• Korean Journal of Environmental Agriculture
• /
• v.17 no.3
• /
• pp.211-214
• /
• 1998

Changes in physico-chemical properties and major nutrient contents were investigated in the soil of paddy fields during fallow period. Weed vegetation change in the fallow paddy fields was also examined. As the fallow period became longer, organic matter content in the paddy soil has gradually increased. Soil pH of the paddy fields has not changed until three years of fallow period and thereafter slightly increased. Cation exchange capacity of the paddy soil, and exchangeable N, K, Ca and Mg contents in the soil tended to decrease until three years of fallow period and then increase with the prolonged fallow period. As the fallow period became longer, available $P_2O_5$ content in the paddy soil has continuously decreased. Available $SiO_2$ content in the paddy soil has not changed until three years of fallow period and thereafter increased. The vegetation in the fallow paddy fields have mostly been occupied by the weeds of the Gramineae, Cyperaceae, and Compositae. As the fallow period became longer, the weeds of the Polygonaceae and Juncaceae have increased, whereas the weeds of the Leguminosae, Commelinaceae, Pontederiaceae, and Onagraceae have gradually disappeared. However, the weeds of the Gramineae and Cyperaceae have always been dominant in the paddy fields during the fallow paddy period.

• Proceedings of the Korean Society of Grassland Science Conference
• /
• 2002.09b
• /
• pp.131-156
• /
• 2002

Although economically viable, the livestock industry is currently facing a number of challenging environmental problems and highly complex social issues, many of which are related to its size and geographically concentrated nature. Increased emphasis on environmental quality has also placed new demands on livestock producers to ensure that their production practices are in harmony with natural environment. In terms of sustainable agricultural systems, ruminants have served and will continue to serve a valuable role. They are particularly useful in converting vast renewable resources from rangeland, pasture, and crop residues or other by-product into food edible for human. With ruminants, land that is too poor or too erodable to cultivate becomes productive. Also, nutrients in by-products are utilized and do not become a waste-disposal problem. In Korea, however, native and dairy cattle production is not consistent with the advantageous roles of ruminant livestock in sustainable agricultural system because imported feed grains become the main basis for cattle raising. At present the ruminant livestock producers are heavily concentrated in and around the urban areas. About 75% of all the nation's cattle herds are kept on the outskirts of urban areas. As a result, the amount of pasture and forage land available per head of cattle is generally small. Furthermore, animals are raised in a cattle shed with high density. This situation is rather unfavorable for the national economic and environmental points of view As nation income increased, the demand for livestock products grew at an unforeseeable pace. But the pasture area involving in current utilization is tended to decrease during recent years. Based on the above figures more than 250,000 ha of pasture ought to be available for the present herd of cattle. It is obvious that these needs can scarcely be met with arable lands. Lands area for the establishment of new grassland have to be found in the hills and mountains which have not yet been used for crop framing or livestock. The development of extensive grasslands in the hill and woodland areas is now a declared aim. The starting point of the present work is the lack of knowledge of forage production and utilization in hill pasture and woodland in spite of indispensable necessity for livestock production in Korea. The importance of pastoral system in hill region and woodland is particularly emphasized in a standpoint of sustainable livestock production. Main chapter comprises the principle and techniques applicable for improving the utilization of hill pasture and woodland. We finally discussed the problems to solve and future works for a successful livestock production in hill and mountainous area in Korea.

• Asian-Australasian Journal of Animal Sciences
• /
• v.23 no.9
• /
• pp.1198-1204
• /
• 2010

This study was conducted to investigate the effects of dietary supplementation with multiple enzymes composed of phytase plus carbohydrolases (ROVABIO$^{(R)}$ Max, RM) on growth performance, nutritional availability and intestinal viscosity in broiler chicks. A total of one thousand, one-day-old male broiler chicks were randomly allotted into treatment groups that received one of five experimental diets for 32 days. Each group consisted of 40 birds and all experiments included five replicates. The dietary treatments included PC (a positive control diet), NC1 (65 kcal/kg, 0.15% and 0.10% less ME, available phosphorus and calcium levels, respectively, than the PC diet), NC2 (85 kcal/kg, 0.20% and 0.10% less ME, available phosphorus and calcium levels, respectively, than the PC diet), NC1+RM (NC1 plus ROVABIO$^{(R)}$ Max) and NC2+RM (NC2 plus ROVABIO$^{(R)}$ Max). The average body weights, daily body weight gains and feed conversion rates of the chicks fed a diet containing RM improved significantly or tended to improve. The treatments also had no effect on the carcass characteristics or blood parameters, but the viscosity of the intestinal contents of the chicks fed the diet containing RM was significantly lower than that of chicks in the NC without RM groups. Additionally, chicks fed the dietary RM showed increased breaking strength and ash content of the tibia when compared to chicks that received the non-RM diets. Taken together, the results of the present study indicated that the addition of multiple enzymes consisting of phytase plus NSP enzymes improved the growth performance and mineral status of the tibia in broiler chickens fed corn-wheat-soybean meal-based diets with reduced levels of nutrients. Further, these findings suggest that the improved animal performance is associated with reduced intestinal viscosity by the dietary enzyme complex.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.2
• /
• pp.242-247
• /
• 2011

