Perennial Systems Research Articles

Flower arrangement and plant architecture in Atraphaxis, Bactria, and Persepolium (Polygonaceae, Polygonoideae, Polygoneae) and their systematic implications

Plant architecture includes patterns of arrangement of vegetative organs and flowers that may be difficult to describe because of the modular nature of plant growth. We disentangle the terminological issues and provide a case study of a clade of Polygonaceae family. The study focuses on the characteristics of thyrses, reproductive shoots, and shoot systems in 37 species of Atraphaxis, 5 species of Persepolium, and Bactria ovczinnikovii from arid regions of Eurasia using a phylogenetic approach. Based on the plastid phylogeny, parsimonious reconstructions of the evolution of 16 traits were obtained. Three types of perennial shoot systems were identified: perennial systems formed by reproductive (Type I) or vegetative (Type II) shoots, or by both (Type III). Type I was found in Persepolium, Bactria, and a basal subclade of the clade Atraphaxis, and was considered the plesiomorphic state. Type II was found in several distal subclades of the Atraphaxis clade, and was derived from Type I, while Type III was found in a distal subclade, corresponding to the section Atraphaxis. The characteristics of inflorescences and shoots differentiate Persepolium from Bactria and Atraphaxis and provide new data for the classification of the latter genus. Our findings confirm the heterogeneity of the section Tragopyrum, which includes species with Types I and II shoot systems, as well as the isolation of sections Atraphaxis and Physopyrum, which differ in the structure of their thyrses.

Economic Comparison of Stocker Cattle Performance on Winter Wheat vs Summer-Dormant Tall Fescue with Nitrogen or Interseeded Alfalfa in the Southern Great Plains

Abstract Winter wheat (Triticum aestivum L.) is a significant forage source for livestock grazing in the Southern Great Plains (SGP). However, increasing input costs and changing climate conditions compel producers and researchers to search for alternative forage systems, such as cool-season perennials. Specifically, cool-season perennials with summer dormancy traits can survive droughts in the SGP. This paper aimed to determine the net returns of three different types of cool-season perennial summer-dormant tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] systems either with N fertilizer or interseeded with alfalfa (Medicago sativa L.) and the traditional graze-out annual winter wheat forage system. The data were from a 5-year experiment conducted in south-central Oklahoma. Animal performance results indicated that the traditional graze-out winter annual wheat forage system provided more total gains at 434 kg ha-1 than the three tall fescue variety systems at 326 kg ha-1 (p = 0.006) due to more grazing days. Thus, the gross revenue estimated at a cost of gain of $1.60 kg-1 gain for wheat at $694 ha-1 was greater than the average gross revenue of $521 ha-1 for the tall fescue systems. However, the average total cost for the perennial tall fescue systems ($374 ha-1) was lesser than the total cost ($594 ha-1) of the wheat system. Overall, the average net returns were similar for all grazing systems at about $145 ha-1.

Correction: Silvopastoral transitions in Latin America: toward diverse perennial systems

Correction: Silvopastoral transitions in Latin America: toward diverse perennial systems

Jerusalem Artichoke: Nitrogen Fertilization Strategy and Energy Balance in the Production Technology of Aerial Biomass

