基于电容式湿度传感器的植物粉料含水率测量

提出了一种基于电容式湿度传感器的植物粉料含水率测量方法。由电容式湿度传感器和数据采集卡组成的测量系统获取植物粉料含水率数据,应用一阶差分法剔除奇异值后,通过惯性滤波法处理数据。由菊花粉含水率的13个测量值与烘干法测得的真值对比试验结果可知,测量值与真值之间的最大相对误差为1.61%,平均相对误差为0.76%,均小于5%(测量样品数为5时置信区间为95%),表明该方法能够用于测量低水分植物粉料的含水率。     

猴头菌不同生长发育期粗蛋白、粗多糖含量及水溶性粗多糖体外免疫活性

测定猴头菌(Hericium erinaceus)华中猴头菌株不同生长发育期子实体中的粗蛋白、粗多糖和水溶性粗多糖中β-葡聚糖含量,并研究不同生长发育期子实体粗多糖体外刺激巨噬细胞产生NO的活性变化规律.结果表明,供试菌株不同生长发育期子实体的粗蛋白、粗多糖和β-葡聚糖含量以及粗多糖体外刺激巨噬细胞产生NO的活性均存在显著或极显著差异,随着生长发育的进行,猴头菌子实体中粗蛋白含量总体上呈下降的趋势(小菌剌期比前一时期有所增加),而多糖含量则总体呈上升趋势(小菌刺期比后一时期高),β-葡聚糖含量呈先快速上升后平稳的趋势;分裂期粗多糖在浓度500 μg/mL时对RAW264.7释放NO的促进作用较强.     

绿地精准灌溉控制系统设计与最优灌溉量分析

为了提高绿地精准灌溉控制系统中两点法测量土壤墒情的测量精度,通过对土壤水分传感器一体化的研究,设计了双层复合土壤水分传感器,相比于传统的两个传感器策略,使用该复合型土壤水分传感器测量结果更加精确,且降低了能耗。为了获得绿地作物的最优灌溉量,确保灌溉水不浪费且能满足作物正常生长的需求,以高羊茅为例,通过实验,在综合分析高羊茅生长需求、土壤墒情和部分气象资料的基础上,得出适合于高羊茅的最优灌溉量为12 mm。     

Variability and Correlation between Exchangeable Sodium Percentage and Sodium Adsorption Ratio in Vertisols of Sudan

Vertisols in the Sudan occur under different climatic zones, ranging from arid in the north to tropical monsoon in the south, with rainfall varying from 150 mm to 1000 mm per annum. In this study, the exchangeable sodium percentage (ESP) was estimated from the sodium adsorption ratio (SAR); values of SAR and ESP for all identified soil series of Vertisols in the Sudan were extracted from the available data. These data were used to examine the variability in SAR and ESP in these soils using coefficient of variation (CV) as an index and then to regress ESP on SAR for the three master horizons (A, AC, C) and pooled data for all horizon. Curvilinear, linear, quadratic, and cubic equations were used to examine the relation between ESP and SAR. The significance of the F ratio and correlation coefficient was tested for individual equation. The soil series were then sorted out into saline and nonsaline, sodic and nonsodic, and the ESP was regressed on SAR once again. The equations used for the regression were curvilinear and first‐, second‐, and third‐degree polynomial equations. Then analysis of variance (ANOVA) was used to screen any significant difference between the estimated values of ESP (using these equations and USDA salinity laboratory equation) on one hand and the actual (measured) values of ESP. The results revealed that ESP and SAR are highly variable irrespective of depth despite slight decrease with depth. Furthermore, ESP is more variable than SAR in horizons A and AC but less variable in horizon C. The regression equations indicated that ESP might be reasonably estimated from SAR. However, different equations were appropriate for different horizons. Moreover, the result indicated that in most of the cases the relation between ESP and SAR better fits quadratic equations. But for simplicity, linear equations for all horizons could be used to estimate ESP from SAR.     

Preparation and Study of a Novel,Environmentally Friendly Seed-Coating Agent for Wheat

Traditional seed-coating agents are widespread and used in crop protection. However, the coatings can pose an environmental and health hazard. In this study, a novel wheat seed-coating agent was prepared by using natural polysaccharide as the main raw material, which produces bacteriostatic activity and enhances the germination and quality of seeds. The optimum formula of this seed-coating agent was ultimately determined through a series of laboratory experiments and field trials. The results showed that the yield of wheat seeds treated with this novel seed-coating agent was increased by 10% and its material cost was decreased by 15% compared with the conventional toxic seed-coating agent. The toxicity of the novel seed-coating agent was also less than that of the traditional one. Therefore, this wheat seed-coating agent had obvious economic and environmental benefits.     

