EVALUATION OF IN SITU RAINWATER HARVESTING TECHNIQUES FOR CROP PRODUCTION AND SOIL CONSERVATION IN THE SEMI-ARID AREAS OF EASTERN ETHIOPIA

Transcription

1 EVALUATION OF IN SITU RAINWATER HARVESTING TECHNIQUES FOR CROP PRODUCTION AND SOIL CONSERVATION IN THE SEMI-ARID AREAS OF EASTERN ETHIOPIA By: Kibebew Kibret (Dr.) Dr. Kindie Tesfaye and Dr. Bobe Bedadi Haramaya University Financial support: African Water Facility through MoWR of Ethiopia Presented at the 4 th AFRHINET International Networking, Dissemination and Round Table Event 23 February 2013; Ras Amba Hotel, Addis Ababa

2 1. Introduction

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4 Siltation problems Ex-situ Efforts

5 Key issues o Can in situ rainwater harvesting provide affordable alternative? o From the myriad number of varieties, which ones fit best to the climate, soil types, crops, and socio-economic/sociocultural conditions of a specific location? Finding a plausible answer to such questions requires evaluation of the practices under the specific conditions of a given geographic environment.

6 A research was conducted at selected sites known for their moisture deficit stress: To evaluate different rainwater harvesting techniques for production of different crops grown under different soil types and climatic conditions The study areas: Jigjiga (9o 20 N and 42o 47 E; 1750 m.a.s.l; mm RF ) Babile (9 13 N and E; 1644 to 1655 m.a.s.l; 719 mm RF ) Dire Dawa (9o 36 N and 41o 51 E; m.a.s.l; 604 mm RF) Meisso (9º 23 N and 40º 77 E; 1400 m.a.s.l.; )

7 Location of the study areas Study sites

8 Cropping seasons: Jigjiga: 2008 Babile: 2008 & 2009 Dire Dawa: 2008 and 2010 Meisso: 2008 and 2009 Crop varieties used: Test crop Varieties Adaptation area Altitude (m.a.s.l) Rainfall mm) Days to maturi ty Year release Sorghum 76TI#23 Less than Common Awash Melka-98 bean (PAN-182) All over the /99 country Maize Katumani of

9 The five in situ water harvesting techniques evaluated were: in-field rainwater harvesting with a runoff strip width of 1 m (IRWH1), in-field rainwater harvesting with a runoff strip width of 1.5 m (IRWH1.5), in-field rainwater harvesting with a runoff strip width of 2 m (IRWH2), tied-ridge (TR), and conventional tillage (CT)-flat

10 Siltation problems

11 Infield Rainwater Harvesting (IRWH) Basin Tied-ridges (TR) Conventional (flat bed) tillage

12 Design used: randomized complete block design (RCBD) with three replications Parameters measured: Soil (routine analysis including soil water retention curve, and seasonal soil moisture measurementgravimetric) Crop (yield and yield components) Climate (mainly precipitation and temperature)

13 Results Table 1. Selected physico-chemical properties of soils of the experimental sites Jijiga Particle size distribution (%) b (g ph OC N P Exchangeable bases (cmol c /kg) CEC i AWC San Silt Clay cm -3 ) (%) (%) (ppm) Ca Mg K Na cmol c /kg) (cm/hr ) (%v/v) Babile Dire Dawa Meisso

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15 Seed yield (kgha -1 ) Maize grain yield (kgha -1 ) Grain yield of sorghum (kgha -1 ) CT TR IRWH1 IRWH1.5 IRWH2 In-situ water harvesting practices 0 CT TR IRWH1 IRWH1.5 IRWH2 In-situ water harvesting practices CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices

16 Grain yield of sorghum (kgha -1 ) Grain yield of maize (kgha -1 ) CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices

17 Seed yield of common bean (kgha -1 ) Grain yield of Maize (kgha -1 ) Grain yield of Sorghum (kgha -1 ) CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices 0 CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices

18 Seed yield of common bean (kgha -1 ) Grain yield of Maize (kgha -1 ) Grain yield of Sorghum (kgha -1 ) CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices 0 CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices CT TR IRWH1 IRWH1.5 IRWH2 In-situ rainwater harvesting practices

19 Conventional tillage IRWH TR

20 Changes in soil moisture storage as affected by different in situ rainwater harvesting treatments under common bean field during the 2010 cropping season at Dire Dawa.

21 CONCLUSION AND RECOMMENDATION In almost all the experimental sites and test crops, the in situ rainwater harvesting practices tested performed better than the conventional (flat seedbed) tillage practice in terms of soil moisture storage in the rhizosphere and aboveground biomass and grain yield of the test crops. The performance of the in situ rainwater harvesting practices, particularly the in-field ones, was much better in medium to fine textured soils as compared to the coarse-textured soils.

22 CONCLUSION AND RECOMMENDATION From the in situ rainwater harvesting practices tested, the in-field rainwater harvesting practices with different runoff strip widths outperformed the tied-ridge in almost all the parameters considered for evaluation. The runoff strip widths of the IRWH did not result in considerable differences in most of the parameters considered and thus imply that IRWH with 1 m wide runoff strip can give equivalent benefit to those of 1.5 and 2 m wide runoff strips. Although all the tested crops performed well under the IRWH practices, maize and sorghum seem to be best suited for these practices. The IRWH practices are best for Jijiga, Dire Dawa, and Meisso sites as compared to Babile.