• Korean Journal of Organic Agriculture
• /
• v.13 no.2
• /
• pp.211-221
• /
• 2005

This experiment was conducted to evaluate the effect of animal slurry on nitrogen uptake of hairy vetch and growth of chinese cabbage in cropping system. Hairy vetch was seeded on September 20 in 2003 . We examined the effect of cover crop(hairy vetch (Vicia villosa Roth) and slurry application(0, l00, 200kg N/ha) on yield and N uptake. Dry matter yield and nitrogen uptake of hairy vetch were measured. The chinese cabbage succeeding cover crop was harvested in 2004. The nitrogen uptake of hairy vetch was 84, 121, 148kg N/ha respectively, when the slurry application was 0, 100 and 200kg N/ha. In addition. N uptake of hairy vetch at the plot of 100kg and 200 kg N/ha slurry were 44% and 76% higher than that of the plot without slurry application respectively. Slurry application of hairy vetch could increase nitrogen uptake by application of green manure at the harvesting time. the content of organic matter and P-content of soil with hairy vetch plot was higher than that of fallow plot due to inhibition of soil erosion. The organic matter levels tend to improve with the addition of hairy vetch. Hairy vetch could improve soil quality by reducing erosion compared with bare fallow. The green manure of hairy vetch with animal slurry maintained soil nutrient and reduced nitrogen fertilizer of chinese cabbage. The hairy vetch residues decomposed rapidly releasing half of their residues within 40 days after burial. The yield of chinese cabbage was 90% in the plot of manure of hairy vetch compared with chemical fertilizer. The yield in the plot treated with green manure of hairy vetch and 50% of chemical fertilizer was reduced 5% less than that of chemical fertilizer. Therefore, it was estimated that the green manure of hairy vetch-chinese cabbage cropping system could reduce nitrogen chemical fertilizer as much as 84~148kgN/ha. the green manure of hairy vetch with animal slurry maintained soil nutrient and reduced nitrogen fertilizer of chinese cabbage.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1999.06a
• /
• pp.21-38
• /
• 1999

Herbicide is an essential agricultural chemical in the modern agriculture. Due to its bioactivity, however, risk of herbicide use against non-target organisms should be seriously considered. Among the unfavorable aspects given by herbicide, the residue is the most important because herbicide residue in soil and agricultural product is closely related to human safety. The residue in soil and crop is dependent on conditions of soil, weather, herbicide use and crop cultivation, etc. In general, the residue in soil or agricultural product in Korea is known to be not serious at this moment, except for some problems like carry-over effect on succeeding crops. To secure safety of herbicide use for the health, soil ecology and other environment, researches on herbicide residue including monitoring survey should be done more frequently and extensively. Safety guide for herbicide usage should be kept by farmers and development of long toxic herbicide should be accelerated.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.46 no.3
• /
• pp.253-259
• /
• 2001

The purpose of this study was loused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when N fertilizer (urea) and mature compost were applied. Lysimeters (volume 0.15㎥, diameter 62cm, height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments: fellow, fellow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications (16, 32, and 64 kg/10a), three N fertilizer and compost soil surface applications (16+800i 32+1600, and 64+3200 kg/10a), two water dissolved N fertilizer applications(16 and 32 kg/10a), and low and high plant densities. The growth of corn (preceding crop) and potatoes (succeeding crop) and leaching loss were determined during the experimental period. The amount of leachate from lysimeter was remarkably greater at bare conditions than at cropping conditions for corn and potatoes. The N content of plants (corn and potatoes) tended to increase as fertilizer rate increased. Fertilization of urea dissolved in water to soil was more efficient than surface fertilization for the growth, yield, and the N uptake N of corn and potatoes. There were no differences in dry matter yield of plants between medium and high N rates, but N, Ca, K and Mg concentrations of plants were higher at higher N rates. There were significant correlations between N uptake and each of Ca, K and Mg uptakes in corn and potatoes. Total N uptake by plants increased with increased N fertilizer and compost applications. Plane absorbed 54.9% of applied N at low N rate and 31.0 to 34.0% at high N rates. The proportion of N leaching losses was lower at low N rate and high plant density.

