Imaging-optode measurements of ammonium distribution in soil after different manure amendments

Abstract

The choice of manure application technique can affect both the spatial distribution of ammonium in soil and net nitrogen (N) mineralization, and thereby N availability to crops. In this study we compared net N mineralization and spatial ammonium distribution after different degrees of incorporation of solid chicken manure and cattle slurry into soil. Ammonium-specific fluorescing optodes were assembled with manure applied to soil in closed chambers and the spatial distribution of ammonium in different treatments was measured for 2 weeks. The results indicated that much ammonium from the manures was quickly adsorbed to clay particles. Consequently, the ammonium concentration in the soil solution was threefold higher in the sandy soil than in the clay soil studied. Ammonium was distributed over a larger soil volume from manure applied below the soil surface than from manure applied above. Because the optodes excluded ammonium adsorbed to soil particles, net N mineralization was instead studied in separate incubations using extraction with potassium chloride solution for determination of ammonium and nitrate. When manure was kept concentrated in lumps rather than being mixed with soil, nitrate levels were about five times smaller after 1 week and 5-10% more of the manure N occurred as mineral N after 2 weeks. There were no differences in net N mineralization between surface application and subsurface incorporation. In this study a new technique to visualize and measure ammonium patterns around manure in soil proved to be useful for evaluating ammonium distribution and adsorption, but net N mineralization required incubations.

Optimal Placement of Meat Bone Meal Pellets to Spring Oats

“…Baitilwake et al (2012) found greater immobilization and nitrification after soil incorporation than surface application of chicken and cattle manure. However, Delin and Strömberg (2011) did not find any differences in net mineralization of nitrogen between surfaceapplied and incorporated chicken manure and cattle slurry, as long as the manure was kept in concentrated lumps, although when the manure was mixed with a larger soil volume both net immobilization and nitrification increased.…”

“…Band application would probably still be as successful as in 25 cm spacing, as long as pellets are not put together with the seeds. The benefit could be because of more efficient incorporation and lower immobilization (Sørensen and Jensen, 1995;Delin and Strömberg, 2011).…”

Two decades of chemical imaging of solutes in sediments and soils – a review

“…The HPTS(TOA) ion pair, immobilized in ethyl cellulose, is to date the only indicator reported to be used for planar optode imaging of pCO 2 [20,72]. The polarity-sensitive fluorescent indicator merocyanine 540 (MC540) has been developed and applied for NH 4 + imaging [74,[132][133][134]. The sensing system relies on a co-extraction technique [135], where the sensor matrix is based on a two phase system, containing a hydrogel (NH 80/92) and non-polar ether emulsion droplets.…”

“…Quantification of the NH 4 + concentration is made through a dual-excitation dual-emission ratiometric imaging approach [132]. Using timecorrelated pixel-by-pixel calibration [74,127] this sensor was stable for up to 10 days at concentrations from 0 to 500 mmol L À1 [74,134].…”

Signal Enhancements in Plasmon Assisted Fluorescence Ratiometric Imaging Optodes

“…Also the analytical performance such as sensitivity, limit of detection (LOD), and expected operational lifetime were calculated for each pixel and presented as statistical images [9]. After improvements of the infinity corrected imaging system as well as a high throughput macro imaging techniques were developed [10], the technique was ready for research applications such as studying ammonium uptake close to roots [11], and multiple fertilizer release studies (using a high throughput imaging system) in different soils [12] over long time periods up to 11 days.…”