Chapter 3 3.4 Crop growth and its modeling 3.4.1 Components of plant growth 3.4.2 Empirical models 3.4.3 Process-based models 3. 4. 4 Case studies 2021/2/22 Assessment of Climate/Change Impacts
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 1 of 46 3.4 Crop growth and its modeling 3.4.1 Components of plant growth 3.4.2 Empirical models 3.4.3 Process-based models 3.4.4 Case studies
Chapter 3 3.4.1 Components of plant growth (1) Development (2)Dry matter accumulation photosynthesis respiration water use 3)Environmental constrains(stresses) 2021/2/22 Assessment of Climate/Change Impacts 2of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 2 of 46 3.4.1 Components of plant growth (1) Development (2) Dry matter accumulation photosynthesis respiration water use (3) Environmental constrains(stresses)
Chapter 3 Crop growth models Classification Empirical models Process-based models Purpose Simulation of crop growth Crop growth management and risk assessment Component of land surface process modeling 2021/2/22 Assessment of Climate/Change Impacts 3of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 3 of 46 Crop Growth Models • Classification Empirical models Process-based models • Purpose Simulation of crop growth Crop growth management and risk assessment Component of land surface process modeling
Chapter 3 3.4.2 Empirical Crop models Larger time steps Statistical relationships Potential productivities 2021/2/22 Assessment of Climate/Change Impacts 4of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 4 of 46 3.4.2 Empirical Crop Models • Larger time steps • Statistical relationships • Potential productivities
Chaphapter 3 3.4.2 Empirical Crop models Multiply method AEZ method(Agro-Ecological Zone, FAO Miami model- npp 2021/2/22 Assessment of Climate/Change Impacts 5of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 5 of 46 3.4.2 Empirical Crop Models • Multiply method • AEZ method(Agro-Ecological Zone, FAO) • Miami model-- NPP Chap. 3
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 Impacts
Chapter 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
Chapter 3 Multiply method 黄秉维: Yp=0.93×Q p: photosynthetically potential productivity(kg/ha) Q: solar radiation (cal/cm2) coefficient:0.93=0(1-β)(1-)(1-a)×b(1-c(1-d e/(1l-6)/(1-f a: percent of PAR, 479 B: transmission of solar radiation, 5% y: percent of solar radiation absorbed by non- photosynthecally organs, 10% 2021/2/22 Assessment of Climate/Change Impacts
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 7 of 46 Multiply method 黄秉维： Yp ＝0.93×Q Yp: photosynthetically potential productivity (kg/ha) Q: solar radiation（cal/cm2） coefficient: 0.93=α(1－β)(1－γ)(1-a)×b(1－c)(1－d) ×e/(1-δ)/(1-f) α：percent of PAR, 47％ β: transmission of solar radiation, 5％ γ：percent of solar radiation absorbed by nonphotosynthecally organs, 10％
Chapter 3 Multiply method a: reflectivity, 6.5 b: energy need for per unit carbohydrates formed, 10 Enstain/ug c: 8.6Enstain/cal e: mass of per unit carbohydrates, 3X10g/ug d: percent of dry matter for respiration, 25% f: percent of dry matter for non-organic, 8% 8: percent of plant moisture 15% 2021/2/22 Assessment of Climate/Change Impacts 8of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 8 of 46 Multiply method a：reflectivity, 6.5％ b：energy need for per unit carbohydrates formed, 10 Enstain/g c：8.6Enstain/cal e: mass of per unit carbohydrates, 3×10－5g/g d: percent of dry matter for respiration, 25％ f: percent of dry matter for non-organic, 8％ δ:percent of plant moisture, 15％
Chapter 3 Multiply method-f(t Modified functions for temperature 于沪宁-赵丰收: Ft=4.301×102.t-571×104t2 2021/2/22 Assessment of Climate/Change Impacts
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 9 of 46 Multiply method—f(t) Modified functions for temperature： 于沪宁-赵丰收： Ft＝4.301×10-2 t-5.771×10-4 t 2
Chapter 3 Multiply method-f(t 李世奎: 0.027×t-0.162[6℃,21℃) 0.086×t-1.41 21C,28℃) 28℃,32℃ -0.083×t367[32℃,44℃) (to t: measured temperature to: optimal temperature 2021/2/22 Assessment of Climate/Change Impacts 10of46
Chapter 3 2021/2/22 Assessment of Climate/Change Impacts 10 of 46 Multiply method—f(t) 李世奎: 0.027×t － 0.162 [6℃，21℃) 0.086×t －1.41 [21℃，28℃） Ft 温 ＝ 1 [28℃，32℃） -0.083×t+3.67 [32℃，44℃） 0 （tt0 ) t: measured temperature t0 : optimal temperature