Jerusalem artichoke (Helianthus tuberosus L.) is a plant with considerable potential for energy generation due to its rapid growth, high biomass yield, and resistance to environmental stresses. The aim of this study was to determine the influence of the nitrogen fertilization strategy on the yield and energy balance in the production technology of Jerusalem artichoke (JA) in a perennial cropping system. The article presents the results of a three-year experiment which was conducted in Poland to determine the effect of different N rates (0, 50, 75, and 100 kg ha−1) supplied with mineral fertilizers and liquid digestate on the energy balance in the production of JA aerial biomass. The experiment had a randomized block design with three replications. The demand for energy in JA cultivation reached 16.2–26.3 (year 1) and 2.9–14.6 GJ ha−1 (years 2 and 3). Energy inputs in the cultivation technology were reduced by 17–19% (year 1) and 35–47% (years 2 and 3) when mineral fertilizers were replaced with digestate. Jerusalem artichoke yields were lowest in the technology without fertilization (12.5 Mg ha−1 DM). Dry matter yield increased significantly (by 43–55%) after the application of 75 kg N ha−1, regardless of fertilizer type. The energy output of biomass peaked (230.1 GJ ha−1) in response to a mineral fertilizer rate of 75 kg N ha−1. In turn, the highest energy gain (218.5 GJ ha−1) was noted after the application of digestate at a rate equivalent to 75 kg N ha–1. The energy efficiency ratio was highest in the technology without fertilization (20.1) and after the application of digestate at a rate equivalent to 75 kg N ha−1 (19.7). Regardless of the factors that limit agricultural production, the energy balance of JA biomass production was most favorable when JA was fertilized with digestate at a rate equivalent to 75 kg N ha−1. The results of this study may pave the way for future research on novel agronomic strategies for sustainable bioenergy production, including nutrient recycling.

An elucidation on productivity, energetics, and carbon footprint of different forage land-use systems in semi-arid tropics of Karnataka, India

Forages are rapid biomass-generating crops that often demand intensive management. They necessitate a clear understanding of energy flow and carbon (C) footprinting which in turn helps in optimization of production resources and environmental impact assessment. Therefore, a field experiment was conducted for five consecutive years (2019–2023) to ascertain eight forage crops’ productivity, energetics, and C footprint. The crops under the annual monoculture system were maize and cowpea. While, Napier, Guinea, Rhodes, Green panic, Anjan grass, and Signal grasses were under perennial monoculture system. The results revealed that, the Napier grass was superior in biological productivity by recording 28%–50% higher green fodder yield over other forages. The energy analysis indicated that the Guinea grass consumed the highest energy (61,719 MJ ha−1 Year−1) during production, while Napier grass showed the highest energy output (32,5991 MJ ha−1 Year−1). Further, Napier grass outperformed the rest in terms of energy use efficiency (5.49), energy productivity (2.39 kg MJ−1), net energy gain (266,641 MJ ha−1 Year−1), energy profitability (4.49), nutrient energy ratio (14.7), and human energy profitability (558). Similar to energy input, Guinea grass production showed the highest C input (970 kg-CE ha−1 Year−1). Whereas, highest C output was observed with Napier grass (56,694 kg-CE ha−1 Year−1) due to its substantial C gain (55,805 kg-CE ha−1), C-efficiency ratio (63.79), and C-stability index (0.98). Consequently, Napier grass can be adopted as a productive, energy profitable, and C-efficient forage crop in semi-arid tropical conditions.

Cultivating connections: Framing turfgrass as a thriving social–ecological–technological system

AbstractTurfgrass systems are some of the most ubiquitous forms of perennial agricultural systems. People interact with them on a daily basis, and they provide a wide variety of social and environmental benefits. Over the past two decades, turfgrass systems have been increasingly seen as coupled human‐natural systems, which has prompted new avenues of research across multiple areas from breeding to management. While this human‐natural systems framework has been helpful, the rapid development and integration of technology (e.g., smart sensors, robotic mowers) and the push for nature‐based solutions and green infrastructure have changed the landscape significantly for turfgrass systems. With this in mind, the current work advocates for the adoption of a new framework, social–ecological–technological systems (SETS), to better understand where turfgrass systems research is situated now and, more importantly, what directions it could go in the future.

485 Impact of annual and perennial forage systems on forage biomass and quality, steer performance, and enteric methane emissions

