Crop indicators: maize_grain_s

Other: Crop water need: Let ET0i be the daily potential evapotranspiration [mm] for day i, and Kc(pl,ph) the crop factor per plant pl and phase ph, and s(pl,ph) and e(pl,ph) the corresponding start and end day of pl and ph then CWN(pl,ph) is the daily average of the product of Kc(pl,ph) and ET0i, for s(pl,ph)≤ i < e(pl,ph) and s(pl,IS) = climatological ons (of rs1). Water deficit: Let CWN(pl,ph)i be the daily crop water need and efftpi the daily effective precipitation (which is 0mm for daily precipitation < 6.5mm, is 75mm for daily precipitation ≥ 75mm, and else the daily precipitation RRi), then Ir(pl,ph) is the daily average of the difference of cwn and efftp per plant and phase. Water balance: Let ETi be the daily actual evapotranspiration [mm] (calculated by the daily surface latent heat flux) then WA is the daily average of the difference of the daily precipitation and ETi per plant and phase.