Cultivation of high-quality forage crop by using fallow field during winter is required for national high feed self-sufficiency and establishment of self-supply system of high-quality forage crop. Field experiments for cultivation of high-quality winter forage crop were conducted at the paddy and upland fields in Cheonan and Anseong city with treatments of single Italian ryegrass(IRG) and IRG mixed with forage barley at the paddy field and of single forage barley and forage barley mixed with IRG at the upland field in the Mid-west plain. Several cultivation conditions such as broadcasting IRG seed under standing rice, sowing time, tillage method, drainage condition, mixed sowing with forage barley were compared to know the change of growth, yield and quality of winter forage crop. In particular, over-wintering rate and dry matter yield were decreased significantly in late-sown IRG and moisture-stressed forage barley. Yield and quality of forage crops were increased by sowing after tillage, mixed sowing of IRG with barley at the paddy field with good drainage. High yield as much as dry matter 10 MT ha-1 with high feed value could be obtained by early sowing of feed barley mixed with IRG at the upland field. Cultivation conditions such as early sowing, sowing after tillage, drainage management are required for higher dry matter yield, quality and stable cultivation of winter forage crops in the mid-west plain of Korea.

To identify rice (Oryza sativa L.) cultivars suitable for Italian ryegrass (Lolium multiflorum Lam.)–rice double cropping systems, we investigated the yield and grain quality of four different midseason maturing rice cultivars (‘Daebo’, ‘Haepum’, ‘Haiami’, and ‘Samdeog’) and four midseason-to-late maturing rice cultivars (‘Hyunpoom’, ‘Saeilmi’, ‘Saenuri’, and ‘Samkwang’) in single rice cropping and Italian ryegrass–rice double cropping systems in paddy fields of Miryang, South Korea. We found that organic matter and available P2O5 content slightly decreased, whereas Na content increased, in the soil where Italian ryegrass was cultivated during winter compared to that in the soil that remained fallow during winter. The pH, electrical conductivity, organic matter, and contents of K+, Ca2+, Mg2+, and Na+ decreased, whereas the available P2O5 content slightly increased, in the soil where rice was harvested in both single and double cropping systems. However, compared to the optimum soil conditions for rice cultivation, available P2O5 and K+ content were high and Mg2+ content was low in both single and double cropping systems. At the heading stage, the culm length and leaf color slightly increased in most of the rice cultivars, whereas the panicle length and number slightly decreased, in the double cropped system. After harvesting, spikelet number and milled rice yield did not show a significant difference between single and double cropping systems. However, the ripened grain rate and weight per thousand grains increased slightly in the ‘Saeilmi’ and ‘Samkwang’ cultivars but remained either stable or slightly low in other cultivars in the double cropping system. The milled rice yield was high (> 500 kg/10a) in ‘Daebo’ and ‘Haepum’ among midseason maturing rice cultivars, and in ‘Saeilmi’ and ‘Saenuri’ among midseason-to-late maturing rice cultivars, in both single and double cropping systems. The head rice rate was high in midseason maturing rice cultivars in the double cropping systems, reaching > 70% in ‘Haepum’ and ‘Haiami’ cultivars, whereas it decreased in most midseason-to-late maturing rice cultivars (excluding ‘Samkwang’ cultivar), in double cropping systems. Particularly, it exceeded > 70% in the ‘Saenuri’ cultivar in both single and double cropping systems. The protein content in milled rice increased, whereas the amylose content either remained stable or slightly increased, in double cropping systems. The Toyo taste value decreased in all midseason-to-late maturing rice cultivars and slightly increased in the ‘Daebo’ and ‘Haiami’ cultivars among midseason maturing rice cultivars in double cropping systems. However, Toyo taste values in the ‘Haepum’, ‘Haiami’, and ‘Saenuri’ cultivars exceeding > 80% in both single and double cropping systems. Therefore, we recommend ‘Haepum’, ‘Haiami’, and ‘Saenuri’ cultivars as candidates for Italian ryegrass–rice double cropping systems due to high yield, head rice rate, and Toyo taste value.

