Abstract
Abstract Nitrogen and weeds are two important factors that influence the productivity of rainfed upland rice ( Oryza sativa L.) in tropical Asia. A low recovery of applied fertilizer N in rainfed uplands is generally associated with high nitrate leaching losses and weed interferences. Field experiments were conducted during the wet seasons of 2002 and 2003 at the research farm of Central Rainfed Upland Rice Research Station, Hazaribag, Jharkhand, India, to determine the response of upland rice to nitrogen applied at 60 kg N ha –1 as different forms of urea (single pre‐plant application of controlled‐release urea, single pre‐plant application of urea supergranules, and split application of prilled urea with or without basal N) against no N application under three weed‐control regimes (unweeded, pre‐emergence application of butachlor at 1.5 kg a.i. ha –1 supplemented with one single hand weeding or two hand weedings). The response of rice to applied N varied greatly among the three weed‐control regimes. Across the different N treatments, the application of 60 kg N ha –1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha –1 in unweeded treatments, whereas yields increased by 1.07 Mg ha –1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha –1 with two hand weedings. Among the weed‐control measures, hand weeding twice produced highest grain yield in both years. The comparison of different forms of urea showed that a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha –1 compared to 1.32 and 1.30 Mg ha –1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively. The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea, suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled.
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Claims 9
Claim · model-written summary
Applying 60 kg N/ha increased grain yield by only 0.24 Mg/ha over the unfertilized control in unweeded plots.
- Taxon
- upland rice
Oryza sativat0 - Treatment
- 60 kg N ha –1e1
- Outcome
- grain‐yield increasee1
- Direction
- increasee1
- Value
- 0.24 Mg ha –1e1
- Qualifier
- in unweeded treatmentse1
- Comparator
- unfertilized controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Across the different N treatments, the application of 60 kg N ha –1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha –1 in unweeded treatments, whereas yields increased by 1.07 Mg ha –1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha –1 with two hand weedings”
t0“the productivity of upland rice”
Claim · model-written summary
Applying 60 kg N/ha increased grain yield by 1.07 Mg/ha over the unfertilized control when butachlor was supplemented with one hand weeding.
- Taxon
- upland riceOryza sativat0
- Treatment
- 60 kg N ha –1e1
- Outcome
- yieldse1
- Direction
- increasede1
- Value
- 1.07 Mg ha –1e1
- Qualifier
- butachlor application was supplemented with a single hand weedinge1
- Comparator
- unfertilized controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Across the different N treatments, the application of 60 kg N ha –1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha –1 in unweeded treatments, whereas yields increased by 1.07 Mg ha –1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha –1 with two hand weedings”
t0“the productivity of upland rice”
Claim · model-written summary
Applying 60 kg N/ha increased grain yield by 1.28 Mg/ha over the unfertilized control with two hand weedings.
- Taxon
- upland riceOryza sativat0
- Treatment
- 60 kg N ha –1e1
- Outcome
- yieldse1
- Direction
- increasede1
- Value
- 1.28 Mg ha –1e1
- Qualifier
- with two hand weedingse1
- Comparator
- unfertilized controle1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Across the different N treatments, the application of 60 kg N ha –1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha –1 in unweeded treatments, whereas yields increased by 1.07 Mg ha –1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha –1 with two hand weedings”
t0“the productivity of upland rice”
Claim · model-written summary
Hand weeding twice gave the highest grain yield in both years among the weed-control measures.
- Taxon
- upland riceOryza sativat0
- Treatment
- hand weeding twicee2
- Outcome
- grain yielde2
- Direction
- higheste2
- Qualifier
- in both yearse2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“Among the weed‐control measures, hand weeding twice produced highest grain yield in both years”
t0“the productivity of upland rice”
Claim · model-written summary
In 2002, a single pre-plant application of controlled-release urea gave higher average grain yield (1.57 Mg/ha) than split-applied prilled urea.
- Taxon
- upland riceOryza sativat0
- Treatment
- single pre‐plant application of controlled‐release ureae3
- Outcome
- average grain yieldse3
- Direction
- higherinferrede3
- Value
- 1.57 and 1.87 Mg ha –1e3
- Comparator
- split‐applied prilled ureae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha –1 compared to 1.32 and 1.30 Mg ha –1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively”
t0“the productivity of upland rice”
Claim · model-written summary
In 2003, a single pre-plant application of controlled-release urea gave higher average grain yield (1.87 Mg/ha) than split-applied prilled urea.
- Taxon
- upland riceOryza sativat0
- Treatment
- single pre‐plant application of controlled‐release ureae3
- Outcome
- average grain yieldse3
- Direction
- higherinferrede3
- Value
- 1.87 Mg ha –1e3
- Comparator
- split‐applied prilled ureae3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha –1 compared to 1.32 and 1.30 Mg ha –1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively”
t0“the productivity of upland rice”
Claim · model-written summary
Controlled-release urea gave the highest agronomic N use efficiency, 15–20 kg grain per kg N applied.
- Taxon
- upland riceOryza sativat0
- Treatment
- controlled‐release ureae4
- Outcome
- agronomic N use efficiencye4
- Direction
- higheste4
- Value
- 15–20 kg grain per kg N appliede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea”
t0“the productivity of upland rice”
Claim · model-written summary
Controlled-release urea gave the highest apparent N recovery, 39%–45%.
- Taxon
- upland riceOryza sativat0
- Treatment
- controlled‐release ureae4
- Outcome
- apparent N recoverye4
- Direction
- higheste4
- Value
- 39%–45%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea”
t0“the productivity of upland rice”
Claim · model-written summary
Controlled-release urea is particularly beneficial for upland rice cultivation under variable rainfall, provided weeds are controlled.
- Taxon
- upland riceOryza sativat0
- Outcome
- beneficial for upland‐rice cultivatione5
- Qualifier
- under variable rainfall conditions, provided weeds are controllede5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled”
t0“the productivity of upland rice”
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