# plants.plt

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The plant growth database distributed with SWAT+ includes parameters for most of the common plant species. If you need to model a land use or plant not included in the database, please feel free to contact the SWAT+ development team for assistance in determining plant parameters.
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<table><thead><tr><th width="164">Field</th><th>Description</th><th width="150">Type</th><th>Unit</th><th width="150">Default</th><th>Range</th></tr></thead><tbody><tr><td><a href="plants.plt/untitled">name</a></td><td>Name of the plant/landcover</td><td>​string</td><td>​n/a</td><td>n/a</td><td>n/a</td></tr><tr><td><a href="plants.plt/untitled-21">plnt_typ</a></td><td>Plant/landcover type</td><td>​string</td><td>n/a</td><td>n/a</td><td>n/a</td></tr><tr><td><a href="plants.plt/untitled-20">gro_trig</a></td><td>Phenology trigger</td><td>string</td><td>n/a</td><td>n/a</td><td>n/a</td></tr><tr><td><a href="plants.plt/untitled-19">nfix_co</a></td><td>Nitrogen fixation coefficient</td><td>real​</td><td>none</td><td>0.0</td><td>n/a</td></tr><tr><td><a href="plants.plt/untitled-18">days_mat</a></td><td>Days to maturity  </td><td>real</td><td>days</td><td>110.0</td><td>0.0-300.0</td></tr><tr><td><a href="plants.plt/untitled-17">bm_e</a></td><td>Biomass-energy ratio</td><td>real</td><td>(kg/ha/(MJ/m^2)</td><td>15.0</td><td>10.0-90.0</td></tr><tr><td><a href="plants.plt/untitled-16">harv_idx</a></td><td>Harvest index for optimal growth conditions</td><td>real</td><td>(kg/ha)/(kg/ha)</td><td>0.76</td><td>0.01-1.25</td></tr><tr><td><a href="plants.plt/untitled-15">lai_pot</a></td><td>Maximum potential leaf area index</td><td>real</td><td>none</td><td>5.0</td><td>0.50-10.0</td></tr><tr><td><a href="plants.plt/untitled-14">frac_hu1</a></td><td>Fraction of the growing season heat units corresponding to the 1st point on optimal leaf area development curve</td><td>real</td><td>fraction</td><td>0.05</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-13">lai_max1</a></td><td>Fraction of the maximum leaf area index corresponding to the 1st point on optimal leaf area development curve </td><td>real</td><td>fraction</td><td>0.05</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-12">frac_hu2</a></td><td>Fraction of the growing season heat units corresponding to the 2nd point on optimal leaf area development curve</td><td>real</td><td>fraction</td><td>0.40</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-11">lai_max2</a></td><td>Fraction of the maximum leaf area index corresponding to the 2nd point on optimal leaf area development curve</td><td>real</td><td>fraction</td><td>0.95</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-10">hu_lai_decl</a></td><td>Fraction of growing season when leaf area begins to decline</td><td>real</td><td>fraction</td><td>0.99</td><td>0.2-1.0</td></tr><tr><td><a href="plants.plt/untitled-9">dlai_rate</a></td><td>Exponent that governs the LAI decline rate</td><td>real</td><td>n/a</td><td>1.0</td><td></td></tr><tr><td><a href="plants.plt/untitled-8">can_ht_max</a></td><td>Maximum canopy height</td><td>real</td><td>m</td><td>6.0</td><td>0.1-20.0</td></tr><tr><td><a href="plants.plt/untitled-7">rt_dp_max</a></td><td>Maximum rooting depth</td><td>real</td><td>m</td><td>3.50</td><td>0.0-3.0</td></tr><tr><td><a href="plants.plt/untitled-6">tmp_opt</a></td><td>Optimal