•The regulated deficit irrigation (RDI0.8) did not affect the marketable fruit yield (MFY) as compared with the full irrigation (FI).•The MFY was improved by 4% with DI0.6 at vegetative stage while a ...decline of 7% was monitored with DI0.6 at fruiting stage.•The DI0.6 applied at either of two stages vegetative & flowering, flowering & fruiting and vegetative & fruiting resulted in 14–18% decline in MFY.•The crop was able to tolerate interruptions of irrigation for 15 days at three growth stages and the decline in yield was only 3–7%.•The Deficit irrigation (DI) improved the quality of tomato in terms of total soluble solid, ascorbic acid, acidity and colour index.
A field experiment was conducted for two years (2013–15) to evaluate the response of tomato (Lycopersicon esculentum Mill.) to deficit irrigation (DI) with drippers. The options tried were either the regulated DI on the basis of climatological approach i.e. irrigation water equalling 0.6, 0.8 and 1.0 times the evapotranspiration (ET) or DI (0.6xET) at phenological stages (vegetative, flowering, fruiting, vegetative-cum-flowering, vegetative-cum-fruiting and flowering-cum-fruiting stages) and disrupting irrigation (15 days) at either of vegetative, flowering and fruiting stage. Compared with the full irrigation (FI; 78.0Mgha−1) the regulated deficit irrigation though did not affect the marketable fruit yield (MFY) at RDI0.8, there was loss of about one-fourth MFY with RDI0.6. Nevertheless the water productivity (19.2kgm−3) was the maximum under RDI0.8. When the deficit irrigation was applied at different growth stages, MFY was rather improved by 4% with DI0.6(VS) while DI0.6(FL) showed little effect and a decline of 7% was monitored with DI0.6(FT). The DI applied at either of two stages (DI0.6(VS+FL); DI0.6(FL+FT); DI0.6(VS+FT)) resulted in 14–18% decline in MFY. The crop was able to tolerate interruptions of irrigation for 15 days at the above phenological stages i.e. simulating canal closures and the decline in yield was only 3–7%, the highest being at fruiting stages (IIFT). The major advantage of DI was improvement in quality in terms of total soluble solid, ascorbic acid, acidity and colour index (lycopene) though the fruit size was affected. It was concluded that benefits of deficit irrigation in terms of improved quality and water productivity while sustaining fruit yield could be achieved with regulated DI at 0.8xET and DI at 0.6xET during vegetative stage followed by flowering.
The common cutworm, Spodoptera litura, has become a major pest of soybean (Glycine max) throughout its Indian range. With a changing climate, there is the potential for this insect to become an ...increasingly severe pest in certain regions due to increased habitat suitability. To examine this possibility, we developed temperature-based phenology model for S. litura, by constructing thermal reaction norms for cohorts of single life stages, at both constant and fluctuating temperatures within the ecologically relevant range (15-38°C) for its development. Life table parameters were estimated stochastically using cohort updating and rate summation approach. The model was implemented in the geographic information system to examine the potential future pest status of S. litura using temperature change projections from SRES A1B climate change scenario for the year 2050. The changes were visualized by means of three spatial indices demonstrating the risks for establishment, number of generations per year and pest abundance according to the temperature conditions. The results revealed that the development rate as a function of temperature increased linearly for all the immature stages of S. litura until approximately 34-36°C, after which it became non-linear. The extreme temperature of 38°C was found lethal to larval and pupal stages of S. litura wherein no development to the next stage occurred. Females could lay no eggs at the extreme low (15°C) and high (> 35°C) test temperatures, demonstrating the importance of optimum temperature in determining the suitability of climate for the mating and reproduction in S. litura. The risk mapping predicts that due to temperature increase under future climate change, much of the soybean areas in Indian states like Madhya Pradesh, Maharashtra and Rajasthan, will become suitable for S. litura establishment and increased pest activity, indicating the expansion of the suitable and favourable areas over time. This has serious implication in terms of soybean production since these areas produce approximately 95% of the total soybeans in India. As the present model results are based on temperature only, and the effects of other abiotic and biotic factors determining the pest population dynamics were excluded, it presents only the potential population growth parameters for S. litura. However, if combined with the field observations, the model results could certainly contribute to gaining insight into the field dynamics of S. litura.
