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贛中丘陵地区红壤性水稻土分布面积很广,但由于所处的地形部位不同及人类耕作措施各异,各类红壤性水稻土的肥力水平有很大差异。影响土壤肥力水平有两个方面:卽土壤既能滿足作物生长过程所需的水分和养分,又能使作物有良好的“居住环境”,而土壤的物理性质对保証作物良好的居住环境起有决定的作用。研究土壤的结构、各结构体内的孔隙状况以及結构胶結物貭的种类和数量,对认識土壤物理性貭在提高肥力上的作用具有很大意义。根据我們初步的研究結果,紅壤性水稻土中,水稳性結构大于1毫米粒級的結构体,含量較少,一般仅占总数的7—18%,小于1毫米的占80%以上。在小于1毫米的各粒級中,除<0.25毫米粒級占絕对优势外,1—0.5毫米的粒級占7—32%,肥土(烏泥田)中1—0.5毫米粒級的含量較高。不同土壤的結构体,由于其内部的孔隙状况不一,土壤肥沃度也各有异。肥土結构体内的总孔隙度高达43%,而瘠土(結板田)只26%。如按相同粒級結构体内的孔隙相比也是肥土中高而瘠土中低。在这个地区土壤結构体内孔隙的形成,主要取决于結构胶結物貭的种类和数量以及微凝聚体的排列形式。一般的說,如果胶結物貭以无定形R_2O_3或多量粘粒的接触作用为主,則結构体內部的孔隙度較小(如紅瓖母貭)。肥沃的紅壤性水稻土中,結构体的胶結物貭以有机貭起主导作用及顆粒大小不均一,使結构体內部的孔隙度較大。由于胶結物貭的种类和数量不一,有机、无机胶体的复合类型也不同,因而使肥土中的結构体不仅具有水稳性,而且还是多孔性的。只有这种結构体才能調节和滿足作物生长所需的土壤环境,才能形成肥沃的土壤。
The distribution area of reddish paddy soil in hilly areas in central Jiangxi Province is very wide. However, due to the different topographical positions and different tillage practices, the fertility levels of reddish paddy soils vary widely. Soil fertility levels affect two aspects: 卽 soil can not only meet the water and nutrients needed for crop growth process, but also make crops have a good “living environment”, and the physical properties of soil to ensure a good living environment for crops The role of decision. Studying the structure of soil, the state of pores in each structure, and the type and amount of structural cementing material are of great significance for understanding the role of soil physical properties in improving fertility. According to our preliminary results, the structure of water-stable structure is more than 1 mm in red paddy soil, with less content, accounting for only 7-18% of the total and less than 1 mm accounting for more than 80%. In each particle size of less than 1 mm, particle fractions of 1 to 0.5 mm accounted for 7-32%, particle fractions of 1 to 0.5 mm in fat soil (Undaria pinata) Higher. Different soil structure, due to the internal porosity of different conditions, soil fertility are also different. The total porosity in the body of fat soil is as high as 43%, while in the barren soil (knotted field) it is only 26%. If the pore structure of the same size structure is also compared to the high soil and low soil fertility. The formation of pores in the soil structure in this area depends mainly on the type and amount of structural cement 貭 and the arrangement of microaggregates. In general, if the cementitious material is dominated by the contact of amorphous R_2O_3 or a large amount of clay, the internal porosity of the structure is small (eg, red mulberry). In the fertile red paddy soil, the cementitious material of the structure plays a leading role in organic structure and the particle size is not uniform, so that the internal porosity of the structure is larger. Due to the different types and amounts of cements, the composite types of organic and inorganic colloids are also different, so that the structure in the soil is not only water stable, but also porous. Only such a structure can regulate and meet the soil environment needed for crop growth, in order to form a fertile soil.