temperature for plant growth</td><td>real</td><td>deg c</td><td>30.0</td><td>11.0-38.0</td></tr><tr><td><a href="plants.plt/tmp_base">tmp_base</a></td><td>Minimum temperature for plant growth</td><td>real</td><td>deg c</td><td>10.0</td><td>0.0-18.0</td></tr><tr><td><a href="plants.plt/frac_n_yld">frac_n_yld</a></td><td>Normal fraction of N in yield</td><td>real</td><td>kg N/kg yield</td><td>0.0015</td><td>0.0015-0.075</td></tr><tr><td><a href="plants.plt/frac_p_yld">frac_p_yld</a></td><td>Normal fraction of P in yield</td><td>real</td><td>kg P/kg yield</td><td>0.0003</td><td>0.0015-0.0075</td></tr><tr><td><a href="plants.plt/frac_n_em">frac_n_em</a></td><td>Normal fraction of N in plant biomass at emergence</td><td>real</td><td>kg N/kg biomass</td><td>0.006</td><td>0.004-0.07</td></tr><tr><td><a href="plants.plt/frac_n_50">frac_n_50</a></td><td>Normal fraction of N in plant biomass at 50% maturity</td><td>real</td><td>kg N/kg biomass</td><td>0.002</td><td>0.002-0.05</td></tr><tr><td><a href="plants.plt/frac_n_mat">frac_n_mat</a></td><td>Normal fraction of N in plant biomass at maturity</td><td>real</td><td>kg N/kg biomass</td><td>0.0015</td><td>0.001-0.27</td></tr><tr><td><a href="plants.plt/frac_p_em">frac_p_em</a></td><td>Normal fraction pf P in plant biomass at emergence</td><td>real</td><td>kg P/kg biomass</td><td>0.0007</td><td>0.0005-0.01</td></tr><tr><td><a href="plants.plt/frac_p_50">frac_p_50</a></td><td>Normal fraction of P in plant at 50% maturity</td><td>real</td><td>kg P/kg biomass</td><td>0.0004</td><td>0.0002-0.007</td></tr><tr><td><a href="plants.plt/frac_p_mat">frac_p_mat</a></td><td>Normal fraction of P in plant at maturity</td><td>real</td><td>kg P/kg biomass</td><td>0.0003</td><td>0.0003-0.0004</td></tr><tr><td><a href="plants.plt/harv_idx_ws">harv_idx_ws</a></td><td>Harvest index that represents the lowest harvest index expected due to water stress </td><td>real</td><td>(kg/ha)/(kg/ha)</td><td>0.01</td><td>-0.2-1.1</td></tr><tr><td><a href="plants.plt/usle_c_min">usle_c_min</a></td><td>Minimum value of the USLE C factor for water erosion</td><td>real</td><td>none</td><td>0.001</td><td>0.001-0.50</td></tr><tr><td><a href="plants.plt/stcon_max">stcon_max</a></td><td>Maximum stomatal conductance</td><td>real</td><td>m/s</td><td>0.002</td><td>0.0-0.50</td></tr><tr><td><a href="plants.plt/vpd">vpd</a></td><td>Vapor pressure deficit corresponding to the 2nd point on the stomatal conductance curve</td><td>real</td><td>kPa</td><td>4.0</td><td>1.5-6.0</td></tr><tr><td><a href="plants.plt/frac_stcon">frac_stcon</a></td><td>Fraction of maximum stomatal conductance corresponding to the 2nd point on the stomatal conductance curve</td><td>read</td><td>fraction</td><td>0.75</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/ru_vpd">ru_vpd</a></td><td>Rate of decline in radiation use efficiency per unit increase in vapor pressure deficit</td><td>real</td><td>none</td><td>8.0</td><td>0.0-50.0</td></tr><tr><td><a href="plants.plt/co2_hi">co2_hi</a></td><td>Elevated CO2 atmospheric concentration corresponding the 2nd point on the radiation use efficiency curve</td><td>real</td><td>μL CO2/L air</td><td>660.0</td><td>300.0-1000.0</td></tr><tr><td><a href="plants.plt/bm_e_hi">bm_e_hi</a></td><td>Biomass-energy ratio corresponding to the 2nd point on the radiation use efficiency curve</td><td>real</td><td>(kg/ha)/(MJ/m^2)</td><td>16.0</td><td>5.0-100.0</td></tr><tr><td><a