Land suitability, agronomic performance and adoption of pigeonpea (Cajanus cajan [L.] Millsp.) cultivation in Uganda

Abstract

Pigeonpea has been grown in Uganda for a very long time but it is not widely cultivated across the country. It is not known whether the non-pigeonpea growing areas are not suitable, or there are no suitable pigeonpea varieties that can grow in the areas or there are social, demographic, economic, institutional and crop-specific factors that limit the farmers from adopting the crop. The objectives of the study were to (i) determine crop-land suitability for pigeonpea cultivation, (ii) evaluate diverse pigeonpea genotypes for their adaptability to different locations in Uganda and (iii) investigate non-biophysical factors that influence the pattern of pigeonpea adoption in Uganda. Geographical Information System-weighted-overlay-technique (GIS-WOT) was used to determine suitable areas for pigeonpea growing in Uganda, considering slope, temperature, rainfall and soil drainage retrieved from global databases, as key factors. The technique generated four suitability classes namely highly suitable, moderately suitable, marginally suitable and not suitable. The results of the GIS-WOT revealed that 17.4% of the area was highly suitable for pigeonpea cultivation, 39.2% (moderately suitable) while 23.3% was marginally suitable and 20.1% not suitable. The crop-land suitability classes suggest that pigeonpea is not widely cultivated across Uganda due to other reasons and not just due to non-suitability of land for the crop. Therefore, to validate the results of the crop-land suitability, the performance of diverse pigeonpea genotypes was assessed in multiple locations by setting field trials in three agroecological zones namely Lake Victoria Crescent Agroecological Zone, North Eastern Savannah Grassland Agroecological Zone, and Western Highland Agroecological Zone with field test sites at MUARIK, Ngetta ZARDI and Rwebitaba ZARDI, respectively. The results of genotype × location (G × L) analyses confirm the suitability of land for pigeonpea cultivation given that six genotypes (Gen2 (ICEAP 00554); Gen3 (ICEAP 00936), Gen4 (ICEAP 00557); Gen6 (SEPI1); Gen8 (ICEAP 90050) and Gen9 (ICEAP 00576-1) of the nine genotypes evaluated showed general adaptation across the three test locations while one genotype (Gen7-(ICEAP 00040) had a specific adaptation to Western Highland Agroecological Zone and two genotypes (Gen1-ICPL 87091 and Gen5-ICPL 86012) performed poorly in all the locations. The implication of the results of the G × L analysis confirms the general suitability of land in Uganda for pigeonpea cultivation. Therefore, other factors known to affect or influence patterns of adoption of agricultural technologies such as socio-demographic characteristics of farmers, institutional and crop specific attributes were examined to further explain the limitations to wide cultivation of pigeonpea in Uganda. To do this, a household survey was conducted in three districts with distinct AEZ and suitability classes namely Alebtong as traditional major pigeonpea growing area, Masindi as a minor traditional pigeonpea growing area, and Kabarole as a low pigeonpea production area. Data were collected from 283 farmers using a semi-structured questionnaire on factors that influence patterns of pigeonpea adoption in the study districts. The results showed that location of the farmer, age, education level, access to extension services, training, seed, market, and awareness of the benefits of pigeonpea, pests and diseases influence patterns of the crop’s adoption in Uganda. It is therefore recommended that the information from this study provide a basis for designing appropriate strategies for sustainable and increased production of pigeonpea in Uganda.