Rainwater harvesting for the management of agricultural droughts in arid and semi-arid regions

Human activities, which affect ecosystem dynamics, pose a continuous challenge to individuals and communities trying to survive in arid and semi-arid regions. The development of a method to employ rainwater harvesting (RWH) in the management of agricultural drought in arid and semi-arid regions comprised two phases: (i) detection of agricultural drought in Egypt’s El-Beheira governorate using a normalized difference vegetation index differencing technique and (ii) the delineation of RWH locations potentially suitable for the management of agricultural drought in the region using a GIS decision support system (DSS). Temporal vegetation cover analysis showed significant spatio-temporal changes that have occurred in the last 40 years: a general decrease in vegetation cover reflecting a trend towards ecosystem degradation, contrasted by a greening trend in some pockets within the region. Potentially suitable rainwater harvesting areas for agricultural drought management and attendant vegetation recovery were delineated in the region using DSS. The model generated a RWH map with five categories of suitability: excellent, good, moderate, poor and unsuitable. On average, 10.9 % (1104.17 km²) and 12 % (1215 km²) of the study area was classified as excellent and good for RWH, respectively, while 11.7 % (1185.21 km²), 15.4 % (1560 km²) and 50 % (5065 km²) of the area were classified as moderate, unsuitable and poor, respectively. Most of the areas with excellent to good suitability predominantly lie in areas which faced severe drought between 2010 and 2014. To successfully implement the drought management plan, a number of RWH sites within the excellent areas must be developed.     

Enriched Artemia with L-lysine and DL-methionine on growth performance,stress resistance,and fatty acid profile of Litopenaeus vannamei postlarvae

A 15-day study was conducted to evaluate the effect of enrichment of Artemia metanauplii with four different emulsions, including: (A) Easy-DHA Selco; (B) Easy-DHA Selco + L-lysine (4 g/L); (C) Easy-DHA Selco + DL-methionine (4 g/L); and (D) Easy-DHA Selco + L-lysine (2 g/L) + DL-methionine (2 g/L) on growth and stress resistance of white leg shrimp Litopenaeus vannamei larvae (from Mysis I to postlarvae12). It is noticed that shrimp PL in group B had the highest wet (36.1 ± 3.1 mg) and dry (1116.7 ± 60.0 µg) weights as well as stress resistance to fresh water (64.0 ± 5.5%).     

Supplementation of diets for Oreochromis niloticus with essential oil extracts from lemongrass (Cymbopogon citratus) and geranium (Pelargonium graveolens) and effects on growth,intestinal microbiota,antioxidant and immune activities

This study aimed to investigate the effects of dietary supplementation of lemongrass (Cymbopogon citratus) (LEO) and geranium (Pelargonium graveolens) (GEO) essential oils on growth, immunity, antioxidant responses and disease resistance of Oreochromis niloticus. Fish (3.04 ± 0.003 g) were fed the basal diet (G₁), or the basal diet supplemented with LEO at 200 and 400 mg kg^?1 of the diet (G₂ and G₃), or GEO at 200 and 400 mg kg^?1 of the diet (G₄ and G₅), respectively for 12 weeks. Growth indices and feed utilization were significantly improved with G₂, G₃ and G₅ groups. Also, a significant increase in protein content of the whole body was recorded in all groups. G₂ and G₅ showed a significant rise of both catalase activity and reduced glutathione content with a significant incline in the MDA level. Lysozyme activity and total IgM levels were significantly increased in G₂ and G₅ groups. G₃ and G₅ groups had a significantly lower intestinal total bacteria, Coliforms, Escherichia coli and Aeromonas spp counts. Following challenge with A. hydrophila, all groups had a high survival rate. In conclusion, LEO and GEO could be a candidate dietary supplementation in fish improving growth performance, feed utilization, oxidative status, immune responses and disease resistance.     

森林生态蓄水功能的经济评价(个案研究:伊朗扎格罗斯森林)(英文)

森林生态服务直接或间接地造福人类。本文利用模拟模型和地理信息系统作为工具,分析生态因子对生态系统服务功能的作用,评估了伊朗西部扎格罗斯森林对Bazoft河流域水源保护的经济价值。应用HEC-HMS模型中的曲线数字法对降雨量-径流进行了模拟。该模型需要输入土地覆被、土壤、短期降雨和流出数据。用观测数据并分阶段校对对拟合模型的功效进行了修订。测定了森林在4种设定的土地覆盖方案中保水性和减少地表径流量的作用以及土地用途改变对该区降雨量-径流行为的影响。结果表明:方案一假定该流域全被森林覆盖,总的流出量将最小,降雨初期损失将增加。用重置成本法估算了森林水文功能之保水性经济价值。评估结果表明,每公顷Bazoft河流域的森林可以蓄存84.8立方米水,年产值0.5 US$/m3。因此,每公顷BazoR河流域的森林保水性经济评价值是43US$。说明覆被森林有利于该流域经济发展,该研究有助于决策者选择适当的、经济可行的发展策略。     

Effect of botanical insecticide Nimbecidine<Superscript>®</Superscript> on food consumption and egg hatchability of the terrestrial snail <Emphasis Type="Italic">Monacha obstructa</Emphasis>

In the laboratory, a commercial neem-based insecticide—Nimbecidine^®—was evaluated as a potential pest management tool for the terrestrial snail, Monacha obstructa (Pfeiffer, 1842) (Hygromiidae). Effects of different concentrations of the botanical insecticide on food consumption and egg hatchability of the terrestrial snail were studied. Generally, food consumption of immature and adult snails decreased as the concentrations of Nimbecidine^® increased. At the highest concentration (10 ml/l), the snails avoided contacting with food completely. The food intake of immature individuals was significantly (p < 0.05) more affected by the Nimbecidine^® treatment (at 1.25 ml/l) than that of adults. LC₅₀ of Nimbecidine^® for the treated eggs was 2.18 ml/l, and eggs failed to hatch at concentration of 10 ml/l. Nimbecidine^® showed sufficient biological activity against the food consumption and eggs viability of M. obstructa, thus the preparation has a potential to protect field crops from this pest snails.     

