• Korean Journal of Environmental Agriculture
• /
• v.29 no.1
• /
• pp.12-19
• /
• 2010

Optimum nitrogen fertigation level by soil testing was determined on the growth and yield of eleven-year-old 'Campbell Early' (Vitis labrusca L.) grapevine in a sandy loam soil from 2005 to 2007. Fifty percent of the annual application of the nitrogen rate (195 kg/ha/yr) was top-dressed as basal fertilizer in all treatments, and the remainders were drip-irrigated with fertigation rate at 25 (12.5% of total N, N 1/4 level of the remainder), 50 (25% of total N, N 1/2 level), and 100 mg/L (50% of total N, N 1 level) in intervals of twice (2.1 mm/times) a week for 12 weeks, and the effect of N drip fertigation was compared to control which the N remainder was applied with surface application as an additional fertilizer. The results showed that chlorophyll content reading in SPAD value and N contents of leaves increased as nitrogen fertigation level increased. Also observed was the growth of the internode and stem diameter of shoots which were longest at N 1/2 level among the treatments conducted both in 2005 and 2006. It was also noted that yield of the fruit was different every year, where average yield for three years was recorded highest in N 1/4 level, and lowest in N 1 level compared to control(surface application). Soluble solid content and titratable acidity of fruit juice were also not significant during the treatments, the maturation of fruits tended to be retarded in N 1 level. The study proved that N 1/4 (N 25 mg/L) levels of fertigation based on soil testing was most efficient in obtaining optimum yield and also, fertigation of grapevine at open field condition reduces the use of nitrogen fertilizer.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.6
• /
• pp.388-395
• /
• 2004

This study was carried out to determine the application rate of pig slurry for red pepper. Field experiment was designed with non-fertilizer, chemical fertilizer recommended by soil testing (CFRST) and pig slurry treatments. In pig slurry (PS) plots, pig slurry was applied as basal fertilizer with different equivalents to nitrogen of chemical fertilizer plot (60%: PS60, 80%: PS80, 100%: PS100, 120%: PS120) and chemical fertilizer was top-dressed additionally. Soil organic matter contents after 50 day of planting and after experiment in the plots treated with PS were higher than that of CFRST plot, whereas content of $NO_3-N$ of CFRST plot was higher than that of PS plot. Growth of red pepper were lowest in the non-fertilizer plot. Plant lengths of red pepper at 50 day after planting were similar among the different treatments, plant lengths of red pepper of PS100, PS120 and CFRST at 100 day after planting were higher than those of the PS60 and PS80 plots. But Main stem and stem diameter of red pepper were not different among the treatments. Uptake rate of N, P and K by red pepper plant were 27-44, 9-16 and 41-68% for total N, $P_2O_5$ and $K_2O$, respectively. Utilization of applied fertilizer ingredient by red pepper plant were in the order of PS80> PS60> FRST> PS100> PS120. Yield of red pepper tends to increase by 3% in the PS100 compared with the CFRST, but there was not significant difference between PS120 and CFRST. Chemical component of run-off collected from the furrow of the red pepper field was not different among the treatments. Greenhouse gases ($CH_4$ and $N_2O$) emission of non-fertilizer, PS100 and CFRST during the whole red pepper growth period were 4.0, 4.8 and $5.9kg\;CH_4\;ha^{-1}$, and 0.74, 6.68 and $8.38kg\;N_2O\;ha^{-1}$. Emission of $CH_4$ and $N_2O$ in PS100 was higher than those of CFRST by 23% and 26%, respectively. In this connection, to be used the pig slurry for red pepper, it is required that pig slurry must be decomposed for six months or more. Consequently, pig slurry equivalent to nitrogen of basal fertilizer of CFRST with additional top dressing of chemical fertilizer is recommend as an optimum application rate of pig slurry for red pepper.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.6
• /
• pp.479-483
• /
• 2003

