Monoculture Research Articles

The effects of monoculture and intercropping on photosynthesis performance correlated with growth of garlic and perennial ryegrass response to different heavy metals

BackgroundThe potential of phytoremediation using garlic monoculture (MC) and intercropping (IC) system with perennial ryegrass to enhance the uptake of cadmium (Cd), chromium (Cr), and lead (Pb) were investigated.ResultsPositive correlations were found between MC and IC systems, with varying biomass. Production of perennial ryegrass was affected differently depending on the type of toxic metal present in the soil. Root growth inhibition was more affected than shoot growth inhibition. The total biomass of shoot and root in IC was higher than MC, increasing approximately 3.7 and 2.9 fold compared to MC, attributed to advantages in root IC crop systems. Photosystem II efficiency showed less sensitivity to metal toxicity compared to the control, with a decrease between 10.07–12.03%. Among gas exchange parameters, only Cr significantly affected physiological responses by reducing transpiration by 69.24%, likely due to leaf chlorosis and necrosis.ConclusionThis study exhibited the potential of garlic MC and IC with perennial ryegrass in phytoremediation. Although the different metals affect plant growth differently, IC showed advantages over MC in term biomass production.

Use of PGPR (Plant Growth Promoting Rhizobacteria) to Increase Yields of Cayenne Pepper (Capsicum frutescens L.) in Monoculture Planting Systems and Under the Shade of Mature Citrus Plants

Cayenne pepper is a vegetable commodity, which can be categorized as a commercial commodity and has the potential to be developed. The problem that arises is that more and more agricultural land is getting damaged. One effort to overcome this problem is to use organic fertilizers such as PGPR. The purpose of this study was to obtain the optimum dose of PGPR (Plant Growth Promoting Rhizobacteria) on the growth and yield (quantity and quality) of cayenne pepper in a monoculture cropping system and under the shade of mature citrus trees. The research was conducted in a Citrus Orchard, Tegalgondo Village, Karangploso District, Malang Regency. The time of the research was carried out in December 2022 - March 2023. This study used a Randomized Block Design (RBD) with two factors, namely the concentration of PGPR (Plant Growth Promoting Rhizobacteria) and the planting system. The first factor is the treatment of the application of the planting system which consists of 2 levels, namely MN (Monoculture) TS (Under the Orange Shade). The second factor was the treatment of PGPR concentration consisting of 4 levels, namely, P0 (without PGPR), P10 (10 ml.-1 concentration), P20 (20 ml.-1 concentration), P30 (30 ml.-1 concentration) and Treatment randomized in each group. and cropping system treatment. The results showed that there was no real interaction between the cropping system and PGPR on the growth of cayenne pepper plants. This is because there is a different effect on each treatment.

Evaluation of marandu palisadegrass regrowth intervals in silvopastoral and monoculture systems

Silvopastoral systems (SPS) offer a sustainable alternative for animal production in tropical ecosystems. This study aimed to evaluate the effects of deferment days on herbage accumulation, plant-part composition, and canopy structural characteristics of Marandu palisadegrass (Urochloa brizantha Hochst. ex A. Rich.) in SPS with Eucalyptus urophylla and monoculture (MC). The experiment was conducted using a randomized block design, with each system individually allocated at the center of each plot in a 3 x 4 factorial arrangement, consisting of three systems: monoculture, and silvopastoral systems with tree row spacings of 12 m and 18 m, and tree intra-row spacing of 2 m, across four regrowth periods (60, 90, 120, and 150 days), each with three replications. Increasing deferment days reduced the proportion of green components in the forage, affecting tiller population density (TPD), leaf dry mass (LDM), and leaf/stem ratio. Maximum LDM production occurred at approximately 88 days with 0.63 Mg ha-1, while peak green dry mass (GDM) was at 94 days, reaching 1.11 Mg ha-1. Both dead material dry mass (DMDM) and total dry mass (TDM) increased linearly with regrowth periods, although TDM comprised about 47% dead forage. A regrowth period of 94 days from March is feasible for Marandu palisadegrass in SPS with 12 m and 18 m between tree rows, demonstrating that this spacing does not hinder forage production.

