The use of ash as a fertilizer for the agricultural production could return a considerable amount of nutrients removed in wood. Harvest back to the natural cycle. Furthermore, oxides of alkaline and earth alkaline cations formed in the burning process exert a liming effect and counteract soil acidification. However, heavy metals  acumulated in the ash especially cadmium (Cd), have caused concern for environmental risks. Cadmium concentrations in ash typically vary between 1 and 20 ug g-1 ash (Korpilaht, et al., 1998) and often exceed the level allowed for fertilizers used in agriculture (Evald) 1998. 

The environmental risks caused by the ash do not only depend on the total concentration of cadmium but also on its dissolution rate. When dissolved to soil solution cadmium is easily taken up by plants and enriched especially in protein compounds where it replace, Zinc. At high concentrations it also may disturb micro-biological processe and thus, affect the nutrients cycling. Many of the cadmium compounds are relatively mobile in the soil and readily taken up by plant (Kabata-Pendias and Pendias, 1984;, Lund Borg, 1998; Stevenson and Cole, 1999). The most important soil factors governing the uptake are pH and the amount of organic matter (Christensen; 1989; Odenius and Autio 1989). Also microbial processes should be considered if cadmium containing ash is used as a forest fertilizer (Fritze et al., 2000).  

            Metal concentrations in ash depending on the burning and granulation processes as well as on the particles size fraction (Obernberger et al.,1997; Dahl and Obernberger, 1998). The solubility of cadmium in the ash is dependent on its chemical form, but the dominating form in the different kinds of ashes have not been completely identified (Nordin and Ackman, 1998). Therefore, the risk assessment cannot be based merely on the total cadmium concentration, but more detailed information on reaction patterns cadmium denved from various ash types in various soil types is needed.

Physical Characteristics of Soil Amended With Ash
            According to Mbah et al., (2009) reported that effect of ash on soil physical properties which greatly improved soil structure by making finer particle and improve soil colour, soil porosity and bulk density.

            The chemical properties of the soil amended with ash significantly increased soil organic matter, N,P,K, Ca, Mg, Fe and Zn. Also ash had high content of alkaline properties with pH of 12.7 and 15.6Cmol kg-1 of Ca.
            Exchangeable potassium (K) increased significantly (P<0.05) in the ash amended plots relative to the control plot. Since ashes are known to be of high potash content, the above observations are under-stable. This is in line with some previously reported observations that crop residue ash contained N,P,K Ca and Mg Odedina et al (2003), reported that ash contained as high as 12.36% K in its nutrient composition with Ca and Mg values of 3.40% and 0.76% respectively and this also agrees with Ogbodo (2009) that plot treated with crop residue. Ash contains significantly higher levels of exchangeable K, Ca, Mg, than other crop residue Ash specifically had liming effect on the soil owing to its higher Ca and Mg content. Moreover, the result underline the importance of ash in coping with high level of K leaching in this sub-humid tropical environment. The rise was essentially due to the production of K oxides hydroxides and carbonates, which did not persist through the next season.
            The ash-amendments significantly increased Mg2+ over the control in spite of Mg2+ (3.5 cmol kg-1) in the soil. It agrees also with Sobulo and Osiname(1989), who reported that low N. mighty be as a result of early mineralization of Nutrients  especially N for maize uptake. This also agrees with Sarmalm et al. (2001) and Arvidsson and Lundkrist (2003) who observed an increase in ash-amended soils of almost all the soil nutrients except Nitrogen.

Effect of the soil amended with Ash on maize grain yield
            The effect of the different ash sources on the shelled maize yield the result shows higher in grain in ash amended plot compared to the control plot irrespective of the sources of ash. The amended plot yielded higher than the non-amended plots. The result is in line the findings of Odiete et al., (2008). That the application of ash to  maize. Significantly increased the grain yield.

