Avoid having TRNU .EQ. 0.0 statements

[lpmorenoc]

The following subroutines should be modified so it is TRNU > 0.0, estimate NUF and if not then RETURN:
Code File Line Column
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\ALOHA-Pineapple\Aloha_NUPTAK.for 241 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\CERES-IXIM-Maize\MZ_IX_NUPTAK.for 321 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\CERES-Maize\MZ_NUPTAK.for 225 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\CERES-Millet\ML_NUPTAK.for 195 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\CERES-Sorghum\SG_NUPTAK.for 195 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\CERES-Sugarbeet\BS_NUPTAK.for 189 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\OilCrop-Sunflower\SU_NUPTAK.for 252 14
IF (TRNU .EQ. 0.0) RETURN C:\dssat-csm-os\Plant\SUBSTOR-Potato\PT_NUPTAK.for 358 14