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The effects of lime, fertilizer and manure applications on soil organic matter status and soil physical properties are of importance to agricultural sustainability. Their effects are complex and many interactions can occur. In the short-term, liming can result in dispersion of clay colloids and formation of surface crusts. As pH is increased the surface(More)
The effects of addition of a range of organic amendments (biosolids, spent mushroom compost, green waste compost and green waste-derived biochar), at two rates, on some key chemical, physical and microbial properties of bauxite-processing residue sand were studied in a laboratory incubation study. Levels of exchangeable cations were not greatly affected by(More)
Labile organic matter fractions (light fraction C, microbial biomass C and water-soluble organic matter) were extracted from two soils (Lismore silt loam and Temuka clay loam) varying in cropping history from long-term (>9 yr) arable cropping to long-term (>9 yr) pasture in the Canterbury region of New Zealand. With increasing periods under pasture, soil(More)
The processes responsible for maintenance of cation-anion balance in plants and their relation to active ion accumulation and changes in rhizosphere pH are outlined and discussed. The major processes involved are: (1) accumulation and degradation of organic acids which occur in the plant mainly as organic acid anions (and their transfer within the plant)(More)
High rates of lime and fertilizer-P are characteristically required to obtain high crop yields on highly weathered acid soils. Much of the agriculture in the southern tropical belt, where acid soils predominate, is carried out by resource-poor, semi-subsistence farmers who are unable to purchase large quantities of lime and fertilizer. There are, however, a(More)
The effects of adding lime and/or phosphate to an acid, phosphate-deficient soil on microbial activity, enzyme activities and levels of biomass and extractable N, S and P were studied under laboratory conditions. Following rewetting there was, as expected, an initial flush in microbial growth and activity, as shown by large increases in CO2 evolution, in(More)
 The effects of 5 years of continuous grass/clover (Cont grass/clover) or grass (Cont grass) pasture or 5 years of annual grass under conventional (Ann grass CT) or zero tillage (Ann grass ZT) were compared with that of 5 years of continuous barley (LT arable) on a site which had previously been under arable crops for 11 years. For added comparison, a(More)
The annual herbage dry matter yield, herbage P concentrations and quantities of P, K, Mg and Ca cycled by grazing sheep were calculated for a 37 year-old grazed pasture supplied with superphosphate at rates of 0, 188 and 376 kg ha-1 annually. The amount and distribution of inorganic and organic P and exchangeable K, Mg and Ca in the soil below the three(More)
Mispah type soil (FAO : Lithosol) contaminated with >250 000 mg kg-1 creosote was collected from the yard of a creosote treatment plant. The soils carbon, nitrogen and phosphorus contents were determined. Due to creosote contamination, thecarbon content of the soil was found to be 130,000 mg C kg-1. This concentration was found to greatly affect the(More)