Tropical Grasslands (2001) Volume 35, 235240
Relay seeding forage species in rice systems in Bhutan
W. RODER1, P. WANGCHUK2, S. THSERING3 and T. GYELTSEN4
1RNR-Research Center Jakar,
Integrating forage legumes into existing rice production systems in the Himalayas could contribute towards sustaining soil fertility and diversifying production. Technologies need to be refined, especially species selection and establishment, before they can be recommended to farmers. From 1996–99 various studies were carried out across a range of conditions (elevation 300–2500 m) to evaluate effects of species, establishment method and planting date. The species used were: Aeschynomene americana, Astragalus sinicus, Chamaecrista rotundifolia, Crotalaria juncea, Desmodium intortum, Lablab purpureus, Melilotus officinalis, Trifolium alexandrinum, T. incarnatum, T. pratense, T. rueppellianum, Vicia villosa, Vigna parkeri, Lolium multiflorum, Avena sativa and Secale cereale. Broadcast-seeding was tested at 40 days before, 20 days before and after rice harvest. Water management during the rice crop and available moisture after rice harvest are the main factors influencing the feasibility of relay seeding and the potential for fodder production. Except for systems where fields were drained immediately before rice harvest, establishment by relay seeding was possible for all species tested. The most promising legumes were Chamaecrista rotundifolia for elevations below 1000 m and Vicia villosa for higher elevations. Earlier planting dates resulted in higher dry matter yields but had no consistent effect on establishment success.