• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.733-745
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• 2021

Although waxy corn varieties developed after the 1980s show differences depending on development stages and conditions, studies on the characteristics of waxy corn during the growth stage are rare. The subject of this study was a field survey and unmanned aerial vehicle (UAV) image acquisition of four waxy corn varieties cultivated in Idam-ri, Gammul-myeon, Goesan-gun, Korea. The study was conducted in four stages at intervals of two weeks after planting in 2019. The growth characteristics of each of the four varieties were analyzed using growth curves obtained based on field survey and UAV imagery data. The characteristics of each growth stage of the four varieties of corn, as assessed using normalized difference vegetation index (NDVI) and plant height (P.H.) values, were as follows. The growth model was identified as a model in which three-parameter logistic (3PL) curves reflect the growth characteristics of corn well. In particular, it was found that the variations in growth rate shown by P.H. and NDVI values clearly explain the differences between corn varieties. Among the four cultivars, growth and development first occurred at the early vegetative stage in Daehakchal, followed by Mibaek 2, Miheukchal, and finally Hwanggeummatchal. The variationsin P.H. and NDVI were achieved quickly and earlier in Daehakchal, followed by Mibaek 2, Hwanggeummatchal, and Miheukchal. It was confirmed that these results reflected the characteristics of the fast white-type varieties, while the black-type varieties were delayed, as in a previous study. These results reflect the resistance to lodging that affects the cultivation environment and the response characteristics to nutrients and moisture. It was confirmed that UAV accurately provides growth information that is very useful for analyzing the growth characteristics of each corn variety.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.3
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• pp.180-187
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• 2021

This study was performed to assess Protaetia brevitarsis larva excrement as an organic fertilizer for corn cultivation. Furthermore, the study investigated insect communities in each treatment. In 2009, the corn growth rate was worst in soil treated with P. brevitarsis larva excrement and in 2010, the corn growth rate was worst in untreated soil. From the outcome of the study, P. brevitarsis larva excrement could be utilized as organic fertilizer for corn cultivation.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.5
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• pp.452-461
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• 2017

This study was conducted to select an optimal approach to corn waste biochar (BC) application, and to evaluate the effects of combined application of BC and inorganic fertilizer (IF) on corn growth and soil chemical properties in a pot experiment. Corn growth differed with BC application timing and BC application levels. Based on the characteristics of corn growth in pot-based experiments, the selected optimal application conditions of BC were application of $500kg\;10a^{-1}$ at 20 days before sowing. Also, the chemical properties of the tested soil with BC after corn harvesting were significantly improved than those in the other treatments. In particular, soil pH and CEC regardless of application conditions were markedly increased by 0.04~0.19 units and $0.08{\sim}2.58coml_c\;kg^{-1}$ in BC treatments than without BC treatments. Additionally, combined application of BC and IF had greater effects on corn growth than single application of BC. Therefore, the results suggest using properly BC application conditions and a combination of BC and IF for effective corn cultivation in an upland field.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.224-230
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• 2001

This study was conducted to evaluate the extruding effects of corn and wheat on growth performance and fecal digestibility of amino acids in early-weaned pigs. Ground corn and wheat by a hammer mill (3 mm screen in diameter) were extruded at $130{\pm}2^{\circ}C$ with a moist-type extruder ($Matador^{(R)}$). Treatments were: 1) 3 mm ground corn, 2) extruded corn, 3) 3 mm ground wheat, and 4) extruded wheat. A total of 160 pigs (14 d of age and $4.3{\pm}0.74kg$ BW) were allotted with the dietary treatments for a 21-d feeding trial. All diets were mash and contained 30% corn or wheat products. For a digestibility trial, 16 pigs (14-d old and $4.2{\pm}0.32kg$ BW) were employed in individual metabolic crates. There were no differences (p>0.15) in growth performance between corn-fed and wheat-fed groups. Feeding pigs diets containing extruded corn or wheat did not affect ADG (p>0.15) and ADFI (p>0.15), but it improved feed/gain (p<0.01). Also, feeding pigs diets containing extruded corn or wheat had lower true fecal digestibilities of arginine, histidine, isoleucine, lysine and valine (p<.007) in the pigs. In conclusion, our results suggest that extruding corn and wheat had no benefit on the growth of early-weaned pigs.

