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Over reliance rain-fed agriculture is a contributor to food shortage and insecurity

A PROPOSAL TO STUDY DIFFERENT SOIL ORGANIC AND INORGANIC AMENDMENT OPTIONS FOR THE MANAGEMENT OF SALINE/SODIC SOILS AND TEST HIGH VALUE CROP SUITABILITY FOR KALACHA IRRIGATION SCHEME Obanyi S.N., Muya E. Dub G. and Radiro M. INTRODUCTION.

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Over reliance rain-fed agriculture is a contributor to food shortage and insecurity

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  1. A PROPOSAL TO STUDY DIFFERENT SOIL ORGANIC AND INORGANIC AMENDMENT OPTIONS FOR THE MANAGEMENT OF SALINE/SODIC SOILS AND TEST HIGH VALUE CROP SUITABILITY FOR KALACHA IRRIGATION SCHEME Obanyi S.N., Muya E. Dub G. and Radiro M.

  2. INTRODUCTION • Over reliance rain-fed agriculture is a contributor to food shortage and insecurity • Frequent and prolonged droughts, farmers are turning to irrigation as a way of increasing agricultural production in ASALS • High population growth rate of 3% has resulted in increased land pressure and migration of farmers to the ASAL = need for increased food production • Change of land use from pastoralism to irrigated farming without adequate capacity to face the challenges of sustainable irrigation production

  3. Statement of the problem • The Kalacha irrigation scheme – reduced crop productivity by 80% between 1984 and 2005 • Largely attributed to increased sodium, poor soil structure and loss of plant nutrients • Abandoning crop production for pasture and trees • A similar scenario is repeated in many other irrigation schemes in the ASAL

  4. Crop production decline and this can be reversed if the soil problems are addressed There is imbalance of cations such as Ca, Mg and K leading to artificial deficiency Low organic matter as farmers do not apply any manure and the stover is fed to livestock About 40% or about 25 million ha of the land of Kenya is covered by soils that have salinity and/or sodicity problem(s) with saline, saline-sodic and sodic soils, covering 2.9, 14.0 and 8.2 million ha respectively (Wamicha et al., 1986; Muchangi, 2005; Ngigi, 2002; Muchena, 1987) Of the area under irrigation, more than 50% is undergoing severe land degradation through secondary salinisation and sodification mainly due to improper irrigation and soil fertility management practices (Muchangi, 2005; Ngigi, 2002) Statement of the problem cont…

  5. Statement of the problem cont… • High sodium leads to soil dispersion, collapse of soil structure, blockage of soil pores, low water infiltration, water logging, poor aeration resulting in poor crop growth and can lead to complete crop failure (Landon, 1991) Degraded systems: A case for Hareri scheme, Mandera

  6. Justification of the study • Vision 2030 emphasizes improving agricultural sector, the driving force of Kenyan economy. Expansion of irrigation at a rate of 4,000ha per year to have 1million acres under irrigation • Spices are low volume high value crops that can be produced as cash crops and can contribute to reducing the high poverty levels (65%) • Spices can be value added and have a long shelf life, they are also less susceptible to wildlife damage • Increase farmer income thus help alleviate poverty one of the MDGs

  7. Justification of study cont.. • The area has a high potential for spices production and there exists a big market potential as all spices used in the area are imported • The imported spices for manufacturing are also produced in areas with almost similar biophysical characteristics as the study site • Kenya’s onion production has stagnated at about 11t/ha (FAO, Statistics 2002) top producing countries such as South Korea produce up to 46 t/ha and Tanzania is about 35t/ha. • Kenya has potential to produce over 20 t/ha under irrigation.

