Effects of three fertility amendments on soil dehydrogenase activity, organic C and pH

Abstract

. 1997. Effects of three fertility amendments on soil dehydrogenase activity, organic C and pH. Can. J. Soil Sci. 77: 281-283. An Acadia silty clay and a Pugwash sandy loam were each fertilized with three rates of either composted chicken manure, fresh chicken manure, or synthetic fertilizer. The effects of these amendments on soil microbial activity (dehydrogenase enzyme activity, DHA), organic C and pH were monitored. The sandy loam soil, which was relatively high in organic C, did not experience increases in DHA due to organic amendments while compost produced higher DHA than manure or fertilizer treatments to the silty clay soil. There was no treatment effect on soil organic C in the sandy loam, while organic treatments increased organic C in the silty clay soil. Soil pH was affected by treatments to both soils with compost amendments producing the greatest increases in this parameter. The results emphasize the importance of considering initial soil organic C and soil texture when planning studies of the effect of organic amendments on soil microbial activity. Le loam sableux, relativement riche en C organique, ne manifestait pas d'intensification de la DHA due aux amendements organiques, mais dans l'argile limoneuse le fumier composté donnait lieu à une plus forte DHA que le fumier frais ou que la fumure minérale. Aucun traitement n'avait d'effet sur la teneur en C organique dans le loam sableux, mais dans l'argile limoneuse un accroissement était observé dans les traitements avec amendements organiques. Le pH des deux sols, était touché par tous les traitements, le fumier composté provoquant les plus forts accroissements. Ces observations mettent en relief l'importance de la prise en compte à la fois de la teneur initiale de C organique dans le sol et de la texture du sol dans la planification des recherches sur les effets des amendements organiques sur l'activité microbienne du sol.Mots clés: Déshydrogénase, fumier composté, fumier de volaille frais, pH, carbone organique du sol Beginning in the summer of 1991, a 3-yr experiment was initiated to assess the impacts of fresh and composted chicken manure and ammonium nitrate as N sources for established hay crops. Various soil and plant parameters, including soil pH, organic carbon and DHA, were measured for the 3 yr [for a full report on the experiment's influence on all soil and plant parameters, refer to Warman and Cooper (1994)]. Microbial activity and its related factors were of particular interest because in systems which use organic fertility sources, it is the microbial turnover of soil organic matter which determines nutrient flow to the crop. Goyal et al. (1993), for example, reported that soils with higher levels of organic C have larger pools of microbial biomass which affect the flux of plant nutrients and the size of the plant nutrient pool.The DHA is considered one of the better indicators of microbial activity because dehydrogenases only occur within living cells, unlike other enzymes which can occur in an extracellular state. However, inter...

Nitrogen oxide emissions and soil microbial activities in a Japanese andisol as affected by N-fertilizer management

“…2). Increased nitrification activity (Nishio and Fujimoto 1990;Shi and Norton 2000) and dehydrogenase activity (Cooper and Warman 1997) with increasing addition of mineral NH4 + were also reported in some other studies. We observed that the nitrification and dehydrogenase activities showed similar temporal variations to those of the NO emission (Figs.…”

“…Soil dehydrogenase activity is considered to be one of the best indicators of microbial activity because the activity of this enzyme only occurs within living cells, unlike that of other enzymes that can occur in the extracellular state (Cooper and Warman 1997). Serra-Wittling et al (1995) indicat-This experiment was conducted in maize field plots to study the effects of N-fertilizer management on nitrogen oxide emissions, soil microbial activities and crop yield, and the relationships among them in a Japanese Andisol.…”

“…Soil dehydrogenase activity is considered to be one of the best indicators of microbial activity because the activity of this enzyme only occurs within living cells, unlike that of other enzymes that can occur in the extracellular state (Cooper and Warman 1997). Serra-Wittling et al (1995) indicat-ed that the dehydrogenase activity is a reliable indicator of global microbial activity.…”

Impact of natural or industrial liming materials on soil properties and microbial activity

“…Extracellular enzymes are very dependent on soil aggregates and the surrounding pH, making interpretation of results more complex because microenvironments are numerous and spatially distributed in soils (Tabatabai 1994). The dehydrogenase enzyme is thought to be a good indicator because it occurs only in living cells, unlike other enzymes such as phosphatases, which may occur in an extracellular state (Cooper and Warman 1997). However, there is no enzymatic test that can act as the best indicator of soil quality (Nannipieri and Landi 2000).…”

Microbial biomass C and alkaline phosphatase activity in two compost amended soils

“…Serra-Wittling et al (1995) observed a greater enzymatic activity with a young municipal solid-waste compost than with an older one. In the humid Canadian Atlantic region, Cooper and Warman (1997) reported that chicken manure compost significantly increased dehydrogenase activity in a low organic matter silty clay soil, but had no effect on a sandy loam that originally was richer in organic matter. The impact of compost on biochemical activities may, therefore, be dependent on inherent soil properties and compost characteristics.…”