不同改良措施提高沙地初级生产力的机制:土壤微环境

土壤微环境恢复是实现沙地和沙化草地恢复的基础。然而,改良措施如何作用于土壤微环境从而提高沙地初级生产力的机制并不清楚。本研究在内蒙古锡林郭勒半固定沙地开展改良措施修复试验,设置对照、立体措施(结皮+保水剂)和综合措施(撒种+结皮+保水剂)处理,测定土壤物理性状(土壤容重、团聚体、温度和水分)和植物生物量,研究不同改良措施对沙地土壤微环境的影响。结果表明:立体措施和综合措施均改善了土壤结构(土壤容重降低、水稳性大团聚体增加),降低了水分蒸发,提高了土壤入渗,从而提高了土壤含水量;两种改良措施均降低了夏季日均温,这有利于减少水分蒸发,立体措施提高了早春日均温,可能会促进植物的萌发,从而提高雪水的利用率;两种改良措施均降低了温度日变化,白天较低的温度有利于降低水分的蒸发;综合措施较立体措施增加了撒种处理,提高了植物生物量,反过来又改善了土壤微环境,改良效果更佳。本研究揭示了立体措施和综合改良措施改善沙地土壤微环境,从而提高初级生产力的机制,为沙地和退化草原改良提供了理论支持,同时也具有重要的实践意义

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies