Soil fertility management for improved wheat production in UgandaChemayek B, Wasukira A, Wobibi S, and Wagoire W.W

Introduction: In Uganda, wheat is produced by smallholder farmers on the slopes of Mt. Elgon (East) and the south-westhighlands at altitudes between 1800 -2400masl. These areas have steep slopes that are prone to erosion, contributing to a loss infertility and occasional landslides. Wheat production in these areas is curtailed by low soil fertility due to intensive cropping, anduse of poor quality seed of old varieties. Farmers achieve yields of 0.5t/ha but there are potential yields of 2.5t/ha. In Kapchorwaand Kween, less than 30% of farmers use fertilizer for wheat production, and this decreases to less than 5% in the south-westhighlands. This study carried out soil fertility studies in eastern Uganda from August 2010 to Aug 2012 at 4 sites, to determine themost effective fertilizer rates for wheat production.

Objectives: (i) Determine appropriate fertilizer application rates for wheat; (ii) Assess how different farmer wheat varietiesperform under different fertilizer levels; (iii) Promote use of fertilizers and improved seed at farm level

Methodology: Study was conducted in four sites of Kapchorwa, Kween, Bukwo and Bulambuli from Aug 2010 to Aug 2012 forthree seasons. Five genotypes; Fahari, Kwale, Nkugu, UW 309 and UW 400 were evaluated under four fertilizer levels (90Kg ha-1

N and 80Kg ha-1 P Kg/ha; 60Kg ha-1 N and 50Kg ha-1 P; 30Kg ha-1 N and 20Kg ha-1 P Kg/ha and no fertilizer at all as a check) in asplit plot design. The main plots were fertilizer treatments while the genotypes constituted the subplots that were of 4 rows of 5m length and inter-row spacing of 0.3 m. Data on establishment, number of tillers, disease incidence and severity, plantheight, lodging, head length and yield (Kg) was collected and analyzed using SAS.

ReferencesWilliam Wamala Wagoire (2006). Quantification of the value of improvedwheat production options in South-western Uganda. Uganda Journal ofAgricultural Sciences, 12(1): 22-28Taye Belachew & Yifru Abera (2010). Assessment of Soil Fertility Status withDepth in Wheat Growing Highlands of Southeast Ethiopia. World Journal ofAgricultural Sciences 6 (5): 525-531

Source df Mean Squares

Establish Tillers Plt Height Head length Agro Score Stem Rust Yield

Site 3 6.43*** 51.65*** 2882.56*** 54.20*** 23.31** 856*** 5.89***

Treatment (Trt) 3 5.89*** 7.19*** 2742.16*** 14.57*** 76.93*** 44.36 3.06*

Variety (Var) 7 7.89*** 0.68 364.64** 11.44*** 8.76 353.38*** 4.12***

Rep 2 0.9 1.72 725.21** 1.31 24.19* 685.12*** 2.8

Site*Trt 9 6.56*** 3.93*** 531.95*** 3.99*** 21.64*** 39.81 1.65

Site*Var 12 2.92*** 1.42* 654.87*** 10.67*** 10.32* 828.12*** 2.66**

Trt*Var 15 0.717081 1.07 105.3556 0.88 15.09*** 49.71 0.62

Site*Trt*Var 36 0.530627 0.85 68.37347 1.08 11.92*** 52.32* 0.34

Results and Discussion

Results indicated highly significant differencebetween site and all measured parameters.Considerable significant differences were alsorecorded between treatments and measuredparameters. The observed highly significantdifferences is because the soils in these sites arehighly nutrient deficient and so any soil nutrientamendments results in increased yields.

There were significant differences amonggenotypes for all parameters Fahari yieldinghigher (1.84 t/ha) and UW369 (1.62t/ha) at 90NKg/ha while Kwale (1.96t/ha) and UW400(2.0t/ha) gave higher yield at 60N Kg/ha.

0.00

0.50

1.00

1.50

2.00

2.50

Yie

ld (t

/ha)

Genotypes

Yield of five wheat genotypes at different fertilizer levels

30N

60N

90N

Nkungu the local genotype performed poorly underall treatments compared to improved genotypes. Thisreflects genotypic differences in adaptation todifferent fertilizer levels. The results indicated highresponsiveness of improved genotypes to nutrientapplications implying that theses genotypes have hada lot of good traits incorporated in them among whichis improved response to nutrient applications.

The lack of positive response to fertilizer by Nkungu was because of beingvery tall and with weak stems that led to early lodging in plots with fertilizerleading to low yields due to inadequate grain filling. Analysis of varianceindicated considerable significant interaction between site and treatmentsfor all parameters. Further more significant interactions were in site andvariety

Conclusion: Fertilizer application increased yields in improved genotypesthan the local cultivar. Genotypes responded differently to fertilizer levelswith Kwale and UW400 giving better yields at 60N Kg/ha. These resultsindicate the potential for improving wheat productivity through applicationof appropriate amounts of fertilizer and use of elite varieties, in order toimprove the livelihoods of wheat farmers.

*Value significant at P≤0.05; **Value significant at P≤0.01;***Value significant at P≤0.001