水田滿江紅固氮之肥效及抑制稻田雜草之研究

Studies on the Fertility of Azolla for Rice and the Suppression of Weeds by Azolla Mats in Rice Paddies

林錫錦(C. J. Lin)

《中華農業研究》 32卷4期 (1983/12) Pp. 348-359

https://doi.org/10.29951/JARC.198312.0006

摘要

本研究探討耐寒又耐熱滿江紅之本地種Azalla pinnaia (Da Li, Taiwan)及A. microphylla (Paraguay)當綠肥以及與水稻共作時對第一期及第二期稻作之肥效，及它們與水稻共作時滿江紅生長迅速疊覆水面對抑制稻田雜草之效果。
插秧前A. pinnata (Da Li, Taiwan)及A. microphylla (Paraguay)，養殖21天後當基肥滿江紅，其鮮重由0.75 ton/ha增加到19 ton/ha，估計在冬天養殖21天後之氮素含量爲N47kg/ha，夏天養殖21天後之氮素合量爲N39kg/ha，它們的鮮重增加25倍。供試兩品系之滿江紅綠肥養殖時在寒冷的冬天（水溫8-16℃）及炎熱的夏天（水溫25-40℃）均長得很好，顯示兩品系均很適宜爲第一期及第二期稻作之綠肥，以及與水稻共作。掩施滿江紅當基肥之處理其穀產量等於施用化學氮肥N60kg/ha之處理。
滿江紅共作後若未埋入土中，並不能供給氮肥給當作的水稻。第一期作之共作滿江紅產量比第二期作者高。插秧後接種滿江紅與水稻共作，由於滿江紅生長迅速叠覆水面，幾乎完全抑制了水田的雜草生長，因此，可不必施用殺草劑。接種滿江紅共作區之穀產量亦比不接種滿江紅區者顯著增高，而與施用殺草劑區者相近。
在單位面積叢數一定之條件下，改變行距使成10-40-10-40-cm之8雙行式及12-55-12-55cm之6雙行式之結果，抽20天共作期間內並不能增加滿江紅之產量。而就水稻產量而言，8雙行與6雙行者均較一般行距者爲低。不過8雙行式之穀產量與一般行株距者之差異不顯著。改變行株距後加大之空間在水稻生長後期會孳生雜草形成明顯的雜草帶。

並列摘要

Cold and hot-resistant strains of Azolla pinnata (Da Li, Taiwan) and A. microphylla (Paraguay) were studied for their potential for using as a source of N for the 1st and 2nd rice crops, and studied for the effect of the azolla mats on suppressing weeds in rice paddies.
Twenty-one days after both strains of A. pinnata (Da Li, Taiwan) and A. microphyllta (Parguay) were grown as a sole crop for basal green manure, the fresh azolla biomass were increased from 0.75tonfha to l9tonJha, which contained 47 and 39 kg/ha of N for the 1st and 2nd rice crops, respectively. Its fresh weight increased 25 times within 21 days of cultivation. Both strains of azolla grow very well in cold Winter (water temperature 8-16℃) and hot Summer (water temperature 25-40℃), they are suited for use as a green manure and a dual culture for both 1st and 2nd rice crops. Both strains of the fresh azolla incorporated into soils as basal green manure gave grain yield equal to the yield of applying 69kgJha of chemical N fertilizer. Without incorporation of the azolla into soils, the azolla dual culture with rice could not supply N for the concurrent rice crop.
The yield of the azolla in the dual culture with the 1st rice crop was higher than that of the 2nd rice crop. During the dual culture with rice, the rapid growth of the azolla can result in thick mats which are capable of choking out the growth of most weeds in rice paddies. Thus, the application of herbicide is not necessary. With the azolla inoculation plot, the grain yield was much higher than that of the control plot and almost equal to that of the herbicide application plot.
With the same number of rice plant maintained in the same area, the grain yields of both 8 double line (10-40-10-40cm) and 6 double line (12-55-12-55cm) were lower than that of normal 16 single line (25-25-25-25cm) treatment. However, the difference between 8 double line and 16 single line was not significantly different. The yield of azolla dual culture with rice for both double line systems were not different from that of single line system. The enlarged space of both double line systems were found to be bound in weeds after the panicle initiation stage of rice plants.