Phosphorus Fertilizing Effects of Biomass Ashes

Abstract

The reutilization of biomass ashes in agriculture is important to create nutrient cycles. In field and pot experiments we investigated the fertilizing effects of different biomass ashes (rape meal ash, straw ash, and cereal ash) for eight different crops on a loamy sand and a sandy loam. Special emphasis was given to phosphorus (P). The ashes showed large differences in their elemental composition. The highest P contents (10.5%) were measured in the cereal ash, and lowest in straw ash (1% P). The solubility of P in water was low; however, about 80% of P was soluble in citric acid. Generally, the P fertilizing effect of ashes was comparable to that of highly soluble P fertilizers such as triple superphosphate. The ash supply resulted in an increase of P uptake of cultivated crops as well as in increased soil P pools (total P, water-soluble P, double-lactate-soluble P, oxalate-soluble P) and P saturation. The ash effects depended also on the cultivated crop. Good results were found in combination with phacelia, buckwheat, and maize. Provided that biomass ashes are low in heavy metals and other toxic substances, the ashes can be applied in agriculture as a valuable fertilizer.

Effect of bioeffectors and recycled P-fertiliser products on the growth of spring wheat

“…These problems aside, from the results presented here, it would not appear that wood ash and straw ash have great potential as P fertilisers, since the relative increase in biomass yield was not above 25 % in comparison to the HK Kalke and UCPH experiments showing yield increases of 50 % or more, even for sewage sludge ash. This result contradicted an earlier study in which a high P-fertilisation effect was found for rape meal, straw and cereal ashes [63]. However, as observed from the PCA plot, a small effect was observed on the plant elemental composition due to the wood ash and DKP treatments and greater effect of the straw ash treatment, but these differences were not clearly associated with differences in the aboveground biomass.…”

Combined waste resources as compound fertiliser to spring cereals

“…However, the results of the present study suggest that the method is not suitable for predicting the amount of plant-available P in waste materials. Schiemenz et al (2011) recommend extracting biomass ash with citric acid, which dissolves around 80% of ash-P, for prediction of the P fertilisation effect.…”

Harmonising conflicts between science, regulation, perception and environmental impact: The case of soil conditioners from bioenergy

“…This was attributed to the low availability of P within ash as identified by Khanna et al (1994). Through dissolution tests with different ash/ water ratios, Khanna et al (1994) observed the rapid dissolution of K, Ca and Mg, and the comparative insolubility of P. In addition, an increased soil pH following the addition of ash may have further reduced the solubility and availability of P in soil (Demetz and Insam, 1999;Schiemenz et al, 2011), and precipitation of phosphate ions with Fe and Al can form insoluble compounds, lowering the H 2 PO 4 content taken up by plants (Omil et al, 2011). The increase in pH of the digestate following mixing with ash may also result in the gaseous loss of ammonia (Bougnom et al, 2012).…”

“…Ash provides a source of micronutrients (Demeyer et al, 2001;Kuba et al, 2008;Odlare and Pell, 2009;Schiemenz et al, 2011). Primary production Gross primary productivity (GPP) measures the rate of solar energy conversion into biomass.…”