# Plant Types

SWAT+ categorizes plants into seven different types: warm season annual legume, cold season annual legume, perennial legume, warm season annual, cold season annual, perennial and trees. The differences between the different plant types, as modeled by SWAT+, are as follows:

    1\. warm season annual legume: 

          -simulate nitrogen fixation 

          -root depth varies during growing season due to root growth 

    2\. cold season annual legume: 

           -simulate nitrogen fixation 

           -root depth varies during growing season due to root growth 

           -fall-planted land covers will go dormant when daylength is less than                                

            the threshold daylength 

    3.perennial legume: 

           -simulate nitrogen fixation 

           -root depth always equal to the maximum allowed for the plant species and soil          

           -plant goes dormant when daylength is less than the threshold daylength 

     4.warm season annual: 

           -root depth varies during growing season due to root growth

     5.cold season annual: 

           -root depth varies during growing season due to root growth 

           -fall-planted land covers will go dormant when daylength is less than the threshold 

            daylength 

      6.perennial: 

           -root depth always equal to the maximum allowed for the plant species and soil 

           -plant goes dormant when daylength is less than the threshold daylength 

       7\. trees: 

            -root depth always equal to the maximum allowed for the plant species and soil 

            -partitions new growth between leaves/needles and woody growth

            -growth in a given year will vary depending on the age of the tree relative to the 

              number of years required for the tree to full development/maturity 

            -plant goes dormant when daylength is less than the threshold daylength

Table 5:1-3: SWAT+ input variables that pertain to plant type.

| Variable Name | Definition                                                                                                                                                                                                                                                                                      | Input File |
| ------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------- |
| IDC           | Land cover/plant classification:                     1.warm season annual legume                               2.cold season annual legume                        3.perennial legume                   4.warm season annual 5.cold season annual 6.perennial                            7.trees | crop.dat   |