Ram Dalal's Rule of Thumb
    Rams "Rule of Thumb"  calculator is based on research  that relates soil water and nitate-N content measure at sowing to likely grain protein outcome.  It is only valid for  grain production regions of southern Queensland and NW NSW and  soils sampled to depths greater than 60 cm. To use this calcualtor will you need to input a reasonable reliable estimate  or measurement of available soil water (mm), soil nitrate-N (kg/ha)  to a measured soil depth.  The output is a graph that shows the likely grain protein % outcomes for a range of soil nitrate- N contents at a single soil moisture. This graph can  be used to estimate the quantity of N required to change grain protein.  To estimate the rate of extra N required to increase grain protein content location the estimate current  grain protein by :
    1. locatiing the availabe N on the x axis and follow it vertically till it intersects the blue curve.
2. from the point on the blue curve find the correspoding grain protein horizontally on the y axis.
3. locate the desired  grain protein on the y-axis and trace acroos to the bue curve horizontamly then  at the point of intesection with the bu cure trace down  verticaly to the x -axis
4.  the distance between the  new  soil nitrate-N  and the original soil nitrate-an is the  suggested increase to crop nitrogen supply to meet the new grain protein target
    Based on the data in "Dalal RC, Strong WS, Weston EJ, Cooper  JE, and Thomas, GA 1997 Prediction of grain protein in wheat and barley in a subtropical environment from available water and nitrogen in Vertisols at sowing. Australian Journal of Experimental Agriculture, 37, 351-7."
While all reasonable efforts have been made to ensure that the information provided in this Calculator can be relied on to the extent indicated, Back Paddock Company P/L can not accept responsibility for inconvenience, material loss or financial loss resulting from the use of this Calculator.
    Ram Dalal's Rule of Thumb            
    Sampling depth maximum  cm    
    Available moisture at sowing mm    
    Soil  + fertiliser N at sowing kg/ha    
    Fallow Moisture/ Available N ratio      
    Estimated grain protein  %    
    Projected  grain yield t/ha    
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