The Multifactorial Effect of Digestate on the Availability of Soil Elements and Grain Yield and Its Mineral Profile—The Case of Maize

Abstract

The fertilizer value of digestate (a biogas plant byproduct) depends on its impact on the availability of soil nutrients and on the concentration of minerals, including heavy metals, in the edible crop parts. This hypothesis was verified in field experiments with maize conducted in the years 2014, 2015, and 2016 in Brody, Poland. The two-factorial experiment consisted of the digestate application method and its rate: 0.2, 0.4, and 0.8 t ha −1 . Maize yield in consecutive years fitted the quadratic regression model, reaching a maximum grain yield of 11.5, 10.8, and 9.2 t ha −1 for an optimum digestate rate of 0.56, 0.66, and 0.62 t ha −1 , respectively. The supply of N-NO 3 to maize, concomitant with a shortage of magnesium and iron, was the key factor limiting the grain yield. Cadmium concentration in maize grain exceeded its threshold content in plants fertilized with digestate. An excessive concentration of lead in grain was recorded in the dry season 2015. Cadmium concentration in grain was controlled by the availability of soil Fe and Pb by a shortage of N-NO 3 , zinc, and copper. The negative relationship of Pb with K, Na, Zn, and Fe contents in grain suggests their usefulness as agents to reduce the accumulation of heavy metals.

Effect of cleanup of spiked sludge on corn growth biosorption and leaching of metals

“…More recently, the work of Przygocka-Cyna and Grzebisz [39] showed that any increase in Fe concentration in corn grain resulted in a simultaneous decrease in Cd concentration, attesting then for an antagonism behaviour between these two elements. More clearly, Przygocka-Cyna and Grzebisz [39] stated that an increased exogenous supply of Fe results in decreased uptake by plant roots.…”

“…More recently, the work of Przygocka-Cyna and Grzebisz [39] showed that any increase in Fe concentration in corn grain resulted in a simultaneous decrease in Cd concentration, attesting then for an antagonism behaviour between these two elements. More clearly, Przygocka-Cyna and Grzebisz [39] stated that an increased exogenous supply of Fe results in decreased uptake by plant roots. And this indeed the case with our experiments, where the concentration of Fe was significantly augmented in both cleaned biosolids by 13% to 20% as this metal is added (as ferric chloride) to biosolid during the application of the leaching process [28].…”

Stability and Adaptability of Maize Hybrids for Precision Crop Production in a Long-Term Field Experiment in Hungary

“…It seems that, with the addition of chemical fertilizer to the soil, soil nitrogen increased. Consequently, the plant's uptake of this element increased, and with its transfer to the grain, the percentage of grain nitrogen increased [45]. Mulyani et al [46] reported that the combination of chemical fertilizers increased the uptake of nitrogen, phosphorus, and potassium in sugarcane.…”

Cleanup of sewage sludge spiked with Cd, Cu, and Zn: Sludge quality and distribution of metals in the “soil-plant-water” system

“…More recently, the work of Przygocka-Cyna and Grzebisz [41] showed that any increase in Fe concentration in corn grain resulted in a simultaneous decrease in Cd concentration, attesting to an antagonistic behaviour between these two elements. In fact, Przygocka-Cyna and Grzebisz [41] stated that an increased exogenous supply of Fe results in decreased uptake by plant roots.…”