Effects of a polymeric soil conditioner on the early growth of sunflowers

In sandy soils water shortage may result in the loss of crops. During prolo nged droughts an increase in time to wilting by a few days may diminish yie ld losses. Soil incorporation of highly water-swelling polymers (hydrogels) to increase time to wilting and to increase biomass production was investi gated. The soil conditioner used was a post cross-linked sulphonated polyst yrene. The soil used was a sand with sunflowers (Helianthus annuus) grown f or 10 wk. The plant parameters examined were emergence time, growth, wiltin g time and aboveground biomass. Soil parameters included field capacity, wi lting point and available water. These parameters were correlated with the polymer content in the soil and the degree of water equilibrium swelling of the polymers. The tests were performed in pots under water deficiency cond itions. Second-order factorial designs were applied and the resultant mathe matical models proved adequate and reasonable. The presence of soil conditi oner resulted in improvements of all parameters investigated.