Yield and Nitrogen Uptake of Corn in Corn after Soybean Cropping

Seo, Jong-Ho,Lee, Ho-Jin,Lee, Jin-Wook The Korean Society of Crop Science 2001 Korean journal of crop science Vol.46 No.4

Soybean can produce high-N residue due to N-fixation, so soybean rotation may increase yield of subsequent corn and reduce N fertilizer on the corn fairly. To find out the contribution of nitrogen to subsequent corn following soybean cultivation, soil nitrate, corn yield, and nitrogen uptake were measured for three continuous corn cropping years after soybean rotation. Three N rates of 0, 80, and 160 kg/ha were applied to three continuous corn following soybean cropping. At 6-leaf stage, soil nitrate amount at the soil depth of 0-30cm ranged from 60 to 80 kgN/ha higher in the first corn cropping year than that in the second and third corn cropping years. Judging from corn N status such as SPAD value, N concentration of ear-leaf and stover at silking stage, N contribution of previous soybean to corn in the first corn year was N fertilizer of approximately 80 kg N/ha. Stover N uptake at silking stage increased from 47 to 52 kg N/ha at the 0, and 80 kg N/ha of N rates in the first corn cropping year compared with those in the second and third corn cropping years. Corn grain yield at the 0 kg N/ha of N rate was 6-7 ton/ha higher in the first corn cropping year than that in the second and third corn cropping years, respectively. When compared the first corn year following soybean cropping with the second and third corn cropping years, N uptake of grain and stover at harvest with low N rates such as 0 and 80 kg N/ha increased from 45 to 67kg N/ha, from 35 to 60 kg N/ha, respectively. N uptake of whole plant by soybean rotation increased from 93 to 118 kg N/ha in the first year compared with that in the second and third corn cropping years. However, the N contribution by soybean cropping was small in the second and third continuous corn cropping years. Therefore, it was concluded that the nitrogen fertilizer of 80-100 kg N/ha in the first corn cropping year could be saved by soybean rotation and annual alternative corn-soybean rotation could be the best rotation system.

Nursing Method with Polypropylene Spunbonded Fabric in Rice

Hong, Kwang-Pyo,Kim, Jang-Yong,Kang, Dong-Ju,Kim, Yeong-Gwang,Joung, Wan-Kyu,Song, Geun-Woo,Choe, Zhin-Ryong The Korean Society of Crop Science 2000 Korean journal of crop science Vol.45 No.2

An extensive investigation has been made for the possible utilization of polypropylene spunbonded fabrics in rice seedling nursery. Considering the cropping systems available in southern part of Korea, sowing dates were fixed at April 5 and April 20 for single cropping and May 6 and May 26 for double cropping. Nursery period was fixed to 35 days for each sowing date. Four different thickness of polypropylene spunbonded fabrics, 40, 60, 80, 100 g/$m^2$, were tested in rice seedling nursery. The temperature and light intensity were not significantly different among the thickness of polypropylene spunbonded fabrics. Light intensity was significantly reduced in polypropylene spunbonded fabric (72.2 Klux) compared with polyethylene mm (85.5 Klux), however, the reduced light intensity was enough for seedling growth. The temperature in the polypropylene spunbonded fabric covering during low air temperature was higher than that in polyethylene mm tunnel. At transplanting, the rice seedlings grown in polypropylene spunbonded fabric condition was shorter (17cm) but healthier than those in polyethylene mm (23cm). The estimated possible nursery periods using the polypropylene spunbonded fabric covering may start from April 1 at Chinju (plain area in Southern Korea, 20m altitude) and April 15 at Susang (mountainous area, 430m altitude). Labour hours and cost were reduced by about 28% and 48%, respectively.

Influence of Light on Biomass of Soybean in Narrow Strip Cropping of Oat, Corn, and Soybean

Van, Kyujung The Korean Society of Crop Science 2002 Korean journal of crop science Vol.47 No.5

The strip intercropping system has used due to many advantages. Many researches supported these crop systems are usually equal to or better than monoculture crop systems in both total production and profit. There was no research to examine the important ecological factors in the competition between crops. A strip intercropping system composed of adjacent narrow strips of corn, soybean, and oat/legumes has been investigated in Iowa, USA. This study conducted to investigate why and how the differences in soybean yield are produced and affected by light, one of the microclimate, of the strip intercropping system. In height, the two rows of soybean closest to corn were taller than the two rows near the then-empty oat strip. The height of each crop decreased as the amount of light received increased. Weight of plant parts was lowest in row 1, nearest corn, and highest in row 4, next to the vacant oat strip. Daily photon flux density(PFD) increased with increasing distance from corn, with the highest value occurring on the edge next to the empty oat strip. Analyses of the relationship between light and biomass of soybean showed that all biomass measurements had a positive relationship to total PFD per day except height.

