• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.285-299
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• 1987

Timing and placement of fertilizer applications are two managerial means to improve the fertilizer use efficiency. The relative importance of these two means is determined by the application rate. With the realistic rate of N application recommended to the small farmers in the tropics, at present and in the near future, basal application in right manner, seems to be more important than split application at different times. In wetland rice soils, deep placement by whatever available means is desirable. But in the situations where perfect deep placement is very difficult to implement, the whole-layer application may be worth trying, until better methods become available. In rainfed uplands, N fertilizer application plans should be contingent upon the amount and distribution of rainfall: apply a less risky rate as subsurface banding near the crop rows to start with; then, depending upon the rainfall prospects in the season, apply or omit the additional dose. Because the patterns of crop response to N fertilizer can be significantly different between the research farms and farmers' fields, it seems imperative to have information on the patterns of crop response to N under farmers' management conditions, for the development of realistic fertilizer application recommendations. To enable the farmers to adopt improved fertilizer application technologies, it is essential to develop and make available to farmers convenient fertilizer applicators. Past experience with the improved fertilizer use technologies indicates that, in the long run, the development of fertilizers that are not only effective and convenient for farmers to use but also easy to produce without major modifications of existing fertilizer production systems is the ultimate solution to the problem of low N fertilizer use efficiency.

• Korean Journal of Soil Science and Fertilizer
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• v.14 no.4
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• pp.215-218
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• 1982

The fertilizer efficiency of the compound fertilizers with different NPK Compositions were compared with that of simple fertilizers in the view of the yield differences of Jungweon Cheongyong Capsicum grossum of Hot pepper. The results were summarized as follows: 1. The yields of ripened red peppers of the compound fertilizer plot were higher than that of the simple fertilizer plot showing no statistical differences between the fertilizers. 2. No differences in the nutrient composition of the plant leaves were found between the treatments, thus the yield was not correlated with the nutrient composition. 3. In the soil where the compound fertilizers were used, the available phosphate content after the harvest increased but other nutrient contents were unchanged.

• Asian Journal of Turfgrass Science
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• v.11 no.2
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• pp.97-104
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• 1997

The objective of this study was to observe the differences in growth of creeping bentgrass turf to 'polymer coated urea fertilizer' and 'uncoated urea fertilizer', and to analyze durability of fertilizer effect with the 'polymer coated urea'. The experiment was initiated on June 3, 1996, at the Iowa State University Horticulture Research Station, north of Ames, Iowa. The experiment was conducted on an area of 'Penneagle' Creeping bentgrass(Agrostis palustris) maintained at fair-'way mowing height (1.3cm). The study was repeated at the same arrangement beginning on July 25, 1996. Visual quality data, clipping fresh and dry weight, and nitrogen(N) content in the clippings were taken weekly. Quality of the turf increased with increasing N rate. While quality ratings were higher for turf receiving polymer coated urea than for turf receiving uncoated urea at several times following treatment, but not significant. Fresh and dry clipping weights were quite variable during the trial. Visual quality rating and clipping yields improved with increasing rates of N but these differences were not statically significant between polymer coated and uncoated urea treatment. The durability of fertilizer efficiency in polymer coated urea was not last longer compare with uncoated urea from two weeks after treatment. Higher rates of N application increased the concentration of N in tissue but no significant differences between turf plots receiving polymer coated and uncoated urea. Key words: Polymer coated urea, Creeping bentgrass, Fertilizer, Turfgrass.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.174-182
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• 1985

