Integrated soil fertility management reduces termite damage to crops on degraded soils in western Ethiopia

Abstract

Crop damage by termite is known to be severe in degraded soils. However, the role of organic inputs in reducing crop damage by termite has not been systematically studied in Ethiopia. Therefore, the objectives of this study were to quantify (i) the influence of integrated use of manure and NP fertilizer on termite damage and pod yields of hot pepper (Capsicum frutescence L.), (ii) the optimum rate of manure and NP fertilizer for hot pepper production for the study area, and (iii) the association between different rates of nitrogen (N) fertilizer and plant damage by termite. Two separate experiments were conducted for three consecutive seasons on degraded soils that were hotspots of termite activity. The treatments in experiment 1 consisted of different rates of well-composted manure applied in combination with NP fertilizer, whereas experiment 2 consisted of different rates of N fertilizer with basal application of 44kg Pha−1. In experiment 1, the combined application of manure and NP fertilizer significantly (P<0.05) reduced plant damage but increased pod yields compared with the control treatment and the recommended NP fertilizer. Plant damage by termites decreased from 29% in the first season to 11% in the third season, while pod yield increased from 378kgha−1 in the first season to 2339kgha−1 in the third season. The results of the repeated measures data analysis also indicated significant (P<0.0001) differences among the seasons in plant damage by termite and pod yield. In experiment 2, continuous application of the different rates of N fertilizer did not significantly reduced plant damage by termite while the N effect lacked consistency on pod yield. However, the application of N at rates ≥75 and >100kgha−1 increased termite damages to hot pepper in the first and second seasons, respectively. Overall, the application of one-fourth of the recommended NP fertilizer (25/11kgN/Pha−1) along with 10t manure ha−1 was found to be optimum for hot pepper production for the study area and similar agroecosystem. Therefore, we recommend adoption of the integrated use of manure and NP fertilizer to prevent soil degradation and reduce termite damage in western Ethiopia.