• 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.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.291-298
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• 1996

This study was carried out at Crop Experiment Station in 1993 and 1994. The objective of this study was finding out variation of growth and yield of corn according to maturity. Hybrids of corn used in this study were early maturing corn Comet80, Elite90, Royaldent IOOT, Royaldent T$\times$llO, P3525, P3394, medium maturing corn Royaldent 120T. and late maturing corn Jungbuok, P3144W. G4743. Stalk height, leaf number, ear weight, stover weight, and TDN yield of early maturing corn were linearly increased with prolonged maturity in 1993 growing season. Leaf number, and stover weight of early and late maturing corn were linearly increased with prolonged maturity in 1994 growing season. But ear weight of late manuring corn was not increased as much as that of early manuring corn with prolonged maturity. Increase of total DM and TDN yield of late maturing corn was due to stover weight increase compared with ear weight increase of early maturing corn. Leaf number and stover weight were highly correlated with silk (Growing Degree Days) GDD.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.1
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• pp.43-48
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• 1998

No-tillage silage corn with legume hairy vetch(Vicia villosa Roth, HV) has renewed interest in supply of mineral N, soil erosion control at sloping land and weed control by cover of HV killed. This study was conducted to monitor concentration of soil mineral N ($NO_3^-$ -N + $NH_4^+$-N) and to find out variation of growth, yield and N uptake of silage corn according to quantity of HV cover; HV-removed, 1X-HV, 2X-HV at field of Crop Experiment Station in 1996. HV groM in early spring decreased the mineral N of soil depth 7.5 -22cm before corn seeding. But, killed HV cover increased the concentration of soil mineral N at surface soil (0-7.5cm) up to 45.4mglkg at early growth stage of corn. Dry matter(Dh4) of corn at harvest was lower in W-removed than in Okg FNlha. But DM and N uptake of corn at harvest were increased by quantity of HV-cover increasing liom HV-removed to 2X-HV. Hairy vetch could substitute N fertilizer for silage corn by N mineralized h m HV killed, but reduced early growth and N uptake of corn before silk by reducing soil mineral N of plow layer.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1035-1040
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• 2003

This experiment was conducted to investigate the effects of fat sources on growth performance, nutrient digestibility, serum traits and intestinal morphology in weaning pigs. A total of 128 weaning pigs (Landrace${\times}$Large White${\times}$Duroc, $21{\pm}2$ days of age, $5.82{\pm}0.13kg$ of average initial body weight) were allotted in a randomized complete block (RCB) design with four treatments: 1) corn oil, 2) soybean oil, 3) tallow and 4) fish oil. Each treatment had 8 replicates with 4 pigs per pen. During phase I period (d 0 to 14), pigs fed corn oil or soybean oil diet tended to show higher ADG and FCR than any other treatments although there was no significant difference. During phase II period (d 15 to 28), pigs fed corn oil diet showed better ADG and ADFI than pigs fed soybean oil, tallow or fish oil. For overall period, growth performance of weaning pigs was improved (p<0.05) when pigs were fed soybean oil or corn oil. Apparent digestibility of energy and fat was improved when pigs were fed corn oil diet (p<0.05). Supplementation of corn oil resulted in higher serum triglyceride concentration than the other treatments (p<0.05). However, there was a lower cholesterol concentration when corn oil was provided compared to tallow or fish oil. Pigs fed corn oil tended to have increased villus height compared with soybean oil, tallow or fish oil treatment (p<0.05). This experiment suggested that vegetable oils such as corn oil or soybean oil, were much better fat source for improving growth performance of weaning pigs.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.2
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• pp.122-131
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• 1993

This study was conducted in 1991 and 1992 to determine the effects of winter annual forage corps such as winter rye (Secale cereale L.), rape (Brassica napus subsp. oleifera L.), oats (Auena satiua L.), crimson clover (Trifolium incarnatum L.), vetch (Vicia satiua L.) and Italian ryegrass (Lolim multiflorum Lam.) on subsequent growth, yield and quality of silage corn (Zea mays L.). The winter annual forage crops were seeded at the end of August and harvested in the fall and spring before corn planting. Corn-leaf numbers, plant heights and LA1 were generally reduced during early development when corn followed Italian ryegrass(P<0.05) and winter rye, but the silking date of corn was not affected by the winter annual forage crops. Corn dry matter and TDN yields were significantly reduced when corn followed Italian ryegrass and late maturing Kodiak winter rye. The yield reductions for corn following Italian ryegrass and Kodiak winter rye, relative to corn which did not follow the winter annual forage crops, were 49 and 19% respectively. but the corn yield was slightly improved by 2 and 3%, respectively. when corn followed crimson clover and vetch. No quality differences in corn stover were observed among the treatments except for the lowest ADF and NDF contents and the highest IVDMD where corn followed ltaliabn ryegrass.