scholarly journals WATER MANAGEMENT STRATEGIES UNDER DEFICIT IRRIGATION

2008 ◽  
Vol 39 (4) ◽  
pp. 27 ◽  
Author(s):  
Antonino Capra ◽  
Simona Consoli ◽  
Baldassare Scicolone
Keyword(s):  
Water Management ◽  
Deficit Irrigation ◽  
Management Strategies ◽  
Yield Reduction ◽  
Research Approach ◽  
Total Production ◽  
Economic Aspects ◽  
Optimization Strategy ◽  
Full Irrigation ◽  
Positive Effects

Deficit irrigation (DI) is an optimization strategy whereby net returns are maximized by reducing the amount of irrigation water; crops are deliberated allowed to sustain some degree of water deficit and yield reduction. Although the DI strategy dates back to the 1970s, this technique is not usually adopted as a practical alternative to full irrigation by either academics or practitioners. Furthermore, there is a certain amount of confusion regarding its concept. In fact, a review of recent literature dealing with DI has shown that only a few papers use the concept of DI in its complete sense (e.g. both the agronomic and economic aspects). A number of papers only deal with the physiological and agronomical aspects of DI or concern techniques such as Regulated Deficit Irrigation (RDI) and Partial Root Drying (PRD). The paper includes two main parts: i) a review of the principal water management strategies under deficit conditions (e.g. conventional DI, RDI and PRD); and ii) a description of a recent experimental research conducted by the authors in Sicily (Italy) that integrates agronomic, engineering and economic aspects of DI at farm level. Most of the literature reviewed here showed, in general, quite positive effects from DI application, mostly evidenced when the economics of DI is included in the research approach. With regard to the agronomic effects, total fresh mass and total production is generally reduced under DI, whereas the effects on dry matter and product quality are positive, mainly in crops for which excessive soil water availability can cause significant reductions in fruit size, colour or composition (grapes, tomatoes, mangos, etc.). The experimental trial on a lettuce crop in Sicily, during 2005 and 2006, shows that the highest mean marketable yield of lettuce (55.3 t ha-1 in 2005 and 51.9 t ha-1 in 2006) was recorded in plots which received 100% of ET0-PM (reference evapotranspiration by the Penman- Monteith method) applied water. In the land-limiting case, the estimated optimal economic levels were quite similar to the optimal agronomic levels. In the waterlimiting case DI ranges, at least as profitable as full irrigation, were of 17-49% ET0-PM and of 71-90% ET0-PM in 2005 and 2006 respectively.

scholarly journals Effect of Grafting on Growth, Yield, and Verticillium Wilt of Eggplant

HortScience ◽  
2003 ◽  
Vol 38 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Fotios Bletsos ◽  
Costas Thanassoulopoulos ◽  
Demetrios Roupakias
Keyword(s):  
Verticillium Wilt ◽  
Wild Species ◽  
Disease Incidence ◽  
Yield Reduction ◽  
Infested Soil ◽  
Total Production ◽  
Solanum Torvum ◽  
Average Value ◽  
Positive Effects ◽  
Early Production

Eggplant (Solanum melongena L.) seedlings (`Tsakoniki') were grafted by hand on the Verticillium dahliae Kleb. resistant wild species Solanum torvum Sw. (GST) and Solanum sisymbriifolium Lam. (GSS). Grafted and nongrafted eggplants were transplanted to a fumigated soil with methyl bromide and to infested soil with microsclerotia of V. dahliae. Grafted plants were more vigorous, as measured by plant height, main stem diameter, and root system weight, than the nongrafted `Tsakoniki'. This resulted in an increased early production (GST, 45.5%; GSS, 18.4%) and late production (GST, 69.3%; GSS, 59.2%) as compared to the noninfected controls. The mean yield reduction (over years) in early production caused by the disease, as compared to the controls grown in fumigated soil, was 29.4%, 36.6%, and 77.9% for eggplant grafted on S. torvum, S. sisymbriifolium, and nongrafted plants, respectively. This yield reduction in total production was 6.9%, 20.5%, and 56.8%, respectively. The disease incidence in ungrafted plants was 96% and 100% during early and late harvest periods. In contrast, the disease incidence in grafted plants was significantly lower, averaging 28.1% (GST) and 52.6% (GSS) in early production, and 37.6% and 79.3%, respectively, in late production. Solanum torvum was found more resistant than S. sisymbriifolium, because grafted infected plants developed mild symptoms, as indicated by significantly lower leaf symptom index (average value 1.2 and 2.22) and disease index (average value 1.55 and 3.38), respectively. In conclusion, grafting of eggplant on either wild species had positive effects on growth, production, and verticillium wilt control.

