Potato evapotranspiration and yield under different drip irrigation regimes

A field experiment comparing different irrigation frequencies and soil matric potential thresholds on potato evapotranspiration (ET), yield (Y) and water-use efficiency (WUE) was carried out in a loam soil. The experiment included five treatments for soil matric potential: F1 (-15 kPa), F2 (-25 kPa), F3 (-35 kPa), F4 (-45 kPa) and F5 (-55 kPa) and six treatments for irrigation frequency: N1 (once every day), N2 (once every 2 days), N3 (once every 3 days), N4 (once every 4 days), N6 (once every 6 days) and N8 (once every 8 days). Results indicate that both soil matric potential and drip irrigation frequency influenced potato ET, Y and WUE. Potato ET increased as irrigation frequency and soil matric potential increased. Comparing soil water potential, the highest ET was 63.4 mm (32.1%) more than the lowest value. Based on irrigation frequency treatments, the highest ET was 36.7 mm (19.2%) more than the lowest value. Potato Y and WUE were also found to increase as irrigation frequency increased. Potato Y increased with an increase in soil water potential then started to decrease. The highest Y and WUE values were achieved with a soil matric potential threshold of -25 kPa and an irrigation frequency of once a day.Communicated by J. Ayars     

Mineralized,obstructive cardiac myxoma with chondroid differentiation in a cocker spaniel

A 12-year-old castrated male cocker spaniel dog was referred for evaluation of signs consistent with right-sided heart failure. Thoracic radiography revealed mineralization in the region of the right atrium. Echocardiography identified a mass partially filling the right atrium and right ventricle and obstructing flow through the right heart. These findings were confirmed at necropsy and histopathologic features were consistent with myxoma with chondroid differentiation.     

Influence of Salinity in the Bioavailability of Zn in Sediments of the Gulf of Cádiz (Spain)

This study assesses the effect of salinity in bioavailability and toxicity of Zn by means of laboratory bioassays by observing contamination in both sediment and water, accumulation of Zn in biological tissues, and histopathological damage in the gills and guts tissues of Ruditapes philippinarum clams, which were exposed to different types of sediments from the Gulf of Cádiz (SW Spain) as well as two dilutions of toxic mud coming from an accidental mining spill. With this objective, the coefficients of distribution (K _D) for Zn between overlying water and sediments were calculated, the histopathological frequencies in the tissues of the gills and guts of clams were determined, and the biota-sediment bioaccumulation factors as well as the bioaccumulation factors were quantified in the different stations. Results showed that the greatest histopathological damages appeared when the salinity values decreased. Statistical results showed that salinity was inversely correlated with histopathological damage (p?<?0.01) for the lesion index for gills. The most outstanding results were observed in the two dilutions of toxic mud (0.3% and 7.9%) at a salinity value of 10. Salinity was inversely correlated with the concentration of Zn in biological tissues (p?<?0.05) and inversely correlated with the concentration of Zn in water and sediment. Zn mobilization to the overlying water is produced when salinity values decrease.     

Biochar improves sediment microbial fuel cell performance in low conductivity freshwater sediment

Purpose

The low conductivity of sediments for mass and electron transport is the most severe limiting factor in sediment microbial fuel cells (SMFCs), so that sediment ameliorations yielded more remarkable effects than electrode improvements. The objective of this research was to enhance the electricity generation of SMFCs with amendments of biochar to freshwater sediments for conductivity enhancement.

Materials and methods

Laboratory-scale SMFCs were constructed and biochars were produced from coconut shells at different temperatures. Variations in the power output, electrode potential, internal resistance, total organic carbon (TOC) content, and microbial communities were measured.

Results and discussion

Amending with biochar reduced the charge transfer resistances of SMFCs and enriched the Firmicutes (mainly Fusibacter sp.) in the sediment, which improved the SMFC power generation by two- to tenfold and enhanced the TOC removal rate by 1.7- to fourfold relative to those without the amendment.

