Evaluation of potassium application on tomato performance and rhizosphere bacterial communities under negative pressure irrigation of greenhouse-grown

Abstract

The study investigated the response to five levels of potassium (K) fertilizer addition on tomato (Solanum lycopersicum L.) performance and soil bacterial communities by negative pressure irrigation (NPI) over two consecutive years. The application of K fertilization positively affected tomato performance under NPI, as indicated by increased yield, quality, growth, and nutrients’ contents of tomato compared with no K addition treatment. High-throughput sequencing of the rhizosphere soil revealed that K additions significantly affected in the bacterial diversity indices according to Chao1, Ace, and Shannon. K addition significantly increased the relative abundance of Gemmatimonadetes and decreased the level of Planctomycetes. There were very prominent increases in the levels of the genus Opitutus, but reduced the content of Sphingomonas and Bdellovibrio compared with no K addition treatment. Furthermore, application of 150?kg K ha^?1 (K150) was considered to be beneficial for plant growth and rhizosphere bacterial diversity of tomato. The tomato yield under K150 was considerably increased by 58% and 47% compared with no K addition treatment in 2016 and 2017, respectively. The K150 showed the highest K fertilizer utilization efficiency compared with other K treatments, with K contribution rate and K agronomic efficiency reaching 36.7 and 62.9 as well as 32.0 and 53.6 in 2016 and 2017, respectively. Therefore, these findings also demonstrate that K application under NPI not only promotes yield and quality of tomato fruits but also positively affects the rhizosphere microbiome.     

乡村企业政企难分的原因与负效应

感情上的留恋，企业的阻力，认识上的误区和乡镇干部“利益”的驱动等原因导致乡村企业政企难分。由此产生了乡村企业盲目追求发展速度、效益低；分配的随意性和加大了乡村党政包袱；损害企业利益，维持乡村党政自身地位；阻碍了乡村企业相对集中；影响了国家调控政策的执行和增加了乡村企业资产存量的损失等负效应。     

文化负迁移对英语词汇释义的影响

负迁移指一种学习对另一种学习起干扰或抑制作用的现象。在外语学习中最容易犯的错误就是把母语的语用习惯套在目的语上,从而造成误解。在词汇学习中,应把语言学习与文化品味结合起来,注意中西文化的差异,以消除文化负迁移对词汇理解的影响。     

福州市空气负离子空间变化特征

采用美国进口的空气离子测定仪,对福州市空气负离子浓度的空间变化情况进行了初步的实测与研究,并以单极系数和空气离子评价指数为标准对其空气质量进行评价。结果表明:从福州市中心向郊区空气负离子浓度逐渐增大,单极系数逐渐减小;有林地区空气负离子浓度明显高于无林地区,一般情况下阔叶林地空气负离子浓度高于针叶林地。     

野生动物资源负价值的评价方法研究

随着生态环境的日益改善,野生动物资源的数量急剧增加,某些物种已经对当地农民的生产生活造成损害,为了全面评估野生动物资源所造成的损害,本文对野生动物资源负价值的定义及表现形式作了简要的概括,在此基础上,初步提出了野生动物资源负价值的评价方法,主要包括野生动物造成的财产上的损失和人身伤害,其中财产上的损失主要包括农作物、树木、牧草、牲畜等的损失,主要采用直接市场法评价;人身伤害不仅包括身体上的创伤还包括精神和心理上的伤害,主要采用意愿调查法进行评价。 西北林学院学报23卷第4期韩嵩等野生动物资源负价值的评价方法研究关     

Effect of Indoleacetic acid （IAA） on the Negative Phototropism of Rice Root

To explore the effects of IAA on negative phototropism of rice (Oryza sativa L) root, agar block containing IAA was unilaterally applied on root tip to examine the phototropic response of root to exogenous IAA, and microstructure of the bending part was observed with an optical microscope. The growth of seminal roots could be regulated by exogenous IAA as well as light,as a result the root bent towards the site treated, causing asymmetric growth of the root cells at the elongation zone and consequently bending growth. IAA concentration in the shaded side of adventitious root increased much greater at 1.5 h after the start of irradiation. The unequal lateral IAA distribution can be concluded to be the main cause for negative phototropism of rice root.     

龙岩国家森林公园冬季负离子浓度变化特征

于2016年1月份连续7 d,对龙岩国家森林公园5类游憩地15个检测点的空气负离子浓度、气象因子等数据进行实测,进行数据分析,结果表明:(1)园内空气负离子浓度日均值为7 108.06个/cm3,达到世界卫生组织所规定的具有保健效果的浓度;(2)园内林地负离子浓度日变化规律基本为双峰式,在07:00—09:00出现第1次峰值,在13:00—15:00出现第2次峰值;次生林在13:00—15:00达到1 d中的最高值;茶园内空气负离子浓度日变化规律整体呈现从07:00—17:00逐渐下降的趋势;动态水的峰值出现在09:00—11:00,15:00—17:00 2个时段内;(3)园内日均负离子浓度含量从高到低依次为:水体旁、茶园、次生林、空旷地、天然林;(4)气象因子与负离子浓度的相关性研究显示,负离子浓度与相对湿度呈极显著负相关,而同气压呈显著正相关。     

Remote real-time monitoring soil water potential system based on GSM

Aiming at the limitation of traditional measuring soil water potential, the paper presents an information system based GSM to real-time monitor data coming from multiple data sources. The monitoring system, which consisted of monitoring center, GSM transmission channel and data detection terminal, was given. The detection terminal included the measuring station and TS-2 negative pressure meter, which was applied to measure soil water potential. Nowadays the system has been successfully applied to drip irrigation in the cotton field on farm in Xinjiang region. The system provides a feasible technology frame-work for collecting and processing wide geographical distribution data in farmland.