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In order to explore the suitable technology for the reclamation of erosion gullies in the black soil area of the Northeast China. In this paper, Xinhua farm is selected as the research area which is located in Hegang City, Heilongjiang Province, China. Aiming at the cause of erosion gullies, a new technology of filling and reclamation erosion gully with coal gangue was introduced and the post effect of the new technology was studied, including, the technological process of filling and reclamation, the influence of the thickness change of reclamation filling materials on the drainage characteristics of the gully, the fertility status and heavy metals pollution degree in the reclaimed soil. This paper aimed to explore the feasibility and breakthrough points of the technology of filling erosion gullies with coal gangue. The results showed that: 1) The increase in soil layer thickness could weaken the drainage capacity of the gully, while the increase of mixed size coal gangue thickness and large size coal gangue could increase the drainage capacity of the gully in different degrees. The interaction between the soil layer thickness and large size coal gangue layer thickness obviously influenced the drainage capacity of the gully. When the thickness of soil layer, mixed size coal gangue layer and large size coal gangue layer were 53.42, 38.51, 90 cm respectively, the shortest outflow time was 145.129 s, the drainage capacity of simulated 2 m deep gully was the strongest in this mode. 2) After 4 years of gully reclamation, the soil bulk increased, the soil acidity improved, the content of total potassium was the same as CK, but the total nitrogen, total phosphorus and organic matter content were lower than CK. And then the comprehensive fertility of soil was less than CK, which is 66.71%-80.81% of CK, and the average level only reach to 72.75%. But it was slightly higher than that of the second accumulated temperature zone in Heilongjiang Province. 3) The content of Pb was basically the same as CK and background value of local control soil; however, as for Cr and Cu, they were higher than CK and background value of local control soil in the reclaimed soil of monitoring gully. But the content of Cr, Pb, Cu are not higher than the second level standard value of national environmental quality of China. . There are slight pollution and slight enrichment of heavy metals Cr, Pb and Cu in monitored gully reclamation soil, so coal gangue can be used as a material for filling erosion gully for reclamation. However, in the long term, attention should be paid to the problem of soil heavy metal enrichment during reclamation. [ABSTRACT FROM AUTHOR]

The purpose of the study was to improve the pertinence and accuracy of salinization monitoring and control. The main data sources for this paper include agricultural land classification database, 1:500 000 spatial distribution data of saline-alkali land, China earth international exchange station climate data daily value sata set (V3.0), 1:1 000 000 soil database data, 1:1 000 000 spatial distribution data of soil texture in China, land change survey database and other data of Heilongjiang Province. With the support of the above data, on the one hand, research starts from the connotation of land salinization, filtered out land risk assessment factor from numerous factors, include landform, soil texture, evaporation and precipitation ratio, groundwater mineralization, regional sensitivity, land use level, the relationship between land salinization and its correlation was analyzed by the grey correlation model, and used the grey correlation model to analyze the correlation between these factors and land salinization, in order to verify the rationality of the selection of indicators, based on this, carry out grid training and accuracy test, formed land salinization assessment model. On the one hand, started from the extension of land salinization, screened out the resistance factors of soil salinization diffusion or migration, and constructed a resistance surface, used the minimal cumulative resistance model to evaluate the risk pattern of land salinization landscape. After the above work was completed, then with the help of ArcGIS spatial analysis function, superimposed the evaluation results of land salinization danger and land salinization landscape risk pattern, Formed land salinization type zones and monitoring levels. This paper takes Heilongjiang Province as an example to apply the method, the main research results were summarized as follows: 1) In terms of the salinity danger of the land, the land salinization danger of the salinity risk of severe and above land were mainly distributed in the southwestern part of the Songnen Plain, moderately distributed in the north-central part of the Songnen Plain and the northeastern part of the Sanjiang Plain. The light and below were mainly distributed in the great and small xing'an ridge and the southeastern mountainous areas. Eastern Songnen Plain and Southern Sanjiang Plain. 