Sustained Yield Management Research Articles

Sugarcane yield estimation in Thailand at multiple scales using the integration of UAV and Sentinel-2 imagery

Timely and accurate estimates of sugarcane yield provide valuable information for food management, bio-energy production, (inter)national trade, industry planning and government policy. Remote sensing and machine learning approaches can improve sugarcane yield estimation. Previous attempts have however often suffered from too few training samples due to the fact that field data collection is expensive and time-consuming. Our study demonstrates that unmanned aerial vehicle (UAV) data can be used to generate field-level yield data using only a limited number of field measurements. Plant height obtained from RGB UAV-images was used to train a model to derive intra-field yield maps based on 41 field sample plots spread over 20 sugarcane fields in the Udon Thani Province, Thailand. The yield maps were subsequently used as reference data to train another model to estimate yield from multi-spectral Sentinel-2 (S2) imagery. The integrated UAV yield and S2 data was found efficient with RMSE of 6.88 t/ha (per 10 m × 10 m pixel), for average yields of about 58 t/ha. The expansion of the sugarcane yield mapping across the entire region of 11,730 km2 was in line with the official statistical yield data and highlighted the high spatial variability of yields, both between and within fields. The presented method is a cost-effective and high-quality yield mapping approach which provides useful information for sustainable sugarcane yield management and decision-making.

Balancing phosphorus fertilization for sustainable maize yield and soil test phosphorus management: A long-term study using machine learning

ContextExcessive phosphorus (P) applications to ensure enhanced crop growth and increased profitability are commonly used, leading to declined P use efficiency and high P accumulation in most cultivated soils across north-western India. However, the effects of consistently applying excessive P fertilizers on soil test P (STP) levels, P availability, and maize production outcomes are poorly understood. ObjectivesThe study aims to find the long-term impacts of different fertilizer P application rates on maize yield, agronomic P efficiency, optimal P rates for yield maximization, and predictive models for sustainable crop production and environmental protection across soils with different STP status. MethodsThe current study collected and analysed maize plant and soil data spanning from 2011 to 2021 from an ongoing long-term field experiment conducted on three different STP status soils i.e., medium P (MPS), high P (HPS), and very high P (VHPS) soils. The experiment involves five different fertilizer P application rates No-P, 13, 26, 39, and 52 kg P ha−1. ResultsThe results indicated a significant increase in maize grain yield and P bioavailability with the application of 13 kg ha−1 of fertilizer P in VHPS (>50.0 kg P ha−1) and 26 kg ha−1 in both HPS (22.5–0.0 kg P ha−1) and MPS (12.5–22.5 kg P ha−1). Improved agronomic efficiency reducing P rate to half of the recommended 26 kg P ha−1 was estimated in VHPS. The economically optimal P rate (EOPR) model consistently sustains crop yield with lower P rates. Among the different machine learning algorithms, multiple linear regression (MLR) was found more reliable in predictive accuracy. The decrease in predicted grain yield and increase in predicted soil P accumulation at P rates of 26 kg P ha−1 and above in varying P status soils underscores the need for judicious P fertilization practices to avoid negative impacts on yield. ConclusionsThe P application required to obtain an average maize yield of 6000 kg ha−1 with relatively high P use efficiency, fertilizer P applications of 35.2 kg ha−1 in VHPS, 37.1 kg ha−1 in HPS, and 41.1 kg ha−1 in MPS based on STP status is more economical. Smart agriculture, using machine learning algorithms helps in ensuring effective P utilization over the long term while minimizing negative ecological impacts. ImplicationsThe sustainable growth of maize crops will necessitate a reduction in P application rates, and P optimization should need further attention to explore the microbial dissolution potential of residual P.

