scholarly journals Quantifying Water Quality Improvements through Use of Precision Herbicide Application Technologies in a Dry-Tropical, Furrow-Irrigated Cropping System

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2326
Author(s):  
Aaron M. Davis ◽  
Catherine Neelamraju
Keyword(s):  
Water Quality ◽  
Weed Management ◽  
Cropping System ◽  
Farming System ◽  
Freshwater Ecosystems ◽  
Practice Change ◽  
Quality Improvements ◽  
Herbicide Application ◽  
Relative Risks ◽  
System Use

This study compared water quality effects of using precision herbicide application technologies and traditional spraying approaches across several regulated ‘priority’ and alternative pre- and post-emergent herbicides in a northern Australian cane farming system. Use of herbicide banding spray technologies resulted in pre-emergent herbicide load reductions, extending substantially beyond simple proportionate decreases in the amount of herbicide ingredient applied to paddocks. Aquatic risk assessment from resultant chemical mixtures leaving paddocks, and upscaled to local catchment concentrations, highlighted that precision application technologies could markedly reduce the ecological risk of pre-emergent herbicides. These risk reductions were, however, often complicated by the additional toxicity of post-emergent herbicides in mixtures, some associated with the adoption of band-spraying weed treatments. While the currently regulated priority herbicide, diuron, posed the greatest risk to the environment, alternative herbicides could still pose significant environmental risks, although these relative risks were lower at more ecologically relevant concentrations, typically found in the local freshwater ecosystems. Results underline the need for a carefully considered approach to integrating alternative herbicides and precision application technologies into improved weed management by irrigating cane farmers. Recent government changes to the appraisal of water quality improvement progress, from load-based to ecosystem-based targets, involving a much broader suite of herbicides, also appear likely to complicate assessment of the environmental impacts of practice change adoption for the industry.

scholarly journals Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality

2019 ◽  
Vol 116 (41) ◽  
pp. 20562-20567 ◽  
Author(s):  
Sarah M. Stackpoole ◽  
Edward G. Stets ◽  
Lori A. Sprague
Keyword(s):  
Water Quality ◽  
Freshwater Ecosystems ◽  
Quality Improvements ◽  
Current Conservation ◽  
Continental Scale ◽  
Crop Uptake ◽  
P Fertilizer ◽  
River Export ◽  
Quality Response ◽  
External P Loading

Phosphorus (P) fertilizer has contributed to the eutrophication of freshwater ecosystems. Watershed-based conservation programs aiming to reduce external P loading to surface waters have not resulted in significant water-quality improvements. One factor that can help explain the lack of water-quality response is remobilization of accumulated legacy (historical) P within the terrestrial-aquatic continuum, which can obscure the beneficial impacts of current conservation efforts. We examined how contemporary river P trends (between 1992 and 2012) responded to estimated changes in contemporary agricultural P balances [(fertilizer + manure inputs)—crop uptake and harvest removal] for 143 watersheds in the conterminous United States, while also developing a proxy estimate of legacy P contribution, which refers to anthropogenic P inputs before 1992. We concluded that legacy sources contributed to river export in 49 watersheds because mean contemporary river P export exceeded mean contemporary agricultural P balances. For the other 94 watersheds, agricultural P balances exceeded river P export, and our proxy estimate of legacy P was inconclusive. If legacy contributions occurred in these locations, they were likely small and dwarfed by contemporary P sources. Our continental-scale P mass balance results indicated that improved incentives and strategies are needed to promote the adoption of nutrient-conserving practices and reduce widespread contemporary P surpluses. However, a P surplus reduction is only 1 component of an effective nutrient plan as we found agricultural balances decreased in 91 watersheds with no consistent water-quality improvements, and balances increased in 52 watersheds with no consistent water-quality degradation.

scholarly journals The impact of different weed management strategies on weed flora of wheat-based cropping systems