• Korean Journal of Weed Science
• /
• v.31 no.1
• /
• pp.34-40
• /
• 2011

Cover crop can be used to suppress weeds by competition for light and nutrient. Objective of this study was to evaluate the effectiveness of legume cover crops on change of weed community in no-till corn cultivation. Two legume cover crops, hairy vetch and crimson clover were grown in the field, and succeeding corn was sown on 4 May, 2010. The distribution of weed was surveyed at 15 April, 1 June, and 20 August. At 15 April, the weed biomass in hairy vetch field was higher than in crimson clover field. The dominant weeds were Capsella bursa-pastoris L. and Stellaria aquatica L. in hairy vetch and crimson clover fields, respectively. At vegetative stage of corn, occurred weeds in hairy vetch and crimson clover fields were four and six species, respectively, while the weed was occurred with nine species in conventional. Also the dry weight of weed was decreased by 82 and 75% in hairy vetch and crimson clover fields compared to conventional. On the other hand, after harvest of corn, occurred weed in hairy vetch, crimson clover and conventional was five, four and five species, respectively. Dry weight percentage of occurred weed in conventional was 23.5%, and the value was higher than 13.8 and 14.7% in hairy vetch and crimson clover fields, respectively. Stellaria aquatica L. as winter annual weed only occurred in cover crop field during corn growing season. It is these possibilities that low soil temperature and light interception by soil cover of legume cover crop.

• Korean Journal of Organic Agriculture
• /
• v.22 no.4
• /
• pp.657-665
• /
• 2014

This study was carried out to study the effect of eggplant (EG203) grafting and strawberry removal time on succeeding tomato cropping in high temperature season. In non tillage culture, bacterial wilt incidence was 30% and 0% in nongrafting and eggplant (EG203) grafting while 25% in non-grafting and 0% in eggplant (EG203) grafting in tillage culture. Commercial yield was similar in tillage and non-tillage culture using EG-203 grafting as 2,693 kg/10a and 2,657 kg/10a respectively with no difference in soluble solid content and hardness. Strawberry removal time after tomato planting enhanced plant height and internode length in 20days and 30days later removal while no difference in other growth characters. Commercial yield was higher as 1,885 kg/10a in strawberry removal before tomato planting than 1,678 kg/10a in 30days later removal. From this research, strawberry removal time should be determined by considering strawberry price and growth and expecting profit by succeeding tomato cropping.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.17 no.3
• /
• pp.293-304
• /
• 1997

A field experiment was conducted at the forage experimental plots, Seoul National University, Suweon h m 1995 to 1996 to determine the effect of legume residues as a N source and N fertilizer on corn (Zea mays L.) silage yield, N uptake, and availability of inorganic N in the soil. Corn was grown following (i) red clover (Trifolium pratense L.), (ii) crimson clover (Trifolium incarnatum L.), (iii) alfalfa (Medicago sativa L.) and (iv) winter fallow. The plots were split into two rates of fertilizer N (0 and 90kg Nlha) in a split-plot experimental plan. Compared with fallow treatment, legumes depleted soil water in the surface 15cm at corn planting by 17 to 26%. As a result, corn emergence was markedly delayed with legume residues by 8 to 11 days. Corn silage DM yield was significantly reduced in the presence of legume residues by 2.0 to 3.4 and 1.5 to 2.5 tonlha compared with winter fallow treatment at 0 and 90kg fertilizer Nlha, respectively, but no significant difference in the corn DM yield was found between legume residue treatments. There was an overall tendency for increased corn yields with 90kg fertilizer Nlha compared to Okg fertilizer Nlha, although not all yield increases were significantly greater. The corn yield response to applied N suggests that a source of N from legume residues was not sufficient for a succeeding corn crop. There was significantly more N (P