The physicochemical properties of soil and the yield and quality of rice (Oryza sativa L. cv. Sailmi) were assessed using Italian ryegrass (Lolium multiflorum Lam. cv. Kowinearly)-rice double cropping systems in the paddy fields at Goseong and Miryang in southern Korea. The average temperatures during the ripening period were approximately 1 °C higher than the optimal temperature for rice ripening and the sunshine duration was reduced by frequent rainfall. Consequently, it was slightly below the optimal conditions required for rice ripening. In the soil at Goseong, winter Italian ryegrass cropping increased the pH, electrical conductivity, and the contents of organic matter, total nitrogen (T-N), available P2O5, K, Ca, and Mg than winter fallowing. Particularly, the contents of T-N and available P2O5increased significantly. In the soil at Miryang, Italian ryegrass slightly increased the electrical conductivity and the T-N, Mg, and Na contents. Therefore, winter Italian ryegrass cropping improved the physicochemical properties of paddy soils; however, Italian ryegrass-rice double cropping slightly reduced the culm length at both Goseong and Miryang, without markedly changing the panicle length or number compared to fallow-rice cropping. Furthermore, at Goseong, Italian ryegrass-rice double cropping slightly decreased the spikelet number and milled rice yield, and increased the ripened grain rate; however, at Miryang, contrasting results were observed. In addition, fallow-rice cropping revealed no differences in the head rice or opaque rice rates. The protein content was slightly increased in Italian ryegrass-rice double cropping, without significant changes in the amylose content or Toyo value, compared to that in fallow-rice cropping. The peak and breakdown viscosities were slightly decreased. These results indicate that winter Italian ryegrass cropping might alter rice taste but may not exhibit remarkable negative effects on rice cultivation. Therefore, Italian ryegrass-rice double cropping system is recommended for paddy fields in southern Korea. Nevertheless, to increase the rice yield and quality, fertilization standards for rice cropping that consider the changes in the T-N and organic matter contents in paddy fields caused by winter Italian ryegrass cropping need to be established.

For high-quality colored rice production, the cultivation environment is a critical factor. The major environmental factor is temperature, which includes the accumulated and average temperature during vegetative and reproductive stages. Generally, during the cultivation period, the temperature can be controlled by shifting the transplanting date. This study was carried out to determine the optimum transplanting date for high-quality red-colored rice production. Four red-colored rice varieties (Jeokjinju, Jeokjinjuchal, Hongjinju, and Gunganghongmi) were used as test materials. The transplanting dates were May 20 and June 5, 20, and 30 in 2015~2016. The most variable factor controlled by the transplanting date was the grain filling rate. The varieties transplanted on June 30 showed low yields owing to the decrease in the grain filling rate. In contrast, the polyphenol content increased with increasing delay in the transplanting date. Collectively, these two results indicate that the optimum transplanting date was June 20. The average temperature for 30 days after the heading date (30DAH) highly affected the polyphenol content. A lower temperature during the 30DAH induced higher polyphenol contents but also caused low yield. The optimum 30DAH temperature for obtaining a higher yield and polyphenol content was 22~23°C. Using the average 30DAH and accumulated temperatures, the optimum transplanting date was calculated as June 18 to 24 in Miryang region. The optimum transplanting date of Kyeungsangnamdo region was approximately mid-June to early July, and that of Kyeungsangbukdo region was approximately early to mid-June.

