Abstract
Maize is vital in Ethiopia, particularly in Jimma. However, the benefits of deficit irrigation (DI) under varying nitrogen rates (NRs) for maize remain unknown. A 3-year field experiment assessed maize response to different NRs (N0=0 kg ha−1, N23=23 kg ha−1, N46=46 kg ha−1, N69=69 kg ha−1, and N92=92 N kg ha−1) under three DI levels (I50=50, I75=75, and I100=100% ETc). Factors such as rain-fed findings, soil testing, and local recommendations were considered in determining these rates. The results showed significant effects of DI, NR, and their interactions on grain yield, biomass, water-use efficiency (WUE), nitrogen-use efficiency (NUE), and harvest index (HI). Without nitrogen, 50% DI led to a greater than 50% reduction in yield and biomass compared with that at I100×N0. However, WUE and HI increased at I50×N92 compared with I100×N0. Increasing irrigation and nitrogen levels improved yield and biomass. Optimal WUE was achieved with irrigation close to 75% ETc without compromising yields. Agronomic yield significantly improved with NR above 92 kg N ha−1 under mild deficit and full irrigation, but higher rates did not provide additional benefits under severe deficit conditions. The economically optimum nitrogen rate ranged from 78 to 80 kg N ha−1 for irrigation levels ranging from 50% to 100% ETc. The study suggests that applying 80 kg N ha−1 with 75%–100% ETc levels is the best approach to enhance maize yield and achieve economic benefits. Further research is needed to explore DIs below 50% and above 100% ETc, as well as nitrogen fertilization rates above 92 kg ha−1, in order to optimize maize production in the region.
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Claims 10
Claim · model-written summary
Deficit irrigation, nitrogen rate and their interactions had significant effects on maize grain yield and biomass.
Zea maysNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e1“significant effects of DI, NR, and their interactions on grain yield, biomass, water-use efficiency (WUE), nitrogen-use efficiency (NUE), and harvest index (HI)”
Claim · model-written summary
Deficit irrigation, nitrogen rate and their interactions had significant effects on maize water-use efficiency, nitrogen-use efficiency and harvest index.
- Treatment
- DI, NR, and their interactionse1
- Outcome
- water-use efficiency (WUE), nitrogen-use efficiency (NUE), and harvest index (HI)e1
- Setting
- Southwest Ethiopiat1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e1“significant effects of DI, NR, and their interactions on grain yield, biomass, water-use efficiency (WUE), nitrogen-use efficiency (NUE), and harvest index (HI)”
Claim · model-written summary
Without nitrogen, 50% deficit irrigation reduced maize yield and biomass by more than 50% compared with full irrigation at N0.
- Treatment
- 50% DIe2
- Outcome
- yield and biomasse2
- Direction
- reductione2
- Value
- greater than 50%e2
- Qualifier
- Without nitrogene2
- Comparator
- I100×N0e2
- Setting
- Southwest Ethiopiat1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e2“Without nitrogen, 50% DI led to a greater than 50% reduction in yield and biomass compared with that at I100×N0”
Claim · model-written summary
At I50×N92, maize WUE and HI increased compared with I100×N0.
- Treatment
- I50×N92e3
- Outcome
- WUE and HIe3
- Direction
- increasede3
- Comparator
- I100×N0e3
- Setting
- Southwest Ethiopiat1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e3“However, WUE and HI increased at I50×N92 compared with I100×N0”
Claim · model-written summary
Increasing irrigation and nitrogen levels improved maize yield and biomass.
- Treatment
- Increasing irrigation and nitrogen levelse4
- Outcome
- yield and biomasse4
- Direction
- improvede4
- Setting
- Southwest Ethiopiat1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e4“Increasing irrigation and nitrogen levels improved yield and biomass”
Claim · model-written summary
Optimal maize WUE was achieved with irrigation close to 75% ETc without compromising yields.
- Treatment
- irrigation close to 75% ETce5
- Outcome
- WUEe5
- Direction
- Optimale5
- Qualifier
- without compromising yieldse5
- Setting
- Southwest Ethiopiat1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e5“Optimal WUE was achieved with irrigation close to 75% ETc without compromising yields”
Claim · model-written summary
Agronomic yield of maize significantly improved with nitrogen rates above 92 kg N ha−1 under mild deficit and full irrigation.
- Treatment
- NR above 92 kg N ha−1e6
- Outcome
- Agronomic yielde6
- Direction
- significantly improvede6
- Qualifier
- under mild deficit and full irrigatione6
- Setting
- Southwest Ethiopiat1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e6“Agronomic yield significantly improved with NR above 92 kg N ha−1 under mild deficit and full irrigation, but higher rates did not provide additional benefits under severe deficit conditions”
Claim · model-written summary
Higher nitrogen rates did not provide additional maize benefits under severe deficit conditions.
- Treatment
- higher ratese6
- Outcome
- additional benefitse6
- Direction
- did not providee6
- Qualifier
- under severe deficit conditionse6
- Setting
- Southwest Ethiopiat1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e6“Agronomic yield significantly improved with NR above 92 kg N ha−1 under mild deficit and full irrigation, but higher rates did not provide additional benefits under severe deficit conditions”
Claim · model-written summary
The economically optimum nitrogen rate for maize ranged from 78 to 80 kg N ha−1 across irrigation levels of 50% to 100% ETc.
- Outcome
- economically optimum nitrogen ratee7
- Value
- 78 to 80 kg N ha−1e7
- Qualifier
- for irrigation levels ranging from 50% to 100% ETce7
- Setting
- Southwest Ethiopiat1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e7“The economically optimum nitrogen rate ranged from 78 to 80 kg N ha−1 for irrigation levels ranging from 50% to 100% ETc”
Claim · model-written summary
Applying 80 kg N ha−1 with 75%–100% ETc irrigation is the best approach to enhance maize yield and achieve economic benefits.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Irrigated Maize Productivity”
t1“Southwest Ethiopia”
e7“The study suggests that applying 80 kg N ha−1 with 75%–100% ETc levels is the best approach to enhance maize yield and achieve economic benefits”
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