本省中部若干土壤中鉀釋放特性之研究

Potassium Release Characteristics of Some Selected Soils of Central Taiwan

林家棻(Char-Fen Lin)

《中華農業研究》 27卷4期 (1978/12) Pp. 297-308

https://doi.org/10.29951/JARC.197812.0002

摘要

為探討土壤中鉀之譯放特性，在本省中部選取20種土壤，經連續4作盆栽水稻及用熱水與四酚鈉硼(Sodium tetraphenyl boron, NaTBP)抽取，所得結果扼要如下：
用30gm土壤加30mℓ熱水，抽取時間從15、30、60、120、180至240分鐘，所抽出鉀量與抽出時間之對數成極顯著之直線迴歸，其抽出速率之變異從8.62~50.01 ppm K/1og(min)。另從複迴歸方程式中顯示用熱水抽出之K抽出速率與土壤中置換性鉀成正比，而與土壤pH或游離鐵含量成反比。
用1.0gm土壤加NaTPB液，抽取時間從15、120、240、480至960分鐘，所抽出的鉀量與抽出時間成極顯著的直線迴歸，其變異範圍從0.4~3.09 ppm K/min。又從複迴歸方程式顯示以NaTPB所得之K抽出速率與土壤中非置換性鉀含量成正比，而與土壤pH成反比。
同一土壤，連續盆栽4作水稻，其K總吸取量之變異範圍，在無肥處理之下為405~1176mg K/5.0kg Soi1，-K處理者為414~2498mg K/5.0kg Soi1，+K處理者為1537~3436mg K/5.0kg Soil，從-K處理4作水稻總吸取量及栽培後，土壤中置換性鉀普遍劇降，顯示水稻生長期中，必然利用土壤中部分的非置換性鉀。
水稻之K吸取速率與土壤中K釋放速率有著顯著的關係。但從各溶劑所抽出的K有效指數，以估計土壤中K供應情形時，仍以Mehlich氏鉀與水稻吸取量之相關係數最高，其法亦最便捷。

並列摘要

To evaluate K release, twenty soils from central Taiwan were intensively cropped with rice in pots, and soil K was extracted with hot water as well as sodium tetraphnyl-boron (NaTPB) for varying periods. When 30-gm soil samples were equilibrated with 30 ml hot water for 15, 30, 60, 120, 180, and 240 min., K extracted with hot water was linearly correlated with the logarithm of time from 15 to 240 min. Rate of K release varied from 8.62 to 50.01 ppm K/log (min.). Multiple regression equation between K release and other soil factors indicated that the rate of K release with hot water was positively proportional to the amount of exchangeable K present in the soil, but negatively to the soil pH or to the content of free iron oxides.
When 1-gm soil samples were equilibrated with solution containing NaTPB for 15, 120, 240, 480, and 960 min. Rate of K release varied from 0.4 to 3.09 ppm K/min. It was also found that the rate of K release was positively correlated with the content of non-exchangeable K (extracted by boiling N nitric acid) and negatively with soil pH as shown in a multiple regression equation.
Amounts of plant available K, as determined from cumulative K uptake by four successive croppings of rice plant varied from 405 to 1176, 414-2498, and 1537-3436 mg K/5.0 kg soil for the none, -K and +K treatments, respectively. The rate of K uptake was fairly well correlated with the rate of K release from the soil extracted either with hot water or with NaTPB. However, for the purpose of soil testing, the K values obtained by Mehlich procedure may adequately predicate the K supplying power of the soil.