‘Gwangyoung’, a winter forage triticale cultivar (X Triticosecale Wittmack), was developed at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2018. The cultivar ‘Gwangyoung’ has leaves of wide width, medium length, and green color, and spikes of medium length and yellowish-brown color, and a large grain of yellowish-brown color. The heading date of the cultivar ‘Gwangyoung’ was April 22 which was similar to check cultivar ‘Shinyoung’. Its tolerance or resistance to cold, lodging, wet injury powdery mildew, and leaf rust were also similar to those of the check cultivar. The leaf blade ratio of ‘Gwangyoung’ (27.5%) was higher than that of ‘Shinyoung’ (21.2%). The average forage fresh and dry matter yield of cultivar ‘Gwangyoung’ at milk-ripe stages were 50.0 and 17.6 MT ha-1, respectively, which were higher than those (47.7 and 17.1 MT ha-1) of the check cultivar. The silage quality of ‘Gwangyoung’ was lower than that of the check cultivar ‘Shinyoung’ in crude protein content (5.3%) and total digestible nutrients (61.3%), while was higher than the check cultivar in neutral detergent fiber (58.2%) and acid detergent fiber (34.9%). ‘Gwangyoung’ showed the silage of 1 grade and a grain yield of 6.03 MT ha-1.

In the winter forage study, Italian ryegrass(IRG) and barley were selected. In 2018, the dry matter yield of IRG was 16,915kg per ha under the Agrivoltaic System; this was a little more than 16,750kg per ha of outdoors. On the contrary, the dry matter yield of barley was slightly less under the Agrivoltaic System than that of outdoors. In 2019, the dry matter yield under the Agrivoltaic System was 12,062kg per ha for IRG and 12,195kg per ha for the barley; this was 5.4% and 11.5% less than that of outdoors, respectively. In the summer forage study, corn and sorghum×sudangrass were selected. In 2019, the dry matter yield of corn under the Agrivoltaic System was 13,133kg per ha which was 17% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 12,450kg per ha, which was 82.5% of that of outdoors. In 2020, the dry matter yield of corn under the Agrivoltaic System was 8,033kg per ha which was 7.9% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 5,651kg per ha, which was 11.4% less than that of outdoors.

Pig slurry (PS) is the most applicable recycling option as an alternative organic fertilizer. The application of pig slurry has the risk of air pollution via atmospheric ammonia (NH3) and nitrous oxide (N2O) emission. The zeolite has a porous structure that can accommodate a wide variety of cations, thus utilizing for the potential additive of deodorization and gas adsorption. This study aimed to investigate the possible roles of zeolite in mitigating NH3 and N2O emission from the pig slurry applied to the maize cropping. The experiment was composed of three treatments: 1) non-N fertilized control, 2) pig slurry (PS) and 3) pig slurry mixed with natural zeolite (PZ). Both of NH3 and N2O emission from applied pig slurry highly increased by more than 3-fold compared to non-N fertilized control. The NH3 emission from the pig slurry was dominant during early 14 days after application and 20.1% of reduction by zeolite application was estimated in this period. Total NH3 emission through whole period of measurement was 0.31, 1.33, and 1.14 kg ha-1. Nitrous oxide emission in the plot applied with pig slurry was also reduced by zeolite treatment by 16.3%. Significant increases in forage and ear yield, as well as nutrient values were obtained by pig slurry application, while no significant effects of zeolite were observed. These results indicate that the application of zeolite and pig slurry efficiently reduces the emission of ammonia and nitrous oxide without negative effects on maize crop production.

To investigate the suitable growing area for Italian ryegrass (cv. Kowinearly and cv. Green-Call), we survey the different effects of climatic conditions on plant growth in the east (hereafter termed Yeongdong) and west (hereafter termed Yeongseo) of the passes in Gangwon Province. The Italian ryegrass was grown in Gangneung of Yeongdong and Wonju and Chuncheon of Yeongseo. The plants showed growth differences depending on the cultivated regions between before and after wintering. The Italian ryegrass for pre-wintering showed the relatively long length of plant height in Wonju. While, we observed the relatively tall plants for growing- and harvestingperiod after wintering in Gangneung. The increased plant height in Gangneung was closely related to all climatic conditions for the growing period and mean- and lowest-temperature for the harvesting period, respectively. The amount of dry matter was 7,490 kg/ha for Kowinearly and 6,490 kg/ha for Green-Call in Gangneung, which has a higher yield than Chuncheon and Wonju. The relative yield index of dry matter was 77% (Kowinearly) and 78% (Green-Call) in Chuncheon and 84% (Kowinearly) and 71% (Green-Call) in Wonju compared to Gangneung as the standard region. Thus, we suggest that Chuncheon and Wonju are the possible areas for cultivation of Italian ryegrass, considering that Gangneung was the optimum growing area in Gangwon Province.

