Abstract
Studies have shown that despite the positive response of maize to nitrogen (N), phosphorus (P), and potassium (K), actual yields in the savanna agroecological zones (AEZs) of northern Ghana remain well below the potential even with N-P-K fertilizer application. In a two-year nutrient omission trial in 12 locations within the Sudan savanna and Guinea savanna AEZs of northern Ghana, we quantified maize yield increases resulting from addition of secondary and micronutrients from the NPK-only fertilization practice for maize production in the two AEZs. In both years, applying only NPK fertilizer resulted in average yields of 3.6 t ha − 1 and 2.5 t ha − 1 in the Guinea savanna and Sudan savanna AEZs, respectively. However, addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizers (“balanced” fertilization) resulted in an average of 60% and 64% yield increases over those of the NPK-only treatment in the Sudan savanna and Guinea savanna AEZs, respectively. Compared to balanced fertilization, omission of S, Zn, and B reduced grain yield by an average of ∼34%, ∼28%, and ∼14%, respectively. The combined data suggest that, even though secondary- and micronutrients are needed in small quantities by plants relative to N, P, and K, they have an enormous effect on crop productivity. Therefore, to ensure sustainably increased maize productivity in the savanna agroecological zones of northern Ghana, fertilizer recommendations should not be restricted to only NPK fertilizers but all limiting secondary- and micronutrients must be accounted for in a holistic and balanced fertilizer recommendation.
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Claims 8
Claim · model-written summary
NPK-only maize fertilization yielded an average 3.6 t ha − 1 in Guinea savanna.
- Treatment
- applying only NPK fertilizere0
- Outcome
- average yieldse0
- Value
- 3.6 t ha − 1e0
- Setting
- Guinea savannae0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applying only NPK fertilizer resulted in average yields of 3.6 t ha − 1 and 2.5 t ha − 1 in the Guinea savanna and Sudan savanna AEZs, respectively”
t0“maize”
Claim · model-written summary
NPK-only maize fertilization yielded an average 2.5 t ha − 1 in Sudan savanna.
- Treatment
- applying only NPK fertilizere0
- Outcome
- average yieldse0
- Value
- 2.5 t ha − 1e0
- Setting
- Sudan savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applying only NPK fertilizer resulted in average yields of 3.6 t ha − 1 and 2.5 t ha − 1 in the Guinea savanna and Sudan savanna AEZs, respectively”
t0“maize”
Claim · model-written summary
Adding S, Zn and B to NPK increased maize yield 60% over NPK only in Sudan savanna.
- Treatment
- addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizerse0
- Outcome
- yielde0
- Direction
- increasese0
- Value
- 60%e0
- Comparator
- NPK-only treatmente0
- Setting
- Sudan savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizers (“balanced” fertilization) resulted in an average of 60% and 64% yield increases over those of the NPK-only treatment in the Sudan savanna and Guinea savanna AEZs, respectively”
t0“maize”
Claim · model-written summary
Adding S, Zn and B to NPK increased maize yield 64% over NPK only in Guinea savanna.
- Treatment
- addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizerse0
- Outcome
- yielde0
- Direction
- increasese0
- Value
- 64%e0
- Comparator
- NPK-only treatmente0
- Setting
- Guinea savannae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“addition of sulfur (S), zinc (Zn), and boron (B) to the NPK fertilizers (“balanced” fertilization) resulted in an average of 60% and 64% yield increases over those of the NPK-only treatment in the Sudan savanna and Guinea savanna AEZs, respectively”
t0“maize”
Claim · model-written summary
Omitting S from balanced fertilization reduced maize grain yield by about 34%.
- Treatment
- omission of Se0
- Outcome
- grain yielde0
- Direction
- reducede0
- Value
- ∼34%e0
- Comparator
- balanced fertilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to balanced fertilization, omission of S, Zn, and B reduced grain yield by an average of ∼34%, ∼28%, and ∼14%, respectively”
t0“maize”
Claim · model-written summary
Omitting Zn from balanced fertilization reduced maize grain yield by about 28%.
- Treatment
- omission of S, Zn, and Be0
- Outcome
- grain yielde0
- Direction
- reducede0
- Value
- ∼28%e0
- Comparator
- balanced fertilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to balanced fertilization, omission of S, Zn, and B reduced grain yield by an average of ∼34%, ∼28%, and ∼14%, respectively”
t0“maize”
Claim · model-written summary
Omitting B from balanced fertilization reduced maize grain yield by about 14%.
- Treatment
- omission of S, Zn, and Be0
- Outcome
- grain yielde0
- Direction
- reducede0
- Value
- ∼14%e0
- Comparator
- balanced fertilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared to balanced fertilization, omission of S, Zn, and B reduced grain yield by an average of ∼34%, ∼28%, and ∼14%, respectively”
t0“maize”
Claim · model-written summary
The authors recommend accounting for all limiting secondary and micronutrients in maize fertilizer recommendations.
- Outcome
- all limiting secondary- and micronutrients must be accounted for in a holistic and balanced fertilizer recommendatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fertilizer recommendations should not be restricted to only NPK fertilizers but all limiting secondary- and micronutrients must be accounted for in a holistic and balanced fertilizer recommendation”
t0“maize”
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