What is the importance of soil PH?

-


It's the most important single property identifying the chemical character of the soil.It not only controls the sorption & distribution of various cations bu soil colloids but also controls the release of bases from the exchange complex.The immediate & direct effects of PH within the range PH8-PH4.On plant growth are negligible ,given that all other environmental features are equal.there are many second-order effects which contribute to a correlation between plant performance & PH of soil.Soil PH helps in determining the following:
1)Soil toxicity indicator:-The most widespread  elemental toxicity is that of alluminium,which is toxic to many plants at concentrations >1ppm in soil water.Aluminosilicate lattices collapses progressively at low PH resulting in increasig activity of Al3+ ions (markedly below PH5) saturatig the base exchange system.Most metal toxicities are greatest at low PH.The substrate may remain sufficiently toxic to prevent plant growth even when acidity is reduced to PH>7 by lime use.Fe & Mg also become more available at low soil PH but their toxicity depends on oxidation state.The other family of toxic metals are cu,zn,Pb etc.Soil PH however itself is a complex set of toxicity controlling factors.
2)base status:-Although it is allied to fertility but it is related also directly to PH in more simple fashion than any other component of nutrient availability.
3)Soil fertility:-Agriculture is only concerned with regulating the soil environment to allow optimum production of few selected plants.However,ecosystems are found on soils across the PH range indicated & even further into the acid end of the spectrum.The effect of carbon-di-oxide on PH of pure water system is seen to entail a reduction in PH from about PH 6.2 with atmospheric influence of roots & soil organisms in PH reduction can't be neglected also.When calcium carbonate  is introduced the aforesaid system can be represented as:-
                                                                
                                                                  



under carbon-di-oxide regime decalcification leads to PH fall.Soil alkalinity greater than encountered in calcareous soils only occurs when Na is present.When soil is 15% base saturated with Na,PH may be between 8.5-10.
         In conclusion,it can be stated that tendency between soil PH & fertility for simple correlations are absent.Troug's Diagram on qualitative nutrient availability also assumes that an optimum quantity of nutrient elements is present but in ecological situations it's untrue.Thus,preventive measures can be taken to check soil toxicity once soil PH has been determined.Moreover,it may help us in study of plant species which thrive in different values of soil PH.it also helps us in establishing a relationship between climate & soil PH.It also helps us in establishing a relationship between climate & soil PH of that region

Comments

Post a Comment

Popular posts from this blog

Distinguish between barotropic & baroclinic conditions of the atmosphere

-
An air mass which is defined as a large body of air whose physical properties especially temperature, moisture & lapse rate are more or less uniform horizontally for hundreds of kilometers.                             barotropic condition of atmosphere is theoretically ideal condition where surfaces of constant pressure are not intersected by isostereic(constant density) surfaces, so that in a vertical cross-section isobars(imaginary lines joining places of equal atmospheric pressure) & isotherms appear parallel i.e,zero baroclinicity.It is a rare phenomenon & is found in case of frontogenesis,separated by baroclinic front zone.          Baroclinic condition of atmosphere is seen in comparatively narrow zones (perhaps 1000Km. in width) of thermal discontinuity also known as fronts in air mass property. They are belts of sharp meteorological gradient recognized as distinct factors in the origin of mid-latitude disturbances. The instability is associated with rising wa
Read more

Airtel DTH: Error B001/Error B003 and Why I left Airtel possibly for Better

-
Image
Why did I decided to Leave?  It has been 2 weeks since I complained about B001 error and Airtel in between replaced 2 set top boxes but problem remained. I have replaced everything as per "diagnosis" of airtel DTH technician but no solution could be reached. Currently, my balance has been deducted from INR200 to INR 10. There are discrepancies with the bills issued against parts replacements conducted during this period. It must be stressed here that I as a customer felt cheated, neglected, harassed by Airtel +Service Partner and I was a 7-8 years+ customer. We never saw that set top box seals were broken in front of our eyes for both the replacements by technicians. My comparison chart for new service provider
Read more

Why do isotherms shift north & south from season to season?

-
An isotherm is an imaginary line drawn on a weather chart or map to join places of equal temperature. Temperature varies from season -as there is high temperature during summer & low temperature during winter with minor changes during transitionary seasons. We know that temperature is proportional to atmospheric pressure & inversely proportional to density.                                                        A.P.=K*D*T                                                           T=A.P*1/D where,A.P.=atmospheric pressure;K=constant;D=density;T=temperature      During the summer season in either of the hemisphere's the sun is vertically overhead of the tropic of cancer/capricorn.The land which has a low specific heat capacity & also being a bad conductor of heat re-radiates the heat to the atmosphere resulting in the spreading of molecules of atmospheric gases due to the heat energy. As molecules spread over a wide region it's pressure on the land becomes l
Read more