Abstract Beef producers require forage options that provide adequate yield and high nutritive value, optimizing the production and sustainability of grazing operations. Few multiple year studies within Canada compare novel perennial and annual grass legume blends under grazing. This study evaluated the effects of perennial and annual forage systems on forage biomass and quality, grazing animal performance, and enteric emissions. Forage treatments included 1) AC Success hybrid bromegrass (Bromus riparius Rehm. × Bromus inermis Leyss.) + PS3006 alfalfa (Medicago sativa L.; HBG-ALF), 2) AC Armada meadow bromegrass (Bromus riparius Rehm.) + AAC Mountainview sainfoin (Onobrychis viciifolia Scop.; MBG-SF), 3) AC Hazlet fall rye (Secale cereale L.) + Frosty berseem clover (Trifolium alexandrinum L.; FR-CLOV), and 4) Winfred forage brassica (Brassica oleracea L.× Brassica rapa L.) + Gorilla forage brassica (Brassica napus L.) + 4010 pea (Pisum sativum L.) + CDC Austenson barley (Hordeum vulgare L.; BR-PE-BRAS). Yearling beef steers [n = 120, body weight (BW) = 397 ± 10 kg] were randomly allocated to 1 of 4 replicated (n = 3) forage systems for an average of 65 d grazing period amongst the 12 paddocks. Dry matter yield (DMY) was similar (P = 0.33) between BR-PE-BRAS (2,170 kg/ha) and HBG-ALF (1938 kg/ha), which were greater (P < 0.0001) than both MBG-SF (1030 kg/ha) and FR-CLOV (700 kg/ha) systems. Total digestible nutrient content (TDN) of FR-CLOV (63.6%) and BR-PEA-BRASS (62.0%) was greater (P < 0.0001) than both MBG-SF (51.7%) and HBG-ALF (49.3%) forages. Crude protein (CP) was greatest in FR-CLOV (15.2% P = 0.0012) intermediate in BR-PEA-BRASS (10.0%) and HBG-ALF (8.5%), and least in MBG-SF (6.6%). Steer performance was greatest when grazing HBG-ALF (87 kg/ha) paddocks, which was similar (P = 0.31) to FR-CLOV (62 kg/ha) and similar (P = 0.10) MBG-SF (51 kg/ha), but greater (P = 0.01) than BAR-PEA-BRASS (26 kg/ha). Enteric methane concentration from steers was the least when grazing BR-PE-BRAS (19.7g/kg DMI), followed by FR-CLOV (22.4g/kg DMI), MBG-SF (23.4g/kg DMI) and finally HBG-ALF (28.1g/kg DMI). In summary, BR-PE-BRAS and HBG-ALF forage systems provided the greatest DMY, while steer average daily gain (ADG) grazing HBG-ALF forage outperformed steers on BR-PE-BRAS paddocks. Forage energy and protein was greater in annual forage systems FR-CLOV and BR-PE-BRAS, compared with perennial forage systems. Enteric methane levels were the lowest in the steers grazing BR-PE-BRAS forage.

Decade-long effects of integrated farming systems on soil aggregation and carbon dynamics in sub-tropical Eastern Indo-Gangetic plains

Integrated farming system (IFS) aims to diversify the agricultural landscapes by incorporating different components to meet the multifarious needs of the burgeoning population. The present study was undertaken to understand the impact of different cropping systems on soil organic carbon (SOC) stock, aggregate distribution, and aggregate associated organic carbon (AAOC) in 2-IFS models of varying sizes (0.4 and 0.8 ha) established during 2008–2009. After 10 years of the study, the fodder system registered the greatest TOC and carbon stocks across IFS models, with surface soil (0–15 cm) accumulating 17 and 13% higher TOC and C stock, respectively, in 0.4 and 0.8 ha models. In 0–15 cm, macroaggregates (Ma) represented the highest proportion (75–76%) in both models. Among cropping systems, the fodder system recorded the highest large macroaggregates in both IFS models. Within 0–30 cm depth, small macroaggregates are mostly found in the perennial system (fodder, guava+turmeric, and lemon intercropping system), indicating the potential to improve the aggregate stability over the seasonal (shorter duration) system. In general, micro aggregate (Mi) fraction was pre-dominant in sub-surface soil (17.35%). The maximum AAOC was found in Ma compared to Mi fractions, with approximately 67 and 63% of total carbon associated with Ma in 0.4 and 0.8 ha IFS models, respectively. Interestingly, the 0.8 ha IFS model had higher TOC (~11%) and carbon stock (~12%) than the 0.4 ha model, but AAOC did not show a similar result, indicating the influence of cropping systems on AAOC. The study indicated that the fodder-based production system had better performance in terms of soil physical health and increased aggregate stability and content of soil carbon. This is indicative of the advantages of perennial-based systems over seasonal- or annual-based cropping systems for soil sustainability in Eastern Indo-Gangetic Plains.