• Korean Journal of Weed Science
• /
• v.13 no.4
• /
• pp.234-249
• /
• 1993

Herbicide is an essential agricultural chemical in the modern agriculture. Due to its bioactivity, however, risk of herbicide use against non-target organisms should be seriously considered. Among the unfavorable aspects given by herbicide, the residue is the most important because herbicide residue in soil and agricultural product is closely related to human safety. The residue in soil and crop is dependent on conditions of soil, weather, herbicide use and crop cultivation, etc. In general, the residue in soil or agricultural product in Korea is known to be not serious at this moment, except for some problems like carry-over effect on succeeding crops. To secure safety of herbicide use for the health, soil ecology and other environment, researches on herbicide residue including monitoring survey should be done more frequently and extensively. Safety guide for herbicide usage should be kept by farmers and development of long toxic herbicide should be accelerated.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.161-161
• /
• 2017

Seed endophytes are very remarkable groups of bacteria for their unique abilities of being vertically transmitted and conserved. As plants attain hybrid vigor and heterosis in the process of crossbreeding, this might also lead to the changes in the community structure and diversity of plant endophytes in the hybrid plants ultimately affecting the endophytes of the seeds. It would be interesting to characterize how seed endophyte composition change over time. The objective of this study is to gain insights into the influence of natural crossbreeding and parental lineage in the seed bacterial endophytic communities of two pure inbred lines exploring contributions of the two most important sources of plant endophytes - colonization from external sources and vertical transmission via seeds. Total genomic DNA was isolated from rice seeds and bacterial DNA was selectively amplified by PCR. The diversity of endophytic bacteria was studied through Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis. Diversity between the original parents and the pure inbred line may show significant differences in terms of richness, evenness and diversity indices. Heat maps reveal astonishing contributions of both or either parents (IR29 ${\times}$ Pokkali and AT401 ${\times}$ IR31868) in the shaping of the bacterial seed endophytes of the hybrid, FL478 and IC32, respectively. Most of the T-RFs of the subsequent pure inbred line could be traced to any or both of the parents. Comparison of common and genotype-specific T-RFs of parents and their offspring reveals that majority of the T-RFs are shared suggesting higher transmission of bacterial communities common to both parents. The parents influence the bacterial community of their offspring. Unique T-RFs of the offspring also suggest external sources of colonization particularly as the seeds are cultivated in different ecogeographical locations. This study showed that host parental lines contributed greatly in the shaping of bacterial seed endophytes of their offspring. It also revealed transmission and potential conservation of core seed bacterial endophytes that generally become the dominant microbiota in the succeeding generations of plant hosts.

