Abstract
Use of conservation tillage methods, including ridge‐tillage, increases crop residue cover which can increase loss of urea‐based fertilizers. Objectives of this study were to evaluate N sources, rates, methods, and times of application for ridge‐tilled, furrow‐irrigated corn ( Zea mays L.) on a Crete silt loam soil (fine, montmorillionitic, mesic Pachic, Argiustoll) near Scandia, KS. When averaged over 5‐yr, grain yields were less with urea‐ammonium nitrate (UAN) broadcast and dribbled treatments than with anhydrous ammonia (AA) preplant knifed, 28% UAN solution preplant knifed, and split applications of UAN knifed or dribbled. Surface dribbled UAN proved to be no more effective than surface broadcasting. Split applications of dribbled UAN gave greater yields than a single preplant dribble application. Grain yields were unaffected by splitting knife applications of UAN. No differences occurred in grain yield, grain N concentration, or amount of N removed in the grain between the AA and the UAN knife‐injected treatments. Yield was unaffected by application method x N rate interactions. Higher N rates did not compensate for more inefficient application systems. Corn grain N concentration and grain N removed followed the same trends as grain yields. Maximal grain yield, regardless of application treatment, was achieved with 158 lb N/acre. In April of 1990 and 1991, total amount of residual soil nitrate N was greater in plots receiving annual applications of 200 lb N/acre than in plots receiving 50 or 100 lb N/acre. In 1991, plots that received knife‐injected N at the 200 lb/acre rate contained much more nitrate‐N than plots in which N was surface applied, indicating that immobilization of N within the crop residue or some volatilization losses could have occurred. Research Question The use of conservation tillage practices, including ridge‐tillage, have increased greatly in the past 10 yr because of their effectiveness in conserving soil and water. In the ridge system, tillage at planting time is confined to a narrow strip on top of the ridge. The large amount of residue left on the soil surface can affect loss of urea‐based fertilizers through volatilization and immobilization. The objective of this study was to evaluate the effects of application method and N‐rate on furrow irrigated ridge‐tilled corn. Literature Summary Large amounts of surface crop residue can affect loss of N fertilizers through immobilization and volatilization, and often are associated with greater denitrification rates. Many methods have been evaluated for applying N fertilizers to no‐tillage corn, but little information is available on N application methods and timing in ridge‐till systems. Study Description A furrow‐irrigated experiment was conducted at the Irrigation Experiment Field, located near Scandia, KS, on a Crete silt loam soil. Treatments included four preplant N application methods (knife‐injected anhydrous ammonia, knife‐injected urea‐ammonium nitrate (UAN), surface broadcast UAN, surface‐dribbled UAN, and two split application systems (dribbled and knife‐injected UAN). All application methods were evaluated at N rates of 50, 100, and 200 lb/acre. A no N check treatment was also included. Applied Questions How did application method and N rate affect corn grain yield? When averaged over 5 yr, grain yields were significantly less in the UAN broadcast and dribble treatments than in the four other application systems (Table ). Surface applying UAN in a band failed to improve yields over broadcasting. Split applications of dribbled UAN gave greater yields than a single preplant application. Grain yields were unaffected by splitting knife‐injected applications of UAN. No differences occurred in grain yield between the anhydrous ammonia and UAN knife‐injected treatments. No interaction was detected between application method and N rate in any year of the experiment. Higher N rates did not compensate for inefficient application systems. Maximal grain yield, regardless of application treatment, was achieved with 158 lb N/acre. What effect did application method and N rate have on the amount of inorganic N (nitrate‐N + ammonium‐N) in the soil profile? In April 1991, total amounts of both ammonium‐N and nitrate‐N (0–24 in.) showed interactions between application method and N rate. Inorganic N at the 200 lb/acre rate was much greater in all three knife systems than in the surface applied systems, whereas little difference occurred among application systems at the 50 and 100 lb N/acre rates. The lesser amounts of inorganic N in the surface applied systems may indicate that volatilization did occur. There were no differences between nitrate‐N amount in the preplant knife and split knife UAN treatments. Applying part of the N closer to the time of use by the corn plant did not reduce nitrate‐N carryover when N was applied at the 200 lb/acre rate. When N is applied at rates greater than need for maximal yield, nitrate‐N can accumulate in the soil profile and be subject to leaching. Recommendations For ridge‐tilled corn, knifing N below the residue (either anhydrous ammonia or UAN) produces greater yields than surface broadcasting or dribbling. Applying additional N will not compensate for inefficient application methods. When N fertilizer is applied in excess of crop needs, large amounts of nitrates will accumulate in the soil profile. Effect of application method on corn grain yield (average 1987–1991). Application method bu/acre 0 N check 94 Anhydrous ammonia; preplant, knife 157 UAN; preplant, knife 156 UAN; preplant, broadcast 143 UAN; preplant, dribble 145 UAN; split, knife 155 UAN; split, dribble 150 Inorganic N (ammonium‐N + nitrate‐N) amounts in a 24‐in. soil profile. image
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Claims 13
Claim · model-written summary
Broadcast and dribbled UAN yielded less grain than knife applied or split systems.