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247137
Author(s):  
Muhammad Shahzad ◽  
Khawar Jabran ◽  
Mubshar Hussain ◽  
Muhammad Aown Sammar Raza ◽  
Leonard Wijaya ◽  
...  
Keyword(s):  
Weed Management ◽  
Cropping Systems ◽  
Management Strategies ◽  
Cropping System ◽  
Herbicide Application ◽  
Water Extracts ◽  
The World ◽  
Weed Flora ◽  
Weed Infestation ◽  
The Impact

The world population will rise in future, which would demand more wheat production to fulfil dietary needs of wheat-dependent population of the world. Food security in wheat-dependent regions will greatly rely on wheat productivity. Weed infestation is a major constraint reducing wheat productivity globally. Nonetheless, cropping systems and weed management strategies strongly influence weed infestation in modern agriculture. Herbicides are the key weed management tool in conventional agriculture. However, frequent use of herbicides have resulted in the evolution of herbicide-resistance weeds, which made weed management a challenging task. Sustainable and eco-friendly weed management strategies shift weed-crop competition in the favour of crop plants. Limited studies have evaluated the interactive effect of cropping systems and weed management strategies on weed flora of wheat-based cropping systems (WBCSs). This two-year study evaluated the impact of different weed management strategies (WMSs) on weed flora of WBCSs, i.e., fallow-wheat (FW), rice-wheat (RW), cotton-wheat (CW), mungbean-wheat (MW) and sorghum-wheat (SW). The WMSs included in the study were, false seedbed, allelopathic water extracts and herbicide application, while weed-free and weedy-check were maintained as control treatments. Data relating to diversity and density of individual and total broadleaved and narrow-leaved weeds were recorded. The WBCSs, WMSs and their interaction significantly altered diversity and density of individual, total, broadleaved and narrow-leaved weeds. Weed-free and weedy-check treatments recorded the lowest and the highest values of diversity and density of individual, total, broadleaved and narrow-leaved weeds. Herbicide application effectively reduced density and diversity of weeds. Allelopathic water extracts and false seedbed proved less effective than herbicides. On the other hand, SW cropping system not only reduced weed density but also limited the weed flora. It is concluded that false seedbed and SW cropping system can be efficiently used to manage weeds in WBCSs. However, long-term studies are needed to infer the impact of SW cropping system and false seedbed on soil properties, soil microbes and productivity of wheat crop.

scholarly journals A Review of Long-Term Organic Comparison Trials in the U.S.

2015 ◽  
Vol 4 (3) ◽  
pp. 5 ◽  
Author(s):  
Kathleen Delate ◽  
Cynthia Cambardella ◽  
Craig Chase ◽  
Robert Turnbull
Keyword(s):  
Weed Management ◽  
Carbon Capture ◽  
Cropping System ◽  
Farming System ◽  
Climatic Conditions ◽  
Environmental Data ◽  
Supporting Evidence ◽  
Organic Systems ◽  
The U.S

<p>Long-term organic farming system trials were established across the U.S. to capture baseline agronomic, economic and environmental data related to organic conversion under varying climatic conditions. These sites have proven useful in providing supporting evidence for successful transition from conventional to organic practices. All experiments chosen for this review were transdisciplinary in nature; analyzed comprehensive system components (productivity, soil health, pest status, and economics); and contained all crops within each rotation and cropping system each year to ensure the most robust analysis. In addition to yield comparisons, necessary for determining the viability of organic operations, ecosystem services, such as soil carbon capture, nutrient cycling, pest suppression, and water quality enhancement, have been documented for organic systems in these trials. Outcomes from these long-term trials have been critical in elucidating factors underlying less than optimal yields in organic systems, which typically involved inadequate weed management and insufficient soil fertility at certain sites. Finally, these experiments serve as valuable demonstrations of the economic viability of organic systems for farmers and policymakers interested in viewing farm-scale organic operations and crop performance.</p>

scholarly journals Crop diversification for weed management in organic arable cropping systems