  8. OBJECTIVES OF STUDY The study will have three main objectives: • To test different soil management options for the improvement of saline-sodic soils. This will include 6 soil amendments i.e. gypsum, vermicompost, compost manure, fortified farm yard manure and crop based options (grasses and legumes) as green manure • To develop sustainable and economically viable production systems through testing high value crops suitability for Kalacha. • To disseminate results to the community and other development agencies so that they can make informed decisions on saline/sodic soils management in other irrigation schemes

  9. Kalacha irrigation scheme in Marsabit District lies between Longitude 2° 30’ N and Latitude 37° 30’ E. 300 meters above sea level, temperatures of approximately 300C Bi-modal rainfall averaging 225mm per year Wind speed is over 4m/s Evaporation is about 2280mm/year surrounded by Maikona, Asie and Kargi hills and drains to Chalbi desert METHODOLOGYThe study area location Kalacha Irrigation Scheme

  10. Soils Table 1. Soil physical properties • Developed on lacustrine plain and limestone sediments • Broadly classified into four soil units with variations in depth, aggregate stability, infiltration rates and soil moisture holding capacity • Generally they have low aggregate stability of <50% at 10% within the top 10cm (Table 1) • Water holding capacity is low in the sub-soil possibly due to development of a hard pan

  11. Table 2. Soil chemical properties

  12. Soil chemical properties • The pH increases down the profile above 8.2 that is used to classify sodic soils (FAO, 1988) • Chemical properties show low carbon and nitrogen (Table 2) • Phosphorus levels decrease down the profile, Calcium and Magnesium levels are high compared to the critical levels • Electrical conductivity (ECe) increases with depth being highest at 40-60cm but below 4 ds/cm • ESP % is high down the profile, soil is sodic

  13. Methodology cont…. • The study will therefore have 3 main strategies in achieving this: • Plant-based approach, a deep rooted legume to address the soil hard-pan and a shallow rooted grass • Organic manure, vermicompost and compost will address low organic matter, soil aggregate stability, water holding capacity, available nutrients • Water use efficiency and leaching of sodium salts • Drip and furrow irrigation will be used

  14. Parameters to be measured • Crop yields under the different management options and identifying the best options • Quantifying the hydraulic conditions of the soil to provide data for calculating the irrigation water application rate and time setting. • Evaluating the different spices for adaptability to the climatic and soil conditions

  15. Soil moisture measurement • neutron probe, moisture read at 4 depths = access installed to 60 cm • Monitoring the soil water status on a regular basis can identify soil structural problems, causing low crop water use and consequently a poor yield • Neutron probe will be calibrated for the soil type • Measurements will be at 4 depths on selected plots where soil analysis will be done

  16. manure and compost making • Manure/compost will be made using plant materials, ash and animal manure as described in IIRR, 2002 • When the manure is ready it will be sampled and analysed to know its nutritional value. • Vermicompost will be made using locally sourced earthworms • Methods of analysis are described in Okalebo et al., 2002.

  17. Experimental Design and Treatments Experiment 1 • 2 irrigation methods (furrow or drip) • Cover crop type – shallow and deep rooted • Soil amendments – gypsum, vermicompost, compost manure, farm yard manure and crop based options (grasses and legumes) as green manure • There will be 3 replications (blocks) = 12 plots • Split plot design with irrigation methods as main plot grass and legume treatments being main sub-plots and amendments being sub-sub plots • Test crop - onion

  18. Experiment 2 The performance of 4 levels of vermin-compost • The parameters that will be studies will be: • The effects of vermicompost on soil aggregate formation and stabilization. • The effects of vermicompost on salinity and sodicity levels. • The hydraulic conductivity of the different soils under the different vermicompost levels • 4 replications, RCBD

  19. Experimental layout Block 1 Block 2 Block 3 Block 4

  20. Experiment 3 • 5 spices will be tested under the current soil conditions • The spices include Garlic, onion, ginger, Chilli and Tumeric • The 5 spices will be replicated three times • RCBD

  21. Statistical Data Analysis • Treatment effects on sodium and salt control and onion yield will be examined by ANOVA using the general linear model • Statistical Analysis System (SAS) version 8.1 of the SAS institute Inc. Cary, NC, USA • Treatments found to be significantly different will be separated by Least Significance Differences (LSD) (Steel and Torrie, 1960) • All tests will be performed at the 0.05 significance level.

  22. Expected Outputs • Salinity and sodicity at Kalacha through use of different crop types, organic and inorganic soil amendments controlled. • Higher spice yields and hence higher incomes for the farmer realized • Better management of saline-sodic soils through improved technologies and knowledge attained. • Farmers capacity built to produce and market spices Estimated budget: 1.418m

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