Abstract 284: Crosstalk with postmenopausal obese mammary adipocytes impacts breast cancer cell metabolism and promotes tumorigenesis

Abstract Introduction: Obesity is associated with an increased risk and a poor prognosis of breast cancer (BC) in postmenopausal (PM) women. The mechanism(s) underlying obesity-related PM BC are not clearly understood. We hypothesized that the increased local presence of ‘obese’ mammary adipocytes within the breast tumor microenvironment (TME) promotes the acquisition of an invasive BC cell phenotype and markedly accelerates tumor proliferation and progression. Methods: We asked whether cancer-associated mammary adipocytes (CA-MAd) differ from normal mammary adipocytes (N-MAd) in their ability to promote tumorigenesis of dormant BC cells and if so, what the underlying mechanism(s) might be. Using a 2D transwell model, BC cells (ER- and ER+), were cocultured with obese PM CA-MAd isolated from breast cancer patients or obese mammary N-MAds from PM disease-free women and analyzed for migration, proliferation, phenotypic, signaling and metabolic alterations. Results: Compared to monoculture (MC) conditions, BC cells cocultured (CC) with CA-MAd displayed significantly increased migration and proliferation. Quantitative phase imaging indicated that CA-MAd secretome-treated BC cells displayed increased motility, speed, distance covered and cell size/area compared to N-MAd. Consistent with these results, mesenchymal markers such as fibronectin, vimentin and SNAIL were upregulated whereas the epithelial marker E-cadherin was downregulated in CC vs. MC conditions suggesting that Ads in the TME promote EMT in BC cells. Interestingly, mature Ads CC with BC cells underwent delipidation and dedifferentiation as indicated by reduced Oil Red staining, decreased lipid content and reduced expression of Ad maturation markers such as FABP4, ADIPOQ and PLIN1. Consistently, we determined that CC BC cells exhibited increased lipid uptake and BODIPY staining and upregulated pAMPK, pACC and CPT1A signaling when compared to MC BC cells. Short term treatment of BC cells with both N-MAd and CA-MAd secretomes resulted in increased oxygen consumption rate (OCR), basal respiration, ATP-linked respiration and proton-linked respiration compared to control and as determined by the Seahorse extracellular flux assay. CC with MAds significantly downregulated OCR and all respiration parameters in BC cells suggesting decreased glucose uptake and glycolytic flux. Conclusions: Compared to MC, CC with obese M-Ads promoted functional, phenotypic and metabolic changes in BC cells. Taken together, our results indicate that crosstalk between BC cells and obese MAds promotes delipidation of MAds and a concomitant lipid uptake in BC cells and a switch to lipid metabolism signaling pathways that may, in turn, drive a metabolic shift in BC cells and promote tumor growth. [Supported by NIH RO1CA185530, the Breast Cancer Research Foundation, the Karp Family Foundation and the Nile Albright Research Foundation] Citation Format: Roopali Roy, Rama Aldakhlallah, Stephen Cobbs, Emily Man, Caleb Hallinan, Kwonmoo Lee, Margaret Lotz-Bousvaros, Susan Pories, Marsha A. Moses. Crosstalk with postmenopausal obese mammary adipocytes impacts breast cancer cell metabolism and promotes tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 284.

Capim marandu sob diferimento em monocultivo e sistema silvipastoril: composição bromatológica e mineral

Abstract This study aimed to evaluate the chemical and mineral characteristics of Marandu grass under stockpiling in monoculture (MC) and a silvopastoral system (SPS) with 12- (SPS12) and 18-m (SPS18) spacing between tree rows. The experimental design consisted of randomized blocks, in which each system was allocated individually. Each treatment was formed in the center of each plot in a 3 × 4 factorial arrangement consisting of three systems (MC and SPS12 and SPS18 between the tree rows) and four stockpiling periods (60, 90, 120, and 150 days), totaling 12 treatments with three replications. No interaction effect was observed between the factors (p>0.05) for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), phosphorus (P), potassium (K), calcium (Ca), or magnesium (Mg). The CP content decreased with increasing stockpiling days but met the suggested requirement for ruminants up to 75 days. The NDF and ADF concentrations increased, while P and K contents decreased with increasing stockpiling days. Magnesium and Ca concentrations did not differ with stockpiling days. However, a difference was observed only for Mg relative to the evaluated systems, which was higher in MC and SPS12, differing from SPS18. The spacing adopted in the SPS of 12 and 18 m does not negatively influence the nutritional value of the forage plant. The 75-day stockpiling period from March favored the concentration of macronutrients and CP content in Marandu grass in both MC and SPS.