Optimization of Manning's roughness coefficient using 1-dimensional hydrodynamic modelling in the perennial river system: A case of lower Narmada Basin, India.

This research bears significant implications for river management, flood forecasting, and ecosystem preservation in the Lower Narmada Basin. A more precise estimation of Manning's Roughness Coefficeint (n) will enhance the accuracy of hydraulic models and facilitate informed decision-making regarding flood risk management, water resource allocation, and environmental conservation efforts. Ultimately, this study aspires to contribute to the sustainable management of perennial river systems in India and beyond by offering a robust methodology for optimizing Manning's n tailored to the complex hydrological dynamics of the Lower Narmada Basin. Through a synthesis of empirical evidence and computational modelling, it seeks to empower stakeholders with actionable insights toward preserving and enhancing these invaluable natural resources. Using the new HEC-RAS v 6.0, a one-dimensional hydrodynamic model was developed to predict overbank discharge at different points along the basin. The study analyzes water levels, stream discharges, and river stage, optimizing Manning's n and required flood risk management. The model predicted a strong output agreement with R2, NSE, and RMSE for the 2020 eventas 0.83, 0.81, and 0.36, respectively, with an optimum Manning's n of 0.03. The lower Narmada Basin part near the coastal zone (validation point) appears inundated frequently. The paper aims to provide insights into optimizing Manning's coefficient, which can ultimately lead to better water flow predictions and more efficient water management in the region.

Tailoring defoliation and nitrogen management for large canopy radiation use and biomass production of perennial systems destined for biorefinery

Perennial leafy grasses and legumes are promising for extraction of proteins with a green biorefinery amid increasing demand for local production. However, which defoliation strategy increases radiation-use efficiency and biomass production still needs to be determined. A multi-year field experiment started in 2019 in Denmark with fertilized grasses (perennial ryegrass, tall fescue), unfertilized legumes (alfalfa, red clover) and their fertilized mixture (grass-legume), each defoliated at 2-, 4- or 8- weeks interval, at either 7-9 or 12-14 cm defoliation height. The main aim was to quantify effects of species, defoliation height and frequency, and nitrogen application rate on canopy radiation interception, aboveground biomass and crude protein production, as well as aboveground radiation use efficiency (RUEA).The results showed that accumulated intercepted photosynthetically active radiation (AIpar) increased with increasing defoliation height and decreasing frequency for most systems, with the largest AIpar obtained seasonally by red clover (730-815 MJ m−2) and grass-legume mixture (790-826 MJ m−2) defoliated at medium to low frequency. Tall fescue defoliated at medium to low frequency yielded the highest aboveground biomass (10-14 Mg ha−1) and red clover defoliated at medium to high frequency yielded the most crude protein (2.5-2.9 Mg ha−1) compared to all other systems annually. RUEA decreased with increasing defoliation height and maximum values were achieved at medium frequency, with tall fescue having significantly higher RUEA (1.6-2.1 g MJ−1) than the other systems. Seasonally, RUEA was variable at high defoliation frequency, being consistently higher at the start and the end of the season for ryegrass and the mixture systems.This study pinpoints tall fescue and red clover as perennial crops with high agronomic productivity among tested species for green biorefinery and also concluded that red clover in temperate humid climate maximize productivity and sustainability for biorefining with defoliation at low height and medium frequency.

A molecular approach to unravel trophic interactions between parasitoids and hyperparasitoids associated with pecan aphids.

