The soil water retention curve (SWRC) is the basic parameter of soil hydraulics to study soil water movement and soil water balance, which is closely related to soil physical and chemical properties. But the parameters of model is difficult to estimate. In this study, black soil samples with different erosion intensity were collected in the black soil region of Northeast China, and soil moisture under 7 soil water suction, mechanical composition, organic matter and bulk density were measured. We used Rosetta model to estimate the parameters of Van Genuchten (VG) model and compared the estimated soil moisture with the measured soil moisture. And then the simulation accuracy of different soil physical and chemical indexes and the suitability of the method to the black soil in Northeast China were evaluated. The results showed that there had little effect for the residual water content (θ_r) and saturated water content (θ_s) between 4 or 6 soil properties index, but had large difference for the scale parameter (α) and shape parameter (n). When the 6 indexes were used, shape parameter n decreased with the increased of scale parameter α. The relationship between the shape parameters m and n of the VG model was further modified, which improved the accuracy of model fitting obviously. The results of the 6 indexes were better than the 4 indexes. But the estimated values were different from the measured values and the estimated values were larger than the measured, which means soil moisture estimation need to be corrected according to the estimated value of relatively large degree. The fitting precision of Rosetta model for lightly and moderately erosion black soil was higher, and the precision of severely erosion black soil was lower. The model was suitable for sand content less than 46%, the clay content more than 28% of black soil in Northeast China.

In order to promote the management of soil fertility and precision agriculture effectively, provide some guidance for the soil and water conservation. A sloping cropland (0.91 km²) located in Heshan farm in Heilongjiang Province was selected as the research area,101 samples were collected by vertical and horizontal 100 m interval, for the study of spatial distribution of soil organic matter of the 0-15 cm top layer soil and the relation with soil erosion by the GIS and geostatistics math methods. The results showed that the average content of soil organic matter in typical black soil area was 4.13%, higher than the average level of Heilongjiang Province, and the proportion of organic matter content concentrated in the 3%-5%. Spatial variability of organic matter significantly which was mainly affected by soil erosion. High erosion area corresponds to low organic matter, erosion area in the corresponding medium organic matter content areas and sedimentary areas correspond to areas with high organic matter content. When the slope planted with an average gradient of 2.2°, per 1 000 t/km² soil erosion increased, accompanied with the content of organic matter will be reduced by 0.8%. The spatial variability of organic matter could be described by the spherical model, showed significantly spatial autocorrelation, further suggested that soil erosion causes the redistribution of soil organic matter. When the sampling interval is 200 m which based on the range, the interpolation of spatial distribution can accurately reflect spatial variability of organic matter content, to provide precision fertilizer sampling basis.

Emamectin benzoate is one of the most efficiently semi-synthetic antibiotic pesticides. However, little is known about the responses of composition, structure and biodiversity of soil animal community to the application of emamectin benzoate. In order to reveal the effects of emamectin benzoate on soil animal community, a field experiment was carried out in a typical black soil farmland area of Hulan district, Harbin city, Northeast China. Based on fixing-plot investigation in 2012, the plots were treated by different concentrations of emamectin benzoate, and then the soil samples were collected from different stratification (i.e. 0-5 cm, 5-10 cm, 10-15 cm and 15-20 cm) in May, July and September. In total, 5772 individuals belonging to 4 classes, 11 orders were captured, and all of them were divided into 31 groups. The results showed that under emamectin benzoate treatment (1) individual densities and group numbers of soil animal decreased significantly, and the decreasing trends of individual densities and group numbers were more obviously with increasing concentrations of emamectin benzoate; (2) the vertical distribution structures of soil animal communities were changed obviously, and most individuals and groups of soil animals preferred to gather in the 5-15 cm soil layer rather than in the 0-5 cm soil layer; (3) the diversities of soil animal communities were changed, but the contributions of different groups to community diversity were different, in which contributions of soil mites and springtails were relatively large than those of other groups; (4) the soil chemical properties of topsoil were changed significantly. However, responses of soil animal groups to soil environmental change were groups-specific, in which soil mites and springtails exhibited a stronger adaptive ability than those of the others. In a word, emamectin benzoate treatment can significantly change the community structure, vertical pattern and diversity of soil animal community in a typical black soil farmland area. It is emphasized that the concentration of emamectin benzoate might be an important indicator when we assess the influence of emamectin benzoate on soil animal community. It is suggested that we should prudently assess the ecological consequences when using the emamectin benzoate in farmland ecosystems.

