Pathways to sustainable intensification of the coffee-banana agroecosystems in the Mt. Elgon region

Figures & data

Figure 1. (a) Location of the study area in Uganda, Mt. Elgon region, (b) elevation map of the Mt. Elgon region and (c) land cover map of the Mt. Elgon region.

Table 1. Selected variables for intensification land management pathway characterisation

Variable	Description	Extent of variable data collection and variable measurement
Total value of farm equipment (Shillings)	Value of farm investment in production equipment	Current value of farm equipment such as hand hoes, secateurs, forks, spades, wheel barrows was captured and valued in Uganda shillings
Total investment in water and soil conservation structures	Cost (Uganda Shillings) of constructing water and soil erosion conservation structures on the farm	Both annual hired and family labour used for making trenches, terraces, grass bunds, stone bunds, and mulching to prevent soil erosion and or increase fertility in the coffee banana garden were valued in Uganda shillings
Coffee output kgha^−1	Coffee yield	Coffee parchment was used as a standard measure of output. Red fresh cherries were converted to parchment equivalent in kg. This was converted to kgha^−1
Banana output kgha^−1	Banana yield	Modal banana bunch weight(Weight of majority of the bunches harvested in the last year) in kg as a unit of measure for its accuracy as used by Bagamba (2007) and Van Asten et al. (2011) were the measure of banana weight. Bananas harvested and converted to kgha^−1.
Rate of manure application (kgha^−1)	Rate (kgha^−1) of poultry and or cow manure used in the last one year	Manure was captured as spades, wheel barrows and lorries that was converted to kg equivalents. It was later converted to kgha^−1 as a unit area measure.
Rate of fertilizer application (kgha^−1)	Rate (kgha^−1) of fertilizer used in the last one year	Total fertilizer used on coffee-banana plots was recorded and converted to kgha^−1
Total tropical livestock units	Total tropical livestock units (TLUs)	The standard TLU formulae was used for the owned livestock by the household on farm; Tropical livestock unit (TLU): sum of the animals with loading; cow = 0.7/goat = 0.1/chicken = 0.01/pigs = 0.2/sheep = 0.1.
Percentage of fallow land cover (%)	Percentage of total farmland area under fallow	Uncultivated fallow land within the coffee banana plantation was estimated from farmer recalls per plot and recorded in hectares. A percentage was then calculated from the total coffee-banana farmland.
Percentage of shade tree land cover (%)	Percentage of total farmland area under shade trees	The area of land under shade trees within the coffee banana plantation was estimated from farmer recalls per plot and recorded in hectares. A percentage was then calculated from the total coffee-banana farmland.
Farmer perception of soils and biodiversity conservation on the farm (index)	Farm index score on a scale of six questions related to intentional conservation efforts on the farm	Farm index score on a scale of six questions related to intentional conservation efforts on the farm were asked. An index was calculated as a ratio of the number of affirmative questions a farmer answers out of six. Questions scored included: whether a farmer Minimises environmental impacts on farm, Looks after the environment, Improves resource/land/soil condition/fertility, Conserves diversity of animals/plants and ecosystems on farm, etc.
Coffee output per man-hour of labour (family and hired) (kg/man-hr)	Family and hired labour productivity in coffee	Labour was recorded for all production activities in coffee per year. The total coffee output (kg) was later divided by the total labour (man-hours)
Banana output per man-hour of labour (family and hired) (kg/man-hr)	Family and hired labour productivity in banana	Labour was recorded for all production activities in banana production annually. The total banana output (kg) was later divided by the total labour (man-hours)

Table 2. Summary statistics of independent variables used in PCA and cluster analysis

