Sustainable Yield Research Articles

ORGANIC FERTILIZER: NEED OF INDIA

Organic fertilizers are naturally available mineral sources that contain moderate amount of plant essential nutrients. They are capable of mitigating problems associated with synthetic fertilizers. They reduce the necessity of repeated application of synthetic fertilizers to maintain soil fertility. They gradually release nutrients into the soil solution and maintain nutrient balance for healthy growth of crop plants. They also act as an effective energy source of soil microbes which in turn improve soil structure and crop growth. Organic fertilizers are generally thought to be slow releasing fertilizers and they contain many trace elements. They are safer alternatives to chemical fertilizers. However, the improper use of organic fertilizers leads to overfertilization or nutrient deficiency in the soil. Hence, controlled release of organic fertilizers is an effective and advanced way to overcome these impacts and maintain sustainable agriculture yield.[a]

Fishery and stock dynamics of ribbonfish Trichiurus lepturus (Linnaeus, 1758) in the Indian Exclusive Economic Zone

The fishery and stock dynamics of Trichiurus lepturus (Linnaeus, 1758) were studied in the Indian Exclusive Economic Zone (EEZ) for the period 2014-2019. The average annual landing was 2,09,285 t and varied from 1,77,259 to 2,39,355 t. Trawl nets were the majorgear, contributing more than 85% with an average annual catch rate of 4.56 kg h-1. The annual catch rate decreased over the years from 5.40 to 3.85 kg h-1. Landings (23,155-40,354 t) and catch rates (4.24-8.67 kg h-1) were highest during the post-monsoon months (September-December). Around 63% of the landings (1,32,072 t) were from the north-west coast, with Gujarat alone contributing three-fourth (98,296 t) of it, followed by the south-west coast (17%, 36,017 t), the south-east coast (12%, 25,322 t) and the north-east coast (8%, 15,875 t). The von Bertalanffy’s growth equation was Lt = 143.8 [1-e–0.48 (t + 0.03285)]. Natural mortality, Exploitation ratio and Maximum Sustainable Yield (MSY) were 0.76; 0.65 and 1,59,504 t respectively. Recruitment was substantial throughout the year with a single modal peak during June-October. With lower lengths at first capture and recruitment and with exploitation above the maximum permissible level and landings higher than MSY; the species appears to be overexploited along the Indian coasts. The present study is the first holistic report on the population parameters and stock status of T. lepturus from the Indian EEZ. Keywords: Cutlass fishes, Management, Recruitment, Stock dynamics

ANALYSIS Catch Per Unit Effort (CPUE) AND Maimum Sustainable Yield (MSY) MALE MACKEREL (Rastrelliger kanagurta) FLYING IN THE SAMUDERA FISHING LAND (PPS) KENDARI

The Banda Sea is an Indonesian water body that holds potential for small pelagic fisheries resources. Situated between Sulawesi Island and Maluku, it is part of the Fisheries Management Area Of The Republic Of Indonesia (WPP-NRI 714), Male mackerel (Rastrelliger kanagurta) is one of the fish species with high economic value, greatly favored by the community for consumption. This has led to an increase in its capture rates. Therefore, the research aims to determine the CPUE and MSY of Indian mackerel in the Kendari Ocean Fisheries Port. Data collection was conducted at the Kendari Ocean Fisheries Port from logbooks, and the research lasted from November to December 2023. The results showed that the standard fishing gear used to catch these fish is purse seine. The status of the utilization of the fishery resources is said to be experiencing underfishing. Based on the research results, the maximum sustainable yield (MSY) is 96,386 kg/year, with an optimal fishing effort of 2,300 trips/year (Fox model).