Diversified cropping systems effect on the water status of mandarin trees under deficit irrigation

The diversified cropping systems has several environmental benefits, but there is no certainty about their effect on the water status of trees, especially in areas with permanent low availability of irrigation water. Therefore, our objective was to evaluate the effect of the establishment of diversified cropping systems in a traditional monoculture (MC) of adult mandarin trees on its water status and yield under sustained deficit irrigation (SDI) and regulated deficit irrigation (RDI). Six treatments were tested during three consecutive seasons: (i) a mandarin monoculture under SDI (MC-SDI), with permanent bare alleys and irrigated at ∼70 % ETc during the entire season (actual amount of irrigation water available in the area); (ii) a diversified mandarin crop (D1-SDI), irrigated as MC-SDI, with a rotation of fava bean and barley/vetch in the alleys; and (iii) a second diversified mandarin crop (D2-SDI), irrigated as MC-SDI, with a seasonal rotation of fava bean, purslane and cowpea. Additionally, three RDI treatments were evaluated, denoted as (iv) MC-RDI, (v) D1-RDI and (vi) D2-RDI, irrigated as MC-SDI, except during the stage II of fruit growth, when it was reduced by 50 % with an irrigation threshold of a solar midday stem water potential of ∼ –1.5 MPa. The mandarin yield was not affected by the effect of diversified cropping systems, but the RDI reduced it on average by 30.1 % with respect to SDI. The alley cropping of fava bean and barley/vetch during winter and spring under sustained deficit irrigation conditions reduced the water stress intensity of mandarin trees by 26.9 % over the entire season, while cultivation of purslane or cowpea during summer increased it by 60–144 %. Both diversifications required a greater amount of water than the monoculture, in these terms an additional reduction in the irrigation of mandarin trees, as in the RDI treatment, allowed to solve this additional water requirement, but promoted an increase in the water stress intensity of the trees, which may affect their productivity in the mid and long-term.

The potential of floating macrophytes as feed and phytoremediation resources to improve the environmental performance of giant gourami production in Indonesia: A life cycle assessment

Over the past few decades, Indonesian freshwater aquaculture has intensified, raising many issues on the associated environmental impacts. In this study, a life cycle assessment (LCA) was used to assess the environmental performance of Indonesian giant gourami (Osphronemus goramy) aquaculture. We compared two contrasting fish production systems: a traditional monoculture (MoC) or a co-culture with the macrophyte Azolla filiculoides used as feed alternative to compounded pellets (CoC). Seven impact categories were considered: climate change, eutrophication, cumulative energy demand, land occupation, acidification, net primary production use (NPPU) and water dependence. The potential impacts were calculated in terms of 1 kg of fish produced by the systems and were also expressed in terms of surface area (m2 of the farm). Monte Carlo analysis was carried out to evaluate uncertainties in the assessed impacts based on data uncertainties for the systems. Results highlighted notable differences between the two production systems. CoC led to less impact relative to climate change, eutrophication and NPPU per kg of fish produced. These differences were even greater when reporting the impacts per surface area. Nonetheless, the main contributors of the seven impact categories remained constant between the two production systems (CoC and MoC). Overall, our findings suggested that using floating macrophytes as alternative feed resources, even in relatively low proportions, can improve the environmental performance of giant gourami production.