Advances in molecular ecology can overcome many challenges in understanding host-parasitoid interactions. Genetic characterization of the key-players in systems helps to confirm species and identify trophic linkages essential for ecological service delivery by biological control agents; however, relatively few agroecosystems have been explored using this approach. Pecan production consists of a large tree perennial system containing an assortment of seasonal pests and natural enemies. As a first step to characterizing host-parasitoid associations in pecan food webs, we focus on aphid species and their parasitoids. Based on DNA barcoding of field-collected and reared specimens, we confirmed the presence of 3 species of aphid, one family of primary parasitoids, and 5 species of hyperparasitoids. By applying metabarcoding to field-collected aphid mummies, we were able to identify multiple species within each aphid mummy to unravel a complex food web of 3 aphids, 2 primary parasitoids, and upward of 8 hyperparasitoid species. The results of this study demonstrate that multiple hyperparasitoid species attack a single primary parasitoid of pecan aphids, which may have negative consequences for successful aphid biological control. Although further research is needed on a broader spatial scale, our results suggest multiple species exist in this system and may suggest a complex set of interactions between parasitoids, hyperparasitoids, and the 3 aphid species. This was the first time that many of these species have been characterized and demonstrates the application of novel approaches to analyze the aphid-parasitoid food webs in pecans and other tree crop systems.

Evolution of Neoproterozoic siliciclastic Kerur Formation in the light of sequence stratigraphic framework: Badami Basin, Karnataka, India

Field-based sedimentology, state of the art facies analysis and sequence stratigraphic framework analysis have revealed the controls of local and global tectonics, basin-marginal slope, climate and changes in relative sea level (RSL) over the sedimentation pattern and evolution of a Neoproterozoic Kerur Formation within the Badami Group of Kaladgi Supergroup in India. The entire succession shows three major cycles of deposition. Facies study and fluvial architectural elemental analysis suggest considerable variations in depositional environments as well as palaeogeography. A transition from basin-margin alluvial cone deposits to braided system, initially with fluctuating ephemeral flows then to a steadier semi-perennial nature, is discernible within the 1st cycle, in response to decreasing depositional slope with rising water table. The initial alluvial cone and braided ephemeral streams of high slope areas is designated as a product of low accommodation systems tract (LAST), while the semi-perennial system with steadier flows, representing the axial river of the initial rift valley, appears to be a product of high – accommodation systems tract (HAST). The 2nd cycle begins with a perennial and steady braided river system and grades upward to a shallow marine succession, comprising wave-dominated, well-sorted sandstone, with a granular transgressive lag at the base. Thus, the bottommost fluvial interval of the 2nd cycle constitutes the lowstand systems tract (LST). The marine succession represents deposits of outer shelf offshore to foreshore-beach settings and is composed of an initially deepening and fining upward transgressive systems tract (TST), followed by a coarsening and shallowing upward highstand systems tract (HST) with a maximum marine flooding surface (MFS) in between, demarcated by a shale-rich condensed zone. The 3rd cycle, with its prograding alluvial fan and aggrading braided fluvial deposits and restricted occurrence, represents only the low accommodation systems tract (LAST) with a subaerial unconformity at the base. The basin evidently initiated in the western sector, followed by its eastward expansion during the first major rejuvenation of the basin margin faults, after the deposition of the 1st cycle. After the basin-wide deposition of the 2nd cycle, restricted development of the 3rd cycle took place in the western sector only, following the second major rejuvenation of the fault system. The proposed sedimentological model, supported by established geochronological constraints, suggests that the sedimentation in the 1st cycle begins with scree cones, alluvial fans and braided ephemeral channel networks, originated from faulted basin margins within a riftogenic setting possibly related to the global-scale extensional tectonics of Rodinia breakup. After the expansion of the basin, the marine inundation has been correlated to the transgression that possibly took place during the post-rift maturation stages.

