Abstract
Current economic conditions in agriculture and environmental concerns over ground water pollution have producers seeking more efficient methods of crop production. Agriculture has also become very dependent upon fossil fuels for inputs such as nitrogen fertilizer and irrigation water application. A field experiment was initiated in 1982, at Mead, NE, to examine the effects of manure and increasing levels of N, P, K, and micronutrients on grain yield, return over variable costs (ROVC), and energy input of a corn(Zea mays L.)-soybean(Glycine max L.)-wheat(Triticum aestivum L.) rotation (CSW) versus continuous corn (CC). Rotation corn (RC) grain yields were 20 percent higher than CC at optimum N-rate. Fertilizer N and P increased corn and wheat yields, respectively, but soybean yields were unaffected by fertilizer nutrients. Corn and wheat grain protein content were related to the rate of N applied. Residual NO$\sb3$-N levels were low regardless of previous crop where no N was applied, when 320 lb N a$\sp{-1}$ was applied to corn, residual levels ranged from 91 to 491 lb a$\sp{-1}$. Continuous corn ROVC was slightly lower than ROVC for CSW, however, the variability of ROVC was less for CSW than CC indicating that a measure of risk avoidance could be attained by growing a rotation of crops. Energy input requirements for CC, RC, soybean, and wheat were 3183, 3271, 1123, and 763 Mcal a$\sp{-1}$ respectively. Nitrogen fertilizer (33%) and irrigation (28%) accounted for the greatest use of energy for corn production. Analysis of costs of production showed that CC was more affected by energy price increases than CSW. Growing corn in a rotation provides yield advantages and also reduces the variability of income from year to year. Soil test levels of nutrients were increased by seven years of manure or fertilizer addition, but crop yields were not influenced by the increase. The sufficiency concept for fertilizer recommendations represents the best management approach to account for changes in soil nutrient levels.
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Claims 18
Claim · model-written summary
Rotation corn yield was 20 percent higher than continuous corn at optimum nitrogen rate.
- Taxon
- corn
Zea mays subsp. mayse0 - Treatment
- Rotation corn (RC)e0
- Outcome
- grain yieldse0
- Direction
- highere0
- Value
- 20 percente0
- Qualifier
- optimum N-ratee0
- Comparator
- CCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rotation corn (RC) grain yields were 20 percent higher than CC at optimum N-rate”
Claim · model-written summary
Fertilizer nitrogen increased corn yield.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- Fertilizer Ne0
- Outcome
- corne0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer N and P increased corn and wheat yields, respectively”
Claim · model-written summary
Fertilizer phosphorus increased wheat yield.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- Pe0
- Outcome
- wheat yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer N and P increased corn and wheat yields, respectively”
Claim · model-written summary
Fertilizer nutrients did not affect soybean yield.
- Taxon
- soybean
Glycine maxe0 - Treatment
- fertilizer nutrientse0
- Outcome
- soybean yieldse0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“soybean yields were unaffected by fertilizer nutrients”
Claim · model-written summary
Corn grain protein content was related to applied nitrogen rate.
- Taxon
- CornZea mays subsp. mayse0
- Treatment
- rate of N appliede0
- Outcome
- grain protein contente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn and wheat grain protein content were related to the rate of N applied”
Claim · model-written summary
Wheat grain protein content was related to applied nitrogen rate.
- Taxon
- wheatTriticum aestivume0
- Treatment
- rate of N appliede0
- Outcome
- grain protein contente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn and wheat grain protein content were related to the rate of N applied”
Claim · model-written summary
Continuous corn return over variable costs was slightly lower than crop rotation.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- ROVCe0
- Direction
- lowere0
- Comparator
- CSWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Continuous corn ROVC was slightly lower than ROVC for CSW”
Claim · model-written summary
Return variability was lower for crop rotation than continuous corn.
- Taxon
- cornZea mays subsp. mayse1
- Outcome
- variability of ROVCe0
- Direction
- lesse0
- Comparator
- CCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the variability of ROVC was less for CSW than CC”
e1“corn(Zea mays L.)-soybean(Glycine max L.)-wheat(Triticum aestivum L.) rotation (CSW) versus continuous corn (CC)”
Claim · model-written summary
Continuous corn required 3183 Mcal per acre of energy input.