In order to obtain information necessary for attaining maximum yield of rice by increasing nitrogen efficiency, effects of top dressing of nitrogen fertilizer at the later part of growing season were investigated and results obtained are summurized as follows: 1. The increased application of nitrogen fertilizer was very effective in increasing leaf areas and net assimilation rate of rice plants. The spikelets number per hill was also increased due to heavy nitrogen fertilizer. 2. The concentrated top dressing at the later part of plant growth apparently increased the crop growth rate at the reproduction stage and ripening stage of rice, respectively. The nitrogen efficiency was greatly improved by the concentrated top nitrogen dressing through the increase of effective tiller number and the improvement of production organ to non productive organ ratio. 3. The concentrated top nitrogen dressing at the later growing season was considered to be one of the most effective methods of fertilizer applications as well as cultivation of fertilizer resistant varieties for the high yield of rice and improving soil fertility.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.4
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• pp.199-217
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• 1975

For the establishment of efficient method of potassium topdressing on rice the optimum time and amount were investigated and discussed on the basis of available data from nutriophysiological studies, soil characteristics and fertilizer trials in fields. The followings were pointed out. 1. According to yield rice plants require more potassium around heading under water culture. 2. Potassium involves in harvest index, filled grain ratio, grain weight and number of spikelets per panicle. 3. Potassium is lost after heading in most fields in spite of highest requirement during this period. 4. The higher $K_2O/N$ ratio in straw at harvest is, the higher the yield. 5. Relatively low efficiency of potassium fertilizer under the field condition may be due to improper application method rather than natural supply from soil and irrigation water. 6. Appropriate topdressing time appears at in effective tillering stage for the prevention of nitrogen excess and at 15 to 20 days after transplanting, ear formation stage and 5 days after heading for the prevention of soil reduction damage. Two times of topdressing for clayey soil and three times for sandy soil seems reasonable in practice together with nitrogen topdressing, 7. The reasonable ratio basal to topdressing of potassium fertlizer seems to be 2/3 and $N/K_2O$ ratio of fertilization for ear formation stage appeared also as 2/3.

• Journal of Korean Society for Quality Management
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• v.49 no.2
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• pp.213-231
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• 2021

Purpose: This study intends to provide decision-making information to improve efficiency by analyzing the management efficiency of smart greenhouse business entities and identifying factors that affect the efficiency based on input and output. Methods: The subjects of analysis were business entities for cultivating strawberries in smart greenhouses in Jeolla region (northern and southern Jeolla provinces), and the analysis focused on the management performance of the 2019-2020 crop period (year). Data Envelopment Analysis(DEA) was applied as an analysis method for efficiency analysis, Quantile Regression(QR) analysis was applied as a factor affecting the efficiency. Results: The reason for the efficiency gap between business entities was that there were many business entities that did not minimize the input cost at the current level of output, and the area where the variance among business entities was large was the fixed cost per 10a. In the results of the affecting factor analysis, it was found that the seed-seedlings cost, fertilizer cost, other material cost, and employment and labor cost had a negative (-) effect on the efficiency, and that the repair and maintenance cost had a positive (+) effect. Conclusion: Therefore, to achieve the efficiency of scale, it is necessary to reduce the input scale to an appropriate level. In the case of business entities with low efficiency by quartile, the seed-seedlings, fertilizer, and other material costs reduce expenditures, and repair maintenance costs can improve efficiency by increasing expenditures.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.208-214
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• 1985

An attempt to evaluate yield response and efficiency of N fertilizer was made with the data obtained from various rice cultivars during 1978 to 1983. 1. The optimum rate of N fertilizer for maximum yield varied from 13.9 to 28.0 kg/10a with rice varieties. 2. The cultivars with high optimum N levels were high in N content (straw) and N uptake (straw+grain) at harvesting stage, but low in production efficiency and use efficiency of N. 3. The yield increment at the optimum rates of N in comparison with no N application among the rice varieties were 29-101%. 4. The cultivars with hish yield increment at optimum rate were high in the N content (straw+grain), and production efficiency at harvesting stage.

