Min Seok Cho

Minimizing nutrient leaching and improving nutrient use efficiency of Liriodendron tulipifera and Larix leptolepis in a container nursery system

Fertilization is essential to seedling production in nursery culture, but excessive fertilization can contaminate surface and ground water around the nursery. The optimal fertilization practice is that which maximizes seedling growth and minimizes nutrient loss. We tested three fertilization strategies: (1) constant fertilization (2) a three-stage rate, and (3) exponential fertilization on Liriodendron tulipifera and Larix leptolepis containerized seedlings. Growth performance, nutrient uptake, and nutrient loss in leaching were measured. Height, root collar diameter, and dry weight of both species were not significantly different among treatments even though the nutrient supply of the exponential treatment was half that of the constant and three-stage treatments. Generally, nutrient losses in leached solutions were higher in constant and three-stage than the exponential treatment. Nutrient use efficiency was calculated as the ratio of the nutrient content of the seedlings to the amount of nutrient applied to the containers. The nitrogen use efficiency in the constant, three-stage, and exponential treatments was 63, 61, and 85% for yellow poplar, respectively, and 35, 30, and 53% for larch. Similar results were obtained for phosphorus and potassium. Thus, the exponential treatment had the highest nutrient use efficiency as well as the least nutrient loss. Adjusting fertilization rates can reduce soil and water contamination around the nursery without compromising growth performance, which reduces both producer’s investments and environmental impacts.

The effects of biochars on the growth of Zelkova serrata seedlings in a containerized seedling production system

ABSTRACT Biochar has been used for soil improvement in agriculture; however, there are few studies of its uses in forestry. The purpose of this study was to investigate the effects of biochar, made from diverse feedstocks on the growth and chlorophyll content of Zelkova serrata seedlings, to identify optimal feedstocks in a containerized seedling production. Five resources were used for biochar: woodchips of Pinus densiflora and Quercus acutissima; cones of Pinus koraiensis; rice husks; and crab shells. The biochar was mixed with growing medium by 20% in volume and two levels of fertilization were applied. The height and root collar diameter of Z. serrata treated with wood chips of P. densiflora and Q. acutissima and rice husk were each significantly greater than those treated with pine cones and crab shells. The biomass responses and quality indexes were similar to those of height and root collar diameter. There were no significant differences in growth between fertilization levels. This study shows that biochar made from woodchips of P. densiflora and Q. acutissima and rice husk can be substituted for growing medium by 20% in a containerized seedling production system.

Growth Performance and Photosynthesis of Two Deciduous Hardwood Species under Different Irrigation Period Treatments in a Container Nursery System

This study was conducted to investigate growth performance, photosynthesis, water use efficiency (WUE), and stomatal conductance () of container seedlings of Liriodendron tulipifera and Zelkova serrata growing under three different irrigation periods (1 time/1 day, 1 time/2 days and 1 time/3 days) for high seedling quality. The root collar diameter and height of L. tulipifera and Z. serrata seedlings were highest with 1 time/1 day irrigation, whereas they were lowest with 1 time/3 days irrigation. The two species showed low drought tolerance. As irrigation period was shortened, biomass and seedling quality index (SQI) of the two species increased. The ratio of height to root collar diameter (H/D) and the ratio of below to aboveground biomass (T/R) of the two species were lower with 1 time/3 days than at other irrigation periods. L. tulipifera and Z. serrata seedlings showed significantly higher photosynthetic capacity with 1 time/1 day irrigation. As irrigation period was shortened, of two species increased, while their WUE decreased significantly (P

Biochar effects on the seedling quality of Quercus serrata and Prunus sargentii in a containerized production system

Abstract Biochars are used to improve soil quality and crop productivity as well as to increase carbon sequestration in soil. However, it is important to identify the characteristics of biochar prior to its application because of the positive and negative effects on soil and crop productivity. The purpose of this study was to investigate the effects of charcoals on the growth and seedling quality of Quercus serrata and Prunus sargentii in a containerized seedling production system. Two of the charcoals used in our research were from oak tree; one produced at 1200u2009°C and the other at 700u2009∼u2009800u2009°C, and a bamboo charcoal produced at about 800u2009°C. Three charcoals were mixed with artificial soil (peat moss, perlite, and vermiculite with a ratio of 1:1:1 (v/v/v)), and applied commercial fertilizer at two concentrations; 0.5 and 1.0u2009g L−1. Growth parameters, such as height, root collar diameter, and dry weight, were decreased in charcoal treatments compared to control. However, charcoal treatments significantly increased the quality index of seedlings by 8.3% in Q. serrata and by 19.9% in P. sargentii. Our results suggested that charcoal can be applied to improve seedling quality in the containerized Q. serrata and P. sargentii seedling production system.

