Site-Specific Evaluation of Rhizobium Nodulation in Peanut

Issue: Farmers can reduce input costs by more efficiently using biologically fixed nitrogen. This reduces the need for chemical fertilizer applications.

What has been done/discovered:

Impact: Free nitrogen for your peanut crop. Does that sound like a good deal? It is if you farm peanuts in the high-yielding environment of West Texas, but unfortunately this 'free gift' can't always be assumed. Until recently many farmers have given little thought to whether the Rhizobium inoculant they apply at planting results in good nodulation of peanuts. Recent work suggests that 20 to 25% of West Texas peanut fields are undernodulated. What affects this limited degree of nodulation? Although farmer practices and mishandling of inoculant can minimize effective nodulation, soil properties and how they change across a field may have a larger impact on effective Rhizobium nodulation than first believed. Research within the State of Texas Precision Agriculture initiative is examining how soil properties such as pH, salinity, nitrogen, and other soil chemical constituents may hinder peanut yield production on farmers' fields. Early results suggest that high soil pH and the presence of caliche spots within soils restrict Rhizobium activity and their contribution of nitrogen to the peanut plant. These factors are being considered in how farmers may develop strategies to retain the potential contribution of biologically fixed nitrogen to peanut production based on soil chemical and physical properties across individual fields. Achieving the maximum contribution of free nitrogen possible through biological fixation reduces farmers' need for expensive nitrogen fertilizer inputs.

Funding Sources: State of Texas Precision Agriculture Initiative

Contact:
Calvin Trostle
Research & Extension Center - Lubbock
Texas A&M Agriculture Program
Phone: 806.746.6101
Fax: 806.746.4057
c-trostle@tamu.edu
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