Power Point Experiences of Rainwater Harvesting For Food Security in Marigat1 District

Experiences of Rainwater Harvesting for Agricultural Production in

the Semi-Arid Marigat District, Kenya

WANJALA WANYONYI NASIREMBE 1 , PETER KUNDU MUSUYA2, CYRIAQUE RUFIN NGUIMALET3

1Kenya Agricultural Research Institute, P.O. Box 100, Molo,[email protected]

2Egerton University, PO Box 536, Njoro, Kenya, [email protected] of Bangui, Bangui, Central African Republic,

[email protected]

This Paper will be an oral Presentation in the area of,

“Strategies for coping with climate change”.

mailto:[email protected]



Abstract:

The region around Lake Baringo is inhabited by semi-nomadic

pastoralists of the Njemps Tugen, Turkana and Pokot ethnic groups

which mainly depend on livestock for their livelihood(Kaimba et

al.,2011). However, some crop production takes place. Rainfall is

erratic with an average of about 650mm/year. The main rainy

season starts from March to June. This study was conceived with

the idea of demonstrating various soil and water conservation for

crop development techniques which could be of value in combating

desertification and improving the economic base of the population

of this semi-arid region. Being on the lower side of Kamasia

hills, it is also faced by floods due to runoff and backflow from

Lake Baringo as the lake has no outlet. River Perkerra, which

feeds the lake, receives its water from East Mau Escarpment. The

experiment was set up neart the Marigat Airstrip Field belonging

to Kenya Agricultural Research Institute. In this study the

different water harvesting techniques for crop production were

put in use. Methods that were employed during the study were;

External catchment system, that gently delivered water to a

series of conservation structures; cropped basin, contour ridges,2

semi-circular loops and tied ridges under which pigeon peas,

cowpeas, wheat, and sorghum were tested for productivity. In the

completely randomized block design, the main plot was rain fed

and supplemental moisture source through a cut off drain. The

sub-plot was type(s) of water conservation structures and the

sub-sub plot were the crop types. Although some technically

promising results were obtained, there are still many

constraints. Inhabitants of the study area who should benefit

from this study generally did not accept the recommended

techniques as they were alien to their own experiences or culture

apart from the land ownership system that existed during the

study.

Keywords: Semi-nomadic pastoralists, water harvesting,

agricultural productivity, Marigat District, semi-arid Kenya.

Introduction

The Site near Marigat town lies 0.40N 360 E. It is elevated at

about 980-1200m above sea level. The area has a population of

6 661 (2009) which is projected to 7 259 today (Kenya National

Bureau of Statistics, 2009). The prevailing agro-ecological zone

is IV (Wetangula, et al., 2010) which gets severe as one approach

3

Marigat from Nakuru. The area is served by one perennial river,

Perkerra, Chemeron and two seasonal ones; Endao and Arabel (Fig.

1). The area also hosts the Chemeron dam, a project that has not

met its objectives (KVDA, 2004), due to siltation that has been

attributed to the storms, poor vegetation cover, stock type,

density and mode of livestock rearing. The area is inhabited by

semi-nomadic pastoralists of Pokot, Turkana, Tugen and Njemps

ethnic groups who all depend on livestock for their livelihood.

The soils have been described as young and fragile (Mwasi, 2001).

However, in places where runoff Strategies for coping with

climate change.is not destructive, soil conditions are favorable

for crop cultivation. Rainfall is erratic with an average of

about 650mm/year. The mean annual evaporation is estimated at 2,020

mm per year (JICA/MOARD, 1999).The main rain season is from March

to June. The rest of the year remains dry and windy drying the

ground bare though this situation has been partially mitigated by

the controversial prosopis trees (juliflora and gelinsis)

(Pasiecznik et al., 1995), withstands extreme aridity and goat

browsing in the Republic of Cape Verde. Nitrogen Fixing Tree Research

Reports, 13: 186-188.. The introduction of prosopis was meant to

alleviate livestock feed problem but the residents have seen more

hazards from it than benefits.

In many dry regions of the world, runoff farming was already an

important means of securing sufficient water for agricultural

crops or pasture areas two to three millennia ago. The runoff can

either be diverted directly and spread on the fields or collected4

Lake B aringo

Endao R iver

Lake BogoriaLake b aringo catchm rent.R iversshp.Lakes.Island.

200 0 200 400 K ilom eters

Study AreaK E N Y A

M arigat

S

N

EW

Lake B aringo C atchm ent w here M arigat lies

in some way to be used at a later time (Rosegrant et al., 2001).

