Abstract: Provided in the invention is a stabilized fertilizer composition (I) suitable for use in fertilizers and comprising: Urea (a), One or more compounds (b), One or more urease inhibitors (c1) and/or one or more nitrification inhibitors (c2), optionally provided in one or more carriers (d), said compounds (c) being different from compounds (b), Optionally one or more additives (e) different from any of the above, and Water (f) in an amount less than about 10 wt % and preferably less than about 5 wt %; wherein compounds (b) are selected from thiosulfates (b1) and/or from polysulfides (b2) and/or from (bi)sulfites (b3); and wherein the ratio of urea (a) to compounds (b) is from 1:99 to 99:1, preferably from 2:98 to 98:2. Products of the invention can be made in various forms and in different ways. All of the materials of the invention are suitable for use in fertilizers and blend well with solid and liquid fertilizers standardly used. They have excellent shelf life and provide good urea-N protection.

Abstract: Provided in the invention are thiosulfate-urea based products (IIa) and/or a polysulfide-urea based products (IIb) and/or a (bi)sulfite-urea based products (IIc) suitable for use in fertilizers and comprising: one or more urea-containing compounds (a), one or more compounds (b), optionally, one or more urease (c1) and/or nitrification (c2) inhibitors that are different from compounds (b), and/or optionally, one or more additives (d) that are different from any of the above compounds, wherein the amount of water (e) in the product (II) is less than about 10 wt %, preferably less than about 5 wt %, wherein compounds (a) are selected from urea (a1) and/or from urea-aldehyde products (a2) and/or from urea-triazone compounds (a3), wherein compounds (b) are selected from thiosulfates (b1) and/or from polysulfides (b2) and/or from (bi)sulfites (b3). An advantage of products of the invention is that only minimal amounts of degradation products of compounds (b) are formed.