Effects of cattle slurry and cultivation on infiltration in sandy and silty soils from northern Norway     

Trond K. Haraldsen  Tore E. Sveistrup 《Soil & Tillage Research》1994,29(4)

The study was conducted on virgin (uncultivated) and cultivated bare sandy and silty soil monoliths to investigate the infiltration rate before and after application of cattle slurry. Both soils had higher infiltration rates in the virgin state than in the cultivated state. Application of either 50 Mg ha⁻¹ fresh or aerated slurry to the soil surface caused a significant decrease in infiltration rate which lasted for 3 months. No significant difference in infiltration rate was found between fresh and aerated slurry. The application of slurry decreased the infiltration rate most on the virgin sandy soil. Only a small decrease was recorded, owing its to low initial infiltration rate on the cultivated silty soil. The infiltration rate before slurry application was positively correlated with air-filled porosity at −5 kPa matric potential and negatively correlated with soil on ignition. After slurry application the infiltration rate was positively correlated with soil air-filled porosity and negatively correlated with slurry dry matter content.  相似文献   

Farmer‐led maize biochar trials: Effect on crop yield and soil nutrients under conservation farming          下载免费PDF全文

Vegard Martinsen  Jan Mulder  Victor Shitumbanuma  Magnus Sparrevik  Trond Børresen  Gerard Cornelissen 《植物养料与土壤学杂志》2014,177(5):681-695

In extensive farmer‐led trials practicing conservation farming (CF) in three regions of Zambia (Mongu: sandy soils; Kaoma: sandy or loamy sand soils; Mkushi: sandy loam or loamy soils), we studied the effects of biochar made of maize cobs (0, 2, and 6 t ha^?1 corresponding to 0, 0.8, and 2.5% per basin) at different fertilizer rates of NPK and urea on crop yield of maize (Zea mays) and groundnuts (Arachis hypogaea). Conservation farming in this case combines minimum tillage (how basins), crop rotation and residue retention. For the first time, the effect of biochar on in situ soil nutrient supply rates [determined by buried Plant Root Simulator (PRS?) exchange resins] was studied, as well as the effects of biochar on elemental composition of maize. Effects of 0–10% (w:w) biochar addition on soil physical and soil chemical properties were determined in the laboratory. At all sites there was a consistent positive response in crop yield upon the addition of biochar. However, due to a great variability between farms there were no significant differences in absolute yields between the treatments. In the sandy soils at Mongu, relative yields (i.e., percentage yield with biochar relative to the same fertilizer rate without biochar) of maize grains and maize stover were significantly increased at recommended fertilizer rates (232 ± 60%) and at half the recommended rate (128 ± 6%), respectively. In addition, biochar significantly increased concentrations of K and P in maize stover. In situ soil nutrient supply rates as measured by PRS?‐probes were highly spatially variable with no consistent effects of the different treatments in the three regions. By contrast, the fraction of plant available water (Vol.‐%) significantly increased upon the addition of biochar in all three soils. The increase caused by 10% biochar addition was of factor 2.5 in Mongu (from 4.5% to 11.2%) and 1.2 in both Kaoma (from 14.7% to 18.2%) and Mkushi (from 18.2% to 22.7%). Cation exchange capacity, pH, and exchangeable K significantly increased upon the addition of 10% (w:w) biochar in all three regions with a subsequent increase in base saturation and decrease of available Al³⁺. Our findings suggest that the addition of biochar in combination with CF might have a positive impact on crop growth and that this positive effect is mainly caused by increases in plant‐available water and decreased available Al.  相似文献   

Carbon mineralization, fungal and bacterial growth, and enzyme activities as affected by contact between crop residues and soil   总被引：18，自引：0，他引：18  

Trond M. Henriksen  Tor A. Breland 《Biology and Fertility of Soils》2002,35(1):41-48

The degree of contact between crop residues and the soil matrix, as determined by the method of residue incorporation, affects decomposition dynamics both under natural and experimental conditions. In microcosm experiments we tested the hypothesis that poor residue-soil contact reduces the decomposition of structural plant constituents through delayed colonization by microorganisms degrading cellulose and hemicellulose. Barley straw or red clover foliage was either confined in buried mesh bags or homogeneously mixed into a loamy topsoil or a silty subsoil to create poor or intimate residue-soil contact in microbiologically rich and less rich environments, respectively. Soil type had no effect on decomposition of the easily degradable clover residues, but cumulative mineralization of barley straw C after 52 days at 15°C was less in the subsoil than in the topsoil by 12% of initial C. For clover material, poor soil contact increased cumulative C mineralization by 5% of initial C in the loamy topsoil but had no effect in the silty subsoil. For the more slowly degradable, cellulose- and hemicellulose-rich straw, on the other hand, poor soil contact reduced C mineralization by 6% of initial C. The results from the loamy topsoil were confirmed in a second experiment in a sandy topsoil. The reduced decomposition of straw with poor soil contact could not be explained by less favourable abiotic conditions, N deficiency nor exclusion of larger animals by mesh bags. Reduced straw-soil contact delayed measured increases in fungal ergosterol concentration, ratio of fungal to bacterial substrate-induced respiration, number of cellulase-producing, colony-forming bacterial units and activity of cellulases and hemicellulase on the residues. Thus, the results supported our hypothesis and underscore the importance of ensuring representative conditions for the soil microflora when decomposition dynamics are studied in microcosms experiments designed to mimic field conditions.  相似文献