Estimating spatial mean soil water contents of sloping jujube orchards using temporal stability

Estimating spatial mean soil water contents from point-scale measurements is important to improve soil water management in sloping land of semiarid areas. Temporal stability analysis, as a statistical technique to estimate soil water content, is an effective tool in terms of facilitating the upscaling estimation of mean values. The objective of this study was to examine temporal stability of soil water profiles (0–20, 20–40, 40–60 and 0–60 cm) in sloping jujube (Zizyphus jujuba) orchards and to estimate field mean root-zone soil water based on temporal stability analysis in the Yuanzegou catchment of the Chinese Loess Plateau, using soil water observations under both dry and wet soil conditions. The results showed that different time-stable locations were identified for different depths and the temporal stability of soil water content in 20–40 cm was significantly (P < 0.05) weaker than that in other depths. Moreover, these time-stable locations had relatively high clay contents, relatively mild slopes and relatively planar surfaces compared to the corresponding field means. Statistical analysis revealed that the temporal stability of root zone soil water (0–60 cm) was higher in either dry or wet season than that including both, and soil water exhibited very low temporal stability during the transition period from dry to wet. Based on the temporal stability analysis, field mean soil water contents were estimated reasonably (R² from 0.9560 to 0.9873) from the point measurements of these time-stable locations. Since the terrains in this study are typical in the hilly regions of the Loess Plateau, the results presented here should improve soil water management in sloping orchards in the Loess Plateau.     

Effect of ammonia and nitrite on vigour,survival rate,moulting rate of the blue swimming crab <Emphasis Type="Italic">Portunus pelagicus</Emphasis> zoea

The effects of ammonia and nitrite on vigour, survival rate, moulting rate of zoea of blue swimming crab, Portunus pelagicus, were studied. A total of five nitrite-N treatments (26.67, 53.34, 106.68, 213.36, 426.72 mg/l) and a control (no nitrite-N added) were set up for the acute nitrite-N toxicity experiment; a total of five ammonia-N treatments (8.43, 16.86, 33.72, 67.44, 134.88 mg/l) and a control (no ammonia-N added) were set up for the acute ammonia-N toxicity experiment. The results showed that the vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 53.34 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of nitrite-N were 179.47, 76.56, 66.70, 37.49, 25.01, 25.35, 25.34 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The vigour, survival rate and moulting rate of zoea of the blue swimming crabs exposed to over 16.86 mg/l were significantly different (P < 0.05) from the control group. The zoea LC₅₀ values (mg/l) of ammonia-N were 51.04, 39.62, 38.72, 24.43, 16.90, 13.42, 11.16 mg/l for 24, 36, 48, 60, 72, 84, 96 h, respectively. The zoeae are highly sensitive to ammonia and nitrite, and the toxicity of ammonia and nitrite on Portunus pelagicus decrease with development of this crab.     

大白菜软腐病苗期抗性及其与成株期抗性的关系

对６６个大白菜品种苗期抗性的测定结果表明，不同品种对细菌根系侵入和潜伏侵染的抗性存在显著差别；同一品种幼苗对侵入侵染的抗性与对潜伏侵染的抗性间没有相关性。幼苗期的组织含菌量与成株的田间软腐病发病程度有一定的相关性。并初步建立了大白菜对软腐病苗期抗性的鉴定方法。     

Effects of dietary oregano essential oil supplementation on growth performance,intestinal antioxidative capacity,immunity, and intestinal microbiota in yellow-feathered chickens

Essential oils are plant-derived aromatic volatile oils, and they contain bioactive compounds that have been shown to improve poultry nutrition. In this study, we investigated the effects of oregano essential oil (OEO) on intestinal antioxidative capacity, immunity, and gut microbiota of young yellow-feathered chickens. A total of nine hundred and sixty 1-d-old female Qingyuan partridge chickens were randomly allocated to four treatment groups with six replicates of 40 birds each, and the feeding trial was lasted for 30 d. The controls were fed on a basal diet without in-feed antibiotics; the birds in the antibiotic group were fed the basal diet supplemented with 20 mg/kg virginiamycin; the remaining birds were fed the basal diet containing 150 or 300 mg/kg OEO, respectively. Dietary supplementation with 150 or 300 mg/kg OEO increased average daily feed intake (P = 0.057) and average daily gain (P < 0.05). The activities of glutathione peroxidase and total antioxidative capacity in plasma, jejuna, and ileal mucosa were increased by OEO supplementation (P < 0.05), with a trend of lower jejunal content of malonaldehyde (P = 0.062). Moreover, dietary OEO increased the content of secretory immunoglobulin A (P = 0.078) and the relative expression of Claudin 1, Mucin 2, and Avain beta-defensin 1 in ileum (P < 0.05). Sequencing data of 16S rRNA indicated that dietary OEO increased the relative abundance of Firmicutes phylum, and Clostridium and Lactobacillus genera, and decreasing that of Romboutsia. Functional analyses indicated that microbial amino sugar and nucleotide sugar metabolism, replication, and repair systems were higher in OEO groups than those of controls and antibiotic treatment. In conclusion, dietary supplementation with OEO enhanced growth performance, alleviated local oxidative stress in intestine, improved production of natural antibodies, and favorably modulated intestinal microbiota composition.     

