(20(2):47-55)EFFECTS OF CaCO3 CaSiO3 AND ORGANIC MANURE ON THE GROWTH AND YIELD OF RICE ON A FLOODED ACID LATOSOLIC SOIL

本試驗於溫室中進行，分第一期及第二期兩部份。目的為比較石灰、矽酸鈣及堆肥對強酸性紅壤種植水稻時之效果及其對土壤化學變化的影響。 除第二期作為餘效試驗外，兩期作的處理及材料、方法均相同。所用土壤為中壢茶園強酸性紅壤（質地，坋質粘壤上；PH,4.80；有機質，2.23%；活性鐵，3.50%）處理及平準為：堆肥0，0.25%；碳酸鈣0，5，10公噸/公頃；矽酸鈣0，1.5及3.0公噸/公頃。採裂區逢機區集設計，以堆肥之添加為主區，其他處理為裂區，共重複4次。每盆用土壤10公斤，肥料處理均為N、P、K各50 ppm，水稻品種為臺中65號，每盆插秧4株。土壤溶液分析，自插秧日起，每兩星期分析其PH、比電導度、Fe*、Mn* 及NH4* 才同時並記錄其株高及分蘗數，收穫後記錄其谷、藁產量，並作植物分析。 第一期為3月12日插秧，8月5日收穫，碳酸鈣顯著地提高水稻生長期中土壤的PH，略微降低水溶性Fe*、Mn* 的濃度，在不與堆肥共施時亦能增加水稻產量。其中每公頃5噸石灰之增產量谷、藁分別為27%及23%；10噸石灰則僅使谷產量增加14%，而藁產量則降低8%。 施用百分之零點二五的有機堆肥，對土壤化學變化影響雖小，卻顯著增加水稻谷、藁產量，碳酸鈣與堆肥合施時，得反效果。其中5噸石灰對產量影響雖不大，而10噸石灰則減低谷產量19%，藁產量亦因之減低。 矽酸鈣對土壤化學變化及水稻生長、產量均無明顯效應，惟與堆肥合施時似較單獨施用為佳。 第二期作為餘效試驗，各處理僅於插秧前一日施以氮、磷、鉀肥。於8月14日插秧，但本期作成熟期中因氣侯不良，日照不足，故成熟期延遲，不稔率提高，產量極低。 碳酸鈣處理中土壤PH值仍然顯著地提高，其生長期中土壤水溶性Fe* 濃度亦由未施碳酸鈣區的350-450 ppm降低至100-200 ppm之問，水溶性Mn* 濃度也隨之降低，因而促進水稻生長，提高其產量達一倍以上。 堆肥單獨處理仍較對照區產量為高，碳酸鈣與堆肥合施處理中水稻產量亦顯著提高，惟此時堆肥效用不明顯。矽酸鈣則無效。 此種土壤上（PH低，Base Saturation ％低，Active Fe含量高）施用石灰確能增產，施用量以每公頃5公噸較佳，惟效應在第二期作中（生長期前半段溫度高，土壤還原快）較第一期作更佳。堆肥單獨施用時亦能增產，其效用在第一期作中較石灰尤佳，但堆肥不能與多量石灰（5噸以上）同時施用。施矽酸鈣則無效。 Two greenhouse experiments were conducted on a straongly acid latosolic soil to compare the effects of CaCO3, CaSiO3, and organic manure on the chemical changes and the growth and yield of flooded rice. The first experiment was conducted from March to August 1969. The second was for the residual effects conducted from August 1969 to February 1970. The materials and methods used in these two experiments were the same. The soil used was a strongly acid latosolic soil from Chung-Li (Texture SiCL, PH 4.80, O.M. 2.23%, Active Fe 3.5%). The factors and levels were: organic manure, O, 0.25%; CaCO3 0.5, and 10 tons per hectare; CaSiO3, 0, 1.5, and 3.0 tons per hectare. The soil solutions were drained fortnightly and analyzed for specific Conductance, pH, Fe*, Mn*, and NH+4. Plant observations were taken every two weeks and the yield of straw and grain noted at harvest. The straw and grain were analyzed for N, P, K, Fe, Mn, and Ca. In the first experiment, CaCO3 remarkebly increased the soil pH throughout the sampling period, depressed water-soluble Fe* and Mn* after six weeks of submergence, and increased the yield of grain and straw 27% and 23% respectively in the 5 tons per hectare CaCO3 treatment, while as in the 10 tons treatment, only the grain yield was increased by 14%. 0.25% organic manure appeared to be the best treatment, though it brought about no recognizable chemical changes in the soil solution, it increased the yield of grain by 48% and straw 36%. When CaCO3 and organic manure were applied together, no remarkable effect was found in the 5 CaCO3 treatment. However, in 10 tons treatment a decreased yield of grain and straw was obtained. Probably, this was due to the fact that CaCO3 hastened the decompose of organic matter and produced high concentrations of organic acids, CO2, etc., which were toxic to the rice plant. No obvious chemical changes was brought about by CaSiO3 application, nor did it influence the growth and yield of rice. The second experiment was for the residue effects of CaCO3, CaSiO3 and manure application. The transplanting was done on August 14, but the unfavorable climate during ripening phase delayed the harvesting time and decreased the rice yield accordingly. In this experiment, CaCO3 remarkebly increased the soil PH, decreased water-soluble Fe* from 350-450 ppm. (a high Fe* concentration which was consistent through most of the sampling period.) to 100-200 ppm. Water-soluble Mn* was also decreased. Thus improved the growth of rice and remarkebly increased its yield. The effect of manure was not clear here and no response was found to CaSiO3. Lime was beneficial in this latosolic soil with low pH, low base saturation percentage but high in active Fe. The effect was better in the second crop than the first. Organic manure significantly increased the yield of rice, but it could not be used simultaneously with lime, especially high rate of lime (e.g. more than 5 tons/ha.). CaSiO3 did not benefit rice