The volume of wastewater generated by domestic, industrial and commercial sources has increased with population, urbanization, improved living conditions, and economic development. The productive use ...of wastewater has also increased, as millions of small-scale farmers in urban and peri-urban areas of developing countries depend on wastewater or wastewater polluted water sources to irrigate high-value edible crops for urban markets, often as they have no alternative sources of irrigation water. Undesirable constituents in wastewater can harm human health and the environment. Hence, wastewater irrigation is an issue of concern to public agencies responsible for maintaining public health and environmental quality. For diverse reasons, many developing countries are still unable to implement comprehensive wastewater treatment programs. Therefore in the near term, risk management and interim solutions are needed to prevent adverse impacts from wastewater irrigation. A combination of source control, and farm-level and post-harvest measures can be used to protect farm workers and consumers. The WHO guidelines revised in 2006 for wastewater use suggest measures beyond the traditional recommendations of producing only industrial or non-edible crops, as in many situations it is impossible to enforce a change in the current cash crop pattern, or provide alternative vegetable supply to urban markets.
There are several opportunities for improving wastewater management via improved policies, institutional dialogues and financial mechanisms, which would reduce the risks in agriculture. Effluent standards combined with incentives or enforcement can motivate improvements in water management by household and industrial sectors discharging wastewater from point sources. Segregation of chemical pollutants from urban wastewater facilitates treatment and reduces risk. Strengthening institutional capacity and establishing links between water delivery and sanitation sectors through inter-institutional coordination leads to more efficient management of wastewater and risk reduction.
Deficit irrigation (DI) and plant growth regulators (PGRs) have strategic role for sustaining crop productivity and mitigating water stress in drought prone areas. However, their impacts are yet to ...be quantified for eggplant (Solanum melongena L.), a popular drought tolerant vegetable crop grown in water scarce Deccan Plateau of India. We conducted field experiments during 2016–17 and 2017–18 in a drought prone region of Deccan Plateau, India to evaluate the interactive effect of PGRs viz., 1.38 mg L−1 salicylic acid (SA), 1.5% potassium nitrate (PN), 500 ppm thio-urea (TU) and 100 ml L−1 bio-stimulant (BS) and varied levels of DI generated using line source sprinkler system. The marketable fruit yields were reduced to 86, 74, 50, 30, 12 and 8% with increased level of DI i.e. when the applied irrigation water (IW) equalled 0.00, 0.15, 0.30, 0.45, 0.60 and 0.75 times the cumulative open pan evaporation (CPE) against the recommended irrigation practice (IW:CPE 0.90). Application of PGRs improved fruit yields by 7.3–22.7% and their role to alleviate water stress was indicated by lower canopy temperatures, maintaining higher leaf relative water content, modulation of stomatal opening and higher consumptive use of water. Particularly SA and TU were superior under low to medium water stress (IW:CPE 0.45–0.75) whereas PN was effective in severe water stress (IW:CPE 0.0–0.44) while the effect of BS was almost similar with PGRs like TU under medium stress conditions. The maximum water productivity (WP) varied between 5.50 and 6.77 kg m−3 for different PGRs and it was 5.16 kg m−3 without PGRs indicating water savings to the order of 28.8–57.4% with the former. The fruit quality attributes such as mean diameter, sphericity, fruit weight and firmness traits declined with water stress while these were considerably rectified with PGRs. Higher accumulation of dry matter, sugar, protein, total phenolics, flavonoids and improved rehydration quality as well as potentially affecting enzymatic activity were monitored with PGRs. It is concluded that exogenous application of PGRs like SA and PN along with medium levels of DI can help in rational utilization of water resources and could effectively improve yield and post-harvest quality of eggplant fruits especially under water scarce environment of Deccan Plateau.
