N loss due to ammonia volatilization was minimized in the treatments of NBPT with urea and the slow-release fertilizer. The volatile loss of urea+DCD treatment was not significantly different from that of urea surface application. It was found that NBPT delayed urea hydrolysis and then decreased losses due to ammonia volatilization. DCD, a nitrification inhibitor, had no significant effect on ammonia loss under flooded conditions. The slow-release fertilizer application reduced ammonia volatilization loss most effectively. As N03 [-10] -N concentrations in the soil water indicated that leaching losses of N were negligible, DCD was not effective in inhibiting nitrification in the flooded soil. The amount of N in plants was especially low in the slow-release fertilizer treatment during the early growth stage for 15 days after fertilization. The amount of N in the rice plants, however, was higher in the slow-release fertilizer treatment than in other treatments at harvest. Grain yields in the treatments of slow-release fertilizer, urea+NBPT+ DCD and urea+NBPT were significantly higher than those in the treatments of urea and urea+DCD. NBPT treatment with urea and the slow-release fertilizer application were effective in both reducing nitrogen losses and increasing grain yield by improving N use efficiency in direct-seeded flooded rice field.field.

Unstable seedling stand establishment of wet direct seeding culture of rice is one of the major elements preventing the extension of its culture area. In order to develop methods of seedling stand improvement in direct seeded rice on flooded surfaces, three field experiments were conducted on silty loam soil using a cultivar 'Donjinbyeo' for three years, mainly focusing on water management after seeding and seed soaking with plant growth regulators (PGRs). Under the condition of shallow flooding after seeding, seedling stand rate increased and floating seedling rate decreased in both early and normal season seeding compared to deep flooding. With earlier draining time after seeding, there was a tendency towards preferential growth of the seminal root, increase of seedling stand and decrease of the floating seedling rate. Therefore the highest seedling numbers per unit area and the lowest floating seedling numbers were found upon drainage at 1 day after seeding (DAS), while a contrary tendency was shown upon conventional drainage at 7 DAS. Seed soaking with PGRs such as Metalaxyl or mixing of Metalaxyl with gibberellic acid (GA3 ) significantly increased the seedling stand. In addition the effects of PGR treatment on seedling stand and the early growth of plants were greater under flooded conditions than under drained conditions after seeding, although draining of water after seeding improved the seedling establishment rate more when compared with the PGR treatment. These results suggest that draining management after seeding or maintaining of shallow flooding for a week is the most effective method to improve the seedling stand rate in wet direct seeding.

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.

In rice-barley cropping systems, efficient utilization of barley straw is essential, both to improve the soil fertility and to conserve the environment. In order to identify the effects of barley straw mulch rates in rice cultivation, a rice cultivar, 'Gancheogbyeo', was directly seeded on a no-tillage field synchronized with barley harvesting with five barley straw mulch rates, i.e., 0, 2.5, 5.0, 7.5 and 10.0 ton h a-1 and agronomic characters of rice and soil nitrogen were determined. The increasing of barley straw mulch rates. Dominant weed species, chestnut, occurred in large amounts in no mulching or lower mulch rates than in higher mulch rates. The content of N H4 ＋ -N in soil applied with high barley straw mulch rates was lower during the month after seeding, and then it was higher at heading date, compared with lower mulch rates or no mulch plot. As the barley straw rate increased, maximum tillering stage was delayed, and plant height was reduced. Although the lodging of rice plants was seldom observed in all plots, the breaking strength of the culm was significantly higher in the mulch rate of 10.0 ton h a-1 . With an increase of barley straw mulch rate, the effective tillering rate and spikelet number m-2 decreased while ripened grain ratio increased. The rice grain yield was slightly decreased with an increase of barley straw mulch rate, although significant differences were not found all barley straw mulch rates. These results suggest that there is no significant yield loss although the total barley straw production, approximately 5.0 ton h a-l in the present study, apply in the paddy for the following rice cultivation by no-tillage direct seeding.ect seeding.

The experiment was conducted to clarify irrigation requirement and percolation rate in rice paddy. The four rice cultural system of no-tin, till, transplanting, and direct seeding condition were treated in the lysimeter filled with sandy loam soil. The amounts of irrigation and soil percolation were measured daily, and irrigation requirement was estimated. The daily percolation was 19.5 l/~textrmm2 in no-till direct seeding on flooded paddy surface, 17.4 l/~textrmm2 in both of till-direct seeding on flooded surface and no-till transplanting, and 15.2 l/~textrmm2 in transplanting plot. This is equivalent to 19.5, 17.4, and 15.2 mm per day, respectively. Highest irrigation requirement was 3,770 l/~textrmm2 in no-till direct seeding plots. Others were 3,249, 2,577, and 2,321 l/~textrmm2 in till-direct seeding, no-till transplanting and transplanting plot, respectively. The estimated irrigation requirement of no-till transplanting, till-direct seeding and no-till direct seeding was increased by 11, 37, and 59% compared to till-transplanting plot. Percolation rate of no-till transplanting, till direct seeding and no-till direct seeding was increased by 12%, 40%, and 66%, respectively compared to the till-transplanting plot. The percolation rate in paddy soil was increased greatly after reproductive stage of rice.

한반도에서 비씨뿌리기에 의한 인공증우 가능성을 강우량 관측자료, 운량, 위성자료 및 상층관측자료로부터 조사하였다. 안동지역의 일 강수강도는 약 2.7mm/day, 1회 강수강도는 11 mm/day로 가장 작은 값을 보였다. 그러나 인공강우에 적합한 구름(운정온도가 -10'~-30')의 출현일은 1연에 130일로서 큰 값을 나타냈다. 이 지역에서 출현 운형은 층적운(Sc)이 가장 많았고, 다음으로 권운(Cirrus)및 고층운(Altostratus)였다.