Influence of lime, fertilizer and manureapplications on soil organic matter content and soilphysical conditions: a review

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• 作者：Haynes ; R.J. ; Naidu ; R.
• 关键词：dispersion ; fertilizers ; flocculation ; lime ; manures ; soil organic matter ; soil physical properties
• 刊名：Nutrient Cycling in Agroecosystems
• 出版年：1998
• 出版时间：1998
• 年：1998
• 卷：51
• 期：2
• 页码：123-137
• 全文大小：352 KB

文摘

The effects of lime, fertilizer and manureapplications on soil organic matter status and soilphysical properties are of importance to agriculturalsustainability. Their effects are complex and manyinteractions can occur. In the short-term, liming canresult in dispersion of clay colloids and formation ofsurface crusts. As pH is increased the surfacenegative charge on clay colloids increases andrepulsive forces between particles dominate. However,at higher lime rates, Ca$^2+$ concentrations andionic strength in soil solution increase causingcompression of the electrical double layer and renewedflocculation. When present in sufficient quantities,both lime and hydroxy-Al polymers formed byprecipitation of exchangeable Al, can act as cementingagents bonding soil particles together and improvingsoil structure. Liming often causes a temporary flushof soil microbial activity but the effect of this onsoil aggregation is unclear. It is suggested that, inthe long-term, liming will increase crop yields,organic matter returns, soil organic matter contentand thus soil aggregation. There is a need to studythese relationships on existing long-term limingtrials.

Fertilizers are applied to soils in order to maintainor improve crop yields. In the long-term, increasedcrop yields and organic matter returns with regularfertilizer applications result in a higher soilorganic matter content and biological activity beingattained than where no fertilizers are applied. As aresult, long-term fertilizer applications have beenreported, in a number of cases, to cause increases inwater stable aggregation, porosity, infiltrationcapacity and hydraulic conductivity and decreases inbulk density. Fertilizer additions can also havephysico-chemical effects which influence soilaggregation. Phosphatic fertilizers and phosphoricacid can favour aggregation by the formation of Al orCa phosphate binding agents whilst where fertilizerNH$\_4$$^+$ accumulates in the soil at highconcentrations, dispersion of clay colloids can befavoured.

Additions of organic manures result in increased soilorganic matter content. Many reports have shown thatthis results in increased water holding capacity,porosity, infiltration capacity, hydraulicconductivity and water stable aggregation anddecreased bulk density and surface crusting. Problemsassociated with large applications of manure includedispersion caused by accumulated K$^+$, Na$^+$ andNH$\_4$$^+$ in the soil and production ofwater-repellant substances by decomposer fungi.