Silvopastoral transitions in Latin America: toward diverse perennial systems

AbstractAgroecosystems with greater diversity and perenniality have been proposed to promote resilience to climate change, stability of production, multiple ecosystem services, and socioeconomic outcomes. A wide diversity of silvopastoral systems have been promoted in Latin America for their production and environmental outcomes. In this brief perspective article, we discuss the implications of different trajectories towards silvopastoral systems within the framework of ecological intensification. Transitioning from agricultural systems dominated by annual crops towards complex silvopastoral systems integrating multiple perennial species and livestock constitutes a clear trajectory of ecological intensification. In the context of the tropical dry forests and Amazon rainforests, re-introducing native trees into degraded sown pastures to establish silvopastoral systems increases biodiversity, perenniality, and ecosystem services. In contrast, in the context of native grasslands, plantations of exotic trees for timber or silvopastoral systems reduce biodiversity and ecosystem services. Therefore, transitioning to silvopastoral systems is not always a trajectory of ecological intensification but depends on the contexts and native ecosystems.

The carcass characteristics and quality of meat from lambs grazing perennial wheat with different companion legumes (clover, serradella, lucerne) or a mineral supplement

This study compared carcasses as well as the quality and mineral concentration of meat from lambs extensively grazing perennial wheat with clover (PW + C), serradella (PW + S), lucerne (PW + L), or a mineral salt supplement (PW + Min). A split-plot design was used, wherein 3 crossbred ewe lambs (n = 72 in total) (sub-plots) grazed each of 4 forage types (plots), that were replicated across 6 locations (blocks). The feeding study concluded after 96 d, when all the lambs were slaughtered. The left longissimus lumborum muscles (LL) were collected and wet aged for either 5 or 56 d post-mortem. Lambs grazing PW + Min were found to produce carcasses with lower dressing percentage values to those grazing the other forage types (P = 0.037). The LL of lambs grazing PW + L had the lowest crude protein values (P = 0.015). Forage type by ageing period interactions did not affect meat quality. The 56 d ageing period resulted in higher purge loss (P < 0.001) and TVB-N values (P < 0.001) and a decline in shear force (P < 0.001) compared to the 5 d ageing period. The other carcass and meat quality parameters were not affected by forage type; including hot carcass weight, pH decline parameters, eye muscle area, cooking loss, intramuscular fat, sarcomere length, colour stability, and concentrations of calcium, iron, magnesium, sodium, and zinc in the LL. These findings confirm that perennial cereal production systems, that include legume forages with contrasting protein, energy, and micronutrient profiles, can deliver comparable lamb carcasses and meat quality.

Jerusalem Artichoke: Energy Balance in Annual and Perennial Cropping Systems—A Case Study in North-Eastern Poland

This article presents the results of a three-year experiment (2018–2020) conducted at the Agricultural Experiment Station in Bałcyny (north-eastern Poland) with the aim of determining Jerusalem artichoke (JA) yields and the energy balance of biomass production in (i) a perennial cropping system (only aerial biomass was harvested each year) and (ii) an annual cropping system (both aerial biomass and tubers were harvested each year). When JA was grown as a perennial crop, the demand for energy reached 25.2 GJ ha−1 in the year of plantation establishment and 12.3–13.4 GJ ha−1 in the second and third year of production. The energy inputs associated with the annual cropping system were determined in the range of 31.4–37.1 GJ ha−1. Biomass yields were twice as high in the annual than in the perennial cropping system (20.98 vs. 10.30 Mg DM ha−1). Tuber yield accounted for 46% of the total yield. The energy output of JA biomass was 1.8 times higher in the annual than in the perennial cropping system (275.4 vs. 157.3 GJ ha−1). The average energy gain in JA cultivation ranged from 140 (perennial crop) to 241 GJ ha−1 (annual crop). The energy efficiency ratio of JA biomass production reached 7.7–13.3 in the perennial cropping system, and it was 20% lower in the annual cropping system. These results imply that when JA was grown as an annual crop, an increase in energy inputs associated with plantation establishment (tillage and planting) and the harvest and transport of tubers was not fully compensated by the energy output of tubers.