Timber, money, and shelter: The promotion of private tree planting in New Zealand during the 1920s

This article examines the promotion of private tree planting, in particular by farmers, by the New Zealand State Forest Service (SFS) as a solution to a timber shortage in the 1920s. While previous research has detailed the SFS’s efforts to ensure a stable supply of timber by placing New Zealand’s native forests under a system of sustained yield management and through the establishment of exotic plantations, it overlooks the importance the SFS placed on private tree plantations as a source of timber, expecting it to supply a third of New Zealand’s timber demand. In its propaganda, the SFS portrayed tree planting as a mean to improve the productivity of the farm and as a financial investment. To assist farmers, the SFS also sold trees and seedlings to farmers, a practice that met with major resistance from private nurserymen and political lobby organisations. By exploring the SFS’s promotion of private tree planting to farmers, this article demonstrates how the SFS built upon a tradition of experimental tree planting and promotion of exotic afforestation. Moreover, by examining the opposition to the policy of the SFS selling trees and seedlings to farmers, the article highlights the contesting notions of the state’s role in promoting private tree planting; whether it was a responsibility of the state, or an invasion on the private market. On a broader scale, this paper demonstrates how local environmental and political conditions shaped responses to a perceived global timber shortage.

Optimal dynamic spatial closures can improve fishery yield and reduce fishing-induced habitat damage

Bottom-towed fishing gears produce significant amounts of seafood globally but can result in seafloor habitat damage. Spatial closures provide an important option for mitigating benthic impacts, but their performance as a fisheries management policy depends on numerous factors, including how fish respond to habitat quality changes. Spatial fisheries management has largely focused on marine protected areas with static locations, overlooking dynamic spatial closures that change through time. To investigate the performance of dynamic closures, we develop a spatial fishery model with fishing-induced habitat damage, where habitat quality can affect both fish productivity and movement. We find that dynamic spatial closures often achieve greater harvest and habitat protection than fixed marine protected areas or conventional nonspatial maximum sustainable yield management, especially under strong habitat–stock interactions. Determining optimal dynamic spatial closures may require considerable information, but we find that simple policies of fixed-schedule rotating closures also perform well. Dynamic spatial closures have received less attention as fisheries management tools, and our results demonstrate their potential value for addressing both harvest and habitat impacts from fishing.

Exploring a relative harvest rate strategy for moderately data-limited fisheries management

Abstract Moderately data-limited fisheries can be managed with simple empirical management procedures without analytical stock assessments. Often, control rules adjust advised catches by the trend of an abundance index. We explored an alternative approach where a relative harvest rate, defined by the catch relative to a biomass index, is used and the target level derived from analysing historical catch length data. This harvest rate rule was tested generically with management strategy evaluation. A genetic algorithm was deployed as an optimisation procedure to tune the parameters of the control rule to meet maximum sustainable yield and precautionary management objectives. Results indicated that this method could outperform trend-based strategies, particularly when optimised, achieving higher long-term yields while remaining precautionary. However, optimum harvest rate levels can be narrow and challenging to find because they depend on historical exploitation and life history characteristics. Misspecification of target levels can have a detrimental impact on management. Nevertheless, harvest rates appear to be a suitable management option for moderately data-limited resources, and their application has modest data requirements. Harvest rate strategies are especially suitable for stocks for which case-specific analyses can be conducted.

Oysters beget shell and vice versa: generating management goals for live oysters and the associated reef to promote maximum sustainable yield of Crassostrea virginica

Populations of the eastern oyster (Crassostrea virginica) have experienced declines from overfishing and disease throughout much of its US range, though development of maximum sustainable yield (MSY) management criteria has been elusive. This is due in part to the discordance between oyster spawning stock and recruits, as the classic stock–recruitment model does not account for the requirement of shell substrate on which recruits settle. This issue was recently addressed with the development of a surface area–recruitment model, which is herein incorporated into a simulation analysis to estimate MSY-based reference points for C. virginica in the Delaware Bay. Simulations demonstrate that at low natural mortality, fishing mortality (F) may be sustainable at values between 10% and 15%; however, if disease or other mortality-enhancing processes occur, the margin of error in fishing is small and may quickly lead to population and reef collapse, emphasizing a precautionary F < 10%. The MSY-based reference points generated here provide rebuilding goals for the oyster fishery and reef management on fished and unfished reefs and the framework from which shell-planting can be incorporated and optimized in the future.