Impacts of intercropping on the major insect pests of <i>Jatropha curcas L.</i> in south of Benin

Jatropha curcas is an oleaginous plant whose seed yield is low. The present study aimed at evaluating is pests associated with J. curcas. In regards to the densities, Denticera near divisella density was obtained 0.85 larvae per plant in J. curcas in sole farming and 0.70, 0.61, 0.85 larvae respectively when intercropped with casava, maize and cowpea. When J. curcas was intercropped with cassava Stomphastis thraustica was the most encountered species with a density of 1.28 larvae per plant while 0.61 larvae density was encountered for intercropped with maize and 0.27 larvae density with cowpea against 0.43 larvae in mono culture. For J. curcas with maize, Aulacophora africana was the most abundant species with a density of 0.47 adult per plant. In the case of J. curcas with cowpea. D. nr divisella had the highest density of 0.85 larvae per plant. It was also shown that the grain yield of J. curcas depends of intercrop. The yields were from 591.75 ± 109.25kg / ha; 431.75 ± 92.50kg / ha; 252.50 ± 51.50kg / ha; 89.50 ± 43.00kg/ha respectively in pure farming of J. curcas, Jatropha intercropped with maize, cowpea or cassava respectively. Therefore, it is important to choose intercropping to reduce the density of pests in Jatropha crop.

Cadmium uptake and mycorrhization by cacao clones in agroforestry and monoculture systems of Peruvian Amazon

The production system influences the cadmium (Cd) content and mycorrhization in cocoa plantations. The objective of this study was to determine the effects of different production systems on Cd uptake and the presence of mycorrhizas in cacao clones in field conditions, in the Peruvian Amazon. Twelve subplots of 108 m2 were selected in representative cocoa cultivation systems under agroforestry (AF) and monoculture (MON), with the cocoa clones ICS and CCN. Significant differences and data distribution were evaluated using ANOVA, principal component analysis, and Tukey's tests. Mycorrhizal colonization was higher in the AF_ICS system (71.11%) while the length of the extraradical mycelium was higher in the AF_CCN system (17.23%). The highest Cd content in soils was found under the AF_CCN and AF_ICS systems, both with 0.39 mg kg-1. The Cd content in cacao roots, leaves, and beans were higher in the MON_CCN system with 1.87, 2.06, and 1.12 mg kg-1 respectively. Cocoa monocultures (with both clones) generally showed lower levels of mycorrhizal colonization than agroforestry systems, which in turn (also for both clones) presented higher Cd content in beans, even exceeding the limit established by the world health authorities.

Dry matter intake and feed efficiency of heifers from 4 dairy breed types grazing organic grass and grass-birdsfoot trefoil mixed pastures

Insufficient dry matter intake (DMI) of pasture by dairy cattle is a major factor limiting growth and milk production; however, it has been hypothesized that some dairy breeds may be more efficient grazers than others. This study was conducted to determine whether dairy breed types differ in DMI and feed efficiency when grazing either grass monoculture or grass-legume mixed pastures. The experiment compared 4 different dairy breed types (Jersey, Holstein, Holstein-Jersey crossbreds, and Montbéliarde-Swedish Red-Holstein 3-breed crossbreds) and 2 levels of pasture type [grass monoculture (MONO) and grass-birdsfoot trefoil (BFT) mixture (MX)] for a total of 8 treatments. Pastures were rotationally stocked with groups of 4 prepubertal heifers for 105 d for 3 yr, and DMI was determined from herbage disappearance. Feed conversion efficiency (FCE) and residual feed intake (RFI) were then derived from DMI, and heifer body weights (BW) and normalized to animal units (AU) as 40% metabolic mature BW of the corresponding dairy breed type to account for inherent differences in size and growth rates. We observed differences in DMI and feed efficiency among breed types and between pasture types. On average, Holsteins had the greatest overall DMI (4.4 kg/AU), followed by intermediate DMI by the crossbreds (4.0 kg/AU), and Jerseys had the least DMI (3.6 kg/AU). Heifers grazing MX pastures had on average 22% greater DMI than those grazing MONO, but heifers on grass monocultures were more efficient in converting DMI to BW gain (i.e., RFI/AU of 0.27 and -0.27, respectively; more negative RFI numbers indicate less DMI to achieve the expected gains). Overall, Jerseys had the most favorable feed efficiency; however, ranking of Holsteins and crossbreds depended upon the feed efficiency metric. This study is one of the first to compare the interaction of dairy breed and pasture quality on grazing efficiency. However, the lack of a breed type × pasture type interaction for DMI, FCE, or RFI indicated that none of these dairy breed types were better adapted than another breed type to pastures with contrasting levels of nutritive value.

