As I am reviewing last seasons Wheat agronomic reports one fact keep appearing. Good irrigation management pays in savings on nitrogen applications. Part of our service is to review the previous seasons agronomic reports with growers. But this year, the pressure of increasing fertilizer costs are causing us to scrutinize more closely the efficiency of fertility programs. Good management pays, this is nothing new. But as I look at these reports I see that growers that monitor the soil moisture and irrigate accordingly irrigate their fields less often than those who irrigate by calendar.
Whether reduction in Nitrogen efficieny is due to leaching of the fertilizer (out the tile drain) denitrification (loss of N to air in saturated soils) I cannot quantify. I can tell you that fields that have excellent production and protein (4 ton plus yields and 14% protein) generally were irrigated less often and used less nitrogen than comparable yielding fields of comparable soil texture that were irrigated more often.
Tile Cleaning Crew on the Vail Canal system near the Salton Sea (loss by leaching).
First turn off the fertilizer tank, then the head gate (just plain lost).