Abstract
Abstract Experiments were conducted to determine if crop residues, common to eastern Washington, were likely to cause phytotoxicity problems with no‐till planting of winter wheat ( Triticum aestivum L.) The possible role of microorganisms was assessed also. Mats (5 to 8 cm thick) of lentil ( Lens culinaris Medic.), pea ( Pisum sativum L.), wheat, barley ( Hordeum vulgare L.), and bluegrass ( Poa pratensis L.) residues were spread over bare soil in Sept. 1975. Water extracts of the residues and soil beneath them were bioassayed weekly for wheat‐seedling phytotoxins, and the residues were plated biweekly to determine the numbers of fungi, bacteria, and pseudomonads from Sept. 1975 through May 1976. All residues produced wheat‐seedling root inhibitors, but only after conditions became favorable for microbial growth. Toxin production from these straws was irregular and was generally preceded by wet weather with air temperatures above freezing but below 15°C. Lentil‐ and pea‐straw extracts were most toxic to wheat seedlings in the fall and early winter, causing up to 90% root growth inhibition but little or no inhibition later. Wheat‐ and barley‐straw extracts were less inhibitory. However, these residues intermittently produced seedling inhibitors in the fall, late winter, and until late April when the straw dried. Bluegrass straw extracts showed toxic substances primarily in late winter and early spring. The delayed toxin production could explain why fall‐killed bluegrass sod was detrimental to no‐till seeded spring wheat, while spring‐killed no‐till seeded sod produced excellent wheat yields. The toxin(s) extracted were apparently different from those described by other researchers, since they (i) inhibited root growth only, (ii) were produced at lower temperatures, (iii) were produced cyclically over longtime periods, (iv) were stable when autoclaved, and (v) were not soluble in the organic solvents tested.
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Claims 7
Claim · model-written summary
All residues produced wheat seedling root inhibitors after microbial growth became favorable.
- Taxon
- winter wheat
Triticum aestivumt0 - Outcome
- wheat‐seedling root inhibitorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All residues produced wheat‐seedling root inhibitors, but only after conditions became favorable for microbial growth”
t0“winter wheat”
Claim · model-written summary
Toxin production was irregular and preceded by wet weather below 15°C.
- Taxon
- winter wheatTriticum aestivumt0
- Outcome
- Toxin productione0
- Qualifier
- wet weather with air temperatures above freezing but below 15°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Toxin production from these straws was irregular and was generally preceded by wet weather with air temperatures above freezing but below 15°C”
t0“winter wheat”
Claim · model-written summary
Lentil straw extracts caused up to 90% wheat root growth inhibition in fall and early winter.
- Taxon
- wheatTriticum aestivume0
- Treatment
- Lentil‐ and pea‐straw extractse0
- Outcome
- root growth inhibitione0
- Direction
- inhibitione0
- Value
- 90%e0
- Qualifier
- fall and early wintere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lentil‐ and pea‐straw extracts were most toxic to wheat seedlings in the fall and early winter, causing up to 90% root growth inhibition but little or no inhibition later”
Claim · model-written summary
Wheat and barley straw extracts were less inhibitory.
- Taxon
- wheatTriticum aestivume0
- Treatment
- Wheat‐ and barley‐straw extractse0
- Outcome
- inhibitorye0
- Direction
- lesse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wheat‐ and barley‐straw extracts were less inhibitory”
Claim · model-written summary
Bluegrass straw extracts were toxic mainly in late winter and early spring.
- Taxon
- winter wheatTriticum aestivumt0
- Outcome
- toxic substancese0
- Qualifier
- late winter and early springe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Bluegrass straw extracts showed toxic substances primarily in late winter and early spring”
t0“winter wheat”
Claim · model-written summary
Fall killed bluegrass sod was detrimental to no till spring wheat, whereas spring killed sod yielded well.
- Taxon
- spring wheatTriticum aestivume0
- Outcome
- wheat yieldse0
- Comparator
- spring‐killed no‐till seeded sode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fall‐killed bluegrass sod was detrimental to no‐till seeded spring wheat, while spring‐killed no‐till seeded sod produced excellent wheat yields”
Claim · model-written summary
Extracted toxins inhibited root growth only and had several distinguishing properties.
- Taxon
- winter wheatTriticum aestivumt0
- Outcome
- root growthe0
- Direction
- inhibitede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“they (i) inhibited root growth only, (ii) were produced at lower temperatures, (iii) were produced cyclically over longtime periods, (iv) were stable when autoclaved, and (v) were not soluble in the organic solvents tested”
t0“winter wheat”
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botanical · disease · Triticum aestivum (wheat)Positive and negative results
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