scholarly journals Deficit irrigation as a sustainable option for improving water productivity in Sub-Saharan Africa: the case of Ethiopia. A Critical Review 

2021 ◽  
Author(s):  
Desale Asmamaw ◽  
Mekete Desse ◽  
Seifu Tilahun ◽  
Enyew Adgo ◽  
Jan Nyssen ◽  
...  
Keyword(s):  
Water Scarcity ◽  
Deficit Irrigation ◽  
Crop Production ◽  
Water Productivity ◽  
Irrigation Scheduling ◽  
Sub Saharan Africa ◽  
Yield Reduction ◽  
Limiting Factor ◽  
Full Irrigation ◽  
Sub Saharan

<p>Water scarcity is a major limiting factor for crop production by irrigation in sub-Saharan countries. Improved irrigation scheduling that can ensure the optimal use of the allocated water and enhance water productivity (WP) is required to address future water scarcity in the region. Maximizing WP by exposing the crop to a certain level of water stress using deficit irrigation (DI) is considered a promising strategy. To adopt DI strategies, a shred of comprehensive evidence concerning DI for different crops is required. This review aims to provide adequate information about the effect of DI on WP. We reviewed 90 research papers from Ethiopia and summarize the effect of DI on WP and yield. It is shown that DI considerably increased WP compared to full irrigation. Despite higher WP, reduced biomass yield was obtained in some of the studied DI practices compared to full irrigation. It was also found that yield reduction may be low compared to the benefits gained by diverting the saved water to irrigate extra arable land. From this review, we understood that growers must recognize specific soil management and crops before applying DI strategies. Maize revealed the highest (2.65 kg m<sup>-3</sup>) and lowest (0.50 kg m<sup>-3</sup>) WP when irrigated at only the initial stage compared with being fully irrigated in all growth stages, respectively. Also, onion showed a decreasing WP with increased irrigation water from 60% crop water requirement (ETc) (1.84 kg m<sup>-3</sup>) to 100% ETc (1.34 kg m<sup>-3</sup>). Increasing water deficit from 100 to 30% ETc led to an increase of wheat WP by 72.2%. For tomato, the highest WP (7.02 kg m<sup>-3</sup>) was found at 70% ETc followed by 50% ETc (6.98 kg m<sup>-3</sup>) and 85% ETc (6.92 kg m<sup>-3</sup>), while the water application of 100% ETc (or full irrigation) showed the least WP (6.79 kg m<sup>-3</sup>). Teff showed the lowest WP (1.72 kg m<sup>-3</sup>) under optimal irrigation, while it was highest (2.96 kg m<sup>-3</sup>) under 75% ETc throughout the growing season. The regression analysis (R<sup>2</sup>) for WP increment and yield reduction versus saved water showed higher values, indicating that DI could be an option for WP increment and increasing overall yield by expanding irrigated area and applying the saved water in water-scarce regions. In conclusion, in areas where drought stress is the limiting factor for crop production, the application of DI is feasible.</p><p> </p><p> </p><p> </p><p>Keywords: Overall yield increase, water productivity, water saved, yield reduction</p>

Concepts and Practices for Improving Nitrogen Management for Vegetables

1992 ◽  
Vol 2 (1) ◽  
pp. 121-125 ◽  
Author(s):  
George J. Hochmuth
Keyword(s):  
Water Management ◽  
Management Practices ◽  
Management Strategies ◽  
N Fertilization ◽  
Nitrogen Management ◽  
Land Grant ◽  
Land Grant Universities ◽  
Production Practices ◽  
Negative Impacts ◽  
N Management

Efficient N management practices usually involve many potential strategies, but always involve choosing the correct amount of N and the coupling of N management to efficient water management. Nitrogen management strategies are integral parts of improved production practices recommended by land-grant universities such as the Institute of Food and Agricultural Sciences, Univ. of Florida. This paper, which draws heavily on research and experience in Florida, outlines the concepts and technologies for managing vegetable N fertilization to minimize negative impacts on the environment.

