Abstract:China has got great achievements in agriculture, and the aspects to play a very important role in promoting agricultural production include the advancement of soil and fertilizer science, the transformation from the scientific and technological achievements to the productive forces, and the foster and imporvement of soil fertility, rational exploitation and use of soil resources, and the plant nutrition and fertili.zer application, etc. This article paying a particular attention to the domain of extension of soil and fertilizer science and technology is devided into two parts. One part is the present situation and achievements of soil and fertilizer work in China, looking back over the soil and fertilizer work in the past time, which deals with the basic soil and fertilizer work and science and technology extension. The another part is the tasks of soil and fertilizer work, looking forword to the future prospect and going further into the principal tasks anu measures for science and technology extension during period from the Eighth Fiveyear plan to the end of this century.

Abstract:On the basis of the properties of red soils and the features of acid rain the characteristics of sensitivity of red soils to acid rain in South China are dealt in the present article. An acid-buffer curve method is put forward for studying the sensitivity of red soils to acid rain. In terms of soil acid-buffer curves two indices, i.e, soil acid-damage capacity and soil acid-sensitivity value (△pH s.v.), are proposed. According, to a lot of results of acid-buffer curves the primary classes of both indices and the reconnaissance division map of soil acid-sensitivity in Guangdong, Guangxi and Hainan have been made.

Abstract:By the use of cluster analysis, the micro-elements of the vegetation can be sorted into 4 categories and the microelements into 3 categories. Based on the accumulated state of macro or micro-elements, the vegetation can be divided into 4 or 6 types. The chemical composition in vegetation is not directly related to the chemical composition of soils, but is closely related to the soil types and soil geochemical types. The vegetation on desert soils and saline soils belongs to Na-enriching categories, whereas Si-enriching vegetation is mostly distributed on Chestnut soils and Brown talc soils. For microelements, the ratio (Mn+V+Co+Ni+Ba+Cu)/(Sr+B+Zn+Li) is more than 1 on Brown talc soils, Chestnut soils and mountainous soils but less than 1 on flat soils; as regard of the ratio(K₂O+Na₂O)/(Cao+MgO), it is more than 1 on saline soils, but less than 1 on Siallisols and Carbonate soils, of which reaches minimum value on Carbonate soils. As for the ratio K₂O+Na₂O, it gets maximum value on Siallisols.

Abstract:There are several Paleosols which contain a high proportion of clay with the leaching out of lime carbonates in loss profile. The origins of the clays have caused great argument. Researchers who maintain the point of view of residual argillification have thought that the clays in the paleosols are dominated by illites with Iime-magnesia saturation and have very weak hydrophility and mechanical eluviation. But, the phenomena of clay partial translocation and accumulation do exist in either recent soils or paleosols. For instance, the shining cutan outside the ped or optical orientation clay particles and whorl-shaped aggregates in the thin section investigations or both of them were observed. This paper, besides the affirmation to the existence of above phenomena, indiGates that the causes of the phenomena are different from those of phenimena which result from the mechanical eluviation and illuviation in common soil profile in that they were caused by intensive biological effect, espectially by bio decay and minerslization and mineral feedback and "biosynthesis" (biogenetic) of the clay minerals in two to one crystalline structure on the surface of mollisols in which herbage had grown lushly at the early stage of the soil formation, and "mitcro-ice wedge like" actions particually the later even leads to the formation of star-clove of garlic-shaped soil masses with smooth and shining surface within the transitional areas between claying hirizons and C horizons.

Abstract:The eluviation-illuviation and movement regular patterns of different forms of iron and manganese in the acid sulfate soils were studied. The various iron and manganese oxides in the soils were in an inter connected and interactive eqlibrium systrm and an aging and activating contradictory entity. The soil acidity controlled the transformation of different forms of iron and mandanese. The acid sulfate soils had a special regular pattern of iron and manganese transformation, since they are very acid and contain a more O.M. Form the surface layer to the ground layer of the soil profiles, the pH value became lower, the ratio of amorphous iron/free iron became bigger and the ratio of crystalline iron/amorphous iron becamr smaller, along with the development of the soil profiles. As compared with iron, manganese was more sensitive to the change of redoxing condition, and the contents of total and easily reducible manganese were rather low in the acid sulfate soils.

