田间肥料试验持续多少年方可称为长期试验?似乎没有确切的界限.1976年7月在法国的Grignon召开了一次非常长期肥料试验及其结果的国际会议.会上提出报告的各国非常长期肥料试验的持续年限都在五十年以上.据此,凡称为长期肥料试验者,其试验持续年限至少也应在一、二十年以上.本文不将长期与非常长期加以区分,而是把超过或计划超过一、二十年以上的田间肥料试验一律称之为长期肥料试验. There seems to be no definite limit to how long a field fertilizer test can be called a long-term test, an international conference on very long-term fertilizer tests and their results was held in Grignon, France, in July 1976. The report states that very long-term fertilizer The duration of the test is more than 50 years, according to which long-term fertilizer test who, at least the duration of the trial should also be more than one or two years.This article does not distinguish between long-term and very long, but the Field fertilizers that exceed or are planned to last for more than one or two decades are collectively referred to as long-term fertilizers.