- Taxon
- cornZea mays subsp. mayse1
- Material
- CCe0
- Outcome
- Energy input requirementse0
- Value
- 3183e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy input requirements for CC, RC, soybean, and wheat were 3183, 3271, 1123, and 763 Mcal a$\sp{-1}$ respectively”
e1“continuous corn (CC)”
Claim · model-written summary
Rotation corn required 3271 Mcal per acre of energy input.
- Taxon
- cornZea mays subsp. mayse1
- Material
- RCe0
- Outcome
- Energy input requirementse0
- Value
- 3271e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy input requirements for CC, RC, soybean, and wheat were 3183, 3271, 1123, and 763 Mcal a$\sp{-1}$ respectively”
e1“Rotation corn (RC)”
Claim · model-written summary
Soybean required 1123 Mcal per acre of energy input.
- Taxon
- soybeanGlycine maxe0
- Outcome
- Energy input requirementse0
- Value
- 1123e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy input requirements for CC, RC, soybean, and wheat were 3183, 3271, 1123, and 763 Mcal a$\sp{-1}$ respectively”
Claim · model-written summary
Wheat required 763 Mcal per acre of energy input.
- Taxon
- wheatTriticum aestivume0
- Outcome
- Energy input requirementse0
- Value
- 763e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Energy input requirements for CC, RC, soybean, and wheat were 3183, 3271, 1123, and 763 Mcal a$\sp{-1}$ respectively”
Claim · model-written summary
Nitrogen fertilizer accounted for 33% of corn production energy use.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- Nitrogen fertilizere0
- Outcome
- use of energy for corn productione0
- Value
- 33%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilizer (33%) and irrigation (28%) accounted for the greatest use of energy for corn production”
Claim · model-written summary
Irrigation accounted for 28% of corn production energy use.
- Taxon
- cornZea mays subsp. mayse0
- Treatment
- irrigatione0
- Outcome
- use of energy for corn productione0
- Value
- 28%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilizer (33%) and irrigation (28%) accounted for the greatest use of energy for corn production”
Claim · model-written summary
Continuous corn was more affected by energy price increases than rotation.
- Taxon
- cornZea mays subsp. mayse1
- Outcome
- affected by energy price increasese0
- Direction
- moree0
- Comparator
- CSWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CC was more affected by energy price increases than CSW”
e1“continuous corn (CC)”
Claim · model-written summary
Manure or fertilizer increased soil nutrient test levels over seven years.
- Treatment
- manure or fertilizer additione0
- Outcome
- Soil test levels of nutrientse0
- Direction
- increasede0
- Qualifier
- seven yearse0
Not reportedTaxonComparator
Verbatim
e0“Soil test levels of nutrients were increased by seven years of manure or fertilizer addition”
e1“corn(Zea mays L.)-soybean(Glycine max L.)-wheat(Triticum aestivum L.) rotation”
Claim · model-written summary
Crop yields did not respond to increased soil nutrient test levels.
- Taxon
- cornZea mays subsp. mayse2
- Treatment
- manure or fertilizer additione1
- Outcome
- crop yieldse0
- Direction
- not influencede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“crop yields were not influenced by the increase”
e1“Soil test levels of nutrients were increased by seven years of manure or fertilizer addition”
e2“corn(Zea mays L.)-soybean(Glycine max L.)-wheat(Triticum aestivum L.) rotation”
Claim · model-written summary
The authors recommend the sufficiency concept for fertilizer decisions based on soil nutrient levels.
- Taxon
- cornZea mays subsp. mayse1
- Outcome
- sufficiency concept for fertilizer recommendationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The sufficiency concept for fertilizer recommendations represents the best management approach to account for changes in soil nutrient levels”
e1“corn(Zea mays L.)-soybean(Glycine max L.)-wheat(Triticum aestivum L.) rotation”
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