Abstract
The status of soil nutrients, their depletion or build-up and crop productivity after a twenty-three years of intensive rice-wheat cropping under various fertilizer treatments was studied. In general, yields of both rice and wheat started declining after ten years of cropping. Omission of P fertilizer accelerated the decline in yields. Continuous application of N and K fertilizers revealed a marginal change in soil available N and K over time, but about 3- and 2- fold increase in available P and S, respectively, were observed by regular application of P fertilizer (SSP: 7% P, 12% S) over 23 years. The status of organic carbon increased in all the treatments except control plots. There was a general reduction in the contents of DTPA extractable Zn, Cu and Mn. However, there was overall increase in the DTPA-Fe over the years where the plots received single superphosphate. The combined effect of deficiency of P, K, S and Zn, toxicity of Fe and imbalances due to antagonisms between P-Zn, Fe-Zn and S-Zn seemed to be responsible for the decline in the productivity of rice and wheat. Balanced and high doses of NPK fertilizers and inclusion of S and Zn in fertilizer schedule are required to maintain soil fertility and sustain grain yields in the long run.
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Claims 9
Claim · model-written summary
Yields of rice and wheat started declining after ten years of continuous cropping.
- Taxon
- rice and wheat
Oryza sativa
Triticum aestivume1 - Outcome
- yieldse1
- Direction
- declininge1
- Qualifier
- after ten years of croppinge1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
Claim · model-written summary
Omitting P fertilizer accelerated the decline in rice and wheat yields.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- Omission of P fertilizere2
- Outcome
- decline in yieldse2
- Direction
- acceleratede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e2“Omission of P fertilizer accelerated the decline in yields”
Claim · model-written summary
Continuous N and K fertilizer application gave a marginal change in soil available N and K over time.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- Continuous application of N and K fertilizerse3
- Outcome
- soil available N and Ke3
- Direction
- marginal changee3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e3“Continuous application of N and K fertilizers revealed a marginal change in soil available N and K over time”
Claim · model-written summary
Regular P fertilizer application raised available P and S about 3- and 2-fold respectively over 23 years.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- regular application of P fertilizer (SSP: 7% P, 12% S)e4
- Outcome
- available P and Se4
- Direction
- increasee4
- Value
- 3- and 2- folde4
- Qualifier
- over 23 yearse4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e4“about 3- and 2- fold increase in available P and S, respectively, were observed by regular application of P fertilizer (SSP: 7% P, 12% S) over 23 years”
Claim · model-written summary
Soil organic carbon increased in all fertilizer treatments except the control plots.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- all the treatmentse5
- Outcome
- status of organic carbone5
- Direction
- increasede5
- Comparator
- control plotse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e5“The status of organic carbon increased in all the treatments except control plots”
Claim · model-written summary
DTPA-extractable Zn, Cu and Mn generally decreased in soil under the long-term cropping.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Outcome
- contents of DTPA extractable Zn, Cu and Mne6
- Direction
- reductione6
- Qualifier
- generale6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e6“There was a general reduction in the contents of DTPA extractable Zn, Cu and Mn”
Claim · model-written summary
DTPA-Fe increased over the years in plots that received single superphosphate.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- single superphosphatee7
- Outcome
- DTPA-Fee7
- Direction
- increasee7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e7“there was overall increase in the DTPA-Fe over the years where the plots received single superphosphate”
Claim · model-written summary
Combined nutrient deficiencies and Fe toxicity with nutrient antagonisms are thought to explain the decline in rice and wheat productivity.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Outcome
- decline in the productivity of rice and wheate7
- Qualifier
- combined effect of deficiency of P, K, S and Zn, toxicity of Fe and imbalances due to antagonisms between P-Zn, Fe-Zn and S-Zne7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e7“The combined effect of deficiency of P, K, S and Zn, toxicity of Fe and imbalances due to antagonisms between P-Zn, Fe-Zn and S-Zn seemed to be responsible for the decline in the productivity of rice and wheat”
Claim · model-written summary
Balanced and high NPK doses with S and Zn are recommended to maintain soil fertility and sustain grain yields in the long run.
- Taxon
- rice and wheatOryza sativaTriticum aestivume1
- Treatment
- Balanced and high doses of NPK fertilizers and inclusion of S and Zn in fertilizer schedulee6
- Outcome
- soil fertility and sustain grain yieldse6
- Qualifier
- in the long rune6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“In general, yields of both rice and wheat started declining after ten years of cropping”
e6“Balanced and high doses of NPK fertilizers and inclusion of S and Zn in fertilizer schedule are required to maintain soil fertility and sustain grain yields in the long run”
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See all 305 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.