A Performance-Based Regulatory Program for Phosphorus Control to Prevent the Accelerated Eutrophication of Lake Okeechobee, Florida

1993 ◽  
Vol 28 (3-5) ◽  
pp. 13-26 ◽  
Author(s):  
Alan L. Goldstein ◽  
Gary J. Ritter
Keyword(s):  
Water Management ◽  
Field Studies ◽  
South Florida ◽  
Lake Okeechobee ◽  
Cost Share ◽  
Scientific Application ◽  
Ongoing Research ◽  
Positive Effects ◽  
Regulatory Program ◽  
A Performance

Following 15 years of data collection, field studies, and modeling efforts, the State of Florida in 1987 legislatively mandated the South Florida Water Management District, a regional water management agency, to create and implement a plan to reduce average annual inputs of total phosphorus to Lake Okeechobee by 40 percent. One element of the resulting plan was the creation and implementation of a performance-based regulatory program that set phosphorus discharge limitations for all parcels of land equal to or greater than 1/2 acre in size in almost all of the 1,735,000 acres of the lake's 31 tributary drainage basins. Owners of non-complying parcels are required to take measures to bring the parcels into compliance. This regulatory program, coupled with concurrent cost-share incentive programs and ongoing research efforts, has resulted in a decrease in phosphorus concentrations from individual properties and at some tributary discharge locations to the lake. This effort demonstrates that where there is sufficient historical information, scientific application of state-of-the-art modeling techniques, a political will, and appropriate powers vested in the institutions to take and enforce actions, such programs can be implemented and have positive effects on reducing non-point source pollutants.

scholarly journals Cyanobacterial Abundance and Microcystin Profiles in Two Southern British Lakes: The Importance of Abiotic and Biotic Interactions

Toxins ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 503 ◽  
Author(s):  
David M. Hartnell ◽  
Ian J. Chapman ◽  
Nick G. H. Taylor ◽  
Genoveva F. Esteban ◽  
Andrew D. Turner ◽  
...  
Keyword(s):  
Water Management ◽  
Linear Regression Analysis ◽  
Management Strategies ◽  
Biotic Interactions ◽  
Cost Effective ◽  
Multiple Linear Regression Analysis ◽  
Tandem Mass ◽  
Recreational Waters ◽  
Cyanobacteria Blooms ◽  
Freshwater Bodies

Freshwater cyanobacteria blooms represent a risk to ecological and human health through induction of anoxia and release of potent toxins; both conditions require water management to mitigate risks. Many cyanobacteria taxa may produce microcystins, a group of toxic cyclic heptapeptides. Understanding the relationships between the abiotic drivers of microcystins and their occurrence would assist in the implementation of targeted, cost-effective solutions to maintain safe drinking and recreational waters. Cyanobacteria and microcystins were measured by flow cytometry and liquid chromatography coupled to tandem mass spectrometry in two interconnected reservoirs varying in age and management regimes, in southern Britain over a 12-month period. Microcystins were detected in both reservoirs, with significantly higher concentrations in the southern lake (maximum concentration >7 µg L−1). Elevated microcystin concentrations were not positively correlated with numbers of cyanobacterial cells, but multiple linear regression analysis suggested temperature and dissolved oxygen explained a significant amount of the variability in microcystin across both reservoirs. The presence of a managed fishery in one lake was associated with decreased microcystin levels, suggestive of top down control on cyanobacterial populations. This study supports the need to develop inclusive, multifactor holistic water management strategies to control cyanobacterial risks in freshwater bodies.

scholarly journals Photosynthetic efficiency and production of cowpea cultivars under deficit irrigation

2018 ◽  
Vol 13 (5) ◽  
pp. 1 ◽  
Author(s):  
Alberto Soares de Melo ◽  
Allisson Rafael Ferreira da Silva ◽  
Alexson Filgueiras Dutra ◽  
Wellison Filgueiras Dutra ◽  
Marcos Eric Barbosa Brito ◽  
...  
Keyword(s):  
Water Deficit ◽  
Deficit Irrigation ◽  
Photosynthetic Efficiency ◽  
Arid Regions ◽  
Carbon Fixation ◽  
Management Strategies ◽  
Carbon Assimilation ◽  
Green Beans ◽  
Gas Exchanges ◽  
Cowpea Cultivars

