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 prolonged droughts an increase in time to wilting by a few days may diminish yield losses. Soil incorporation of highly water-swelling polymers (hydrogels) to increase time to wilting and to increase biomass production was investigated. The soil conditioner used was a post cross-linked sulphonated polystyrene. The soil used was a sand with sunflowers (Helianthus annuus) grown for 10 wk. The plant parameters examined were emergence time, growth, wilting time and aboveground biomass. Soil parameters included field capacity, wilting 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 conditions. Second-order factorial designs were applied and the resultant mathematical models proved adequate and reasonable. The presence of soil conditioner resulted in improvements of all parameters investigated. Key words: Arid soils, water economy, soil conditioners, experimental design