Impact of Variable Potassium on Metabolism,Oil, and Seed Quality of Groundnut

To study the impact of variable potassium (K) on biomass, economic yield, and role of K in groundnut (Arachis hypogeae L.) metabolism, plants were grown in refined sand at different levels of K, ranging from 0.5 to 16 mM. The concentration of K increased with increase in supply in all parts of groundnut. Both low (<4 mM) and excess (>4 mM) K increased the activity of peroxidase, ATPase, and acid phosphatase and decreased the concentration of chlorophyll in leaves significantly. Low (<4 mM) and excess (>4 mM) concentrations of K inhibited pod and kernel (seed) formation in groundnut. Potassium stress (both low and excess) deteriorated the quality of groundnut seed by decreasing the concentrations of starch, protein, and oil and increasing that of sugars in seeds. The activities of certain enzymes also altered in K stress in leaves and seeds of groundnut.     

Response of rice to sulphur application under upland conditions

Abstract

A greenhouse experiment was carried out to determine the S response and the plant S content of rice (Oryza sativa L.) cultivars OS‐6 and IR‐20 grown in sandy Apomu soil series under upland conditions.

Sulphur application increased growth and dry matter yield. At low S rates OS‐6 gave higher grain yield than IR‐20. With high S rates, OS‐6 responded more in straw production. The leaf S content was highest during early growth and decreased with plant age. At flower emergence, the blade of the Y‐leaf appeared to be a suitable index for measuring the S status of the plant. The critical S level was estimated at 0.15%. The critical S levels in the grain and straw at harvest were estimated respectively at 0.12%, and 0.10%. The N/S ratios for the grain and straw at harvest appeared not to be a useful index for determining the critical S status of the plant.     

Content and distribution of lithium in La Pampa soils (Argentina)

Abstract

Extractable li with ammonium acetate was determined by flamephotometry, in normal soils, alkaline soils and saline soils in the Province of La Pampa (Argentina).

The soils were originated from differents parent material, with various rainfalls (arid to subhumid climate) and management.

The higher contents were found in saline soils. In the other soils the extractable lithium content depends on the parent material, but not on rainfall.

Different patterns of vertical and horizontal distribution of extractable lithium were found.

The origin of extractable lithium is here discussed.     

Nitrate and bromide contents of glasshouse radish as affected by soil content and global radiation

Abstract

Samples (208) of radish (Raphanus sativus L.) foliage and root were collected from commercial glasshouses. Simultaneously corresponding soil samples were taken. Both plant and soil samples were analysed for nitrate and bromide.

The nitrate contents of foliage and root are affected by global radiation and by nitrate content of the soil. An interaction between the two factors was found; It indicated that soil nitrate content had a considerable effect in summer, but much less so in winter under poor light conditions, when the level of nitrate in the crop is high regardless of the nitrogen status of the soil. To study the effect of radiation on nitrate content of radish in summer it was found best to consider the cumulative amount of radiation during 10 days before harvest; in winter, a period of 20–30 days was more suitable.

The bromide content of foliage and root (highest values being resp. 390 and 73 mg Br per kg fresh product) was correlated with the concentration of bromide in the 1:2 volume soil extract. An increase of 1 mmol NO₃ per 1 soil extract lowered the Br content of fresh radish roots by 5.8 mg Br per kg.     

滴灌控制土壤基质势对土壤水分分布和苜蓿生长的影响

采用在滴头正下20 cm深度处埋设负压计,分别设置-15、-25和-35 k Pa的土壤基质势控制滴灌,通过田间试验,研究了不同土壤基质势下土壤水分变化特点和紫花苜蓿的生长特性,分析了蒸发、降雨和灌水与土壤基质势之间的关系。从土壤剖面水分分布来看,整个生育期内-15 k Pa处理下的土壤剖面含水率整体集中在14%~15%,较-25和-35 k Pa处理的更为均匀,水分密集区域距离滴头最近;-15 k Pa处理下苜蓿株高达到41.7 cm,盖度为15.3%,生物量值达到了281.29 g/m~2,在所有处理中均为最高。