[Effects of foliar selenium fertilizer on fruit yield, quality and selenium content of three varieties of Vitis vinifera]. / 叶面喷施硒肥对3个葡萄品种果实产量、品质和硒含量的影响.

With three grape varieties, Red Barbara, Summer Black and Hutai No. 8 as test mate-rials, we investigated the effects of foliar spraying of organic selenium fertilizer on greenhouse grape quality and selenium content. The results showed that spraying 12 mg·L-1 amino acid chelated selenium-enriched foliar fertilizer on grape leaves significantly increased selenium content and the quantity and quality of grape yield, including the contents of soluble sugar, organic acid, soluble protein, soluble solids, vitamin C and proanthocyanidins. However, there was no increase in resveratrol. Among the three varieties, selenium content of Summer Black in 2017 and 2018 was increased by 36.7% and 37.1%, respectively, being higher than that of Red Barbara and Hutai No. 8. Red Barbara sprayed with selenium fertilizer had better quality due to high sugar and low acid contents, as well as high health-care components. Moreover, the selenium content of Hutai No. 8 in 2018 was 53.26 µg·kg-1, higher than the others, indicating a stronger ability of selenium enrichment. We concluded that the increase range of Se content was larger in Summer Black, Red Barbara showed the better nutrition value and quality, and Hutai No. 8 was a suitable variety for selenium-rich grape production.

[Soil respiration variations in winter wheat field in different previous crops and its influencing factors].

This study was to define the Variations of soil respiration, the response of influence factors to soil respiration and carbon sink in the total growing season, in winter wheat field of different previous crops. The results showed that: (1) as soil depth increases, the response of temperature to soil respiration rate also increased with a lag; (2) the soil respiration rate was quadric to soil moisture, phosphorus, potassium, soil urease activity, soil temperature, soil moisture as the main factors had an effect on soil respiration rate; soil temperature had the stronger effect on soil respiration rate when potassium had the weaker effect on soil respiration rate; (3) the average carbon emission rate in wheat filed of different previous crops showed as follow: Pepper of previous crops > celery of previous crops > corn of previous crops > eggplant of previous crops. The intensity of carbon "sink" displayed as follow: eggplant of previous crops > celery of previous crops > corn of previous crops > pepper of previous crops. As for the trials of this study, although the soil respiration rate is highest in the winter wheat filed of previous pepper, the amount of carbon fixed is the most. Its ratio of net primary productivity (NPP) and soil carbon release quantity was highest, so carbon sink was the strongest. If rotation planting was arranged according to the purpose of increasing carbon sink and reducing carbon emissions, pepper was relatively appropriate stubbles crop, followed by corn crop, celery and eggplant.

[Effects of soil covering on solar greenhouse pepper water use efficiency and soil nitrate N and available phosphorus contents].

A greenhouse study on the effects of soil covering on pepper (Capsicum anmuum L.) water use efficiency and soil nitrate and available phosphorus contents showed that straw mulch + plastic film mulch could get the highest pepper yield water use efficiency (33.04 kg . m(-3)) and economic water use efficiency (50.22 yuan . m(-3)), followed by plastic film mulch, with the two parameters being 18.81 kg . m(-3) and 28.57 yuan . m(-3), respectively. Significant differences of nitrate N content in 0-20 cm soil layer were observed among different treatments. The control had the highest nitrate N content (50.33 mg . kg(-1)), followed by straw mulch (31.98 mg . kg(-1)) and straw + plastic film mulch (31.96 mg . kg(-1)), and plastic film mulch and applying water preserving agent. Compared with the control, soil covering could increase the nitrate N use efficiency of pepper, and decrease the accumulation of nitrate N in plough layer. In 0-20 cm soil layer, treatment plastic film mulch had the lowest available phosphorus content (0.72 mg . kg(-3)), and the second (0. 92 mg . kg(-1)) was the treatment straw + plastic film mulch. Treatments straw + plastic film mulch and plastic film mulch could increase pepper fruit yield and fertilizer use efficiency, and decrease fertilizer loss.