2) In terms of risk pattern, the severe and above were not only distributed in the central and northern parts of the Songnen Plain, but also in the central and northern parts of the Songnen Plain. In addition, there were also a small distribution in the northeastern and southeastern mountain areas of the Sanjiang Plain; moderately except in the Songnen Plain. The northern part and the northeastern part of the Sanjiang Plain were distributed, in the Middle and Central South of the Songnen Plain, the central and western parts of the Sanjiang Plain, and the southeastern mountain areas were also distributed; the mild and the following risk patterns were mainly distributed in the great and Small Xing’an Ridge, in addition to Sanjiang there is a small distribution on the southern edge of the plains and southeastern mountains. 3) The monitoring level of salinization in Heilongjiang Province showed the overall pattern of the west > east > central, northern and southern regions, the high-level and medium-level monitoring areas were mainly distributed in the western, southwestern, northern parts of the Songnen Plain, and the northeastern part of the Sanjiang Plain, the low-level monitoring areas were mainly distributed in the eastern part of the Songnen Plain, in the south of the Sanjiang Plain, and in the southeastern mountain areas, non-monitoring areas were mainly distributed in the large and Small Xing'an Mountains. The conclusion is that the land salinization monitoring area identification technology based on the risk and landscape ecological risk pattern takes into account the connotation of salinization and the extension of salinization, which provides scientific basis for the monitoring and prevention of land salinization. [ABSTRACT FROM AUTHOR]

Soil microorganisms participate in the energy flow and nutrient cycle of soil ecosystem, affecting the geochemical cycle process of organisms. Their diversity and community compositions play an important role in determining the function and sustainability of soil ecosystem. The functional diversity of soil microbial community is one of the important indexes to express the soil microbial community and ecological function. Soil microbial diversities of black farmland under different land use types are of great significance to the rational utilization and protection of soil resources. This paper explored the diversity of black soil microorganisms under different land use patterns of farmland, including maize, rice, soybean and potato, and taking the wasteland as the control. The Biolog Eco microplate method and pure culture of bacteria were used to study the changes of soil microbial diversity under four different land use patterns in the black soil area of central and southwest Heilongjiang province. The results showed that: 1) The number of culturable bacteria from more to less were potato, rice, soybean, maize, wasteland, but the variation of Shannon-Wiener diversity index from high to low was: wasteland (2.18), maize (2.11), potato (2.00), rice (1.73), soybean (1.49). 2) The utilization degree of carbon source of microorganisms in black soil under different utilization patterns increased with the extension of culture time. We found that amino acids, carbohydrates and polymers were main carbon sources for the metabolism of microorganisms in black soil. The Shannon-wiener index (3.18), McIntosh index (5.96), richness index (24.89) and Simpson index (0.95) of maize soil microorganisms were higher than those of other land use patterns, among which the diversity index of rice soil microorganisms was the smallest. There was no significant difference between the diversity index of potato, soybean and wasteland. Maize was better suited to the soil environment of farmland in the black soil area of Heilongjiang Province. 3) Principal component analysis identified two principal component factors that were related to carbon sources and explained 54.43% and 7.95% of the variance, respectively. Principal component analysis showed that different land use patterns significantly affects the metabolic diversity of carbon sources in the soil microbial community, and the main types of carbon sources that differentiated the metabolic characteristics of the soil microbial community were carbohydrates, amino acids and carboxylic acids, among which carbohydrates were particularly prominent. It showed that different land use patterns can affect the functional diversity of soil microorganisms. The results of this study is helpful to understand the relationship between soil microbial diversity and land use patterns of farmland in black soil area and provides certain scientific basis for agricultural development and scientific and rational utilization of black soil resources. [ABSTRACT FROM AUTHOR]