Analyzing the Trade-Offs between Soil Health Enhancement, Carbon Sequestration, and Productivity in Central India’s Black Soil through Conservation Agriculture

The impact of conservation tillage (CST) practices on soil properties, carbon sequestration and yield sustainability over short, medium, and long durations remain insufficiently understood, especially in semiarid Central India. Therefore, our objective was to investigate the effects and optimal duration of CST adoption for enhancing soil properties, carbon sequestration, and sustainable yields. We conducted a study in farmers’ fields in the Akola district of Central India, where CST had been practised for 4 to 15 years, within a soybean + pigeon pea–chickpea cropping sequence. Our findings revealed significant (p < 0.05) improvements in soil physical properties with short-term CST practices (4 to 6 years), alongside increasing availability of nitrogen and phosphorus, with longer durations of CST implementation (10 to 15 years). The lowest soil organic carbon (SOC) was observed in conventional tillage (CT_y), while all CST practices increased SOC content over CT_y, ranging from 22.2 to 38.4%. Further, experimental soil dominated passive C pools (Cfrac3 + Cfrac4). Consequently, long-term CST practices facilitated positive C sequestration rates, contrasting with negative or minimal sequestration observed in CT_y and short-term CST treatments. However, compared to CST, CT_y demonstrated higher soybean equivalent yields and comparable chickpea equivalent yields mainly due to delayed germinations induced by lower soil temperatures in CST plots. We conclude that integrating site-specific characteristics, management practices, and regional climate conditions into conservation agriculture frameworks maximizes efficacy and ensures sustainable productivity. These findings help optimize agricultural practices considering potential yield losses or minimal changes despite implementing CST.

Response of Tomato Varieties against Root-Knot Nematodes Fauna from Poonch Highlands, Azad Jammu and Kashmir

Root-knot nematode (RKN) is an important group of plant pathogens with wide distribution among tropical and temperate areas with extensive host range among cultivated and wild plants. Tropical RKN species M. incognita, M. javanica and M. arenaria are distributed in temperate areas of Azad Jammu and Kashmir. This study focused on virulence of RKN fauna on tomato crop from highlands Poonch division and their virulence study on 7 leading tomato cultivars with objective of resistance identification among accepted cultivars grown in the region. Tomato was found cultivated on 68% of surveyed sites, while 78.5% fields were found infested with RKN. Galling index was higher than 5.9 on 34 locations, among them 21 farms were located above 4500-6800ft from sea level which was not usual. RKN found infesting as single species, ore in combinations of three. Highest virulent strain combinations of RKN was used to check the performance of leading tomato cultivars in greenhouse. Screening results showed Sahel, Adventa and Roma as resistance genotypes against RKN while Hero and yellow pear were found moderately resistant, while Black cherry moderately susceptible and Money maker highly susceptible even in temperate conditions. Sahel and Hero were found with least infested with 30% and 38% disease incidence. The study will help in reducing RKN threat on low temperature highland areas by cultivating of resistant genotypes reducing RKN reproduction by providing as opportunity for sustainable yield

Evaluating the effect of organic NPK granules on yield, nutrient uptake, post-harvest soil fertility and soil microbial population in rice (Oryza sativa L.)

Rice is the most important and staple food crop for more than two third of population of India. India is the second largest rice producing country in the world after China. Although, rice planted area in India is 40 per cent higher than in China, Indian rice production is 30 percent below Chinese production because of lower yields. Among several constraints of production, nutrient management plays a key role in realizing sustainable yield from any given cultivation practices. Integrated nutrient management system plays a vital role in balancing the soil fertility and plant nutrient supply to an optimum level through the judicious and efficient use of chemical fertilizers, green manure, FYM and biofertilizers leading to an eco-friendly approach and economically viable solution for this problem. Continuous integrated use of organic manures with chemical fertilizers would be quite promising in assessing the sustainability of a cropping system vis-à-vis monitoring the soil properties. To investigate further, a field experiment was conducted at the Experimental Farm, Department of Agronomy, Annamalai University, Annamalai Nagar, Cuddalore district of Tamil Nadu from June to September 2023 with a key objective of evaluating the effect of combined application of graded levels of conventional fertilizers along with organic NPK granules in lowland rice. The experiment was laid out in randomized block design with seven treatments comprised of different levels of conventional fertilizers along with organic NPK granules. Among the nutrient management evaluated, all the yield attributes of lowland rice viz., grain yield, straw yield, uptake of nutrients and post-harvest soil available nutrients were significantly influenced by the application of 70% NPK through synthetic fertilizers and 30% NPK through organic granules. Combining conventional fertilizers along with organic NPK granules improved nitrogen use efficiency via metabolite production, enzyme activity stimulation, and microbial rhizosphere interactions significantly enhancing the yield attributes and yield.

