• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.507-518
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• 1982

Biogeochemistry of a 34-year-old red pine plantation on a Typic Udipsamment was investigated in the central sand plains of Wisconsin Biomass and net primary production were $106Mg\;ha^{-1}$ and $11.0Mg\;ha^{-1}y^{-1}$ respectively. Concentrations of elements in the vegetation were greatest in the 2- to 3-year-old needles, followed by current needles, current twigs, bole bark, live branches, dead branches, bolewood production, and bolewood. For a given tree component (excluding the current twigs), elemental concentrations were greatest in the upper one- third and least in the lower one- third of the tree. Total elements in the vegetation are ranked: N($222kg\;ha^{-1}$), Ca(217), K (85), Mg(38), S(31), and p. The soil contained from 60 to 89% of the readily available P, K, Ca, Mg, and S in the ecosystem. Whereas precipitation was the major source of N and S, weathering supplied the bulk of the Ca, Mg, P, and K. Output of a given element by leaching was less than $7kg\;ha^{-1}y^{-1}$ except for S which was $12kg\;ha^{-1}y^{-1}$ Whereas throughfall returned the greatest amounts of N, K, and S to the forest floor, litterfall accounted for the greatest returns of Ca, Mg, and P. Because of foliar leaching, net loading of all elements studied in the throughfall exceeded that of the precipitation. Ammonium in net precipitation was reduced by a factor of three within the upper 7.5cm due to uptake by fine roots.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.331-337
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• 2023

Physiological disorders in pear fruit are mainly caused by problems during the growing season, such as lack of calcium in the soil, poor drainage, low porosity, vigorous pruning, and excessive fruiting. In this study, soil physicochemical properties and leaf characteristics were analyzed in pear orchards in four regions of Korea where chlorosis symptoms occurred to determine the causes of chlorosis. The color of chlorotic leaves was diagnosed using the naked eye or SPAD and Hunter values. The soil of the chlorotic orchard had a significantly higher soil pH than that of the regular orchard. Although adequate soil depth was not significantly associated with chlorosis, combined with over-fertilization of the soil with lime, it could potentially impair plant iron uptake. Chlorotic leaves had significantly lower iron and calcium contents and significantly higher magnesium contents than those of regular leaves. Therefore, the intensive occurrence of chlorosis during secondary shoot development around June and July when it is hot and humid may be due to impaired iron and calcium absorption, leading to physiological disorders. To solve this problem, avoiding the over-application of lime and applying foliar fertilizers containing chelated iron is recommended.

• Applied Biological Chemistry
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• v.11
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• pp.173-184
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• 1969

To elucidate the effect of Amo-1618(4-hydroxyl-5-isopropyl-2-methlphenyl trimethyl ammonium chloride, 1-piperidine carboxylate) known as a kind of growth retardant, on the growth, grain yield, increasing the efficiency of nitrogen fertilizer, behavior of mineral nutritions and the rate of phosphorus utilization, this experiment was conducted pot culture method in a vinyl house. Two nitrogen level, namely, practical nitrogen level(1 N) and three times nitrogen level(3 N) was made and labelled double-calcium-superphosphate $Ca(H_2P^{32}O_4)_2.\;2H_2O)$ as a source of radioactive phosphorus(P-32) was employed $80\;{\mu}c/pot$, respectively. Rice seedlings, variety 'Suwon No. 82', was transplanted to a 1/50,000 a china pot on June 13 in 1968. For treatment, at early stage of tillering, 10,000 ppm solution of Amo-1618 was foliar sprayed only one time. The Duncan's new mutiple-range test was adopted for statistical analysis evaluating experimental data at 5% level significance. The results obtained may be summarized as follows; 1) No significant difference was found among the treatments in plant height, but in plot of Amo-1618 treatment and 3 N level, number of tillers was significantly increased than that of others. 2) Weight of 10,000 kernels and seed-setting rate was also remarkably increased in same treatment above. 3) Grain yield per pot was significantly increased in Amo-1618 and 3 N level application. This results seemed to be due to the increased the factors on the yield. 4) Contents of nitrogen and phosphorus per cent in the grain was likewise increased in Amo-1618 and 3 N application. There is, however, no difference among treatments in the content of nitrogen and phosphorus in the leaves and culms of rice plants. 5) On the other hand, the contents of potassium and magnesium, no distinctly tendeny showed among treatments. 6) The rate of phosphorus utilization was significantly increased in the plot of Amo-1618 and 3 N application.