DANIEL SON | Masinde Muliro University of Science and Technology (original) (raw)

Papers by DANIEL SON

Korean Journal of Soil Science and Fertilizer, 2018

Long-term monitoring of soil chemical properties is the main agricultural practices to improve cr... more Long-term monitoring of soil chemical properties is the main agricultural practices to improve crop yield and soil fertility. Field monitoring was performed to evaluate the chemical properties of 200 greenhouse soil samples every 4 years from 2000 to 2016 in Gyeongnam province, South Korea. Soil properties such as pH, electrical conductivity (EC), amount of organic matter (OM), available phosphate (P 2 O 5), nitrate nitrogen (NO 3-N), exchangeable potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) were analyzed. In 2016, the average concentration of soils under greenhouse condition showed 6.8 for pH, 3.52 dS m-1 for EC, 40 g kg-1 for OM, 1,065 mg kg-1 for P 2 O 5 , 154 mg kg-1 for NO 3-N, 2.35 cmol c kg-1 for K, 12.8 cmol c kg-1 for Ca, 4.0 cmol c kg-1 for Mg, and 0.91 cmol c kg-1 for Na. In addition, the average concentrations of OM, K, Ca, and Na have tended to increase with year. In 2016, the frequency distribution of excessive level of soils under greenhouse condition was 43% for pH, 61% for OM, 94% for P 2 O 5 , 89% for K, 96% for Ca, and 83% for Mg. Soil EC values of green pepper, tomato, and lettuce were significantly higher than those of carrot, strawberry, and squash (p < 0.05), whereas soil pH was significantly lower in the carrot and lettuce than that in the strawberry (p < 0.05). Soil pH was significantly correlated with the EC, NO 3-N, K, Ca, Mg, and Na. The value of EC was also positively correlated with the OM, P 2 O 5 , NO 3-N, K, Ca, Mg, and Na. In conclusion, the long-term information on soil chemical properties will be helpful to improve sustainable soil and nutrient management for greenhouse farming.

International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013, 2014

This study was conducted to develop method of producing okra under open field condition and the 1... more This study was conducted to develop method of producing okra under open field condition and the 10 cultivars of okra for selecting proper cultivar in Jeju, Korea. The okra pod's color is divided into red and green and shape is into round and fiveangled. The tall of plant ranged 170-237 cm and 'Pusa-sawani' is tallest. The pod's length ranged 9.2~11.0 cm and width is 12.7-16.9 mm. The pod's weight ranged 11.6-14.6 g and 'THA-Kasassert' is heaviest. The number of pods ranged 6.6-18.9 pods/ plant, 'Shimano-beny' is largest number. 'Shimano-beny' and 'Pusa-sawani' cultivar was the highest yield as red and green strains to 229 g/plant and 191 g/plant. The green strains, 'Pusa-sawani', 'THA-Kasassert' and 'Finger-five' were excellent in the pod's color, weight and yield and 'Retdosan' in the red strain were grown best of open field on the temperate area.

Korean Journal of Soil Science and Fertilizer, 2018

Long-term monitoring of soil chemical properties is the main agricultural practices to improve cr... more Long-term monitoring of soil chemical properties is the main agricultural practices to improve crop yield and soil fertility. Field monitoring was performed to evaluate the chemical properties of 200 greenhouse soil samples every 4 years from 2000 to 2016 in Gyeongnam province, South Korea. Soil properties such as pH, electrical conductivity (EC), amount of organic matter (OM), available phosphate (P 2 O 5), nitrate nitrogen (NO 3-N), exchangeable potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) were analyzed. In 2016, the average concentration of soils under greenhouse condition showed 6.8 for pH, 3.52 dS m-1 for EC, 40 g kg-1 for OM, 1,065 mg kg-1 for P 2 O 5 , 154 mg kg-1 for NO 3-N, 2.35 cmol c kg-1 for K, 12.8 cmol c kg-1 for Ca, 4.0 cmol c kg-1 for Mg, and 0.91 cmol c kg-1 for Na. In addition, the average concentrations of OM, K, Ca, and Na have tended to increase with year. In 2016, the frequency distribution of excessive level of soils under greenhouse condition was 43% for pH, 61% for OM, 94% for P 2 O 5 , 89% for K, 96% for Ca, and 83% for Mg. Soil EC values of green pepper, tomato, and lettuce were significantly higher than those of carrot, strawberry, and squash (p < 0.05), whereas soil pH was significantly lower in the carrot and lettuce than that in the strawberry (p < 0.05). Soil pH was significantly correlated with the EC, NO 3-N, K, Ca, Mg, and Na. The value of EC was also positively correlated with the OM, P 2 O 5 , NO 3-N, K, Ca, Mg, and Na. In conclusion, the long-term information on soil chemical properties will be helpful to improve sustainable soil and nutrient management for greenhouse farming.

International Symposium on New Technologies for Environment Control, Energy-Saving and Crop Production in Greenhouse and Plant Factory - Greensys 2013, 2014

This study was conducted to develop method of producing okra under open field condition and the 1... more This study was conducted to develop method of producing okra under open field condition and the 10 cultivars of okra for selecting proper cultivar in Jeju, Korea. The okra pod's color is divided into red and green and shape is into round and fiveangled. The tall of plant ranged 170-237 cm and 'Pusa-sawani' is tallest. The pod's length ranged 9.2~11.0 cm and width is 12.7-16.9 mm. The pod's weight ranged 11.6-14.6 g and 'THA-Kasassert' is heaviest. The number of pods ranged 6.6-18.9 pods/ plant, 'Shimano-beny' is largest number. 'Shimano-beny' and 'Pusa-sawani' cultivar was the highest yield as red and green strains to 229 g/plant and 191 g/plant. The green strains, 'Pusa-sawani', 'THA-Kasassert' and 'Finger-five' were excellent in the pod's color, weight and yield and 'Retdosan' in the red strain were grown best of open field on the temperate area.