Identifying limit reference points for robust harvest control rules in fisheries management

Risk and uncertainty are intrinsic characteristics of natural resources that must be taken into account in their management. Harvest control rules (HCR) used to be the central management tool to control stock fisheries in an uncertain context. A typical HCR determines fishing mortality as a linear relationship of the biomass binding only when the biomass is above a critical risk value. Choosing the linear relationship and the risk value is a complex task when there is uncertainty because it requires a high level of data and an in-deep knowledge of the stock. This paper fully characterizes robust HCRs that explicitly include scientific uncertainty using the robust control theory approach. Our theoretical findings show that under uncertainty: i) Constant HCRs are not robust; ii) Robust HCRs show a steeper linear relationship between fishing mortality and biomass and a higher value of biomass to be consider at risk than non-robust HCRs. From the implementation viewpoint, we assume a three-sigma rule and show that robustness is achieved by selecting a fishing mortality such that its deviation from the fishing mortality target is twice the deviation of the biomass from the biomass target, and the critical value of the biomass (the point below which fishing should cease, or become as close to zero as possible) is half of the biomass associated with the maximum sustainable yield when this is the target.

Response to Pumping of Wells in Carbonate and Karst Aquifers and Effect on the Assessment of Sustainable Well Yield: Some Examples from Southern Italy

Carbonate and karst aquifers are of great importance for human water supplies, for supporting aquatic habitats and providing ecosystem services. Optimizing the groundwater withdrawals is therefore essential for obtaining the maximum flow rate for human purposes while minimizing the negative effects on the environment. In particular, when the abstraction of groundwater occurs through wells, the problem of defining the sustainable yield arises. This study analyzes pumping tests conducted in carbonate and karst aquifers in southern Italy to derive indications for defining the sustainable yield of yields. The four examined cases concern the Mesozoic–Cenozoic platform and transition pelagic carbonate rocks characterized by different degree of fracturing and karstification and hosting a carbonate aquifer with variable average groundwater yields. The analysis compared drawdown–time trends and their derivatives for 35 pumping tests with theoretical curves to identify the flow dimension. Parameters useful for examining the well yields were then determined. The results show that the response to the pumping of the investigated aquifers is very variable, both among the different sites and within the same site. Well yields are very different due to aquifer heterogeneity, local hydrostratigraphy and structural setting, and position of the pumping center within the groundwater flow system. To determine the operational pumping rate for a well in this environment, this study emphasizes the importance of analyzing drawdown trends over time to correctly predict the well’s long-term response to pumping. Specifically, when pumping induces a steady-state drawdown response, the focus for defining the sustainable abstraction shifts to the basin or aquifer scale. Conversely, when a transient drawdown response to pumping results, the well’s capacity to capture groundwater becomes the primary factor for well yield and its sustainability.

A Holistic Approach to the Selection of Soybean (Glycine max) Cultivars for Shade Environments Based on Morphological, Yield and Genetic Traits

ABSTRACTThe reduction of photosynthetically active radiation impacts the growth and productivity of soybean in agroforestry and intercropping systems. Thus, this report explored the responses of 16 soybean cultivars submitted to shade levels in field conditions. Multi‐faceted and relative importance analyses revealed that the steam diameter and plant height are fundamental morphological markers for selecting shade‐resilient cultivars, both were high and positively correlated to yield components. Moreover, the responses to shade varied among soybean cultivars, with certain genotypes demonstrating distinct tolerance levels, which allowed also the estimative of genetic variance that revealed strong participation of genetic components in responses to shade. Multivariate and clustering analysis using steam diameter and plant height in combination with two yield components resulted in the identification of four soybean cultivars more tolerant to shade environments and two sensible. Therefore, this report provides insights into soybean cultivation under varying light conditions, provides a robust foundation for the integration of morphological and yield markers in breeding programmes focused on shade tolerance and guides future endeavours in crop improvement for optimal and sustainable yield and resilience in the climate change context.

