[Construction effect of fertile cultivated layer in albic soil Ⅰ Effects of inversion tillage with organic mate-rials on the redistribution of organic matter in surface layer of albic soil].

Soil organic matter serves as a crucial indicator for soil quality. Albic soil, characterized by a barrier layer, exhibits limitations in organic matter content, which can adversely affect crop growth and development. To elucidate the impact of deep mixing of various organic materials on the redistribution of organic matter in the surface soil of albic soil could provide theoretical and technical insights for establishing suitable plough layers for albic soil in Northeast China.

Effects of the construction of fertile and cultivated soil layer on soil fertility and maize yield in Albic soil.

We examined the effects of fertile soil layer construction technology on soil fertility and maize yield with a 3-year field experiment in Albic soil in Fujin, Heilongjiang Province. There were five treatments, including conventional tillage (T15, without organic matter return) and fertile soil layer construction methods [deep tillage (0-35 cm) with straw return, T35+S; deep tillage with organic manure, T35+M; deep tillage with straw and organic manure return, T35+S+M; deep tillage with straw, organic manure return and chemical fertilizer, T35+S+M+F]. The results showed that: 1) compared with the T15 treatment, maize yield was significantly increased by 15.

[Effects of the construction of fertile and cultivated upland soil layer on soil fertility and maize yield in black soil region in Northeast China.].

Organic amendment return could enhance soil fertility, improve soil structure, and increase crop yield. However, how construction of soil layers can affect soil fertility and crop yield are not fully understood. We examined the effects of constructions of fertile and cultivated soil layer on soil fertility and maize yield in the upland black soil region in Northeast China, to provide theoretical guidance in increasing soil fertility and sustainable development of agriculture.

Long-term application of fertilizer and manures affect P fractions in Mollisol.

Application of phosphorus (P), a major plant nutrient, as fertilizer is critical to maintain P level for crop production and yield in most cultivated soils. While, it may impact the dynamics, limited studies have examined the long-term effects of fertilization on P fractions in a soil profile in Mollisol. A long-term field experiment was conducted at the State Key Experimental Station of Agroecology of the Chinese Academy of Sciences in Hailun county, Heilongjiang Province, China.

[Characteristics of soil fertility during soil fertilization from parent material of a Mollisol in Northeast China].

Based on a long-term field experiment located in the central region of Mollisol in Northeast China, we examined the changes of soil fertility and nutrient supply capacity of the newly-formed soils with pot experiment after 14-year different agricultural management practices from parent material (PM) (down to 2.0-3.0 m depth) of a Mollisol, and finally tried to optimize pre-ferential agricultural practices improving soil fertility of seriously eroded PM.

Labile and recalcitrant components of organic matter of a Mollisol changed with land use and plant litter management: An advanced C NMR study.

Soil organic matter (SOM) changes with land use and soil management, yet the controlling factors over the chemical composition of SOM are not fully understood. We applied quantitative C nuclear magnetic resonance and spectral editing techniques to measure chemical structures of SOM from different land use types. The land use types included a native grassland (nGL), a crop land with straw burning in the field (bCL), a restored grassland (rGL) and a cropland with straw removed out of the field (rCL) for 28years.

Agrobacterium salinitolerans sp. nov., a saline-alkaline-tolerant bacterium isolated from root nodule of Sesbania cannabina.

Two Gram-staining-negative, aerobic bacteria (YIC 5082T and YIC4104) isolated from root nodules of Sesbania cannabina grown in a high-salt and alkaline environment were identified as a group in the genus Agrobacterium because they shared 100 and 99.7 % sequence similarities of 16S rRNA and recA+atpD genes, respectively. These two strains showed 99.

Agrobacterium deltaense sp. nov., an endophytic bacteria isolated from nodule of Sesbania cannabina.

A Gram-negative, non-spore-forming, aerobic rods, strain YIC4121, was isolated from root nodule of Sesbania cannabina grown in Dongying (Yellow River Delta), Shandong Province, PR China. Based on phylogenetic analysis of 16 S rRNA gene sequences, strain YIC4121 was assigned to the genus Agrobacterium with 99.7, 99.

Genetic diversity of indigenous soybean-nodulating rhizobia in response to locally-based long term fertilization in a Mollisol of Northeast China.

The influences of five different fertilizer treatments on diversity of rhizobia in soybean nodule were investigated in a long-term experiment with with four replicates: (1) control (without fertilization), (2) balanced NPK fertilizer (NPK), and (3-5) unbalanced chemical fertilizers without one of the major elements (NP, PK, and NK) in Mollisol in Northeast China. The highest soybean yield was observed in the NPK treatment. Total of 200 isolates were isolated and grouped into four Bradyrhizobium genospecies corresponding to B.

Rhizobium hidalgonense sp. nov., a nodule endophytic bacterium of Phaseolus vulgaris in acid soil.

One Gram-negative, aerobic, motile, rod-shaped bacterium, designated as FH14, was isolated from nodules of Phaseolus vulgaris grown in Hidalgo State of Mexico. Results based upon 16S rRNA gene (≥99.8 % similarities to known species), concatenated sequence (recA, atpD and glnII) analysis of three housekeeping genes (≤93.

[Profile distribution and storage of soil organic carbon in a black soil as affected by land use types].

Taking soils in a long-term experimental field over 29 years with different land uses types, including arable land, bare land, grassland and larch forest land as test materials, the distribution and storage of soil organic carbon (SOC) in the profile (0-200 cm) in typical black soil (Mollisol) region of China were investigated. The results showed that the most significant differences in SOC content occurred in the 0-10 cm surface soil layer among all soils with the order of grassland > arable land > larch forest land > bare land. SOC contents at 10-120 cm depth were lower in arable land as compared with the other land use types.

