Small Grain Water Use Montana Small Grain Guide

Water - Nitrogen Relationship u Studies show that without adequate Nitrogen, wheat & barley yields increase only slightly as the water is increased

Essential to convert water to grain u Select the best-adapted variety for location u Fertilize for maximum yield u Manage for high yields plant early appropriate row spacing & seeding depth u Control weeds u Control disease with variety selection & rotation u Reduce insect problems

Stored Soil Moisture u Stored soil water is the production factor most closely related to cereal crop growth and grain yield u Stored water at planting time u Precipitation during growing season

Amount of Stored Moisture Depends on: u Soil Texture u Soil Depth u Depth of Root Development u Crop ability to remove water form the soil

Rooting Characteristics u A plant’s useable water supply is limited to the water storable in the soil surrounding the crop’s root system u Dry land: match the crop and rotation to existing conditions annually u Winter grains: root system 6-9 ft u Spring grains: root system 4 1/2 ft or more u Shallow soils limit rooting depth in many Montana soils

Seasonal Water Requirements u Daily water use can vary from nothing to.3 inches for small grains

Annual Precipitation u Studies show that 3 out of every 10 years will have below normal precipitation u 2 out of 10 will be above normal

Grain Yield u Plant-Available water: available stored water in the top 4’ of soil at planting time plus precipitation between 10 days after seeding to July 31 for spring wheat u Stand establishment requires 4.6” for spring wheat and 5.3” for barley

Water Relationships u At least 5” of water required for most small grains in Montana u Barley will produce approx. 7-8 bushels per inch of water after stand establishment u Spring wheat will produce approx. 5-6 bu. Per inch of water after stand est. u Winter wheat will produce approx. 5-6 bu. Per inch of water after stand est.

Limitations u Proper fertility: crops respond better to water when fertilized u Crop/Fallow system requires the least amount of water to reach initial yield u Crop/Fallow produces the least response per inch of added water u How could this be helpful?