Abstract
Forage sorghum (Sorghum bicolor (L.) Moench) is an important annual forage crop but prone to high nitrate concentration which can cause toxicity when fed to cattle (Bos taurus and Bos indicus). Two field experiments were conducted over six site-years across Kansas to determine the optimum nitrogen (N) rate for no-till forage sorghum dry matter (DM) yield and investigate the effect of N fertilization on sorghum forage nitrate content. A quadratic model described the relationship between sorghum DM and N rate across the combined site-years. Maximum DM yield of 6530 kg ha−1 was produced with N application rate of 100 kg N ha−1. The economic optimum N rate ranged from 55 to 70 kg N ha−1 depending on sorghum hay price and N fertilizer costs. Crude protein concentration increased with N fertilizer application but N rates beyond 70 kg N ha−1 resulted in forage nitrate concentrations greater than safe limit of 3000 mg kg−1. Nitrogen uptake increased with N fertilizer application but nitrogen use efficiency and N recovery decreased with increasing N fertilizer rates. In conclusion, forage sorghum required 55–70 kg N ha−1 to produce an economic optimum DM yields with safe nitrate concentration.
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Claims 9
Claim · model-written summary
Sorghum dry matter yield had a quadratic relationship with N rate across site-years.
SorghumNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A quadratic model described the relationship between sorghum DM and N rate across the combined site-years”
Claim · model-written summary
Maximum dry matter yield was 6530 kg ha−1 at 100 kg N ha−1.
- Treatment
- N application rate of 100 kg N ha−1e0
- Outcome
- DM yielde0
- Direction
- Maximume0
- Value
- 6530 kg ha−1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maximum DM yield of 6530 kg ha−1 was produced with N application rate of 100 kg N ha−1”
t0“sorghum”
Claim · model-written summary
The economic optimum N rate ranged from 55 to 70 kg N ha−1 depending on costs and hay price.
- Outcome
- economic optimum N ratee0
- Value
- 55 to 70 kg N ha−1e0
- Qualifier
- sorghum hay price and N fertilizer costse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The economic optimum N rate ranged from 55 to 70 kg N ha−1 depending on sorghum hay price and N fertilizer costs”
Claim · model-written summary
Crude protein concentration increased with N fertilizer application.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crude protein concentration increased with N fertilizer application”
t0“sorghum”
Claim · model-written summary
N rates above 70 kg N ha−1 led to forage nitrate concentration above 3000 mg kg−1.
- Treatment
- N rates beyond 70 kg N ha−1e0
- Outcome
- forage nitrate concentrationse0
- Direction
- greater thane0
- Value
- 3000 mg kg−1e0
- Comparator
- safe limite0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N rates beyond 70 kg N ha−1 resulted in forage nitrate concentrations greater than safe limit of 3000 mg kg−1”
t0“sorghum”
Claim · model-written summary
Nitrogen uptake increased with N fertilizer application.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen uptake increased with N fertilizer application”
t0“sorghum”
Claim · model-written summary
Nitrogen use efficiency decreased with increasing N fertilizer rates.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrogen use efficiency and N recovery decreased with increasing N fertilizer rates”
t0“sorghum”
Claim · model-written summary
N recovery decreased with increasing N fertilizer rates.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrogen use efficiency and N recovery decreased with increasing N fertilizer rates”
t0“sorghum”
Claim · model-written summary
The authors recommend 55–70 kg N ha−1 for economic dry matter yield with safe nitrate concentration.
Verbatim
e0“forage sorghum required 55–70 kg N ha−1 to produce an economic optimum DM yields with safe nitrate concentration”
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See all 118 papers →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.