Dynamics of Mineral Nitrogen in Soils Treated with Slow‐Release Fertilizers

Abstract

In this study, five different slow-release fertilizers were incubated in two soils, and their nitrogen (N) dynamics was followed for 4 months. Four of the fertilizers used were organic: two were hydrolyzed fur, one was made by hydrolyzed fur, farmyard manure, horn, and hoofs (Endurance), and one contained synthetic organic N [isobutylidendiurea (IBDU)]. The fifth, on the contrary, was a mineral fertilizer (Entec 26) containing both nitrate (NO 3 2 ) and ammonium (NH 4 þ ) and a nitrification inhibitor (3,4 DMPP). The two soils used were a sandy loam (SL) and a clay loam (CL). The fertilizer-N release was conditioned by both the fertilizers and the soil characteristics. The highest accumulation of mineral N as NO 3 2 was observed in the SL soil for all the treatments. The lowest net N release was observed in both soils with End, which was found to be the most resistant to microbial attack and degradation. The two fur-based fertilizers released similar amounts of N, which was higher in the SL soil than in the CL soil. The highest accumulation of fertilizer-derived N in the CL soil resulted from IBDU; however, the net accumulation of N in the SL soil with this fertilizer was even higher than the amount of N initially added. This fact was attributed to an increase in mineralization of the soil's native organic N. A real positive "priming effect" was also observed in the SL soil with E26. On the contrary, E26 caused a low level of N accumulation in the CL soil.

The effects of organic and conventional fertilizers on cereal aphids and their natural enemies

“…Both conventional and organic fertilizers have been shown to improve yields in cereals as a result of increased nitrogen availability and this is true for both manures (Sieling et al , 2006) and horn meal (Juroszek et al , 2004). The availability of nutrients from organic slow‐release fertilizers, however, is dependent on nitrogen mineralization (Dawson et al , 2008), the rate of which is determined by the carbon : nitrogen ratio, soil pH, soil structure and soil organic matter (Gioacchini et al , 2006) and may be limiting in organic systems. With conventional fertilizers, soil mineral nitrogen, such as ammonia, is very high immediately after application (Gioacchini et al , 2006).…”

Carbon (δ13C) and nitrogen (δ15N) stable isotope composition in plant and soil in Southern Patagonia's native forests

“…At drier sites, however, woody plants may also be more forced to re-utilize water from lower soil depths (Caldwell & Richards, 1989;Caldwell et al, 1998;Jackson et al, 2000;Nie et al, 2011). Usually, d 15 N values of soils increase with soil depth, because of various stable isotope fractionation processes that accompany N uptake and loss (Delwiche et al, 1979;Yoneyama, 1996;Gioacchini et al, 2006). An increased utilization of subsoil N will thus also result in an increased uptake of heavier N into plant foliar biomass, resulting in higher d 15 N ratios in the leaves and, when returned to soil, also in the surface soil.…”

Soil Application of Tannery Land Plaster: Effects on Nitrogen Mineralization and Soil Biochemical Properties

“…Plant availability of organic N in a biosolid mainly depends on soil microbial processes of mineralization and immobilization whose turnover is mainly influenced by its C : N ratio, although the soil N turnover cannot be explained by this parameter alone. Soil chemical-physical characteristics and biosolid properties such as soluble C content, N biochemical quality, and phenolic content could play a crucial role in determining N mineralization [12][13][14][15][16]. Specific studies on the mineralization dynamic of the organic N in biosolids are therefore required in order to evaluate N supply to plants and to avoid leaching of N in the environment.…”