Relations Between Composition of Exchangeable Bases of Soil and Growth of Tea Plant

Transcription

1 Relations Between omposition of xchangeable Bases of Soil and Gwth of Tea Plant By KNJIRO IKGAYA Laboratory of Soil and Manure, p Division, Tea Research Station T he adequate ph (II2) in the soil for the gwth of tea plant is said to be...> However, since the climate of Japan is mild with much rainfall, there is much leaching of bases of soil and the soil is under the conditions which would acidify it. Besides, much nitgen fertilizer is applied to tea field so that the tea soil is apt to be stngly acidic. Therefore, in order to increase the pductivity of tea soil, it is necessary to lime the soil. It is not apppriate, however, to determine the necessity of, or degree of, liming on the basis of pli of the soil alone. It has been found fm the investigation carried on tea soil that it is more apppriate to determine it on the basis of exchangeable bases of soi 1. >. 3 > onsequently, since 197 research on the changeable bases of soil and the gwth of tea plant > was investigated and that was finished in Its result has been applied fo r the impvement of tea soil. Relationship between composition of exchangeable bases of soil and gwth of tea plant in the actual tea field Tea soil in Japan can be ughly classified into two types organic acid soil and mineral acid soi l. The former is derived fm volcanic ash soil and "Kuboku" ( di luvium), and the latter fm diluvium, tertiary, mesozoic strata, paleozic formation and igneous, reel yellowish in color. They are distributed in about ratio. Tables 1 and 2 show the result of investigation carried out on the tea fie lds, showing good and poor gwth of tea plant, bases on Soil Table 1. Soil reaction and composition of exchangeable bases in hig h pductive tea soil Hori;1,on ph ation exchange. 11, K! able capacity xcha. bases saturalion a I< Mg Base saturation I me Jt 2..9t 43. I qt Red yellowish soil : "Kuboku" soil (organic) Volcanic ash soil (organic) l I 2 4.2, l l I l

2 Table 2. Soil reaction and composition of exchangeable bases in low pductive tea soils ph _ ation exchange xchan. bases saturation Base Soil Horizon saturation H 2 Kl able apacity a K Mg Red yellowish soil I "Kuboku" soil (organic) Volcanic ash soil me 9.89b 2. 9% l.69; ; l the composition of exchangeable bases of the soil, red yellowish one, "Kuboku" and volcanic ash. As the tables indicate, in the low pductive tea soil, saturation of exchangeable a, K and Mg is comparatively lower compared with high pductive tea soil. Furthermore, in the first layer of volcanic ash soil of low pductive tea soi l, saturation of a is higher than that of hi gh pductive tea soil, but saturation of Mg is extremely low, which would accoun t for the excellent gwth of tea plant. Up to the third layer, saturation of a in high pductive tea soil is 244%, and although saturation of Mg varies, depending ( a. 7. <!) Fig /) a. 1/) 4 t,:,, t c; ;;, 3 ffl 2 t.x ::, 1: Saturation degree upon the layers, it is appximately % on the average. Relative relationship is observed between ph (H,) and saturation of bases in red yellowish soil, but no definite relationship between them can be recognized in organic soil. This is considered to be due to the big buffer action of soil. Since the above results were obtained after the investigation made on the actual tea soil, the following pot experiments were conducted as to the relationship between the composition of exchangeable bases of soil and gwth of tea plant. K. saturation degree D K 1.29o J K % m K 1% ; t No.Tr.% of ffects of saturation degree of and potassium on the gwth of tea seedlings in red yellowish soil.

3 J ARQ Vol., No. 3, 197 Saturation of exchangeable a, K and Mg and gwth of tea plant Pot experiments were callied out to find out the relationship between saturation of 1. r. K. saturation J K tr. 1 G K (.!). 1/1 K1 <1&.. 1/1 O,.:; :, ;;:., :. r Qi. r " : > "...!!! :" Qi. :: " r,. " : I 2.::: r n No.Tr Fig. 2. ffects of saturation degree of exchangeable calcium and potassium on the gwth of tea seedlings in "Kuboku" soil. Q(J exchangeable a, K and gwth of tea plant, with red yllowish soil and organic soil ("Kuboku"), keeping the saturation of exchangeable Mg of the soil at %. Saturation of a was varied fm nontreated to 2%, %, 7 %, 1% and 12%. Saturation of K was varied fm nontreated to % and 1%. The result is shown in Figs. 1 and 2, indicating dry matter of tops per pot. These figures indicate that for both types of soil, it was found that when saturation of a was 2%, saturation of K, 1% and saturation of Mg, %, the gwth of tea plant was the best. Next, pot experiments were conducted to examine the relationship between saturation of a and Mg, > with red yellowish soil. The result is shown in Fig. 3, indicating the dry matter of tops. It was found that when a saturation was 4.7% and 2%, the best gwth was obtained with 2% Mg saturation. When saturation of Mg was increased to %, gwth clearly deteriorated. At % a saturation, gwth is best when Mg saturation is up to %, but above that saturation, gwth was obstructed. Fm the above results, the composition of exchangeable bases of soil apppriate to the gwth of tea plant was observed when the saturation of (a+ i\ig) was 2. (.!) 4 3 1/1. 2 1/1 2 Qi ;;: :;; ;: ; :; : tr ; _.;.,.., :.., ;., ;:. 2 a. saturation J a 4.7"/, a 2",, l2zj a (/",: % Satura tion degree of exchangeable magnesium Fig. 3. ffects of saturation degree of and magnesium on the gwth of tea seedl ings in red yellowish soil.

