• International Journal of Industrial Entomology and Biomaterials
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• v.25 no.1
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• pp.123-127
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• 2012

An experiment was carried out to boost the production of tasar crops through application of secondary nutrients. Different combinations of secondary nutrients were prepared and its effect was studied on the yield and quality of leaves of tasar food plant Terminalia tomentosa W & A with 2.4 m ${\times}$ 2.4 m spacing and cocoon characters of tasar silkworm Antheraea mylitta Drury reared on them. Among different combinations of secondary nutrients, foliar application of magnesium sulphate (2%, w/v) and basal application of 3 quintal/ha of calcium carbonate (secondary nutrient combination SM5) was found to be the best in crop improvement. It improves the quantity and quality of leaves as well as the commercial characters of cocoons. As a result, silk production improves. Under this combination, leaf yield increased by 26.55% in comparison to control. Average increase in moisture, total mineral, crude protein and total carbohydrate was 3.26%, 20.84%, 15.39% and 17.85% respectively as compared with control. Further, bio assay studies revealed that average larval weight, E.R.R., cocoon weight, shell weight and silk ratio percent increased by 11.25%, 25.71%, 20.05%, 35.14% and 12.17% respectively over control which indicates that secondary nutrient combination $SM_5$ has significant role in improving the production of tasar crops.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.363-369
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• 2009

This experiment was conducted to find out the effect of nutrient solution composition on the growth of cucumber plants and the changes in macro-elements in nutrient solutions in recirculating hydroponic systems. Cucumber plants (Cucumis sativus L. cv. Joeun Baegdadagi) were grown in closed perlite cultivation systems supplied with different nutrient solutions developed by NHRS (National Horticultural Research Station in Japan), Yamasaki, PBG (Proefstation voor Bloemisterij en Glasgroente), and NIHHS (National Institute of Horticultural and Herbal Science in Korea). The concentrations of $NO_{3^-}N$, $Ca^{2+}$, $Mg^{2+}$, and $SO_{4^-}S$ in the recycled nutrient solutions increased but that of $NH_{4^-}N$ decreased gradually in all the treatments. The $PO_{4^-}P$ and $K^+$ concentrations were continuously reduced from the beginning of the harvest to the harvest peak period. There were no significant differences in the concentrations of $NO_{3^-}N$, $NH_{4^-}N$, and $Ca^{2+}$ in the recirculated nutrient solutions among four treatments, while the concentrations of $PO_{4^-}P$ and $K^+$ were lowest and those of $Mg^{2+}$ and $SO_{4^-}S$ were highest in the treatment of Yamasaki's nutrient solution. All growth-related parameters of cucumber plants except for leaf number were not significantly affected by the nutrient solution compositions. Due to its low concentrations of $PO_{4^-}P$ and $K^+$ in the recycled nutrient solution, however, the number and yield of cucumber fruits were lowest in the treatment of Yamasaki's nutrient solution.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.189-196
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• 2011

The objective of this study was to investigate the effects of light intensity and electrical conductivity (EC) of nutrient solution during short day treatment in an ebb and flow systems on the growth and nutrient uptake of potted Kalanchoe blossfeldiana 'Rako' and the nutrient accumulation of growing medium. Nutrient concentrations in the growing medium were also analyzed to investigate the accumulation rates of macro-nutrients such as T-N, P, K, Ca, and Mg, respectively. To achieve the objectives, plants were fed with a nutrient solution with 1.2, 1.8, or $2.4dS{\cdot}m^{-1}$ under three daily photosynthetic photon flux (PPF) of 4.26, 5.51, or $9.75mol{\cdot}m^{-2}{\cdot}d^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the crop growth. The elevation of PPFs resulted in the increase of plant growth. For each light condition, plant growth, such as dry and fresh weight and leaf area, was the highest when the electrical conductivity of nutrient solution was controlled to $2.4dS{\cdot}m^{-1}$. However, growth was acceptable in the EC ranges from 1.8 to $2.4dS{\cdot}m^{-1}$. Both light intensity and EC of nutrient solution significantly influenced the uptake of nutrients in the solution tanks and the accumulation of nutrients in the growing medium. As the EC of nutrient solution was elevated, the absorption rates of $NO_3^-$, $PO_4^{-3}$, $K^+$, and $Mg^{2+}$ by crops and accumulation of those in growing medium increased, but the light intensity did not significantly influence the absorption rates. Based on the above results, the regression models were suggested for anticipating the macro-nutrient accumulations in growing medium.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.83-89
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• 2010

