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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Perennial Crops Laboratory » Research » Publications at this Location » Publication #337121
Title: Ambient and elevated carbon dioxide on growth, physiological and nutrient uptake parameters of perennial leguminous cover crops under low light intensities

Author
item Baligar, Virupax
item Elson, Marshall
item HE, Z - University Of Florida
item LI, Y - University Of Florida
item PAIVA, A - University Of Santa Cruz - Brazil
item AHNERT, D - University Of Santa Cruz - Brazil
item FAGERIA, N - Embrapa

Submitted to: International Journal of Plant and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2017
Publication Date: 4/21/2017
Citation: Baligar, V.C., Elson, M.K., He, Z.L., Li, Y.C., Paiva, A.D., Ahnert, D., Fageria, N.K. 2017. Ambient and elevated carbon dioxide on growth, physiological and nutrient uptake parameters of perennial leguminous cover crops under low light intensities. International Journal of Plant and Soil Science. 15:1-16.

Interpretive Summary: In the tropics, soil degradation is a major cause of poor plantation crop establishment and low productivity. Inclusions of quick growing legume cover crops during the early establishment of tropical plantation crops reduce soil degradation due to erosion and nutrient leaching. Adaptability and optimum growth of cover crops in plantation crops is affected by the inherent nature of the cover crop species and the light intensity at canopy levels. Globally concentrations of atmospheric CO2 are increasing and have an implication on crop growth. A better understanding of required light intensity in these changing carbon dioxide levels will help in increasing the success of cover crops utilization in plantation crops. In this paper we report the growth parameters and essential nutrient uptake parameters of five important perennial tropical legume cover crops (Calopo/frisolla, Jack bean, Brazilian lucerne, Leucena, and Mucuna) were significantly influenced by light intensity and levels of carbon dioxide. Brazilian Lucerne and Jack bean were more efficient in nutrient use efficiency of N, K, Mg, Cu, Fe, and Mn, while Calopo and Leuacena were more efficient in Zn use efficiency and Leuacena was efficient in P use efficiency. This information will be of use by farmers in the tropics to select the appropriate type of cover crops to reduce soil degradation and improve soil fertility and crop yields.

Technical Abstract: Adaptability and optimum growth of cover crops in plantation crops is affected by the inherent nature of the cover crop species and the light intensity at canopy levels. Globally concentrations of atmospheric CO2 are increasing and this creates higher photosynthesis and nutrient demand by crops as long as the light intensity is adequate. An experiment was undertaken to assess effects of ambient (400µ mol mol-1) and elevated (700µ mol mol-1) levels of [CO2] on the growth and physiological parameters and nutrient use efficiency in five selected tropical perennial legume cover crops (Calopo/frisolla, Jack bean, Brazilian lucerne, Leucena, and Mucuna) under low levels of photosynthetic photon flux density (PPFD; 100, 250, and 450 µmol m-2 s-1). Overall, total dry biomass, root dry biomass, root/shoot ratio, and stem height were significantly influenced by levels of [CO2] and PPFD and cover crop species. With some exceptions, these growth parameters showed significant interactions between cover crop species x [CO2] and cover crop species x PPFD. In all the cover crops evaluated, increasing levels of [CO2] and PPFD increased RGR, NAR, WUE and SPAD, and decreased water flux (VO). With few exceptions, overall macro-micronutrient concentrations were significantly influenced by levels of [CO2], PPFD and species. Macro-micronutrient uptake levels were significantly influenced by cover crop species; however with few exceptions, levels of PPFD also had significant effects on the uptake of all nutrients. Across crop species, increasing [CO2] and PPFD increased uptake of all nutrients and this was a reflection of higher shoot dry matter accumulations at the higher levels of [CO2] and PPFD. Nutrient influx (IN) of all the nutrients were significantly influenced by crop species. However, with few exceptions levels of [CO2] and PPFD and their interactions had no effects on IN of nutrients. Cover crop species and levels of [CO2] and PPFD and the interaction of PPFD x species had significant effects on nutrient transport (TR). Macro-micro nutrient use efficiency was significantly influenced by levels of [CO2], PPFD and crop species. Brazilian lucerne and Jack bean were more efficient in nutrient use efficiency of N, K, Mg, Cu, Fe, and Mn; while Calopo and Leuacena were efficient in Zn use efficiency and Leucaena was more efficient in P use efficiency.