Spring 2004 Subsoil Moisture Survey Results
- Counties: Carroll, Calhoun, Sac, Crawford, Monona and Ida
- Date Sampled: March 31 and April 2
The ISU Extension Spring
2004 subsoil moisture survey has been completed for Carroll, Calhoun, Crawford,
Monona, Ida, Sac and Pocahontas counties. Results form this spring’s sampling
indicate that west-central IA is going into the planting season in very good
shape with a greater than average amount of moisture stored in the area’s
Most soils in west-central
IA had tremendous recharge of soil moisture following the dry conditions the
area experienced last fall. The area’s soils are holding on average 8.5 inches
of plant available water (PAW) which is 73% of capacity. This compares to only
2.6 inches of PAW last fall and 8.6 inches PAW in the spring of 2003. The
6-year spring sampling average is 7.9 inches PAW, or 93% of this year’s amount.
Areas with greater than 8
inches PAW include Carroll (9.6 inches), Ida (8.9 inches), Sac (10.2 inches) and
Pocahontas (8.1 inches) counties. Monona (6 inches PAW) and Crawford (7.5
inches PAW) Counties, although only at 51% and 65% capacity respectively, have
their best soil moisture conditions since the spring of 1999.
Areas such as Carroll, Ida
and Sac Counties which are near field capacity should use caution with tillage
and heavy equipment on the soils to prevent soil compaction. Additional
precipitation in the area could quickly waterlog the soils and the soils may
take longer to dry out. Compaction is a serious detrimental soil condition that
will affect the crop for the entire season and potentially for many years.
Areas such as
Monona County that are on the dry side can employ management strategies to
conserve soil moisture and reduce drought induced risk for the current cropping
season. Reducing tillage passes and maintaining soil surface crop residue
decreases moisture losses due to surface evaporation, keeps soil temperatures
cooler, and reduces soil compaction allowing for increased rooting capacity.
Select hybrid/varieties that are more drought tolerant and and increase the
diversity of selected hybrids/varieties and crop maturities across the farm.
Soil Profile Graphs
State-wide map and
Commentary by Elwynn Taylor