Chapter 3 Multiply method Yp=E(2ΣQf(t)f(w)HI E: radiation use efficiency 2Q: sum of radiation within growing season f(t: modifying function of temperature f(w): modifying function of water balance HI: harvest index(ratio of economic yield to biomass.0.35 0.45 for wheat. 0.3-0.4 for soybean 2021/2/22 Assessment of Climate/Change ImpactsChapter 3 2021/2/22 Assessment of Climate/Change Impacts 6 of 46 Multiply method Yp=E•(Q)•f(t)•f(w)•HI =========== E: radiation use efficiency Q: sum of radiation within growing season f(t): modifying function of temperature f(w): modifying function of water balance HI: harvest index(ratio of economic yield to biomass, 0.35～0.45 for wheat, 0.3～0.4 for soybean