• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.614-621
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• 2012

Although there is a broad dispute over genetically modified foods on safety, the worldwide adoption of transgenic crops is rapidly increasing. The objectives of this study were to identify trends in the effects of transgenic on crop yields and examine the effect of agricultural variables including crop type, biotech trait, tillage system, and yield environment on corn and soybean yield. A meta-analysis from the 34 peer-reviewed scientific literatures was conducted to compare the crop yield between transgenic crops and conventional varieties. Results showed that the yield of transgenic corn and soybean was strongly dependent on growing conditions. Transgenic hybrids had higher yield potential in the low crop yield environments such as high weeds and/or insect infestation, low soil water, and cool temperature conditions, while transgenic crops did not have yield advantages in high yield environments. The results from this study suggest that producers should consider the potential yield environmental conditions and possible yield reductions when producers choose crop hybrids in their fields.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.224-232
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• 2019

Objective: Apart from various climatic differences, corn harvest stage and varieties are two major factors that can influence the yield and quality of corn silage in the tropics. A study was conducted to determine the optimum harvest stage of four corn varieties for silage production in Malaysia. Methods: Corn was harvested at four growth stages; silking, milk, dough, and dent stages from four varieties; Sweet Corn hybrid 926, Suwan, breeding test line (BTL) 1 and BTL 2. Using a split plot design, the treatments were then analysed based on the plant growth performance, yield, nutritive and feeding values followed by a financial feasibility study for potential commercialization. Results: Significant differences and interactions were detected across the parameters suggesting varying responses among the varieties towards the harvest stages. Sweet Corn was best harvested early in the dough stage due to high dry matter (DM) yield, digestible nutrient, and energy content with low fibre portion. Suwan was recommended to be harvested at the dent stage when it gave the highest DM yield with optimum digestible nutrient and energy content with low acid detergent fibre. BTL 1 and BTL 2 varieties can either be harvested at dough or dent stages as the crude protein, crude fibre, DM yield, DM content, digestible nutrient and energy were not significantly different at either stage. Further financial analysis showed that only Sweet Corn production was not financially feasible while Suwan had the best financial appraisal values among the grain varieties. Conclusion: In conclusion, only the grain varieties tested had the potential for silage making according to their optimum harvest stage but Suwan is highly recommended for commercialization as it was the most profitable.

• Journal of The Korean Society of Grassland and Forage Science
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• v.32 no.3
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• pp.285-292
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• 2012

This experiment was carried out to determine the harvesting day after heading of barley for highest total forage yield in double cropping with corn at paddy field in middle region. The fresh barley yield was the highest at the harvest of 20 days after heading, but the dry matter yield and TDN yield were the highest at the harvest of 25 days after heading because of higher dry matter rate. The dry matter yield of corn after the harvest of 25 days after heading was decreased about 16 percent than that of the check, sowing on april 25. But total fresh yield of corn monoculture was lower about 31 percent, and decreased 28 percent of dry matter and 23 percent of TDN yield, respectively, than that of the double cropping system with corn and barley. In double cropping system at paddy field, the total forage yield was the highest at the harvest of 25 days after heading of barley and grew corn subsequently. Although yield of corn was reduced by late sowing, the total forage yield was increased by double cropping system compared with corn monoculture.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.324-324
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• 2017

Total 15 different corn hybrids, Kwangpyeongok, Gangdaok, Yanganok, Singwangok, Jangdaok, Cheonganok, Cheongdaok, Andaok, Dapyeongok, Pyeongkangok, Pyeonganok, Daanok, Sunwon P3394, Gangilok, P3394, had been used to investigate the plant growth and yield of corn hybrids depends on the sowing date. Sowing dates were April 5th, June 25th, and July 5th and all experiments had three repeats. The growth of Gangdaok was the best. However, in the case of Kwangpyeongok, the growth was not the best to compare with Gangdaok, but the stem to ear height ratio was lower than Gangdaok, it may be better for the stable cultivation. Both of the growth and yield of Daanok was not good regardless of planting date, but the yield and ear shape of Pyeongkangok and Dapyeongok were good for fresh corn. The growth and yield of 15 different corn hybrids were variable depends on the planting date, however, the growth degree days (GDD) was the most important factor for the maturity of the corn. More than $1500^{\circ}C$ of GDD was enough to harvest mature corn hybrids in the central region of Korea. Besides the yield and growth, other characters such as sweetness and taste as a food should be investigated further for the fresh corn to be suggested.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.2
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• pp.92-99
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• 2014