The higher the aridity of an area, the larger is the required

catchment area in relation to the cropping area for the same

water yield (Prinz ,2002). On flat land 0-2% together with the

aridity of the location determines the catchment to the cropping

ratio (CCR), which varies from 1:1 to 5:1 Examples are given from

India (Vijayalakshmi et al., 1982) and the USA (Frasier 1994)

(Prinz 1996).The size of the catchment can be (in the case of

micro-catchment) rather small, in the case of macro-catchment and

floodwater it is relatively large and measures must be taken to

route the runoff to the collection area and to prevent

significant infiltration losses.

The statistical analysis revealed that when a suitable crop is

chosen and an appropriate water harvesting system applied under a

fence, yield can increase by up to 300%(1.53t/ha) though still

low compared to those from high potential areas(>5t/ha) in the

case of maize, can keep away food aid. This is one of the areas

in Kenya that have received food aid every year. The study was

conceived with the intention of demonstrating various soil and

5

Lake B aringo

Endao R iver

Lake BogoriaLake b aringo catchm rent.R iversshp.Lakes.Island.

200 0 200 400 K ilom eters

Study AreaK E N Y A

M arigat

S

N

EW

Lake B aringo C atchm ent w here M arigat lies

Figure Lake Baringo Catchment, Marigat and study area

water conservation practices for crop establishment in order to

mitigate desertification effects improve food security and

increase economic power of the local community. Unpredictable

extreme drought and flood in the area has necessitated great

interest in the context of climate change because most of African

communities would need to share those experiences for adoption in

the same conditions. Since land has not been extensively

adjudicated, livestock and crop interference often causes

conflict over meager natural resources. Ostriches for instance

often damage young crops.

Problem

Concerns of food security and water scarcity in the wake of

climate change are global and real particularly in Marigat, arid

areas of Kenya and the sub-Saharan Africa as a whole. As

communities struggle to adapt to the challenges of food

insecurity caused by climate change they are also sensitive to

the diminishing and management problems of resources. It is

anticipated that African countries in particular will endure some

6

of the worst effects of climate change by 2080 causing stress on

water resources and food production (CCAA, 2006).

Water sources in Marigat are rain, river and borehole. Water

scarcity for human and livestock consumption is a common problem

in the district. This is caused by prolonged droughts,

unpredictable rainfall patterns overstocking and uncoordinated

use of existing natural resources. The only perennial river is

Perkerra with a high discharge fluctuation capacity. During dry

periods, its water does not reach Lake Baringo. The little water

that crosses Marigat bridge is diverted and treatment for

domestic use within town and the environs. A significant portion

of the developed scheme farmland has been abandoned due to water

scarcity leading to poor crop performance. Perkerra river bank

erosion; the ever increasing meandering of the river just below

Marigat Bridge has adversely eroded the river banks thus

threatening the scheme intake works and the fields.

Materials and Methods

7

Two hectares of land near Marigat Airstrip were fenced off by a

chain link and divided into two parts, A and B. Tillage was done

before four water conservation structures were constructed. One

plot was rain fed only, the other had an external supplemental

water supply from a cut off drain which was graded at ≈2% so as

to reduce the effects of erosion. Treated seeds were planted

before the onset of rains. With identical experimental layout,

the two fields were planted with Maize, Pigeon peas, sorghum,

Cowpeas and Wheat. The crops were replicated four times in both

plots in a Completely Randomized Block Design under four

different moisture conservation structures. The amount of runoff

flow was controlled by a free board to allow excess water non-

destructive exit to protected area against erosion. The runoff

was trained to fill basins, straight ridges; tied ridges and

finally the semi-circular loops in that order. Effective rainfall

that occurred by physiological maturity of crops was 445mm with

60% as runoff. The rest of the rain occurs during a small peak in

August to October which accounts for the 200mm.

8

The wall wings of the semi-circular loops are constructed on the

same spirit level so as to balance the forces of water being held

by the loop while allowing it opportunity to infiltrate.

Table 1 Experimental layout

WaterRetentionStructure

Supplemented by cutoff runoff (Plot

A)Rain fed only (Plot B)

Basin Maize Sorghum

Cowpea

Pigeonpea

Wheat Maize Sorghu

mCowpea

Pigeonpea

Wheat

StraightRidges

Cowpea

Pigeonpea

Wheat

Sorghum

Maize

Cowpea

Pigeonpea

Wheat

Sorghum

Maize

TiedRidges

Pigeon pea

Cowpea

Maize

Sorghum

Wheat

Pigeon pea

Cowpea

Maize

Sorghum

Wheat

Semi-circularloops

Maize Sorghum

Wheat

Pigeonpea

Cowpea Maize Sorghu

mWheat

Pigeonpea

Cowpea

Weeding was every two weeks. Harvesting started after 2⅓ months

with wheat. In the case of cow pea, only the edible grains were

harvested and mass determined in each plot. Since several crops

were tested and had different values to the consumers, each was

analyzed against the water conservation structure without regard

to interactions.

