The influence of management practices used by farmers on productivity and the occurrence of field-peas pests and diseases in Kabale District, Uganda

Abstract

Field Peas (Pisum Sativum L.), a leguminous crop mainly grown in the highlands of south western Uganda, has a high economic value. It is a food security and highly liked crop in areas of production. Despite its importance, field peas productivity has remained low with yield not exceeding 800 Kg ha-1 in farmers fields compared to the potential yield of 2000 Kg ha-1 elsewhere. This can be attributed to the current limited research attention on the crop. As such, field peas production in Uganda is still based on traditional methods like rough seed beds, no weeding, unimproved varieties, broadcasting at unknown seed densities and limited control of pests and diseases. From literature, improved farming practices like thorough seed bed preparation is responsible for the observed high yields elsewhere while insect pests and diseases have been significant constraints to field peas productivity. However, the influence of the rest of the field peas farmer practices on the occurrence of field peas pests, diseases and field peas yield in Uganda is not yet known. In view of this, three studies were conducted in two sub counties of Bubare and Hamurwa of Kabale district, southwestern Uganda with a goal of investigating the influence of management practices used by farmers on productivity and the occurrence field peas pests and diseases. The first study aimed at establishing farmers’ knowledge on field peas production, pests and diseases. Results from a Participatory Rural Appraisal (PRA) with 79 field peas farmer participants indicated that despite field peas being the third and fourth dominant cash and food crop respectively, basic agronomic practices such as weeding and seedbed preparation were not being used. Farmers also identified declining soil fertility, land shortage and attack by insect pests and diseases as major constraints in field peas production. The second study, conducted in the second rains of 2005 (2005B) and first rains of 2006(2006A) was to determine the occurrence of major field peas pests and diseases in farmers fields through a validation exercise of the results of the PRA. Ten farmer fields were randomly selected on which data on plant population, pest and disease occurrence were collected at two weekly intervals beginning at three Weeks After crop Emergence (WAE). The data collected were analyzed with Analysis of Variance (ANOVA) using Genstat computer package and the means were separated using Fisher’s Least Significant Difference (LSD) of means at 5% significance level. Results indicated that during 2005B, pea aphids were the most prevalent insect pests with mean incidence of 18.2% followed by cutworms with the mean incidence of 0.6%. Diseases included Ascochyta blight, powdery mildews and Fusarium root rot with the mean incidences of 48.9%, 32.9% and 8.2% respectively. In 2006A, the most common insect pests were pea aphids and cutworms with mean incidences of 35.9% and 2.5% respectively; while diseases were powdery mildews Ascochyta blight and Fusarium root rot with incidences of 53.0 %, 47.1%, and 2.4% respectively. The third study aimed at determining the influence of agronomic practices on the occurrence of field peas pests, diseases and productivity. Ten farmer fields were used as experimental plots laid out in split plot arrangement in a Randomized Complete Block Design (RCBD). The main treatments were rough seed bed and fine seed bed, two weed management techniques constituted the subplots, that is, weeding and no weeding. Similar data and data collection technique as in study two were conducted. To determine grain yield, harvesting of grain was done 120 Days After Planting (DAP) and the dry matter of the samples was determined. Data were analyzed as in study two. It was found out that farmer practices of weed management and seedbed preparation did not significantly affect pest and disease incidence. While field peas weeding significantly and positively affected grain yield only in 2005B, seedbed preparation did not significantly affect grain yield at 5% level of significance. It was discovered that farmer agronomic practices have greater positive impact on field peas productivity than on control of pests and diseases. Research efforts should thus focus on increasing peas productivity through development of appropriate and farmer user friendly agronomic practices like weeding.