The variation of phosphorous content,grain yield,and rhizosphere microbial biomass among durum wheat cultivars under salinity stress

ABSTRACT

The effectiveness of plant–soil synergies is largely modulated by interaction between cultivar and rhizosphere microbiome. We evaluated the agronomic performance of six durum wheat cultivars, in two semi-arid locations in Tunisia that differed in their irrigation water salinity: S1 (6 dS m^?1) and S2 (12 dS m^?1). The two-consecutive-year field experiments assessed the effects of the microbial biomass carbon (MBC), leaf phosphorus (LP) and rhizosphere phosphorus (P) on the grain yield (GY) and yield components at tillering and flowering stages. Overall, in saline conditions, cultivars differed in above- and below-ground traits, particularly, with tolerant cultivars presenting relatively greater MBC, P and LP. Furthermore, in S2, GY positively correlated with MBC (r = 0.69), LP (r = 0.80) and P (r = 0.79). Additionally, in S2, MBC positively correlated with P (r = 0.87) and LP (r = 0.85) at flowering. This result was further confirmed by multiple linear regression (step-wise) analysis, which revealed that MBC and LP were the determinant components of GY variability under S2. The present study demonstrates that LP and soil P are mandatory for improving the management of durum wheat. Salinity tolerance was largely affected by the cultivars’ rhizosphere MBC.     

Evaluation of infant formula protein quality: comparison of in vitro with in vivo methods

Two-week protein efficiency ratio (2-wk PER), net protein ratio (NPR), calculated-protein efficiency ratio (C-PER), and discriminant computed-protein efficiency ratio (DC-PER) of milk- and soy-based infant formulas were compared to a 4-week protein efficiency ratio (PER). Expressed relative to ANRC casein, 2-week PER and NPR correlated significantly (P less than 0.01, r = 0.90) with PER. Although C-PER and DC-PER also correlated significantly (P less than 0.01) with PER, r = 0.71 and r = 0.87, respectively, these in vitro methods did not distinguish differences in protein quality among soy-based infant formulas. C-PER and DC-PER, as currently designed, are not applicable to the measurement of protein quality for all types of infant formulas.     

Diversity in reproductive characteristics of potato landraces and cultivars for producing true seed

Potato production from true seed, or true potato seed (TPS) is not a new system for this vegetatively propagated crop. Andean farmers have grown potatoes in the cool highlands from true seed for many centuries. TPS appears today as a promising technology in the warm tropics, where diseases impede the production of pathogen-free potato propagules. However, the identification of suitable genetic resources for potato seed production requires the selection of clones that lack antagonism between tuber growth and seed embryo development. Furthermore, the potential TPS parents need to possess characteristics of a sexually propagated crop that is grown for the harvest of its vegetative part, i.e., the tuber. This new process of domestication requires a change in the selection methods, which starts by assessing the potential of available potato clones for both reproductive characteristics and agronomic traits, particularly those of the tuber. Tetraploid landraces and cultivars of the pathogen-tested collection of the Centro Internacional de la Papa were assessed for reproductive and agronomic characteristics during three consecutive years in San Ramón, a Peruvian location in the warm lowland tropics. The clones showed significant variation for all characteristics recorded. The Shannon–Weaver diversity index (H) was highest for flowering duration (0.617) and intensity (0.600). The lowest H was calculated for bee attraction in this location. The overall H was not significantly affected by the year-to-year variation, but some of the characteristics recorded (e.g. flowers per inflorescence, anther type, style length, plus fruit and berry set) showed distinct H according to the year of assessment. Some of the cultivars with promising TPS traits, as determined by their reproductive characteristics, also had outstanding tuber set, weight and yield. Furthermore, hybrid offspring from the selected clones from the pathogen-tested elite sample, did show high tuber yield with appropriate tuber set and reproductive traits as shown by progeny testing. Hence, the approach followed for identifying parental sources as discussed in this article appears to be appropriate.     