Soil management for environment-friendly agriculture depends on the effects of soil microbial activities and soil fertility. To improve soil health for the upland crops, this study evaluated a relationship between soil chemical properties and soil microbial diversities at 25 sites in upland soils in Gyeongnam Province. The average nutrients in the upland soils were 1.7 times for available phosphorous, 1.4 times for exchangeable potassium and 1.5 times for exchangeable calcium higher compared to recommend concentrations in the upland soils. We found a significant positive correlation between the soil organic matter and the soil microbial biomass C (p<0.01). Contents of organic matter and dehydrogenase in the inclined piedmont soils were significantly higher than those in the other topographical soils (p<0.05). In addition, concentrations of organic matter and microbial biomass C in the loam soils were significantly higher than in the silt loam soils (p<0.05). In principal component analyses of chemical properties and microbial populations in the upland soils, our findings suggested that available phosphorous should be considered as potential factor responsible for the clear upland soils differentiation. The soil organic matter was positive correlation with Bacillus sp. and fungi, whereas soil pH was also positive correlation with Pseudomonas sp. in upland soils.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.3
• /
• pp.181-188
• /
• 1993

The effects of paddy-upland rotation and cropping system on the mineralization of soil organic nitrigen, on the change of organic matter and available phosphorus content in the soil, and on the rice yield and nutrients absorption were studied in Seokcheon fine-sandy loam soil. 1. In the incubation test mineralzed soil nitrogen and the nitrogen extracted by pH 7 phosphate buffer solutions were higher in the soils from every and two year rotation systems than continuous rice cultivation. In terms of cropping system potato-chiness cabbage-rice increased them more than soybean-rice system. 2. The change of soil organic matter and available phosphorus contents were not much in continuous rice cultivation, while in rotation system they decreased as the paddy-upland rotation frequency decreased. In terms of cropping system they decresed more in potato-Chinese cabbage-rice system compared with soybean-rice systems. 3. The rice yield was higher in the paddy-upland rotation system than that of continuous rice cultivation. However, the effects were decreased gradually every year, as shown by 26~20, 17~5, and 5~4% yield increase for first, second, and third year, respectively, in potato-Chinese cabbage-rice and soybean-rice system compared with continuous rice cultivation. 4. All the absorbed nutrient contents increased in every and two year rotation system compared with continuous rice cultivation. In terms of cropping system potato-Chiness cabbage-rice system increased them more compared with soybean-rice system.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.22 no.3
• /
• pp.194-204
• /
• 2020

Cultivar parameters, which are key inputs to a crop growth model, have been estimated using observation data in good quality. Observation data with high quality often require considerable labor and cost, which makes it challenging to gather a large quantity of data for calibration of cultivar parameters. Alternatively, data in sufficient quantity can be collected from the reports on the evaluation of cultivars by region although these data are of questionable quality. The objective of our study was to assess the quality of crop and management data available from the reports on the regional adaptation trials for rice cultivars. We also aimed to propose the measures for improvement of the data quality, which would aid reliable estimation of cultivar parameters. DatasetRanker, which is the tool designed for quantitative assessment of the data for parameter calibration, was used to evaluate the quality of the data available from the regional adaptation trials. It was found that these data for rice cultivars were classified into the Silver class, which could be used for validation or calibration of key cultivar parameters. However, those regional adaptation trial data would fall short of the quality for model improvement. Additional information on management, e.g., harvest and irrigation management, can increase the quantitative quality by 10% with the minimum effort and cost. The quality of the data can also be improved through measurements of initial conditions for crop growth simulations such as soil moisture and nutrients. In addition, crop model improvement can be facilitated using crop growth data in time series, which merits further studies on development of approaches for non-destructive methods to monitor the crop growth.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.57 no.6
• /
• pp.47-57
• /
• 2015

Organic farming system has been considered environmental friendly and sustainable agricultural practice. However, the influence of organic farming on soil quality and environment is not well informed and controversial. We sampled and analyzed 0~15 cm and 15~30 cm depth soils of organic and conventional paddy fields in Yongin and Anseong. The electric conductivity and organic matter content of organic paddy soil were significantly less (p = 0.0097, 0.0067, respectively) than those of conventional paddy soil. Available phosphate and total phosphorus in 0~15 cm depth of organic paddy soil were $211.1{\pm}135.3$, $872.4{\pm}286.3mg/kg$, respectively, less than those of conventional paddy soil. Available phosphate amount in conventional paddy was $358.8{\pm}246.7mg/kg$, which is higher than 300 mg/kg that can cause secondary environmental contamination by runoff. The amount of total nitrogen in organic paddy soil was less than that in conventional paddy while their difference was not significant. The concentration of the heavy metals in organic paddy soil was also lower than that in conventional paddy soil but their difference was not statistically significant. Our findings demonstrate that electric conductivity, organic matter, nutrients, and heavy metals in organic paddy soil were less than those in conventional paddy soil. However, additional monitoring of soil properties for longer period is necessary to certify such a conclusion.

