Optimizing growing conditions for glasshouse studies of root and phosphorus responses of mungbean (Vigna radiata L.)

Abstract

Nutritional responses of tap-rooted legume species in glasshouse studies are often confounded by soil volume. This glasshouse pot experiment was conducted to determine root distribution and phosphorus (P) nutritional requirements of mungbean (<i>Vigna radiata</i> L.) as influenced by available soil volume in a sandy loam soil. In the experiment, mungbean was grown under increasing soil volume with pot depths up to 150 cm. Root biomass increased with soil volume. Root mass density in the upper 25 cm was highest in 50 cm deep pots, accounting for ~3, 2 and 1.2 times that of 100 and 50 cm and 25 cm pots, respectively. Shoot P content was closely associated soil volume (r² = 0.99). Phosphorus uptake in shoot per unit root mass in 50 cm pots was ~1.6 times that of 150 cm deep pots. It is recommended that mungbeans should be grown in pots at least 50 cm deep to obtain realistic growth and nutrient uptake data.