‘Nunkeunheugchal’ is a waxy black rice variety that has a large embryo. The quality of black rice depends on the anthocyanin content of the rice seed coat, which is mainly determined by cultivation environment. Factors that affect the anthocyanin content include nitrogen level, planting density, transplanting date and harvesting date. This study was carried out to investigate the optimum black rice cultivation conditions by examining the effects of different nitrogen levels and planting densities. An initial study was conducted to determine the optimum nitrogen level in which four levels of nitrogen were applied to the field (0, 4, 8 and 12 kg/10a). As the nitrogen contents were increased up to 8 kg/10a, there was a concomitant increase in rice yields. However, nitrogen levels greater than 8 kg/10a, the yield was maintained at the same level. Correlation analysis indicated that the optimum nitrogen level for maximum yield was 9.6 kg/10a. In addition, anthocyanin levels showed a trend similar to that of yield, with correlation analysis indicating that the optimum nitrogen level for maximum anthocyanin content is 10.6 kg/10a.On the basis of these results, a second study was conducted to determine the optimum combination of planting density and nitrogen level. The planting densities investigated were 30 × 12, 30 × 14, 30 × 16cm and nitrogen levels were 7, 9 and 12 kg/10a. A high planting density (30 × 12cm) was shown to produce higher numbers of tillers and yield. As calculated in the first study, a nitrogen level of 9 kg/10a shown to produce the highest anthocyanin content and yield. Collectively, the results of this study indicate that a planting density of 30 × 12 cm and a nitrogen level of 9 kg/10a is the optimal combination in terms of maximizing both rice yield and anthocyanin content.

Demand for the domestic hairy vetch seed production will be increased with the increasing interest of environment-friendly agriculture in Korea. This study was conducted during from 2000 fall to 2003 spring at upland field of National Institute of Crop Science in Suwon, Korea to compare wheat and triticale (TC) as stake crop of hairy vetch (HV), and to know proper seeding rates and ratios between TC and HV for the maximum HV seed production. As supporting crop of HV, TC was superior to wheat at the points of higher HV seed yield, stronger TC stalk for supporting, consistence of ripening stage of two seeds. In seeding method, row seeding was superior to broadcast seeding at the points of less lodging and higher HV seed yield. HV seed yield decreased with the increase of TC seeding rate in mixture cropping (row seeding), particularly at TC seeding rates over 5kg/10a. HV seed yield increased with the increase of HV seeding rate at the condition of TC seeding rates under 5kg/10a in spite of higher lodging of mixed crops at higher HV seeding rate due to higher HV aboveground dry matter. Maximum HV seed yield was obtained at TC seeding rate of 1~~1.5kg/10a as indicating HV seed yield 176kg/l0a (CV. Madison) at seeding rate of TC 1kg/10a + HV 2 kg/10a in 2001, and HV seed yield 96kg/10a (CV. Common) at seeding rate of TC 1.5kg/10a + HV 4.5kg/10a in 2003. Use of all-purpose combine harvester for harvesting and appliance for separation of mixed seeds using centrifugal force, which are prerequisite for HV seed production, was excellent in the simultaneous seeds production system of HV and TC.

N fertilizer required by rice could be reduced greatly in the rice-barley double cropping system than in the rice single cropping system. This study was conducted to investigate how much of the N fertilizer during the early stage of rice in the rice-barley double cropping system, could be saved compared to that in the rice single cropping system. This experiment was carried out at the paddy field of the National Crop Experiment Station in Suwon, Korea during three years from 1999 to 2001. Amounts of soil mineral nitrogen (SMN) and SPAD values of rice leaf during rice growing season in the rice-barley double cropping system were higher than those in the rice single cropping system under the same amount of N application during two years. Yield and N uptakes of rice at harvesting time were also higher in the rice-barley double cropping system than in the rice single cropping system during two years. Yield and N uptake of rice in the rice single cropping system were decreased when basal N fertilizer was omitted, but those reductions were not found by either omitting basal N fertilizer or omitting N fertilizer at tillering stage in the rice-barley double cropping system during 2000 and 2001. But yield and N uptakes of rice were decreased by 70 kg/10a and 2kgN/10a by the omission of both N application at basal and tillering stages in the rice-barley double cropping system in 2002. It was concluded that N fertilizer as much as tillering N fertilizer could be saved in the rice-barley double cropping system.

