宜蘭低產水田土壤與性質施用矽酸鈣、稻草、重肥及暗渠排水改良效果關係之研究

Abstract

1. 宜蘭淺層土壤及排水不良稻田面積廣大，水稻患病率高，產量低落，亟待改良，乃於三星淺層剖面土壤及冬山排水不完全土壤，舉辦改良試驗。 2. 三星以施用矽酸鈣、稻草、重磷鉀及鉀穗肥等處理。冬山除此等處理外並加暗渠排水，即以谷殼為暗渠排水溝之填充材料，每距50公分設平行暗渠一條，作改良試驗。 3. 結果冬山排水不完全土壤，以谷殼作暗渠排水對不設暗渠，施用稻草者，谷增產15%（二期5.4為），不施稻草者增產13%（二期10%）。 4. 冬山施用稻草，一期增產31%（二期稻殘效21%）。故土地生產力低者，稻草有增產之效果。 5. 冬山重磷鉀鉀穗肥對普通肥料區增產11.5%（二期0.4%）。 6. 冬山施用矽酸鈣3,000kg/ha並重磷鉀肥鉀穗肥對普通肥料區增產45.7%（二期14.8%）。 7. 三星施用稻草微有減產，但差異不顯著，故土地生產力高者稻草之效果不明顯。 8. 三星施用矽酸鈣加重磷鉀鉀穗肥谷略有增產，但差異不顯著。矽酸鈣加重磷鉀鉀穗肥對重磷鉀鉀穗肥，稻草增產達5%顯著度。 9. 三星土壤深度差異大，表土厚度與谷產量，土層厚度與谷產量均成顯著之相關；谷產量與此二種土壤厚度，複相關亦極顯著，相關係數各為0.48**、0.49**及0.56**。土層厚度達65公分以上，土層加厚則不再增產。故土層厚度以65公分為佳，若小於65公分則恐難望極高之產量。 10. 在冬山水稻體含SiO2量與葉稻熱病成負相關，與谷產量成正相關，矽及排水為主要增產因素。三星一期作因特別注意防病，則SiO2之含量不構成重要增產因素。 11. 二期作三星施矽酸鈣區，不噴病藥者產量比噴病藥者為高。其他處理則反是。冬山大體上暗渠排水者，不噴藥區谷產量高於噴藥者，不排水者則反是。 12. 排水可增進水稻對SiO2之吸收，亦有促進其他元素有效性之趨勢。 13. 三星試驗地土地生產力中上，土壤含置換性Ca、Mg有效性P、K均較冬山為高。其植物體含量亦較高。因三星土壤培肥佳。故改良土壤須從分析土壤及植物，觀察土壤剖面形態，並對照作物產量諸方面通盤加以研究，而探尋水稻增產之對策。 1. Big portion of paddy field in Ilan area is low in yield due to shallow soil or poor draianage. It is an important problem for that area. 2. Field experiments were carried out on shallow paddy soil in Sansin by applying slag, straw, heavy dosage of P and K and split application of K at panicle initiation. And these treatments plus under-ground drainage were applied on imperfetly drained paddy in Tungshan. Drainage was made by digging parall ditches 50 cm apart one another,cm deep, 10 cm wide and filled with rice hull to 25 cm below soil surface then covered with soil. 3. Results showed that in imperfectly drained soil, drainage increased grain yield 15% the first crop and 5.4% in the 2nd crop when it was coupled with straw application. But 13% increase in the first crop and 10% in the 2nd crop was obtained by drainage from plots without straw application. 4. In Tungshan, 31% increase of grain yield by application of straw in first crop, and 21% increase by residual effect of straw in second crop. So that rice response to straw application on soil of low yield. 5. In Tungshan, heavy dosage of P and K and split appliction of K at panicle initiation increased grain yield by 11.5% in first crop and only 0.4% in secDnd crop. 6. In Tungshan, heavy dosage of P and K and split application of K at panicle initiation plus 3,000 kg/ha of slag (900kg/ha SiO2) increased grain yield by 45.7 % for first crop and 14.8% for second crop. 7. Rice was not possitively affected by straw in fairly productive sil by good management in Sansin field. 8. In Sansin field, heavy fertilization and slag treatments raised grain yield insignificantly but they raised straw yield of first crop at 5% level of significant. 9. Grain yield of Sansin field was highly correlated with thickness of surface soil and thickness of soil profile with coefficient of 0.48** and 0.49** respectively, but yield did pnot increase with soil depth in the portion of > 65 cm. In other words it is hardly to expect very high yield of rice in shallow soils. And no better effects might be expected by increasing depth of medium textured soil from 65 cm to deeper one. 10. In Tungshan field, slag and under-dround drainage were suitable ways for improving paddy soil. Minimizing blast disease was the main reason. Very carefull and effective control of blast made the function of slag invisible in Sansin field. 11. In Tungshan field, under-ground drainage was a better way for blast control of rice in comparison with fungicide. Slag was better than fungicide for the same purpose in both Tungshan and Sansin fields. 12. Drainage increased Si content of rice plants and there was a tendence to increase availability of other elements. in the Soil. 13. Soil in Sansin field contains more exchangeable Ca, Mg and available P and K resulting in higher content of these elemants in rice plants, and was more productive than that of Tungshan field. So that plant coupled with soil analyses may provide some information for soil amendment practices.