Abstract
In a field experiment initiated in the 1972/73 rabi season (November–March) on an acidic soil in the western Himalayas of India, continuous cropping for 25 years with nitrogen fertilizer alone reduced the grain yields of maize ( Zea mays ) and wheat ( Triticum aestivum ) to almost zero. Based on five-year moving average values, the application of 100% NP resulted in a reduction of grain yields of maize and wheat crops by 67 and 19% respectively during 1994 to1998 compared with 1973 to 1977. The crops did not respond to K application during the initial years of cropping, but a significant reduction in crop yields was observed in the absence of K after five years of continuous cropping. With the integrated use of chemical fertilizers (100% NPK) and farmyard manure, the pooled grain yields of 25 years were about 4600 and 3300 kg ha −1 for maize and wheat respectively. Corresponding yields with the use of chemical fertilizers and lime (100% NPK + lime) were 4000 and 3100 kg ha −1 respectively. The use of nitrogenous fertilizer alone aggravated the problem of soil acidity by lowering the pH from 5.8 to 4.7 after 25 years. In almost all the treatments, the organic carbon content increased: a marginal decrease occurred in the 100% N and control plots. Even under optimum application rates, the available N and K status decreased with time. Again with the exception of the control plots, the contents of the Diphenyl Triamine Penta Acetic Acid-extractable micronutrients were sufficiently high for the crops in all the treatments. The available sulphur decreased with the use of di-ammonium phosphate as the P source, which drastically reduced the yields of both crops. In the N-alone treatment the weed flora also changed with the change in soil environment. There is a need to review fertilizer recommendations in this region of India.
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Claims 19
Claim · model-written summary
Nitrogen alone reduced maize grain yield to almost zero after 25 years.
- Treatment
- nitrogen fertilizer alonee0
- Outcome
- grain yields of maizee0
- Direction
- reducede0
- Value
- almost zeroe0
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“continuous cropping for 25 years with nitrogen fertilizer alone reduced the grain yields of maize ( Zea mays ) and wheat ( Triticum aestivum ) to almost zero”
Claim · model-written summary
Nitrogen alone reduced wheat grain yield to almost zero after 25 years.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- nitrogen fertilizer alonee0
- Outcome
- grain yields of maize ( Zea mays ) and wheate0
- Direction
- reducede0
- Value
- almost zeroe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“continuous cropping for 25 years with nitrogen fertilizer alone reduced the grain yields of maize ( Zea mays ) and wheat ( Triticum aestivum ) to almost zero”
Claim · model-written summary
Under 100% NP, maize grain yield fell 67% in 1994 to 1998 relative to 1973 to 1977.
- Treatment
- 100% NPe0
- Outcome
- grain yields of maizee0
- Direction
- reductione0
- Value
- 67e0
- Comparator
- 1973 to 1977e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the application of 100% NP resulted in a reduction of grain yields of maize and wheat crops by 67 and 19% respectively during 1994 to1998 compared with 1973 to 1977”
Claim · model-written summary
Under 100% NP, wheat grain yield fell 19% in 1994 to 1998 relative to 1973 to 1977.
- Taxon
- wheatTriticum aestivume0
- Treatment
- 100% NPe0
- Outcome
- grain yields of maize and wheat cropse0
- Direction
- reductione0
- Value
- 19%e0
- Comparator
- 1973 to 1977e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the application of 100% NP resulted in a reduction of grain yields of maize and wheat crops by 67 and 19% respectively during 1994 to1998 compared with 1973 to 1977”
Claim · model-written summary
Crops initially did not respond to K application.
Not reportedComparator
Verbatim
e0“The crops did not respond to K application during the initial years of cropping”
t0“MAIZE AND WHEAT”
Claim · model-written summary
After five years, crop yields were significantly lower without K.
Not reportedComparator
Verbatim
e0“a significant reduction in crop yields was observed in the absence of K after five years of continuous cropping”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Integrated 100% NPK and farmyard manure produced pooled maize grain yield of about 4600 kg ha −1.