9

Crops grown in the Basin bed

5m

10cm

3m

Basin

Basins used were mulched depressions dug into the earth 10cm deep

and used to receive water from the diversion drain for ponding to

offer opportunity for infiltration and make it available for

crops. Basins work best on a flat landscape as this allows for an

non destructive runoff (Figure2).

Contour Ridges

The main advantage of ridges is the greater accumulation of

rainwater within the furrows due to the retention of potential

runoff, Figure 3a and 3b.

10

Figure 1 Water Pans

Crops grown here

3-5m

3-5m

Concentration of water in the furrows encourages deeper

percolation, but for this to be useful to a crop, the soil's

available water holding capacity (AWC) must be sufficient to

retain the accumulated water within root zones (Optimizing Soil

Moisture for plant production). Sandy soils with a low AWC may permit a

large

proportion of the rainwater to drain beyond the zone penetrated

by the roots.

Thick clay loams of alluvial origin are found around Marigat and

are very erosive.

11

Figure 3a Contour ridges

Figure 3b Tied Contour ridges

Results and discussions

Table 1. Mean Crop Yield tons/ha

Cut off and rainfed

maize

maize

maize

pigeonpeas

pigeonpeas

pigeonpeas

sorghum

sorghum

sorghum

Cow peas

Cowpeas

Cowpeas

wheat

wheat

wheat

Basin

1.5

3

1.5

2

1.5

6

1.7 1.5 1.9 1 0.8 1.2 0.

1

0.1

2

0.1

5

1.3 1.4 1

Straightridges

0.7 0.8 1.1 1.2 1.2 1.5 1.9 2.3 1.5 0.

23

0.3

2

0.3

1

0.4 0.5 0.

6

Tiedridges

1.2 1.1 1.1 2 2.1 1.8 0.9 0.8 1.2 0.

19

0.1

9

0.2

1

0.8 0.7 0.

9

Semi-circularloops

1.3 1 1.4 2.8 2.7 3.2 2.1 2 1.4 0.

4

0.6 0.5 1.5 1.9 1.

4

Rain fed onlyBasin

1.1 0.8 1.1 0.6 0.7 0.9 0.4 0.4 0.8 0.

8

0.7 0.9 0.7 0.8 0.

9

Straight

0.6 0.5 0.6 0.7 0.9 0.8 1.3 1.7 1.4 0. 0.1 0.1 0.1 0.1 0.

12

Figure 4 Semi-circular loops

ridges

12 3 4 2 7 15

Tiedridges

0.8 0.9 0.7 0.9 0.8 0.8 0.8 0.9 1.1 0.

15

0.1

9

0.1

7

0.4 0.5 0.

6

Semi-circularloops

0.5 0.6 0.4 1.2 1.4 0.9 0.3 0.2 0.4 0.

25

0.2

3

0.3

5

0.1

6

0.1

9

2.

1

The data was found not to be normally distributed. It was also

found not to be homogenous. In this case, the effect of soil and

water conservation structures was analyzed per crop also yields

for different crops could not be compared using yield alone.

A two-way ANOVA was used separately to identify the differences

between cutoff systems and its interactions with different

conservation structures. It was observed that there existed a

significant difference between rain fed and runoff supplemented

field by water from a cut off drain at p≤0.05 in total yield.

Table 2 Effect of source of water to crop yield

13

Source of water

Yield t/Ha

Cut off Drain

1.161A

Rain fed 0.677B

Means with the same letter are not significantly different at

p≤0.05 using lsd.

Difference in means could be attributed to the infiltration rate

which may have inhibited more storage of moisture in the root

zone, supplemented plot or the evaporation rate was too high,

taking away the advantage of diverted runoff.

Conservation methods

It was found that they had no significant effect on the yield at

p≤0.05. The systems varied marginally in the order of Semi

circular loops (1.06t)> Basin(0.93t)> Tied contour ridges

(0.888t)> Contour ridges(0.806t).

Table 3. The effect of conservation structures on mean totalyield t/ha

Conservationstructure

Cutoff

Rainfed

Basin 1.08A 0.76 B

Semi Circular loops

1.46 A 0.67 B

Contour ridges

0.99 A 0.62 B

Tied ContourRidges

1.1 A 0.65B

14


p≤0.05 using lsd.