            Lime is a common amendment agent that is routinely applied to agricultural soils. The importance of lime or its effects exceeds improving fertility and increased plants nutrients but also boasters  of  good soil physical properties Pearzon (1975) discovered that on highly weathered acid soils of the tropics, lime rate are often based on neutralization of exchangeable of cations and this result in rise in soil pH values. in the range of 5-3-5-6. (Haynes 1984) disclosed that crop yield depression induced by lime usually involves the deficiencies of Mg, Sl, Cu, Zn, P.k. The flocculation phenomena are important condition that determine the effect of lime on soil physical proprieties (Summer, 1992) apart from ash which we have proven to be an effective liming agent there are others such as Gypsum which is a good option to raise calcium levels and greatly improve soil structure Vizcaayno (2001) told how gypsum has a liming influence on acid soil including its ability to improve drainage and aeration. 

Dolomite is an important and effective liming agent in agricultural production.

            When ash is applied to the soil and a resultant pH increase occur there is an evident shift in the microbial population from fungi to actinomycetes and to bacteria. Badagnicco et al., (1992) explained that liming increases microbial biomass content, soil respiration rate the microbial metabic respiration per unit biomass) soil enzyme activity dehydrogenate, sulphastes and protease activity and net mineralization of soil organic N and S.
            Burns and Davies (1986) discussed how liming could well have indirect effects on soil physical properties via its ability to increase crop growth, soil organic matter content and thus soil biological activities and such effects are usually seen as a major cause of improvement in soil tith. The main reason for liming acid soils is to improve crop growth and yield. The positive effect usually occur via amelioration of Al and sometimes Mn toxicity and or alleviation of Ca deficiency. Cheshire (1990) said that as a result of deposition of Ca large active microbial biomass develops in rhizosphere. As we earlier noted. The microbial biomass produces polysaccharides bindings agents and in addition root hairs and vesicular arbuscular microrhizae (VAM) has a enmeshing effect forming a three dimensional network which helps hold soil particles together to form stable aggregates.
            Hayce and Swift 1990 discussed how these complex poly-metric molecules are central to the formation of stable soil aggregate, and are synthesized by the decomposer microform during the decomposing process. Thus, the long term effect of liming may well be to increase soil organic matter content by increasing root and crop growth and thus, input or organic residue to soil and as a result soil physical condition particularly soil aggregation and aggregate stability are likely to improve.

            In as much as ash influences microbial activity. Liming can also increase the size and activity of earthworm population. Springtt and  Syers. (1984) found out that most earthworms in temperate agricultural soils prefer a pH of around 7 although the sensitivity of individual species vary (eg Apporectodea caliginosa). This pH (Stockdill and Cossens, 1966) showed that liming increases earthworm number and this is primarily a response to increase in pH rather than added Ca. Dockson and Van Wingerden (1964) reported that at a low or reduced pH value, earthworm would not only be reduced number but can go into dispenses more rapidly upon the onset of dry condition. An increased earthworm highest large amount of soil and organic debris mix them together and their cast may form the base for several stable aggregates particularly in pasture soils. The borrowing action of earthworm helps to increase the soil macro porosity.

            Wood ash is the residue powder left after the combustion of wood material and it has been found to be effective liming material due to the high cost of lime. It also has the potentials of supplying  plant nutrient like N, P, K Ca, and Mg,
Wood ash contains calcium carbonate as its major component, representing 25 or even 45 percent less than 10 percent as potash, and less than 1 percent phosphate. There are trace elements of iron, manganese, zinc, copper and some heavy metals. However these numbers vary as combustion temperature is an important variable in determining wood ash composition.
For a long time wood ash has been used in agricultural soil application as it recycle. Nutrients back to the soil. Wood ash has some value as a fertilizer. But does not contain nitrogen because of presence of calcium carbonate. It acts as a liming agent and will deacidity the soil increasing pH Potassium hydroxide can be made from wood ash.
Rice Husk ash is the powder that remain after rice husk has burial. This burnt rice husk contain valvable organic and in organic nutrients which have the potentials to improve the soil physical properties. Burnt rice husk ash contains about 0.45% N, 0.2% P and 0.4%K which is similar to 0.50, 0.25 and 0.50% N. P. K (Yarikar and Yayock 1987)

            Prior to the wood ash and burnt rice husk as cereals provide the basic for management of soil fertility. Burnt rice husk on the other side, have been regarded as a primary source of nutrient since the earliest of civilization. With the continuous application of this burnt rice husk, some properties of the soil are constantly affected.
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