Morpho-physiological and anatomical characteristics of Urochloa brizantha cv. Marandu in silvopastoral and monoculture systems

To gain insights into the forage morphological and anatomical characteristics in a silvopastoral system (SPS) with Bolsa de Pastor (Zeyheria tuberculosa) and palisadegrass ‘Marandu’ (Urochloa brizantha) monoculture (MONO). The SPS was established through natural regeneration of the tree species. Treatments were a SPS and MONO distributed in a completely randomized design with six replicates and repeated measures were the harvest periods. Response variables were morpho-physiological and anatomical characteristicss: green: dead material ratio, leaf blade: stem+sheath ratio, leaf area index, chlorophyll and carotenoid concentrations, proportions of non-lignified and achlorophyllous areas, lignified areas in stems, proportions of non-lignified and achlorophyllous areas, lignified and chlorophyllous areas in leaves, as well as cell length in longitudinal section of stem. Morpho-physiological patterns were altered (p < 0.05) under natural shading conditions due to higher photosynthetic efficiency in the SPS. There was no effect (p > 0.05) of the systems on anatomical patterns, proportions of non-lignified and achlorophyllous, lignified and chlorophyllous tissues, these proportions were influenced only by the periods of the year, both for stems and leaves. Cells of the internodes of the grasses of the studied systems had the same length. The SPS alters morpho-physiological characteristics of palisadegrass and increases the concentration of chlorophyll a and b.

An alternative in vitro model considering cell-cell interactions in fiber-induced pulmonary fibrosis

Particularly since the wide-ranging health effects of asbestos exposure became known, great emphasis has been placed on detailed toxicity testing of known but also newly developed fiber materials. Exposure to respirable pollutants like fibers can lead to tissue injury causing lung diseases such as pulmonary fibrosis or cancer. In order to detect the toxic potential of such aerosols at an early stage, the development of suitable test systems is essential. In this study, we illustrate the development of an advanced in vitro cell model closely resembling the physiological structure of the alveoli, and we highlight its advantages over simpler models to predict pro-fibrotic changes. For this reason, we analyzed the cytotoxic effects of fiber-like multi-walled carbon nanotubes after 24 and 48 h exposure, and we investigated inflammatory, genotoxic and pro-fibrotic changes occurring in the developed triple culture consisting of lung epithelial cells, macrophages and fibroblasts compared to a co-culture of epithelial cells and fibroblasts or a mono culture of epithelial cells. In summary, the triple culture system is more precisely able to detect a pro-fibrotic phenotype including epithelial-mesenchymal transition as well as secondary genotoxicity, even if exhibiting lower cytotoxicity in contrast to the less advanced systems. These effects might be traced back to the complex interplay between the different cell types, all of which play an important role in the inflammatory response, which precedes wound healing, or even fibrosis or cancer development.

The influence of agricultural practices on yield and weed infestation of winter triticale

This study aimed to evaluate grain yield and weed infestation of winter triticale grown in various cropping and tillage systems. The first order factor studied was the cropping systems (CS): (1) crop rotation A (CR-A): peas – winter barley – winter triticale; (2) crop rotation B (CR-B): lupin – winter wheat – winter triticale; and (3) winter triticale monoculture (MON). The second order factor included tillage systems (TS): (a) conventional (CT); (b) reduced (RT); and (c) no-tillage (NT). A significantly higher triticale grain yield was recorded in CR-A and CR-B than in MON, and also in CT than in RT and NT, due to higher spike number per 1 m2, grain weight per spike, and 1000 grain weight. The weed community formed in triticale crop was mainly represented by short-lived species. A higher weed number per 1 m2 was determined in CR-A and MON than in CR-B as well as in RT than in CT and NT. In turn, weeds produced a higher air-dry weight of weeds in MON than in CR-Aand CR-B, and also in RT than in CT and NT. The tillage system affected the weed contribution in particular levels of winter triticale crop, with the lower-level and middle-level species prevailing in CT and RT, and the middle-level and upper-level ones in NT.

