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THE BERM AND MYCORRHIZA TRIAL


Overview

The Berm and Mycorrhiza Trial was developed to investigate methods of enhancing topography and of facilitating recovery of the soil's mycorrhizal communities. Two factors were considered: 1) berm "architecture" {i.e., the manner by which berms were constructed}; and 2) mycorrhizal inoculation. Two methods of berm construction were compared. The first method ("dressed" berms) approximated that used to construct berms in the HRS trial; in the second method ("rough" berms), berms were constructed using just the border maker and were not compacted. Commercially purchased mycorrhizal was applied to half the plots.

Plot size was approximately 0.2 ha (0.5 ac); each treatment was replicated five times. Each plot contained seven berms; berms were evenly-spaced on approximately 9.1 m (30 ft) centers and were oriented east to west. A seed mixture of thirteen native species was imprinted. Installation of the trial began in mid-February, 2002. Because of the late seeding date and the low rainfall, the plots were irrigated twice during the course of the experiment (21 March and 20 April, 2002). Data (percent cover and species composition) were collected from 15 quadrats (35 x 70 cm) per plot. Vegetation monitoring was conducted in mid-May 2002 (May 6, 11-12, 14, 17-20).




Table 1. Species planted in the Berm and Mycorrhiza Trial, including Family, common name, life-form, and seeding rate. Seeding rates are expressed in gross (i.e., not lbs. pure live seed) pounds per acre.

TaxonFamilyCommon NameLife-formSeeding Rate
Allenrolfea occidentalisChenopodiaceaeiodinebushshrub3.00
Atriplex polycarpaChenopodiaceaeallscale saltbushshrub3.00
Atriplex spiniferaChenopodiaceaespinescale saltbushshrub2.25
Bromus carinatusPoaceaeCalifornia bromeperennial herb4.50
Frankenia salinaFrankeniaceaealkali heathperennial herb0.75
Heliotropium curassavicumBoraginaceaeseaside heliotropeperennial herb0.75
Hemizonia pungensAsteraceaecommon spikeweedannual herb0.15
Isocoma acradeniaAsteraceaegoldenbushshrub1.00
Lasthenia californicaAsteraceaeCalifornia goldfieldsannual herb0.75
Leymus triticoidesPoaceaecreeping wild-ryeperennial herb3.00
Sporobolus airoidesPoaceaealkali sacatonperennial herb 1.50
Suaeda moquiniiChenopodiaceaebush seepweedsub-woody perennial0.75
Vulpia microstachysPoaceaesmall fescueannual herb3.00

Page created: March 1, 2005; Last updated: Dec. 20, 2005

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The Land Retirement Program is a Department of the Interior program
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