Decomposition of Plantain Peel Powder and Assessment of its Effects on Soil Physical and Chemical Characteristics

This study aims at assessing the effects of plantain (Musa paradisiaca) peel powder on soil physical and chemical properties in the context of sustainable yield management. The experiment took place in the laboratory of plant physiology of the University Félix Houphouët Boigny from July to November 2020. Three designs were set up. Design 1 consisted of 20 g of plantain peel powder added to a 2-cm thick layer of sea sand. Design 2 consisted of 5 g of plantain peel powder added to 250 g of sea sand. Design 3 consisted of a homogeneous mixture of 100 g of peel powder and 200 g of rhizospheric tomato or plantain soil. The designs were regularly watered with distilled water. In the first two designs, the plantain peel powder was added according to two methods. These included surface incorporation and deep incorporation. The experiment allowed us to characterize peel powder decomposition and assess its effects on soil physicochemical parameters. The physico-chemical characteristics of the soils were subjected to a one-way analysis of variance (ANOVA 1). STATICA 7.1 software was used to perform all the analyses. Analysis of the results showed that the incorporation method does not influence peel powder decomposition. This decomposition is followed by the release of colored elements. Water retention capacity as well as particle size were improved. The results showed that plantain peel powder is an important source of minerals mainly phosphorus and potassium. It emerges from this study that plantain peel could be a good organic fertilizer for profitable and environmentally friendly agriculture.

Trade‐offs between forage crop productivity and soil nutrients for different ages of alfalfa grassland

AbstractObtaining sustainable high yield and suitable soil nutrient management is crucial for cultivate alfalfa grassland. However, the information on the trade‐offs between soil nutrient and productivity of alfalfa grassland following long‐term cultivation under intensive agricultural management is scare. Six alfalfa grasslands of different ages under a highly intensive agricultural management system were chosen for this study. It was shown that long‐term planting of alfalfa reduced soil nutrients overall. In the 0–100, 100–200, and 200–300 cm layers, the highest values of soil organic carbon (SOC), soil total nitrogen (TN), and soil total phosphorus (TP) content were observed in one‐year‐old alfalfa grassland. SOC, TN, and TP contents in each 100 cm soil layers linearly declined with increasing stand age, and decreasing rates of SOC and TN (4.31 and 0.03 g kg−1 yr−1) in the 0–100 cm layer were higher than other two soil layers. The SOC storage (SOCS) and TN storage (TNS) in 0–20 cm soil were significantly higher than other soil profiles in six alfalfa grasslands of different ages. SOCS and TNS in 0–100 cm, especially in upper 40 cm soil, decreased over time until the fourth year, and gradually increased in the fifth and sixth years. While in the third and fourth years, productivity reached peak value (3.13 and 3.12 t ha−1), and then reduced. Correlation analysis showed productivity was significantly negatively correlated with SOCS and TNS in 0–100 cm soil depth. The decline in soil nutrients affected alfalfa growth and then feedback its productivity, and the optimal stand age of alfalfa grasslands should not be longer than 6 years for the limitation of soil nutrient, especially SOC storage. To acquire sustainable high productivity of artificial alfalfa grassland, our study suggested that more organic and nitrogen/phosphorus fertilizers should be applied to the upper soil layer beginning in the third year after planting.

Human Capital and Organizational Performance Based on Organizational Innovation: Empirical Study on China

It is now entering the knowledge-based economic era globally. In the new era, the real dominant resources and decisive production factors are not capital, land, or labor, but knowledge. In such an era, knowledge workers play critical roles in the business activity. Employees with knowledge would become the human capital of a company. High-tech industry has got in the giant competition era. Under the global competition and the constant innovation of knowledge-based economy, it becomes a worth discussing issue for high-tech businesses maintaining or enhancing the firm competitiveness. Aiming at high-tech industry, the supervisors and employees of high-tech businesses in Shanghai are distributed 420 copies of questionnaire. Total 322 valid copies are retrieved, with the retrieval rate 77%. The research results show significantly positive effects of 1.human capital on organizational innovation, 2.organizational innovation on organizational performance, and 3.human capital on organizational performance. According to the results, suggestions are proposed, expecting to help high-tech businesses, when encountering the challenge in the industrial environment, create more performance and benefits to achieve the sustained-yield management.

