Are Cover Crops Improving Agricultural Soil Health in Oregon's High Desert?
Abstract
Central Oregon is a vibrant agricultural region comprising over 60,000 acres of irrigated crop land dedicated to high value, specialty seed crops and fresh market vegetable farms. These annual cropping systems are intensively managed and require excellent soil quality in order to be successful. Central Oregon soils are particularly vulnerable to soil degradation since they are shallow, rocky, low in organic matter, irrigated, and subject to frequent tillage. Therefore, progressive growers are seeking economic, feasible ways to improve soil health, and one such way is through cover cropping.
There is an abundance of information in academic literature and from seed companies on the merits of cover crops; however, no data exists on cover crops' effects on soil parameters in central Oregon. Growers are curious about cover crop use, but want to know that the purported soil health benefits outweigh the irrigation, seed, and lost crop opportunity costs. In response to grower interest, an over-wintering cover crop trial was planted on Sep 14, 2019 at the Central Oregon Agriculture Research and Extension Center in Madras, OR. The randomized complete block design included nine treatments: 1) Radish; 2) Turnip; 3) Spring pea; 4) Winter pea; 5) Berseem clover; 6) Hairy vetch; 7) Hairy vetch + cereal rye; 8) Crimson clover + triticale; 9) Control. Cover crop biomass samples were taken the day of termination in May 2019, and soil samples (0-5cm) were taken three weeks after termination to be analyzed for 16 physical, chemical and biological soil health indicators. In situ assessments of field indicators, including water infiltration, surface and subsurface hardness, and root density were also conducted. Cover crop biomass tended to correlate with root density, and treatments that included a cereal had the highest biomass and root density. The cover crop treatments improved soil bulk density over the control, but bulk density was not correlated to cover crop biomass or root density. The treatment with the smallest biomass production (Spring pea) generated the strongest reduction of bulk density, suggesting the stimulating effects of cover crops on soil microorganisms may be more important for the physical aspects of soil health than the magnitude of biomass produced. Additional soil analyses will be available by fall 2019.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.B44A..04S
- Keywords:
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- 0402 Agricultural systems;
- BIOGEOSCIENCES;
- 0465 Microbiology: ecology;
- physiology and genomics;
- BIOGEOSCIENCES;
- 0470 Nutrients and nutrient cycling;
- BIOGEOSCIENCES;
- 0486 Soils/pedology;
- BIOGEOSCIENCES