• Nuclear Engineering and Technology
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• v.10 no.4
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• pp.215-222
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• 1978

Using tracer technique of $^{65}Zn$, a field experiment has been carried out to evaluate the efficiency of zinc fertilizer by rice plant grown under flooded conditions. The treatments include zinc slufate mixed throughout the soil with and without organic matter, combined urea-zinc fertilizer (N: 37.7%, Zn: 3.1%), and surface application at transplaning and two weeks after transplanting at the rate of 5kg Zn/ha respectively. Other treatments were zinc sulfate mixed throughout the soil at the rate of 10 kg and 20 kg Zn/ha respectively. Root dipping in 2 % ZnO suspension, only organic matter added, and control were also included. There was not much difference in rough grain yield between zinc levels and different application methods, but the highest yield was obtained from the treatment of the root dipping in 2% ZnO suspension. Among the 5kg Zn/ha treatments, the highest total zinc yield was observed from the zinc mixed throughout the soil. The organic matter treatment seemed to reduce the zinc fertilizer efficiency. In case of the zinc fertilizer levels, 5kg Zn/ha mixed throughout the soil showed the highest zinc fertilizer efficiency as compared with 10kg and 20kg Zn/ha treatments.

• Korean Journal of Organic Agriculture
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• v.26 no.4
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• pp.731-743
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• 2018

This study was conducted to evaluate the effects of green manures and complemental fertilization with oil cake or liquid fertilizer on growth and nitrogen use efficiency of Chinese cabbage cultivated in organi systems. Field experiments were carried out at the National Institute of Agricultural Science in Suwon, South Korea from 2012 to 2014. Two green manure crops, Crotalaria and Hairy vetch, was cultivated in summer and in winter, respectively. The application methods of the green manure consisted of three tillage systems (overall tillage, partial tillage and no tillage). Oil cake and liquid fertilizer were used as complemental fertilizer. The results showed that when used as covering material in the upland soil without tillage, green manure fertilization was more effective in increasing growth and yield of Chinese cabbage than when incorporated into soil. It was possible to grow and harvest Chinese cabbage in the spring season by the application of hairy vetch as winter green manure. The higher yield of Chinese cabbage with green manure application was caused by the lower incidence rate of soft rot and tip-burn. The yield of the Chines cabbage that received green manure applications over two consecutive seasons followed by the supplemental fertilization with oil cake was similar to that of the conventional chemical fertilization. Following a single season green manure application in summer, however, the yield of cabbage was only about 70% of the conventional treatment. Green manure cultivation with additional liquid fertilization produced a yield similar to the conventional fertilization treatment, soil inorganic nitrogen concentration remained stable and the nitrogen use efficiency increased in the green manure applied soil. In conclusion, the organic cultivation of Chinese cabbage in the autumn season could be outperformed in the upland soil receiving two seasons (winter and summer) of green manure fertilization followed by the supplemental fertilization with liquid fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.594-597
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• 2014

Crop yields depend on the limiting factor of crop growth; Liebig law of minimum. Identifying the kind and the necessary amount of the limiting factor is essential to increase crop yield. Although nitrogen is the most essential nutrient, N application does not always bring about yield increases when other elements are limiting in rice cultivation. Two experiments were compared to elucidate the effect of soil testing on rice yield response to N level. The one was an experiment about yield response of 3 rice cultivars to 7 levels of N application, which was conducted from 2003 to 2004 in 25 farmer's fields without ameliorating soil conditions by soil testing and the other was a demonstration experiment on N fertilizer recommendation equation by 0, 0.5, 1.0, and 1.5 times of N recommended level in 5 soil types from 30 fields after ameliorating soil conditions by soil testing. The N response patterns of the experiments conducted without soil testing showed a Mitscherlich pattern in some cultivars and soil types, but did not in the others. The N response patterns of the demonstration experiment showed a Mitscherlich pattern in all soil types. Because these results indicated that N was the minimum nutrient in the demonstration experiment by ameliorating soil conditions with soil testing, but not in the other experiment without soil testing, the supply of minimum nutrients by soil testing could increase the efficiency of N-fertilization.