Use of recirculation and settling chamber in synbiotic multi‐trophic culture of Crassostrea sp. with Litopenaeus vannamei

The objective of this work was to evaluate the use of recirculation and settling chamber in synbiotic multi-trophic culture of Crassostrea sp. with Litopenaeus vannamei. Four treatments were tested: MONO (shrimp monoculture); integrated multi-trophic aquaculture (IMTA) (shrimp and oysters in the same tank); IMTA-R (shrimp and oysters in adjacent tanks with recirculation) and IMTA-RS (shrimp and oysters in adjacent tanks with recirculation using settling chamber). Shrimp post-larvae (pL10) and oyster juveniles (3.12 cm) were stocked at a density of 3000 pL m−3 and 200 oysters m−2, respectively, for 42 days. The IMTA treatments showed lower values of settleable solids, when compared to monoculture. However, the excessive removal in the IMTA-RS increased the levels of TAN (1.15 mg L−1) and nitrite-N (3.47 mg L−1). The weight and yield of shrimp (1.59 g and 4.63 kg m−3) and the weight of oysters (18.05 g) was significantly higher in the IMTA. Regarding the planktonic community analysis, significant difference was observed on abundance in relation to time and among treatments, where the initial samples and IMTA treatments, with lower values, differed from the 21st and 42nd days and MONO respectively. The results indicate the benefits of the integrated multi-trophic culture application with the two species in the same productive unit for better water quality and greater shrimp growth.

Soil Microbial Diversity and Community Composition in Rice-Fish Co-Culture and Rice Monoculture Farming System.

Simple SummaryThe integration of fish in rice fields can influence the diversity and structural composition of soil microbial communities. Therefore, soil microorganisms between rice–fish co-culture (RF) and rice monoculture (MC) were compared. The key findings revealed that Actinobacteria, Chloroflexi, Proteobacteria, Acidobacteria, and Planctomycetes were the most dominant taxa across both paddy fields. The most abundant genus in MC belonged to Anaeromyxobacter, whereas that in RF was Bacillus. Nitrogen fixation, aromatic compound degradation, and hydrocarbon degradation were more abundant in RF. Phosphatase, β-glucosidase, cellulase, and urease enzymes were detected in both paddy fields. However, a 2-year conversion from organic rice to rice–fish co-culture may not be long enough to significantly alter alpha diversity indices.Soil microorganisms play an important role in determining nutrient cycling. The integration of fish into rice fields can influence the diversity and structural composition of soil microbial communities. However, regarding the rice–fish co-culture (RF) farming system in Thailand, the study of the diversity and composition of soil microbes is still limited. Here, we aim to compare the microbial diversity, community composition, and functional structure of the bacterial communities between RF and rice monoculture (MC) farming systems and identify the environmental factors shaping bacterial community composition. Bacterial taxonomy was observed using 16s rRNA gene amplicon sequencing, and the functional structures of the bacterial communities were predicted based on their taxonomy and sequences. The results showed that soil organic carbon, total nitrogen (TN), organic matter, available phosphorous, and clay content were significantly higher in RF than in MC. The most dominant taxa across both paddy rice fields belonged to Actinobacteria, Chloroflexi, Proteobacteria, Acidobacteria, and Planctomycetes. The taxa Nitrosporae, Rokubacteria, GAL15, and Elusimicrobia were significantly different between both rice fields. At the genus level, Bacillus, Anaeromyxobacter, and HSB OF53-F07 were the predominant genera in both rice fields. The most abundant genus in MC was Anaeromyxobacter, whereas RF belonged to Bacillus. The community composition in MC was positively correlated with magnesium and sand content, while in RF was positively correlated with pH, TN, and clay content. Nitrogen fixation, aromatic compound degradation, and hydrocarbon degradation were more abundant in RF, while cellulolysis, nitrification, ureolysis, and phototrophy functional groups were more abundant in MC. The enzymes involved in paddy soil ecosystems included phosphatase, β-glucosidase, cellulase, and urease. These results provide novel insights into integrated fish in the paddy field as an efficient agricultural development strategy for enhancing soil microorganisms that increase soil fertility.