Characteristics of soil carbon and nutrient stocks across land use types in a forest region of central Korea

ABSTRACT Land use change greatly affects the carbon cycling of the Earth. Soil carbon and nutrient stock distributions were identified in the five land use types: Quercus spp. mixed forest (QM); Larix leptolepis plantation (LP); Castanea crenata plantation (CP); Malus pumila orchard (MF); and abandoned fields (AF). Carbon and nutrient concentrations in the organic horizon and the soil were significantly different according to land use type and soil depth. Carbon concentrations of the organic horizon were higher in QM than in AF, while phosphorus concentrations were higher in MF and AF by 7 times and 4 times compared to that in QM and LP, respectively. The total carbon was distributed in A horizon by 51.8% and in B horizon by 38.0%. The amount of phosphorus decreased in the order of MF > AF > CP > LP ≈ QM, showing clear differences among land use types. This research shows that soil carbon and nutrient contents are significantly different across land use types, and it suggests that the horizontal and vertical distribution properties of carbon and nutrients by land use type need to be considered to accurately predict amounts of fixed carbon and nutrients during the transition of farmland to forest.

Torrefied wood effects on the seedling quality of Zelkova serrata and Fraxinus rhynchophylla in a containerized production system

ABSTRACT Biochar can be used as a kind of soil amendment in crop production, but there are few studies on containerized seedling production in forestry. The purpose of this study was to investigate the amount of torrefied wood to mix with growing medium for Zelkova serrata and Fraxinus rhynchophylla seedling production in a containerized system. We used torrefied wood made from chips of Quercus accutissima, which was mixed with growing medium by 0%, 10%, 20%, 30%, and 40% in volume. We applied two levels of 0.5 g/L (1×) and 1.0 g/L (2×) commercial fertilizer for fertilization treatment. Generally, growth parameters such as height, root collar diameter, and dry weight were comparable among 0%, 10%, and 20% mixed ratios, but those at 30% and 40% mixed ratio were lower than other mixed ratios. The 2× fertilization significantly increased height by 29%, root collar diameter by 18%, total dry weight by 52%, and quality index by 31.4% compared to the 1× fertilization across mixed ratios. Our results suggest that torrefied wood can be substitutable for 20% of the growth medium in total volume in containerized Zelkova serrata and Fraxinus rhynchophylla seedling production systems.

Effects of cumulative fertilization pattern on growth and nutrient concentrations of Chamaecyparis obtusa seedlings

ABSTRACT The objective of this study was to investigate plant growth and nutrient uptake of Chamaecyparis obtusa seedlings with heavy fertilization treatment depending on previous fertilization experience. In a previous year, one-year-old Chamaecyparis obtusa seedlings were planted at a nursery with two levels of fertilization: the first group was fertilized with a mixed nitrogen–phosphorus (N-P) fertilizer of N 41.4 g m−2, P 18.3 g m−2 and the second group was unfertilized as a control. After one year, seedlings of similar height and root diameter were planted into 30-l pots and underwent two treatments: no fertilization for control and heavy fertilization with Basacote® 80 g pot−1. In the control, the plants’ growth exhibited no differences according to previous fertilization experience; in the case of heavily fertilized plants, seedlings which had experienced previous fertilization showed a 29% increase in height and a 63% increase in above-ground biomass production than did seedlings with no fertilization in the previous year. The biomass allocation to below-ground was low for the heavily fertilized seedlings regardless of previous treatments. N and P concentrations of the seedlings, measured at the leaf and root, were irrelevant to previous fertilization, but were higher in the heavily fertilized plants. This study suggests that previous fertilization experience at the nursery stage may reduce the stress induced by initial heavy fertilization during out-planting.