Abstract
There is a diversity of locally available nitrogen (N)-rich organic materials in Samoa. However, none of them was evaluated for their N supplying capacity after composting in Samoan Inceptisols for vegetable cultivation. Thus, N-releasing capacity of five composted organic amendments (OAs) namely macuna, gliricidia, erythrina, lawn grass and giant taro, and their two application rates (10 and 20 t ha−1) were assessed through a laboratory incubation and a crop response study using Chinese cabbage as a test crop. Among the OAs, composted mucuna was characterized by a higher total N (2.91%), organic C (63.6%) and NO3−N content (341 mg N kg−1). A significant difference in N mineralization was observed among the OAs as well as application rates. The highest N mineralization was recorded in composted mucuna followed by gliricidia, erythrina, lawn grass, and giant taro. A crop response study also showed a similar trend. Mucuna treatment had the highest biomass yield and N uptake followed by gliricidia, erythrina, lawn grass, and giant taro. Leguminous composted OAs @ 20 t ha−1 performed substantially better in all the plant growth and yield parameters, and N uptake compared to 10 t ha−1 that was not the case for non-leguminous OAs. Thus, non-leguminous OAs should be applied at 10 t ha−1. All the composted leguminous OAs showed promising results while mucuna was the best in both the application rates. Therefore, mucuna can be promoted to supply N for crop cultivation in Samoa, other Pacific Islands and tropical countries where N fertilizer is costly and not easily available.
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Claims 6
Claim · model-written summary
Mucuna compost had the highest nitrogen, carbon, and nitrate content among amendments.
- Taxon
- Chinese Cabbage
Brassica rapa subsp. pekinensist0 - Treatment
- composted mucunae0
- Outcome
- total N (2.91%), organic C (63.6%) and NO3−N content (341 mg N kg−1)e0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among the OAs, composted mucuna was characterized by a higher total N (2.91%), organic C (63.6%) and NO3−N content (341 mg N kg−1).”
t0“Chinese Cabbage”
Claim · model-written summary
Nitrogen mineralization differed among composted amendments and rates.
- Taxon
- Chinese CabbageBrassica rapa subsp. pekinensist0
- Treatment
- OAse0
- Outcome
- N mineralizatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A significant difference in N mineralization was observed among the OAs as well as application rates.”
t0“Chinese Cabbage”
Claim · model-written summary
Mucuna compost gave the greatest cabbage biomass yield and nitrogen uptake, followed by gliricidia, erythrina, lawn grass and giant taro.
- Taxon
- Chinese CabbageBrassica rapa subsp. pekinensist0
- Treatment
- Mucuna treatmente0
- Outcome
- biomass yield and N uptakee0
- Direction
- higheste0
- Comparator
- gliricidia, erythrina, lawn grass, and giant taroe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mucuna treatment had the highest biomass yield and N uptake followed by gliricidia, erythrina, lawn grass, and giant taro.”
t0“Chinese Cabbage”
Claim · model-written summary
Leguminous compost at 20 t ha−1 improved cabbage growth, yield and nitrogen uptake over 10 t ha−1.
- Taxon
- Chinese CabbageBrassica rapa subsp. pekinensist0
- Treatment
- Leguminous composted OAs @ 20 t ha−1e0
- Outcome
- plant growth and yield parameters, and N uptakee0
- Direction
- substantially bettere0
- Comparator
- 10 t ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leguminous composted OAs @ 20 t ha−1 performed substantially better in all the plant growth and yield parameters, and N uptake compared to 10 t ha−1”
t0“Chinese Cabbage”
Claim · model-written summary
The authors recommend applying non-leguminous amendments at 10 t ha−1.
- Taxon
- Chinese CabbageBrassica rapa subsp. pekinensist0
- Outcome
- non-leguminous OAs should be applied at 10 t ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Thus, non-leguminous OAs should be applied at 10 t ha−1.”
t0“Chinese Cabbage”
Claim · model-written summary
The authors recommend mucuna compost for nitrogen supply in Samoa and other tropical regions.
- Taxon
- Chinese CabbageBrassica rapa subsp. pekinensist0
- Outcome
- mucuna can be promoted to supply N for crop cultivatione0
- Setting
- Samoa, other Pacific Islands and tropical countriese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Therefore, mucuna can be promoted to supply N for crop cultivation in Samoa, other Pacific Islands and tropical countries”
t0“Chinese Cabbage”
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