Technology of straw bale combustion is one of the effective ways to realize the clean utilization of agricultural residue, which has caused widespread concern. In this paper, the latest research progress of straw bale combustion was reviewed, the reaction principle and combustion characteristics of straw bale combustion were described, the generation and emission of particulate matter in the process of straw bale combustion were analyzed, such as NOx, CO and particle. And the research of straw bale combustion types, principles and characteristics were systematically summarized. Researchs showed that the combustion process of straw bale is mainly divided into two stages: volatile combustion and straw charcoal combustion. The heat released by volatile combustion accounted for more than 67% of the heat in the whole combustion process, which affected the combustion state of the whole straw bale.According to the technical characteristics and heating scale, we divided straw bale combustion into two types, one was continuous bale combustion, which can realize continuous feeding and ash cleaning in the combustion process, maintain a stable combustion state in the combustion chamber, and was suitable for the central heating area with large heating area, that mainly included cigar-bale combustion and reciprocating grate combustion. The other was batch combustion technology, which had advantages in small floor area, simple and convenient operation, usually used for small heating mechanism, and it included forward combustion technology and reverse combustion technology. Based on the global literature search, the research hotspot, institutions and development trend of straw bale combustion were analyzed. The running cost of straw baled heating was evaluated. It was found that the straw bale combustion has the characteristics of simple heating process and low operation cost. The operation cost was 19.8 yuan/m2, which was suitable for the industrialization promotion of clean heating in villages and towns. In addition, straw baled heating instead of coal heating can reduce the emission of SO2 by 0.38 kg per square meter and the emission of CO2 by 1.54 kg per year, which has a better benefit of environmental protection. In terms of technology popularization, the industrial system of straw bale combustion in developed countries in Europe is relatively mature, by contrast, the industrial system of straw bale combustion in China is still in the early stage, there are also some large-scale straw bale combustion projects in Liaoning province, Heilongjiang province, Hebei province and other areas, which have achieved good results. Straw bale combustion technology had gradually attracted the attention of scientific researchers. Developed countries in Europe had made some progress in the field of straw bale combustion, such as combustion mechanism, boiler structure, reduction of flue gas emission, etc. And at present, the research of combustion technology focuse on flue gas emission reduction and environmental impact assessment. The existing straw bale combustion technology still has some problems, such as insufficient combustion, unclear generation mechanism of flue gas pollutants, higher NOx and particle emission. It is suggested that we should pay more attention on research of characteristics of pollutant emission, and it is encouraged to reduce the generation of flue gas pollutants from the source. [ABSTRACT FROM AUTHOR]

As a kind of rural residential regions, scattered residential regions in the fields are the inevitable outcome of large-scale habitat-based regions that cannot meet the needs of agricultural planting activities. The rapid development of scattered residential regions in the fields would reduce the effective cultivated land region and cause waste of land resources. Therefore, in order to clarify the influence mechanism of scattered residence pattern in Heilongjiang reclamation region, taking 859 Farm under the jurisdiction of Jiansanjiang Administration Bureau of Heilongjiang reclamation area as the research region, this paper used spatial analysis, coupling degree model, multivariate statistical analysis to explore the influence mechanism of scattered residence pattern. The results show that: 1) 859 Farm has both large-scale habitat-based regions and scattered residential regions in the fields. The number of habitat-based regions is relatively small and the land use mode is relatively intensive. However, some farmers still own scattered residential regions in the fields while owning large-scale habitat-based regions, and the number is relatively large, about 15 times that of large-scale habitat-based regions. It also shows the spatial differentiation characteristics of dense central region and sparse east and west, resulting in extensive residential land use in the study region, reducing the effective cultivated land region and intensifying the contradiction between supply and demand of farm land resources. 