Weed flora in crop rotation and winter wheat monoculture

Aim of study: The goal of the study described in this manuscript was to evaluate qualitative and quantitative changes in weed flora infesting winter wheat stands grown in crop rotation and wheat monoculture. Area of study: South-eastern Poland, Europe (2018-2020). Material and methods: The experiment was established in the system of randomized blocks (25 m x 6 m) in three replications. Winter wheat was sown in (1) crop rotation (CR): potato – winter wheat – peas – winter barley; and (2) in monoculture (MON). Weed infestation was evaluated in two terms: (1) at the tillering stage and (2) at the waxy maturity stage of winter wheat. Main results: The number and air-dry weight of weeds evaluated in both terms were higher in MON than in CR. Before wheat harvest, its plots in MON were massively infested by Apera spica-venti and significantly populated by Avena fatua and Anthemis arvensis. In this evaluation term, the weeds of the upper and middle levels accounted for 88.4% of the whole weed community in CR and for 97.7% in MON. In both terms of evaluation, greater biodiversity of the weed community was observed in CR than in MON. Research highlights: Indicators used to assess the weed flora in crop rotation and monoculture, i.e. weed species composition, number and air-dry weight of weeds, weed distribution in wheat crop levels, and Shannon-Wiener's diversity index.

Crabgrass as an equine pasture forage: impact of establishment method on yield, nutrient composition, and horse preference

Warm-season grasses (WSG) incorporated into traditional cool-season rotational grazing systems to increase summer yields are typically established in monoculture in separate pasture areas. Few studies have evaluated alternative interseeded establishment of WSG, despite potential benefits for improving biodiversity and land-use efficiency. The objective of this study was to determine the impact of establishment method (monoculture vs. interseeded) on crabgrass pasture forage yield, nutritive value, and preference under equine grazing. Three adult standardbred mares grazed two main plots on two consecutive days (8 hr/d) for three grazing events in 2019: Jul 28/29 (GRAZE 1), Aug 20/30 (GRAZE 2), Oct 1/2 (GRAZE 3). Each main plot contained four replicates of three treatments: mixed cool-season grass (CSG); Quick-N-Big crabgrass (CRB) [Digitaria sanguinalis (L.) Scop.] interseeded into existing cool-season grass (INT), and CRB established as a monoculture (MON). The cool-season grass mix included Inavale orchardgrass [Dactylis glomerata (L.)], Tower tall fescue [Lolium arundinaceum (Schreb.) Darbysh.], and Argyle Kentucky bluegrass [Poa pratensis (L.)]. Herbage mass (HM) and sward height (SH) were measured prior to each grazing event and samples were collected (0800–1000 h) for chemical composition analysis. Observed grazing time (GT) in each sub-plot as determined by 5-min scan sampling was utilized as marker of horse preference. Forage HM was greater in MON (8043 ± 1220 kg/ha) than CSG (5001 ± 1308 kg/ha; P = 0.003), with a trend for greater total HM in MON vs. INT (6582 ± 1220 kg/ha: P = 0.06), but HM did not differ between INT and CSG. The SH was also greatest for MON (28 ± 1.11; INT: 23.6 ± 1.11; CSG: 19.7 ± 1.37 cm; P < 0.003). Forage nutrients (digestible energy and crude protein) were largely similar across treatments and met requirements of horses at maintenance. Horse GT was lower in MON (22.6 ± 3.77 min/sub-plot) than in INT (31.9 ± 3.79 min/sub-plot; P = 0.003) and there was a trend for lower GT in MON vs. CSG (29.9 ± 4.17 min/sub-plot: P = 0.07). These results indicate interseeding CRB would not effectively increase yields of traditional cool-season grass equine rotational grazing systems and would not supply similar levels of summer forage provided by monoculture establishment. Results of this study also suggest horses may prefer cool-season grass pasture forage over warm-season crabgrass.

