Proposal for equitable water allocation for rotational irrigation in Pakistan

A rotational water supply system is designed to deliver a constant flow of water among irrigators along a tertiary canal. Under the existing rotational system in Pakistan transmission losses along the canal are not considered. A constant time per unit irrigated area is allocated to all the farmers regardless of their location along the canal. This results in decreasing volumes of water delivered to downstream farmers. A variable time model is developed which allocates more time to the downstream farmers to deliver a constant volume of water per unit area to all the farmers in the command area of a tertiary unit.     

Analysis of groundwater behaviour in a farmer controlled subsurface tile drainage system in Mardan, Pakistan

Extensive subsurface drainage system was installed in districtMardan in the North West Frontier Provinceof Pakistan in 1987 to control increasingwater logging and salinity problems due tocanal irrigation. Several recentlycompleted fields studies have indicatedthat subsurface drainage system hasenormously lowered watertable in certainareas due to extensive drainage network. Therefore, a study of controlled subsurfacedrainage technique was initiated in MardanScarp area to observe the temporal andspatial variations in water table depths ofthis specific case under various modes ofcanal irrigation and monsoon rains. Twoartificially drained areas, consisting of40 ha and 160 ha respectively, werecontrolled and selected for extensivemonitoring. A total of 98 observationswells (7.6 cm dia. and 4.1 m depth) wereinstalled in between lateral drains toobserve water table fluctuation. Theresults of this study are very interesting.Each of the two areas monitored in thestudy behaved differently. It was observedthat in one of the areas design water tabledepth at 1.1 m was maintained with properfunctioning of the controlled techniqueapplied to the subsurface drainage system. The results from this area showed that 25to 55% of the time throughout the yearachieved this objective whereas in thesecond area desired water table could notbe maintained and water table depth in thisarea remained between 2.0 to 2.7 m causingunnecessary water stress to plants. Alsoit was observed that watertable in theformer area is mostly controlled by thefunctional behavior of the irrigationcanal. In addition, the proper functioningof controlled techniques in subsurfacedrainage system supplemented veryefficiently to retain the groundwater levelto the optimal limits in dry season and tothe design ones in the others for timelyneeds of the crops. Also rainfalls havesignificant impact on the spatial andtemporal behaviors of water table depths inboth the areas during the monsoon season.     

Serological survey of Babesia bovis and Babesia bigemina in cattle in South Africa

A total of 719 serum samples collected from clinically healthy cattle from eight provinces located in different districts of South Africa were examined by the indirect enzyme-linked immunosorbent assay (ELISA) and the standard indirect fluorescent antibody test (IFAT) to determine the serological prevalence of Babesia bovis and Babesia bigemina. The results showed that 35.3% and 39.7% of cattle were positive for B. bovis and 30% and 36.5% were positive for B. bigemina antibodies on ELISA and IFAT, respectively. Mixed infections were detected in 18.2% and 26.3% of the samples using ELISA and IFAT, respectively. Consequently, the ELISAs with recombinant B. bovis spherical body protein-4 (BbSBP-4) and B. bigemina C-terminal rhoptry-associated protein-1 (BbigRAP-1/CT) were proven to be highly reliable in the serological diagnoses of bovine babesiosis in South African cattle, as evidenced by the significant concordance rates when the results were compared to those of IFAT. Moreover, the serological prevalence was significantly different among the tested provinces, in which the ranges exhibited between 15% and 73% for B. bovis infection and between 13% and 54% for B. bigemina infection. High sero-positive rates were present in Mpumalanga and KwaZulu-Natal provinces, while the lowest rate was in the North West province. Our data provide important information regarding the current seroprevalence of bovine babesiosis in South Africa, which might be beneficial in developing rational strategies for disease control and management.     