A winter forage tetraploid rye (Secale cereale L.) cultivar, ‘Daegokgreen’, was developed at the Department of Central Area Crop Science, NICS, RDA in 2016. The mutant line ‘CG11003-8-B’, which was induced from rye cultivar ‘Gogu’ (diploid) by colchicine treatment, was selected for its excellent agronomic performance and was placed in preliminary yield trials for one year, 2013. The line was designated “Homil59” and was tested for regional yield trials at the four locations in Korea from 2014 to 2016. Finally, the new cultivar was named as the ‘Daegokgreen’ (grant number 8274). The leaf of cultivar ‘Daegokgreen’ is wide, long and dark-green color. The cultivar also has a big-size grain with light-brown color. The heading date of cultivar ‘Daegokgreen’ was April 17 which was 2 days later than that of check cultivar ‘Gogu’. The tolerance to cold and wet injury, and resistance to powdery mildew and leaf rust of the new cultivar were similar to those of the check cultivar but the resistance to the lodging of the new cultivar was stronger than that of the check. The average roughage fresh and dry matter yield of the new cultivar after 10 days from heading were 37.0 and 7.7 MT ha-1, respectively, which were similar to those (38.4 and 8.0 MT ha-1) of the check cultivar. The roughage quality of ‘Daegokgreen’ was higher in crude protein content (8.9%) than that of the check cultivar (7.9%), while was similar to the check in total digestible nutrients (56.9%). This cultivar is recommended for fall sowing forage crops at all of crop cultivation areas in Korea.

This study was conducted at the National Institute of Animal Science from 2010 to 2017. As a variety that is sufficiently productive in the southern regions to replace imported varieties and sufficiently cold-resistant to be cultivated in the central-northern regions, "IR605" was developed and submitted to the Korea Seed & Variety Service in an application for protection. The novel Italian ryegrass variety "IR605" is a diploid with green leaves, a semi-erect growth habit before wintering, and an erect growth habit in the spring. "IR605" was a medium maturing variety with a heading date of around May 15th. "IR605" had a flag leaf width of 9.9 mm, flag leaf length of 26.7 cm, and plant length on the heading date of 100 cm, which was approximately 5 cm longer than "Kowinearly." The stem thickness and ear length of "IR605" are 0.08 mm thicker and 0.5 cm longer than those of "Kowinearly", respectively. The cold-resistance of "IR605" was weaker than that of "Kowinearly", but strong enough to be cultivated in Pyeongchang, Gangwon province. The dry matter yield of "IR605" (9,308 kg/hectare) was 20% higher than that of "Kowinearly", which was further pronounced in the southern region of Haenam, where there was a 52% increased (p < 0.05). The in vitro dry matter digestibility of "IR605" was 68.4% at which was slightly higher than that of "Kowinearly", The total digestible nutrients was 58.5%, which was slightly lower than "Kowinearly". Overall, the feed quality characteristics of "IR605" were similar to those of "Kowinearly".

Cattle feeding in South Korea has been heavily dependent on domestically produced rice straw and imported grain. Around 42% of domestically produced rice straw is utilized for forage, and the remainder is recycled to restore soil fertility. Approximately 35% of round baleages were made with rice straw. However, higher quality hay is desired over rice straw. Due to increasing stockpiles of rice, there has been an economic burden on the government to store the surplus; therefore production of annual forage crops in rice fields has been further promoted in recent years. Hay import from the USA currently constitutes more than 80% of total imported hays. The main imported hays are alfalfa (Medicago sativa), timothy (Phleum pretense), and tall fescue (Festica arundinacea). The estimated forage required for cattle feeding was approximately 5.4 million MT in 2016. Domestically produced forage sates only 43% of that value, while low quality rice straw and imported hay covered the rest of demand by 33% and 20%, respectively. As utilization of domestically produced forage is more desirable for forage-based cattle production, long-term strategies have been necessary to promote domestic production of high quality baleage. One such strategy has been utilizing the fertile soil and abundance of fallow rice fields of western region of S. Korea to produce forage crops. Italian ryegrass (Lolium multiflorum) is the most successfully produced winter annual in the region and is approximately 56% of the total winter annual forage production. Forage sorghums (Sorghum bicolor), sorghum × sudangrass hybrids, and hybrid corn (Zea mays) produce a substantial amount of warm-season forage during summer. Produced forage has been largely stored through baleage due to heavy dew and frequent rains and has been evaluated according to S. Korea’s newly implemented baleage commodity evaluation system. The system weighs 50% of its total grading points on moisture content because of its importance in deliverable DM content and desirable baleage fermentation; this has proved to be an effective method. Although further improvement is required for the future of forage production in South Korea, the current government-led forage production in rice fields has been able to alleviate some of the country’s shortage for quality hay.

These experiments were to investigate the variations of rye on forage quality, productivity and β-carotene concentration affected by maturity in Pyeongchang region. Limited information are available about how forage quality and β-carotene content are affected by various factors. Samples were collected from rye harvested every 5 days, from April 25 to May 31 (April 25, April 30, May 4, May 9, May 15, May 21, May 25 and May 31). Dry matter (DM) content, plant height, DM yield and total digestible nutrient (TDN) yield increased continuously with the progressed maturity. However, crude protein (CP) content, in vitro dry matter digestibility (IVDMD) and relative feed value (RFV) decreased markedly with the delay of harvesting, while TDN content decreased from April 25 till May 15, then followed by a stable fluctuation. Conversely, acid detergent fiber (ADF) and neutral detergent fiber (NDF) value increased and then fluctuated slightly after blooming stage. For quality of plant parts, stem contained the lowest CP content and RFV value, and the highest ADF and NDF contents compared with other parts, while the grain showed the higher CP, IVDMD, RFV and lower fiber contents than others. With the plant matured, leaf proportion decreased while stem and grain proportion increased, and feed value of all the three parts decreased till blooming stage and followed by a stable phase. β-carotene concentration showed its highest on jointing stage, and then fell down sharply on the sequential stages. In conclusion, harvest around May 15 (blooming) is proper for forage rye if directly consumed by livestock as green chop in Pyeongchang under the consideration of both nutritive yield and forage quality.