Amount and speciation of N leached from a sandy soil fertilized with urea, liquid digestate, struvite and NH4-enriched chabazite zeolite-tuff

The large use and the bad management of fertilizers that are applied to soil for improving crop production have dramatically impaired soil, water, and air quality. To meet the requirements to reduce nitrogen (N) losses and all the related negative impacts on the environment and food production, it is mandatory to substitute or at least partially substitute the use of inefficient and unsustainable fertilizers with more efficient alternatives. The aim of this paper was to address the amount and speciation of the N released by a sandy soil fertilized with “slow-release fertilizers” and traditional fertilizers (urea and liquid digestate) by means of a series of column leaching experiments. The slow-release alternatives were represented by NH4-enriched zeolitic tuff and struvite, both obtained by recovering the N from liquid digestate. The treatments consisted of sandy soil fertilized with (i) urea (U) (ii) liquid digestate (LD), (iii) NH4-enriched zeolitic tuff (N-CHA) and (iv) struvite (STRV). Eight different flushing events were performed over 38 days, leachates were collected and analysed for total Kjeldahl N, organic- N, NH4 +-N, NO3 −-N, NO2 −-N and pH. U and LD lost the majority of N within the first 2 flushing events as organic N and NH4 +-N, respectively. On the other hand, STRV and N-CHA lost less N over the whole course of the experiment and with more balanced speciation. The mass balance outlined that after the experiment, native soil N was mined in U and LD treatments while in N-CHA and STRV a fraction of N from the fertilizers was still present. The results showed a slow release of N which can be used more efficiently in agricultural applications, minimizing the N losses

Effects of natural and NH4-enriched Zeolitite on nitrogen leaching from a reclaimed agricultural soil of the Ferrara province (Italy)

natural zeolites, nitrate, agricultur

Impact of sequential treatments with natural and na-exchanged chabazite zeolite-rich tuff on pig-slurry chemical composition

Notwithstanding the widespread use of natural and pre-exchanged zeolites for zootechnical effluent treatment, little attention has been dedicated to the variation in the chemical composition of the treated slurries, besides the effects on their NH4+ content. This paper aimed at elucidating the compositional variations in terms of major and trace elements of a raw pig-slurry (PS) after three sequential treatment cycles (TC) with three different grain sizes of natural and Na-exchanged zeolite-rich volcanic tuffs (natural ZTs and NaZTs). A series of laboratory batch experiments revealed that all ZTs had profoundly influenced the final PS chemical composition. As expected, the NaZTs were more efficient in terms of NH4+ removal than the natural ZTs, reaching almost 60% reduction of the initial content after three TCs. A parallel effect of this efficient removal was the remarkable increase in Na+. The Na-forms of ZTs led also to stronger competition with K+ ions, resulting in adsorption of this macronutrient and hence in a reduction of the fertilization value of the PS. In terms of heavy metals and other trace elements, all the treatments with ZTs had significantly increased the Li, Ba, Rb, Sr, Ga, and U content in the PS

Effects of natural and NH4-charged zeolite amendments and their combination with 3,4-dimethylpyrazole phosphate (DMPP) on soil gross ammonification and nitrification rates

No abstract availabl