Abstract
In paddy soils, excessive application of N fertilizer often results in substantial N losses due to low N utilization efficiency. However, this condition can be mitigated by enhancing soil organic carbon content. Two-year field experiment was carried out at Mkula Irrigation Scheme in Kilombero Valley, Tanzania with the aim of investigating the impact of Azolla, rice straw incorporation and reduced levels of nitrogen input from NPKS-containing fertilizers on N use efficiency, soil chemical properties and rice grain yield. Assuming that this technology will introduce a novel perspective to the research, shedding light on alternative and potentially more sustainable methods for nitrogen management in paddy soils, it will be particularly relevant in sub-Saharan Africa, where the annual cost of chemical fertilizers is expected to continue rising. The treatments involved absolute control, half dose N (50 kg N ha -1 ), full dose N (100 kg N ha -1 ), and combination of these N doses with PKS, dry Azolla (3.4 t ha -1 ) and rice straw (6.9 t ha -1 ) through omission approach. The soil of the experimental area was sandy clay loam in texture, very strongly acid (pH 4.8), normal electrical conductivity (0.06 dS m -1 ), low amounts of recorded organic carbon (1.35%), total nitrogen (0.33%), 0.68 mg kg −1 available P, exchangeable potassium (0.15 cmol (+) kg −1 ), calcium (0.19 mg kg −1 ) and sodium percentage (3.75%), with very low cation exchange capacity (1.6 cmol (+) kg −1 ). The results showed that combination of Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N. Azolla, being an effective biofertilizer, significantly contributes to nitrogen fixation and soil enrichment. Interestingly, this study demonstrates that co-application of Azolla, rice straw, and 50% reduced N is effective for achieving high rice yields, minimizing over-dependence on chemical N fertilizer, sustainable agricultural development, and environmental conservation.
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Claims 5
Claim · model-written summary
Combined Azolla, straw and full NPKS application produced higher rice grain yield.
- Taxon
- rice
Oryza sativae0 - Treatment
- Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1e0
- Outcome
- rice grain yielde0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combination of Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N”
Claim · model-written summary
The combination increased rice nitrogen uptake.
- Taxon
- riceOryza sativae0
- Treatment
- Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1e0
- Outcome
- nitrogen uptakee0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combination of Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N”
Claim · model-written summary
The combination improved agronomic nitrogen efficiency.
- Taxon
- riceOryza sativae0
- Treatment
- Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1e0
- Outcome
- agronomic efficiency of Ne0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“combination of Azolla, rice straw +100 kg N ha -1 + 30 kg P ha -1 + 30 kg K ha -1 + 20 kg S ha -1 resulted in higher rice grain yield, nitrogen uptake and agronomic efficiency of N”
Claim · model-written summary
Azolla significantly contributes to nitrogen fixation and soil enrichment.
- Taxon
- riceOryza sativat0
- Treatment
- Azollae0
- Outcome
- nitrogen fixation and soil enrichmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Azolla, being an effective biofertilizer, significantly contributes to nitrogen fixation and soil enrichment”
t0“rice”
Claim · model-written summary
Applying Azolla and straw with 50% less N achieves high rice yields.
- Taxon
- riceOryza sativae0
- Treatment
- Azolla, rice straw, and 50% reduced Ne0
- Outcome
- rice yieldse0
- Direction
- highe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“co-application of Azolla, rice straw, and 50% reduced N is effective for achieving high rice yields”
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