EVALUATION OF MORPHOBIOLOGICAL AND PRODUCTIVE INDICATORS OF POTATO CULTIVARS (Solanum tuberosum l.) IN THE AREA OF MYZEQE, LUSHNJE

The potato is spread all over the world, being planted in plain, hilly, sub-mountain, and mountain areas. In Albania, 10,000 to 14,000 ha of early, medium, and late potatoes are planted. In recent years, the yield of potatoes in large-scale production has increased for two reasons: First, it is planted in more productive soils and under irrigated conditions, so there are improvements in cultivation. Secondly, new cultivars with higher biological productive capacity have been introduced into cultivation. The study of morphobiological and productive indicators of potato cultivars is ongoing to achieve high and sustainable yields. This also includes the study carried out in Zhama, Lushnje, in which eleven cultivars were included, specifically: La Perla, Valencia, Aleksjo, Gaya 1, Amora, Gaya 2, Juveli, Fidel, Solo, Zisi and Melene 2. The experiment was set up on light soils according to a randomized block design with eleven variants and four replications. Planting was done with the workforce in two days, on February 8 and 9, 2023. During the vegetation, ten plants for each variant and repetition were determined on which biometric and production measurements were made, such as Plant height, number of shoots per plant, production per plant, number of grains per plant, production in percentage by weight; up to 30 g, 31 - 80 g, 81 - 120 g and over 120 g. The data was processed to determine the best cultivar.

Hunting bag statistics of wild mammals in Portugal (1989–2022): on the need to improve data report and compilation

Wildlife monitoring is key for the effective management of natural resources. Hunting-based data (e.g., hunting bag statistics) is an important source of information to overcome the financial constraints imposed to long-term monitoring. Here, taking advantage of three decades (1989–2022) of hunting bag statistics of wild mammals in Portugal, we present the trends and discuss the issues regarding nine game species (five wild ungulates, two carnivores and two lagomorphs). Our results show that hunting bag statistics mirror the general population trends of wild mammal populations at a national scale. The data reflects the increase in number and distribution of roe deer, red deer and wild boar, and the recent expansion experienced by the Egyptian mongoose. The decline in the numbers of European wild rabbit and Iberian hare harvested are also noticeable. Hunting-based data have been used in several research contexts; however, this information is usually affected by geographical, temporal and recording bias. Portugal is no exception. Engaging the interested stakeholders is pivotal to ensure data quality. By reporting reliable and systematically collected hunting data, game managers and wildlife researchers will be able to better understand the main drivers of population dynamics, adjust hunting bags towards sustainable yield and assess the ecological and socio-economic relevance of the hunting sector.

Strategic management of nano-fertilizers for sustainable rice yield, grain quality, and soil health

Conventional fertilizers, although widely available, are relatively low in nutrient use efficiency and cause serious environmental concerns like eutrophication, greenhouse gas (GHG) emissions, nitrate poisoning, and soil pollution. With this in mind, a randomized block design (RBD) experiment was conducted in an experimental field taking 10 treatments and 3 replications to investigate the effects of integrated approaches of nano-formulated DAP fertilizer applications on rice growth, yield, and nutrient use efficiency over conventional approaches. The result revealed that plant height, panicle length, number of tillers hill−1, total number of grain panicle−1, and root length were maximum in T10 treatment (50% of the soil test recommended doses (STD) for N and P + seedling root dipping (SRD) with nano DAP at 5 mL L−1 + twice foliar sprays (FS) with nano DAP at 4 mL L−1 at 25 and 45 DAT (date after transplanting). The highest mean grain yields (4.12 and 4.05 Mg ha−1) and nutrient uptake were recorded in the T2 treatment (100% STD), but this was at par with T10 treatment. The highest benefit–cost ratio (2.26) was recorded in T10, which was 3.5% higher than T2. N and P agronomic use efficiency (AUE) ranged from 7.5% to 31.5% and 15% to 63%, and recovery efficiency (RE) ranged from 30% to 94.2% and 11.2% to 90.4%. The highest nutrient use efficiency was recorded with T10, followed by T9, and lowest in T4. Post-harvest soil pH and available N and P were significantly highest in T10. Soil MBC, MBN, MBP, urease, and phosphatase activity were found significantly higher in T2, followed by T10. The integrated application of 50% STD for N and P + SRD with nano DAP at 5 mL L-1 + twice FS with nano DAP at 4 mL L−1 at 25 and 45 DAT application can be a suitable substitute for conventional DAP and urea for rice in climate-smart agriculture as it possibly reduces environmental pollution while undisturbing crop yield over the 100% STD.