Effects of Cultivars,Transplanting Patterns,Environment, and Their Interactions on Grain Quality of Japonica Rice

With the increasing scarcity of rural labor, the rice transplanting pattern is encountering a shift from artificial transplanting (AT) to mechanical transplanting (MT) in numerous rice‐growing districts of China. The shift of transplanting patterns combined with altered growing environment during the grain‐filling stage in different years presumably affects rice quality. Nevertheless, related information is currently limited. This study investigated the effects of cultivars, transplanting patterns, environment, and their interactions on appearance, milling, eating, and nutritional qualities of four japonica rice varieties. The significant interactive effects of cultivars, environment, and transplanting patterns on almost all rice quality parameters (except Thr, Met, and Ile) were observed. Cultivars and environment were the main factors influencing rice appearance and milling and eating qualities. Cultivar was the primary factor affecting rice nutritional quality. Among all treatments, environment showed the strongest effect on percentage of chalky kernel, milled rice yield, peak viscosity, breakdown, setback, consistence, amylose, Glu, Tyr, and Met contents. However, Leu and Phe contents were unaffected by environment but only by cultivars and transplanting patterns. In addition to amylose and protein, Glu and Met contents were also involved in determining rice eating quality. Amino acid contents (except Cys, Tyr, and Met) were significantly negatively correlated with head rice yield, showing the function of amino acids in controlling rice milling quality. Percentage of chalky kernel as well as protein and almost all amino acid contents were significantly negatively correlated with the difference of maximum and minimum temperature (DMMT) and positively correlated with relative humidity (RH), whereas head rice yield did it reversely. Amylose content and setback were significantly negatively related to daily maximum temperature (DMAT), daily minimum temperature (DMIT), daily average temperature (DAT), and effective temperature accumulation (ETA). However, peak viscosity, breakdown, and consistence had contrary performances. According to these results, we can infer that DMMT and RH are important environmental factors affecting rice appearance, milling qualities, and nutritional qualities and that DMAT, DMIT, DAT, and ETA are key environmental factors influencing rice eating quality.     

基于WSN的水环境监控系统设计

针对湿地水环境监控需求,采用CC2530芯片设计无线传感器网络终端节点,基于Z-Stack协议栈构建局域自组织无线网络,水体监测传感器的终端节点采集的数据最终汇聚到由CC2531和ARM构建的协调器上,经GPRS与远程上位机客户端建立通信链接并接入互联网络。该系统可以广泛应用于湿地等大范围环境监控,具有成本低、便于维护和节约人力资源等优点。     

通用型联合收割机独立割台液压传动系统设计

对比国内传统的单一型联合收割机及国外通用型互换割台式联合收割机,分析了通用型联合收割机独立割台液压传动系统及搅龙、割刀与拨禾轮的作业过程参数。以星光联合收割机为例,对独立割台液压传动系统的配置方案、液压元件的选型、液压系统主要参数的确定、液压系统的性能验算等方面进行了研究,为我国通用型联合收割机独立割台液压传动系统的设计和配置提供重要的参考价值。     

烟草田间起垄机作业适应性研究

对开沟式和盒式的1WG-6.3型自走式小型起垄机进行田间试验,并对其作业效益、作业效率及作业效果等指标进行测量及性能分析对比。结果表明:盒式起垄机每公顷平均油耗较低,作业效率较高,稳定性好,起垄效果较好,能满足烤烟种植起垄效果的农艺要求;开沟式起垄机能满足烤烟种植垄底宽、垄高的农艺要求,但不能满足烤烟种植垄基宽的农艺要求,且每公顷平均油耗较高,作业效率较低,稳定性较差,垄形一般。因此,盒式起垄机更能适应烟草田间起垄作业。