Hydrogeophysical Characterization of a Weathered-Fractured Aquifer System: A Case study of Olbanita, Lower Baringo Basin, Kenya Rift

Groundwater yields in the Kenya Rift are highly unsustainable owing to geological variability. In this study, field hydraulic characterization was performed by using geo-electric approaches. The relations between electrical–hydraulic (eh) conductivities were modeled hypothetically and calibrated empirically. Correlations were based on the stochastic models and field-scale hydraulic parameters were contingent on pore-level parameters. By considering variation in pore-size distributions over eh conduction interval, the relations were scaled-up for use at aquifer-level. Material-level electrical conductivities were determined by using Vertical Electrical Survey and hydraulic conductivities by analyzing aquifer tests of eight boreholes in the Olbanita aquifer located in Kenya rift. VES datasets were inverted by using the computer code IP2Win. The main result is that InT = 0.537(1nFa) + 3.695, the positive gradient indicating eh conduction through pore-surface networks and a proxy of weathered and clayey materials. An inverse (1/F-K) correlation is observed. Hydraulic parameters determined using such approaches may possibly contribute significantly towards sustainable yield management and planning of groundwater resources.

Correction: Herring supports Northeast Pacific predators and fisheries: Insights from ecosystem modelling and management strategy evaluation.

[This corrects the article DOI: 10.1371/journal.pone.0196307.].

Frame Analysis of ENGO Conceptualization of Sustainable Forest Management: Environmental Justice and Neoliberalism at the Core of Sustainability

Normative judgments on sustainability underpin concepts that shape the supply scenarios of timber consumption. The modern understanding of sustainable forest management is shaped by a diverse spectrum of social demands, going beyond the principle of sustainable yield management. Rival stakeholders compete to incorporate their ideas and interpretations of sustainable forest management into policy institutions. Environmental non-governmental organizations (ENGOs) have emerged as one of the dominant stakeholders in the forest-based sector. We set out to explore ENGO-specific conceptualizations of sustainable forest management and investigate differences in understanding among various ENGOs. By conducting a frame analysis of ENGO press releases, we identified two master frames: environmental justice and environmentalist frames. A difference in the emphasis placed on procedural and distributive justice as well as a different standpoint in the commons versus commodity debate emerged as the main divergences between the master frames. The results of our study demonstrate how the differences between the master frames underpin different conceptualizations of sustainable forest management. On the one hand, the ENGOs associated with the environmental justice master frame advocate for the broader implementation of community forest management based on power-sharing. On the other hand, the ENGOs associated with the environmentalist master frame promote a wide range of approaches associated with ecosystem management and social forestry paradigms. Moreover, the ENGOs associated with the environmentalist master frame challenge the concept of sustainable forest management as defined by the Helsinki and Montreal process by advocating for ecosystem management. The ENGOs associated with the environmental justice master frame reject the mainstream concept of sustainable forest management in any guise. Future research on ethical issues underlying forestry concepts may provide more conceptual and operational clarity for both forest managers and policy-makers.

Herring supports Northeast Pacific predators and fisheries: Insights from ecosystem modelling and management strategy evaluation

This paper analyzes the trophic role of Pacific herring, the potential consequences of its depletion, and the impacts of alternative herring fishing strategies on a Northeast Pacific food web in relation to precautionary, ecosystem-based management. We used an Ecopath with Ecosim ecosystem model parameterized for northern British Columbia (Canada), employing Ecosim to simulate ecosystem effects of herring stock collapse. The ecological impacts of various herring fishing strategies were investigated with a Management Strategy Evaluation algorithm within Ecosim, accounting for variability in climatic drivers and stock assessment errors. Ecosim results suggest that herring stock collapse would have cascading impacts on much of the pelagic food web. Management Strategy Evaluation results indicate that herring and their predators suffer moderate impacts from the existing British Columbia harvest control rule, although more precautionary management strategies could substantially reduce these impacts. The non-capture spawn-on-kelp fishery, traditionally practiced by many British Columbia and Alaska indigenous peoples, apparently has extremely limited ecological impacts. Our simulations also suggest that adopting a maximum sustainable yield management strategy in Northeast Pacific herring fisheries could generate strong, cascading food web effects. Furthermore, climate shifts, especially when combined with herring stock assessment errors, could strongly reduce the biomasses and resilience of herring and its predators. By clarifying the trophic role of Pacific herring, this study aims to facilitate precautionary fisheries management via evaluation of alternative fishing strategies, and thereby to inform policy tradeoffs among multiple ecological and socioeconomic factors.