Comparative therapeutic effect of steroidal and non-steroidal anti-inflammatory drugs on pro-inflammatory cytokine production in water buffalo calves (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) naturally infected with bronchopneumonia: a randomized clinical trial

In the current study, we compared the therapeutic effects of a non-steroidal and a steroidal anti-inflammatory drug on the production of pro-inflammatory cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-12p40 (IL-12p40), interferon gamma (IFNγ), and tumor necrosis factor alpha (TNF-α) in the blood of water buffalo (Bubalus bubalis) calves naturally infected by bronchopneumonia. Twenty-seven buffalo calves (7 ± 2-month-old, 163 ± 12 kg) reared in smallholder farms in El-Dakahlia province in Egypt were identified to have bronchopneumonia and randomly allocated into three equal groups. Ten clinically healthy buffalo calves with negative bronchoalveolar lavage results were served as negative control. Diseased calves were treated with tulathromycin alone, a combination of tulathromycin with dexamethasone (steroidal anti-inflammatory drug) or tulathromycin with flunixin meglumine (non-steroidal anti-inflammatory drug). The results revealed significant elevations (P < 0.05) in the production of selected cytokines in all diseased calves in comparison with healthy animals. Six days post-treatment, a significant inhibition (P < 0.05) in the production of all assessed cytokines was observed in the blood of all treated calves. Interestingly, the serum concentrations of IL-1β and IL-12p40 were returned to the normal levels in pneumonic calves treated with the combination therapy of tulathromycin and flunixin meglumine. A strong significant positive correlation (P < 0.05) was detected between clinical sum scoring and IL-12p40 and TNF-α concentrations. The obtained results indicate the selectively potent anti-inflammatory effect of flunixin meglumine on the production of pro-inflammatory cytokines in pneumonic buffalo calves and highlight the efficacy of flunixin meglumine in the treatment of bronchopneumonia in buffalo calves when used in combination with tulathromycin.     

Effects of conocarpus biochar on hydraulic properties of calcareous sandy soil: influence of particle size and application depth

A laboratory column experiment was conducted to investigate the effects of 400°C biochar at application rate of 15 g kg^?1 (21.9 t ha^?1) with different particle sizes (<0.5 mm (S₁), 0.5–1 mm (S₂) and 1–2 mm (S₃)) and application depths (0–2 cm depth (D₀), 4–6 cm depth (D₅) and 8–10 cm depth (D₁₀)) on hydro-physical properties of sandy loam soil. The results indicated that applying biochar decreased the waterfront and saturated hydraulic conductivity of sandy loam soil. The cumulative evaporation was the highest and amounted to 40.9 mm in the non-treated soil, but it recorded the lowest amount of 32.2–35.5 mm in the biochar-treated soil. Applying biochar caused significant increases in the amount of conserved and retained water with the highest amount of water conserved in soil treated with S₂ biochar at D₅. Moreover, the cumulative water infiltration through the soil was significantly reduced by S₁ and S₂ biochars at D₀. The values of saturated hydraulic conductivity for biochar treatments were significantly lower than those for the control, with the lowest values for S₁ at D₀ and D₅. These results suggest positive improvement for the hydro-properties of coarse-textured soils following biochar addition, especially with finer particles of biochar.     

Interactive effects of biochar and polyacrylamide on decomposition of maize rhizodeposits: implications from <Superscript>14</Superscript>C labeling and microbial metabolic quotient

Purpose

The applications of biochar (BC) and polyacrylamide (PAM) may have interactive effects on carbon (C) dynamics and sequestration for improving the soil quality and achieving sustainable agriculture. Relative to BC and PAM, rhizodeposits act as C and energy source for microorganisms and may change the mineralization dynamics of soil organic matter (SOM). No attempt has been made to assess the effects of BC, anionic PAM, or their combination on the decomposition of different aged ¹⁴C-labeled rhizodeposits. The objective of this study was to investigate the effects of the treatments mentioned above on the decomposition of different aged ¹⁴C-labeled maize rhizodeposits.

Materials and methods

biochar (BC) at 10 Mg ha^?1 or anionic PAM at 80 kg ha^?1 or their combination (BC + PAM) was applied to soils with/without 2-, 4-, 8-, and 16-day-aged ¹⁴C-labeled maize rhizodeposits. After that, the soil was incubated at 22 °C for 46 days.

Results and discussion

After 2 days of incubation, the total CO₂ efflux rates from the soil with rhizodeposits were 1.4–1.8 times higher than those from the soil without rhizodeposits. The cumulative ¹⁴CO₂ efflux (32 % of the ¹⁴C input) was maximal for the soil containing 2-day-aged ¹⁴C-labeled rhizodeposits. Consequently, 2-day-aged rhizodeposits were more easily and rapidly decomposed than the older rhizodeposits. However, no differences in the total respired ¹⁴CO₂ from rhizodeposits were observed at the end of the incubation. Incorporation of ¹⁴C into microbial biomass and 66–85 % of the ¹⁴C input remained in the soil after 46 days indicated that neither the age of ¹⁴C-labeled rhizodeposits nor BC, PAM, or BC + PAM changed microbial utilization of rhizodeposits.

Conclusions

Applying BC or BC + PAM to soil exerted only minor effects on the decomposition of rhizodeposits. The contribution of rhizodeposits to CO₂ efflux from soil and MBC depends on their age as young rhizodeposits contain more labile C, which is easily available for microbial uptake and utilization.