In-Bog Lee

Evaluation of stability of compost prepared with Korean food wastes

Abstract Food wastes were composted with saw dust, dried paper mill sludge, and decayed wood dust to reduce the volume of wastes and to produce a stable organic soil amendment. To determine the stability for agricultural utilization, the compost maturity was evaluated using physical, chemical, and biological parameters. Temperature of the inner compost heap remained high at over 50°C during the 80 d of composting, but the chemical and physical parameters apparently changed between 30 and 50 piling d: pH was a weakly acidic of the initial stage and neutral after 30 d of composting. The C / N ratio decreased to less than 12 after 65 d of composting, but the C / N ratio of the products was less than 0.5 time that of the initial value after 35 d of composting. Reducing sugar contents changed significantly between 40 and 45 d of composting, and the Y value that indicated color changes of the water extracts decreased and became stabilized at around 3 after 50 d of composting. Ring types and color on circular paper chromatograms showed an apparent difference before and after 40 d of composting. The content of sodium (Na), which might be one of the most harmful elements in Korean food wastes for agricultural utilization, increased from 12 to 17 g kg−1 with time and Na mostly occurred in a water-soluble form. Acetic acid was the main component of volatile organic acids, and total organic acids were produced at a very high rate (500–700 mg kg−1) during the first 5–30 d of composting and then the rate decreased rapidly to below 300 mg kg−1 after 35 d of compo sting. Germination index of Chinese cabbage in water extracts fluctuated with compost pile turning to a value below 50 by 40 d of composting, due to the effects of high contents of organic acids and Na. The value exceeded 50 after 45 d of compo sting but did not increase further with continuous composting, which might be due to the high content of Na. Lettuce, a sensitive species, was scarcely germinated in water extracts of the food compost. Consequently, the high content of Na in Korean food waste compost, in spite of maturity, could be a limiting factor for agricultural utilization. The effects of Korean food waste compost on plant growth and soil conditions should be evaluated further at the field level.

Effects of Continual Pre-plant Application of Pig Slurry on Soil Mineral Nutrients and Yield of Chinese Cabbage

1) , Jin-Myeon Park ABSTRACT: Land application of animal manure, such as pig slurry(PS), has been considered as valuable organic source to supply necessary nutrients for crop growth. On the other hand, little information is available on the effect of consecutive application of PS on agricultural soils. This study was conducted to evaluate the influence on change in soil chemical properties and yield of Chinese cabbage in soils amended with slurry composting and bio-filtration pig slurry (SCB) for four consecutive crop cultivations (2007-2008). Among total application rates required, a basal fertilizer (35%) was applied with SCB or chemical fertilizer (CF). The CF was applied as a side dressing was applied in all treatments. There was no significant effect of SCB and CF on Chinese cabbage yield during four cropping seasons. In addition, soluble sugar, vitamin C contents and yields of Chinese cabbage between SCB and CF did not show statistically significant difference. During the experiment, soil chemical properties between SCB and CF treatment showed similar pattern, however, the contents of exchangeable sodium (Na) in soil has been increased (P<0.05) since the second cropping season because of higher Na contents in SCB. Therefore, the use of SCB as a substitute of CF is available for growth and yield of chinese cabbage while its long-term application might leads to an accumulation of Na in soil.

Effect of Reduced Nitrogen Fertigation Rates on Growth and Yield of Tomato

To investigate the effect of N fertigation on the growth, yield, and water and nitrogen use efficiencies during tomato cultivation, seedlings were transplanted in a sandy loam soil under plastic film house condition. 0, 88, 132, 176, N rates, which correspond to 0 (NF0), 40 (NF40), 60 (NF60), 80 (NF80), 100% (NF100) N level of soil test-based N fertilization, were injected weekly through drip irrigation system for 15 weeks in N fertigation system, and the control (conventional N treatment) was installed for comparison. Herein, nitrogen was applied by top-dressing with 60% as a basal and 40% as additional fertilizer. There was little different in stem diameter growth among N fertigation treatments, but plant height and dry matter increased with increasing N fertigation rates as well as in N conventional treatment. Tomato yield was increased with increasing the number of marketable fruits in N fertigation treatments, and the fruit yield was maximized in NF 80 treatment ( N supply or N injection). Dry matter productivity and nitrogen uptake amount were significantly increased with increasing N fertigation rates. The ratio of fruits to the dry weight of whole plant was decreased with increasing N fertigation rates, but this ratio was higher in N fertigation treatments than in the control. In addition, the ratios of nitrogen distributed toward fruits in N fertigation treatments were higher than that of control. The apparent N recovery percentages showed significantly higher values as in N fertigation treatments, compared to 45% in N conventional treatment. Water use efficiency was significantly increased by fertigation system with the maximum in NF 80, which is comparable to of the conventional treatment. Conclusively, N fertigation system was effective on increasing tomato productivity and nutrient efficiency as well as 20% reduction of N fertilization level.

