The use of biostimulants, which either
feed indigenous microbial populations or add microorganisms
to existing soils, is starting to gain popularity. Increasing the activity of
benign soil microbes-especially in relatively sterile sand-constructed rootzones is of great importance because they may help to
increase plant nutrient uptake and stress tolerance. The objectives of this research were to study
the effect of applying a seaweed extract and a microbial inoculant
on turfgrass growth, and nutrition. In a glasshouse experiment, rose pots measuring 15cm x 18cm (3L)
were filled with a rootzone mixture to USGA
specifications. The pots were divided into ten separate treatments. Five treatments received two-thirds and five
treatments received one-third of a recommended nutrient package. Separate
treatments of bentonite clay carrier at the
recommended rate of 12.5 gm.m-2, seaweed extract at the
recommended rate of 50 gm.m-2 and microbial inoculant
(bacteria and fungi) at the recommended rate of 25 gm.m-2 were
applied to both nutrient rates. An additional treatment containing a mixture of
the seaweed extract and microbial inoculant at their
respective recommended rates was applied to each nutrient rate. Control
treatments were used which only received two-thirds and one-third nutrient
rates. Grass weights, tissue N, P, K, Fe, and Mg concentrations and rootzone N, P, and K concentrations were measured on a monthly
basis for three months. Grass colour was measured at the end of the experiment.
The application of the seaweed extract/microbial inoculant,
and the microbial inoculant treatments increased
grass growth. Tissue N concentrations were significantly increased by the seaweed
extract treatment on two measurement dates. Tissue K was increased on two
measurement dates by the microbial inoculant
treatment. The seaweed extract/microbial inoculant
treatment significantly increased grass colour compared to the control.