A Study on the Correlations among Product Design, Statistics Education, and Purchase Intention – A Case of Toy Industry

Being affected by the rapid change in internal and external environments in past years, the fiercer competition has resulted in the declination of toy industry. For the sustained-yield management, toy manufacturers have been searching for strategies. In the consumer-oriented era, an enterprise has to precede statistics education of toy designers so that the market survey could accurately analyze consumer needs to establish differential products for creating product value and meeting consumer needs. The supervisors, employees, and customers of Traxxas are the major research subjects for the questionnaire survey in this study. Total 300 copies of questionnaire are distributed and 236 valid copies are retrieved, with the retrieval rate 79%. The research results reveal significantly positive correlations between 1.product design and purchase intention, 2.statistics education and product design, and 3.statistics education and purchase intention. According to the results, suggestions are proposed, expecting to assist domestic toy manufacturers in the future development of product design for the sustained-yield management.

Ecosystem-based management and the wealth of ecosystems

We merge inclusive wealth theory with ecosystem-based management (EBM) to address two challenges in the science of sustainable management of ecosystems. First, we generalize natural capital theory to approximate realized shadow prices for multiple interacting natural capital stocks (species) making up an ecosystem. These prices enable ecosystem components to be better included in wealth-based sustainability measures. We show that ecosystems are best envisioned as portfolios of assets, where the portfolio's performance depends on the performance of the underlying assets influenced by their interactions. Second, changes in ecosystem wealth provide an attractive headline index for EBM, regardless of whether ecosystem wealth is ultimately included in a broader wealth index. We apply our approach to the Baltic Sea ecosystem, focusing on the interacting community of three commercially important fish species: cod, herring, and sprat. Our results incorporate supporting services embodied in the shadow price of a species through its trophic interactions. Prey fish have greater shadow prices than expected based on market value, and predatory fish have lower shadow prices than expected based on market value. These results are because correctly measured shadow prices reflect interdependence and limits to substitution. We project that ecosystem wealth in the Baltic Sea fishery ecosystem generally increases conditional on the EBM-inspired multispecies maximum sustainable yield management beginning in 2017, whereas continuing the current single-species management generally results in declining wealth.

Faustmann formula before Faustmann in German territorial states

A common perception in forest and natural resource economics is that the celebrated ‘Faustmann formula’ was discovered in 1849 and that the ‘Faustmann rule’ or Faustmann–Pressler solution to the optimal forest rotation age was derived from it a decade later by Max Robert Pressler. This paper shows that the modern perspective to the valuation of forests was presented in German territorial states much earlier than has previously been thought. In 1805 a competent forest mathematician Johann Hossfeld showed explicitly how forest value can be derived under both intermittent and sustained yield management, thus discovering the Faustmann formula. The study also shows that the close intellectual and professional connections among the first German ‘forest economists’ seem to have played a key role in the diffusion of modern forest economic principles from Hossfeld and his contemporaries to Faustmann and Pressler, and perhaps even more generally to modern capital theory.

Own-price elasticity of open access supply as a long-run measure of fish stock abundance

Extensive criticisms of the management of marine fisheries periodically arise for a variety of reasons. While the complexity of the US fisheries management process is partially to blame, these reasons manifest themselves in statements that include a perceived decline in living marine resource abundance levels, a proposed change in the regulatory infrastructure, or improvements in stock abundance that some feel should allow for new entrants. Following these criticisms are calls to end the federal management process or at the very least the replacement of the fishery management agency leadership. These demands driven by rent seeking behavior use short-term declines in abundance as justification when the long-run abundance measures would have indicated improvements in stock abundance and achievement of management objectives. Empirical, long-run, stock abundance indices are estimated using synthetic demand methodology, based on bioeconomic fishery theory, applied in a general and partial equilibrium theory framework to determine if maximum sustainable yield (MSY) management targets have been achieved and maintained for four fisheries considered to be successfully managed and one characterized as a socio-economic disaster. The abundance of a fish stock is more influence by extra-market and extra-fishery forces than by fisheries managers who base allocation decisions solely on single species stock assessments.