We investigated the growth of cucumber plants, the uptake and use of mineral nutrients, such as $NO_3$-N, $NH_4$-N, $K^+$, $Ca^{+}^{+}$, $Mg^{+}^{+}$ and $Na^+$, absorbed from media solution, and the synthesis and distribution of soluble sugars under nutrient-deficient condition. Difference in plant growth revealed after 20 days of treatment. Nitrate uptake in nutrient-deficient condition was significantly reduced compared with nutrient-normal treatment, and its distribution was primarily in petioles, stem, roots and less in leaves. In contrast, ammonium content was markedly predominated in fast growing organs, and it was significantly different in growing leaves, expanded leaves, and roots under similar growth conditions. $K^+$, lack by deficient nutrient condition, was found in growing leaves. The $Ca^{+}^{+}$ content did not show significant difference between treatments and a substantial portion of $Ca^{+}^{+}$ remained in petioles. The $Mg^{+}^{+}$ content was significantly higher in the leaves of nutrient-normal condition compared with nutrient-deficient condition while significantly lower in stem and roots. The behavior of $Na^+$ in plant was similar to $K^+$ although its content was relatively little. The highest $CO_2$ assimilation was observed in fully expanded leaves of nutrient-normal condition, which was 1.7 times higher compared with nutrient-deficient condition. The instantaneous water use efficiency (A/E) and the A/gsratio, which is an index of leaf intrinsic water use efficiency for individual leaves, was 1.2 and 1.1 times higher, respectively. The total soluble sugar (TSS) contents were highest in leaves followed by petioles, stems and roots, and in younger leaves. The growing leaves contained about 7,200 mg $kg^{-1}$ of TSS in nutrient-normal condition whereas the TSS contents in nutrient-deficient condition were not significantly different between leaves. The $Mg^{+}^{+}$ and $NH_4$- N were positively correlated with the TSS whereas $NO_3$ - N was negatively correlated.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.23-29
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• 2018

The litter production, the nutrient concentration of each component of litterfall, and the amounts of nutrient into the forest floor via litterfall were assessed for 5 years from January 2009 through December 2013 in a Pinus densiflora forest in Mt. Worak National Park. The average amounts of leaf litter, branch and bark, reproductive organs(flowers and cones), and miscellaneous categories for 5 years were $1.940{\pm}0.21$, $0.505{\pm}0.15$, $0.259{\pm}0.09$, and $0.737{\pm}0.14t\;ha^{-1}yr^{-1}$, respectively. The average percentage of leaf litter, branch and bark, reproductive organs and miscellaneous categories for 5 years were 56.4, 14.7, 7.5, and 21.4%, respectively. The amounts of total litterfall in 2009, 2010, 2011, 2012, and 2013 were 2.810, 3.796, 3.268, 3.284, and $4.045ton\;ha^{-1}yr^{-1}$, respectively. The average amounts of litterfall for 5 years were $3.441{\pm}0.4ton\;ha^{-1}yr^{-1}$. The average amounts of N, P, K, Ca, and Mg returned to the forest floor via litterfall for 5 years in this Pinus densiflora forest were $22.73{\pm}4.92$, $1.05{\pm}0.42$, $4.26{\pm}1.69$, $8.48{\pm}4.62$, and $2.42{\pm}1.01kg\;ha^{-1}yr^{-1}$, respectively.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.314-321
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• 2007

This study was conducted to select leaf vegetables suitable for cultivation in apartment verandas and simple and easy fertigation method for home gardening. In order to develop the convenient fertigation method, hydroponics, wick irrigation, and overhead irrigation methods were compared. For the wick irrigation, two types of nutrient sources were used; one was slow release fertilizers mixed with medium and the other one was nutrient solution filled in container located under pots. The growth of leafy lettuce, leaf mustard, and leaf beet was better in both of the wick irrigation methods rather than in overhead irrigation and hydroponics. The wick irrigation method is very easy, so that it is expected to bring a good result from the cultivating and managing point of view, if it brings with commercialized system along with slow release fertilizer. As a result of investigation of environment such as temperature, relative humidity, and irradiance level in apartment verandas in autumn the highest irradiance level during a day was just 48% and 35% in verandas facing south and feeing southeast, respectively, comparing to that in greenhouse. The light environment was investigated as a limiting factor for vegetable growing in verandas. Therefore, to select the vegetables showing good growth under low irradiance environment, nine leaf vegetables such as romaine lettuce, lent lettuce, head lettuce, endive, pak-choi, leaf mustard, garland chrysanthemum, leaf beet, and Chinese chive were grown under 0%, 50%, 70%, 90% shading. Among them, Chinese chive showed the best growth under low irradiance levels. Endive showed line growth reduction according to shading degree, however, even under 90% shading condition, it showed good growth. And then leafy lettuce, garland chrysanthemum, and pak-choi followed. Therefore, these results will be of help in selecting vegetables for veranda gardening with different light levels.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.3
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• pp.163-175
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• 1974