	Clusters (Mean (Std. dev))
Variable	Pooled sample (n = 453)	C1 (n = 120)	C2 (n = 210)	C3 (n = 48)	C4 (n = 75)
Total value of farm equipment (Uganda shillings)	134,256.98 (126,180.57)	113,238.07***^C2 (68,764.79)	237,108.04***^C4 (244,458.09)	117,380.65***^C2 (71,260.59)	157,694.12*^C4 (167,777.86)
Total investment in water and soil conservation structures (Uganda shillings)	88,648.13 (84,340.51)	84,977.23**^C3 (87,215.64)	95,588.75 (69,431.46)	134,526.55*^C4 (90,337.83)	65,157.90 (48,607.29)
Coffee output (kgha^−1)	2,353.16 (5,137.19)	1,157.59***^C4 (272.01)	2,337.58***^C4 (1,732.20)	1,523.32***^C4 (1,600.89)	9,606.10 (12,286.57)
Banana output (kgha^−1)	6,344.41 (5,342.80)	6,175.50 (5,258.43)	7,719.79 (5,642.12)	6,106.27 (5,144.91)	5,940.98 (5,581.18)
Rate of manure application (kgha^−1)	1,249.235 (1,267.338)	1,124.77**^C3 (1,118.72)	1,502.74 (1,416.07)	1,990.49 (1,804.05)	1,151.63 (1,402.17)
Rate of fertilizer application (kgha^−1)	123.29 (152.67)	70.47***^C2 (65.1292)	273.28***^C3 (229.04)	76.13 (48.57)	91.07***^C2 (82.15)
Total tropical livestock units	3.82 (3.66)	1.58***^C2 (1.49)	7.10***^C3 (13.84)	2.00 (1.53)	1.78***^C2 (1.98)
Percentage of fallow land cover (%)	7.24 (8.03)	2.66***^C3 (2.37)	5.49***^C3 (5.46)	17.48***^C4 (7.19)	6.67*^C1 (8.55)
Percentage of shade tree land cover (%)	2.22 (1.99)	2.14 (2.02)	2.25 (1.82)	2.59 (2.65)	2.46 (1.41)
Farmer perception on soils and biodiversity conservation on farm (index)	0.66 (0.33)	0.66 (0.37)	0.66 (0.21)	0.72 (0.19)	0.65 (0.29)
Coffee output per man-hour of labour (family and hired) (kg/man-hr)	0.84 (0.99)	0.54***^C2 (0.59)	1.11***^C4 (1.08)	0.95**^C1 (0.73) ***^C4	3.18***^C1 (1.04)
Banana output per man-hour of labour (family and hired) (kg/man-hr)	8.15 (7.58)	7.61 (7.50)	9.94 (8.13)	8.15 (9.33)	9.69 (6.03)

Significance:*10%, **5%, ***1%.

Tropical livestock unit (TLU): sum of the animals with loading; cow = 0.7/goat = 0.1/chicken = 0.01/pigs = 0.2/sheep = 0.1.; 1US$ = 3,342 Uganda Shillings (20 September 2016) at time of this study survey

Table 3. Principal components analysis Verimax rotated components

Variable	Comp1	Comp2	Comp3	Comp4	Comp5	Comp6	Comp7	Unexplained
Tropical livestock units (TLU)	0.012	0.031	0.646	0.169	0.319	−0.107	0.023	0.336
Total investment in soil and water conservation (Uganda shillings)	0.572	−0.065	0.101	0.143	−0.040	0.133	0.058	0.400
Percentage of shade tree land cover	−0.001	0.001	−0.002	0.004	0.002	−0.004	−0.002	0.001
Percentage of fallow land cover	0.005	−0.013	0.028	0.893	0.050	0.007	−0.004	0.124
Farmer perception on the conservation of soils and biodiversity on the farm (index)	−0.003	−0.001	−0.007	−0.002	−0.000	−0.003	0.990	0.011
Coffee output per man-hour of labour (family and hired)	−0.090	0.686	−0.051	0.200	−0.000	−0.019	0.022	0.325
Banana output per man-hour of labour (family and hired)	0.613	0.013	−0.111	−0.001	0.068	−0.078	−0.101	0.347
Coffee output (kgha^−1)	0.079	0.721	0.048	−0.195	−0.010	0.033	−0.021	0.291
Banana output (kgha^−1)	0.531	0.063	0.014	0.220	−0.050	−0.053	0.063	0.386
Total fertilizer (kgha^−1)	−0.002	0.007	−0.002	0.005	0.025	0.977	−0.004	0.033
Total manure (kgha^−1)	0.000	−0.007	−0.027	0.053	0.913	0.036	−0.002	0.121
Total farm equipment value (Shillings)	−0.018	−0.016	0.744	0.156	−0.228	0.065	−0.031	0.267
Eigenvalues	1.955	1.307	1.278	1.063	1.004	1.003	1.002
Cumulative explained Variance	14%	25%	35%	44%	53%	61%	70%

