[Effects of long-term fertilization on organic nitrogen fractions in aquic brown soil].

The purpose of present research was to investigate how different fertilization regimes altered soil organic nitrogen fractions and their inter-annual dynamics based on a series of long-term experiment (initiated at 1990), including: CK (non-fertilization); M (recycled pig manure); NPK (chemical fertilizer NPK); NPK + M (recycled pig manure with chemical fertilizer NPK). The results showed that soil organic nitrogen components under the different fertilization treatments presented contrastive patterns from the establishment the experiments to 2015. Generally, acid hydrolysable organic nitrogen content increased year by year.

[Study on Leaching Characteristic of Heavy Metal in the Manure-Amended Soil Using ICP-MASS].

Based on an 11-year fertilizer field trial (located at the lower liaohe river plain), the effects of different organic manure application rates on the accumulations of heavy metals (Cu, Zn, Cd and Cr) in surface soil (0-20 cm), and the leaching characteristic and vertical migration pattern of heavy metal have been investigated in this rainfed agro-ecosystem using undisturbed soil columns. The result showed that the content of heavy metal in surface soil was elevated with the increase of manure application. The increasing magnitude was in the order of Cd>Cu>Zn>Cr.

[Study on Contents and Budgets of Cu, Zn and Cd in an Arable Soil Using AAS].

Based on a long-term experiment in Shenyang Experimental Station, the effect of manure application on the contents and budgets of Cu, Zn and Cd in the arable soil was studied. The experiment included four treatments: no mature addition (CK), mature addition 10 t · ha⁻¹ year⁻¹(M1), 25 t · ha⁻¹ year⁻¹ (M2), and 50 t · ha⁻¹ year⁻¹(M3). The result showed that Cu, Zn and Cd in soil were accumulated with manure application and prolongation of experiment, and the accumulative magnitude increased with increasing of manure application.

[Basic features and monitoring methodologies of atmospheric nitrogen deposition].

Atmospheric nitrogen (N) deposition, including dry and wet deposition, is an important inorganic and organic N source for ecosystems, and also a key link of the N biogeochemical cycle. Recently, considerable active nitrogen has been emitted into the atmosphere due to enhanced human activities. High N emission leads to high deposition which has caused a series of environment risks, and more attentions have been focused on this issue.

[Determination of concentrations and distributions of Mn and Zn in maize under different fertilization regime using ICP-AES].

A long-term field experiment and ICP-AES analysis were conducted to study concentration and content of micronutrients Mn and Zn in maize under different fertilization systems. The results were as follows: (1) Concentrations of Mn in maize under NPKM and NPK treatments were significantly higher than those in M and control treatments. The concentration of Zn in grain of maize was similar under different treatments.

[The recycling rate of trace element Fe and Zn in agro-ecosystem using ICP-AES].

Input of trace elements Fe and Zn in the lower reach of Liaohe Plain under different fertilization systems was studied by long-term field experiment and ICP-AES analysis. The results showed that Fe and Zn were mainly from organic manure in agro-ecosystem. The residual rate of organic manure through a feeding-composting cycle in the absence of bedding materials was 21.

[Effects of long-term fertilizations on microbial biomass C and N and bacterial community structure in an aquic brown soil].

Taking a long-term field experiment on an aquic brown soil in the Shenyang Ecological Station of Chinese Academy of Sciences as a platform, the methods of traditional chloroform fumigation and modern PCR-DGGE were adopted to study the effects of different fertilizations on the changes of soil microbial biomass and bacterial community structure. During the whole period of the experiment, there was a similar trend in the dynamic changes of soil microbial biomass C and N. Long-term application of organic manure increased the soil organic C and the soil microbial biomass C and N significantly, while long-term application of chemical fertilizers had significant negative effects on the soil pH and soil microbial biomass C and N.

[Nutrient concentration and storage in different organs of Eucalyptus under effects of nitrogen topdressing].

A field experiment was conducted to study the effects of nitrogen (N) topdressing on the biomass accumulation and nutrient concentration and storage in different organs of two-year-old eucalyptus. Comparing with the control, N topdressing increased the eucalyptus biomass by 24.2%.

[Study on the main influencing factors of black soil spectral characteristics].

To develop soil properties quick measuring methods, promote the development of quantitatively remote sensing studies relating to terrestrial ecosystem, and deepen the application of remote sensing in agriculture, the hyperspectral reflectance of black soil in Songnen Plain, northeast China, was analyzed with spectral analysis methods (continuum removal, spectral angle match and spectral feature fitting) and statistic methods to discover the reflectance spectral characteristics and its influencing factors. The results are as follows: the soil parent material determines the basic characteristics of reflectance of the black soil, which is the mixture of montmorillonite and illite, and consistent with mineral analysis result. Organic matter is the main factor determining the curve shape of black soil reflectance in the region shorter than 1 000 nm, and indirectly influencing the reflectance in the region longer than 1 000 nm because of the correlation with soil moisture and mechanical composition.

[Effects of land use type on soil organic carbon storage in aquic brown soil].

The profile distribution of soil organic carbon (SOC), its storage, and carbon/nitrogen (C/N) ratio at the depth of 0-100 cm under different land use types were investigated in this paper. The results showed that the profile distribution of SOC varied significantly with land use type. The SOC contents in each soil layer in forestland, mowing land and wasteland were all higher than that in agricultural land.

[Decomposition process and residual rate of organic materials C and N in soils].

By using nylon mesh bags and sand filter tubes, this paper studied the decomposition of organic materials in the soils at Shenyang and Hailun eco-experimental stations of CAS to investigate the dynamic changes of their organic C and N during decomposition. The results showed that the decomposition process could be divided into two phases, i.e.

[K fertility and K deficit index of aquic brown soil under different fertilization systems].

A 15-year fertilization experiment was conducted on an aquic brown soil to study the variations of its K fertility and the index of K deficit under different fertilization systems. The results indicated that no K application accelerated the depletion of soil K, representing a certain decrease of soil available and slow-release K. Applying K alone could not keep soil K in balance, still having a decrease of soil available and slow-release K.

[Research advances in water-fertilizer effect on dry land farmland].

Water and fertilizer are the keys in improving dry land productivity, and the main factors limiting the agricultural development in dry land regions. For our food security and agricultural sustainable development, it' s of significance to bring the effect of water and fertilizer on increasing yield into full play. This paper introduced the design principles of several commonly used methods in researching the effect of water and fertilizer, e.