Display omitted
•Eggplant responses to PGRs and DI practices in water scarce environment were investigated.•PGRs improved fruit yield (7.3–22.7%) and water productivity (5.50–6.77 kg m−3).•Salicylic acid (SA) and potassium nitrate (PN) were found effective in alleviating water stress.•PGRs with medium DI upregulated marketable and physicochemical fruit quality characteristics.
Halotolerant bacteria associated with
Psoralea corylifolia
L., a luxuriantly growing annual weed in salinity-affected semi-arid regions of western Maharashtra, India were evaluated for their plant ...growth-promoting activity in wheat. A total of 79 bacteria associated with different parts viz., root, shoot and nodule endophytes, rhizosphere, rhizoplane, and leaf epiphytes, were isolated and grouped based on their habitat. Twelve bacteria isolated for their potential in plant growth promotion were further selected for in vitro studies. Molecular identification showed the presence of the genera
Bacillus
,
Pantoea
,
Marinobacterium
,
Acinetobacter
,
Enterobacter
,
Pseudomonas
,
Rhizobium
, and
Sinorhizobium
(LC027447-53; LC027455; LC027457, LC027459, and LC128410). The phylogenetic studies along with carbon source utilization profiles using the Biolog® indicated the presence of novel species and the
in planta
studies revealed promising results under salinity stress. Whereas the nodule endophytes had minute plant growth-promoting (PGP) activity, the cell free culture filtrates of these strains enhanced seed germination of wheat (
Triticum aestivum
L). The maximum vigor index was monitored in isolate Y7 (
Enterobacter
sp strain NIASMVII). Indole acetic acid (IAA) production by the isolates ranged between 0.22 and 25.58 μg mL
−1
. This signifies the need of exploration of their individual metabolites for developing next-generation bio-inoculants through co-inoculation with other compatible microbes. This study has potential in utilization of the weed-associated microbiome in terms of alleviation of salinity stress in crop plants.
The fisheries and livestock sectors capture the highest share of protein-rich animal food and demonstrate accelerated growth as an agriculture subsidiary. Environmental pollution, climate change, as ...well as pathogenic invasions exert increasing stress impacts that lead the productivity momentum at a crossroads. Oxidative stress is the most common form of stress phenomenon responsible for the retardation of productivity in fisheries and livestock. Essential micronutrients play a determinant role in combating oxidative stress. Selenium, one of the essential micronutrients, appears as a potent antioxidant with reduced toxicity in its nanoscale form. In the present review, different methods of synthesis and characterization of nanoscale selenium have been discussed. The functional characterization of nano-selenium in terms of its effect on growth patterns, feed digestibility, and reproductive system has been discussed to elucidate the mechanism of action. Moreover, its anti-carcinogenic and antioxidant potentiality, antimicrobial and immunomodulatory efficacy, and fatty acid reduction in liver have been deciphered as the new phenomena of nano-selenium application. Biologically synthesized nano-selenium raises hope for pharmacologically enriched, naturally stable nanoscale selenium with high ecological viability. Hence, nano-selenium can be administered with commercial feeds for improvising stress resilience and productivity of fish and livestock.
Increasing the productivity of water and making safe use of poor quality waters in agriculture will play a vital role in easing competition for scarce water resources, prevention of environmental ...degradation and provision of food security. Driven by the pressure to produce more, even the saline and alkali waters are being increasingly diverted to irrigated agriculture. Development of salinity, sodicity and toxicity problems in soils not only reduces crop productivity and quality but also limit the choice of crops. There are two major approaches to improving and sustaining productivity in a saline environment: modifying the environment to suit the plant and modifying the plant to suit the environment, but the former has been tried more extensively. The available options are mediated through the management of crops/sequences, irrigation water, chemical/amendments and other cultural practices but all must be integrated as per the site specific needs and achieving higher yields on sustainable basis. Some important interventions include appropriate crop/variety selection, blending saline/alkali and fresh water to keep the resultant salinity below threshold, or their cyclic application by scheduling irrigation with salty water at less salt sensitive stages. At the farm/irrigation system level, policy measures like re-allocation of water to higher value crops and those with limited irrigation requirement, spatial re-allocation and transfer of water, adopting policies that favor development of water markets and adequate utilization of groundwater can help in improving water productivity in saline environments. The other viable options include salinity tolerant agro-forestry systems and bio-saline agriculture. Besides technological advances, peoples’ participation and favorable water use and allocation policies need to be put in place for sustainable use of saline/alkali waters.