The Kaiser-Meyer-Olkin measure of sampling adequacy for this data was 0.60

Table 4. Final cluster centres for four clusters identified through K-means clustering

		Cluster
Principal components	Description	1 (Low agroecological)	2 (highly conventional)	3 (highly agroecological)	4 (mildly agroecological)
PC1	Soils and banana output	−0.219	0.447	1.436	−0.126
PC2	Coffee labour and output	−0.367	−0.059	−0.126	2.354
PC3	Farm equipment and livestock)	−0.225	1.212	−0.08	−0.144
PC4	Land fallow coverage (%)	−0.290	−0.080	2.769	0.160
PC5	Manure and shade trees	−0.184	0.958	0.252	−0.271
PC6	Fertilizer	0.001	0.016	0.174	−0.131
PC7	Soil and water conservation on farm	−0.253	1.334	−0.233	−0.042
Variable ranges	Mineral fertilizer range (min-max/kgha^−1)	0.627–286.622	6.351–1,093.344	14.074–173.883	5.810–361.705
	Manure range (min-max/kgha^−1)	1.555–8,465.608	2.045–39,950.060	2.524–12,012.010	2.263–5,198.181
	Shade tree coverage range % (min-max)	0.017–21.667	0.050–15.00	0.333–14.167	0.500–20.00
	Fallow land range % (min-max)	0.033–10.000	0.033–16.667	5.000–45.555	0.833–33.33

Figure 2. Dendrogram of clusters of coffee-banana farms based on intensification.

Figure 3. Boxplots showing: (a) Coffee yield variation by elevation and cluster, (b) coffee yield by variety and cluster, (c) coffee yield by elevation and variety and (d) banana yield by elevation and cluster.

Figure 4. Authors’ illustration of the distribution of the SI land management clusters on the mountain landscape at three altitude ranges.

Figure 5. Percentage of farms in each cluster by study sites.

Figure 6. Location of clusters by the distance from the national park boundary.

Table 5. Intensification factors affecting coffee yield based on gamma distributed GLM with log link

	Estimate	Std. Err.	z	p value
Intercept	0.70	1.90	0.37	0.71
Total fertilizer (kgha^−1)	0.0019	0.00084	2.29	0.02
Total manure (kgha^−1)	0.000011	0.000028	0.37	0.71
Percentage of shade tree land cover (%)	0.0041	0.028	0.15	0.88
Percentage of fallow land cover(%)	−0.02	0.017	−1.09	0.28
Tropical livestock units (TLU)	−0.00072	0.011	−0.07	0.95
Coffee output per man-hour of labour (family and hired)	0.04	0.038	1.02	0.31
Clusters
2 (highly conventional)	0.022	0.22	0.11	0.92
3 (highly agroecological)	0.27	0.44	0.61	0.54
4 (mildly agroecological)	1.03	0.33	3.11	0.002
Coffee variety
SL28	5.47	2.46	2.23	0.03
KP162	7.55	6.74	1.12	0.26
Bugisu local	4.82	2.07	2.33	0.02
Farmer inter-planted fodder trees in banana and coffee (dummy)	0.30	0.18	1.69	0.09
Elevation	0.0039	0.0012	3.11	0.002
Elevation: variety SL28	−0.0036	0.0016	−2.33	0.02
Elevation: variety KP162	−0.0049	0.0045	−1.1	0.27
Elevation: variety Bugisu local	−0.0029	0.0013	−2.24	0.03

Coffee yields by elevation: Elevation_1(1000–1500 masl)***^2,3 (mean = 967.51, sd = 1,132.03); elevation_2(1500–2000 masl)(mean = 1,488.40,sd = 1,409.61); elevation_3(>2000 masl)(mean = 1,991.27, sd = 1,659.37)**²: Bonferroni one way test significance between two elevations; ** = 5%, *** = 1%

