Note how yield continues to increase with N rate at very high N rates in conventional tillage, but yield in no-till tops out at about 170 lb/acre.
At most locations, the organic matter levels served to change the productivity level of the experiment, but did little to change the relative response to N within the productivity. Protein responses (not shown) also support this.
First, choose the region of the state where the field is located. When you do, the productivity of low, medium and high are defined. Next, choose the productivity for the farm from the 3 options. When this is chosen, the program is selecting the appropriate gross N rate table from a series of hidden tables working behind the scenes and hidden from view. These tables can be accessed in the new SF-712 Fertilizing Hard Red Spring Wheat and Durum circular if you want.
Next, arrow up or down to choose a wheat price that is reflective of what the grower may sell the crop for. Then select the N cost. When either of these options is changed, you can watch the change in the green box and in the sky-blue box at the bottom of the site. Next, type in the Nitrogen analysis (nitrate-N, lb/acre) from the soil test. When you do, the Nitrogen recommendation changes automatically in the sky-blue box. Next, choose the previous crop. If the crop does not contribute N to the wheat crop, select the no nitrogen supplying crop and nothing changes. If you select an annual legume, sugarbeet leaf or alfalfa/sweet clover option, the N credit is displayed in the green box directly underneath and the credit is automatically subtracted from the sky-blue box. Next choose the tillage system. If choosing conventional till, nothing changes. If choosing 5 years or less no-till, 20 lb N is added (to compensate for slow mineralization of residues during soil system change). If the field has been in CONTINUOUS no-till for over 5 years, 50 lb N is subtracted in the sky-blue box. No-till is defined as pure no-till with just a slit for the seed and also one-pass shallow (the seeding pass 3 inches or less) seeding. One pass seeding with a deep-combination tool is conventional till. Also, growers that no-till for a couple years and go back to conventional during certain crops, then no-till again go back to year one the year after conventional till. Finally, if the organic matter is greater than 5.9%, enter that number in the pink box. A credit will be displayed in the sky-blue box. No credits are offered for organic matter 5.9% or less.