Cow Pea

There was no significant yield difference in cowpeas under rain

fed and supplemented systems at p≤0.05. It could be due to the

factors of infiltration and evaporation as earlier mentioned.

Table 4 Effect of source of water to cow pea yield t/ha

Means with the same letter are not

significantly different at p≤0.05 using lsd.

Water conservation structures were found to have a significant

effect of yield in cowpea production. This could be attributed to

the rooting system and drought tolerance. The height of the crop

could also have been reason for significant performance because

of the lower total biomass at maturity.

Table 5 Effect of conservationstructures on cow pea mean yield t/ha

15

Source of water

Yield t/Ha

Cut off Drain

0.344A

Rain fed 0.277A

Conservation structure

Meant/Ha

Basin 0.456A

Semi Circular loops

0.389B

Contour ridges

0.215C

Tied Contour ridges

0.178C


p≤0.05 using lsd.

Maize

In maize, it was found that the supplemental system from a cut

off and the rainfed type had a significant effect on the maize

yield at p≤0.05. The reason could be the rooting system of maize.

Table 6 Effect of source of water to Maize yield t/ha



Individual conservation structures had significant effects on the

yield of maize where the basin system was outstanding, yielding

1.26t/ha compared to contour ridges with 0.72t/ha.

16

Source of water

Yield t/Ha

Cut off Drain

1.186A

Rain fed 0.717B

Table 7 Effect of conservation structures on Maize mean yieldt/ha


significantly different at p≤0.05

using lsd.

Pigeon Pea

It was found that supplemental system and the rain fed only had a

significant effect on the yield at p≤0.05. The reason could be

the rooting system of and the duration of flowering which is

normally longer than annual crops. The crop showed high

adaptability to the harsh conditions.

Table 8 Effect of source of water to Pigeon pea yield t/ha

17


Meant/Ha

Basin 1.256A

Semi Circular loops

0.967B

Contour ridges

0.867BC

Tied Contour ridges

0.717C

Source of water

Yield t/Ha

Cut off Drain

1.863A

Rain fed 0.950B


p≤0.05 using lsd.

Individual conservation structures had no significant effects on

the yield of pigeon pea where in the semi-circular loops system

the yield was 1.783t/ha compared to contour ridges with 1.1t/ha.

Specific conservation structures that were used to test the crop

did not have a significant effect on the yield of pigeon pea. The

exceptional performance by the pea can be attributed to the

physiological set up of the crop.

Table 9 Effect of conservation structures on Pigeon Pea meanyield t/ha

18


Meant/Ha

Basin 1.783A

Semi Circular loops

1.650A

Contour ridges

1.133A

Tied Contour ridges

1.100A


p≤0.05 using lsd.

Sorghum

In sorghum, it was found that the supplemental system from a cut

off and the rain fed type had a significant effect on yield at

p≤0.05. The crop responded to supplemental water that increased

the yield by about 50% as compared to the rain fed crop.

Table 10 Effect of source of water to Pigeon pea yield t/ha



There was significant effects on the yield of sorghum among

conservation structures where in the contour ridges the yield was

1.683t/ha compared to the basin system with 0.767t/ha. This crop

seems to be susceptible to water logging since all three systems

have a tendency to pond other than contour ridges. There was no

significant difference in yield of sorghum in the three water

ponding systems.

19

Source of water

Yield t/Ha

Cut off Drain

1.425A

Rain fed 0.809B

Table 11 Effect of conservation structures on Sorghum mean yield

t/ha


significantly different at p≤0.05

using lsd.

Wheat

Wheat generally a temperate crop performs well at high altitudes.

Marigat is at below 1500m amsl. This may have been the reason why

the rain fed and supplemental systems did not have a significant

difference in yield at p≤0.05.

Table 12 Effect of source of water to Wheat yield t/ha

20


Meant/Ha

Contour ridges

1.683A

Semi Circular loops

1.066B

Tied Contour ridges

0.950B

Basin 0.767B

Source of water

Yield t/Ha

Cut off Drain

1.033A

Rain fed 0.566A


p≤0.05 using lsd.

Soil and water conservation structures had a significant effect

on the yield in wheat at p≤0.05. Semi-circular loops had a yield

of 1.206t/ha as compared to that of contour ridges of

0.323t/ha.

Conclusion

These experiences of water harvesting (rainfall, river, borehole,

traditional wells etc) for agricultural production combined with

the appropriate selection of a high yielding crop and

conservation method in the studied area is a technique for

mitigating climate change impacts in Africa as most of the

population are farmers and pastoralists, who solely depend on

arable land rain water, and pastures for subsistence livelihood.

21

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