Wastes to be the source of nutrients and energy to mitigate climate change and ensure future sustainability: options and strategies

Abstract

Waste production is associated with human inhabitation and its rate is increasing over time. Globally, the major proportion of waste is disposed of through landfilling and open dumping, which is environmentally unsafe due to emission of greenhouse gases (GHGs). Thus, in order to avoid emission of GHGs from wastes it is important to use techniques that can convert wastes to energy/nutrients on eco-friendly economical way. Furthermore, quantification of the impacts of these waste management techniques on ecosystem is also needed through the application of tools like modeling, remote sensing, geographical information system (GIS), Unmanned Aerial Vehicles (UAVs) and life cycle assessments (LCA). Thus, this review was conducted by considering focus on potential of nutrient and energy recovery techniques from various types of wastes and approaches to enhance the efficiency of the process. The outcomes depicted that the aerobic and anaerobic digestion is suitable to deal with biodegradable and organic fraction of the waste, but anaerobic digestion seem to be more sustainable waste management techniques. Additionally, the review covers the techniques to drive energy and recover nutrient from non-biodegradable proportion. Different modern analytical tools; such as remote sensing, GIS and simple/dynamic models could be useful tool to help in the decision-making processes for waste managements. These tools can help us to design integrated solid waste management processes. Finally, we suggest that LCA should be considered to determine the environmental load of material/product from its production to final disposal (from cradle to grave).     

Improving Strategic Growth Stage-based Drought Tolerance in Quinoa by Rhizobacterial Inoculation

ABSTRACT

Climate change is imposing high temperature resulting in prolonged drought episodes and shrinking of fresh water resources across the globe. In this scenario, even drought tolerant crops like quinoa are also losing significant yield. However, this study was planned to investigate the impact of drought on quinoa at critical growth stages and bacterial inoculation to improve drought tolerance. Drought was imposed by maintaining 25% pot water holding capacity (PWC) at multiple leaf, flowering, and seed filling stage (DSFS), while 80% PWC was considered as control. Three strains of plant growth promoting rhizobacteria (PGPR) named as: Bacillus licheniformis, Pseudomonas fluorescens, and Azospirillum brasilense were inoculated with quinoa seeds before sowing with respect to drought treatments. PGPR inoculation mitigated the drastic effects of drought by improving crop growth, net assimilation rate, water use efficiency, leaf chlorophyll, and phenolic contents, all of these ultimately contributed to improvement in grain yield and its contributing attributes. Moreover, PGPR markedly improves the grain quality attributes including protein, phosphorus, and potassium contents. Principal component analysis linked the different scales of study and demonstrated the potential of physio-biochemical traits to explain the quinoa yield variations under drought condition with response to PGPR inoculation. Among different PGPR, A. brasilense was found most effective both under normal and drought conditions. Overall, DSFS has more detrimental effects among critical growth stages of quinoa and A. brasilense can be used as a shotgun tactic to ameliorate drought stress in quinoa.     

Potassium fixation capacity of some highly calcareous soils as a function of clay minerals and alternately wetting-drying

ABSTRACT

The current research was done to investigate the effect of wetting-drying cycles, time, and clay mineralogy on K fixation capacity of highly calcareous soils. In order to conduct the study, eight soil samples were collected. The samples were treated with different concentrations of K including 200 (K1), 400 (K2) and 800 mg kg^?1 (K3) and 8 different incubation time including 6 h (t1), 24 h (t2), 72 h (t3), one week (t4), two weeks (t5), one month (t6), two months (t7) and three months (t8). Also, a wetting-drying treatment was done (td) in order to simulate the effect of irrigation and soil drying on K fixation. The results showed that for all K levels addition, the percentage of fixed K was increased with time. The K fixation content was increased with the increase in the added K from K1 to K3, while K fixation percentage was decreased. The results also showed that there was a significant difference between soils with wetting-drying treatment (td) and soils with three-month incubation (t8) in K fixation capacity, so that the fixation of K by the soils was increased with wetting-drying cycles.     