Early impacts of marginal land‐use transition to Miscanthus on soil quality and soil carbon storage across Europe

AbstractMiscanthus, a C4 perennial rhizomatous grass, is a low‐input energy crop suitable for marginal land, which cultivation can improve soil quality and promote soil organic carbon (SOC) sequestration. In this study, four promising Miscanthus hybrids were chosen to evaluate their short‐term potential, in six European marginal sites, to sequester SOC and improve physical, chemical, and biological soil quality in topsoil. Overall, no differences among Miscanthus hybrids were detected in terms of impacts on soil quality and SOC sequestration. SOC sequestration rate after 4 years was of +0.4 Mg C ha−1 year−1, but land‐use transition from former cropland or grassland showed contrasting SOC sequestration trajectories. In unfertilized marginal lands, cultivation of high‐yielding Miscanthus genotypes caused a depletion of K (−216 kg ha−1 year−1), followed by Ca (−56 kg ha−1 year−1), Mg (−102 kg ha−1 year−1) and to a lesser extent of N. On the contrary, the biological turnover of organic matter increased the available P content (+164 kg P2O5 ha−1 year−1). SOC content was identified as the main driver of changes in biological soil quality. High input of labile plant C stimulated an increment of microbial biomass and enzymatic activity. Here, a novel approach was applied to estimate C input to soil from different Miscanthus organs. Despite the high estimated plant C input to soil (0.98 Mg C ha−1 year−1), with significant differences among sites and Miscanthus hybrids, it was not identified as a driver of SOC sequestration. On the contrary, initial SOC and nutrients (N, P) content, as well as their elemental stoichiometric ratios with C, were the key factors controlling SOC dynamics. Introducing Miscanthus on marginal lands impacts positively soil biological quality over the short term, but targeted fertilization plans are needed to secure crop yield over the long term as well as the C sink capacity of this perennial cropping system.

Crop diversification in perennial plantation systems of Sri Lanka: Patterns, determinants and challenges

CONTEXTThe adoption of crop diversification in response to climate change in perennial cropping systems is poorly understood. OBJECTIVEThis study identifies the current level of diversification, determinants of and constraints to adopting crop diversification in tea plantations in Sri Lanka as an example of a perennial crop in a developing country context. METHODSWe use a Panel Tobit model to analyse the driving forces of crop diversification using 2004–2018 data collected from 49 tea estates. In addition, tea estates' managers were interviewed to investigate barriers to adopting crop diversification. RESULTS AND CONCLUSIONSThe study reveals that geo-climatic conditions, magnitude of increase in temperature, and higher revenue variability are the specific factors influencing managers' probability of adopting crop diversification. Constraints to crop diversification include technological lock-in hindering alternative crops and worker shortages, financial difficulties, lack of productive lands suitable for alternative crops, ineffective Government land-use policies and regional weather patterns such as prolonged rainfall and heavy winds. SIGNIFICANCEIdentified barriers provide important insights into how to assist plantations to adopt crop diversification. We propose three policy recommendations to enhance tea estate managers' adaptive capacity to various environmental and social changes through crop diversification. These are: (1) enable managers to acquire the technical know-how on cultivating alternative crops by conducting practical training programmes connecting with the Department of Agriculture or Agriculture Faculties of regional Universities.; (2) increase awareness of less labor-intensive crops for diversification along with strategies for mechanisation via programmes integrated with the Ministry of Plantation Agriculture and the Agriculture Modernization Project of the Department of Agriculture; and (3) enact a national policy to mandate crop diversification in marginal tea lands with financial assistance from the Government.

Ecotoxicological evaluation of surface waters in Northern Namibia

The increasing pressure on freshwater systems due to intensive anthropogenic use is a big challenge in central-northern Namibia and its catchment areas, the Kunene and the Kavango Rivers, and the Cuvelai-Etosha Basin, that provide water for more than 1 million people. So far, there is no comprehensive knowledge about the ecological status and only few knowledge about the water quality. Therefore, it is crucial to learn about the state of the ecosystem and the ecological effects of pollutants to ensure the safe use of these resources. The surface waters of the three systems were sampled, and three bioassays were applied on three trophic levels: algae, daphnia, and zebrafish embryos. Additionally, in vitro assays were performed to analyze mutagenicity (Ames fluctuation), dioxin-like potential (micro-EROD), and estrogenicity (YES) by mechanism-specific effects. The results show that acute toxicity to fish embryos and daphnia has mainly been detected at all sites in the three catchment areas. The systems differ significantly from each other, with the sites in the Iishana system showing the highest acute toxicity. At the cellular level, only weak effects were identified, although these were stronger in the Iishana system than in the two perennial systems. Algae growth was not inhibited, and no cytotoxic effects could be detected in any of the samples. Mutagenic effects and an estrogenic potential were detected at three sites in the Iishana system. These findings are critical in water resource management as the effects can adversely impact the health of aquatic ecosystems and the organisms within them.