Abstract:For the understanding of the distribution of Vertisols and vertic soils in Yunnan-Guangxi region of China and better use of the soils, seven profiles were collected for the study of genetic properties and taxonomic classification. The results showed that the weathering process of Vertisols was much weaker than that of zonal soils. The element hyper-geochemical features also showed the same regularity because of the lower degrees of relative enrichment of Al, Fe and Mn and leaching of K,Mg, Ca and Na in Vertisols. On account of the montmorillonites being over 35% of the clay minerals and a special microstructure, Vertisols had a very high swell-shrink potential with the swell-shrink value and COLE being 40% and 0.09 respectively. Meanwhile, high swell-shrink potential leads to the formation of unique micromorphology features, such as voids being mainly fissures, hairline cracks and plasma separations including asepic, insepic, masepic, lattisepic, vosepic and skelsepic. The results obtained showed that profiles belong to Vertisols, Ferrasols and Anthropic Soils, respectively, according to the Chinese Soil Tixonomic Classification, and some profiles of the latter two soil orders maybe fall into the vertic subgroup. Some delimiting standards of orders, suborders and great groups of Vertisol and vertic soils are suggested.

Abstract:According to the Chinese Soil Taxonomic Classification (1st proposal), the author in this paper classifies 14 soil profiles in the island region of Zhejiang Provence, and the soils are considered to belong to the brown-red soils and para-red soils. Owing to very high base-saturation percentages of the soils, the soils are further divided into eutrophic brown-red soil subgroups. Since there is no corresponding subgroup in the para-red soils, the reestablishment of eutriphic para-red soil subgroups is recommended.

Abstract:Alfisols are important soils in China. They occupy about 1.25 million km² or about 13% of the land area. Dark brown forest soils, burozems, yellow-brown earths, and drab soils in temperate China are identified as four major great soil groups. According to the criteria given by soil Taxonomy, these soils should belong to Alfisols. Additionally, Baijiang soil is identified as a special kind of Alfisols, probably Albaqualfs. These are mostly forested soils with a return of organic matter, estimated at 5-13t/ha/yr, to the soils from a mixed temperate forest. In terms of elemental bio-cycling Ca is prominent.In a comparison of 30 profiles, the average rate of clay (B/A) was 1.47 for cryoboralfs and Eutroboralfs: 1.88 for Hapludalfs and 2.53 for Paleudalfs. From Eutroboralfs to Paleudalfs there was a difference of 7 times in the average gain (or loss) in clay during soil development. Hapludalfs, Cryoboralf and associated Cryaquepts differ considerably in the moisture regimes, but the amount of water is always enough to cause a significant leaching. During the weathering and pedogenetic processes-TiO₂, Mgo and Fe₂O₃ are accumulated, respectively, in both A and Bt horizons; But SiO₂ and Al₂O₃, tend to be leached from the solum.

Abstract:In the Huang-Huai-Hai pla in, the "desalinized fertile layers" could be established in salt-affected soils within 3-5 years by application of stalks or excrements of livestocks fed with stalks, and the crop yield up to 12690 kg/ha could be got on salt-affected waste lands. The soil salt content should be decreased to below lg/kg in 0-20cm and below 2g/kg in 20-40cm in "desalinized layer" (0-40cm). The minimum and maxinmum soil organic matter content should be l0g/kg and 15g/kg, respectively, in 0-20cm soil layer which may be called "fertile layer". The abilities of adjusting and controling soil salts were strenthened by increasing bioactivity activating nutrients and improving kinetic parameters in the soils.

