Role of Molybdenum on Yield, Quality, and Photosynthetic Efficiency of White Clover as a Result of the Interaction with Liming and Different Phosphorus Rates in Andisols

A greenhouse study was conducted to determine the effects of liming, molybdenum (Mo), and phosphorus (P) rates on yield, mineral and nutritional quality, and photosynthetic efficiency of Trifolium repens L. in two Andisols. The experiment used a factorial design with four, three, and two rates for Mo, P, and lime. Molybdenum and P application increased both shoot dry weight and Mo shoot concentration (10–30%). A strong competition for sorption sites between phosphate and molybdate resulted in an increase of available Mo in soil solution and therefore an increase of Mo uptake (20–40%). Significant increases (P ≤ 0.05) were observed in plants' mineral and nutritive quality and photochemical efficiency. This effect was greater in limed soils. Our results suggest a SPAD 50 value can be used as indicator of an adequate N shoot concentration in T. repens, and Mo fertilization is required to improve pasture yield and quality for livestock production.