2015 ◽  
Vol 2 ◽  
pp. 333 ◽  
Author(s):  
Livija Zarina ◽  
Barbel Gerowitt ◽  
Bo Melander ◽  
Jukka Salonen ◽  
Roman Krawczuk ◽  
...  
Keyword(s):  
Weed Management ◽  
Cover Crop ◽  
Cropping Systems ◽  
Cropping System ◽  
Red Clover ◽  
Farming System ◽  
Crop Diversification ◽  
Crop Species ◽  
Perennial Weeds ◽  
Arable Farming

<p>Within the ERA-net CORE Organic Plus transnational programmes supported project PRODIVA producing of the information required for a better utilization of crop diversification for weed management in North European organic arable cropping systems was started. To fulfill the goal of this project- not to eradicate weed problems, which is unlikely to happen in any arable farming system, but to maintain a diversified and manageable weed flora that can support beneficial organisms- there were data from ongoing long-termed cropping system experiments from Latvia analyzed.</p><p>It is hypothesised that: a) perennial weeds can be suppressed in the post-harvest period by improved cover crop establishment and pertinent selection of cover crop species; b) on-farm practices of crop diversification are related to weed pressure and species composition.</p><p class="R-MainText">On the bases on data from organic farm and ongoing long-termed cropping system experiment on weed dynamics in six-field crop rotations with cover crop was concluded that red clover as cover crop after the harvest period is effective to manage perennial weeds. In crop rotation with higher proportions of cereals weed infection growth in six-field rotation with 50% share of cereals up to 3.4, but with 33.3 %  share-up to 2.1 times.</p>

scholarly journals The role of bud bank in glyphosate tolerance of two herbaceous species

2019 ◽  
Vol 54 (4) ◽  
pp. 553-565
Author(s):  
Elisa S. Panigo ◽  
Ignacio M. Dellaferrera ◽  
Carlos A. Alesso ◽  
Abelardo C. Vegetti ◽  
Mariel G. Perreta
Keyword(s):  
Weed Management ◽  
Cropping System ◽  
Bud Bank ◽  
Herbicide Application ◽  
Glyphosate Tolerance ◽  
Perennial Weeds ◽  
Term Management ◽  
Rhizome System

Background and aims: Commelina erecta and Eutsachys retusa are two perennial weeds, which show high resprouting after glyphosate application. This behavior represents a serious problem for weed management. The purpose of this study was to characterize the bud bank of both species and to assess their response to glyphosate application. M&M: We analyzed 120 reproductive shoots of C. erecta, and 80 reproductive shoots of E. retusa, at 30- and 60-days post- herbicide application. The doses applied to C. erecta were 0 (control), 1.200 and 2.400 g a.i. ha -1 , and to E. retusa were 0 (control), 480 and 1200 g a.i. ha -1 . Results: We found that both species presented active buds in approximately 50% of their nodes, even after herbicide application. Bud bank dynamics changed in both weeds after herbicide application, and therefore their growth pattern. The activation of originally inhibited buds allowed weeds to regrow and survive after glyphosate application altering their architecture. Conclusions: The bud bank plays an important role in glyphosate tolerance in both weeds. The resprouting capacity in both species was similar for any dose of glyphosate applied. Therefore, an alternative control strategy based on the increase of the dose of herbicide would not be a successful alternative for the management of these weeds. The interruption of the storage of reserves in the rhizome system and the reduction of the number of buds would be key to effective long-term management of these and other perennial weeds in no tillage cropping system.

scholarly journals The implications of lag times between nitrate leaching losses and riverine loads for water quality policy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. W. McDowell ◽  
Z. P. Simpson ◽  
A. G. Ausseil ◽  
Z. Etheridge ◽  
R. Law
Keyword(s):  
Water Quality ◽  
Mean Transit Time ◽  
Lag Time ◽  
Practice Change ◽  
N Leaching ◽  
N Losses ◽  
Leaching Losses ◽  
Nitrate N ◽  
The Mean ◽  
Lag Times