•Wheat responses to supplemental irrigation and plant bio-regulators(PBR’s) studied.•Application of PBR’s improved 5.9–20.6% grain yield and 4.8-15.3% total biomass.•Integrating PBR’s with irrigation ...enhanced water productivity (1.20–1.35kgm−3).•Thiourea, salicylic acid helped to mitigate water stress in water scarcity regions.
Understanding the effects of water stress on yield formation is essential for planning irrigation and other mitigation strategies in arid and semiarid regions. Therefore, a field experiment was conducted for 3 years to evaluate the impact of irrigation regimes and plant bio-regulators (PBR’s) on grain yield and water productivity of spring wheat (Triticum aeastivum L). PBR’s applied through exogenous sprays included: 10mM thiourea (TU), 10μM salicylic acid (SA), 15gL−1 potassium nitrate (KNO3), 25ppm gibberellic acid (GA3), 8ppm ortho-silicic acid (OSA) at crown root initiation (CRI), flag leaf and seed milking stages and control (no PBR). Seven irrigation levels were generated through a line source sprinkler system (LSS) viz., application of irrigation water (IW) equalling 1.0, 0.85, 0.70, 0.55, 0.40, 0.25 and 0.10 times the CPE (cumulative open pan evaporation). The maximum yield obtained with PBR’s varied between 4.11–4.46Mgha−1 at IW:CPE 0.85 against 4.09Mgha−1 without PBR. While the yield decline equalled 0.35–0.42Mgha−1 for every 0.1 IW:CPE for PBR’s against 0.43Mgha−1 without PBR. The overall improvement in grain yield and total biomass with PBR’s ranged between 5.9–20.6% and 4.8–15.3%, respectively. Specifically TU and SA showed a major role under medium (IW:CPE 0.40–0.69) and severe (0.10–0.39) stress conditions in terms of maintenance of leaf water content, modulating the stomatal opening and better water usage and thereby improved yield by 0.41–0.88Mgha−1. The maximum water productivity ranged between 1.20–1.35kgm−3 with different PBR’s while it was 1.18kgm−3 without PBR and the latter could be achieved with 19–56% lesser irrigation water with PBR’s. Overall conclusions are that the effects of deficit irrigation could be substantially enhanced in terms of grain yield and water productivity when used conjunctively with PBR’s like TU and SA. Thus for integrating PBR’s with supplemental irrigation, large scale testing is required for defining their economic spray schedules under water scarcity conditions.
Long-term irrigation with sewage water adds large amounts of carbon, major and micro- nutrients to the soil. We compared the spatial distribution of N, P, K and other micronutrients and toxic ...elements in the top 0.6 m of an alluvial soil along with their associated effects on the composition of crops and ground waters after about three decades of irrigation with domestic sewage effluent as a function of distance from the disposal point. Use of sewage for irrigation in various proportions improved the organic matter to 1.24–1.78% and fertility status of soils especially down to a distance of 1 km along the disposal channel. Build up in total N was up to 2908 kg ha
−1, available P (58 kg ha
−1), total P (2115 kg ha
−1), available K (305 kg ha
−1) and total K (4712 kg ha
−1) in surface 0.15 m soil. Vertical distribution of these parameters also varied, with most accumulations occurring in surface 0.3 m. Traces of NO
3–N (up to 2.8 mg l
−1), Pb (up to 0.35 mg l
−1) and Mn (up to 0.23 mg l
−1) could also be observed in well waters near the disposal point thus indicating initiation of ground water contamination. However, the contents of heavy metals in crops sampled from the area were below the permissible critical levels. Though the study confirms that the domestic sewage can effectively increase water resource for irrigation but there is a need for continuous monitoring of the concentrations of potentially toxic elements in soil, plants and ground water.
PDF