4 41 %, keeping the saturation of Mg to % as the minimum, and that of K, 1%. ffect of a saturation on inorganic content of new, mature, old leaves and young stem Pot experiments were conducted, using red yellowish soil to examine the effect of a saturation on the inorganic content of new, mature and old leaves and young stem, keeping a saturation at 2.3%, 2%, % and 1%, and K and Mg saturation at % respectively. 6 > It was found, as indicated in Fig. 4, that x New leaf "Young s tem Fig. shows, a content in old leaf increased with the increased saturation of a. Fig. 6 % O 1. i 1. ><New leaf "Young stem. (.) X % Fig.. ffect of saturation degree of exchangeable calcium on the calcium content in old, mature, new leaves and young stem of tea plant. Fig % ffect of saturation degree of exchangeable calcium on the magnesium content in old, mature, new leaves and young stem of tea plant. when a saturation was up to 2.32%, Mg content was found mostly in old leaf, decreasing in new leaf, mature leaf and young stem, in that order. However, when a saturation exceeded %, it was found principally in new leaf and decreasing in mature leaf, old leaf and young stem, in that order, i.e., it was indicated that when a is deficient, a great deal of Mg is absorbed in old leaf, to take the place of a. However, in stngly acidic soil, both a and Mg are lacking, so that Mg deficiency most stngly appears in old leaf. Most a, Mn and Al content was found in old leaf and decreasing in mature leaf, new leaf and young stem as maturity decreased. As %.3,._.2 r:.2 O.1 ::l x New leaf " Young stem 1% Fig. 6. ffect of saturation degree of exchangeable calcium on the manganese content in old, mature, new leaves and young stem of tea plant. indicates that Mn content rapidly decreased when a saturation exceeded %. Al content showed the same tendency as that of Mn. Fm the above results, it was surmised that the reason why the gwth of tea plant becomes poor when a saturation exceeds %

5 42 is because of excessive a content and deficiency in Mn and Al in old leaf. Present situation of application of base to tea soil As stated before, tea soil in Japan is extremely acidic and lacking in a and Mg. Therefore, bearing the above results in mind, dolomite is often applied to the tea soil so that it would have the best composition of bases. In tea plantation, it is impossible to apply dolomite all over the field so that it is applied only by badcasting between the ws of tea. As a result, the application of dolomite is limited to about 1/ of the total area, and to inorganic soil, 61 kg per 1 are and to organic soil, 12 kg per 1 are are applied at the beginning or the middle of September every year. However, before applying dolomite, though check is made on the reaction and composition of bases so that there will be no over liming. JARQ Vol., No. 3, 197 Reference!;! 1) Kawashima, R.: Relation between the reaction and calcium content of soil and plant gwth, Part 12. Tea seedling. P. Sci. Soil Manure, Jav<m 12, (1938). 2)" Kawai, S., Ishigaki, K. and Ikegaya, K.: Relation between the degree of calcium, potassium and magnesium saturation of soil and gwth of tea plant, Part 1. On the soil derived fm the Fuji volcanic ash soil. Stildy of Tea, No. 17, 4147 (197). 3) Kawai, S., Ishigaki, K. and Ikegaya, K.: Soil survey on the tea soils of lwatahara, Shizuoka Prefecture. Stiidy of Tea, No. 2, 7783 (199). 4) Kawai, S. and Ikegaya, K.: Relation between the composition of exchangeable bases of soil and the gwth of tea plant. Biill. Tea Resecvrch Station, Ministry of Agriculture and Forestry, No. 1, (1962). ) Kawai, S. and Ikegaya, K.: Relation between the saturation degree of, potassium and magnesium of soil and the gwth of tea plant, Part i. On pot experiment with the red yellowish soil of Makinohara Plateau. Study of lea, No. 22, 819 (196). 6) Kawai, S. and Ikegaya, K.: ibid. Part 4. ffect of saturation degree of exchangeable calcium of soil on the mineral contents of new leaf, mature leaf, old leaf and young stem of the tea plant. Stildy of Te<i, No. 24, 3438 (1961).