Abstract
Field experiments were conducted to study the effects of different proportions of controlled-release nitrogen fertilizer mixed with quick-acting nitrogen fertilizer on the yield and nitrogen utilization efficiency of direct-seeding rapeseed. Using a conventional nitrogen application rate of 180 kg ha−1 as a control, a total of 5 types of available nitrogen fertilizers and different proportions of controlled-release nitrogen fertilizers were mixed for fertilizer treatment. The proportion of available nitrogen fertilizer used was 135 kg ha−1, and the addition ratios of the five types of controlled-release nitrogen fertilizers were 0%, 30%, 50%, 70%, and 100%, respectively (i.e., the proportion of controlled-release nitrogen to the total nitrogen application amount). These ratios were represented as N135R0, N135R1, N135R2, N135R3, and N135R4, respectively. The results showed that there was no significant difference in the number of pods per plant, the number of seeds per pod, or the grain yield under the treatment of controlled-release nitrogen fertilizer mixed with quick-acting nitrogen fertilizer for proportions of 30–50% (N135R1~R3) when compared with the control, and a stable yield was achieved. Mixing controlled-release nitrogen fertilizer under reduced nitrogen application can significantly improve the apparent utilization rate of rapeseed nitrogen fertilizer, but it first increases and then decreases with the increase of the controlled-release nitrogen mixing ratio, reaching its highest under the N135R2 treatment. The agronomic utilization efficiency and partial productivity of nitrogen fertilizer first increased and then decreased with the increased proportion of controlled-release nitrogen, and both reached their highest utilization with the N135R2 treatment. The mixed treatment of controlled-release nitrogen did not affect soil urease activity, but significantly increased soil sucrase activity. The mixed treatment of controlled-release nitrogen also increased soil microbial biomass nitrogen and carbon content. Especially in the flowering stage, the soil microbial biomass nitrogen and carbon content was significantly higher under a controlled-release nitrogen mixing ratio of 30–50%. At the same time, it had a similar effect on soil inorganic nitrogen content. Therefore, a controlled-release nitrogen mixing treatment provided sufficient nitrogen for the key growth period of rapeseed. Under the condition of reducing the amount of nitrogen fertilizer by 25% based on the amount of nitrogen fertilizer applied to conventional rapeseed, the application of controlled-release urea mixed with common nitrogen fertilizer mixed at a ratio of 30–50% can be an effective way to maintain grain yield levels and improve nitrogen utilization efficiency.
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Claims 11
Claim · model-written summary
Mixed nitrogen fertilizer at 30–50% maintained pod number, seed number and grain yield relative to conventional nitrogen.
Verbatim
e0“there was no significant difference in the number of pods per plant, the number of seeds per pod, or the grain yield under the treatment of controlled-release nitrogen fertilizer mixed with quick-acting nitrogen fertilizer for proportions of 30–50% (N135R1~R3) when compared with the control, and a stable yield was achieved”
t0“Rapeseed”
Claim · model-written summary
Reduced nitrogen with controlled release fertilizer significantly improved apparent nitrogen utilization, peaking at N135R2.
- Taxon
- rapeseede0
- Treatment
- Mixing controlled-release nitrogen fertilizer under reduced nitrogen applicatione0
- Outcome
- apparent utilization rate of rapeseed nitrogen fertilizere0
- Direction
- improvee0
- Qualifier
- highest under the N135R2 treatmente0
Not reportedComparator
Verbatim
e0“Mixing controlled-release nitrogen fertilizer under reduced nitrogen application can significantly improve the apparent utilization rate of rapeseed nitrogen fertilizer, but it first increases and then decreases with the increase of the controlled-release nitrogen mixing ratio, reaching its highest under the N135R2 treatment”
Claim · model-written summary
Agronomic nitrogen utilization efficiency peaked at N135R2 after increasing then decreasing with mixing ratio.
Verbatim
e0“The agronomic utilization efficiency and partial productivity of nitrogen fertilizer first increased and then decreased with the increased proportion of controlled-release nitrogen, and both reached their highest utilization with the N135R2 treatment”
t0“Rapeseed”
Claim · model-written summary
Nitrogen fertilizer partial productivity peaked at N135R2 after increasing then decreasing with mixing ratio.
Verbatim
e0“The agronomic utilization efficiency and partial productivity of nitrogen fertilizer first increased and then decreased with the increased proportion of controlled-release nitrogen, and both reached their highest utilization with the N135R2 treatment”
t0“Rapeseed”
Claim · model-written summary
Mixed controlled-release nitrogen did not affect soil urease activity.
- Taxon
- Rapeseedt0
- Treatment
- mixed treatment of controlled-release nitrogene0
- Outcome
- soil urease activitye0
- Direction
- did not affecte0
Not reportedComparator
Verbatim
e0“The mixed treatment of controlled-release nitrogen did not affect soil urease activity”
t0“Rapeseed”
Claim · model-written summary
Mixed controlled-release nitrogen significantly increased soil sucrase activity.
- Taxon
- Rapeseedt0
- Treatment
- mixed treatment of controlled-release nitrogene0
- Outcome
- soil sucrase activitye0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“The mixed treatment of controlled-release nitrogen did not affect soil urease activity, but significantly increased soil sucrase activity”
t0“Rapeseed”
Claim · model-written summary
Mixed controlled-release nitrogen increased soil microbial biomass nitrogen and carbon.
- Taxon
- Rapeseedt0
- Treatment
- mixed treatment of controlled-release nitrogene0
- Outcome
- soil microbial biomass nitrogen and carbon contente0
- Direction
- increasede0
Not reportedComparator
Verbatim
e0“The mixed treatment of controlled-release nitrogen also increased soil microbial biomass nitrogen and carbon content”
t0“Rapeseed”
Claim · model-written summary
At flowering, 30–50% controlled-release nitrogen significantly increased soil microbial nitrogen and carbon.
- Taxon
- Rapeseedt0
- Organ / stage
- flowering stagee0
- Treatment
- controlled-release nitrogen mixing ratio of 30–50%e0
- Outcome
- soil microbial biomass nitrogen and carbon contente0
- Direction
- highere0
Not reportedComparator
Verbatim
e0“Especially in the flowering stage, the soil microbial biomass nitrogen and carbon content was significantly higher under a controlled-release nitrogen mixing ratio of 30–50%”
t0“Rapeseed”
Claim · model-written summary
Controlled-release nitrogen had a similar effect on soil inorganic nitrogen content.
Not reportedComparatorDirection
Verbatim
e0“At the same time, it had a similar effect on soil inorganic nitrogen content”
t0“Controlled-Release Nitrogen Mixed with Common Nitrogen Fertilizer Can Maintain High Yield of Rapeseed”
Claim · model-written summary
The authors concluded mixed controlled-release nitrogen supplied sufficient nitrogen during key rapeseed growth.
Verbatim
e0“a controlled-release nitrogen mixing treatment provided sufficient nitrogen for the key growth period of rapeseed”
Claim · model-written summary
The authors recommend 30–50% controlled-release urea with common fertilizer at 25% lower total nitrogen to maintain yield and improve use efficiency.
Verbatim
e0“Under the condition of reducing the amount of nitrogen fertilizer by 25% based on the amount of nitrogen fertilizer applied to conventional rapeseed, the application of controlled-release urea mixed with common nitrogen fertilizer mixed at a ratio of 30–50% can be an effective way to maintain grain yield levels and improve nitrogen utilization efficiency”
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