Knowledge of N accumulation during the vegetative growth stage of rice (Oryza sativa L.) is useful for determining the need for topdressing fertilizer N at panicle initiation and booting stage. The chlorophyll content showing SPAD threshold values generated by a simple and portable diagnostic instrument, chlorophyll meter, enables implement the measures of greenness and/or relative chlorophyll contents of leaves. Two-year field experiment was conducted to evaluate the possible application of the chlorophyll meter for N diagnosis in transplanted paddy rice. The chlorophyll meter threshold values (SPAD reading) were taken from uppermost fully expanded leaves at 10days interval from 10 days after transplanting. SPAD readings and N contents of rice leaf blade were closely related at the maximum tillering stage. SPAD readings during growth period showed M-shaped distribution, sharply finished to drop at 20 days after heading date. As N fertilizer increased, the SPAD readings increased. The SPAD readings showed more critical and clear difference in immature paddy field than in ordinary paddy field, where the former soil showed higher response to N fertilizer topdressed. Based on the PAD readings for obtaining an optimum sink size bearing the maximum grain yield, N fertilizer to be dressed at the panicle initiation stage is to be adjusted within the SPA$\times$tillers value range 888 in ordinary paddy, and 800 in immature paddy vice. Among the cultivars tested, Huckhyangbyeo, Jinpumbyeo, Ansungbyeo, Sobibyeo, Manpungbyeo, Sangmibyeo, Jinbongbyeo, showed high SPAD values, whereas the cultivars, Nonghobyeo, Saechuchungbyeo, Hwabongbyeo, Mananbyeo, did low values and others intermediate SPAD threshhold values.

• Korean Journal of Soil Science and Fertilizer
• /
• v.11 no.2
• /
• pp.81-87
• /
• 1979

In order to observe the lasting effect of NK-compound mineral fertilizer and organic compound fertilizer including Myweon organic liquid fertilizer, a pot experiment was conducted with rice (Oriza Sativa) variety: Nong Back. These fertilizers were applied as basal and the same amount of urea form of nitrogen was top dressed about a month after transplanting, July seventh, 1977. Results obtained are as follows; 1. The lasting effect of various fertilizers were laid in following decreasing order; Myweon liquid < Organic compound fertilizer (Myweon coop. made) > NK-compound fertilizer (Chosun coop. made) Single fertilizer. It was considered that organic matter served as microbial feed and lead a temporary fixation of available plant nutrients in the soil, and the reduced surface area of the compound fertilizers slowed down the availability of the fertilizers. 2. The fertilizer showing greater lasting effect produced more panicles per hill and less grains per panicle than the fertilizers showing less lasting effect, and brought low maturity, which resulted in low paddy yield the paddy producing efficiency of nitrogen absorbed by straw was also low in the former fertilizers. Such advanced effect of the former fertilizer was considered to be related with the variety of early maturity and unseasonable topdressing of fertilizer which made at the maximum tillering stage. 3. For the production of Japonica type paddy with heavy fertilization which may required to depress the early growth a little and promote the late growth, it might be necessary to develop slow releasing fertilizers such as single fertilizer formulated to a large grains or compound fertilizer containing organic matter. 4. If the nitrogen content of paddy, Nong Back, far excess 0.64 or 0.65% and reaches 0.68% or above, the yield of the variety seemed to be decreased remarkbly through the low maturity rate and thousand grain weight.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.2
• /
• pp.132-137
• /
• 2011

BACKGROUND: This experiment was carried out to evaluate the effect of potassium fertigation on the growth and yield of fourteen years-old 'Campbell Early' grapevine (Vitis labrusca L.) on a sandy loam soil. METHODS AND RESULTS: Potassium application (125 kg/ha/yr) was top-dressed as 30% of annual potassium application in all treatments and the remainders were drip-irrigated with 0 (0% of total K, K0 level of the remainder), 25 (17.5% of total K, K1/4 level of the remainder), 50 (35% of total K, K1/2 level), and 100mg/L (70% of total K, K1 level) in the intervals of 2 times a week for 12 weeks and the effect of K drip fertigation was compared to control treatment in which the K remainder was applied with surface application as additional fertilizer. The growth of stem diameter, leaf number and shoot length were highest in K1/2 (50 mg/L K), but K of mineral contents was lowest in K0. Yield of grapevine was no difference in 2008, but significantly higher K1/2 than other treatments in 2009. However, fruit quality (color degree, brix, acid contents) was no difference among the treatment. CONCLUSION(s): From the results, It is expected that K1/2 levels of fertigation based on soil testing could be more efficient to get optimum yield and save potassium fertilizer than control (surface application) treatments when grapevine was drip-irrigated at open field condition.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.62 no.1
• /
• pp.1-8
• /
• 2017