Abstract:Under an atmosphere containing 97% Ar and 3% CO₂ or containing 100% Ar, the nitrogenase activity of Anabaena 7120 was much higher or lower, respectively, than that in air. When the treatment was done in the above listed atmosphere considerable variation in the NH₄⁺-derepression of nitrogen fixation in Anabaena occurred. Moreover, the response of NH₄⁺-derepression of nitrogen fixation in Anobaena to physiological conditions differed. When algae was incubated in O₂ or N₂, Respectively, the extent of inhibition of NH₄⁺-derepression in Anobaena with a lower nitrogen-fixing activity was greater than that in one with a higher activity. A great acceleration of NH₄⁺-derepression of nitrogen fixation by hydrogen in Anabaena with a higher nitrogen-fixing activity was observed. The rate of NH₄⁺-derepr;.ssion of nitrogen fixation in Anabaena with a higher nitrogen-fixing activity was significantly faster when the hydrogen was added with oxygen or added only with exogenous carbonhydrates, such as sucrose or pyruvate, to the test system. Under weak light or in the presence of phtosynthetic inhibitors in the reaction system, the NH₄⁺-derepression of nitrogen fixation was more pronounced in Anabaena with a lower nitrogen-fixing activity.

Abstract:This paper deals with the potassium and K-bearing minerals in the soils in South of China. Results show that the contents and types of soil K-bearing minerals were influenced by parent materials and soil development, the K-bearing minerals in the soils developed from granite increased with the particle size (with the exception of >50μ fractions), but a contrary result was found for the soil derived from sediment rock. Soil nonexchangeable was well correlated with the contents of micaceous minerals (r=0.669), and exchangeable K was significantly correlated with soil CEC(r=0.808^**). Different particle size fractions made different contribution to the total potassium in the soil. Total potassium was mainly concentrated in the fractions of 10-50μ and >50μ for the soils derived from granite, and in the fractions of <2μ and 2-10μ for those derived from sediment rock.

Abstract:The suitable groundwater level and soil water indexes for wheat are mainly discussed in this article, the groundwater level index was studied by the combined dynamic and static water level method, while the energy indexes of both waterlogging and drought-enduring soil water were got using the technique of soil water energy measurement. The suitable groundwater depth for wheat was 0.8 meter during the whole growing season; if it's drought during plantin;, the depth shoued be raised to 0.5 meter for the full emergence of seedlings; during the period of after tilling to the end of feberuary the depth should be cut down to 0.8 meter progressively; and during the middle and later growing periods of wheat (March-May), the depth should be controled at 0.8 meter 3-4 days after rainfuli. During the midelie and later growing pericds of wheat, the waterlogging enduring soil water index was the water suction of >3kPa in the 40cm soil horizon; and the droughtenduring soil water index was the suction of ≤ 100kPa in the 40cm soil horizon at booting-heading and flowering stages. The aeration porosities for creating a good aeration status of soils could be 8-15% in plowed layer ≥ 4% in plow sole, and ≥5% in B-horizon. In the heavy loam soil area of Kunshan, the pipe drainage with a pipe depth of 15 meter and a distance of 15 meters could meet the needs of all indexes mentioned above.

Abstract:利用蔗渣栽培香菇,有显著经济效益,由于,每年产生种菇废菌棒的数量很大,因此可利用废菌棒作基肥,能明显促进甘蔗生长。蔗渣种香菇,取得菇业促蔗业发展的同时,废菌棒回田可作甘蔗良好的有机肥。这样将蔗渣多级利用,不但变废为利,保护环境,又从另一个方面促进蔗业的增产增收。本文通过上述栽培措施对甘蔗生长作用机理的研究,以明在推广应用方面提供试验依据。

Abstract:晋西北黄土丘陵区位于黄河中游、黄土高原北部的晋、陕、内蒙三角区内,为黄河的主要产沙区,以水土流失严重著称,是一个迫切需要治理的地区。“七五”期间,黄土高原综合治理(国家科技攻关项目),在该地区的砖窑沟流域设置了综合治理试验示范区。从1986年起以田间试验与定位观测相结合,已历时6年,比较系统地研究了试验区的土壤改良措施和培肥途径。