Cowpea is a crop with great economic, social and food importance in semi-arid regions, but its production is drastically reduced by the water deficit in these regions, requiring better management strategies that allow the crop’s production. This study therefore aimed to evaluate the photosynthetic efficiency and production of cowpea cultivars under deficit irrigation replacement levels. The experiment tested three cowpea genotypes (G1 = ‘BRS Aracé’, G2 = ‘BR 17 Gurguéia’ and G3 = ‘BRS Marataoã’) and four irrigation depths (40, 60, 80 and 100% of ETc), resulting in a 3 x 4 factorial scheme, arranged in randomized complete blocks design with four replicates. During the experiment, the gas exchanges, chlorophyll a fluorescence and production of the cowpea genotypes under deficit irrigation were evaluated. Carbon fixation in the photosynthetic metabolism of cowpea plants was reduced by accentuated water deficit, regardless of the genotype. The low stress severity was indicated by the lack of effects on chlorophyll fluorescence, indicating that the reduction in the rate of carbon assimilation was due to the stomatal effects. The irrigation with 80% of ETc can be used in the cultivation of the respective cultivars, but with small losses in the production. Among the genotypes, ‘BRS Marataoã’ stands out with respect to yield, with higher values for weight of pods and green beans.

scholarly journals Water Management Strategies Against Toxic Microcystis Blooms In The Dutch Delta

2006 ◽  
Vol 16 (1) ◽  
pp. 313-327 ◽  
Author(s):  
Jolanda M. H. Verspagen ◽  
Jutta Passarge ◽  
Klaus D. Jöhnk ◽  
Petra M. Visser ◽  
Louis Peperzak ◽  
...  
Keyword(s):  
Water Management ◽  
Management Strategies ◽  
Microcystis Blooms ◽  
Dutch Delta

scholarly journals A co-cultivation process of Nannochloropsis oculata and Tisochrysis lutea induces morpho-physiological and biochemical variations potentially useful for biotechnological purposes

2021 ◽  
Author(s):  
Michele Maglie ◽  
Costanza Baldisserotto ◽  
Alessandra Guerrini ◽  
Alessandra Sabia ◽  
Lorenzo Ferroni ◽  
...  
Keyword(s):  
Lipid Production ◽  
Maximum Yield ◽  
Pharmaceutical Products ◽  
Nannochloropsis Oculata ◽  
Production Costs ◽  
Yield Reduction ◽  
Total Biomass ◽  
Tisochrysis Lutea ◽  
Positive Effects ◽  
Cell Extracts

AbstractThe biotechnological potential of microalgae has gained considerable importance in many applied fields: biomass production for food and feed, cosmeceutical and pharmaceutical products, energy and phytoremediation. The driving force that inspires the progress in microalgae production is the need for new cultivation systems to obtain simultaneously the maximum yield, reduction of water and nutrients use, and production of economically interesting molecules, such as pigments, fatty acids and polysaccharides. We aim to test, for the first time, the co-cultivation in saline medium of Tisochrysis lutea (Haptophyta) and Nannochloropsis oculata (Ochrophyta) to obtain valuable compounds, i.e. pigments and lipids characteristic of each species, using a single culture process. Mono-cultures of each strain were used as controls. The two strains showed an increase in the concentration of chlorophylls and carotenoids in co-culture. At the end of the experiment, the fatty acid profile was analysed by gas chromatography–mass spectrometry. The lipids in the co-cultivated cell extracts were mainly attributable to N. oculata, which represented 97% of the total cells (ca. 83% of the total biomass) at the end of the experiment. Nevertheless, the ω-3 characteristic of T. lutea (DHA and SDA, absent in N. oculata) was also detectable. Although the co-cultivation of these two phylogenetically different species of microalgae did not show positive effects on the growth and on the total lipid production, however, this process resulted in a reduction of the production costs and a lower consumption of water and nutrients.

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