石灰對於臺灣紅壤中磷肥有效性之作用（第一報）

The Effect of Lime on the Availability of Phosphorus in the Red Soil of Taiwan

曾憲鼎(H. D. Tseng) ； 張守敬(S. C. Chang)

《中華農業研究》 2卷2期 (1951/06) Pp. 1-16

https://doi.org/10.29951/JARC.195106.0001

摘要

臺灣之紅壤，酸性強，pH值在5.0以下，富鋁與鐵，有效性燐酸含量甚低，但據過去水稻栽培試驗之結果，燐肥對於水稻之效果並不顯著；紅壤對燐酸之固定作用極強，此可能爲效應微小之原因。酸性土壞上施用石灰，可減低土壤對燐酸之固定作用，因而也可增加燐肥之肥效，已爲學者所公認。木文中就中壢、桃園二地之紅壤，研究旅用石灰對於燐肥有效性之影響，其結果可歸納下列各點：－
1．中壢及桃園二地之紅壤對燐酸之固定力甚強，施用可溶性燐酸之後，幾全部被其固定，用Morgan氏抽出液所得之有效性燐酸含量極低，施用相當於1/2倍至2倍石灰需要量之石灰錢，土壤中原存之燐酸和施用之燐酸，其有效量管顯著增加。
2．據Neubauer氏幼苗試驗之結果，中壢紅壤施用相當於1/2倍與2倍石灰需要量之石灰後，小麥幼苗對燐酸之吸收率可遞增旅用量之80%。
3．據盆栽蕃茄之生育狀況，桃園及中壢二地之紅壤單施50p.p.m.之燐酸及單施相當於三倍石灰需要量之石灰均不能促長其生育，而石灰與燐酸兼施其效極佳。
4．據水稻田間栽培之結果，知水稻在二種紅壤上對於所施燐肥之效應不同：中壢紅壤上施用1.5-2.0噸／公頃之石灰或100公斤／公頃之燐酸時，均能顯著增加水稻穀藥之產量，如石灰與燐肥兼施，其效更佳，在桃園之紅壤上，施用100公斤／公頃之燐酸或1.5噸／公頃之石灰，均無效果，但施用3噸／公頃之石灰，效果極佳，以3噸之石灰與100公斤／公頃之燐酸兼施，共效應較單加3噸／公頃之石灰響所增極少。
綜上所述，石灰可以增加紅壤中天然存在之燐酸及施用之燐酸之有效性甚爲明顯；但作物對於燐酸之吸收能力及需要程度各不相同且因土壤而異，因此就特定之作物及土壤而言，土壤燐酸之不足與充分，各有不同之臨界值(Critical value)，有待於分別研究；以水稻而言，此種臨界值，尚未明悉。因此石灰與燐酸在桃園及中壢紅壤上之效應異趣，其理目前尚不能說明之。

並列摘要

The red soil occupys a large area in Taiwan. It is very acid in reaction with pH values usually below 5.0, high in iron and aluminum and low in available phosphorus. However, according to the experiments couducted in the past, it was shown that the response of rice to the phosphorus is always not very significant. This phenomena may be resulted from the phosphorus fixing power of the red soils. It has been repeatedly proved that addition of lime on the acid soil can decrease the fixing power of the soil and consequently can increase the availability of phosphorus originally remained in the soil or applied as fertilizers.
This paper deals with the experiment results of the effect of lime on the availability of phosphorus in two kinds of soils in Taiwan. The results may summarized as follows:
1. The fixation of phosphorus by the red soil in Taiwan is very strong. Only a very small portion of the applied available phosphorus can be recovered by Morgan's extractant. The extracted amount is almost doubled by the application of lime with the rate corresponding to /2 to 2 times of lime requirement of the soil.
2. According to the result of Neubauer test with wheat seeds, it is shown that addition of lime with the rate corresponding to 1/2 to 2 times of lime requirement will increase the absorbed amount of applied phosohorus-40.0% to 85.6% of that added where 50p.p.m of P2O5 was applied, and from 24.3% to 80.4% where 100p.p.m. of P20 was applied.
3. The growing condition of tomato in the pot test showed also that neither lime nor phosphorus can increase the growth of the tomato on both the Chunglee and Toayuan red soils, but lime and phosphoric combined have a significant effect.
4. The field experiments conducted on these two red soils showed that on the red soil of Chunglee either 100kg/ha of P2O5 or 1500 to 3000kg/ha of lime can increase the yield of rice but lime and phosphorus combined caused an increase much greater; on the red soil of Toayuan 1500kg/ha of P2O5 cannot increase the yield of rice but 3000kg/ha of lime or 3000kg/ha of P2O5 of lime together with 100kg/ha of P2O5 caused a significant increase.
From the above facts it is evident that lime can increase the availability of phosphorus originally remained in the soil and that applied as fertilizers. Since the feeding power and the demmand for phosphorus varies from crop to crop, it is as a matter of fact for a specified crop there is its own critical value of sufficiency or defficiency for available phosphorus. This critical value for rice on the red soils is not yet known. No explanation can therefore be given as to the different esponse of rice to lime and phosphorus in the two red soils concerned.