TITLE AGRICULTURE IN NDTRAN VERSION TWO 00000010 * EULER 00000050 * CHECK 00000060 * XREF 00000070 NOTE LIMITS TO GROWTH BY DONELLA MEADOWS ET.AL. 00000020 NOTE THIS IS THE VERSION USED IN THE TECHNICAL REPORT 00000030 NOTE LAST REVISED DECEMBER 14, L972 00000040 NOTE 00000080 NOTE LOOP 1- FOOD FROM INVESTMENT IN LAND DEVELOPMENT 00000090 NOTE 00000100 A F.K=LY.K*AL.K*LFH*(1-PL) 00000110 C LFH=.7 00000120 C PL=.1 00000130 L PAL.K=INTGRL(-LDR.JK) 00000140 N PAL=PALI 00000150 C PALI=2.3E9 00000160 L AL.K=INTGRL(LDR.JK-LER.JK-LRUI.JK) 00000170 N AL=ALI 00000180 C ALI=.9E9 00000190 A DCPH.K=TABHL(DCPHT,PAL.K/PALT,0,1,.1) 00000200 C PALT=3.2E9 00000210 T DCPHT=1E5,7400,5200,3500,2400,1500,750,300,150,75,50 00000220 R LDR.KL=TAI.K*FIALD.K/DCPH.K 00000230 A IFPC.K=CLIP(IFPC2.K,IFPC1.K,TIME.K,PYEAR) 00000240 A IFPC1.K=TABHL(IFPC1T,IOPC.K,0,1600,200) 00000250 T IFPC1T=230,480,690,850,970,1070,1150,1210,1250 00000260 A IFPC2.K=TABHL(IFPC2T,IOPC.K,0,1600,200) 00000270 T IFPC2T=230,480,690,850,970,1070,1150,1210,1250 00000280 A TAI.K=IO.K*FIOAA.K 00000290 A FIOAA.K=CLIP(FIOAA2.K,FIOAA1.K,TIME.K,PYEAR) 00000300 A FIOAA1.K=TABHL(FIT1T,FPC.K/IFPC.K,0,2.5,.5) 00000310 T FIT1T=.4,.2,.1,.025,0,0 00000320 A FIOAA2.K=TABHL(FIT2T,FPC.K/IFPC.K,0,2.5,.5) 00000330 T FIT2T=.4,.2,.1,.025,0,0 00000340 A FPC.K=F.K/POP.K 00000350 NOTE 00000360 NOTE LOOP2-- FOOD FROM INVESTMENT IN AGRICULTURAL INPUTS 00000370 NOTE 00000380 A LY.K=LYF.K*LFERT.K*LYMC.K*LYMAP.K 00000390 A LYF.K=CLIP(LYF2,LYF1,TIME.K,PYEAR) 00000400 C LYF1=1 00000410 C LYF2=1 00000420 A AIPH.K=AI.K*(1-FALM.K)/AL.K 00000430 A LYMC.K=TABHL(LYMCT,AIPH.K,0,1000,40) 00000440 T LYMCT=1,3,3.8,4.4,4.9,5.4,5.7,6.0,6.3,6.6,6.9,7.2, 00000450 X 7.4,7.6,7.8,8,8.2,8.4,8.6,8.8,9,9.2,9.4,9.6,9.8,10 00000460 A CAI.K=TAI.K*(1-FIALD.K) 00000470 A AI.K=NEW2.K 00000480 N NEW2=6.544E9 00000490 L NEW2.K=INTGRL(NEWRAT.JK) 00000500 R NEWRAT.KL=(CAI.K-NEW2.K)/ALAI.K 00000510 A ALAI.K=CLIP(ALAI2,ALAI1,TIME.K,PYEAR) 00000520 C ALAI1=2 00000530 C ALAI2=2 00000540 NOTE 00000550 NOTE APPENDIX TO LOOPS 1 & 2-- THE DECISION TO INVEST IN 00000560 NOTE LAND OR INPUTS 00000570 NOTE 00000580 A FIALD.K=TABHL(FIALDT,(MPLD.K/MPAI.K),0,2,.25) 00000590 T FIALDT=0,.05,.15,.30,.50,.70,.85,.95,1 00000600 A MPLD.K=LY.K/(DCPH.K*SD) 00000610 C SD=.07 00000620 A MPAI.K=ALAI.K*LY.K*MLYMC.K/LYMC.K 00000630 A MLYMC.K=(TABHL(MLYMCT,AIPH.K,0,600,40))(1E-3) 00000640 T MLYMCT=75,30,15,11,9,8,7,6,5,5,5,5,5,5,5 00000650 NOTE 00000660 NOTE LOOP 3 -- LAND EROSION ACCOMPANYING HIGH YIELDS 00000670 NOTE 00000680 A ALL.K=ALLN*LLMY.K 00000690 C ALLN=6000 00000700 A LLMY.K=CLIP(LLMY2.K,LLMY1.K,TIME.K,PYEAR) 00000710 A LLMY1.K=TABHL(LLMY1T,LY.K/ILF,0,9,1) 00000720 T