Effect of Pit and Soil Types on Growth and Development, Nutrient Content and Fruit Quality of Pomegranate in the Central Deccan Plateau Region, India

To enhance pomegranate production on marginal gravelly lands, standardized planting techniques were evaluated in an 8-year-old orchard. Trenching, wider pit excavation, pit digging, and auger digs with dimensions of 1 and 2 m were employed. Utilizing native soil from barren land, with or without spent wash, and mixing it with black soil up to 1 m deep, growth parameters, leaf nutrients, fruit production, and fruit quality were assessed. The trench and wider pit methods outperformed others, yielding greater above-ground biomass (>70.3 kg tree−1), root biomass (>24.5 kg, tree−1), and cross-sectional area (>3.30 m2 tree−1). These methods also produced longer roots (>4.0 m tree−1) and higher leaf phosphorus (>0.28%) and potassium (>1.81%) levels, fruit juice content (>48.50%), and total soluble solids (>16.05°) compared to other planting methods. This resulted in higher and more sustainable fruit yield production under the trench and wider pit planting methods (>7.21 t ha−1). Similarly, the native and black soil mixture produced healthy fruit trees, improved fruit quality, and sustainably higher fruit yield over the native soil alone. In summary, the trench and wider pit methods (2–3 m3), combined with a soil mixture, are recommended for sustainable, high-quality fruit production in shallow gravelly terrains, thereby improving food security and the livelihoods of farmers in arid regions.

Manipulating Photoconduction in Supramolecular Networks for Solar-Driven Nitrate Conversion to Ammonia and Oxygen.

For photoelectrodes to be used in practical catalytic applications, challenges exist in achieving the efficient production and transport of photogenerated charge-separated states. Analogous concepts in traditional inorganic photoelectrodes can be applied to their organic-polymer counterparts with improved charge-separation efficiencies. In this work, we develop photoconductive organic networks to form a high-performance photoelectrode for NO3- reduction to NH3. In the integrated network, interfaces between the organic electron-donating photoconductor and electron-accepting catalyst can generate charge carriers efficiently upon illumination, leading to enhanced charge separation for photoelectrocatalysis. The photoelectrode network is capable of converting NO3- to NH3 at an external quantum efficiency of 13%. By coupling with a BiVO4 photoanode in tandem, the system reduces NO3- to NH3 and oxidizes H2O to O2 simultaneously at Faradaic efficiencies of 95-98% with sustained photocurrents and production yields. Investigation of the photoconductive network by steady-state/time-resolved spectroscopies reveals the efficient generation and transport of free charge carriers in the photoelectrode, providing a basis for high photoelectrocatalytic performances.

Estimation of life history parameters of the Gangetic leaffish, Nandus nandus from southern coastal waters of Bangladesh: Implications for sustainable management

The Nandus nandus (Hamilton, 1822) is a highly prized food fish that possesses significant nutritional and commercial worth. Bangladesh, India, Pakistan, Malaysia, Myanmar, Thailand and Viet Nam are the countries where it is endemic. The IUCN Bangladesh has classified this species as near endangered due to its current progressive decline. Hence, immediate actions are necessary to efficiently manage the fishery in this country. To address this issue, a comprehensive understanding of its life history parameters is required. This study aimed to examine the growth characteristics, recruitment length, sexual maturity, mortality, exploitation rate, and maximum sustainable production of N. nandus in Bangladesh's southern coastal waters. Samples were taken every month from January through December of 2021. Our study indicates that N. nandus grows in an isometric manner. The estimated asymptomatic length of this species is 18.0 cm in total length (TL), growing at a rate of 1.30 year−1. The growth performance index of this species was determined to be 2.62, and the projected lifespan was calculated to be 2.31 years. The initial length at recruitment was measured to be 9.5 cm TL, whie the size at first sexual maturity was recorded to be 9.4 cm TL. With the contributions of the natural mortality rate (2.26 year−1) and the fishing mortality rate (1.86 year−1) the total mortality rate was found to be 4.12 year−1. The exploitation rate, determined to be 0.45, surpasses the upper limit of sustainable yield criteria set at 0.37. Therefore, it is imperative to implement strategies to avoid excessive fishing and guarantee the long-term control of N. nandus populations.