Dicyandiamide increases the fertilizer N loss from an alkaline calcareous soil treated with <Superscript>15</Superscript>N-labelled urea under warm climate and under different crops

Using an alkaline calcareous soil, experiments were conducted to elucidate the effects of nitrification inhibitor dicyandiamide (DCD) on the fate of ¹⁵N-labelled urea applied to cotton, maize, and wheat under greenhouse conditions. Combined effects of DCD and two levels of wheat straw (applied to cotton) and of fertilizer application method (conventional broadcast vs. point injection in maize and wheat) on the recovery of the fertilizer N were also studied. High soil temperatures prevailed under cotton and maize, whereas the soil temperature was relatively moderate during the wheat growing season. The fertilizer N loss under cotton was lowest (44% of the applied) when urea was applied alone; the loss increased due to DCD (54%) or wheat straw (50–54%) and was highest (63–64%) when DCD and wheat straw were applied together. Under maize also, DCD increased the loss of the fertilizer N applied by the conventional method (51% without DCD vs. 66% with DCD) or by point injection (26% without DCD vs. 42% with DCD). With the conventional method under wheat, DCD had no effect on the fertilizer N loss (34–37% of the applied). The fertilizer N loss under wheat was least (16%) when urea solution was point-injected but increased (24–26%) due to DCD or/and when pH of the urea solution was reduced to 2. Besides, DCD significantly reduced the fertilizer N uptake and increased the fertilizer N immobilization in soil under cotton and maize. However, DCD applied in combination with a higher level of wheat straw significantly increased the cotton dry matter and N yields due to increased N availability from sources other than the fertilizer. The results suggested that the use of DCD may not be beneficial in alkaline calcareous soils and that point injection of urea solution without any amendment is more effective in conserving the fertilizer N as compared to the conventional broadcast method.     

Structure and physical properties of starch/poly vinyl alcohol/sodium montmorillonite nanocomposite films

Nanocomposites of starch, poly vinyl alcohol (PVOH), and sodium montmorillonite (Na(+)MMT) were produced by solution mixing and cast into films. Tensile strength (TS) and elongation at the break (E%) of the films ranged from 11.60 to 22.35 MPa and 28.93-211.40%, respectively, while water vapor permeability (WVP) ranged from 0.718 to 1.430 g·mm/kPa·h·m(2). In general, an increase in Na(+)MMT content (0-20%) enhanced TS and decreased E% and WVP. Use of higher molecular weight PVOH increased both TS and E% and also decreased WVP. Mechanical properties were negatively affected, but water vapor barrier properties improved with increasing starch content (0-80%). X-ray diffraction and transmission electron microscopy were used to analyze the nanostructure, and molecular conformations and interactions in the multicomponent nanocomposites were inferred from glass transition behavior. Interactions between starch and PVOH were strongest, followed by polymer/clay interactions. On the basis of this insight, a conceptual model was presented to explain the phenomena of intercalation and exfoliation in the starch/PVOH/Na(+)MMT nanocomposites.     

Cucumber performance is improved by inoculation with plant growth-promoting microorganisms

We investigated the effects of inoculation of Rhodobacter sphaeroides, Lactobacillus plantarum, and Saccharomyces cerevisiae on cucumber plant growth promotion and on the contents of plant hormones, amino acids, and mineral nutrients. We showed that treatment with all three bio-inoculants significantly increased the shoot length, root length, shoot fresh weight, shoot dry weight, and chlorophyll content, via secretion of indole acetic acid and/or organic acids. Inoculation with R. sphaeroides had more favorable effect on plant growth than did inoculation with L. plantarum or S. cerevisiae, by significantly enhancing the gibberellin and reducing the abscisic acid contents. The results of amino acid analysis revealed that inoculation with R. sphaeroides, L. plantarum, and S. cerevisiae generally increased the contents of 17 amino acids, namely, aspartic acid, threonine, serine, glutamic acid, glycine, alanine, cysteine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine, arginine, and proline. With the exception of cysteine, all these amino acids were present in higher concentrations in plants inoculated with R. sphaeroides than in control plants or in plants inoculated with L. plantarum and S. cerevisiae. Furthermore, inoculation with R. sphaeroides significantly increased the calcium, potassium, magnesium, and phosphate contents. Our results suggest that the use of R. sphaeroides, L. plantarum, and S. cerevisiae in agricultural fields can improve plant growth. Moreover, inoculation of cucumber plants with R. sphaeroides regulates plant functional metabolites, thereby promoting plant growth.     

Suppression of superphosphate-phosphorus fixation by farmyard manure I. High phosphorus uptake from superphosphate

Pot and field experiments were conducted on alkaline calcareous soils of Pakistan to determine the effect of premixing superphosphate (SUP) with farmyard manure (FYM) on the fraction of plant phosphorus derived from the ³⁰P labelled SUP (y value). Premixing (SUP with FYM) before their addition to soil, markedly increased the uptake of SUP-P by plants. The premixed treatment also increased crop yield on phosphorus deficient soli. Optimum quantity of FYM required was twice that of SUP. Higher quantities of FYM had no additional effect on phosphorus availability from SUP.