OPTIMUM DESIGN OF SEDIMENTATION TANKS BASED ON SETTLING CHARACTERISTICS OF KARACHI TANNERY WASTES

A study was carried out in a specially designed settling column to investigate the settling characteristics of effluents arising from Karachi tanneries. The Jar-tests were conducted to determine the optimum dosage of coagulants such as potash alum and ferric chloride to maximize the removal of suspended solids (S.S) from the wastes. For alum, the optimum dosage was found to be 150 mg L^-1, whereas with ferric chloride it was 30 mg L^-1. Experiments carried out in the settling column with the optimum coagulant dosages showed that the coagulation with ferric chloride was much better than with alum, as it removes about 84% S.S from the wastes compared to 70% removal obtained in case of alum. Design curves in terms of percent removal of S.S. vs loading rate and detention time were constructed using data obtained from settling column. These curves can be used in designing the settling tanks employed in the tannery wastes treatment plants.     

Root traits of different crops under rainfed conditions in the High Barind Tract of Bangladesh

Root traits of six different crops grown on residual soil moisture in the post–rainy season in the High Barind Tract (HBT) of Bangladesh were investigated to better understand their adaptation to this moisture‐limited environment. Deep‐rooting chickpea is the currently favored rainfed crop grown after rainy‐season rice in the HBT, but it is necessary to identify alternative crops to chickpea in order to avoid buildup of pests and diseases. Averaged over 2 y, barley (1.72 Mg ha^–1) produced significantly more grain than chickpea (1.4 Mg ha^–1) which, in turn, yielded better than linseed (1.0 Mg ha^–1), wheat (0.93 Mg ha^–1), and mustard (0.77 Mg ha^–1). Lentil did not produce any grain at all. Grain yield for all crops increased as total root length increased above a threshold value of 0.05 to 0.1 km m^–2. In general, grain yield increased as the proportion of total root produced below 60 cm depth increased, although barley also had thin roots that could more effectively extract soil moisture. Expression of root traits varied considerably between seasons, which was attributable to the different rainfall patterns and bulk‐density characteristics of the soil profile in the 2 years of the study. Although favorable root traits, particularly rooting ability below 60 cm, are a prerequisite for acceptable yield levels of crops grown on residual soil moisture in the HBT, it is recognized that farmers' choice of a post‐rice crop will depend on its economic return or food‐security value.     

Tillage effect on partial budget analysis of cropping intensification under dryland farming in Punjab,Pakistan

A 2-year research experiment was laid out in a split-plot design with moldboard ploughing (MP, control) and minimum tillage (MT) as main plots and crop sequences as sub-plots. Summer-winter cropping sequences were fallow-wheat (Triticum aestivum L.) (FW, control), mungbean (Vigna radiata L.)-wheat (MW), sorghum (Sorghum bicolor L.)-wheat (SW), green manure-wheat (GW) and mungbean-chickpea (MC) (Cicer arietinum L.). During 2010–2011, in summer, mungbean crop produced the highest above ground biomass in mungbean-chickpea sequence under MP tillage (4.24 Mg ha^–1 mungbean) and in mungbean-wheat sequence under MT tillage (4.11 Mg ha^–1 mungbean). In winter, chickpea gave the highest biomass in mungbean-chickpea sequence under both tillage systems. During 2011–2012, mungbean produced the highest above ground biomass in mungbean-wheat sequence under MT tillage (4.43 Mg ha^–1 mungbean) and in both the mungbean-chickpea and mungbean-wheat sequences under MP tillage (4.24 and 4.17 Mg ha^–1 mungbean, respectively). In winter, fallow-wheat sequence gave the highest biomass in both tillage systems. The differences in grain yields were statistically non-significant in both the years. The gross marginal benefit ranged between ?190 and 548$ ha^–1 in the first year and ?165 and 1124$ ha^–1 in the second year. The net benefit values were the highest in mung-chickpea sequence under both tillage systems (1008 and 596$ ha^–1 under MP and MT, respectively), which gave cost–benefit ratios of 5.45 and 3.68, respectively. Use of legume-based cropping sequences is a sustainable and cost-effective practice in drylands of northern Punjab, Pakistan.