Assessing pollinator abundance and services to enhance agricultural sustainability and crop yield optimization in the Qilian Mountains

ContextPollination services are critical to crop production and human livelihoods, linking natural ecosystems directly to agricultural production systems. However, pollination services and pollinators are under constant threat from land-use changes and various other environmental pressures. ObjectiveIn this study, employing a case study of the entire Qilian Mountains in northwest China, the distribution of nectar sources in different land use types in the study area was determined through field survey and literature. MethodsBased on 1990–2020 land use data, crop yield data, crop prices, pollinating bee species and nectar plants data. We used the Gross Ecological Product (GEP) accounting and InVEST model of pollination services and assessed the status and trends of pollination services, the risks posed by land use changes and environmental pressures, and suggested potential solutions for mitigating identified risks. Results and conclusionsThe results of the study showed that (1) nectar sources and nesting areas' potential distribution closely correlates with land use types; (2) the Pollinator abundance index (PAI) is above 0.30, a high level, and the Pollination potential index (PPI) is between 0.15 and 0.30, a medium level, with both indices generally increasing over the past 40 years; (3) Human economic activities and land management policies had the most significant impact on pollination services, with 15.57 % and 14.02 %, respectively. Climate change (temperature, precipitation, extreme events) and invasive alien species had relatively minor impacts, accounting for 0.14 % and 0.15 %, respectively. (4) The Qilian Mountains will face a new risk, whether monoculture or the expansion of pollinator-dependent crops could lead to habitat homogenization issues, potentially affecting pollinator abundance and diversity. SignificanceWe recommend that future plans emphasize the provision of pollinator nesting resources along with floral resources, restoration of semi-natural and natural habitats adjacent to crops, adjustment of cropping patterns, and implementation of agricultural diversification, which will help to ensure pollinator diversity and sustainability of agroecosystem pollination services.

Population dynamics of the flathead grey mullet (Mugil cephalus Linnaeus 1758) in the Narmada estuary on the west coast of India

The population dynamics of flathead grey mullet, Mugil cephalus, were evaluated using length-frequency data collected from the Narmada estuary monthly between January 2018 and December 2019. The population parameters were assessed and calculated using the FiSAT-II software tool (FAO-ICLARM Stock Assessment Tools) after the estimation data were divided into 10 mm class intervals. A total of 419 specimens were collected, with an average length range of 171.14±58.15 mm and an average weight of 58.15±45.65 g, respectively. The length-weight relationships were established as W = 0.0105 L2.979. Length-frequency data revealed that length groups 140–149 (15.75 %) and 130–139 mm (13.37 %) dominated the commercial catches of M. cephalus at the Narmada estuary. Different growth parameters were estimated as L∞ = 309.75 mm, K = 0.41 yr−1 and t0 = −0.0013 years. The estimated values of mortality coefficients Z, M, and F were 1.06 yr−1, 0.52 yr−1 and 0.54 yr−1, respectively. The value of exploitation ratio (E) by using the length-converted catch curve method was established as 0.51, which was found to be a little high from the optimum value (0.50). The recruitment was found to be continuous almost throughout the year, with two peaks, once during February to May and another during August to October. The maximum sustainable yield (MSY) was estimated at 970.218 t if the suggested length at first capture (Lc = 123.44 mm TL) is maintained throughout the capture periods. The fishing pressure was found to be slightly excessive for the current stocks, which should be considered for proper management of the fishery in the Narmada estuary.