Soil moisture is an important impact factor of agricultural production and regional ecosystem. The No. 2 small watershed in Heshan farm of Heilongjiang Province was selected as the study area, the characteristics of the dynamic of soil moisture and soil water profile in different land use types were analyzed in this article. The results showed that: the soil moisture of embankment was the maximal, and the woodland’s was the least. The variation trends of soil moisture content of different land use types were as same as the variation trend of precipitation in the observation period, and they showed a reduced trend, but there were some differences between the soil moisture variation curves of different land use types, the soil moisture cures could be divided into three types: two peaks and three troughs type (wheat field, soybean field, woodland and field road), two peaks and two troughs type (embankment), two peaks and one trough type (grassland). The soil moisture variation in the observation period was divided into relatively stable period, consumption period, and supply period. The influence of land use type on the water content of soil profile increased with soil depth, and the soil moisture of different land use types showed different variation trends with soil depth. Among them, because of the presence of plow pan, the soil moisture of wheat field and soybean field increased first and then decreased; the soil moisture of woodland decreased gradually with the soil depth; the soil moisture of grassland and field road for the difference soil property reason presented the trend of increased first and then decreased, but the max soil moistures of these two land types appeared in different depth; because of the soil property did not change with soil depth, the soil moisture of embankment increased gradually with the soil depth. In addition, there is also a seasonal diversity in the water content change of soil profile in every land use type. The water content variation of soil profile in wheat field appeared an obvious seasonal diversity, but with the increase of soil depth the diversity decreased; the seasonal change of soil moisture in soybean mainly in the depth of 0-70 cm, and the seasonal change was not obvious under the depth of 70 cm; the seasonal diversity of soil moisture change in each section of soil profile in woodland is the largest; the top layer and the layer in the depth of 70-80 cm which was composed by peat were the layers that seasonal diversity of soil moisture in grassland mainly happened, and the diversities of other layers were small; because of there were not any plants on the field road, and the soil moisture variation subjected only to the influences of rainfall and evaporation, the seasonal diversity of soil moisture in field road mainly appeared in the top layer of soil, but the diversity in deeper layer were not obvious; the seasonal diversity of soil moisture in embankment was as same as field road, but the reasons that leaded this phenomenon were that the soil property were all the same from top to bottom, and the soil moisture of top layer was effected by the plants, precipitation and evaporation. Besides the land use types, slope position and direction, soil texture, topography are all the important influence factors for the dynamic changes of soil moisture, further studies are needed to determine the interaction of these factors above and the main control factors.

Soil Loss Tolerance (T) is a quantitative criterion for soil conservation, and it is determined empirically at present due to limited quantitative researches. The black soil region of Northeast China, one of the major grain production bases in China, was selected as the study area. Soil depths were investigated and physicochemical properties of soil profiles were analyzed for 21 black soil species in the study area. T values of the 21 black soil species, calculated by using a modified productivity index model, varied from 68 t/km²×a to 358 t/km²×a, and 141 t/km² × a in average, and 106 t/km² × a for albic black soils (Albic Stagni-Udic Isohumosols), 129 t/km² × a for black soils (Hapli-Udic Isohumosols), and 184 t/km² × a for meadow black soils (Mottlic Hapli-Udic Isohumosols). Soil depths and soil erosion vulnerability index were two key factors influencing T values. The correlation coefficients of these two factors with T were 0.750 and 0.605 repectively. The meadow black soils had the largest soil depth and similar erosion vulnerability index close to that of black soils, and its T value was 42.6% larger than that of black soils. The soil depth of Albic black soils was 22.1% larger than that of black soils, and its T value was 21.7% smaller than that of black soils. This is due to the existence of obstacle horizon for Albic black soils. Therefore, determination of T values for different soil species or families is more practical for soil conservation in terms of soil profile properties.

The Songnen Plain in Northeast China is an important base of cash grain and soybean in China. Nonpoint source nutrient loads (TN, TP, NH₃-N, NO₃^--N, PO₄^3--P) to the water bodies were estimated using ¹³⁷Cs nuclear tracing technique and field monitoring method. The annual mean erosion thickness of black soil in the typical slops is within 0.120-0.525 cm, and the erosion intensity is 1355.0-7558.2 t/km² in last 40 years. The annual mean values of pollution loads per square kilometer were TN 1.43 t, NH₃-N 15.01 t, NO₃^--N 8.51 t, TP 0.42 t, PO₄^3--P1.85 t, respectively. Water dissolved inorganic nitrogen and phosphorus accounted for 0.51% of total nitrogen, and 0.12% of total phosphorus. Caesium-137trating technique is an differentive to traditional methods.

