Project 1:
- Identify optimum irrigation in terms of initiation timing and application rate for soybeans in three soils: 1) deep silt loam, 2) silt loam over sand, and 3) loamy sand.
- Identify soybean irrigation trigger points for soil matric potential sensors in MOIST+.
- Identify soybean irrigation trigger points for the water balance scheduler in MOIST+.
Six irrigation treatments will be randomized and compared to a rain-fed control in 3 distinct soil types. The deep silt loam and silt over sand soils will be replicated 4 times while the sandiest soil will only have 3 replicates. Irrigation will be initiated at R1, R3 and R5 and within each timing two irrigation rates will be applied, 1.64 and 1.1 inch/week. Irrigation treatments will be adjusted for rainfall events and soil matric potential sensors will be installed to monitor soil water status.
Projct 2: This project is a continuation of work begun in 2014 and will specifically address these questions by continuing a large plot field trial to achieve the following objectives:
- Determine the latest effective growth stage to initiate irrigation to maximize yield.
- Determine the earliest effective growth stage to terminate irrigation to maximize yield.
- Determine how crop development, growth rate, and maturity are affected by timing of irrigation initiation and termination.
Research will be continued at the Milan REC under a center pivot irrigation system equipped with VRI technology. The trail will consist of 3 irrigation initiation stages (R1, R3, R5) X 1 irrigation termination stages (R6) X 1 maturity group (late IV) X 1 variety X 4 replications. All irrigation treatments will take into account natural rainfall and soil moisture will be monitored.
Also, soil samples will be collected separately from each plots after designing the filed and before assigning the treatment to make sure there is no huge differences in soil quality among the plots.