Effects on yields, yield components and nutrient content of potassium depression for two or three weeks at various growth stages were investigated in rice (var. Jinheung) under sand culture system.(K 40 ppm 1973) 1. Analysis of variance showed significant difference among treatments of both two-week (at p=0.01) and three-week depression (at p=0.05) in yield. 2. Most sensitive stage to potassium depression on yield appeared two weeks until heading (42% yield decrease) and sensitivity decreased the growth stage is apart from heading either before or after. During 30 days after transplanting two-week potassium depression increased yield, but three-week depression decreased yield. Until about 30 days after heading depression caused poor yield. 3. Root potassium involves in harvest index, filled grain ratio and grain weight with significant correlation and considerably in spikelet per panicle while potassium in leaf sheath+culm involves considerably in spikelet per panicle and panicle per hill. Relative total dry matter weight was significantly correlated with panicle per hill, spikelet per panicle and K or K/Ca+Mg only in leaf sheath+culm. The indications are that root potassium contributes for building sink and efficiency of structure while potassium in leaf sheat+culm primarily for building source, productive structure. 4. Relative yield was significantly correlated with potassium content in root and leaf sheath+culm and with K/Ca+Mg and its ratio before and after depression in root indicating that potassium depression occurs greatly in root and that K/Ca+Mg might have more important role than K content alone under depression. 5. Optimum level of $K_2O$ appears around 3% in leaf blade. 4% in leaf sheath+culm and 1% in root under the assumption that below these level the same content has the same role in relation to yield during growth. The K/Ca+Mg appeares to be 2.5 in root and should not decrease throughout the growth stages. 6. The increase of sodium content in plant by K depression was highest, especially in leaf sheath during the most insensitive period to K depression suggesting that insensitivity may be attributed to partial replacement of Na for K. Partial replacement seems very little in sensitive stage (later stage) and sensitive organ (root).

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.558-562
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• 2014

Cover cropping and liquid manure application are considered as effective ways to replace the use of chemical fertilizer in orchard. This study was conducted to investigate the effect of cover crop species and liquid manure application rate on green manure production, leaf mineral content, fruit quality and soil chemical properties in pear orchard. The treatments include rye and hairy vetch as cover crops, two liquid manure application levels based on N and $K_2O$ requirement on each cover crop species, and chemical fertilizer as control. Green manure production was higher in hairy vetch than in rye. K content of pear leaves and soil exchangeable K content increased in N based liquid manure application treatments. The yield was higher in rye + liquid manure and fertilizer treatments, and fruit quality was not different between the treatments. Taking all of these into account, rye + $K_2O$ requirement-based liquid manure application is recommended in pear orchard for not only sufficient nutrient supply but also prevention of any problem related with soil $K_2O$ accumulation in pear orchard in long-term perspective.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.10a
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• pp.15-20
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• 2005

Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by analytical electron microscopy and atomic force microscopy. A blast-susceptible cultivar, Jinmi, and partially resistant cultivars, Hwaseong and Suwon345, were grown under a hydroponic culture system with modified Yoshida's nutrient solution. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamella, and Intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface with relatively small deposition on stomatal guard cells in silicon-treated plants. Force-distance curve measurements revealed relative hardness and smaller adhesion force in silicon-treated plants (18.65 uN) than control plants (28.39 uN). Moreover, force modulation microscopy showed higher mean height values of elastic Images In silicon-treated plants(1.26 V) than in control plants (0.44 V), implying the increased leaf hardness by silicon treatment. These results strongly suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.683-688
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• 2015

Nowadays, sustainable and environment-friendly agriculture has become an important issue all around the world, and repeated applications of mineral and/or organic fertilizer will probably affect mineral nutrient dynamics in soil in the long term but only a limited number of observations are available. This study was carried out to investigate whether there is any influence of different fertilizer management for red pepper (Capsicum annuum L.) cultivation on soil physicochemical properties, leaf mineral content, yield and fruit quality in the aspect of long-term practice in open field condition. NPK, NPK+compost, compost only, and unfertilized control plot were included in the treatments. The application of chemical fertilizer and/or compost repeated annually for 17 years from 1994 to 2011. Soil organic matter content was higher in compost treatments than in no-manure treatments. Available phosphate and the yield of red pepper were highest in NPK+compost treatment followed by NPK (chemical fertilizer), compost, and control. The results indicate that in the long term, nitrogen supply is still needed for increasing red pepper yield, but reduction in the use of chemical fertilizer could be also possible with the proper application of compost.