他之前是随便瞎说说，第一算浮夸风还未真正开始，他是应景随便说说，第二次已经开始浮夸，他肯定心知不对（他那么聪明的人，亩产160万斤蔬菜违背了基本物理常识），但还是应景写文章。58年底公开说自己计算有错误，找别的专家较核，第3算调整了几个参数，59年下半年第三算的内幕只有天知道了，也许跟庐山会议的风向有关？

当年钱，甚至中国的农学家应该都不懂这个理论计算吧？
from wiki:
The value of the photosynthetic efficiency is dependent on how light energy is defined. On a molecular level, the theoretical limit in efficiency is 25 percent[1] for photosynthetically active radiation (wavelengths from 400 to 700 nanometer). For actual sunlight, where only 45 percent of the light is photosynthetically active, the theoretical maximum efficiency of solar energy conversion is approximately 11 percent. In actuality, however, plants do not absorb all incoming sunlight (due to reflection, respiration requirements of photosynthesis and the need for optimal solar radiation levels) and do not convert all harvested energy into biomass, which results in an overall photosynthetic efficiency of 3 to 6 percent of total solar radiation.[1]
[edit] Typical efficiencies

Quoted values sunlight-to-biomass efficiency
Plant      Efficiency
Plants, typical     0.1%[2]

0.2–2%[3]
Typical crop plants     1–2%[2]
Sugarcane      7-8% peak