Combined application of organic and inorganic fertilizers sustained rice yields and N accumulation and decreased soil-canopy system NH3 emission

Excessive inorganic fertilization created various environmental problems, and the combination of organic and inorganic fertilization not only maintains crop production but is also environmentally sustainable. A pot experiment was conducted in Yangzhou, China, to investigate the comprehensive effects of organic fertilization combined with inorganic fertilization on the yield and yield components, nitrogen (N) uptake of different organs, and soil-plant system ammonia (NH3) emissions of two rice cultivars, taking into account the interception of soil NH3 emissions by the rice canopy. The treatments included the conventional practice of inorganic N applied by local farmers (INO, 270 kg N ha−1), 30 % reduced INO (70 %-INO, 189 kg N ha−1), and organic fertilizer combined with 70 %-INO (ORG-INO). Compared to 70 %-INO, ORG-INO significantly increased grain yield by 38 %, mainly due to more panicles. Similarly, ORG-INO also significantly promoted N uptake in the two rice cultivars, especially in terms of grain N accumulation, relative to 70 %-INO. The increase in grain N accumulation caused by ORG-INO was mainly due to enhanced post-anthesis N uptake, rather than N remobilization of vegetative organs, which also suggested that organic fertilizer could modify the processes of N retention and release. There was no significant difference in rice yield and N accumulation between INO and ORG-INO treatments, which also indicated that ORG-INO was effective in maintaining grain yield while reducing inorganic fertilizer input. Moreover, ORG-INO significantly reduced soil-plant system NH3 emissions, while the rice canopy intercepted approximately 30 % of soil NH3 emissions throughout the entire growing season. In summary, ORG-INO treatment significantly reduced the yield-scaled NH3 emissions, and the partial substitution of organic fertilizers for inorganic fertilizers should be recommended to promote environmental sustainability while ensuring food security.

Assessments of 12 Commercial Species Stocks in a Subtropical Upwelling Ecosystem Using the CMSY and BSM Methods

Twelve commercial species exploited in the eastern Guangdong and southern Fujian waters were assessed using the Catch-Maximum Sustainable Yield (CMSY) and Bayesian Schaefer Model (BSM) methods. The carrying capacity (k), intrinsic rate of population growth (r), maximum sustainable yield (MSY), and relative biomass (Bend/k and B/BMSY) were estimated. The current stock status was defined by B/BMSY and fishing mortality (F/FMSY). The results indicate that seven stocks were overfished or below safe biological limits (B/BMSY < 0.5 or F/FMSY > 1), two stocks were in a recovery phase (0.5 < B/BMSY < 1, F/FMSY < 1), and three stocks were under sustainable fishing pressure with healthy biomass, capable of producing yields close to the MSY (B/BMSY > 1, F/FMSY < 1). The stock statuses are consistent with previous studies on the utilization of pelagic fisheries in the eastern Guangdong and southern Fujian waters and with those assessments in other waters. The results of the assessments suggest that these stocks could be expected to produce higher sustainable catches if permitted to rebuild; thus, more effective and proactive management is needed in this upwelling fishing ground.

Performance of length limits to sustain a data- and capacity-limited fishery

Length limit regulations are widely recommended to sustain fish biomass and fishery yields, particularly for data- and capacity-limited fisheries. However, previous findings were generally derived from equilibrium conditions, used hypothetical fisheries, and/or did not explicitly quantify the performance of length limits under a combination of implementation levels, increasing fishing effort, and discard mortality. Here, we apply the management strategy evaluation (MSE) framework to test the performance of three length-limit management procedures (MPs)—maturity and high maturity length limits (i.e., minimum length limits set at and above the length at maturity, respectively) and slot length limit (i.e., excludes both immature and very large fish from retention)—in Iran's largely unregulated, data- and capacity-limited kingfish fishery. We subject these MPs to different conditions, including strong and weak implementations, discard mortality, and an expansion in future fishing efforts, and quantify their overall performance in terms of fishing mortality, biomass, and yield. Our results show that strong implementation of length limits results in the largest gains: the lowest future long-term fishing mortality and the highest biomass and yields relative to the maximum sustainable yield (MSY) level. When illegal-sized fish are selected but discarded with high discard mortality under strong implementation, or retained under weak implementation, the benefits of length limits are severely reduced. Still, length limits are projected to result in much lower fishing mortality and maintain biomass and fishery yields near MSY levels compared to the current fishery's selectivity and retention. Over the entire projection period, the high maturity length limit provided the highest probability of sustainable biomass and the highest mean relative yield under weak implementation and a growing future fishing effort. Our results underscore the benefits of implementing length limit regulation in sustaining data- and capacity-limited fisheries, particularly if current fishing conditions involve selecting and retaining small and immature fish under a high and growing fishing mortality rate.