Screening of Insecticide to Control Rhophalosiphum nymphaeae for Alisma plantago as Second Crop in Paddy Field

Kwon, Byung-Sun,Lim, June-Taeg,Shin, Jeong-Sik The Korean Society of Crop Science 2003 Korean journal of crop science Vol.48 No.1

The purpose of this study was to evaluate the effect of pesticides on insect pest control of Rhophalosiphum nymphaeae, growth characteristies and dry root yield from the cultivated after early maturing rice cropping. All pesticides treated had no effect on the growh period, flowering rate of Alisma plantago. The major pesticides were methomyl-Lf, 24.1 %, imidacloprid-Wp, 10%, carbosulfan-Wp, 20%, and methomyl-Wp, 45%. Dry yield of root were increased largely with imidacloprid-Wp, 10% (10g/20$\ell$), pesticide than the other pesticides and control. All pesticides were had no injury with recommended concentration. On the other hand all pesticides were slightly harmful in the double dosage level for the Alisma plantago.

Conservation of Biodiversity and Its Ecological Importance of Korean Paddy Field

Cho, Young-Son,Lee, Dong-Kyu,Choe, Zhin-Ryong,Han, Min-Soo,Pellerin, Kristie The Korean Society of Crop Science 2006 Korean journal of crop science Vol.51 No.6

Biodiversity is closely related to the conservation of ecosystems. Ecosystems provide more subtle, but equally essential, services. Microorganisms decompose human's waste and renew the soils that produce our food crops. Biodiversity in Korean paddies encompass 54 families and 107 species of freshwater invertebrates. In terms of the number of aquatic insects affected by different sources, the order starting with the highest population was swine slurry > chemical fertilizer > fresh straw with reduced fertilizers > control. The number of freshwater invertebrate and aquatic macro-invertebrate in surface water of the plots without insecticidal application were 2 and 2.1 times greater than in fields receiving insecticide applications, respectively. The soil microfungal flora of the 85 isolates paddy fields in Korea was 30 species in 13 genera and 11 isolates were unidentified yet. Agricultural policy should be changed to assist the conservation of biodiversity because until now the agricultural ecosystems have been negatively affected from the development of high-yield varieties to enhance food production, and the expansion of fertilizer and chemical use. For the conservation of agricultural ecosystems, agricultural practices with less investment and more resource saving, as well as enhancing the safety of agricultural and livestock products are essential. Finally, this paper was written for the contribution for the development of environmentally friendly farming systems with neighboring or whole ecosystems.

Long-Term Study of Weather Effects on Soybean Seed Composition

Bennett John O.,Krishnan Hari B. The Korean Society of Crop Science 2005 Korean journal of crop science Vol.50 No.1

A long-term study initiated in 1989 at San-born Field, Columbia, Missouri, was designed to evaluate the affect of environmental factors, nitrogen application, and crop rotation on soybean (Glycine max [L.] Merr.) seed composition. Soybeans were grown as part of a four- year rotation which included corn (Zea maize L.), wheat (Triticum aestivum L.), and red clover (Trifolium pratense L.). Results from soil tests made prior to initiation of the study and subsequently every five years, were used to calculate application rates of nitrogen, phosphorus, and potassium necessary for target yield of pursuant crops. In the experimental design, nitrogen was applied to one-half of the plot on which the non-leguminous crop, either corn or wheat was grown. Analysis of soybean seed by near infrared reflectance spectroscopy collected over an 11-year period revealed a linear increase in protein and decrease in oil content. Application of nitrogen fertilizer to non-leguminous crops did not have an apparent effect on total protein or oil content of subsequent soybean crop. Analysis of soybean seed proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis in conjunction with computer­assisted densitometry revealed subtle changes in the accumulation of seed proteins. Immunoblot analysis using antibodies raised against the $\beta-subunit$ of $\beta-conglycinin$ showed a gradual increase in the accumulation of the 7S components during successive years of the experiment. A linear increase in temperature and decrease in rainfall was observed from the onset of data· collection. Higher temperatures during the growing season have been linked to increased protein and diminished oil content of soybean, thus changes observed in this study are possibly related to climatic conditions. However, crop rotation and subsequent changes in soil ecology may contribute to these observed changes in the seed composition.