Null deviance is 91.81 on 138° of freedom & the residual deviance is 82.60 on 121° of freedom; AIC = 17.51; BIC = −505.26; sd = standard deviation

Table 6. Intensification factors affecting banana yield based on gamma distributed GLM (log link)

	Coef.	Std. Err.	z	p > z
Intercept	6.81	0.70	9.72	0.00
Total fertilizer (kgha^−1)	0.00071	0.00057	1.24	0.22
Total manure (kgha^−1)	0.000015	0.00002	0.75	0.45
Banana output per man-hour of labour (family and hired)	0.0029	0.0014	2.09	0.037
Percentage of fallow land cover	−0.01	0.017	−0.60	0.55
Percentage of shade tree land cover	0.045	0.017	2.68	0.01
Tropical livestock units (TLU)	0.028	0.019	1.46	0.14
Cluster
2 (highly conventional)	0.18	0.21	0.83	0.41
3 (highly agroecological)	1.84	0.33	5.62	0.00
4 (mildly agroecological)	0.58	0.18	3.13	0.002
Farmer inter-planted fodder trees in banana and coffee(dummy)	1.70	0.86	1.99	0.047
Elevation	0.0011	0.0004	2.74	0.006
Elevation: farmer inter-planted fodder trees in banana and coffee	−0.00105	0.0005	−2.1	0.035

Null deviance is 517.20 on 452° of freedom and the residual deviance is 554 on 440° of freedom; AIC = 20.31; BIC = −2173.79

Table 7. Spearman’s correlation matrix

	Household size	Elevation	Age of household head	Farmer sex (1 = male,0 = female)	Credit access (dummy)	Number of coffee and banana plots	Farmer has an off-farm job	Farmer has planted windbreaks on farm (dummy)	Tropical Livestock units(TLU)	Total annual hired labour (man-hours)
Household size	1.00
Elevation	0.13*	1.00
Age of household head	0.20*	−0.13*	1.00
Farmer sex (1 = male, 0 = female)	−0.01	−0.05	−0.02	1.00
Credit access (dummy)	0.06	0.02	−0.10*	0.01	1.00
Number of coffee and banana plots	0.14*	−0.06	0.06	0.16*	0.08	1.00
Farmer has an off-farm job	0.01	0.05	−0.07	−0.07	−0.03	−0.08	1.00
Farmer has planted windbreaks on-farm	0.07	0.08	0.00	−0.00	0.02	0.23*	−0.04	1.00
Tropical livestock units (TLU)	0.34*	0.07	0.17*	0.02	−0.07	0.07	0.02	0.11*	1.00
Total annual hired labour(man-hours)	0.03	0.17*	0.04	−0.01	−0.05	0.35*	−0.06	0.09	0.04	1.00

Significance: *5%

Table 8. Estimates for the adoption of coffee-banana intensification pathways by multinomial logistic regression

