Effect of organic/inorganic compound fertilizer on the yield of crop and fodder double-cropping system in the Tibetan Plateau

Double-cropping system in the Tibetan Plateau refers to harvesting fodder after main grain harvests in the year. This not only provides fodder for livestock in winter and spring, but also enhances farmers’ income. It serves as an important overall driver of socio-economic development in the Tibetan Plateau region. In this study the effects of organic/inorganic compound fertilizer on the yield of double-cropping systems in the Tibetan Plateau were analyzed in a controlled field experiment using winter naked barley, fodder vetch or fodder maize. Results showed that organic/inorganic compound fertilizer increased soil temperature by 0.5~0.8 oC during over-wintering and reviving periods in winter naked barley. Compared with inorganic fertilizer, organic/inorganic compound fertilizer shortened the growth period of winter naked barley by 3~4 days. This served a beneficial effect for fodder vetch or fodder maize yield in the region. Leguminous plants were more adapted to the double-cropping system according to the fresh grass yield. Organic/inorganic compound fertilizer enhanced root biomass production in winter naked barley in the 10~20 cm soil depth. This also facilitated soil nutrient absorption, which in turn increased yield of winter naked barley. Furthermore, organic/inorganic compound fertilizer preserved much more soil nutrient. This significantly enhanced the growth and cultivation conditions in the farmlands of the Tibetan Plateau.