摘要
一、潜育性和次生潜育化水稻土的形成和类型 (一)问题的提出 (二)潜育性水稻土的形成 (三)潜育性水稻土的类型 二、潜育性水稻土的性质 (一)潜育性水稻土的物理性质 (二)潜育性水稻土的化学性质 (三)潜育性水稻土的养分特性 (四)
<Abstracy>This study was done from 1979 to 1984.Main results of the study are su-mmarized as follows:I.The formation of gleization of paddy soil Factors inducing soil gleization are rather complicated.The main cause is poor permeabilith,especially in the plowpan layet where its poroisty is low.The level of ground-water,distance of rice field to the irrigation ditch, the occurrence of sandy and clay horizon in the soil profile also affect the permeability of soil.Soil gleization is also affected by the environmental conditions.The first one is poor drainage,expecially under irrigation.The second is improper cul-tivation system such as the adoption of doudle cropping rice,which may pro-long waterlogging period. The third is shallow ploughing,which may thicken the plowpan.under the conditions mention above,secondary gleization may take place readily on most paddy soils with poor permeability. Ⅱ.Types of gleying paddy soils According to redox status,expecia-lly the position of gleying horizon and structure of soil profile,we divided the gleization of paddy soin into six types:1.Snrface layer gleying.The fea-ture paddy soil profile is ag p b bc or ag pg b bc;2 plowpan gleying.this is the main type of secondary gleization of paddy soil. the feature of soil profile a pg b c(g);3 interlayer gleying. there is anon-permeable stratum between the surface layer and subsoil .the feature of soil profile is a pg b g or ag pg w g;4 upper part aleying. the glcying layer appears below plow layer or plowpan.the feature of soil profile is a p g;5.whole profile (or swanpy)gleying .the feature of soil profile is ag g or ag g ;6.lower part gleying .gleying layer below surface 50 cm.the feature of soil profile is a p b g. the chearacteristics of gleying paddy soil the gleying paddy soils,especially he gleying layer are almost waterlogg ing .the permeability of soil is very poor.it is under strongly reducing con dition,even in the season under upland crop,the redox porential is below 200 mv,all of thexe factors are rearding the growth of crops,the characte ristics of gleying paddy soil are desc ribed ax follows:1.the physical characteristics:almost the clay conthnt of the gleying layer is higher than others,the ratio of lower than normal paddy soil.the permeability of gleying soil is very poor.the soil pore spacealways fill with water and low soil temperalure in spring. the chemical characteristics;the redox potential of gleying paddy soil is lower than normal paddy soil.the accumulation and the content of redu cing matter of gleying layer or soils are higher than othersl.the ration of c/nis hgher .the normal paddy soil for example,the ration of c/nin a strong gleying paddy soil is aboutll-but inthe normal paaddy soil is about the conthent the horizon on its top is low but the ration of active iron to total iron is high in comparison with others .asa result of gleization,the percentage of reduced iron is high,ferrous iron may amount to 5 of the total iron content.the conthntthe nutrients supplying capacity of gleying paddy soil:due to the miner alization of ncontained organic matter in gleyed paddy soil is lower than nor mal paddy soil the nsupplyin glayeing soil is low .for example the quantity and ratio of nmineralzatoion ia micro plot experiments using nlabelled rice straw were shown.when early rice of the total nassimilated by rice derive from labelled rice straw,but on the gley when early rice planting on a normal paddy soil there is the total assimilated nof rice derive from soil and on a strong of total nderive from soil and from nfertiliaers.the amelioration of gleying paddy soil there are four amelioratiue practice of gleying paddy soil may be used;apply fertlizer rationally to in reease in crops yield .due to deffici cncy of available nutrients in gleyed paddy soil,according to the content of available nutrients in soil and requirement of crop to apply fertilizer may be increase in crop yield.apply comprehensive practice to mprove gleyed paddy soil .better drai nage,proper rotation of rice and upland crops,improvement of cultiv ation
出处
《农业现代化研究》
1984年第6期5-25,共21页
Research of Agricultural Modernization