	C2 (highly conventional)			C1 (low agroecological)			C 3a (highly agroecological)
Variables	β	Std. error	z value	β	Std. error	z value	β	Std. error	z value
Household size	−0.100	0.064	−1.580	0.100	0.064	1.580	0.036	0.067	0.540
Elevation	0.003***	0.001	3.760	−0.003***	0.001	−3.760	0.001	0.001	1.480
Age of household head	−0.011	0.012	−0.910	0.011	0.012	0.910	0.024	0.016	1.540
Farmer sex (1 = male, 0 = female)	0.187	0.326	0.570	−0.187	0.326	−0.570	−0.395	0.414	−0.950
Credit access (dummy)	−0.140	0.324	−0.430	0.140	0.324	0.430	1.066**	0.423	2.520
Number of coffee and banana plots	0.134**	0.053	2.530	−0.134**	0.053	−2.530	0.160***	0.055	2.930
Farmer has an off-farm job	0.404	0.318	1.270	−0.404	0.318	−1.270	−0.012	0.406	−0.030
Farmer has planted windbreaks on farm	−0.431	0.343	−1.250	0.431	0.343	1.250	0.230	0.465	0.500
Tropical livestock units (TLU)	0.372***	0.068	5.460	−0.372***	0.068	−5.460	0.070	0.104	0.670
Total annual hired labour (man-hours)	−0.000	0.000	−0.010	0.000	0.000	0.010	−0.000	0.000	−0.530
Intercept	−6.561***	1.531	−4.290	6.561***	1.531	4.290	−7.295***	1.939	−3.760
	C3^b			C4^a (mildly agroecological)			C4^b
	β	Std. error	z value	β	Std. error	z value	β	Std. error	z value
Household size	0.137	0.086	1.590	−0.070	0.063	−1.110	0.030	0.082	0.370
Elevation	−0.001	0.001	−1.340	0.001**	0.001	2.010	−0.001	0.001	−1.530
Age of household head	0.035*	0.019	1.890	−0.014	0.012	−1.210	−0.003	0.015	−0.220
Farmer sex (1 = male, 0 = female)	−0.582	0.495	−1.180	0.164	0.315	0.520	−0.023	0.413	−0.060
Credit access (dummy)	1.206**	0.498	2.420	0.024	0.312	0.080	0.164	0.408	0.400
Number of coffee and banana plots	0.026	0.057	0.460	0.052	0.065	0.800	−0.082	0.072	−1.140
Farmer has an off-farm job	(0.416)	0.480	−0.870	0.025	0.313	0.080	−0.379	0.405	−0.940
Farmer has planted windbreaks on farm	0.661	0.544	1.210	−0.478	0.326	−1.470	−0.047	0.427	−0.110
Tropical livestock units (TLU)	−0.302***	0.107	−2.810	0.107	0.089	1.200	−0.265***	0.091	−2.930
Total annual hired labour (man-hours)	−0.000	0.000	−0.530	−0.000	0.000	−0.260	(0.000)	0.000	−0.230
Intercept	−0.734	2.330	−0.310	−3.157**	1.378	−2.290	3.404*	1.901	1.790

Significance:*10%,**5%, ***1%.; Hausman test rules out a violation of IIA.

a The reference cluster is C1, b The reference cluster is C2(LR chi2(30) = 114.41; Prob>chi2 = 0.000)

Table 9. Effect of elevation on the independent variables used in PCA and cluster analysis

	Altitude range (masl)
	Elevation (1,000–1,500)			Elevation (1,500–2,000)			Elevation (>2,000)
	Mean	sd	Max	Mean	sd	Max	Mean	sd	Max
TLU	1.795	2.327	17.860	2.850	7.212	101.000	2.054	3.797	25.540
Total investment in soil and water management	119,914.300	181,658.100	1,207,525.000	173,313.400	322,606.800	2,643,000.000	149,918.000	208,366.100	1,037,000.000
Percentage shade tree land coverage	3.438	4.322	21.667	2.958	3.594	20.000	2.643	2.927	18.833
Percentage fallow land coverage	8.281	6.470	18.333	6.353	7.953	33.333	8.432	9.516	45.555
Farmer perception on soils and biodiversity conservation on farm (index)	0.661	0.240	1.000	0.657	0.395	5.500	0.672	0.203	1.000
Coffee output per labour man-hour	0.804	1.282	6.714	1.378	2.578	21.900	1.390	2.659	20.000
Banana output per labour man-hour	21.072	42.429	229.839	25.628	68.693	487.500	19.440	63.538	412.500
Coffee output (kgha^−1)	1,021.177	1,271.348	7,407.407	2,595.009	5,844.963	59,259.260	3,943.721	6,193.929	29,629.630
Banana output (kgha^−1)	10,900.880	27,076.060	204,360.500	12,032.400	21,136.370	231,604.900	11,435.670	15,423.170	87,481.480
Fertilizer rate (kgha^−1)	107.464	159.655	750.361	124.094	157.913	1,093.344	140.776	126.315	417.319
Manure rate (kgha^−1)	1,341.769	3,101.499	29,126.790	2,041.186	4,713.828	39,950.060	971.211	1,742.840	9,413.895
Total value of farm equipment (Uganda shillings)	100,772.900	59,153.550	400,000.000	212,857.300	455,772.200	4,728,000.000	193,123.900	271,935.800	1,602,000.000

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