- Treatment
- chemical fertilizers (100% NPK) and farmyard manuree0
- Outcome
- pooled grain yieldse0
- Value
- 4600e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With the integrated use of chemical fertilizers (100% NPK) and farmyard manure, the pooled grain yields of 25 years were about 4600 and 3300 kg ha −1 for maize and wheat respectively”
Claim · model-written summary
Integrated 100% NPK and farmyard manure produced pooled wheat grain yield of about 3300 kg ha −1.
- Taxon
- wheatTriticum aestivume0
- Treatment
- chemical fertilizers (100% NPK) and farmyard manuree0
- Outcome
- pooled grain yieldse0
- Value
- 3300 kg ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With the integrated use of chemical fertilizers (100% NPK) and farmyard manure, the pooled grain yields of 25 years were about 4600 and 3300 kg ha −1 for maize and wheat respectively”
Claim · model-written summary
With 100% NPK and lime, maize grain yield was 4000 kg ha −1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corresponding yields with the use of chemical fertilizers and lime (100% NPK + lime) were 4000 and 3100 kg ha −1 respectively”
t0“MAIZE AND WHEAT”
Claim · model-written summary
With 100% NPK and lime, wheat grain yield was 3100 kg ha −1.
- Taxon
- WHEATTriticum aestivumt0
- Treatment
- 100% NPK + limee0
- Outcome
- yieldse0
- Value
- 3100 kg ha −1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corresponding yields with the use of chemical fertilizers and lime (100% NPK + lime) were 4000 and 3100 kg ha −1 respectively”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Nitrogen alone lowered soil pH from 5.8 to 4.7 over 25 years.
- Taxon
- MAIZE AND WHEATt0
- Treatment
- nitrogenous fertilizer alonee0
- Outcome
- soil aciditye0
- Direction
- loweringe0
- Value
- 5.8 to 4.7e0
Not reportedComparator
Verbatim
e0“The use of nitrogenous fertilizer alone aggravated the problem of soil acidity by lowering the pH from 5.8 to 4.7 after 25 years”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Soil organic carbon increased in almost all treatments.
Verbatim
e0“In almost all the treatments, the organic carbon content increased”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Soil organic carbon marginally decreased in 100% N and control plots.
Verbatim
e0“a marginal decrease occurred in the 100% N and control plots”
e1“the organic carbon content increased”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Available soil N and K decreased over time even at optimum application rates.
Verbatim
e0“Even under optimum application rates, the available N and K status decreased with time”
t0“MAIZE AND WHEAT”
Claim · model-written summary
DTPA-extractable micronutrients were sufficiently high for crops in all treatments except control.
Verbatim
e0“with the exception of the control plots, the contents of the Diphenyl Triamine Penta Acetic Acid-extractable micronutrients were sufficiently high for the crops in all the treatments”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Di-ammonium phosphate as P source decreased available sulphur.
- Taxon
- MAIZE AND WHEATt0
- Treatment
- di-ammonium phosphatee0
- Outcome
- available sulphure0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“The available sulphur decreased with the use of di-ammonium phosphate as the P source”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Use of di-ammonium phosphate as P source drastically reduced yields of both crops.
- Taxon
- MAIZE AND WHEATt0
- Treatment
- di-ammonium phosphatee0
- Outcome
- yields of both cropse0
- Direction
- reducede0
Not reportedComparator
Verbatim
e0“The available sulphur decreased with the use of di-ammonium phosphate as the P source, which drastically reduced the yields of both crops”
t0“MAIZE AND WHEAT”
Claim · model-written summary
Weed flora changed in the N-alone treatment as soil environment changed.
Verbatim
e0“In the N-alone treatment the weed flora also changed with the change in soil environment”
t0“MAIZE AND WHEAT”
Claim · model-written summary
The authors recommend reviewing fertilizer recommendations in the region.
Verbatim
e0“There is a need to review fertilizer recommendations in this region of India”
t0“MAIZE AND WHEAT”
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See all 260 papers →8 of 10 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.