Spreadsheet: 42f00d99-2c28-4830-99ac-640be6ed5933
Sheet: Sheet1

Please read the VSIM User Guide prior to running the VSIM model.  The user guide provides guidelines for helping you to set up and run the VSIM model. | Unnamed: 1 | Unnamed: 2 | Unnamed: 3 | Unnamed: 4
VSIM is a PROTOTYPE spreadsheet tool for estimating the daily water balance of a vineyard block over 1 year.
VSIM is being continually developed and tested - Use at your own risk.
VSIM does not account for the effects of groundwater, soil compaction, salinity, or pests & pathogens on vine water balance
VSIM assumes a proficient working knowledge of the MS Excel spreadsheet environment
To run a VSIM simulation for a new vineyard block, save this spreadsheet as a new file and change the input parameters and climate as desired.
VSIM can be used to simulate the water balance of perrenial crops other than vineyards (other vines, orchards, etc).
VSIM is being developed with funding from NASA and the CA Dept. of Water Resources
VSIM written by [NAME], [NAME] and [NAME], NASA/Cal. State [NAME]. [NAME] ([EMAIL])
Description of Input Parameters:
Vineyard Soil Irrigation Model - VSIM-1D |  |  | Please provide a measurement or estimate of parameters in color
Parameters | Block Name | X | Parameters with * and in bold REQUIRE a measurement or estimate
Soil | % Sand (surface to rooting depth) | 36 | *Obtained from field samples or estimated based on USDA soil texture class (see table below)
Soil | % Clay  (surface to rooting depth) | 25 | *Obtained from field samples or estimated based on USDA soil texture class (see table below)
Soil | % Gravel  (surface to rooting depth) | 10 | *% of soil matrix occupied by particles larger than sand; obtained from field samples or USDA soils series descriptions
Soil | Plant Rooting Depth (m) | 1.25 | *Depth in soil which contains the majority of roots (typically <1.5 m).  Obtained from field samples or estimated based on root stock; usually equal to soil depth for shallow soils <1m deep.
Soil | Optimal midday stem water potential (bars) | 9 | Optimal or target midday stem water potential for simulated irrigation.  This parameter controls the irrigation trigger, and so will influence the amount and timing of simulated irrigation.
Cover Crop | Last Day of Cover Crop (yearday) | 150 | If there is a cover crop, this is the yearday that the cover crop dies off or is plowed under (150 = May 30; set to 0 if there is no cover crop)
Cover Crop | Cover of Cover Crop (0-1, = 0 for no CC) | 0.75 | *Fraction of ground covered by the cover crop at peak cover crop biomass, or enter 0 for no CC
Cover Crop | Fractional soil moisture to senesce cover crop | 0.6 | Fraction of total soil moisture relative to field capacity which causes cover crop to senesce (typically ~ 60%).  This parameter controls the soil moisture at which the cover crop senesces.
Vine | Peak seasonal Leaf Area Index (m2/m2) | 1.5 | *Leaf area index (LAI) = plant leaf area / ground area, and is a measure of canopy density.  [NAME] is measured or can be estimated from peak crop coefficient or % shaded area, where LAI = -ln(1-Kc)/k and [NAME] peak crop coefficient or % shaded area and k = light extinction coefficient (0.6 for vines)
Vine | Light Extinction Coefficient | 0.6 | Measured or estimated from literature values (0.6 for vines)
Vine | Degree-day sum for budbreak (Tbase = 0C) | 865 | *Calculate from local weather data; This is the average degree-day sum on date of bud break from Jan. 1, Tbase=0C (e.g. 865C for Oakville, 709C for Carneros)
Vine | Degree-day sum at peak [NAME] (Tbase = 10C) | 600 | *Calculate from local weather data; This is the average degree-day sum on date of peak LAI or peak [NAME] from bud-break, [NAME] (e.g. 370C for Carneros, 600C for Oakville)
Vine | Yearday of leaf drop & canopy senesence | 285 | Estimated based on observations, but typically by mid-autumn
Vine | Stem water potential value to initiate reduction in Kc | 5 | Stem water potential value at which [NAME] begins to be reduced due to initiation of water stress
Vine | Stem water potential value at which Kc = 0 | 12 | Stem water potential value at which [NAME] is set to 0 because of severe water stress
Vine | distance between rows (ft) | 5 | Required only to convert simulated irrigation from units of [NAME] depth to units of gallons/vine
Vine | distance between vines (ft) | 7 | Required only to convert simulated irrigation from units of [NAME] depth to units of gallons/vine
Switches | Simulate Irrigation? (0=no, 1=yes) | 1 | *Do you want the model to simulate irrigation? 0=no, 1=yes; if no, daily irrigation values can be entered in column D in Daily Water Balance sheet (daily irrigation must be in mm depth)
Switches | Alter vine [NAME] by LWP? (0=no, 1=yes) | 1 | *Do you want to adjust Kc based on soil moisture and plant water stress? 0=no, 1=yes (typically [NAME] is responsive to plant water stress)
Calculated | Soil water model A coefficient | 0.02734783768787775 | calculated soil moisture model A coefficient based on %sand & %clay for equation of Saxton et al. (1986)
Calculated | Soil water model B coefficient | -5.656316 | calculated soil moisture model B coefficient based on %sand & %clay for equation of Saxton et al. (1986)
Calculated | Soil moisture storage @ Field Capacity (mm) | 368.8801880607244 | calculated soil moisture at field capacity (-0.15 bars) based on equation of Saxton et al. (1986)
Calculated | Soil moisture storage @ Wilting Pt. ([NAME]) | 175.5618260087689 | calculated soil moisture at wilting point(-10 bars) based on equation of Saxton et al. (1986)
Calculated | Soil Moisture @ Optimal SWP (mm) | 178.8626730892692 | calculated soil moisture at the optimal soil/stem WP based on equation of Saxton et al. (1986)
Calculated | Soil Moisture @ Irrigation threshold ([NAME]) | 173.8626730892692 | calculated = optimal soil moisture - 5 mm (assuming ~10 mm per irrigation event)
Calculated | Initial soil moisture @ start of simulation (mm) | 368.8801880607244 | Initial soil moisture at start of simulation - OK to assume at field capacity on Jan. 1
Calculated | irrigation conversion (mm/m2 -> gal/vine) | 0.8584240896 | calculated based on row/vine spacing to convert simulated irrigation from units of mm to gallons/vine
Online sources of weather data:
CIMIS (California) | http://wwwcimis.water.ca.gov
Agrimet (Pacific NW) | http://www.usbr.gov/pn/agrimet
[NAME] | USDA Texture Class | %sand | %clay
 | sand | 90 | 7 | To obtain more detailed information regarding the range of USDA soil textures, see the following web site:
 | loamy sand | 82 | 10 | soil texture triangle hydraulic properties calculator - http://www.bsyse.wsu.edu/saxton/soilwater/
 | sandy loam | 65 | 11 | which is based on the following reference ([NAME] et al., 1986):
 | sandy clay loam | 60 | 27 | [NAME] et al., 1986.
 | sandy clay | 51 | 42 | Estimating generalized soil-water characteristics from texture.
 | loam | 44 | 19 | [NAME]. Soc. Amer. J. 50(4):1031-1036
 | silt loam | 23 | 16
 | clay loam | 31 | 33
 | clay | 27 | 50
 | silt | 7 | 11
 | silty clay loam | 12 | 33
 | silty clay | 10 | 45