Conclusions

The results suggested that biochar amendment is a promising strategy to enhance SMFC power production, and the electrical conductivity of biochar should be considered important when interpreting the impact biochar has on the electrical performance of soil or freshwater sediment MFCs.

     

Nutrient limitations to bacterial and fungal growth during cellulose decomposition in tropical forest soils

Nutrients constrain the soil carbon cycle in tropical forests, but we lack knowledge on how these constraints vary within the soil microbial community. Here, we used in situ fertilization in a montane tropical forest and in two lowland tropical forests on contrasting soil types to test the principal hypothesis that there are different nutrient constraints to different groups of microorganisms during the decomposition of cellulose. We also tested the hypotheses that decomposers shift from nitrogen to phosphorus constraints from montane to lowland forests, respectively, and are further constrained by potassium and sodium deficiency in the western Amazon. Cellulose and nutrients (nitrogen, phosphorus, potassium, sodium, and combined) were added to soils in situ, and microbial growth on cellulose (phospholipid fatty acids and ergosterol) and respiration were measured. Microbial growth on cellulose after single nutrient additions was highest following nitrogen addition for fungi, suggesting nitrogen as the primary limiting nutrient for cellulose decomposition. This was observed at all sites, with no clear shift in nutrient constraints to decomposition between lowland and montane sites. We also observed positive respiration and fungal growth responses to sodium and potassium addition at one of the lowland sites. However, when phosphorus was added, and especially when added in combination with other nutrients, bacterial growth was highest, suggesting that bacteria out-compete fungi for nitrogen where phosphorus is abundant. In summary, nitrogen constrains fungal growth and cellulose decomposition in both lowland and montane tropical forest soils, but additional nutrients may also be of critical importance in determining the balance between fungal and bacterial decomposition of cellulose.     

Effects of formalin on total haemocytes count and histopathological changes in the shrimp Litopenaeus schmitti (Pérez‐Farfante & Kensley 1997)

Formalin is used in shrimp industry to eliminate ectoparasites and as a disinfectant. However, the effect of formalin on shrimp's defense mechanism is unknown. Several biomarkers were used to assess the immune response of juveniles of the shrimp Litopenaeus schmitti exposed to different concentrations of formalin (10, 25 and 50 mg L^?1) during 24 and 48 h. Formalin concentrations of 25 and 50 mg L^?1 produced a significant reduction in the total haemocyte count at both 24 and 48 h. Peroxidase and phenoloxidase activity did not show variations. The total protein concentration in haemolymph of shrimps was not significantly different between experimental groups. Histological analysis showed hyperplasia in the gills of animals exposed at 10 mg L^?1 for 24 h; however, the exposure at 25 and 50 mg L^?1 caused necrosis in gills, hepathopancreas and the antennal gland.     

杂交水稻夷优180的选育与应用

夷优180系福建省南平市农业科学研究所用自主选育的三系不育系夷A与恢复系南恢180配组而成的杂交中稻新品种。经多年在福建省各地试验、试种表现群体整齐、适应性广、产量高、抗性好等特点,2014年通过福建省农作物品种审定。简述了杂交水稻夷优180的选育及应用。     

中稻大田机插与手工插秧简比试验

水稻机械化插秧能够大幅度提高劳动生产率,减轻劳动强度,降低生产成本,达到增产增收的效果。试验结果表明:水稻机插栽培有效穗数多,有利于形成较为合理的群体结构,从而穗粒数较多,结实率提高,产量高,增产效果明显。     

海水倒灌农田水稻栽培技术示范小结

通过对2014年"威马逊"超强台风造成海水倒灌农田后的修复改良水稻栽培技术,包括品种筛选、整地、育秧、水肥管理等试验。摸索出一套海水倒灌农田的水稻高产栽培技术,解决了海水倒灌农田灾区农民的口粮问题,为今后海南沿海地区台风造成海水倒灌农田后的水稻恢复生产储备相应技术。     

福建北部山区中稻浸种催芽技术

介绍了闽北山区水稻生产的现状,种子发芽基本条件,中稻浸种催芽技术及种子催芽过程中常见问题及解决办法。