Study On The Indications Of Dictyostelids For Farmland Soil Environment Changes

The black soil quality has degenerated seriously, the ability of protecting fertilizer and water in the soil reduces obviously, Therefore the goal Of researching quality and health of balck soil has very important significance to the development of Northeast corn area in china. The soil animal is very sensitive to the environmental variation, the community structure assumes the regular seasonal variation, but the year changes assume relative stabilization, the growth and reproduction speed is fast, moreover the overwhelming majority protozoon's species distribute worldwidly, thus the reliability and comparability of the data enhances greatly, therefore we can study one kind of animals which can instruct the black soil ablity and environmental variation more effectivly, thus promotes the development of Northeast corn area in our country.This article takes the Dictyostelids as the indicator, it has the netted handle and the individual is big, its life cycle is short, but we can see it directly with the naked eye, moreover its myxamoeba can reflect soil environment changes sensitively,the pH value,temperature,moisture content,organic matter air space of the soil all influence it tremendously. This earlier period of the experiment has gathered massive soil samples, wu culture Dictyostelids from this samples. The Dictyostelids which gathered have carried on the type appraisal,quantity statistics and frequency statistics,the results proof that Dictyostelids distribute widespread in Northeast. Later period of the experiment has inspected the response of the Dictyostelids to soil organic content,the soil physics environmental variation and the soil chemistry environmental variation. Finally we proof that Dictyostelids can be the the indicator of the soil environmental variation. The results are as follows:(1) We appraise four kinds of Dictyostelids from the samples, of three species are Chinese known kinds,of one plant is the domestic new record.The chinese known species are Dictyostelium giganteum singh,Dictyostelium minutum Raper and the Dictyostelium sphaerocephalum (Oud.)Sacc.et March, the domestic new record is Dictostyelium septentrionalis Cavender.(2) Applying the organic fertilizer is the most advantageous to the Distyostelids survival, the quantity of the Dictyostelids is liwer than applying the organic fertilizer but higher than applying inorganic compound in the situation of applying ganic inorganic mixes fertilizer, the sole inorganic compound fertilizer applyment is inadvantages to the Dictyostelidssurvival.(3) The reasonable use of N,P,K is advantageous to the survival of Dictyostelids. P and K element is very important to the growth of Dictyostelids, so we can apply more P and K to the soil.Applying more N fertilizer is also advantageous to the soil and the quantity of the Dictyostelids is to be more.but if we use to much more N fertilizer,the quantity will instead reduce.(4) The quantity of Dictyostelids increases initially but decrease gradually along with time in every particle size, moreover each particle size plats the similar role.That is to say the difference of particle size plays no significant function to the quantity of Dictyostelids.(5) the water content and the soil air space present positive relation to the quantity of Dictyostelids.Its quantity increase along with water content and the air space increasement in the soil, but the quantity of Dictyostelids will decrease if the water content and the air space increase to much,obviously much higher soil moisture content and excessive soil air space will suppress the growth of Dictyostelids。 (6)Inspecting the influence of Dictyostelids quantities to the soil bacterium quantities, the results show that the two elements are counter-related, but along with the time, bacterium's quantity basically maintains invariable. This is probably because the quantity of Dictyostelids and bacterium have already maintained one kind of balance by now.