Chemical Control of Brown Leaf Blight in Alisma plantago Double Cropping after Early Rice

Shin, Jong-Sup,Kwon, Byung-Sun,Park, Hee-Jin The Korean Society of Crop Science 2001 Korean journal of crop science Vol.46 No.5

This study was conducted to evaluate the control effect of fungicides on control of brown leaf blight, growth characteristics, and dry root yield in the cultivation of Alisma plantago after early maturing rice cropping. All fungicides treated had no effect on the growth and flowering rate of Alisma plantago. The major fungicides were mancozeb Wp, 75%, chlorothalonil Wp, 75%, dithianon Wp, 43%, difenoconazole Wp, 10%, benomyl Wp, 50%, and propineb Wp, 70%. Dry root of yield were increased largely with chlorothalonil Wp, 75%(33 g/20), fungicide than the other fungicides and control. All fungicides had no injury with standard dosage. On the other hand all fungicides had slight injury in the double dosage level for the Alisma plantago.

An Ultrastructural Investigation of Infection Threads in Sesbania rostrata Stem Nodules Induced by Sinorhizobium sp. Strain MUS10

Krishnan Hari B. The Korean Society of Crop Science 2004 Korean journal of crop science Vol.49 No.4

Sinorhizobium sp. strain MUS10 forms nitrogen-fixing stem nodules on Sesbania rostrata, a tropical green manure crop. In this study, the ultrastructural events associated with the formation of stem nodules were investigated. Sinorhizobium sp. strain MUS10 entered the host tissue through cracks created by the emerging adventitious root primordia and multiplied within the intercellular spaces. During early phases of infection, host cells adjacent to invading bacteria revealed cellular damage that is typical of hypersensitive reactions, while the cells at the inner cortex exhibited meristematic activity. Infection threads were numerous in S-day-old nodules and often were associated with the host cell wall. In several cases, more than one infection thread was found in individual cells. The junction at which the host cell walls converged was often enlarged due to fusion of intracellular branches of infection threads resulting in large infection pockets. The infection threads were made up of a homogeneous, amorphous matrix that enclosed the bacteria. Several finger-like projections were seen radiating from these enlarged infection threads and were delineated from the host cytoplasm by the plasma membrane. As in Azorhizobium caulinodans induced root nodules, the release of Sinorhizobia from the infection threads into the plant cells appears to be mediated by 'infection droplets'. A 15-day­old Sesbania stem nodule revealed typical ultrastructure features of a determinate nodule, containing several bacterioids within symbiosomes.

Effects of Plant Types and Cultivars on Pod Yield in Late Seeding Peanut

Pae, Suk-Bok,Kim, Jung-Tae,Shim, Kang-Bo,Hwang, Chung-Dong,Chung, Chan-Sik,Lee, Myung-Hee,Park, Keum-Yong The Korean Society of Crop Science 2007 Korean journal of crop science Vol.52 No.1

This experiments were conducted to evaluate suitable plant-type and cultivars for producing fresh pod peanut from late seeding as succeeding crop, compared with early seeding as proceeding crop or single cropping. 12 cultivars according to grain weight and plant types, 6 virginia typed cultivars(ssp. hypogaea) and 6 shinpung typed cultivars(ssp. fastigiata), were used for early and late seedings. The plant growth and yield potential in early seeding were better than those in late seeding. But the ratios of dry/fresh pod and of mature pod in late seeding were higher than those of early seeding. The yield of fresh pod by cultivars in two seeding times showed significant correlation with pod scale such as fresh pod weight, 100-grain weight, and dry seed yield positively, but pod number negatively in early seeding only. Yield of fresh peanut between Virginia and Shinpung types didn't show significant difference in early seeding, but showed in late seeding. Average yield of Virginia typed cultivars showed significantly higher than that of Shinpung typed ones. This yield gap between two plant types was the same tendency on extending seedings to July 20.

Identification of Granule Bound Starch Synthase (GBSS) Isoforms in Wheat

Seo, Yong-Weon,Hong, Byung-Hee,Ha, Yong-Woong The Korean Society of Crop Science 1998 Korean journal of crop science Vol.43 No.2

Granule bound starch synthase (GBSS), also known as the '"waxy protein'", is responsible for the synthesis of amylose in the amyloplasts of cereal crops. In hexaploid wheat (Triticum aestivum L.), GBSS is involved in amylose synthesis and rolls as an important factor to determine flour quality and end-use quality in food products. Genes on three Wx loci have been found to encode GBSS in common wheats. We developed techniques for the purification and separation of GBSS in wheat. Three major GBSS isoforms, which were encoded by the genes on three loci, Wx-A1, Wx-B1, and Wx-D1 migrating differently by one dimensional SDS-po-lyacrylamide gel electrophoresis (1D SDS-PAGE), were identified. GBSS from 66 Korean hard and soft winter wheats were purified and determined for their Wx loci and four of them were identified possessing a null allele either at the Wx-A1 and Wx-B1 loci. With help of identification of three GBSS isoforms using 1D SDS-PAGE system, we are able to identify and monitor Wx gene expressions in breeding materials for developing waxy or partial waxy wheats without experiencing consecutive selecting generations.cting generations.