紅壤稻田生產力改進試驗

Study on Fertility Improvement of Latosolic Paddy in Taiwan

李子純(Tze-Shun Lee)

《中華農業研究》 31卷1期 (1982/03) Pp. 71-88

https://doi.org/10.29951/JARC.198203.0008

摘要

爲尋求提高紅壤生產力進一步改進之可能方法，以採自桃園縣楊梅鎮之低產紅壤及另一採自桃園縣新屋鄉之產量較高的紅壤母質沖積土與一採自屏東縣內埔鄉之酸性粘板岩沖積土（對照用）共三種酸性土壤在溫室盆栽水稻。處理共分三類，即：1．改良土壤物理性及肥力者（內含六處理，爲施用稻草，或穀殼，或加施矽礦滓或石灰者）。2．改進土壤微量要素狀況（內分六處理，即分別施用B，Cu，Mn，Mo，Zn及全部施用者）及3．抑制土壤鐵、鋁毒害（內分施用二氧化錳、白雲石粉及排水等）合計十七處理，重複三次。盆栽試驗自68年二期作開始，至69年二期作止，共進行三作，所用土壤未曾換新，即同一土壤連續種植水稻三作，但第三作爲餘效試驗，各處理除三要素肥料外，其他不施。
本試驗三作水稻產量顯示增加紅壤水田生產力的最佳處理爲施用稻草或穀殼，兩者中又以前者（增產16-23%）效果優於後者（增產5-35%）。當施用稻草或穀殼時如再同時施用矽礦滓或石灰，產量並不能再行提高。
植物分析結果顯示稻草或穀殼的施用所導致的最明顯差別爲植物含鉀及矽酸量的增加：施用稻草(5t/h)必使紅壤中生長的稻藳含鉀量增加19%；施用穀殼(10t/ha)使其矽酸含量增加72%。紅壤中所含鉀及矽酸本偏低，補充此二要素對水稻生長當有幫助，而統計分析結果也顯示水稻產量與稻藳中矽，鉀含量有顯著正相關關係。但由施用稻草或穀殼又再加施矽礦滓時，稻藳內鉀或矽酸含量雖更提高（矽酸含量由4.5-6.7%提高爲5.6-7.3%，仍屬偏低）水稻產量却未因之相對增加，知稻草或穀殼對水稻之效果並非完全在此。又由產量構成要素知此二處理增產之主要因素爲每穗稔實粒數的提高。則稻草或穀殼的施用除能補足此二要素外，或更能促進土壤微生物的活動，將養分貯存於土壤，待水稻生長後期再行釋出供水稻吸收利用。
又本試驗微量要素處理中，鉬的增產效果較大，雖其效果不如施用稻草或穀殼者，但相當穩定，而且鉬的施用量少，可與肥料同時施用，簡單易行，唯此項效果需進一步證實。

並列摘要

To further improve the productivity of the low-yield latosolic paddy in Taiwan, a greenhouse experiment was carried out from the 2nd crop, 1979, to the 2nd crop, the following year. Three successive rice crops were planted.
The soils used in this experiment were: Two from Taoyuan, a latosol and an alluvial soil derived from the latosolic parent material; one from Pingtung, an acidic slate alluvial soil, used as the check.
The treatments were divided into three categories; 1. Those for improving the soil physical conditions and fertility (six treatments were included in this group, i.e., the individual and combined additions of rice hull, fresh chopped rice straw, silicate slag or lime); 2. Those for improving the soil micronutrient status (six treatments including the additions of B, Cu, Mn, Mo, Zn and the combination of all); 3. Those for eliminating the toxicity of iron and aluminum (three treatments including the applications of MnO2, dolomite, and a drainage treatment-drainage rate, 1cm/day). A total of 17 treatments were compared in three replicates. Fifteen kgs of soil were used in each pot, and the pots were arranged in the greenhouse according to the randomized complete block design.
As indicated by the grain yield in these three rice crops, the best treatment for latosol was the application of rice straw (5t/ha) or hull (10t/ha), the yield increase obtained being 16-23% and 5-35%, respectively. The simultaneous application of silicate slag or lime with straw or hull did not further increase rice yield.
Plant analysis data show that the most prominent difference caused by the application of straw or hull were the increases in K and SiO2 contents of rice straw. These two elements were really low in rice plants grown on latosol, and its supply should thus be beneficial. Statistical correlation study also shows that rice yield were positively and significantly correlated with the levels of K and SiO2 in rice straw. However, from the fact that the treatments in which silicate slag were applied together with straw or hull did not further increase the rice yield in spite of the resultant further increase in the SiO2 content of plant, it may be said that the beneficial effect of the application of straw or hull in latosol was not only this. It may also be attributed to the storage of plantnutrients in soil during the early stage of plant growth probably through increased microbial activity and the release of the nutrients in later stage of growth.
Among the micronutrient treatments, that of molybdenum appeared to be the best. Though the yield increase due to Mo application was only 10-12%, far less than that due to straw or hull application, its use can still be justified because the yield effect was rather consistent, the amount needed is so small, and it can be applied together with fertillizers. Further study to confirm this result should be conducted.