• Korean Journal of Weed Science
• /
• v.12 no.3
• /
• pp.261-270
• /
• 1992

Many herbicides that are applied at the soil before weed emergence inhibit plant growth soon after weed germination occurs. Plant growth has been known as an irreversible increase in size as a result of the processes of cell divison and cell enlargement. Herbicides can influence primary growth in which most new plant tissues emerges from meristmatic region by affecting either or both of these processes. Herbicides which have sites of action during interphase($G_1$, S, $G_2$) of cell cycle and cause a subsequent reduction in the observed frequency of mitotic figures can be classified as an inhibitor of mitotic entry. Those herbicides that affect the mitotic sequence(mitosis) by influencing the development of the spindle apparatus or by influencing new cell plate formation should be classified as causing disruption of the mitotic sequence. Sulfonylureas, imidazolinones, chloroacetamides and some others inhibit plant growth by inhibiting the entry of cell into mitosis. The carbamate herbicides asulam, carbetamide, chlorpropham and propham etc. reported to disrupt the mitotic sequence, especially affecting on spindle function, and the dinitroaniline herbicides trifluralin, nitralin, pendimethalin, dinitramine and oryzalin etc. reported to disrupt the mitotic sequence, particularly causing disappearence of microtubles from treated cells due to inhibition of polymerization process. An inhibition of cell enlargement can be made by membrane demage, metabolic changes within cells, or changes in processes necessary for cell yielding. Several herbicides such as diallate, triallate, alachlor, metolachlor and EPTC etc. reported to inhibit cell enlargement, while 2, 4-D has been known to disrupt cell enlargement. One potential danger inherent in the use of soil acting herbicides is that build-up of residues could occur from year to year. In practice, the sort of build-up that would be disastrous is unikely to occur for substances applied at the correct soil concentration. Crop injury caused by soil applied herbicides can be minimized by (1) following the guidance of safe use of herbicides, particularly correct dose at correct time in right crop, (2) by use of safeners which protect crops against injury without protecting any weed ; interactions between herbicides and safeners(antagonists) at target sites do occur probably from the following mechanisms (1) competition for binding site, (2) circumvention of the target site, and (3) compensation of target site, and another mechanism of safener action can be explained by enhancement of glutathione and glutathione related enzyme activity as shown in the protection of rice from pretilachlor injury by safener fenclorim, (3) development of herbicide resistant crops ; development of herbicide-resistant weed biotypes can be explained by either gene pool theory or selection theory which are two most accepted explanations, and on this basis it is likely to develop herbicide-resistant crops of commercial use. Carry-over problems do occur following repeated use of the same herbicide in an extended period of monocropping, and by errors in initial application which lead to accidental and irregular overdosing, and by climatic influence on rates of loss. These problems are usually related to the marked sensitivity of the particular crops to the specific herbicide residues, e.g. wheat/pronamide, barley/napropamid, sugarbeet/ chlorsulfuron, quinclorac/tomato. Relatively-short-residual product, succeeding culture of insensitive crop to specific herbicide, and greater reliance on postemergence herbicide treatments should be alternatives for farmer practices to prevent these problems.

• Korean Journal of Organic Agriculture
• /
• v.9 no.2
• /
• pp.101-115
• /
• 2001

Nitrogen applied as fertilizer for crop production is partly absorbed by plant , and the remaining nitrogen in soil might be leached out through complicated processes to the subsoil layer Especially, NO$_3$-N in leachate causes environmental pollution. The purpose of this study was focused on understanding of uptake of nutrients by plants, the behaviors of nutrients in soil and the possibility of leaching loss when nitrogen fertilizer and completely decomposed compost were applied. Lysimeters(Volume 0.15㎥, Diameter 62cm, Height 62.8cm) were installed for collecting leachate in the Jeju volcanic ash soils. Lysimeter study consisted of thirteen treatments : fallow, fallow with weeding, cropping without fertilizer and compost, three N fertilizer soil surface applications(16, 32, 64kg/10a), three N fertilizer and compost soil surface applications(16+800, 32+1600, 64+32kg/10a), two water dissolved N fertilizer applications(16, 32kg/10a), and low and high plant densities. N fertilizer was applied as urea. The growth of com(preceding crop) and potatoes(succeeding crop) and leaching loss were determined during the experimental period. The results obtained were summarized as follows ; With Increased N, pH of leachate tended to decrease and NO$_3$-N concentration of leachate increased. NO$_3$-N leaching loss was remarkably greater in soil from the bare plot without fertilization and the weed control than from plots with medium N rate and was least in the cropping plot without fertilization. NO$_3$-N concentration in leachates from the water dissolved N fertilizer application plots was 64% of that from the soil surface application plots. The concentration of Ca and K ions and the leaching loss of these ions were least from the cropping plot without fertilization and were greatest from bare plots(T1 and T2) without fertilization. The proportion of leaching and residual N in soil increased as N rate increased indicting that higher N rates increase the possibility of N leaching to subsoil layer The proportion of N leaching losses was lower at the low N rate and the high plant density. In future, fertilization prescription which can maximize fertilizer use efficiency and minimize the pollution of ground water will be needed for conserving the environments.