Abstract
Abstract This study comparing corn yields from different rates of applied N under no‐tillage and conventional culture was prompted by numerous field observations in Maryland that no‐till corn, with low to moderate rates of N, often showed more pronounced N deficiency symptoms than did conventionally tilled corn. Little is known regarding the relative N requirements of untilled corn grown in cover‐crop residues as compared to conventional tillage. The purpose of this study was therefore, to determine whether tillage method affected optimal crop requirements for fertilizer N. First‐year effects of tillage method and fertilizer N applications (0, 45, 90, 135, and 180 kg/ha) on corn ( Zea mays L.) yields, N uptake by the crop, mineral N accumulation in the soil, and total and potentially mineralizable soil N are reported. With suboptimal N rates, N deficiency symptoms were more severe throughout the season on untilled than on cultivated plots. However, the optimal level of applied N for grain and dry matter yields did not differ with tillage method. After grain harvest, the amount and distribution of residual mineral N in the root zone for a given rate of applied N were similar in tilled and untilled plots at two locations (Poplar Hill and Plant Research Farm). At the third site (Wye Institute), however, residual mineral soil N was higher with conventional than with no tillage. These differences were attributed to variation among sites in amounts of precipitation between planting and harvest, as it affected relative water infiltration in tilled and untilled plots. Total residual mineral N in the root zone tended to increase with N application rate. Between harvest (1973) and planting (1974), however, most of the residual mineral fertilizer N was removed by the cover crop or lost. Total soil organic N to a depth of 30 cm was unaffected by N rate or tillage method during one cropping season. At one rate, however, potentially mineralizable N was higher in untilled than in tilled plots. Studies are continuing on two of the sites, with l5 N‐lepleted fertilizer, to determine relative changes with time in soil N status as influenced by tillage method.
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Claims 8
Claim · model-written summary
At suboptimal nitrogen rates, untilled corn showed more severe nitrogen deficiency symptoms than cultivated corn.
- Taxon
- corn
Zea mays subsp. mayse1 - Treatment
- untillede0
- Outcome
- N deficiency symptomse0
- Direction
- more severee0
- Qualifier
- suboptimal N ratese0
- Comparator
- cultivated plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With suboptimal N rates, N deficiency symptoms were more severe throughout the season on untilled than on cultivated plots”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
The optimal applied nitrogen level for corn grain and dry matter yields did not differ by tillage method.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- tillage methode0
- Outcome
- grain and dry matter yieldse0
- Direction
- did not differe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the optimal level of applied N for grain and dry matter yields did not differ with tillage method”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
Residual mineral nitrogen amount and distribution were similar in tilled and untilled root zones at Poplar Hill and Plant Research Farm.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- tillede0
- Outcome
- amount and distribution of residual mineral N in the root zonee0
- Direction
- similare0
- Comparator
- untilled plotse0
- Setting
- Poplar Hill and Plant Research Farme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the amount and distribution of residual mineral N in the root zone for a given rate of applied N were similar in tilled and untilled plots at two locations (Poplar Hill and Plant Research Farm)”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
Residual mineral soil nitrogen was higher with conventional than no tillage at Wye Institute.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- conventionale0
- Outcome
- residual mineral soil Ne0
- Direction
- highere0
- Comparator
- no tillagee0
- Setting
- Wye Institutee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the third site (Wye Institute), however, residual mineral soil N was higher with conventional than with no tillage”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
Total residual mineral nitrogen in the root zone tended to increase with nitrogen application rate.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- N application ratee0
- Outcome
- Total residual mineral N in the root zonee0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total residual mineral N in the root zone tended to increase with N application rate”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
Most residual mineral fertilizer nitrogen was removed by the cover crop or lost between harvest and planting.
- Taxon
- cornZea mays subsp. mayse1
- Outcome
- residual mineral fertilizer N was removed by the cover crop or loste0
- Qualifier
- Between harvest (1973) and planting (1974)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Between harvest (1973) and planting (1974), however, most of the residual mineral fertilizer N was removed by the cover crop or lost”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
Total soil organic nitrogen to 30 cm was unaffected by nitrogen rate or tillage method over one crop season.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- N rate or tillage methode0
- Outcome
- Total soil organic N to a depth of 30 cme0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total soil organic N to a depth of 30 cm was unaffected by N rate or tillage method during one cropping season”
e1“corn ( Zea mays L.) yields”
Claim · model-written summary
At one nitrogen rate, potentially mineralizable nitrogen was higher in untilled plots.
- Taxon
- cornZea mays subsp. mayse1
- Treatment
- untillede0
- Outcome
- potentially mineralizable Ne0
- Direction
- highere0
- Comparator
- tilled plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At one rate, however, potentially mineralizable N was higher in untilled than in tilled plots”
e1“corn ( Zea mays L.) yields”
The same questions in other papers
tillage · yield · Zea mays (maize)Positive and negative results
286 papers in the same direction as this paper · 812 in the opposite direction
- no effect
- no effect
- positive
1,095 papers more in this group
See all 1,099 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.