Cold acclimation of plants is a highly active process resulting from the expression of a number of physiological and metabolic adaptations to low temperature. Major metabolic changes in carbohydrates, protein, nucleic acids, amino acids, and growth regula

Winter hairy vetch (HV) can be used as green manure with conventional tillage system (CT), in which chemical N fertilizer required for cultivation of sub-sequent com could be fully saved, or as cover crop with no-tillage system (NT) in which soil could be protected from erosion, control of weed, and the reduction of N fertilizer application. This experiment was carried out to compare the enrichment of soil mineral nitrogen (SMN) at corn root zone, and the changes of com growth and N uptake according to HV amounts (winter fallow, above-ground HV removed, intact HV, and HV added from aboveground HV removed) under two tillage systems in the upland field of National Crop Experiment Station, Suwon, Korea in 1996. HV cultivation during winter decreased SMN a little at com planting. HV incorporation with CT increased SMN rapidly during early growth stage according to rapid decomposition of Hv. SMN by HV cover with NT was increased slowly and its increase was higher in the surface soil (soil layer 0-7.5cm) compared to deep soil layer 7.5-22cm. Com growth and N status at corn silking stage, com yield and N uptake at harvest were increased in proportion to aboveground HV amounts regardless of tillage system. Average hairy vetch nitrogen (HV-N) uptake efficiency by com was 10% higher with CT than with NT in which average HV-N uptake efficiency was 43 %. Corn yields were not different between two tillage systems, but corn N uptake was increased by 33 kgN/ha more with CT than with NT due to the increase of corn N concentration. The increase of SMN and com N uptake from HV cover with NT could not be disregarded though those with CT were higher than with NT

A single cross, Pungmiok is yellow dent hybrid maize (Zea mays L.) developed by the corn breeding team at the National Crop Experiment Station (NCES), RDA in 2002. This hybrid, which has a high yield of dry matter, total digestible nutrients (TDN), is mad

A single cross, Cheonganok, is a yellow semi-flint hybrid maize (Zea mays L.) developed by the corn breeding team at the National Crop Experiment Station (NCES), RDA in 2002. This hybrid, which has a high yield of dry matter, total digestible nutrients (T

Decomposition of green manure is necessary for the nutrient supply in farm soil. Hairy vetch as a green manure is superior to other winter legumes in terms of wintering ability and N accumulation. This experiment was carried out to investigate the decomposition and N release of hairy vetch and its effect on rice production as the following crop in paddy field. Decomposition of hairy vetch placed by soil depth of 0, 10 and 20cm at transplanting time was investigated by mesh bag method, which was enclosed chopped residue in mesh bags. The fate of 15 N derived from 15 N-labeled hairy vetch was investigated at harvest in three levels of N fertilization. Grain yield of the transplanted paddy rice cultured with hairy vetch as starter N were compared with that of applying urea as starter N in the field. Hairy vetch residue decomposed very rapidly both in transplanted and dry-seeded paddy field. In transplanted paddy field, hairy vetch residue lost 72-81 % and 86-90% of its weight after one and five month, respectively, as affected by incorporation depth. The C/N ratio of the decomposing vetch residue increased sharply during the early stages and after then, decreased slowly. The amounts of N and P released from the vetch were about 90% and 97% of initial content after one month, respectively. Recoveries of hairy vetch-15 N by rice plant were 30.6, 34.6 and 35.7% in 0, 6 and 12 kg urea-N 10 a-l application, respectively, indicating that N fertilization increased the recovery of hairy vetch. 15 N. Hairy vetch residue incorporated as starter maintained significant N H4 + -N concentration in soil water of plow layer until effective tillering stage. Grain yield in the plot applied with hairy vetch was not significantly different from that in the plot with urea. We concluded that hairy vetch incorporation could substitute starter N fertilization and showed possibility to reduce N amount of top-dressing.g.g.