長期連輪作對水稻玉米產量及相關的影響

Effects of Long-term Crop Systems on Rice and Corn Yields

譚增偉(Tseng-Wei Tan) ； 陳桂暖(Kuei-Nuan Chen)

《土壤與環境》 18卷1&2期 (2015/12) Pp. 35-47

摘要

本研究探討長期連輪作對水稻與玉米產量及有關之植物相剋作用的效應，試驗田設於本所農場，屬非石灰性砂頁岩沖積土。連續20年水稻連作並無減產，與玉米輪作則對養分的吸收有正面影響而顯著提高產量，水稻產量，不論連、輪作，二期作產量恒低於一期作，平均減產18%。不論一、二期作，輪作者產量恒均高於連作者，一期作增產16%，二期作增產19%。水稻連作，不論一、二期作產量並無逐年遞增或遞減趨勢，此並不表示水稻無連作障礙，因輪作之產量恒均高於連作者，表示水稻連作障礙是存在的，但輪作並不能使二期作產量提高至一期作水準，顯見仍有其它因素造成二期作的低產。輪作之產量雖大於連作，然不論一、二期作，產量亦無逐年遞增或遞減趨勢。台農351號玉米連作則減產嚴重，連作數年即幾無產量，而輪作效果雖遠較水稻顯著，但年度間亦呈下降趨勢，唯不致有連作之幼苗嚴重枯死情形。台農351號玉米連作數年生育受阻，在改種台農1號即見生育良好，顯見玉米連作，植物相剋作用的效力及其對品種的專一性值得注意。推測，來自玉米本身根系分泌物的自毒作用是台農351號玉米連作障礙的主因。

關鍵字

耕作制度 ； 連作 ； 輪作 ； 植物相剋作用

並列摘要

The long-term field experiment bas been conducted on a noncalcareous sandstone and slate alluvial soil at the farm of TARI since 1987. One of the purposes of this experiment is to study the effect of cropping systems under applying chemical fertilizers on crop yields and allelopathy concerned. Continuously 20 years, it was concluded that no matter monoculture or rotation, the rice yield of the 2^(nd) crop was always lower than the 1^(st) crop with a 18% decrease on average. No matter the 1(st) or 2^(nd) crop, the rice yield of rotation was higher than that of continuous rice cropping permanently with a 16.3% increase for the 1^(st) crop and a 19.2% increases for the 2^(nd) crop on average. As to paddy rice continuous cropping, no matter the 1^(st) or 2^(nd) crop, the rice yields did not have the progressively increasing or decreasing tendency year by year. Otherwise, this didn't show there was no existing of barrier for continuous rice cropping. Because the yields of crop rotation is higher than those of the continuous cropping permanently, it indicated that the barrier for the paddy rice continuous cropping was existing. But the crop rotation could not make the yield of the 2^(nd) crop increase to the yield level of 1^(st) crop, obviously there were still other factors contributing to the low yield for the 2^(nd) rice crop. As to corn, the barrier of continuous corn cropping was extremely obvious. The corn yield of TN 351 showed the serious repression on the growth of the young plant after continuously for several years, with almost having no harvest. After continuous barrier on TN 351 maize hybrid for several years, another maize hybrid TN 1 has been planted to change TN 351 since 2001. Obviously, there was no inhibition on the growth of TN 1 hybrid, Allelopathy in cropping system and it's specificity on maize hybrids was worth to pay attention to. The autointoxication from root secretion of corn is possibly the main factor on the corn barrier of continuous corn cropping.

並列關鍵字

Cropping system ； Monoculture ； Rotation ； Allelopathy