Page 51 - EER-2-3

Explora: Environment
and Resource Maize–pigeon pea intercropping in Ghana

Table 4. Physicochemical properties of soil at the study site in Fumesua during the initial stage in 2022 and after 2 years of
cropping
Soil depth Chemical properties Physical properties
(cm) pH N (%) P (mg/kg) K (cmol (+)/kg) Mg (cmol (+)/kg) Ca (cmol (+)/kg) OC OM Sand Clay Silt Texture
(%) (%) (%) (%) (%) class
Initial soil parameters
0 – 20 6.50 0.26 49.15 0.21 0.69 1.35 1.11 1.98 82.10 8.89 9.01 Loamy
sand
20 – 40 6.02 0.13 33.04 0.15 0.67 0.82 0.75 1.21 73.43 10.88 15.69 Sandy
loam
Soil parameters in the pigeon pea alley after 2 years
0 – 20 6.37 0.39 48.42 0.20 0.80 2.25 2.11 3.11 81.99 8.99 9.02 Loamy
sand
20 – 40 6.22 0.45 30.94 0.21 0.80 1.12 1.75 2.25 73.00 11.00 16.00 Sandy
loam
Soil parameters in the sole maize after 2 years
0 – 20 6.48 0.26 48.05 0.23 0.59 1.25 0.81 0.98 81.90 8.90 9.20 Loamy
sand
20 – 40 6.12 0.13 33.34 0.15 0.55 0.83 0.80 0.21 74.03 10.80 15.17 Sandy
loam
Abbreviations: Ca: Calcium; K: Potassium; Mg: Magnesium; N: Nitrogen; OC: Organic carbon; OM: Organic matter; P: Phosphorus.

increased significantly to 2.25 cmol (+)/kg and 0.80 cmol (Table 5). In the MPP cropping system, the BCR under
(+)/kg, respectively. Moreover, OC and OM improved NF treatment was 2.16, demonstrating economic viability
to 2.11% and 3.11%, respectively, suggesting enhanced even under minimal input conditions. This suggests that
soil fertility under pigeon pea cropping. At a depth of incorporating pigeon pea, a nitrogen-fixing legume,
20 – 40 cm, the concentrations of N and P were 0.45% can reduce the need for chemical fertilizers by naturally
and 30.94 mg/kg, respectively. Ca slightly decreased to enhancing soil fertility. Under the HR treatment, the BCR
1.12 cmol (+)/kg, while Mg remained stable. Soil texture slightly decreased to 1.91, indicating that the additional
remained sandy loam, with 73% sand, 11% clay, and fertilizer cost does not proportionally increase economic
16% silt. returns. However, with FR fertilizer application, the
The soil properties in the NPP system after 2 years at BCR improved significantly to 2.81, highlighting the
the 0 – 20 cm depth showed that N remains constant at potential for maximized profitability when input levels are
optimized (Table 5).
0.26%, matching the initial soil values, while P slightly
decreased to 48.05 mg/kg. Ca measured 1.25 cmol (+)/kg In contrast, the NPP system presented a slightly
and OM declined to 0.98%, both lower than in the pigeon different trends. Under the NF treatment, the BCR was 2.04,
pea alley cropping, suggesting reduced organic input from demonstrating moderate economic returns with low input
maize. At a depth of 20 – 40 cm, N and P levels were 0.13% (Table 5). Interestingly, the BCR increased to 2.81 under
and 33.34 mg/kg, respectively, comparable to the initial soil the HR treatment, similar to the highest return observed
values. Ca and Mg levels were slightly lower than those in in the MPP system. This suggests that maize responds
the pigeon pea alley cropping, while OM content remained well to moderate fertilizer application, possibly due to
low at 0.21%. the alleviation of nutrient constraints that limit growth
and yield. However, under FR treatment application, the
3.6. Economic analysis BCR was reduced to 2.37, reflecting diminishing returns
The benefit–cost ratio (BCR) was employed for the at higher input levels (Table 5). This indicates that the NPP
economic analysis. The MPP cropping systems were system is less efficient in translating additional fertilizer
compared to NPP system under varying fertilizer levels into economic benefits than the MPP system (Table 5).
to assess resource optimization and profitability. BCR,
a key indicator of economic advantage, varied across 4. Discussion
cropping systems and fertilizer applications, reflecting The study highlights the crucial role of MPP intercropping
the relationship between input costs and yield benefits systems in addressing the productivity, sustainability,

Volume 2 Issue 3 (2025) 10 doi: 10.36922/EER025130026