The object of this study conducted to investigate the effect of paddy-upland rotation cropping system on soil properties and crop productivity in newly reclaimed tidal land. Five types of paddyupland rotation cropping system were evaluated : Rice-Rice (RR) Rice-Maize (RM), Mize-Maize (MM), Rice-Soybean (RS), Soybean-Soybean (SS). The soil bulk density was the lowest RM treatment, and soil pH was a tendency to be lower in all treatments of the paddy-upland rotation cropping system. RM treatment showed a higher moisture content and lower Electrical conductivity than RR treatment. Results of maize productivity in paddy-upland rotation cropping system, Except for the stem diameter growth, RM treatment showed good growth and productivity than MM treatment. Soybean growth and yield increased in the rotated upland cultivation from rice-paddy field compared to the SS treatment. But, overall treatments indicated poor growth and yield. In this study, we offer the effects of paddyupland rotation cropping system on the soil properties and upland crop growth and yield, and also out results can be provide supporting basic data that introduced paddy-upland rotation in reclaimed tidal land.

질산태 질소의 공급수준이 알팔파의 영양생장기 동안의 질소동화와 성장 및 재생기간 동안의 뿌리조직내 전분과 질소 축적에 미치는 영향을 규명하고자 0.2, 1.0 및 3.0 mM KN 하에서 10주 동안의 영양생장 후 건물 및 질소 화합물의 식물조직내의 분포를 분석하고, 24일간 1차 및 2차 재생을 각각 시킨 후 뿌리조직에 축적된 전분과 질소 함량을 분석하였다. 10간의 영양생장 후 건물과 질소화합물의 함량을 1.0 mM 처리구를 기준으로 비교한 결과,

To restore reclaimed land, it needs to be supplemented with organic matter; this is especially true for Korea, where organic matter constitutes only one-tenth of conventional agricultural soils. The giant Miscanthus, a perennial grass known for its extensive biomass, shows signs of being an excellent source of organic matter for restoring reclaimed land. Therefore, the objectives of this study were to (i) evaluate the feasibility of using the giant miscanthus as an organic resource within the context of re-using reclaimed land for agricultural purposes (i.e., potato cultivation), and (ii) determine the optimum fertilization rate for the potatoes while the giant miscanthus is being used as an organic resource. Our results show that after 180 days, giant miscanthus lost 23–47% of its original dry weight, with the extent of the loss dependent on soil salinity. Nutrient concentrations (Mg2+, Na+) continued to increase until the end of the study period. In contrast, potassium (K+) and the ratio of carbon to nitrogen (C/N) decreased until the end of the study period. Specifically, after 180 days, low salinity topsoil treatments had the lowest C/N ratio. In the first year, 150 % of standard N rates were required for the potatoes to achieve maximum productivity; however in the 2nd year, standard rates were sufficient to achieve maximum productivity. Overall, this implies that even though the application of giant miscanthus did eventually improve soil quality, increasing crop yields, N fertilization is still necessary for the best outcomes.

To investigate the changes in the composition and pool size of nitrogen metabolites under drought stress, white clover (Trifolium repens L.) were exposed to -0.04MPa (well-watered, control) or to -0.12MPa (drought-stressed) of soil water potential during 28 days. Dry weight of leaves in drought-stressed plants was remarkably decreased by 45% and 74% within 14 days and 28 days, respectively, compared with control. For nitrate concentration after 28 days of treatment, a significant difference (1.6 times higher in drought-stressed plants) was observed only in stolon. NH3 -NH4 + concentration in all three organs of drought-stressed plants linearly increased to more than 1.6 times higher level at 28 day when compared to the initial level (day 0), while the increasing rate in control was much less than that of drought-stressed plants. Proline concentrations in drought-stressed plants remarkably increased and reached to 7, 13 and 17 times higher level at 28 day compared to control. Protein concentration in leaves of drought-stressed plants tended to decrease, while it slightly increased during the first 14 days and reached a plateau afterward in control. There was not significant difference in the proteins concentration of stolon and roots throughout experimental period. On SDS-PAGE analysis, two major proteins specifically induced by drought stress (16-kD and 18-kD) were detected in stolon.n.

