[Effects of the construction of fertile and cultivated upland soil layer on soil fertility and maize yield in black soil region in Northeast China.] / 肥沃耕层构建对东北黑土区旱地土壤肥力和玉米产量的影响.

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. Based on the combination of field plot experiments and demonstration regions, nine study sites with different ecological characteristics were selected from Heilongjiang, Jilin and Liaoning provinces from northeast China, covering dark brown, black, meadow, chernozem, albic, brown and cinnamon soils. There were three treatments in each study site, including maize straw return within 0-35 cm soil layer (CFⅠ), the combination of maize straw and organic manure return within 0-35 cm soil layer (CFⅡ) and conventional agricultural practice without organic amendmentas control (CK). The rate of straw return in CFⅠ and CFⅡ treatments were 10000 kg·hm-2, and full straw for demonstration regions. The rate of organic manure in CFⅡ treatment was 30000 kg·hm-2. Considerable difference in soil fertility were recorded among the nine study sites with the trend of tillage layer > sub-tillage layer, especially for dark brown soil and albic soil. Soil fertility of tillage layer and sub-tillage layer was relatively low both for brown soil and cinnamon soil. The heavy clay and plow pan were pivotal limiting factors of soil fertility for the black soil and the meadow soil. Compared with CK, the concentrations of soil organic matter (SOM), available nitrogen (AN), available phosphorous (AP), and available potassium (AK) in tillage layers was increased on average by 1.85 g·kg-1, 20.16 mg·kg-1, 1.56 mg·kg-1 and 17.2 mg·kg-1 in the CFⅠ and CFⅡ treatments in five study sites with more than two years of treatments. The contents of SOM, AN, AP and AK in sub-tillage layer increased by 2.09 g·kg-1, 12.06 mg·kg-1, 2.18 mg·kg-1 and 3.84 mg·kg-1, compared with tillage layer. CFⅠ treatment significantly enhanced the contents of SOM and AP in both tested soil layers, while CFⅡ treatment significantly enhanced all fertility indices in both tested soil layers. This indicated that the increase of organic amendment return is an effective way to improve soil fertility. Maize yield fluctuated under the combined effect of climatic conditions and soil types. The significant differences in maize yield under CK, CFⅠ and CFⅡ treatments were observed with a trend of CFⅡ > CFⅠ > CK. This result indicated that the construction of fertile and cultivated soil layer could significantly increase maize yield independent of soil types. The construction of fertile and cultivated soil layer based on maize straw return or maize straw and organic manure combined return within 0-35 cm soil layer, could simultaneously increase soil fertility in both tillage and sub-tillage layer, as well as maize yield. We suggested that the selection of approaches of the constructions of fertile and cultivated soil layer should consider soil types and the sources of organic amendments. It should also give priority to soil layers rich in organic manure source to construct fertile and cultivated soil layers.

[Prophylactic immunization of dangguibuxue decoction against Cryptosporidium infection in immune suppressed mice].

OBJECTIVE: To explore the prophylaxis of dangguibuxue decoction, a traditional Chinese medicine made from Angelica sinensis and Radix astragalus, on immunosuppressed mice infected by Cryptosporidium parvum. METHODS: 48 BALB/c mice were randomly divided into 4 groups: normal control (A), immunosuppressed control (B), high dose (C), and low dose (D). Mice in groups B, C and D were intragastrically administered with dexamethasone (DXM) for 8 days, and in the same time mice in groups C and D were given high dose (2 g/kg) and low dose (1 g/kg) dangguibuxue decoction respectively. On the ninth day all mice in groups B, C and D were orally inoculated by 1 x 10(6) oocysts of C. parvum. The amount of oocysts in feces was examined daily since being infected. 11 days after infection, the subset of T lymphocytes in peripheral blood was analyzed with flow cytometry, sIL-2R in serum and sIgA of intestinal fluid were detected by ELISA. Pathological change of duodenum and jejunum was observed microscopically. RESULTS: Compared with the immuno-suppressed control group, there were less oocysts in feces (35.0 +/- 4.21) (P < 0.01) and lighter injury in the intestinal mucosa in mice of the high dose dangguibuxue decoction group. Both the number of CD4+ T lymphocytes (47.483 +/- 4.082) and the ratio of CD4+/CD8+ (2.271 +/- 0.378) increased, sIgA [(320.19 +/- 1.94) ng/ml] in the intestinal fluid elevated and sIL-2R [(321.34 +/- 6.66) ng/ml] in peripheral blood decreased in the high dose group, with a significant difference in comparison to the immunosuppressed group (P < 0.01). All the above-mentioned indices in low dose dangguibuxue decoction group showed no significant difference with the immunosuppressed control group (P > 0.05). CONCLUSION: Administration of high dose dangguibuxue decoction plays a role of prophylaxis on the infection of C. parvum in immunosuppressed mice through improving the immune status.

[Effect of yupingfengsan on the growth of tumor and immunological function in tumor-bearing mice].

AIM: To explore the effect of yupingfengsan on the growth of tumor and immunological function in tumor-bearing mice. METHODS: The models of tumor-bearing mice were established by inoculating the healthy mice with S180 tumor carneus cells cultured in vitro. Then the ratio of tumor restriction was calculated. The phagocytosis activity of phagocytes, the level of NO secreted by phagocytes, the proliferating activity of T lymphocytes and the level of IL-2 were detected in the mice after being treated with yupingfengsan 12 days. RESULTS: yupingfengsan elevated the phagocytosis of phagocytes and the level of NO secreted by phagocytes. It promoted T lymphocytes to transform, and increased the level of IL-2 and the activity of NK cells. CONCLUSION: yupingfengsan can increase the immunological function of tumor-bearing mice and suppress the development of tumor in mice.