Location 1: 2 miles west of Hooper, rainfed no-till corn after soybeans on Moody Silty Clay Loam soil (about 2.2″ of available water per foot)
August 5 – August 12
Weekly Rainfall & Crop Water Use for August 5 – August 12:
Rainfall = 0.7″
ET Reference Reading = 1.1
Corn Water Use (R4.7 beginning dent stage) = 1.21″
Soil Water Depleted at Depth (Sensor Reading) on August 12:
1 ft = 0.61″ (72)
2 ft = 0.70″ (81)
3 ft = 0.00″ (29)
Average sensor reading = 61
Total water depleted = 1.32″
Total available soil water for use before crop stress (50% of soil water depleted in top three feet) occurs: 1.99″ or about 12 days from now
Seasonal Summary (view previous weekly crop water use at NE Ag Water Mgnt Network):
June 10 – August 12 Rainfall: 11.0″
June 10 – August 12 Corn Water Use: 10.8″
Total June 10 – August 12 (Rainfall – Crop Water Use) Surplus: 0.2″
Check out the Nebraska Drought Monitor Map too, new map released on Thursdays each week. View crop water use from around Nebraska at the Nebraska Ag Water Mgnt Network.
Location 2: 5 miles east of Winslow, irrigated soybeans after corn on Belfore Silty Clay Loam soil (about 2.0″ of available water per foot)
August 5 – August 12
Weekly Rainfall & Crop Water Use for August 5 – August 12:
Rainfall = 0.0″
Irrigation = 0.8″
ET Reference Reading = 1.0
Soybean Water Use (R5 beginning seed stage) =1.1″
Soil Water Depleted at Depth (Sensor Reading) on August 12:
1 ft = 0.52″ (61)
2 ft = 0.00″ (13)
3 ft = 0.59″ (69)
Average sensor reading = 48
Total water depleted = 1.11″
Total available soil water for use before irrigation should start (trigger point to start pivot is 35% of soil water depleted in the top three feet): 1.00″ or 6 days from now, August 18.
Seasonal Summary:
June 23 – August 12 Rainfall: 5.5″
June 23 – August 12 Soybean Water Use: 9.1″
Total June 23 – August 12 (Rainfall – Crop Water Use) Deficit: 3.6″
June 23 – August 12 Irrigation: 1.3″
Location 3: 2 miles north of Arlington, irrigated no-till corn after soybeans on Belfore Silty Clay Loam Terrace soil (about 2.0″ of available water per foot)
July 29 – August 12
Weekly Rainfall & Crop Water Use for August 5 – August 12:
Rainfall = 1.6″
Irrigation =1.0″
ET Reference Reading = 0.9
Corn Water Use (R4 dough stage) = 0.99″
Soil Water Depleted at Depth (Sensor Reading) on August 12:
1 ft = 0.00″ (7)
2 ft = 0.40″ (49)
3 ft = 0.84″ (120)
Average sensor readings = 59
Total water depleted = 1.24″
Total available soil water for use before irrigation should start (trigger point to start pivot is 35% of soil water depleted in the top three feet): 1.0″ or about 6 days from now, August 18.
Seasonal Summary:
July 1 – August 12 Rainfall: 4.8″
July 1 – August 12 Corn Water Use: 8.6″
Total July 1 – August 12 (Rainfall – Crop Water Use) Deficit: 3.8″
Total July 1 – August 12 Irrigation: 2.8″
Check out the Nebraska Drought Monitor Map too, new map released on Thursdays each week. View crop water use from around Nebraska at the Nebraska Ag Water Mgnt Network.
Frequently asked questions (FAQ):
Why are we letting the soil dry down or get depleted when we have irrigation? The goal of irrigating corn and soybeans in this area is to ensure we don’t cause any water stress (50% of soil water depleted) yet provide some storage capacity for future rainfall events. Because it can take about 3 days to irrigate a field, we want to leave about 4 days worth of crop water use stored in the soil above the point of causing water stress on the crop. Therefore we can deplete about 2″ of soil moisture in the top 3 feet in a silty clay loam soil in this area before we need to start the pivot. If we apply 1″ with the pivot, that still leaves room in the soil to store another 1″ from a rainfall event in the near-term.
