Controlled Release of Fertilizer Minerals by Incapsulating Membranes: II. Efficiency of Recovery, Influence of Soil Moisture, Mode of Application, and Other Considerations Related to Use

Abstract

It was shown using membrane‐coated granular fertilizer, in which the membrane constituted 11 or 12.5% of the weight of the granules, that: (a) moisture levels, exceeding the range of permanent wilting percentage to field capacity in a loam soil, did not appreciably affect the rate of transfer of minerals through the membrane of coated fertilizer mixed in the soil, (b) the time for transfer of a given fraction of fertilizer through membranes is substantially extended if the fertilizer is topdressed on a soil as compared to incorporated (presumably due to intermittent drying between leachings), and (c) an efficiency of recovery ranging from about 25 to 45% was obtained from a single application, incorporated in the sand, of coated ammonium nitrate by corn during a 3‐month growing period. In the latter study a sand was used containing < 1% of clay and as much as 7 feet of water passed through the root zone during the period of the study. Implications of the coating technique for controlling fertilizer availability are briefly considered.

Nitrogen Release from Environmentally Smart Nitrogen Fertilizer as Influenced by Soil Series, Temperature, Moisture, and Incubation Method

“…However, when soil moisture was below permanent wilting point, N-release rate was reduced due either to very slow nutrient diffusion across the coating or moisture was inadequate to dissolve the fertilizer. Results from our study and those from Christianson (1988) and Lunt and Oertli (1962) show that soil moisture influences only the time of initial release and not the release rate across time for three different polymer-coated fertilizers.…”

“…Moisture plays less of a role in N release from polymercoated urea primarily because soil humidity remains high, near 100%, when soil moisture levels are below field capacity (Christianson 1988). Lunt and Oertli (1962) reported that within the range of permanent wilting point to field capacity, soil moisture had no practical effect on N release from a coated fertilizer. However, when soil moisture was below permanent wilting point, N-release rate was reduced due either to very slow nutrient diffusion across the coating or moisture was inadequate to dissolve the fertilizer.…”

Nutrients Release from a Novel Gel-Based Slow/Controlled Release Fertilizer

“…However, by this G-CRF, both temperature and soil moisture were main factors to affect nutrient release rate which would affect dispersion of fertilizer granules, effective cross section area of ion diffusion, and other physical/chemical processes in soil. In fact, by the CRFs in which a physical barrier controls the release easily affected by both soil moisture and temperature, such results have been tested in some studies and indicated that the nutrient releases rates of CRFs increased with improvement of the soil moisture and temperature [29][30][31][32]. In this experiment, the G-CRF showed obviously delaying release effects when soil moisture and temperature were below 45% (w/w) and 35 ∘ C, respectively.…”

Enhanced Efficiency Fertilizers for Improved Nutrient Management: Potato (Solanum tuberosum)

“…The concept of CRN and SRN fertilizer materials is not new (2,8,40), but previous work has been mostly unsuccessful in potatoes. Fertilizer costs were high and N release was too early, too late, and/or too unpredictable, resulting in delayed tuberization and yield loss (10,30,36,37,38,43,81).…”