Summer rainfall variability and the use of rice (Oryza sativa L.) varietal diversity for adaptation : farmers’ perceptions and responses in Nepal

Sammanfattning: Climate variability, farmers’ understanding of this and the crop varietal diversity are so far discussed inadequately in the same context. This study compared summer rainfall variability and farmers’ perceptions of rainfall changes between two periods; 2004-2008 and 1995-1999. The use of rice varietal diversity from an adaptation point of view was studied. The findings were from two rice growing agro-ecological zones of Nepal; mid-hills and western terai. The information was collected through a survey in 45 households in mid-hills and 44 households in terai, supplemented with focus group discussions and meteorological data. The analysis revealed a distinct variation in rainfall distribution with a decrease in rainfall amount in mid-hills and an increase in terai during 2004-2008. In the same period, pre and late monsoon rainfall increased in both sites. The rainfall decreased up to 41 percent in mid-hills during June-July, which has resulted in more dry spells during rice transplanting and establishment period. A concurrence of farmers’ perceptions with the rainfall data demonstrates their understanding about rainfall variability, gained by crop and weather observations. Shannon-Weiner index revealed a higher overall rice varietal diversity in terai (H′=2.58) than in mid-hills (H′=2.0). However, on average a household in each site maintained nearly the equal number of rice varieties (≈4). There was significantly higher landrace diversity in mid-hills (H′=1.5) and modern varieties diversity in terai (H′=2.17). The perceived varietal vulnerability to rainfall variability differed significantly (p<0.01). Farmers cautiously selected less vulnerable varieties whether landraces or modern for use on large areas, often considering their adaptation and production potential. The perceived production loss due to rainfall variability was negatively correlated (r=-0.29, p<0.05) with the number of varieties grown in terai, where modern varieties were dominant. Farmers’ seed selection and on-farm experimentations are seen as adaptation practices to reduce vulnerability in traditional farming systems.