To investigate the changes in the composition and pool size of carbohydrates under drought stress, white clover (Triforium repens L.) were exposed to -0.04 Mpa(well-watered, control) or to -0.12 Mpa (drought-stressed) of soil water potential during 28 days. Dry weight of leaves in drought-stressed plants was remarkably decreased by 45% within 14 days and 74% within 28 days compared to those of the control. Glucose concentration in drought-stressed plants was increased, while that of control was slightly decreased or remained at same level throughout experimental period. Fructose and sucrose concentrations in leaves were not significantly changed for drought-stressed plants, but those of the control were significantly decreased on plant after 14 days. Fructose and sucrose concentrations in stolon of control plants were sharply decreased, while that of drought-stressed plants was less varied. Those concentrations in roots were generally increased in drought-stressed plants. The concentration of total soluble sugars at 28 day was 438.0 and 632.6 mg g-l dwt. in control and drought stressed plants, respectively. Starch concentration of stolon and roots of control plants was significantly increased to 2.0 and 1.4 times of initial level, respectively, whereas those of drought stressed plants was nearly same level or slightly decreased compared to initial level.l.

To investigate the partitioning of newly absorbed N derived from NO3 - and NH4 + , 6 mM K15 NO3 or 3 mM (15 NH4 )2 was fed continuously in Italian ryegrass (Lolium multiflrum L.) for 7 days. Nitrogen metabolites (nitrate, amino acid, soluble- and insoluble protein) were analyzed at the end of 15 N feeding. Dry weight in shoot, stubble and root was not significantly different between NO3 [-10] and NH4 + feeding. Total nitrogen content in all three organs was significantly higher in NH4 + than NO3 [-10] feeding. Sum on N content in reduced N fractions (amino acids + proteins) in shoot, stubble and roots in NH4 + feeding increased by 13.3, 12.5 and 35.4 %, respectively, compared to NO3 [-10] feeding. The Relative Specific Activity (RSA, percentage of newly absorbed 15 N relative to total N in a sample) values of amino acids and insoluble proteins were significantly higher in NH4 + feeding. Total amount of newly absorbed 15 N in NO3 [-10] and NO3 [-10] feeding was 52.3 and 69.5 mg/plant on dry matter basis, respectively. In both NH4 + and NO3 [-10] grown plants, most of the N was allocated to the shoot, 67.5% in NH4 + feeding and 58.8% NO3 [-10] feeding, respectively. The 15 N amount incorporated in the reduced N compounds (amino acids and proteins) in NH4 + grown plants significantly increased by 74.8% compared to NO3 [-10] grown plants. The increase of the 15 N amount assimilated to amino acids in NH4 + grown plants was remarkably higher in roots as more than 7.25 times compared to NO3 [-10] feeding. These results indicated that Italian ryegrass was much efficiently utilized NH4 + -N for the synthesis of reduced N compounds.reduced N compounds.

To investigate of C and N metabolisms in response to phosphorus-deficient stress during regrowth of Italian ryegrass (Lolium multiflorum L.), C and N metabolites were analyzed at 0, 6, 12 and 24 days after defoliation. P-sufficient (control, +P) and P-absent (-P) nutrient solutions were applied from 7 days before defoliation, and continued for one cycle of 24 day-regrowth period. During 24 days of regrowth, dry matter of regrowing shoots and remaining tissues were not significantly different between +P and -P treatment. In remaining stubble, 70% to 91 % decline of the initial level (at day 0) in all C compounds occurred during the first 6 days of regrowth. Initial amounts of nitrate and amino acids in roots were significantly higher in the +P medium. Nitrate contents in stubble in the +P medium significantly decreased for the first 12 days and then rapidly recovered, while that of the -P medium continuously decreased until day 24. Amino acids in stubble in the P medium were continuously increased during the whole regrowth period. Soluble proteins in stubble in the +P medium also largely fell down (46.0% of the initial) for only the first 6 days, however the decline in the -P medium continued until day 12. In regrowing shoots, the accumulation of C compounds was significantly higher, while that of N compounds except amino acids was largely lower in the -P medium. These results showed a stimulation of carbohydrate synthesis and a compensatory utilization of organic reserves occurred to support regrowth under P-deficient condition.