LLMY1T=1.2,1,.63,.36,.16,.055,.04,.025,.015,.01 00000730 A LLMY2.K=TABHL(LLMY2T,LY.K/ILF,0,9,1) 00000740 T LLMY2T=1.2,1,.63,.36,.16,.055,.04,.025,.015,.01 00000750 R LER.KL=AL.K/ALL.K 00000760 NOTE 00000770 NOTE APPENDIX TO LOOP 3 -LAND FOR URBAN-INDUSTRIAL USE 00000780 NOTE 00000790 A UILPC.K=TABHL(UILPCT,IOPC.K,0,1600,200) 00000800 T UILPCT=.005,.008,.015,.025,.04,.055,.07,.08,.09 00000810 A UILR.K=UILPC.K*POP.K 00000820 R LRUI.KL=MAX(0,(UILR.K-UIL.K)/UILDT) 00000830 C UILDT=10 00000840 L UIL.K=INTGRL(LRUI.JK) 00000850 N UIL=UILI 00000860 C UILI=8.2E6 00000870 NOTE 00000880 NOTE LOOP 4-- LAND FERTILITY IMPAIRED BY LONG TERM 00000890 NOTE POLLUTING EFFECTS OF AGRICULTURAL INPUTS 00000900 NOTE 00000910 L LFERT.K=INTGRL(LFR.JK-LFD.JK) 00000920 N LFERT=LFERTI 00000930 C LFERTI=600 00000940 A LFDR.K=TABHL(LFDRT,PPOLX.K,0,30,10) 00000950 T LFDRT=0,.1,.3,.5 00000960 R LFD.KL=LFERT.K*LFDR.K 00000970 NOTE 00000980 NOTE LOOP 5--NATURAL FERTILITY MAY BE ENHANCED 00000990 NOTE 00001000 R LFR.KL=(ILF-LFERT.K)/LFRT.K 00001010 C ILF=600 00001020 A LFRT.K=TABHL(LFRTT,FALM.K,0,.10,.02) 00001030 T LFRTT=20,13,8,4,2,2 00001040 NOTE 00001050 NOTE LOOP 6 -- IMMEDIATE FOOD INCREASE FROM DISCONTINUING LAND 00001060 NOTE MAINTENANCE 00001070 A FALM.K=TABHL(FALMT,PFR.K,0,.4,1) 00001080 T FALMT=0,.04,.07,.09,.1 00001090 A FR.K=FPC.K/SFPC 00001100 C SFPC=230 00001110 A PFR.K=NEW.K 00001120 N NEW=1.1355 00001130 L NEW.K=INTGRL(PFRNEW.JK) 00001140 R PFRNEW.KL=(FR.K-NEW.K)/FSPD 00001150 C FSPD=2 00001160 NOTE 00001170 NOTE APPENDIX TO ALL LOOPS-- LAND YIELD IS DECREASED 00001180 NOTE BY AIR POLLUTION 00001190 NOTE 00001200 A LYMAP.K=CLIP(LYMAP2.K,LYMAP1.K,TIME.K,PYEAR) 00001210 A LYMAP1.K=TABHL(LY1T,IO.K/IO70,0,30,10) 00001220 T LY1T=1,1,.7,.4 00001230 A LYMAP2.K=TABHL(LY2T,IO.K/IO70,0,30,10) 00001240 T LY2T=1,1,.7,.4 00001250 C IO70=7.9E11 00001260 NOTE 00001270 NOTE EXOGENOUS INPUTS 00001280 NOTE 00001290 NOTE POPULATION GROWS EXPOMNENTIALLY AT 1.2% PER YEAR 00001300 NOTE 00001310 A POP.K=POPI*EXP(.0120*(TIME.K-1900)) 00001320 C POPI=1.65E9 00001330 NOTE 00001340 NOTE INDUSTRIAL OUTPUT GROWS EXPONENTIALLY AT 3.6% PER YEAR 00001350 NOTE 00001360 A IO.K=IOI*EXP(.036*(TIME.K-1900)) 00001370 C IOI=.67E11 00001380 A IOPC.K=IO.K/POP.K 00001390 NOTE 00001400 NOTE PERSISTENT POLLUTION GROWS EXPONENTIALLY AT 3% PER YEAR 00001410 NOTE 00001420 A PPOLX.K=PPOLXI*EXP(.30*(TIME.K-1900)) 00001430 C PPOLXI=.12 00001440 NOTE 00001450 NOTE CONTROL CARDS 00001460 NOTE 00001470 C PYEAR=1975 00001480 PARM DT=.5 00001490 PARM START=1900 00001500 PARM STOP=2100 00001510 PARM PRTPER=1 00001520 NOTE OUTPUT FOR AGRICULTURE -- FIGURE 4-69 00001530 PRINT F,AL,PL,UIL,LFERT,AI,NEW2,FR,PFR 00001540