Compaction of a Eutric Cambisol under heavy wheel traffic in Switzerland:: Field data and a critical state soil mechanics model approach

Subsoil compaction has become a problem of world-wide concern, especially under highly mechanised agricultural practices. Severe structural degradation impedes plant growth. Therefore, compaction must be limited to layers which can be structurally reclaimed with reasonable effort by tillage. The purpose of this study was to investigate the impact of a single pass with a sugar beet harvester on the soil properties of an unploughed Eutric Cambisol. In autumn 1998 and 1999 field measurements and laboratory testing were carried out in Frauenfeld, Switzerland. The wheel loads were 107 kN in 1998 and 108 kN in 1999. Changes of bulk density, total porosity, macroporosity and pre-consolidation pressure show that compaction effects were restricted to the topsoil (0–0.25 m depth). Below 0.25 m depth no changes were measured. The compaction beneath the tyre was modelled with a two phase finite element model in the framework of critical state soil mechanics. The model predicts the degree and depth of compaction of an Eutric Cambisol caused by a single pass in Switzerland. Modelled data and field results agree quite well.     

栽培穿龙薯蓣田间持水量与光合作用关系的研究

[目的]研究栽培穿龙薯蓣田间持水量与光合作用的关系,为穿龙薯蓣栽培的水分管理提供理论依据。[方法]采用盆栽试验,用CI-340超轻型便携式光合测定仪测定光合参数。[结果]70%的田间持水量是穿龙薯蓣光合能力最强的土壤含水量,此时蒸腾速率和水分利用效率较高。在50%田间持水量条件下,净光合速率日变化均呈明显的双峰曲线;70%田间持水量的峰值出现在中午12时和下午16时,分别为7.3、6.5μmol/(m2·s),有轻微的光合"午休"现象。[结论]栽培穿龙薯蓣以控制土壤水分含量为田间持水量的70%最佳。     

地理国情监测的探索与实践

地理国情监测作为全新型工作、创新性任务,是新时期空间信息科学的重要使命.对地理国情监测的国外发展现状、重要意义和主要技术支撑以及当前主要技术路线和方法进行了讨论,通过山东地理国情普查试生产的实践进行了相关技术方法的探索与分析.     

吡唑醚菌酯与戊唑醇复配对葡萄炭疽病菌增效活性与田间防效

[目的]为筛选防治葡萄炭疽病的高效低毒新型复配药剂,降低有效用药量,提高防治效果,防止与延缓抗药性产生.[方法]本研究采用菌丝生长速率法测定了吡唑醚菌酯、戊唑醇及其复配制剂对葡萄炭疽病菌的毒力,并通过田间试验评价了其对葡萄炭疽病的防治效果.[结果]吡唑醚菌酯与戊唑醇及5∶1、3∶1、1∶1、1∶3、1∶5复配组合对葡萄炭疽病菌的EC50(半最大效应浓度)值分别为1.038 8μg/ml、0.3583 μg/ml、0.612 9μg/ml、0.530 1μg/ml、0.2326 μg/ml、0.232 8μg/ml和0.329 6μg/ml;5种复配组合对葡萄炭疽病菌的增效系数(SR)分别为1.29、1.33、2.29、1.84、1.22,其中以1∶1复配的组合增效作用最大.田间防效调查结果表明,25％吡唑醚菌酯·戊唑醇悬浮剂药剂1 000倍液、2 000倍液、3 000倍液以及430 g/L戊唑醇悬浮剂5 000倍液、250 g/L吡唑醚菌酯乳油2 000倍液对葡萄炭疽病防治效果分别为91.54％、90.80％、82.88％、76.43％、74.10％.[结论]因此,吡唑醚菌酯和戊唑醇复配防治葡萄炭疽病增效明显,其中以质量比1∶1混合后对葡萄炭疽病菌增效作用最为显著,果穗套袋前采用25％吡唑醚菌酯·戊唑醇悬浮剂1000～2 000倍液浸果防治葡萄炭疽病害防效均达90％以上.     

湖南双季杂交晚稻对细菌性条斑病的田间抗性及条斑病发生动态

为明确湖南双季杂交晚稻品种对细菌性条斑病的田间抗性表现及双季晚稻细菌性条斑病的发生特点,通过2014—2016年连续三年的田间系统调查与统计分析,研究了湖南双季杂交晚稻主栽品种上条斑病的田间发病情况及大田细菌性条斑病的发生流行动态,绘制了条斑病发生动态与进展曲线图。结果表明,12个湖南双季杂交晚稻主栽品种中,仅‘深两优5814’、‘天优3301’、‘欣荣优华占’、‘五优308’等4个品种田间抗性表现较好,其余8个品种包括近年种植面积较大的品种如‘天优华占’、‘广两优2010’、‘威优227’、‘H优518’等均表现易感条斑病,揭示湖南双季杂交晚稻对条斑病的抗性水平整体较低;湖南双季杂交晚稻条斑病的始发期在8月中旬,约8月11—15日间,流行高峰期在9月上中旬。上述研究结果可为湖南双季杂交晚稻生产上适时防治细菌性条斑病提供科学依据与指导。     

