Assessment of Phosphorus Supply Rate to Common Vetch by using Ion Exchange Membranes
Noulas, C., D. Vlachostergios and C. Tsadilas . 2012. Communications in Soil Science and Plant Analysis 44:275-286
Abstract
In the present study we examined the suitability of resin membranes (PRS ™) to estimate phosphorus (P) supply rate. For this purpose common vetch (Vicia sativa L.) was gown in a pot experiment with no (P0= 0 kg P /ha) and with P fertilization (P1= 87 kg P /ha) and P supply rate was assessed using a specially pre-treated anion exchange membrane encased in a plastic applicator buried in the soil for two-week intervals. Cumulative P supply rate was also calculated at the end of the growing season. Soil moisture content was kept at field capacity while soil temperature was recorded daily throughout the growing season. Results showed that resin membranes assessed considerably higher soil P supply rate in the treatments including P fertilization compared to control either in pots planted with common vetch or in bare soil. Without roots competition (non planted pots) soil P supply rate ranged on average from 3.89 μg ion/10 cm2/2 week (P0) to 59.28 μg ion/10 cm2/2 week (P1). When root completion was considered (pots planted with common vetch) P supply rate varied on average from 2.70 μg ion/10 cm2/2 week (P0) to 44.91 μg ion/10 cm2/2 week (P1). Under the same P treatment, soil ion movement processes (i.e. ion diffusion) that can be modified by the presence of root hairs, may explain the small differences in absolute values between planted and non-planted pots. Cumulative value of P supply rate was significantly lower in the treatment with common vetch plants and fertilizer addition than under bare soil and the same amount of fertilizer. Yield related parameters and P concentration in aboveground plant parts were comparable to those referred in the literature. P supply rate was more closely related to P uptake by plants (r2=0.96), which is considered a strong evidence that this method of availability estimation is effective and may be used for this purpose. PRS ™ probes under controlled soil conditions with respect to temperature and moisture may estimate P supply rates to common vetch plants successfully. They seem to be capable to differentiate P supply in fertilized soils and give results significantly
correlated to yield parameters of this crop. However, it is not recommended to use it for making fertilizer recommendations before they be tested under natural conditions especially in dry
environments.
Key Words
Vicia sativa L, anion exchange membranes, soil-plant phosphorus, yielding parameters