选取吉林省大黑山东西坡台地农田系统的12组土壤样品，采用常规分析的方法对土壤有机质、全N、速效N、全P、速效P和速效K进行测试。利用独立样本T检验和相关分析的方法对数据进行单因子和多因子的综合分析，探讨成土母质、水、热条件等因素对黑土养分变化的影响。结果表明：大黑山东西两侧台地上黑土养分差异明显，西坡较东坡黑土肥力高，东坡比西坡黑土退化严重。产生这种差异的原因与地形差异和人类干扰关联不大，主要和东西坡两侧的成土母质、地方气候的异质性相关。这一结论对从地方尺度研究交错带这一特殊区域黑土退化的本质有一定的指导意义，为更合理地利用黑土资源提供理论依据。

Soil on slopes of the gentle hilly black soil region in Northeast China, one of the most important bases of cash rice, degraded seriously after dozens of years of intensive cultivation. The thickness of soil humus layer becomes thinner and less fertile year after year. So it is very essential to deepen the researches of soil restoration and improvement after severe soil erosion. Analysis of main reasons for black soil degradation revealed that the cultivation activities halted the accumulation of organic matter and then baffled the soil development which cannot compensate the decrease of the thickness of soil humus layer caused by soil erosion. Soil developing process and conditions are the most important foundation for soil restoration. So the developing history of black soil and chernozem was reconstructed and the geomorphological and climatic factors, which were the key factors affecting the formation of black soil, were analyzed through studying both the formation time of the underlying strata and the local climate change history since the late Pleistocene. The conclusion is that black soil and chernozem formed in different periods, from early period of late Pleistocene and the beginning of Holocene respectively. The former period was warm and wet, while the latter period was warm and dry. And they formed in different places, the black soil was mainly distributed on the second and the third terraces and the chernozem on the first terrace of the Nenjiang River, which is lower than the distributing places of black soil and can accept more carbonate from the highland to form the characteristic illuvial layer. The processes of the soil formation were very slow, so it is hard to restore. These results provide important basis for forulating policies to improve the quality of soils in the region.

Soil erosion in black soil region in Northeast China leads to soil redistribution on a slope and great spatial variance in the thickness of soil humus layer. Changes of humus layer thickness will result in such physical properties variations as soil moisture and soil temperature. And soil moisture and soil temperature are important factors for freeze-thaw erosion, besides they can affect soil particles and chemical elements movement on the surface and soil profile. In order to explore the law of changes of soil moisture and soil temperature by time and depth of soil profile, two field monitoring points A and B were selected to monitor soil moisture and soil temperature simultaneously. At site A, soil humus layer is about 60 cm, and at site B, soil humus layer is about 130 cm. Soil temperature was recorded with a thermistor thermometer at eight o'clock a. m. everyday from 10 April to 14 June and twice a week from 23 January to 7 April. Soil moisture was monitored with an oven after sampling by drills. Soil moisture and temperature were measured at an interval of 10 cm from the surface to 150 cm deep on two profiles in the paper. Results show that the thickness of humus layer has significant influences on soil moisture and soil temperature. The thicker the humus layer is, the slower the rate of thaw. At site A, the rate of thaw was 2.4cm/day, however, it was 2.1cm/day at site B. Furthermore, the freeze time lags a week or so. At the same time, soil moisture of thicker humus layers is more than that of thinner humus layers in black soil region, as well as the moving extent of soil moisture is deeper. The humus layer has a great impact on the distribution of soil moisture on the profile. As a result, runoff rate during a rainstorm will occur differently from place to place because of the diversity in humus layer depth on a slope.

Black soils in Northeast China is main agricultural resources for grain production in China. The sustainability of agriculture in Northeast China is jeopardized by soil erosion and degradation of soil fertility. This article took the black soil as a target to analyze its erosion types and characteristics. Surface erosion by water is the most dominant erosion process for the majority of black soils in the region. Many eroded soil materials associated with the runoff have been re-deposited in low-lying land. Reasonable agronomic management practices can conserve black soils from erosion and regain black soil fertility, including contour ploughing and conservation tillage.

Based on the average daily wind speed data, average daily air temperature data, daily precipitation data of 1951-2000, and the daily dust data of 1980-2000, the wind erosion environment of black soil region in the northeastern China was analyzed. In the study area, the average air temperature from January to May has been increased markedly since 1951. And the total precipitation from January to May has no obvious change. In Nenjiang annual gale days in 1980-2000 was much more than that in 1950-1960, annual dust days have increased too, so the soil wind reosion environment in Nenjiang is serious than before. In Harbin and other stations in the study area soil wind erosion environment is weakening. In the whole northeastern China, the soil wind erosion environment is moderate.