2) The average value, the maximum value and the median value of the coupling degree between scattered residential regions in the fields and agricultural planting activities in the study region are 0.52, 1.00 and 0.60, respectively. The coupling degree between the systems is relatively high. Moreover, the spatial differentiation characteristics of coupling degree between scattered residential regions in the fields and agricultural planting activity system and the distribution state of kernel density show spatial consistency. Agricultural planting activities are related to scattered residential regions in the fields to a certain extent, so cultivated land structure, cultivated land region, field fragmentation, tillage radius and deviation distance are the influencing factors of scattered residential regions in the fields in the study region. 3) The main factors influencing the pattern of scattered residential regions in the study area are the attributes of cultivated land (tillage radius, cultivated land region, fragmentation degree of cultivated land) and the status of cultivated land use (cultivated land structure), while the influence of deviation distance is slightly small and is not the main factor. Cultivated land structure and tillage radius are the direct factors, while cultivated land region and field fragmentation are the indirect influencing factors. The mismatch between cultivated land structure and tillage radius makes the study region show the regional characteristics of gathering in the middle and dispersing in the east and west. [ABSTRACT FROM AUTHOR]

Wheat straw returning is one of the main ways to improve soil fertility. Long-term straw returned to field combined with chemical fertilizer can maintain soil fertility. It should be combined with crop rotation system and fertilization management to maximize advantages and avoid disadvantages. The impact of straw returned to field on crop yield and how to fertilize when straw returning are the issues of great concern to agricultural producers. In order to clarify the effect of long-term straw returned to field in wheat-bean rotation on crop yield and soil nutrient, this paper conducted the experiments in the long-term positioning experimental station in Heihe district of Heilongjiang province, and adopted split-plot test method. The main treatment was straw returning to field and non-returning to field, secondary treatment was different fertilization for low, medium and high level. The experiment started in 1980 with wheat-soybean-wheat and wheat-soybean rotation models. The effects of wheat straw returning to field and different fertilization levels on crop yield under wheat-soybean rotation conditions were investigated for 38 consecutive years (1980-2018). The results showed that there was no significant difference in years of yield of wheat, soybean or wheat planted every other year after wheat straw returning. The medium-fertilizer was 7.42%-10.81% higher than that of low-fertilizer area on soybean with continuous fertilization, achieved significant difference level. The yield of wheat increased by 14.52%-19.33% in high-fertilizer area compared with low-fertilizer area. The effect of wheat straw returning on soybean yield was 5.91% higher than that of non-returning in the early stage (1-6 season) and 7.52% higher in the late stage (7-16 season). The yield of wheat increased by 0.31% and 0.22% in early stage (1-5 seasons) and late stage (6-16 seasons) compared with non-returning to field. Generally speaking, after wheat straw returning to the field, the frequency of crop yield reduction in the early stage is high, while the frequency of yield increase in the later stage is high. In Heihe area, the long-term application of wheat straw to field had no significant effect on soil organic matter, total nitrogen, alkali nitrogen, total phosphorus, available phosphorus and total potassium, while the content of available potassium increased significantly. Long-term fertilization had a significant impact on soil nutrients. High fertilizer level could significantly increase the contents of soil organic matter, total nitrogen, alkali nitrogen and total phosphorus. Long-term fertilization also reduces soil pH value, leading to acidification of soil. [ABSTRACT FROM AUTHOR]

In order to improve the efficiency and accuracy of the quantitative prediction of soil nutrient content in black soil of Heilongjiang province, in this paper, we utilized statistical theory and spectral analysis method, researched the relationship of three kinds of soil nutrient content and soil spectrum to established hyperspectral inversion model of soil total nitrogen, available phosphorus, available kalium content. We acquired the aerial hyperspectral data by using CASI-1500 and SASI-600 linear array push-broom imaging spectrometers. Preprocessing of calibration and atmospheric radiation correction of Airborne Hyperspectral raw radiation data was studied. 