Date of Award

Spring 5-1-2017

Degree Type

Report

Degree Name

Master of Science (MS)

Department

Plants, Soils, and Climate

First Advisor

David J. Hole

Second Advisor

Bruce Miller

Third Advisor

Grant E. Cardon

Abstract

Organic winter wheat production in northern Utah is faced with several limitations, such as water and available soil nutrients. This study explored the possibility of adding a cover crop in the rotation to improve grain yield. There was also a replication of a large on-farm compost treatment of 18 Mg/ha (dry) for comparison.

Cover crops were selected based on a fall-planted study. Treatments included birdsfoot trefoil (Lotus corniculatus L.) with inoculants planted at 20 kg/ha, Austrian winter peas (Pisum sativum subsp. arvense) with inoculants planted at 36 kg/ha, hairy vetch (Vicia villosa) with inoculants planted at 50 kg/ha, and Deloris hard red winter wheat (Triticum aestivum L.) planted at 55 kg/ha. Morgan Dairy compost was applied at 18 Mg/ha (dry). A control plot was included and received no treatment as it would be in a regular fallow season.

There was significant biomass for the Austrian winter pea which leads to the realistic viability of incorporating a legume. However, the yield of the grain for each of the cover crop treatments was significantly lower than the grain planted without a cover crop. It is not reasonable to incorporate a cover crop in the current rotation with a full fallow season.

Interestingly, incorporating compost increased protein by as much as one percent. As expected, incorporating an additional growth cycle negatively impacted grain yield. Adding a growing cycle into the rotation decreased the yield by more than 50% in some treatments. ANOVA statistical test have been used for comparison with a p<0.05 acceptance.

The long-term effects on overall soil heath still needed to be evaluated. Rotating in a high biomass crop such as pea could lighten the economic stress involved with loss of yield for the producers. Further research is necessary to identify the best direction for organic winter wheat producers in northern Utah.

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