Effect of Soil Incorporation of Graminaceous and Leguminous Manures on Tomato (Lycoperiscon esculentum Mill.) Growth and Soil Nutrient Balances

To investigate the effects of incorporation of green manures (GM) into a sandy loam soil on growth, yield, and nutrient uptake of tomato (Lycoperiscon esculentum Mill.) and nutrient balances (input minus offtake of nutrients), five tomato production systems were compared under the condition of plastic film house: 1) a no input system (no additional amendment or inputs, 0-To-0-To); 2) a conventional system (application of N-P-K chemical fertilizers, Cf-To-Cf-To); 3) a leguminous GM-containing system (hairy vetch-tomato-soybean-tomato, Hv-To-Sb-To); 4) a graminaceous GM-containing system (rye-tomato-sudan grass-tomato, Ry-To-Sd-To); and 5) system mixed with leguminous and graminaceous GMs (rye-tomatosoybean- tomato, Ry-To-Sb-To). Here, hairy vetch and rye were cultivated as winter cover crops during late Feb and soybean and sudan grass were cultivated as summer cover crops during late Aug. All of them cut before tomato planting and then incorporated into soil. Biomass of GMs was greater in summer season than that of winter season. Nitrogen amount fixed by a leguminous plants was about per a cropping season, corresponding to 60% N level needed for tomato production, which was comparable to 50 and fixed by rye and sudan grass. As a result, tomato yield of Hv-To-Sb-To system (legume GM treatment) was similar to Cf-To-Cf-To (conventional), but that in Ry-To-Sd-To system (graminaceous GM treatment) was not attained to a half level of conventional treatment. Nutrient budgets for N, P and K on the conventional farm were balanced or somewhat positive exception for minus-balanced K. Ry-To-Sd-To system showed a positive N, P and K budgets due to the depressed growth of tomato which is caused by high C/N ratio and low N-fixing capacity of the GMs. Inversely, those of Hv-To-Sb-To system were negative in all of N, P and K budgets because of increased growth and yield of tomato with high nitrogen-supplying capacity as well as low C/N ratio of leguminous GM. In conclusion, although conventional cultivation has an advantage in relation to N, P and K nutrient budgets rather than GM-incorporated systems, a leguminous GMs could be recommended as nitrogen reservoir and soil amendment because the yield of tomato between use of leguminous GM and conventional cultivation was not only significantly difference, but also GMs commonly reduce nutrient loss and improve microbial communities.

Effects of Fertigation with Pig Slurry on Growth and Yield of Red pepper

Slurry composting biofiltration(SCB) is considered as a treatment to produce a better fertilizer resource than raw pig slurry as it reduces odor and improves nutrients imbalance. For the agricultural use of SCB slurry as a nutrient source with minimum environmental impact, it is important to investigate the effect of different rate of SCB slurry application on nutrient (particularly for nitrogen) uptake and growth of crops. This study was conducted to investigate the influence of fertigation using pig slurry(PS) on growth and yield of red pepper and to evaluate the appropriate PS concentration in fertigation for soils with different nitrate concentration. To evaluate the effects of fertigation applied PS as a substitute of chemical fertilizer(CF), a single application of three different concentrations of PS: (43 mg/L), (86 mg/L) and (131 mg/L) were compared with CF (89 mg/L) as a control nitrogen fertilizer. Statistical analysis showed that the growths of red pepper were not affected by treatments. In addition, the yields were no significant difference among treatments, though the highest yield was obtained in PS by 20,580 kg/ha. In soil chemical properties, nitrate nitrogen on soil of between PS N1.0 and CF treatment showed similar patterns although they were higher than the preplant nitrogen content. Also, there was no significant difference in yield of red pepper between PS and CF treatment applied as fertigation on soils where nitrate nitrogen contents of each soil contains 10, 100 and 200 mg/kg respectively. Consequently, the application of PS, such as SCB, as a substitute of CF is available for growth and yield of red pepper, there could be accordingly estimated the optimal fertigation concentration of PS for red pepper cultivation.

Effect of Elevated Carbon Dioxide Concentration and Temperature on Yield and Fruit Characteristics of Tomato (Lycopersicon esculentum Mill.)