The crop growing conditions make accurate predictions of yield ahead of harvest time difficult. Such predictions are needed by the government to estimate, ahead of time, the amount of crop required to be imported to meet the expected domestic shortfall. Corn and soybean especially are widely cultivated throughout the world and a staple food in many regions of the world. On the other hand, the CASA (Carnegie-Ames-Stanford Approach) model is a process-based model to estimate the land plant NPP (Net Primary Productivity) based on the plant growing mechanism. In this paper, therefore, a methodology for the estimation of corn/soybean yield ahead of harvest time is developed specifically for the growing conditions particular to Iowa and Illinois. The method is based on CASA model using MODIS data, and uses Net Primary Productivity (NPP) to predict corn/soybean yield. As a result, NPP at DOY 217 (in Illinois) and DOY 241 (in Iowa) tend to have high correlation with corn/soybean yields. The corn/soybean yields of Iowa in 2013 was estimated to be 11.24/3.55 ton/ha and Illinois was estimated to be 10.09/3.06 ton/ha. Errors were 6.06/17.58% and -10.64/-7.07%, respectively, compared with the yield forecast of the USDA. Crop yield distributions in 2013 were presented to show spatial variability in the state. This leads to the conclusion that NPP changes in the crop field were well reflected crop yield in this study.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.518-518
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• 2016

Agriculture is the lifeblood of the economy in Ghana, employs about 42% of the population work force and accounts for 30% of the Gross Domestic Product (GDP). Corn (maize) is the major cereal crop grown as staple food under rain fed conditions, covers over 92% of the total agricultural area, and contributes 54% of the caloric intake. Issues of hunger and food insecurity for the entire nation are associated with corn scarcity and low production. The climate changes are expected to affect corn production in Ghana. This study evaluated variations of corn yields based on different climate conditions of rain-fed area in the Dangbe East District of Ghana. AquaCrop model has been used to simulate corn growing cycles in study area for this purpose. The main goal for this study was to predict yield of corn using selected climatic parameters from 1992 to 2013 using different climate scenarios. The Model was calibrated and validated using observed field data, and the simulated grain yields matched well with observed values for the season under production giving an R squared (R2)of 0.93 and Nash-Sutcliff Error(NSE) of 0.21. Study results showed that rainfall reduction in the range of -5% to -20% would reduce the yield from 1.315ton/ha to 0.421ton/ha (-21. 3%) whereas increasing temperature from 1% to 7% would result in the maximum yield reduction of -20.6% (1.315 to 1.09 ton/ha.). On the other hand, increasing rainfall from 5-20% resulted in yield increment of 68% (1.315-2.209 ton/ha) and decreasing temperature produce 7% increase in yield ( 1.315 to 1.401ton/ha). These results provide useful information to adopt strategies by the Government of Ghana and farmers for improving national food security under climate change.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.384-389
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• 2002

No-tillage (NT) practice for corn production has advantages of reduction of soil erosion and energy conservation. Research on effects of NT for sweet corn or super sweet corn is very limited. Hybrids of sugary (su) and shrunken-2 (sh2) were tested under NT and conventional tillage (CT) practices to investigate plant characters, ear characters, fresh yield, and grain yield. Sugary hybrids were Golden Cross Bantam 70 (GCB70), Sprint, Geumdanok, and Danok3. Shrunken-2 hybrids were BSS9472, Cambella90, GSS9299, Jubilee, KS-Y-65, and Chodangok1. Emergence rates under NT were lower than those under CT for su, while there was no difference between tillage systems for sh2. There were no differences between CT and NT for days to tasseling and silking, plant height, and ear height for both su and sh2. Ear characters such as ear length, number of kernel rows, number of kernels per row, and t100-kernel weight under NT were not significantly different from those under CT. There were no differences between two tillage practice for fresh and grain yield, rather they showed trend of increases under NT practices. Results from this trial indicate that NT practice for both su and sh2 cultivation may be possible to recommend to farmers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.3
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• pp.141-147
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• 2019