Change in soil organic carbon between 1981 and 2011 in croplands of Heilongjiang Province, northeast China.

Background: Soil organic carbon (SOC) is fundamental for mitigating climate change as well as improving soil fertility. Databases of SOC obtained from soil surveys in 1981 and 2011 were used to assess SOC change (0-20 cm) in croplands of Heilongjiang Province in northeast China. Three counties (Lindian, Hailun and Baoqing) were selected as typical croplands representing major soil types and land use types in the region.

Abundance and diversity of soybean-nodulating rhizobia in black soil are impacted by land use and crop management.

To investigate the effects of land use and crop management on soybean rhizobial communities, 280 nodule isolates were trapped from 7 fields with different land use and culture histories. Besides the known Bradyrhizobium japonicum, three novel genospecies were isolated from these fields. Grassland (GL) maintained a higher diversity of soybean bradyrhizobia than the other cultivation systems.

Nitrous oxide emissions from Mollisols as affected by long-term applications of organic amendments and chemical fertilizers.

A field experiment was conducted to evaluate the influences of long-term applications of organic amendments and chemical fertilizers on nitrous oxide (N2O) emissions from Mollisols in northeast China and to relate soil N2O fluxes to soil moisture and temperature. A closed-chamber method was used to determine soil N2O flux during the maize growing season in 2011. In the entire maize growing period, cumulative N2O emissions were significantly (all P<0.

[Long-term fertilization on the behavior of aging of the phenanthrene in the black soil aggregates].

The soil samples were collected from the surface (0-20 cm) soil of the long-term fertilizer experiments in black soil areas in Northeast Location Monitoring Field [fertilizers and organic fertilizers (NPOM), no fertilization (NF)], and indoor culture method was adopted to study the behaviour of aging of the phenanthrene different size of soil aggregates and its contributing factors of aging source analysis. The results show that in the beginning of the aging > 2 mm aggregate fraction was a priority adsorbent, while last stage of the aging < 0.053 mm aggregate fraction was the preferred adsorbent.

[Construction effect of fertile cultivated layer in black soil].

The clayey farmland soil in black soil region of Northeast China, due to the existence of thicker plough pan created by unreasonable tillage, is a main limiting factor for local agricultural production. In this paper, a field experiment was conducted to study the construction effect of fertile cultivated layer on crop yield, soil physical properties, soil moisture content, and soil microbial number. After the construction of fertile cultivated layer, the soil had a thicker cultivated layer, and the crop yield was increased.

[Influence of soluble carbon and nitrogen on ammonia volatilization from different thermal zones soil].

A static absorption method was used to study the influence of soluble carbon and nitrogen on ammonia volatilization from different thermal zone soils, such as black soil, red soil and cinnamon soil, performed in laboratory. Results showed that nitrogen application enhanced ammonia volatilization significantly. The amount of ammonia volatilization in cinnamon soil ranged from 14.

[Effects of low molecular organic acids on nitrogen accumulation, nodulation, and nitrogen fixation of soybean (Glycine max L.) under phosphorus deficiency stress].

A greenhouse sand culture experiment was conducted to study the effects of citric acid, oxalic acid, malic acid, and their mixture on the nitrogen accumulation, nodulation, and nitrogen fixation of soybean. After the application of test low molecular weight organic acids, the nitrogen accumulation in the aboveground part of soybean decreased by 17.6%-44.

[Cadmium accumulation and its development tendency in black soil under long-term fertilization].

Based on the long-term field experiment at Hailun Agro-ecosystem Experimental Station of Chinese Academy of Sciences, this paper studied the cadmium (Cd) accumulation, its development tendency, and Cd availability in black soil under effects of long-term application of chemical N and P fertilizers and pig manure. The results showed that under no fertilization, soil Cd concentration had a slight increase. Long-term chemical N and P fertilization increased soil Cd concentration significantly, but soil Cd accumulation had less difference under different N and P fertilization rates.

[Effects of long-term fertilization on enzyme activities in black soil of Northeast China].

In this paper, black soil samples at the depths of 0-20 cm and 20-40 cm were collected from the Hailun Agricultural Ecology Station of Chinese Academy of Sciences to study the effects of long-term fertilization on their urease, invertase, phosphatase and catalase activities and total C and N contents. The results showed that long-term application of chemical fertilizers and organic manure increased the activities of urease, invertase and phosphatase in 0-20 cm and 20-40 cm soil layers in different degree, and the combined application of them increased the activities of the three enzymes significantly, with an increment of 43.6%-113.

[Effects of different land management practices on black soil microbial biomass C and enzyme activities].

In a long-term experimental plot at the Hailun Agricultural Ecology Station of Chinese Academy of Sciences in Heilongjiang Province, Northeast China, the effects of three land management practices including natural restoration, fallowing and cropping on black soil microbial biomass C and enzyme activities at the depths of 0-10, 20-30 and 40-50 cm were investigated. The results showed that at 0-10 cm, soil microbial biomass C and soil urease, phosphatase, catalase and invertase activities were in the sequence of natural restoration > cropping > fallowing, while at 20-30 cm and 40-50 cm, they had less significant differences as those at 0-10 cm. Under natural restoration and cropping, soil microbial biomass C and soil urease, phosphatase and catalase activities decreased with increasing soil depth, while under fallowing, they were higher at 20-30 cm.