Abstract
To determine environmental, soil, and sward effects at the initiation of cattle grazing in the spring on seasonal (forage accumulated during the grazing season) and cumulative (seasonal + initial forage mass) forage accumulation (FA), 15 commercial cow-calf producers from southern Iowa were selected by historical initial grazing date. At grazing initiation, twelve .25-m2 samples were hand-clipped from each pasture and sward heights (SH) measured with a falling plane meter (4.8 kg/m2) to determine initial forage mass. At each location, soil temperature and load bearing capacity (LBC) were measured and a soil sample was collected to measure pH and moisture, P, and K concentrations. Cumulative degree-days (base=3.85°C) and precipitation at grazing initiation were calculated from NOAA records. At the beginning of each month, at least three grazing exclosures were placed on each grazed pasture to determine monthly FA. SH in each exclosure was recorded, and a .25-m2 forage sample was hand-clipped proximate to each exclosure. At the end of each month, SH was recorded and .25-m2 hand-clipped forage samples from inside exclosures were obtained. In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801). Seasonal SH increased with earlier initial grazing dates (r2=.1996) and less accumulated degree-days (r2=.2364). Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598). Cumulative FA increased with greater soil K (r2=.4675). In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401). Cumulative and seasonal FA were correlated to degree days (r2=.3630 and.4013) and initial grazing date (r2=.3425 and .4088). Cumulative FA was correlated to soil P (r2=.3539), and seasonal FA was correlated to soil moisture (r2=.3688).
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Claims 20
Claim · model-written summary
cumulative SH increased with soil P
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
seasonal SH increased with soil P
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
cumulative SH increased with soil K
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
seasonal SH increased with soil K
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
cumulative SH increased with initial forage mass
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
seasonal SH increased with initial forage mass
Not reportedTaxon
Verbatim
e0“In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801).”
e1“southern Iowa”
Claim · model-written summary
Seasonal SH increased with earlier grazing dates.
- Outcome
- Seasonal SHe0
- Direction
- increasede0
- Value
- r2=.1996e0
- Qualifier
- earlier initial grazing datese0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Seasonal SH increased with earlier initial grazing dates (r2=.1996) and less accumulated degree-days (r2=.2364).”
e1“southern Iowa”
Claim · model-written summary
Seasonal SH increased with fewer degree-days.
- Outcome
- Seasonal SHe0
- Direction
- increasede0
- Value
- r2=.2364e0
- Qualifier
- less accumulated degree-dayse0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Seasonal SH increased with earlier initial grazing dates (r2=.1996) and less accumulated degree-days (r2=.2364).”
e1“southern Iowa”
Claim · model-written summary
Cumulative FA increased with earlier initial grazing dates.
- Outcome
- FAe0
- Direction
- increasede0
- Value
- r2=.2106e0
- Qualifier
- earlier initial grazing datese0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
seasonal FA increased with earlier initial grazing dates.
- Outcome
- FAe0
- Direction
- increasede0
- Value
- .3744e0
- Qualifier
- earlier initial grazing datese0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
Cumulative FA increased with lower soil temperatures.
- Outcome
- FAe0
- Direction
- increasede0
- Value
- r2=.2617e0
- Qualifier
- lower soil temperaturese0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
seasonal FA increased with lower soil temperatures.
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
Cumulative FA increased with greater soil P.
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
seasonal FA increased with greater soil P.
Not reportedTaxon
Verbatim
e0“Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598).”
e1“southern Iowa”
Claim · model-written summary
Cumulative FA increased with greater soil K.
- Outcome
- Cumulative FAe0
- Direction
- increasede0
- Value
- r2=.4675e0
- Qualifier
- greater soil Ke0
- Setting
- southern Iowae1
Not reportedTaxon
Verbatim
e0“Cumulative FA increased with greater soil K (r2=.4675).”
e1“southern Iowa”
Claim · model-written summary
cumulative SH correlated with soil P in quadratic regressions.
Not reportedTaxonDirection
Verbatim
e0“In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401).”
e1“southern Iowa”
Claim · model-written summary
seasonal SH correlated with soil P in quadratic regressions.
Not reportedTaxonDirection
Verbatim
e0“In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401).”
e1“southern Iowa”
Claim · model-written summary
cumulative SH correlated with soil K in quadratic regressions.
Not reportedTaxonDirection
Verbatim
e0“In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401).”
e1“southern Iowa”
Claim · model-written summary
seasonal SH correlated with soil K in quadratic regressions.
Not reportedTaxonDirection
Verbatim
e0“In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401).”
e1“southern Iowa”
Claim · model-written summary
Cumulative and seasonal FA were correlated with degree days and initial grazing date in quadratic regressions.
Not reportedTaxonDirection
Verbatim
e0“Cumulative and seasonal FA were correlated to degree days (r2=.3630 and.4013) and initial grazing date (r2=.3425 and .4088).”
e1“southern Iowa”