光合势就是植物进行光合生产的绿叶面积的积数。具体说,就是植物一生或某一生育时期的平均绿叶面积(以M~2计)乘以绿叶持续的日数,单位以M~2·日表示。一定土地面积上的植物群体的光合势,即指这一群体的平均绿叶面积的积数。如1亩小麦在整个生育期中的平均绿叶面积为2,640M~2,生长的日数为70天,则这亩小麦的光合势为2,640×70=184,800M~2·日。实际上,光合势就是将植物群体进行光合生产的功能叶(绿叶)平均面积折算为 Photosynthetic potential is the product of the number of green leaf areas that a plant produces for photosynthesis. Specifically, the average green leaf area (in M ~ 2) of a plant’s whole life or one growth period multiplied by the number of days that green leaves last, in units of M ~ 2 days. The photosynthetic potential of plant groups on a certain land area refers to the product of the average green leaf area of ​​this group. For example, if the average green leaf area of ​​1 mu of wheat during the whole growth period is 2,640M ~ 2 and the number of days of growth is 70 days, then the photosynthetic potential of this mu is 2,640 × 70 = 184,800M ~ 2 · day. In fact, photosynthetic potential is the average area of ​​functional leaves (greenery) that photosynthetic production of the plant population is converted into