if A_DENSITY_SA is null in bln_field, calc_bulk_density throws an error about empty argument B_SOILTYPE_AGR

[BrentWHR]

Preferable behavior: bln_field throws error if A_DENSITY_SA is NULL as it should either be numeric or NA (such that it can be calculated by calc_bulk_density)

repex:

# select properties
  dt.farm <- BLN::bln_farm_hf[1,]

  # run BLN
  d1 <- bln_field(ID = dt.farm$ref_id_2022,
                  B_LU_BRP = dt.farm$B_LU_BRP,
                  B_SC_WENR = dt.farm$B_SC_WENR,
                  B_GWL_CLASS = dt.farm$B_GWL_CLASS,
                  B_SOILTYPE_AGR = dt.farm$B_SOILTYPE_AGR,
                  B_HELP_WENR = dt.farm$B_HELP_WENR,
                  B_AER_CBS = dt.farm$B_AER_CBS,
                  B_GWL_GLG = dt.farm$B_GWL_GLG,
                  B_GWL_GHG = dt.farm$B_GWL_GHG,
                  B_GWL_ZCRIT = dt.farm$B_GWL_ZCRIT,
                  B_DRAIN = dt.farm$B_DRAIN,
                  B_FERT_NORM_FR = dt.farm$B_FERT_NORM_FR,
                  B_SLOPE_DEGREE = dt.farm$B_SLOPE_DEGREE,
                  B_GWP = dt.farm$B_GWP,
                  B_AREA_DROUGHT = dt.farm$B_AREA_DROUGHT,
                  B_CT_PSW = dt.farm$B_CT_PSW,
                  B_CT_NSW = dt.farm$B_CT_NSW,
                  B_CT_PSW_MAX =0.5,
                  B_CT_NSW_MAX = 5.0,
                  B_SOMERS_BC = NA_real_,
                  B_DRAIN_SP = NA_real_,
                  B_DRAIN_WP = NA_real_,
                  A_SOM_LOI = dt.farm$A_SOM_LOI,
                  A_SOM_LOI_MLMAX = dt.farm$a_som_loi_csat_top,
                  A_CLAY_MI = dt.farm$A_CLAY_MI,
                  A_SAND_MI = dt.farm$A_SAND_MI,
                  A_SILT_MI = dt.farm$A_SILT_MI,
                  A_DENSITY_SA = dt.farm$A_DENSITY_SA, # if this column is NA_REAL_, no problem, if the column is absent in the data.table, the error is thrown
                  A_FE_OX = dt.farm$A_FE_OX,
                  A_AL_OX = dt.farm$A_AL_OX,
                  A_PH_CC = dt.farm$A_PH_CC,
                  A_N_RT = dt.farm$A_N_RT,
                  A_CN_FR = dt.farm$A_CN_FR,
                  A_S_RT = dt.farm$A_S_RT,
                  A_N_PMN = dt.farm$A_N_PMN,
                  A_P_AL = dt.farm$A_P_AL,
                  A_P_CC = dt.farm$A_P_CC,
                  A_P_WA = dt.farm$A_P_WA,
                  A_P_SG = dt.farm$A_P_SG,
                  A_CEC_CO = dt.farm$A_CEC_CO,
                  A_CA_CO_PO = dt.farm$A_CA_CO_PO,
                  A_MG_CO_PO = dt.farm$A_MG_CO_PO,
                  A_K_CO_PO = dt.farm$A_K_CO_PO,
                  A_K_CC = dt.farm$A_K_CC,
                  A_MG_CC = dt.farm$A_MG_CC,
                  A_MN_CC = dt.farm$A_MN_CC,
                  A_ZN_CC = dt.farm$A_ZN_CC,
                  A_CU_CC = dt.farm$A_CU_CC,
                  A_EW_BCS = NA,A_SC_BCS = NA,A_GS_BCS = NA,A_P_BCS = NA,A_C_BCS = NA,
                  A_RT_BCS = NA,A_RD_BCS = NA,A_SS_BCS = NA,A_CC_BCS = NA,
                  D_SA_W = dt.farm$D_SA_W,
                  D_RO_R = dt.farm$D_RO_R,
                  M_COMPOST = NA_real_,M_GREEN = NA,M_NONBARE = NA,M_EARLYCROP = NA,
                  M_SLEEPHOSE = NA,M_DRAIN = NA,M_DITCH = NA,M_UNDERSEED = NA,
                  M_LIME = NA,M_NONINVTILL = NA,M_SSPM = NA,M_SOLIDMANURE = NA,
                  M_STRAWRESIDUE = NA,M_MECHWEEDS = NA,M_PESTICIDES_DST = NA,
                  B_LSW_ID = NA_character_,LSW = NULL, output ='all',
                  runrothc = TRUE,
                  mc = FALSE)