Demonstration of estimating soil moisture using the ‘hand-feel method’
After last year's success with live streaming "Crop Walks," the Ministry of Agriculture is looking forward to recording another growing season's worth of content in 2019. The Ministry of Agriculture, along with the Irrigation Crop Diversification Corporation (ICDC), will be posting these virtual field days on https://www.facebook.com/skagricult ure The focus of this year's crops walks will expand, featuring various speakers at locations across the province. This year's first Crop Walk took place on April 23 at the Canada-Saskatchewan Irrigation Diversification Centre in Outlook. The topic was soil moisture and its conservation, relevant for both dryland and irrigated producers prior to seeding. Seeding into moist soil allows your crop to germinate and establish. In the videos, we discussed methods for estimating how much moisture is available in the soil and how long it will last without a rainfall. Irrigation Agrologist Joel Peru discussed the variables relating to soil moisture including texture, crop water use (evapotranspiration) and climate. Prior to seeding, soil moisture is depleted by evaporation and evapotranspiration from weeds. Without precipitation or access to irrigation water, soil will continue to dry, making it harder for a crop to establish.
The amount of and distribution of precipitation during the growing season is important for optimal crop growth and development. Only some of the water in soil is available for plant use. Water is held to soil particles by a force called "adhesion." When the amount of water decreases to a certain point, the strength of this force is too high for a plant to extract water from the soil. This is referred to as "wilting point." If moisture drops below this level the crop will experience irreversible damage.
On the other end of the spectrum, once the soil profile is completely full after being fully drained, it’s at 100 per cent available moisture, also referred to as "field capacity." Any additional water added at field capacity is subject to surface drainage, or deep percolation into the sub soil. Joel went over a simple method of checking available soil moisture in the field by using a soil probe, hands, and a flow chart in the Irrigation Scheduling Manual, a guide produced by the ICDC.
Soil moisture conservation is a great way to avoid seeding into dry soil. Gary Kruger, Irrigation Agrologist, discussed some strategies relating to this during the crop walk. Gary went over production practices that help soil retain moisture. Some of these methods include zero tillage and pre-emergence weed control, which helps reduce losses from evaporation and crop water use from undesired plants. To view previous and upcoming Crop Walks, check out the Ministry's video collection on Facebook.