Browsing by Subject "phosphorus uptake"

Nutrients get deposited in lake sediment from agricultural areas and other anthropogenic activities resulting in internal P loading and eutrophication. On the other hand, the situation with P rock (non renewable resource) used for production of mineral fertilizer is alarming that result in the depletion of P rock and increase P fertilizers price. The issue can be minimized by sediment removal and recycling nutrients from sediment for crop production. The existing results on sediment P availability for crops showed contradictory results and suggested that sediment P bioavailability for the crop is influenced by sediment iron to phosphorus mass ratio. However, comprehensive studies confirming their relationship are currently lacking. Hence, the study aims to determine the potential of sediment as fertilizers for crop (ryegrass) from several eutrophic lakes (in Finland and Estonia). The aim is to identify the effect of different lake sediments on ryegrass aboveground biomass and nutrient uptake. The study was conducted on greenhouse for around 6 months. Randomised complete block design was used for the experiment. The experimental treatments include sand with six different lake sediments: Peipsi, Lämmijärv, Kutajärvi, Kymijärvi, Matjärvi and Enonselkä basin of Vesijärvi, mineral fertilizer (positive) and without P fertilizer (negative) control. The biomass (yield) and nutrient uptake by the plants were measured and then analyzed for nutrient content. Significant effect of lake sediment was observed on ryegrass yield and P uptake. The significantly higher yield was observed for Lake Peipsi sediment treatment than in both controls. The ryegrass dry matter yield was greater in sediment treatments than negative control. Also, ryegrass yield was found to be greater in some sediment treatments than positive control. The concentration of nutrients (sulphur, calcium, magnesium, and potassium) was sufficient in ryegrass plant in all lake sediment treatments. The P uptake from Enonselkä sediment treatment was the highest whereas from Kutajärvi sediment treatment was the lowest. The P uptake was the highest (16.3 kg ha-1) in Enonselkä sediment treatment with the lowest Fe:P ratio of 12. Moreover, the result suggests that Fe:P mass ratio is one of the factors/sediment properties that determine P availability to the crops. However, other sediment properties may also affect P availability in the plants as organic P fraction was also used as an additional P source in some cases. The sediment increased C content and organic matter content compared to controls which improved ryegrass growth in sediment treatments. The increase in nutrient uptake and biomass in lake sediment treatments showed that lake sediment can be potential alternatives for fertilizers in nutrient deficient soil.