AbstractUnderstanding the lag time between land management and impacts on riverine nitrate–nitrogen (N) loads is critical to understand when action to mitigate nitrate–N leaching losses from the soil profile may start improving water quality. These lags occur due to leaching of nitrate–N through the subsurface (soil and groundwater). Actions to mitigate nitrate–N losses have been mandated in New Zealand policy to start showing improvements in water quality within five years. We estimated annual rates of nitrate–N leaching and annual nitrate–N loads for 77 river catchments from 1990 to 2018. Lag times between these losses and riverine loads were determined for 34 catchments but could not be determined in other catchments because they exhibited little change in nitrate–N leaching losses or loads. Lag times varied from 1 to 12 years according to factors like catchment size (Strahler stream order and altitude) and slope. For eight catchments where additional isotope and modelling data were available, the mean transit time for surface water at baseflow to pass through the catchment was on average 2.1 years less than, and never greater than, the mean lag time for nitrate–N, inferring our lag time estimates were robust. The median lag time for nitrate–N across the 34 catchments was 4.5 years, meaning that nearly half of these catchments wouldn’t exhibit decreases in nitrate–N because of practice change within the five years outlined in policy.

scholarly journals Weeds Hosting the Soybean Cyst Nematode (Heterodera glycines Ichinohe): Management Implications in Agroecological Systems

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 146
Author(s):  
Leonardo F. Rocha ◽  
Karla L. Gage ◽  
Mirian F. Pimentel ◽  
Jason P. Bond ◽  
Ahmad M. Fakhoury
Keyword(s):  
Weed Management ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Integrated Management ◽  
Cropping System ◽  
Cyst Nematode ◽  
Weed Species ◽  
Initial Inoculum ◽  
Herbicide Resistant ◽  
Sites Of Action

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is a major soybean-yield-limiting soil-borne pathogen, especially in the Midwestern US. Weed management is recommended for SCN integrated management, since some weed species have been reported to be hosts for SCN. The increase in the occurrence of resistance to herbicides complicates weed management and may further direct ecological–evolutionary (eco–evo) feedbacks in plant–pathogen complexes, including interactions between host plants and SCN. In this review, we summarize weed species reported to be hosts of SCN in the US and outline potential weed–SCN management interactions. Plants from 23 families have been reported to host SCN, with Fabaceae including most host species. Out of 116 weeds hosts, 14 species have known herbicide-resistant biotypes to 8 herbicide sites of action. Factors influencing the ability of weeds to host SCN are environmental and edaphic conditions, SCN initial inoculum, weed population levels, and variations in susceptibility of weed biotypes to SCN within a population. The association of SCN on weeds with relatively little fitness cost incurred by the latter may decrease the competitive ability of the crop and increase weed reproduction when SCN is present, feeding back into the probability of selecting for herbicide-resistant weed biotypes. Therefore, proper management of weed hosts of SCN should be a focus of integrated pest management (IPM) strategies to prevent further eco–evo feedbacks in the cropping system.

scholarly journals Declining bacteria, lead, and sulphate, and rising pH and oxygen in the lower Mississippi River

AMBIO ◽  
2021 ◽  
Author(s):  
R. Eugene Turner
Keyword(s):  
Water Quality ◽  
Mississippi River ◽  
Pollution Abatement ◽  
National Policy ◽  
Quality Improvements ◽  
Sulfur Dioxide Emissions ◽  
Dramatic Decline ◽  
Before And After ◽  
Lower Mississippi River ◽  
The 1960S

AbstractVarious air and water pollution issues in the US were confronted in the last 60 years using national policy legislation, notably the Clean Water Act and the Clean Air Act. I examine changes in the concentrations of bacteria, oxygen, lead, and sulphate at the terminus of the Mississippi River before and after these pollution abatement efforts. Microbial concentrations increased or were stable from 1909 to 1980 but decreased about 3 orders of magnitude after the 1970s, while the average oxygen content increased. A large decline in lead concentration occurred after the 1960s, along with a less dramatic decline in sulphate concentrations. The pH of the river dropped to a low of 5.8 in 1965 as sulfur dioxide emissions peaked and averaged 8.2 in 2019 after emissions declined. Decades of efforts at a national scale created water quality improvements and are an example for addressing new and existing water quality challenges.

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