Effects of Phosphorus Addition on the Relationship between the Aboveground and Underground Biomass of Stylosanthes in Dry-hot Valley

Purpose Nutrient addition was an important measure in forage production practice, and the aim of this study was to observe the influence of phosphorus (P) addition on the changes between aboveground and underground biomass of Stylosanthes in dry-hot valley.

Method Five Stylosanthes varieties were plotted under traditional P addition and no P addition levels and the traits were measured in the dry-hot valleys (DHV).

Result (1) Traditional P addition level made P content, underground biomass, aboveground biomass and total biomass of five varieties average increased significantly (P<0.05). The root-shoot ratio decreased with soil P addition, showing that phosphorus could improve the growth ofStylosanthes in dry-hot valleys by allocation less biomass to underground. (2) The five varieties above-underground biomass mainly appeared as an isomeric growth relationship under the condition of P addition or no P addition. Compared with the other varieties, S. guianensis cv. Reyan No.7 and S. guianensis cv. Reyan No.13 easily changed under the condition of P addition or no P addition, showing a lower tolerance to phosphorus. (3) The above-underground biomass showed an isomeric growth relationship to varieties level, but an allometric growth relationship and shared a common pattern of lnU_mass=ln1.555+0.510lnB_mass, the distinguish traits of varieties played a key factors in the shift.

Conclusion This conclusion suggests that 5 Stylosanthes varieties are adaptor to the climate dry-hot valley. At the same time, results of P addition improving the Stylosanthes growth significantly show that phosphorus additions could be used as an important management measure in dry-hot valleys’ Stylosanthes production, under a variety selection of adaptation and a certain soil P addition.