蓝藻有机肥的制备及其对水稻生长的影响

[目的]为了实现蓝藻无害化处理和资源化利用,将蓝藻制备成有机肥,并应用于水稻种植。[方法]将打捞上岸蓝藻藻泥与环境诱导材料以100∶2混合,中温发酵制备有机肥,发酵后的蓝藻有机肥含有较高的养分,经权威机构检测为无毒、无公害环保有机肥。蓝藻有机肥与化肥以10∶1和20∶1的比例在水稻田中进行肥效比较,在水稻生长期间定期测量株高,收割前测量穗长、穗重等指标,收割后测稻谷品质等。[结果]藻肥不仅能够部分提高水稻产量,而且能够显著提高稻米品质,尤其是蛋白质含量比化肥种植的水稻高出55.8%,而直链淀粉和胶稠度分别高出9.3%和7.9%。[结论]蓝藻发酵制备的有机肥安全、有效,只有广阔的应用前景。     

安徽自然环境及皖南沿江平原植物区系的概述

对皖南沿江平原地区植物区系进行实地考察,对重要的、有代表性的植物进行鉴定,并分类统计,共155种植物,分属70科,其中148种可作药用,占总数的96%,该研究为科研工作者提供了方便而宝贵的植物研究材料,以期更好地利用和保护该地区珍稀的植物资源和生态多样性。     

2004-2015年通海县露地蔬菜基地土壤养分变化

摸清通海县露地蔬菜基地2004-2015年耕作土壤养分含量变化状况,以期为合理施肥提供参考依据,进行了田间取样与室内检测对比分析.结果 表明:2015年通海露地蔬菜基地土壤pH 7.57,有机质平均含量43.8 g/kg;有效N平均含量170mg/kg,＞151 mg/kg的田块占67.5％;土壤有效P平均含量111....     

TAK1 regulates fibrosis of renal tubular epithelial cells by regulating p38 MAPK signaling pathway

AIM:To investigate the effect of transforming growth factor-β (TGF-β) activated kinase 1(TAK1) on renal tubular epithelial fibrosis. METHODS:The renal tubular epithelial cell line HK-2 was used as the research object. After induced by TGF-β1, real-time PCR and Western blot were used to detect the expression of TAK1 in the HK-2 cells. TAK1 shRNA lentivirus was used to infect HK-2 cells, real-time PCR and Western blot were used to determine the interference effect on TAK1 expression in the HK-2 cells with TGF-β1 stimulation. Under the condition of treating with p38 MAPK activator anisomycin, the levels of type I collagen and type Ⅲ collagen in the supernatant, and the protein levels of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF) and p-p38MAPK^{Thr 180/Tyr 182} in the HK-2 cells with TAK1 knock-down were determined by ELISA and Western blot, respectively. RESULTS:TGF-β1 significantly increased the expression of TAK1 in the HK-2 cells(P<0.05). TAK1 shRNA significantly decreased the expression of TAK1 in the HK-2 cells with TGF-β1 stimulation. Type I collagen and type Ⅲ collagen secreted by the HK-2 cells after treatment with TGF-β1 were increased, the protein levels of α-SMA, CTGF and p-p38MAPK^{Thr 180/Tyr 182} were also increased(P<0.05). Knock-down of TAK1 expression significantly inhibited the secretion of type I and type Ⅲ collagen, reduced the protein levels of α-SMA, CTGF and p-p38MAPK^{Thr 180/Tyr 182} in the TGF-β1-induced HK-2 cells(P<0.05). Treatment with p38 MAPK activator reversed the inhibitory effect of TAK1 knock-down on the secretion of type I and type Ⅲ collagens, and the protein levels of α-SMA, CTGF and p-p38 MAPK^{Thr 180/Tyr 182} in the HK-2 cells(P<0.05). CONCLUSION:Knock-down of TAK1 expression attenuates the TGF-β1 induced fibrosis of renal tubular epithelial cells by inhibiting p38 MAPK signaling pathway.     

Inhibitory effect of metformin on alveolar epithelial-mesenchymal transition in lung tissue of rats with pulmonary fibrosis

AIM: To study the inhibitory effect of metformin on alveolar epithelial-mesenchymal transition (EMT) in rats with pulmonary fibrosis and the possible mechanism. METHODS: SD rats (n=48) were used, 12 of which were set up as normal control group, and 36 of which were induced by bleomycin (5 mg/kg) by tracheal instillation to establish pulmonary fibrosis. The pulmonary fibrosis rats were randomly divided into bleomycin group, low dose (100 mg/kg) of metformin group, and high dose (300 mg/kg) of metformin group. The rats in metformin groups were given the corresponding dose of metformin daily for 4 weeks. HE staining and Masson staining were used to observe the changes of lung histopathology and collagen deposition. Real-time PCR, Western blot and innunohistochemical staining were used to detect the mRNA and protein expression of α-smooth muscle actin (α-SMA), E-cadherin, vimentin, zonula occludens-1 (ZO-1), collagen I, collagen III and transforming growth factor-β₁ (TGF-β₁), and the protein phosphorylation levels of Smad2/3 and extracellular signal-regulated kinase 1/2 (ERK1/2) were also determined. RESULTS: Metformin up-regulated the expression of E-cadherin and ZO-1, down-regulated the expression of α-SMA, vimentin, collagen I and collagen III, and the protein phosphorylation levels of Smad2/3 and ERK1/2 were also decreased (P<0.05). CONCLUSION: Metformin inhibits alveolar EMT in the rats with pulmonary fibrosis, and its mechanism may be related to the inhibition of TGF-β₁ signal transduction pathway.