The objective of this study is to investigate the effect of the level of CO2 (370 and 650 mol μ mol -1 ) and temperature (ambient and ambient+5 ) on tomato growth and fruit characteristics as affected by ℃ the application rate of N-fertilizer (68 and 204 N kg ha -1 ), for the purpose of evaluating the influence of elevated CO2 and temperature on tomato crop. The elevated atmospheric CO2 and temperature increased the plant height and stem diameter for tomato crop, while the differences among the nitrogen(N) application rates were not significantly different. Under the elevated CO2, temperature, and a higher N application rate, the biomass of aerial part increased. The fruit yield showed the same result as the biomass except for the elevated temperature. The elevated temperature made the size of fruit move toward the small, but the elevated CO2 and the application of N-fertilizer were vice versa. The sugar content and pH of fruit juice were affected by nitrogen application rate, but not by the elevated CO2 and temperature. These results showed that both the elevated CO2 and temperature stimulated the vegetative growth of aerial parts for tomato, but each effects on the yield of fruit showed an opposite result between the elevated temperature and CO2. In conclusion, the elevated CO2 increased tomato yield and the ratio of large size of fruit, but the elevated temperature did not. Therefore, to secure the productivity of tomato as nowadays in future environment, it will need to develop new breeder as high temperature-tolerable tomato species or new type of cropping systems.

Relationship between Soil Management Methods and Soil Chemical Properties in Protected Cultivation

Various cultural practices have been promoted as management options for enhancing soil quality and health. The use of soil management methods can cause changes in fertility by affecting soil chemical properties. This study aimed to evaluate interactions between soil chemical properties and soil management methods in protected cultivation, and to classify soil management methods that similarly affect soil chemical properties. Water-logging and irrigation reduced soil pH and available content. Application of animal manures has a positive effect on levels of organic matter, Av., K, Zn, and Cu. The electrical conductivites tened to be low in the application of organic amendments, including rice and wood residues. Deeper plowing caused a reduction in Ca content. Practicing soil nutrient-considering fertilization and fertigation did not exert an influence on nutrient element contents. In a cluster analysis of the soil management methods according to major nutrients, low similarities were found with deeper plowing and crop rotation with rice in comparison with other practices. In a cluster analysis by minor nutrient characteristics, crop rotation and application of animal manures and rice residues were linked at a high Wards distance, while other practices were found to be relatively low distinct. Each soil management method has a similar or different effect on soil chemical properties. These results suggest the necessity of establishing limits and standards according to the effects of soil management methods on soil chemical properties for economic soil practices.

Estimation of Phosphorus Adsorption Capacity of Alum-amended and Composted Paper Mill Sludge

Excess application of paper mill sludge (PMS) in field can limit phosphorus uptake by crops because aluminum presented in the sludge can fix or adsorb available phosphorus which is necessary for crop growth. To investigate phosphorus (P) adsorption characteristics of PMS, we examined P adsorption maximum using Langmuir isotherm and P adsorption energy constant using Freundlich isotherm for PMS without alum, PMS with alum, and composted PMS with alum through a laboratory incubation test. The maximum P adsorption capacities were 800 in soil, 47 in PMS without alum and 61 in PMS with alum. P adsorption capacity with alum treatment for PMS increased by 30%. That of PMS compost was 68 and showed that composting increases 11% of P adsorption. Freundlich constant was 22 in check soil, while values in PMS without alum and in PMS with alum were 398 and 426, respectively. After composting, value of PMS compost significantly increased as 1,819. In conclusions, p adsorption capacity for PMS were increased by alum treatment or composting and therefore excess or continuous land application of alum-amended or composted PMS can limit P uptake for crops by reducing available P in sell.

Effect of Water Treatment Sludge on Growth of Rice Seedling

To know the effect of water treatment sludge (WTS) as a rice seedling culture soil, rice seeds are sown, germinated and grown on the culture soils mixed with different ratios of WTS to sand (100:0, 50:50, 30:70, respectively), and their growth effects was compared to that of control, commercial culture soil. When WTS is used as a culture soil for rice, the length and weight of the top part of rice seedling somewhat decreased than those of control treatment while their root length and weight in all WTS treatments significantly increased. Although phosphorus and potassium uptake of rice seedling in WTS treatments was slightly decreased, WTS treatment showed to develop root growth which is necessary in the seedling stage of all plane. Such a stimulatory effect on root growth of rice seedling was significant in the mixture ratio of 50% WTS to 50% sand.