Earthworm communities and their relation to above‐ground organic residues and water infiltration in perennial cup plant (Silphium perfoliatum) and annual silage maize (Zea mays) energy plants

AbstractPerennial energy cropping systems are hailed as a sustainable way of mitigating and potentially adapting to climate change. As a result of the absence of tillage, soils cropped with perennials like cup plant (Silphium perfoliatum) promote abundant and functionally diverse earthworm communities. Hence, ecosystem service provision because of earthworm activity and functional redundancy, for example, litter decomposition, water infiltration and nutrient turnover, is considerably enhanced in perennial cropping systems. We studied the abundance and functional role of earthworms in non‐tilled perennial systems and reduced‐tilled annual systems to assess their relationship with the respective above‐ground organic residues and their implications for the soil water dynamic. We sampled earthworms and simultaneously measured the saturated infiltration rate for two consecutive years in cup plant and maize (Zea mays) fields. Furthermore, we sampled above‐ground litter each trimester in both systems and analysed the total C and N content and CN ratios. Our field investigations revealed significantly higher earthworm abundance, species diversity and richness in cup plant systems likely because of the absence of tillage and the formation of a litter layer. High abundances of juveniles in both maize and cup plant systems pointed to harsh habitat conditions likely because of temperature variations, waterlogging and bulk density. The respective field litter was of minor importance as a food source in both systems because of poor quality, but may positively affect the soil water balance in cup plant systems. Earthworm populations in maize may have been supported by organic fertilizer while earthworm populations in cup plants may have additionally benefitted from the extensive root network and a higher on‐site plant diversity. Reduced tillage regimes in maize systems may have enhanced saturated infiltration rates. A direct link between earthworms and infiltration was not validated, but may not be excluded in the future, as earthworm populations may develop slowly because of adverse habitat conditions. Our results show that perennials support abundant and diverse earthworm populations and indicate the importance of functional redundancy and the diversity of food sources. The combination of both earthworm abundance and perennial cropping systems is capable of increasing on‐site ecosystem stability and supporting adaptation to climate change by increasing functional redundancy and, ultimately, providing ecosystem services. The noticeable occurrence of the latter, however, may be delayed because of the slow establishment of earthworm communities and delayed build‐up of ecosystems stability. Hence, a transitional phase is inevitable to reap the benefits of perennial energy cropping systems and must be accounted for.

Production and socio-economic contribution of bitter kola (Garcinia kola) to people’s livelihood in Ifedore Local Government, Ondo State, Nigeria

This study evaluates the production and socio-economic contribution of bitter kola (Garcinia kola) to the livelihood of the people in Ifedore Local Government, Ondo State. The study was conducted in six villages purposively selected in the Local Governments. A total of sixty pre-tested questionnaires were randomly administered to respondents in the study area. The study revealed that 37% of the respondents are above 50 years old while 42% and 58% are male and female respectively with 42% having primary education. The study also revealed that 48% of respondents operate farm sizes of between 11-20 hectares of land with 37% having farming experience of 11-20 years. The majority (92%) of the respondents grow Garcinia kola in mixed plantations while 8% collect their products from natural forests. Seventy-eight percent of the respondents produce 1-5 bags of 50 kg per year, while 35% made between ₦51,000 - ₦100,000 annually. The study shows that 33.7% of the respondents use Garcinia kola for medicinal and social/cultural purposes respectively. It was recommended that government should encourage farmers through incentives such as interest-free loans for large-scale production of bitter kola in plantations through a perennial crop combination agroforestry system for local and international markets.