- Taxon
- corn
Zea mays subsp. mayst0 - Treatment
- broadcast and dribbled treatmentse0
- Outcome
- grain yieldse0
- Direction
- lesse0
- Comparator
- anhydrous ammonia (AA) preplant knifede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“grain yields were less with urea‐ammonium nitrate (UAN) broadcast and dribbled treatments than with anhydrous ammonia (AA) preplant knifed, 28% UAN solution preplant knifed, and split applications of UAN knifed or dribbled”
t0“Corn”
Claim · model-written summary
Surface dribbled UAN was no better than broadcasting.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- Surface dribbled UANe0
- Outcome
- no more effectivee0
- Direction
- no more effectivee0
- Comparator
- surface broadcastinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Surface dribbled UAN proved to be no more effective than surface broadcasting”
t0“Corn”
Claim · model-written summary
Split dribbled UAN yielded more than a single preplant dribble.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- Split applications of dribbled UANe0
- Outcome
- yieldse0
- Direction
- greatere0
- Comparator
- single preplant dribble applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Split applications of dribbled UAN gave greater yields than a single preplant dribble application”
t0“Corn”
Claim · model-written summary
Splitting knife UAN application did not alter grain yield.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- splitting knife applications of UANe0
- Outcome
- Grain yieldse0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grain yields were unaffected by splitting knife applications of UAN”
t0“Corn”
Claim · model-written summary
AA and UAN knife treatments had similar grain yield, grain N concentration and N removal.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- AAe0
- Outcome
- grain yield, grain N concentration, or amount of N removed in the graine0
- Direction
- No differencese0
- Comparator
- UAN knife‐injected treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No differences occurred in grain yield, grain N concentration, or amount of N removed in the grain between the AA and the UAN knife‐injected treatments”
t0“Corn”
Claim · model-written summary
Application method by N rate interaction did not affect yield.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- application method x N rate interactionse0
- Outcome
- Yielde0
- Direction
- unaffectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield was unaffected by application method x N rate interactions”
t0“Corn”
Claim · model-written summary
Higher N rates did not compensate for inefficient application.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- Higher N ratese0
- Outcome
- did not compensatee0
- Direction
- did not compensatee0
- Comparator
- more inefficient application systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher N rates did not compensate for more inefficient application systems”
t0“Corn”
Claim · model-written summary
Maximum grain yield occurred at 158 lb N/acre.
- Taxon
- cornZea mays subsp. mayst0
- Outcome
- Maximal grain yielde0
- Direction
- Maximale0
- Value
- 158 lb N/acree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn grain N concentration and grain N removed followed the same trends as grain yields. Maximal grain yield, regardless of application treatment, was achieved with 158 lb N/acre”
t0“Corn”
Claim · model-written summary
Residual soil nitrate was higher after 200 lb N/acre than 50 or 100 lb N/acre.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- 200 lb N/acree0
- Outcome
- residual soil nitrate Ne0
- Direction
- greatere0
- Comparator
- 50 or 100 lb N/acree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total amount of residual soil nitrate N was greater in plots receiving annual applications of 200 lb N/acre than in plots receiving 50 or 100 lb N/acre”
t0“Corn”
Claim · model-written summary
At 200 lb N/acre, knife injection left more soil nitrate than surface application.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- knife‐injected N at the 200 lb/acre ratee0
- Outcome
- nitrate‐Ne0
- Direction
- much moree0
- Comparator
- surface appliede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plots that received knife‐injected N at the 200 lb/acre rate contained much more nitrate‐N than plots in which N was surface applied”
t0“Corn”
Claim · model-written summary
At 200 lb N/acre, knife systems left more inorganic N than surface systems.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- 200 lb/acre ratee0
- Outcome
- Inorganic Ne0
- Direction
- much greatere0
- Comparator
- surface applied systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Inorganic N at the 200 lb/acre rate was much greater in all three knife systems than in the surface applied systems”
t0“Corn”
Claim · model-written summary
Nitrate amounts did not differ between preplant and split knife UAN.
- Taxon
- cornZea mays subsp. mayst0
- Treatment
- preplant knifee0
- Outcome
- nitrate‐N amounte0
- Direction
- no differencese0
- Comparator
- split knife UAN treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no differences between nitrate‐N amount in the preplant knife and split knife UAN treatments”
t0“Corn”
Claim · model-written summary
The authors recommend knife placement of N below residue for ridge tilled corn.
- Taxon
- cornZea mays subsp. mayse0
- Outcome
- knifing N below the residuee0
- Direction
- greater yieldse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For ridge‐tilled corn, knifing N below the residue (either anhydrous ammonia or UAN) produces greater yields than surface broadcasting or dribbling”
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