The possible mechanism of this effect and the implications of these observations in phosphorus nutrition of plants have been discussed.     

Increased ammonification,nitrogenase, soil respiration and microbial biomass N in the rhizosphere of rice plants inoculated with rhizobacteria

Azospirillum brasilense and Pseudomonas fluorescens are well-known plant growth promoting rhizobacteria. However, the effects of A. brasilense and P. fluorescens on the N cycles in the paddy field and rice plant growth are little known. This study investigated whether and how A. brasilense and P. fluorescens contribute to the N transformations and N supply capacities in the rhizosphere, and clarified the effects of A. brasilense and P. fluorescens on the N application rate in rice cultivation. Inoculations with A. brasilense and P. fluorescens coupled with N application rate trials were conducted in the paddy field in 2016 and 2017. The inoculations of rice seedlings included four treatments: sterile saline solution(M_0), A. brasilense(Mb), P. fluorescens(Mp), and co-inoculation with a mixture of A. brasilense and P. fluorescens(Mbp). The N application rate included four levels: 0 kg N ha~(–1)(N_0), 90 kg N ha~(–1)(N_(90)), 180 kg N ha~(–1)(N_(180)), and 270 kg N ha~(–1)(N_(270)). The results indicated that the Mbp and Mp treatments significantly enhanced the ammonification activities in the rhizosphere compared with the M_0 treatment, especially for higher N applications, while the Mbp and Mb treatments greatly enhanced the nitrogenase activities in the rhizosphere compared with the M_0 treatments, especially for lower N applications. Azospirillum brasilense and P. fluorescens did not participate in the nitrification processes or the denitrification processes in the soil. The soil respiration rate and microbial biomass N were greatly affected by the interactions between the rhizobacteria inoculations and the N fertilizer applications. In the Mbp treatment, N supply capacities and rice grain yields showed no significant differences among the N_(90), N_(180), and N_(270) applications. The N application rate in the study region can be reduced to 90 kg N ha~(–1) for rice seedlings co-inoculated with a mixture of A. brasilense and P. fluorescens.     

Investigation of equine influenza virus in two geographical regions of Pakistan

Purpose

The present study was an attempt to elucidate the seroprevalence of equine influenza virus (H3N8) in two geographically distinct regions of Pakistan where vaccination is not routinely practiced.

Methods

A total number of 315 animals of family Equidae were included in the survey. Blood samples and nasal swabs were collected from the same animal and analyzed through ELISA and Hemagglutination Inhibition.

Results

The seroprevalence for EIV was 10 and 8.39 in districts under study. Out of 29 ELISA positive sera, 7 (24.1 %) showed antibodies against H1 and 22 (75.9 %) showed against H3 of influenza strains. Specie-wise antibody titer against H1 was 7.5 and 9.0 for horses and donkeys, respectively, while mules were negative. Similarly, antibody titer against H3 was 7.12, 6.9, and 6.0 for horses, donkeys, and mules, respectively. No strain was isolated from the nasal swabs despite very high antibody titers of H1 and H3 in the sera of the same animals.

Conclusions

Influenza viruses are circulating in equine species and continuous surveillance is needed to keep check on any future outbreak.     

Effects of salicylic acid on growth and accumulation of phenolics in Zea mays L. under drought stress

The accumulation of total soluble and cell wall-bound phenolics and total soluble proteins in Zea mays plants exposed to drought stress and foliar spray of salicylic acid (SA) at 10^?4?mol/L and 10^?5?mol/L was investigated. Drought stress was imposed at the four-leaf stage for 10 days (30–35% field capacity). Dehydration of maize leaves was accompanied by the accumulation of both total soluble and cell wall-bound phenolics, reduction in leaf relative water content (LRWC), and shoot and root growth attributes. Foliar spraying of SA further augmented the content of total soluble and cell wall-bound phenolics and total soluble proteins content under drought stress. SA ameliorated the adverse effects of drought stress on LRWC, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, root length and root area. The accumulation of both soluble and cell wall-bound phenolics by foliar spray of SA may be a mechanism related to SA-induced drought stress tolerance in maize. It was concluded that foliar spraying of SA at 10^?5?mol/L can be highly economical and effective for modifying the effects of drought stress on maize at the four-leaf stage.