Field assessment of soil biological and chemical quality in response to crop management practices

Abstract

Soil microbiological and chemical aspects were evaluated to determine the effects of conservation tillage and crop rotation on soil fertility over a 16-year period. A field trial was established to compare two cropping systems (continuous soybean and maize/soybean, soybean/maize rotation). In addition, maize (Zea mays L.) and soybean (Glycine max L., Merr) were grown in two different tillage systems: no tillage and reduced tillage. Soil populations of Trichoderma spp., Gliocladium spp. and total fungi were more abundant when maize or soybean were under conservation tillage and in the maize/soybean and soybean/ maize rotation, than in continuous soybean. Furthermore, higher levels of microbial respiration and fluorescein diacetate hydrolysis (FDA), were recorded under no tillage systems. However, soil counts of Actinomycetes and Pythium spp., and Pythium diversity together with soil microbial biomass were not affected by the field treatments. To establish a correlation with soil biological factors, soil chemical parameters, such as pH, organic matter content, total N, electrical conductivity, N-NO 3 -and P were also quantified, most of the correlations being significantly positive. Under no tillage there was a clear increase of the amount of crop residues and the C and N soil content due to the presence of residues. Also the distribution of crop residues in surface soil due to zero tillage and the quality of these residues, depending on the crop rotation employed, improved on soil biological and chemical characteristics. Crop yield was also enhanced by zero tillage through the management of residues. Although yield values were not directly associated with the development of microorganisms, both yield and microorganisms were influenced by crop management. These results suggest that measuring soil properties over a long period helps to define effective management strategies in order to preserve soil conditions.

Different Land Use Intensities in Grassland Ecosystems Drive Ecology of Microbial Communities Involved in Nitrogen Turnover in Soil

“…Recently, the effects of land use changes have been studied mainly focusing on (i) conversion of grassland to forest or vice versa [9], (ii) alterations in tillage management [10], [11], [12], (iii) changes in crop rotation [13] or (iv) modifications in fertilizer quality [14]. However, studies addressing questions related to consequences of changes in land use intensity on the soil microbiome are rare, although in many parts of the world we are facing a tremendous increase in land use intensity, due to the demands of bioeconomy (production of food, feed, fuel and fiber).…”

Conservation Agriculture and Soil Quality– An Overview

“…Hence, the higher the values of FDA hydrolysis are a sign of positive soil health and microbial activity. Vargas et al, 2009 had been noticed higher levels of fluorescein diacetate (FDA) hydrolysis under ZT than CT systems. Likewise, higher activities of FDA hydrolysis also noticed by Seifert et al, 2001.…”

Evaluation of Soil Quality in Relation to Landuse Effect in Akamkpa, Cross River State – Nigeria

“…Soil pH was determined in 1:2.5 soil-water slurry, using a combination glass electrode. Total carbon (C T ) and Nitrogen (N T ) contents were determined by Walkley and Black method as modified by [37,48]. Exchangeable bases: Ca, Mg, Na, K, were extracted using normal ammonium acetate (Thomas, 1982).…”

“…The effective cation exchange capacity (ECEC) varied from 3.98-10.21Cmolkg -1 . These values is indicative of the low capacity of these soils to retain nutrient elements due to the insufficient amount of organic matter and soil pH chemistry [43,[46][47][48][49][50]. The values of SAR and EA (Sodium Absoption Ration and Exchangeable Acidity) were considerably higher in the reforested lands than the natural forests.…”

“…This results may be due to the sensitive response of microbial biomass C to conversion of natural forest and cropping areas. Higher proportion of microbial biomass (C TMB and C AMB ) is an indication of aggregation of available organic carbon in soils [41][42][43][44][45][46][47][48][49][50][51]. The respond pattern of C TMB and C AMB to landuse change types were highly congruent, Basal respiration (BR) rates vary significantly among landuse change types, but was higher in soils under fallow and reforested lands and lower in built-up areas and soils around quarry mines.…”