We investigated the effect of silicate coating of rice seeds on bakanae disease incidence and the quality of seedlings raised in seedling boxes and transplanted into pots. The silicate-coated rice seed (SCS) was prepared as follows. Naturally infested rice seeds not previously subjected to any fungicidal treatment were dressed with a mixture of 25% silicic acid at pH 11 and 300-mesh zeolite powder at a ratio of 50 g dry seed - 9 mL silicic acid - 25 g zeolite powder. The following nursery conditions were provided : Early sowing, dense seeding in a glass house with mulching overnight and no artificial heating, which were the ideal conditions for determining the effect on the seed. The nursery plants were evaluated for Gibberella. fujikuroi infection or to determine the recovery to normal growth of infected nursery plants in the Wagner pot. Seedlings emerged 2-3 days earlier for the SCS than they did for the non-SCS control, while damping-off and bakanae disease incidence were remarkably reduced. Specifically, bakanae disease incidence in the SCS was limited to only 7.8% for 80 days after sowing, as compared to 91.6% of the non-SCS control. For the 45-days-old SCS nursery seedlings, the fresh weight was increased by 11% and was two times heavier, with only mild damage compared to that observed for non-SCS. Even after transplanting, SCS treatment contributed to a lower incidence of further infections and possibly to recovery of the seedlings to normal growth as compared to that observed in symptomatic plants in the pot. The active pathogenic macro-conidia and micro-conidia were considerably lower in the soil, root, and seedling sheath base of the SCS. In particular, the underdeveloped macro-conidia with straight oblong shape without intact septum were isolated in the SCS ; this phenotype is likely to be at a comparative etiological disadvantage when compared to that of typical active macro-conidia, which are slightly sickle-shaped with 3-7 intact septa. A active intact conidia with high inoculum potential were rarely observed in the tissue of the seedlings treated only in the SCS. We propose that promising result was likely achieved via inhibition of the development of intact pathogenic conidia, in concert with the aerobic, acidic conditions induced by the physiochemical characteristics associated with the air porosity of zeolite, alkalinity of silicate and the seed husk as a carbon source. In addition, the resistance of the healthy plants to pathogenic conidia was also important factor.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.1
• /
• pp.9-16
• /
• 2016

To investigate the effect of soluble silicate zeolite dressing of the rice against bakanae disease, field trial in reclaimed land and in vitro were carried out. The coated rice seeds (SCS) which were dressed with the mixture of 25% silicic acids (binder), and the zeolite (coating powder). In wet direct seeding, uniform scattering of rice seeds on the soil surface and the better seedling establishment were shown in SCS treatment plots. The incidence of bakanae disease began from the mid tillering stage toward the heading stage. Around heading stage, the ratio of infected tillers reached its highest point by 9.9% in non-SCS treatment plots. While, in SCS treatment plots, the ratio of infected tillers was no more than 0.01%. The vitality of the pathogenic fungi of bakanae disease in the SCS and non-SCS samples were assessed. Samples were incubated for one week keeping proper humidity at $30^{\circ}C$ after inoculated with panicles of infected rice plants from experimental field plots. In non-SCS treatment, pinkish colonies were formed on the grain surface of panicle of infected plants, and mycelium, macro-conidia and micro-conidia were developed actively inside part of infected grain inoculated. While in SCS treatment, micro-conidia and mycelium were not survived and the growth of macro-conidia, mycelia were greatly inhibited and withered. Based on the results, it is concluded that the environmental friendly control of bakanae disease by use of SCS is possible and soluble silicate can be applied as agents for replacement of seed disinfection.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.1
• /
• pp.30-39
• /
• 2020

A new silicate coating technology was developed which reduces the impact of dust and loosening during seeding compared to existing silicate-coatings (Seed/Si/Zeolite), and therefore can lower the production costs of rice cultivation. In this method, 100 g of rice seed is coated with 18 mL of liquid silicic acid and then dressed with a mixture containing 80 g of dolomite and 5 g of iron. To determine the most effective method of application and ensure that seedlings developed healthily, a series of experiments were carried out. Infected seeds scattered in seedling boxes and pots (soil and hydroponic) were coated dry, without disinfection. In comparison to the seed which were not treated with the silicate-coating, the new seed (A) were 1.84 times heavier in weight, and were also improved in terms of coating strength and coating color. Compared to the seedlings grown from the non-coated seed, those grown from the new silicate-coated seed were of significantly higher quality (weight/length) and had erect, dark greenish leaves, which are ideal plant characteristics. This was most likely due to increased silicate uptake. The symptoms of bakanae disease in the non-coated seed peaked after 38 days to 54.2%, whereas the control value was 68.8% in the new silicate-coated seed (A). In the infected seedlings grown from the new silicate-coated rice seed, subnormal macro-conidia, namely, a sickle shape spore without a septum; a straight oblong shape spore without a septum and with a thick cell wall; and inter-septal necrosis of a normal spore were detected. It is believed that the strong alkalinity of silicic acid have acted as unfavorable conditions for pathogenicity. In seedlings grown from the new silicate coated rice seed under hydroponic conditions without nutrients, normal root activity and growth was maintained without leaf senescence. Therefore, it was possible to reduce the rate of fertilization. In the future, a new silicate-coated rice seed was required for the study of minimal nutrition for anti-aging of seedlings.