2014 to the long rains in 2016. ⢠The treatments were: Sole Potato and Potato intercropped with either lablab (Dolichos lablab), garden pea (Pisum sativum) or ...
WATER USE EFFICIENCY AND YIELD OF POTATO IN POTATO-LEGUME BASED INTERCROPPING SYSTEMS IN A SEMI-HUMID REGION, KENYA Gitari H. I., Gachene C., Karanja N., Schulte-Geldermann E. (Nairobi, Kenya)
Introduction • Potato is an important food security crop in Kenya mainly cultivated under unpredictable rain fed conditions. • Given that the crop is very sensitive to drought conditions various methods have been proposed to enhance water use efficiency. They included: increased fertilization, plastic film and mulching. • Advantages and disadvantages. • Can cover crops be used instead?
• Aim : Identify a potato-legume intercropping system that is efficient in water utilization and still upholding optimum potato yield.
Materials and Methods The experiment was laid in RCBD with 4 replicates at UoN for 4 seasons from short rains of 2014 to the long rains in 2016. The treatments were: Sole Potato and Potato intercropped with either lablab (Dolichos lablab), garden pea (Pisum sativum) or climbing bean (Phaseolus vulgaris). Plots measured 4 x 6 m and data collection done from the central 2 by 3m quadrants
SMC and cover were determined fortnightly using HSM 50 soil moisture meter and sighting frame, respectively. ET (m3) = P + I ± 𝛥S RO – DD.
WUE (kg/ha/m3) = Y / (ET * 10)
Data Analysed using R Software, version 3.2.3 and means separated using Tukey’s post hoc test.
Results Among the potato legume plots, D. Lablab had the highest ground cover
Results Weather conditions ET (mm)
Rainfall (mm)
Tmax (°C)
Tmin (°C)
30
500
Rainfall and ET (mm)
35
25
400
20 300
15 200
10
100
5
0
0 Oct Nov Dec Jan Feb Mar Apr May Jun
2014 Short Rains
2015 Long Rains
Oct Nov Dec Jan Feb Mar Apr May Jun
2015 Short Rains
2016 Long Rains
Temperature (oC)
600
Results
PD
PS
S1 S2 S3 S4
-1.5
-0.5 0.0
0.5
Axis 1 (33.9%)
1.0
1.5
1.0 -0.5 0.0 0.5
PP
PB PD PP PS
S4 S3 S2
S1 S1 S2 S3 S4
-1.5
Axis 2 (29.0%)
-0.5 0.0 0.5
PB
-1.5
Axis 2 (29.0%)
1.0
PB PD PP PS
-1.5
-0.5 0.0
0.5
Axis 1 (33.9%)
Projection of the cropping systems and seasons on PCA1/2
1.0
1.5
80
Sole potato
Ground cover Potato & Lablab
Potato & G.Peas
Potato & Bean
Crop Cover (%)
60
40
20
0 0 14 28 42 56 70 84 Short Rains 2014
0 14 28 42 56 70 84
0 14 28 42 56 70 84
Long Rains 2015
Days after planting
Short Rains 2015
0 14 28 42 56 70 84 Long Rains 2016
Soil moisture content Soil Water Content (mm)
100
Sole Potato
Potato & Dolichos
Potato & G.Peas
0 14 28 42 56 70 84
0 14 28 42 56 70 84
Potato & Bean
80
60
40
20 0 14 28 42 56 70 84 2014 Short Rains
2015 Long Rains
Days After Planting
2015 Short Rains
0 14 28 42 56 70 84 2016 Long Rains
Fresh/dry matter tuber yield, cumulative dry matter yield, ET and WUE. Treatment
Fresh Dry tuber yield matter tuber (t ha-1) yield
Total DMY Evapotrans Water use (t ha-1) piration ( efficiency -1 m3) mm) (kg ha Potato & legumes
(t ha-1) Potato
36.8 c
6.5 c
8.7 a
575 a
1.6 a
Potato + Dolichos
34.5 c
6.2 c
17.9 d
626 b
3.0 d
Potato + G. pea
24.6 a
4.4 a
13.5 b
618 b
2.3 c
Potato + Bean
30.5 b
5.4 b
16.0 c
622 b
2.7 b
Relationship Between Variables 90
800
Y= 0.72x + 25.79 R² = 0.32***
70
600
ET (mm)
SMC (mm)
80
60
Y = 8.64x + 82.99 R² = 0.43***
400
50 40
200
30 20
a
40 Cover (%)
60
40
50
60
70
b SMC (mm)
80
Relationship Between Variables… 5
20
4
DMY (t ha-1)
WUE (kg ha-1 m-3)
Y = -0.003x + 3.90 R2 = 0.30***
3
15
10 2
DMY = 0.01x + 6.45 R² = 0.25*** 5
1 200
400 ET (mm)
600
800
200
400
ET (mm)
600
800
Conclusion The study demonstrates the practicality of intercropping potatoes with legume cover crops. Dolichos lablab was the best in cover development and soil moisture conservation, competing less with potato for water enhancing water WUE and potato productivity. Further study on spatial and temporal arrangements of the components crops. Upscaling is also recommended.
