Abstract
Nitrate concentrations in the springs and rivers in northern Florida have been increasing, and several state agencies are interested in implementing nitrogen management programs on farms to reduce N entering the groundwater. Watermelon was grown in the first season of a six-season project under various cultural and fertilization programs to investigate the relationship of N management with N leaching. Treatments were a factorial arrangement of two cultural systems (polyethylene mulch with drip-irrigated beds and unmulched, overhead irrigated beds) and three N fertilization programs [N at the extension-recommended rate, N at the commercial-watermelon-producer rate (1.5 times recommended), or N at the recommended rate with 50% of N from poultry manure]. Nitrate in the soil beneath the watermelon crop was monitored at the 2-m depth with porous-crop suction lysimeters and soil sampling. Yields were greater with the mulch/drip irrigation system compared with the unmulched/sprinkler cultural system; however, fertilization program had no effect on yield. Nitrate-N concentrations in the soil solution at the 2-m depth with all fertilizer treatments were only slightly elevated (3 to 5 mg·L -1 ) above that in the unfertilized soil (< 1.0 mg·L -1 ) early in the season when no rain fell. Later in the season, soil solution nitrate-N concentrations at the 2-m depth increased to >50 mg·L -1 with the unmulched treatment and with the greater fertilization rate. Polyethylene mulch, drip irrigation, and recommended N rate combined to maintain groundwater nitrate-N concentration below 10 mg·L -1 for most of the production season and only slightly above 10 mg·L -1 during the summer off-season when rainfall was frequent.
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Claims 7
Claim · model-written summary
Watermelon yield was greater under mulch with drip irrigation than under unmulched overhead irrigation.
- Taxon
- Watermelon
Citrullus lanatuse0 - Treatment
- mulch/drip irrigation systeme1
- Outcome
- Yieldse1
- Direction
- greatere1
- Comparator
- unmulched/sprinkler cultural systeme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e1“Yields were greater with the mulch/drip irrigation system compared with the unmulched/sprinkler cultural system”
Claim · model-written summary
The N fertilization program had no effect on watermelon yield.
- Taxon
- WatermelonCitrullus lanatuse0
- Treatment
- fertilization programe2
- Outcome
- yielde2
- Direction
- no effecte2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e2“fertilization program had no effect on yield”
Claim · model-written summary
Soil solution nitrate-N at 2 m depth was only slightly elevated, at 3 to 5 mg·L -1, above unfertilized soil early in the season.
- Taxon
- WatermelonCitrullus lanatuse0
- Treatment
- all fertilizer treatmentse4
- Outcome
- Nitrate-N concentrations in the soil solution at the 2-m depthe4
- Direction
- elevatede4
- Value
- 3 to 5 mg·L -1e4
- Qualifier
- early in the season when no rain felle4
- Comparator
- unfertilized soile4
- Setting
- northern Floridae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e3“in northern Florida”
e4“Nitrate-N concentrations in the soil solution at the 2-m depth with all fertilizer treatments were only slightly elevated (3 to 5 mg·L -1 ) above that in the unfertilized soil (< 1.0 mg·L -1 ) early in the season when no rain fell”
Claim · model-written summary
Soil solution nitrate-N at 2 m depth rose above 50 mg·L -1 later in the season under the unmulched treatment.
- Taxon
- WatermelonCitrullus lanatuse0
- Treatment
- unmulched treatmente5
- Outcome
- soil solution nitrate-N concentrations at the 2-m depthe5
- Direction
- increasede5
- Value
- >50 mg·L -1e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e5“Later in the season, soil solution nitrate-N concentrations at the 2-m depth increased to >50 mg·L -1 with the unmulched treatment and with the greater fertilization rate”
Claim · model-written summary
Soil solution nitrate-N at 2 m depth rose above 50 mg·L -1 later in the season under the greater fertilization rate.
- Taxon
- WatermelonCitrullus lanatuse0
- Treatment
- greater fertilization ratee5
- Outcome
- soil solution nitrate-N concentrations at the 2-m depthe5
- Direction
- increasede5
- Value
- >50 mg·L -1e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e5“Later in the season, soil solution nitrate-N concentrations at the 2-m depth increased to >50 mg·L -1 with the unmulched treatment and with the greater fertilization rate”
Claim · model-written summary
Polyethylene mulch, drip irrigation and the recommended N rate kept groundwater nitrate-N below 10 mg·L -1 for most of the production season.
- Taxon
- WatermelonCitrullus lanatuse0
- Treatment
- Polyethylene mulch, drip irrigation, and recommended N rate combinede6
- Outcome
- groundwater nitrate-N concentratione6
- Direction
- belowe6
- Value
- 10 mg·L -1e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e6“Polyethylene mulch, drip irrigation, and recommended N rate combined to maintain groundwater nitrate-N concentration below 10 mg·L -1 for most of the production season”
Claim · model-written summary
Groundwater nitrate-N was only slightly above 10 mg·L -1 during the summer off-season under the same combined system.
- Taxon
- WatermelonCitrullus lanatuse0
- Outcome
- groundwater nitrate-N concentratione6
- Value
- slightly above 10 mg·L -1e7
- Qualifier
- summer off-season when rainfall was frequente7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Watermelon was grown in the first season of a six-season project”
e6“Polyethylene mulch, drip irrigation, and recommended N rate combined to maintain groundwater nitrate-N concentration below 10 mg·L -1 for most of the production season”
e7“only slightly above 10 mg·L -1 during the summer off-season when rainfall was frequent”
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.