Illustrating the past, present and future perspective of Human Embryo Culture Media

Culture media has an important role in invitro embryo development and in determining the success rate of assisted reproduction technologies. Extensive research during the last few decades have brought about major advancements in the IVF culture media. Studies on the composition of the mammlian oviductal fluids and the uterine fluids have improved our understanding on the evolving metabolic needs of the preimplantation embryo. This has led to the gradual development of human IVF media, from simple salt solutions to highly complex defined media. Regarding ideal composition of IVF culture media two different philosophies have come up: “back-to-nature” or sequential culture principle and “let-the-embryo-choose” or one-step culture principle. Sequential culture closely mimics the physiological conditions of female reproductive tract, while the mono culture system employs simultaneous use of all components in an optimal concentration. Besides role in viability maintenance, culture media can also take up a new role as a therapeutic agent in future. The improvised media apart from maintaining the viability may work on improving the quality of gametes/embryos obtained from poor prognosis patients. This review would discuss the progressive evolution of embryo culture media based on studies on pre-implantation embryo physiology and lastly will hypothesize the future of this technology.

Nitrous oxide emissions in silvopastoral systems: Key driving variables and seasonality

Silvopastoral systems are suggested to be important strategies for mitigating greenhouse gas emissions. However, little information is available on the effects of these systems on soil nitrous oxide (N2O) production. Expanding the knowledge of N2O emissions and the responses of key variables that drive N2O production are essential for understanding nitrogen loss. To quantify these factors in the silvopastoral system (Eucalyptus grandis × Megathyrsus maximus) and the monoculture (Megathyrsus maximus Guinea Massai grass), we conducted a 4-year field assessment. The experimental design was a completely randomized block with two factors: (1) monoculture (MONO) and silvopastoral systems with tree rows of 12 m (SP1) and 6 m (SP2), and (2) two seasons (rainy and dry), with 5 repetitions. Emissions were quantified using the closed static chamber methodology and gas chromatography analysis. In the wet summer, the silvopasture system differed from MONO, while in the dry winter, only the SP1 group differed from the monoculture; N2O emissions were higher during the rainy season. The MONO treatment revealed larger N2O fluxes in the first year of evaluation, whereas the silvopasture systems peaked in a later year. A significant positive Pearson correlation was found between N2O fluxes and soil moisture (r=0.89; P < 0.001) and soil temperature (r=0.76; P< 0.01). Our study showed that the effect of the silvopastoral system was season-dependent. N2O emissions increased over the years in silvopastoral systems, as opposed to the monoculture, and were driven by soil moisture and temperature.

167 Impacts on Biodiversity, Environment and Society of Beef Production in the Mexican Tropics: A Life Cycle Assessment Approach

Abstract Beef production exerts strong environmental pressures and can also generate negative social effects. In this study, the impacts on biodiversity, environment and society of beef production in the Mexican tropics, were evaluated through the Life Cycle Assessment (LCA) approach. The functional unit of the study was 1 kg live weight of calf and focused on three productive systems: native silvopastoral (NSP), intensive silvopastoral (ISP) and monoculture (MC). This research was divided into four analysis steps. (1) social impacts; (2) damage to biodiversity; (3) methane emissions and 4) environmental LCA impacts. Using the Social-LCA, we evaluated 18 social indicators, grouped into five categories: human rights, working conditions, health and safety, socio-economic repercussions, and governance. The results showed similarities between the three livestock systems, which revealed a deficient social performance. For projecting the biodiversity damage of pasture land use from an LCA perspective, characterization factors (CFs) were estimated. CFs consist of dimensionless figures representing the potential for damage per unit area of pasture land (potential species loss per m2). The CFs were calculated for three levels of pasture land use intensity (minimal/NSP, light/ISP, intense/MC). Based on the characterization factors developed, the MC showed the least potential species loss. Enteric methane emissions from the production systems were determined using the IPCC Tier 2. The results revealed that the emissions values from enteric methane calculated with Tier 1 overestimated the emissions compared to Tier 2 methodology. LCA indicated a lower environmental impact of the MC on four of the seven categories analyzed, highlighting its lower contribution to climate change and reducing species loss. However, consumption of water and scarcity of fossil fuel resources increased. To achieve tropical sustainable livestock farming, further lines of research should be aimed at evaluating its economic impacts and propose management systems that guarantee better social and environmental performance.