Dataset from an investigation of the effect of natural zeolite particle size reduction as a material for the manufacture of slow-release potassium fertilizer in oil palm seedlings growth with peat soil planting media.

Particle size is one-factor influencing zeolite's ion exchange properties. This study used natural zeolite with a particle size of ±0.147 mm and ±500 nm as a carrier for K-zeolite-based fertilizer. K in the zeolite-based fertilizer was expected to be released slowly and more effectively in supplying K for oil palm seedlings on peat soil media compared to conventional K fertilizer (Muriate of Potash, or MoP). The study was arranged using a completely randomized design (CRD) with eight treatments and three replications. The treatments tested were: (1) control/no fertilization; (2) MoP fertilizer; (3) fine-polite-fertilizer formula-1 (FPF-1); (4) fine-polite-fertilizer formula-2 (FPF-2); (5) fine-polite-fertilizer formula-3 (NPF-3); (6) micro-polite-fertilizer formula-1 (MPF-1); (7) micro-polite-fertilizer formula-2 (MPF-2); and (8) micro-polite-fertilizer formula-3 (MPF-3). K zeolite-based fertilizers generally had better effectiveness than MoP, where formula 2 (50 % zeolite: 50 % MoP fertilizer) was the best among the three K zeolite-based fertilizer formulas. There were no significantly different effects of zeolite with a particle size of ±500 nm and ±0.147 mm on the growth and K uptake of oil palm seedlings and the amount of leached K from the peat soil. This data set could be helpful for researchers who want to develop an environmentally friendly fertilizer to implement sustainable agriculture.

Varying redox potential affects P release from stream bank sediments.

Sediments in streams that drain agricultural watersheds may be sinks that can adsorb P from the stream or sources that can release P to the stream. Sediment characteristics and environmental factors, including the oxidation-reduction (redox) potential of the water associated with the sediment, determine whether P will be adsorbed or released by the sediment. We investigated P adsorption and release by four sediments [three Holocene-age sediments (Camp Creek, Roberts Creek and Gunder) as well as Pre-Illinoian-age Till] that occur in Walnut Creek, a second-order stream in Jasper County, Iowa, that is representative of many small streams in the glaciated upper Midwest of the US. The effects of two redox potentials on phosphorus buffering capacity (PBC) and equilibrium phosphorus concentration (EPC) were evaluated in batch adsorption experiments. We also simulated aerobic and anerobic conditions over a 24-day period and measured solution-phase P concentrations in stirred systems where the sediments were isolated from the water by dialysis tubing. The batch experiment indicated that the EPCs of the three Holocene-age sediments were similar to one another and increased with decreasing redox potential. In the stirred flow reactors, more dissolved P was released from the Camp Creek and Roberts Creek sediments under anaerobic conditions than from the other sediments. This observation suggests that these two sediments, which are younger and higher in the stratigraphic sequence, are more likely to be P sources in suboxic settings. The P buffering capacity was greatest in the till. Where it is in contact with the stream water, the till is likely to serve as an adsorbing sink for P in the water column.