SARDA Ag Research - April 2022

Fertilizer Effects on Soil Moisture Changes during Crop Growing Seasons of Dryland Agriculture in Northwestern Alberta, Canada

By Kabal Singh Gill, Published in the Journal of Agricultural Science; Vol. 14, No. 3; 2022

Soil moisture in Northwestern Alberta is accumulated through snowmelt in the spring and rainfall during the growing season. Crops are generally seeded in the spring, harvested in the fall, and the land remains dormant throughout the long cold winter. Most soil moisture accumulation occurs in the spring, while many plants are inactive. It depletes during the growing season as crops and plants are actively growing and using the moisture for production. Crop production in dryland agriculture is often limited by soil moisture. Understanding the changes in soil moisture during the growing seasons can be used to improve crop production. The objectives of the current study were to assess the effects of fertilizer applications on soil moisture content (SMC) and its depletion patterns.

Changes in SMC in the 0-10, 10-20, 20-30, and 30-40 cm soil depths were monitored during the 2013-2015 growing seasons under canola and barley that were each fertilized at 0 and 100% recommended rates. The crops were grown using direct seeding methods on clay loam soil near Donnelly, Alberta.

Applying fertilizer to both barley and canola reduced the soil moisture content at all soil depths measured. The depletion of soil moisture started earlier in fertilized plots in 2013 and 2014 but not in the drier season of 2015. SMC depleted rapidly during the early and middle of the growing seasons, followed by slower or no moisture depletion once crops approached maturity. Also, SMC tended to be lower under the higher fertilized plots by the end of the growing season. The amount of SMC at the beginning of the season affected the depletion rate and fertility effects. The results also indicated that applying fertilizer increased soil water use by plants regardless of the crop type or growing season conditions.

To review the complete document please visit www.sarda.ca/peer-reviewed-articles/.