96 samples were evenly sampled. In order to increase the representativeness of samples, 96 groups of samples were collected from 3-5 samples collected from 15 meters around the sampling point, and 1.5 kg was retained after mixing. After air-drying, mixing and grindingetc, it is used for the contents of total nitrogen, available phosphorus and available kalium were obtained through laboratory tests. The content of total nitrogen, available phosphorus and available kalium was determined by NaOH diffusion method, NaHCO3 extraction-molybdenum blue colorimetry and NH4OAC extraction-flame photometry. Referring to Kennard-Stone method, 72 groups of representative samples were selected as model samples for nutrient content prediction, and 24 groups were model prediction samples. 96 black soil samples were sorted according to nutrient content, and the spectral transformation in the visible near red range was analyzed. The change rule of total nitrogen is that the reflectance decreases with the increase of content. The first order differential spectra at 580 nm were significantly correlated with total nitrogen and available phosphorus content, with a correlation coefficient of -0.43 and -0.36, respectively. The first-order differential spectra at 1730-2200 nm were significantly correlated with K2O, and the maximum correlation coefficient was -0.31. Compared with the original spectral waveform, the correlation coefficient between the first derivative and three nutrient contents fluctuated sharply, and the positive and negative cross-sections were relatively sharp, with more peak coefficients. After spectral contrast analysis and correlation coefficient calculation, 86 bands with higher correlation coefficient were selected for the study under the first order differential variation. On black soil airborne hyperspectral data processing, the application of partial least squares regression (PLSR) and BP neural network method respectively establish soil nutrient content of high spectral quantitative inversion model. The results showed that RPIQ values (Difference between the third and the first quartile of sample observations ratio to RMSE) of total nitrogen PLSR and BP neural network prediction model were 2.42 and 2.80, respectively. The RPIQ values of effective phosphorus PLSR and BP neural network model were 0.83 and 1.67 respectively. The RPIQ values of the available kalium PLSR and BP neural network models were 2.00 and 2.33 respectively. Experiments showed that the spectral quantitative prediction model of soil total nitrogen and available kalium has good accuracy and prediction ability. Nitrogen, phosphorus and potassium, and the spatial distribution of nutrient content in black soil were obtained. However, the prediction effect of effective Phosphorus was not particularly ideal, which could only meet the requirements of approximate quantitative prediction. At the same time, the BP neural network modeling has better accuracy and prediction ability than the partial least square modeling, and the prediction accuracy increased by 6.5%, 10.1% and 6.6% respectively. Due to the limitation of soil samples and other conditions, more samples are needed to verify the universality of the model. More data mining methods are expected to establish more robust prediction models, which will provide more reliable information for the prediction and evaluation of black soil quality information. [ABSTRACT FROM AUTHOR]

Lodging has been regard as one of the major destructive factors for crop quality and yield, resulting in an increasing need to develop cost-efficient and accurate methods for detecting crop lodging in a routine manner. Nowadays, rapid evolvement in unmanned aerial vehicle (UAV) and sensor technology has allowed high accurate and more accessible in monitoring crop development and health status with adequate temporal, spatial, and spectral resolutions. Compared with satellite and airborne photogrammetry, UAV with proper sensors offer a flexible, convenient, and cost-effective way to provide desired and customized observations on crop fields. Previous studies have extensively examined and verified the potential of UAV-based lodging recognition by leveraging photogrammetric algorithms, geospatial computing analysis, as well as pertinent agricultural expertise. As a substantive extension of previous published proceeding papers, this work presents a complete UAV-based survey methodology for monitoring lodging maize. Multispectral images of lodging mature maize in Youyi farm of Heilongjiang Province were collected to extract the lodging area. There were 4 crop forms in the research area: not-lodging maize with green leaves, not-lodging maize with yellowish leaves, lodging maize with yellowish leaves, and black shadows, based on the multispectral image. The 2 vegetation indexes and 8 co-occurrence measures texture features were calculated, and the feature sets of maize lodging area extraction was constructed on the basis of the above 2 kinds of predictors and spectral reflectivity features. 