• Journal of Animal Environmental Science
• /
• v.18 no.2
• /
• pp.63-74
• /
• 2012

This experiment was carried out to investigate the effect of different stocking rate on growth, cast production and conversion efficiency of organic matter to tissues of earthworm. The carbon and nitrogen ratio (C/N) of tested Korean cow manure was 25.1, it was estimated an adequate ratio as feed for earthworms. The different stocking rates were 1:8(S-1), 1:16(S-2), 1:32(S-3) 1:64(S-4) 1:128(S-5) and 1:256 (S-6) as the ratios of earthworm fresh weight to biomass of Korean cow manure, respectively. A stocking rate of 1:32(S-3) was obtained a significantly highest values of increasing rate and conversion efficiency of organic matter to earthworm tissues. The mean values of increasin g rate of fresh weight and conversion efficiency of organic matter to earthworm tissues were 10.63 mg/day and 6.65% at the ratio of 1:32(S-3) with a rearing volume was $56.6cm^3$. A stocking rate of 1:8(S-1) was obtained a highest ratio of vermicasts, but showed a negative values of increasing rate and conversion efficiency of organic matter to earthworm tissues, it may due to severely food competition between individuals during the rearing periods. The pH, total nitrogen, available phosphorus, cation exchange capacity and exchangeable cations of vermicasts tended to increase with stocking rate. Especially, available phosphorus, cation exchange capacity and exchangeable cations of vermicasts tended to increase with rearing progressed. Vermicasts have the potential for improving plant growth when amended to container medium and soil according to increased availability of nutrients and improved physicochemical properties.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.2
• /
• pp.109-113
• /
• 2007

In order to establish the fertilization and soil management method in Gyehwa reclaimed tidal land, we investigated soil property and actual farming condition. Soil properties of 100 field paddy soil and farming surveys of 177 farm households were conducted. Average of effective soil depth was 17.8 cm, which was very smaller than the optimum level 50 cm. The hardness and bulk density of subsoil were $12.40kg\;cm^{-2}$ and $1.59g\;cm^{-3}$, respectively. These results showed that soil physical condition of Gyehwa reclaimed tidal land was very poor. Soil salinity ranged from 0.03 to 0.12%, and average of pH was 6.0, which implied that desalinization of Gyehwa reclaimed tidal land was progressed. However, soil nutrients in Gyehwa reclaimed tidal land were very unbalanced conditions as following, available phosphate $58mg\;kg^{-1}$, available silicate $85mg\;kg^{-1}$, cation exchangeable capacity $7.4cmolc\;kg^{-1}$ and organic matter $8.6g\;kg^{-1}$. On the farm household in Gyehwa reclaimed tidal land, fertilization amounts were $200-54-61(N-P_2O_5-K_2O)kg\;ha^{-1}$ They mainly practiced spring tillage(84%) rather than autumn tillage(16%), and only 14% of them applied rice straw annually in the paddy soil.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.5
• /
• pp.322-328
• /
• 2004

Available nutrients in soil solution play key roles on the growth of plants, but the equilibria in soil solution can be disturbed by acid precipitation. In this study, we investigated the relationships between element concentrations in the needles of Pinus thunbergii and chemical properties of forest soil solutions in the industrial complexes as an effort to find the possible limiting factor(s) causing the forest decline. The Ca/Al molar ratios in needles of Pinus thunbergii collected from the control sites were 18. However, at Onsan and Ulsan industrial complexes, those were decreased to the ranges from 10 to 11 for the one-year old needles and from 9 to 10 for the two-year old needles. The Mg/Al molar ratios showed similar tendencies with the Ca/Al molar ratios of the needles of Pinus thunbergii. In the A horizon, there existed a significant correlation between Mg concentrations in the needles of Pinus thunbergii and Ca/Al molar ratio of forest soil solution. Calcium concentrations in the needles of Pinus thunbergii in the B horizon were also significantly correlated with Ca/Al molar ratios of forest soil solutions. The uptakes of Ca and Mg by Pinus thunbergii were mainly limited by Al in the soil solutions of the A horizon and by Mn and Al in the soil solutions of the B horizon.