In this paper the conceptions of the black soil and the black soil reg ion have been clarified.We have zoned the black soil area into the typical black soil region and the black soil region in China.The three black soil regions in the world have been compared in terms of the soil,forming condition,the process of exploitation and utilization,and the soil erosion and the soil and water cons ervation.Although there are some similarities in natural conditions in the three black soil regions,the black soil in China is prone to be eroded for its undula ting relief.The large,scale land reclamation and the unreasonable farming practi ces are the prime reasons to cause soil erosion and the soil degradation in the three black soil regions.Most of soil erosion taking place in the black soil reg ion of China is water erosion,but the wind erosion dominates in the other black soil regions in the world.Comparing with the other black soil regions in the wor ld,the black soil region in China is still lagging behind in some aspects in soi l and water conservation,such as cropping system, land use policy,funds invested ,propaganda and education and scientific experiment in soil erosion control.The disadvantages in the control of soil erosion and water loss in China's black soi l region are identified through comparing with soil and water conservation measu res conducted in the other black soil regions in the world.Problems that have to be settled urgently in soil erosion control in the black soil region of China a re proposed.

Black soils are main agricultural soils in Northeast China and the organic matter content of these soils has been one of the hot research topics for many years. By referencing the data and sampling locations in the Second National Soil Surveys of Jilin Province conducted in the 1980s, we re-sampled 27 black soils along the Jing-Ha (Beijing-Harbin) railway in central Jilin. The contents of soil organic matter and total nitrogen of those soils were determined and compared in pair with the data measured 20 years ago on an equivalent depth. We found that 2-decades intensive farming affected differently the contents of soil organic matter and total nitrogen, with increasing for some soils and decreasing for others. However, there was no significant difference in overall average of soil organic matter. By comparing the results with other studies, we believe that the present corn dominated production has balanced soil organic matter level of black soils through roots alone in areas where soil erosion was not a problem. However, the soils that organic matter decreased during the past two decades might be subject to severe soil erosion. During the same time, some black soils gained organic matter.

Researches of ¹⁴C dating,pollens analysis, historical documents and archaeological investigations prove that the climate of the Xiliao River valley came into the warm period in the first half of the Liao Dynasty.In this period of time, not only the blackland developed, which provided the conditions of agricultural development, but also the ecological environment composed of plants, animals,lakes and rivers in this valley was in positive stage, which provided the base for the rise of the Liao Dynasty. The site of Xiliao River valley determined the characteristics of physical geography of the region and the its climate change could not exceed the limit of its natural zone.Slices of deserts were also distributed over the background of typical steppe in Xiliao River valley.Phenomena of windblown sand were often happened.

The spatial variation law of soil organic carbon(SOC) and the content variation of SOC in different tillage periods in typical black soil distribution area of China were studied. The results show that, with the increase of latitude, the average total black soil organic carbon content increases from 11.43 g/kg to 20.83 g/kg, the organic carbon compositions content and HA/FA ratio show a increased trend. With soil profile depth increased, the black soil total organic carbon and HA-C, FA-C, HU-C contents are decreased, the black soil total organic carbon contents in A, AB and C layers are 16.04-40.28 g/kg, 8.04-13.82 g/kg, 4.84-9.13 g/kg, respectively. The ratio changes of FA-C/SOC, HA-C/SOC and HU-C/SOC are different in soil profiles from A to B layer, the ratio of HA-C/SOC is to reduce gradually with soil profile depth increased, and the ratios of FA-C/SOC and HU-C/SOC are to increase gradually with soil profile depth increased, HA-C is substituted for FA-C and HU-C gradually. It is shown that ability of humus wholly decayed is to reduce with soil profile depth change. Black soil total organic carbon and its compositions content decrease rapidly before 50 years tillage, then decrease slowly. After 130 years tillage, the soil organic carbon content is relative stable basically.

Black soilsare the most fertile ones in China,but they are suffering from deterioration, which includes water loss and soil erosion. The landform of black soils is undulated peneplain so that the soil is easy to be eroded. In this paper, the authors propose three antierosion measures: 1)Slope erosion prevention includes two parts, the first part is changing the aspect of the ridges of the land from slanting or parallel to vertical to horizontal direction, if the slope is less than 4 degrees; the second part is that if the slope is bigger than 4 degrees, the terrace should be made to avoid erosion. 2)Gully control includes building gully head embankment or dyke or even small reservoir, planting trees and grasses in the middle part; ducks, gooses, fishes and frogs could be raised in the pools or reservoirs to increase the economic efficiency. 3)Planting trees to make forest prevent wind and erosion. The authors also suggest that the management should be improved, the present situation is that there are laws in China protecting the crop land, but the laws can only protect the crop land quantatively.To guarantee the quality of the crop land, thorough study should be made, and the monitoring organization should be established.