5 types of maize lodging identification feature sets were sifted, which included spectral feature set, normalized difference vegetation index (NDVI) feature set, red edge normalized difference vegetation index (NDVIR-edge) feature set, single-class texture feature set and multi-class texture feature set. The maximum likelihood method was used to identify maize lodging for all feature sets. Finally, we analyzed the classification error of 4 crop morphology, extraction error and Kappa coefficient of lodging area under different features. The results showed that maize lodging area extracted by spectral feature set and NDVI feature set was larger than measured lodging area, which mainly because the wrong classification of not-lodging B pixels into lodging pixels, while the main reason for the inaccurate maize lodging area obtained by NDVIR-edge feature was that the not-lodging B maize and the not-lodging maize affected by edge effect were classified into lodging. Extraction area of lodging maize by single texture feature set was smaller because some of the not-lodging B maize pixels were classified as lodging pixels, but more lodging pixels was misclassified as not-lodging pixels. Single and multi-class texture feature sets could remove the shadow of blade gap well with appropriate texture filtering window selected, but multi-class feature set had higher extraction accuracy. It was difficult to distinguish the lodging maize from the not-lodging maize with yellowish leaves in mature period, and there was no significant difference in spectral reflectance feature between the 2 crop morphology. Therefore, when we identified these 2 types of crop morphology, a large number of misclassification pixels would be generated. The multi-class texture features extracted from UAV multispectral images could accurately extract maize lodging area. The average error of 4 crop morphology was 9.82%, the extraction error of lodging area was 3.40%, and the Kappa coefficient was 0.84. [ABSTRACT FROM AUTHOR]

Straw returning to the filed can not only improve soil fertility, but also alleviate the imbalance of nitrogen, phosphorus and potassium, improve crop yield and quality, and reduce the cost of agricultural production. Rice straw is decomposed gradually by microorganisms in the soil, which can release nitrogen to the soil for rice growth. Nitrogen released from straw can be divided into expended nitrogen and nitrogen retained in soil. Expended nitrogen can be further divided into nitrogen absorbed by plant and lost nitrogen. 15N tracer technology is an effective means to study the nitrogen budget of farmland, by which we can accurately grasp the status of nitrogen utilization and residue, and analyze the nitrogen utilization efficiency of straw. Understanding the utilization rate of straw nitrogen is the premise of fertilization regulation and control. Heilongjiang Province still lacks the utilization rate of nitrogen in rice straw and the technical achievements of nitrogen regulation and control under straw returning conditions. In this paper, we take Qianjin Farm(132°17′E,47°34′N), Sanjiang Plain as test site and the albic soil as the test soil. we conduct a series of experiments during nitrogen regulation and control period including 15N straw labeling tracer test and straw returning nitrogen optimization test, the utilization rate of nitrogen in straw after rice straw returns to the albic soil is defined and the optimized application technology of nitrogen fertilizer after rice straw returns to the albic soil is summarized, so as to provide theoretical basis and technical guidance for optimized application of nitrogen fertilizer after straw returns to the field. The results showed that, according to 15N isotope tracer, the contribution rate of straw nitrogen in the albic soil to rice plant nitrogen accumulation was 6.49%~7.48%, 3.26%~4.16% to stem and leaf nitrogen accumulation, 8.67%~9.74% to seed; the total nitrogen use efficiency of straw was 6.51%~7.65% in the current year, and the adjustment of C/N ratio was beneficial to improving straw nitrogen utilization rate. Field experiments showed that the nitrogen application rate under straw returning was 10% lower than that under conventional nitrogen application for three consecutive years, and the field with good drainage had the effect of increasing yield, with the average yield increase by 6.17% for three years, and the yield with the reduction of nitrogen by more than 20% was low and unstable. Balanced and basal nitrogen reduction was suitable in nitrogen reduction period, and the yield was reduced significantly in case of fertilizer for tillering and panicle with nitrogen reduction; the field with poor drainage was not suitable for nitrogen reduction, otherwise, it led to yield reduction. There are differences in nitrogen regulation and control after straw returns to different kinds of soil. The corresponding measures for nitrogen management should be formulated according to soil conditions. [ABSTRACT FROM AUTHOR]