href="plants.plt/plnt_decomp">plnt_decomp</a></td><td>Plant residue decomposition coefficient</td><td>real </td><td>none</td><td>0.05</td><td>0.01-0.099</td></tr><tr><td><a href="plants.plt/lai_min">lai_min</a></td><td>Minimum LAI during  dormant period</td><td>real </td><td>m^2/m^2</td><td>0.75</td><td>0.00-0.99</td></tr><tr><td><a href="plants.plt/bm_tree_acc">bm_tree_acc</a></td><td>Fraction of biomass accumulated each year</td><td>real </td><td>fraction</td><td>0.30</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/yrs_mat">yrs_mat</a></td><td>Years to maturity</td><td>integer </td><td>years</td><td>10</td><td>0-100</td></tr><tr><td><a href="plants.plt/bm_tree_max">bm_tree_max</a></td><td>Maximum forest biomass</td><td>real</td><td>metric tons/ha</td><td>1000.0</td><td>0.0-5000.0</td></tr><tr><td><a href="plants.plt/ext_co">ext_co</a></td><td>Light extinction coefficient</td><td>real </td><td>none</td><td>0.65</td><td>0.0-2.0</td></tr><tr><td><a href="plants.plt/leaf_tov_min">leaf_tov_min</a></td><td>Perennial leaf turnover rate with minimum stress</td><td>real</td><td></td><td>12.0</td><td></td></tr><tr><td><a href="plants.plt/leaf_tov_max">leaf_tov_max</a></td><td>Perennial leaf turnover rate with maximum stress</td><td>real</td><td></td><td>3.0</td><td></td></tr><tr><td><a href="plants.plt/bm_dieoff">bm_dieoff</a></td><td>Above-ground biomass that dies off at dormancy</td><td>real</td><td>fraction</td><td>1.0</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/rt_st_beg">rt_st_beg</a></td><td>Root to shoot ratio at the beginning of the growing season</td><td>real</td><td>fraction</td><td>0.</td><td></td></tr><tr><td><a href="plants.plt/rt_st_end">rt_st_end</a></td><td>Root to shoot ratio at the end of the growing season</td><td>real</td><td>fraction</td><td>0.</td><td></td></tr><tr><td><a href="plants.plt/plnt_pop1">plnt_pop1</a></td><td>Plant population corresponding to the 1st point on the population LAI curve</td><td>real</td><td>plants/m^2</td><td>0.</td><td></td></tr><tr><td><a href="plants.plt/frac_la1">frac_lai1</a></td><td>Fraction of the maximum leaf area index corresponding to the 1st point on the leaf area development curve </td><td>real</td><td>fraction</td><td>0.</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/plnt_pop2">plnt_pop2</a></td><td>Plant population corresponding to the 2nd point on the population LAI curve</td><td>real</td><td>plants/m^2</td><td>0.0</td><td></td></tr><tr><td><a href="plants.plt/frac_lai2">frac_lai2</a></td><td>Fraction of the maximum leaf area index corresponding to the 2nd point on the leaf area development curve</td><td>real</td><td>fraction</td><td>0.0</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-5">frac_sw_gro</a></td><td>Fraction of field capacity to initiate growth of tropical plants during monsoon season </td><td>real</td><td>fraction</td><td>0.5</td><td>0.0-1.0</td></tr><tr><td><a href="plants.plt/untitled-4">aeration</a></td><td>Aeration stress factor</td><td>real</td><td></td><td>0.0</td><td></td></tr><tr><td><a href="plants.plt/untitled-3">rsd_pctcov</a></td><td>Residue factor for percent cover equation</td><td>real</td><td></td><td>0.0</td><td></td></tr><tr><td><a href="plants.plt/untitled-2">rsd_covfac</a></td><td>Residue factor for surface cover (C factor) equation</td><td>real</td><td></td><td>0.0</td><td></td></tr></tbody></table>