The purpose of this study was to determine the effect of waterlogging duration on the growth characteristics and productivity of forage corn at different growth stages under paddy field conditions. Treatments consisted of waterlogging at two growth stages (V7 or V14) for four waterlogging durations (no waterlogging, 48 hours, 72 hours, and 96 hours, respectively). The V14 growth stage was more vulnerable to waterlogging than the V7 stage. Among the waterlogging durations, the lodging score increased at 48 hours. The stem height of forage corn decreased with the increase in waterlogging duration at the different growth stages (V7 and V14). Increase in waterlogging duration reduced the stem dry matter yield, ear dry matter yield, and total dry matter yield at both growing stages (V7 and V14). The waterlogging treatments at the V14 stage affected ear dry matter yield more than those at the V7 growing stage. Thus, the management of forage corn under paddy field conditions must be strengthened during early (V7) and grain fill stages (V14). When waterlogging occurs, surface and subsurface drainage should be implemented within 48 hours to control (no waterlogging) the groundwater level and, thus, minimize economic losses due to forage corn damage.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.3
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• pp.217-222
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• 1998

This experiment was carried out to investigate effects of herbicide application method on Calysteria jcqoonica control and corn yield at the forage experimental field, grassland and forage crops division, National Livestock Research Institute, RDA, Suwon from 1996 to 1997. The experiment was arranged in a randomized block design with three replication. The herbicide application consisted of control, 2~3 leaf stage(Dicamba), 5~6 leaf stage(Dicamba) and soil treatment (Pendimethalin). The hybrid of corn used in this experiment was P 3352. The results obtained are summarized as follow; 1. The plant height was the lowest at control and the highest at Dicamba treatment in 5~6 leaf stage, but no significant difference was found among herbicide application method at ear height. Tasseling and silking date were delayed 2~3 day at control. The length and weight of ear were highest at Dicamba treatment in 2~3 leaf stage. 2. The herbicide injury of corn was very slightly after 10-20 day, but corn was recovered soon. The weed control value was 94.2~67.5% at herbicide application plot. 3. The fresh and dry matter yield of Dicamba treatment in 2-3 leaf stage was highest as 42,878 and 16,033kg/ha, respectively. The application of Dicamba increased the DM yield of corn by 13~30%. 4. Herbicide application time had little effect on the ADF, NDF and CP contents, but the forage quality of ear was higher than that of stover. The result of this experiment indicate that the application of Dicamba in 2~6 leaf stage of corn will remove almost all of Calysreria jqonica and increase DM yield of com.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.1
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• pp.59-66
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• 1997

This experiment was conducted at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon in 1992 and 1993 to investigate the effects of tillage method-conventional and rotary-till, rye (Secde cereale L.) harvest date-early (April 14) and late (April 26), and rye residue treatmentno paraquat(1, 1-dinethyl-4,4'-bipyridinium dichloride) and paraquat in minimizing the adverse effects of the rye residue on growth and yield of succeeding corn(Zea mays L.). Corn plant height during the growing season was slighly taller with conventional tillage relative to rotary-till when rye was harvested in early and treated by paraquat. Corn LA1 during the growing season was slighly increased when rye was harvested in early and where conventional tillage was used with paraquat treatment. There were no differences in the leaf number and silking dates of corn among the tillage methods, harvest dates of rye and paraquat treatments. The dry matter yield of corn was significantly increased by paraquat treatment when rye was harvest in early, but no differences were found in the dry matter percentage, ear percent to total dry matter, and stover, ear and estimated TDN yields of corn among the treatments.