Regional trade-offs from multi-species maximum sustainable yield (MMSY) management options

The maximum sustainable yield (MSY) is, theoretically, the largest yield that can be taken from a single species' stock over an indefinite period. Formulation of strategic MSY management goals is, however, complicated by the need to move beyond biological single-species considerations. Interactions among species necessitate multispecies (MMSY) definitions, incorporating ecological, economic and social considerations. We developed an ecological-economic model of the Baltic Sea, simulating stock dynamics of interacting populations of cod Gadus morhua, herring Clupea harengus and sprat Sprattus sprattus. We investigated a set of different strategic management options. These likely, yet non-formalized experiments evaluate and illuminate alternative regional trade-offs. We computed multi-species maximum economic yield (MMEY) under certain eco-logical constraints, with profits as a performance indicator. An unconstrained profit-maximizing management strategy would lead to a highly profitable cod fishery in a cod-dominated ecosystem. Concurrent sprat stock size (and profits) would be low, falling below ecological precautionary reference points. Consideration of ecological constraints on minimum stock sizes leaves a range of strategies, including the change from a cod-dominated to a more clupeid-dominated system. The regional distribution of profits depends on the management. Therefore, adjustment payments or other forms of compensation might be needed to achieve a concordant agreement on strategic multi-species management goals.

Locking Horns with Hawai‘i’s Non-native Ungulate Issues

Author(s): Hess, Steven C. | Abstract: Conservation and management interests for sustained-yield hunting of non-native ungulates in Hawai‘i have conflicted with the conservation of native biota for several decades. Hawaiian ecosystems evolved in the absence of large mammals and all currently hunted animals in Hawai‘i are non-native species. The best-studied aspects of Hawai‘i’s ungulates have dealt primarily with direct negative effects on native biota in natural areas, but there has been little research in population dynamics for sustained-yield management. Ungulates have been removed from approximately 750 km2 throughout the Hawaiian Islands to protect these natural areas, thereby reducing the amount of land area available for hunting activities and the maintenance of game populations. At the same time, unauthorized introductions of additional wild ungulate species between Hawaiian Islands have recently increased in frequency. The majority of hunting activities are of feral domestic livestock species for subsistence purposes, which typically do not generate sufficient revenue to offset costs of game management. Moreover, bag limits and seasons are generally not determined from biological criteria because harvest reporting is voluntary and game populations are rarely monitored. Consequently, ungulate populations cannot be managed for any particular level of abundance or other objectives. Research and monitoring which emphasize population dynamics and productivity would enable more precisely regulated sustained-yield game management programs and may reduce potential conflicts with the conservation of native biota.

Implications of uncertainty in the spawner–recruitment relationship for fisheries management: An illustration using bigeye tuna (Thunnus obesus) in the eastern Pacific Ocean

The impacts of the steepness parameter of the Beverton–Holt spawner–recruitment curve on fisheries stock assessment and management performance were evaluated, using data for bigeye tuna (Thunnus obesus) in the eastern Pacific Ocean. The analysis was conducted using the Stock Synthesis model. The estimates of maximum sustainable yield (MSY) and related management reference points are sensitive to the value of steepness (ranging from 0.4 to 1.0) of the Beverton–Holt spawner–recruitment relationship assumed in the assessment model. Steepness also impacts the evaluation of stock status. A lesser value assumed for steepness leads to a more pessimistic evaluation of the stock status regarding whether the stock is overfished or overfishing is occurring. However, a lesser value does not reduce the estimates of MSY due to the interaction between steepness and the estimates of other model parameters. When managing the stock under effort limitation using MSY-based fishing mortality, a lower assumption of steepness yields less expected losses in catch than does a higher assumption. This is due to the flatness of the yield curve when the steepness is high. A lower assumption of steepness also maintains a higher level of spawning biomass and recruitment.