Pasture Yield Research Articles

84 Pasture production in integrated warm- and cool-season grass equine rotational pasture systems

Incorporating warm-season grasses (WSG) into traditional cool-season (CSG) rotational pastures has been utilized to increase summer forage available for grazing cattle. The aim of this study was to evaluate the impact of this practice on yield and nutritive value of horse pastures. We hypothesized WSG incorporation would increase summer pasture yield, while being lower in non-structural carbohydrates (NSC). Two 1.5 ha rotational systems (6–0.25 ha sections/system) were utilized: a control system (CON) with all sections containing an established CSG mix (Kentucky bluegrass, orchardgrass, and tall fescue), and an integrated system (IRS) [3 CSG sections (CSG-IRS) and 3 Quick-N-Big crabgrass (CRB-IRS)]. Three horses per system grazed across 3 periods: EARLY (mid-May to mid-Jul), SLUMP (mid-Jul to mid-Sep), and LATE (mid-Sep to mid-Nov). Horses were confined to dry lots if sufficient pasture forage was not available. Before each rotation, herbage mass (HM) was measured and forage samples collected (0800–1000) with nutrients analyzed by wet chemistry. Grazing days were tracked to calculate carrying capacity (CC). Data were analyzed by ANOVA and means separated by Tukey's method in R. Over the full grazing season, IRS provided pasture access for 123 d, while CON supported grazing for 104 d (69% and 59% of total). Total HM per section did not differ during EARLY grazing when CRB was not available (CSG-IRS: 2537 ± 605; CSG-CON: 3783 ± 856 kg/ha), but CC was greater in CSG-IRS (220 ± 37 horse d/ha) than in CSG-CON (92 ± 26 horse d/ha; P = 0.03). In SLUMP grazing, both HM and CC were greater in CRB-IRS (HM: 4758 ± 698 kg/ha; CC: 196 ± 31 horse d/ha) than either CSG-IRS (HM: 1086 ± 698 kg/ha; CC: 32 ± 31 horse d/ha) or CON (HM: 970 ± 493 kg/ha; CC: 46 ± 22 horse d/ha; P < 0.02). While HM did not differ by section type in LATE grazing (1284 ± 158 kg/ha), CC was greater in CON (84 ± 9 horse d/ha) vs CRB-IRS (32 ± 13 horse d/ha; P = 0.03) and CSG-IRS (40 ± 13 horse d/ha; P = 0.06). During the SLUMP, water-soluble carbohydrates (WSC) were lower in CRB-IRS (4.46 ± 0.80%) than CSG-CON (7.92 ± 0.90%; P < 0.04), but not CSG-IRS (5.93 ± 1.04%); however, non-structural carbohydrates (NSC) did not differ (7.05 ± 0.62%). There were no differences in either WSC (6.46 ± 0.54%) or NSC (7.65 ± 0.54%) by section type in LATE grazing. These results demonstrated increased summer horse pasture yield through integrated grazing, but further research is needed to improve late-season production. Additionally, integrated grazing provided lower WSC to grazing horses, but NSC remained below 10% for all pasture sections.

47 Integrated warm- and cool-season grass rotational grazing management and the equine fecal microbiome

Warm-season grasses can be integrated into traditional cool-season grass equine rotational grazing systems to increase summer pasture yield. The objective of this study was to evaluate impacts of this management strategy on the fecal microbiome of grazing horses. Eight mares were randomly assigned to 2 integrated rotational systems (IRS) containing mixed cool-season grass and 1 of 2 warm-season grasses: bermudagrass or crabgrass. Fecal samples were collected after a 3-wk adaptation to each of the following forages: initial cool-season hay (HAY-SP); cool-season pasture in spring (CSG-SP), warm-season pasture in summer (WSG), and cool-season pasture in fall (CSG-FA); and after transition back to hay in the fall (HAY-FA). Analysis of 16S rRNA gene sequences was conducted in QIIME 2, and taxonomy was assigned with SILVA. Alpha diversity metrics were analyzed using a mixed effects model, and β diversity by PERMANOVA. Amplicon sequence variants (ASV) were clustered into bacterial co-abundance groups (BCG) using Sparse Cooccurrence Network Investigation for Compositional data. A random forest classifier was applied to determine if forage could be predicted by BCG composition. BCG specific to each forage were identified by LEfSe, with significance set at LDA > 2.0. Differences were not found between IRS, and combined data are presented (n = 8). Alpha and β diversity metrics differed across forages ( P < 0.05). In addition, random forest modeling was able to predict forage type (accuracy: 0.78 ± 0.15), indicating that shifts in microbiome structure and species composition occur as horses adapt to different forages within IRS. BCG including ASV assigned to Oscillospiraceae and Lachnospiraceae families and within Christenellaceae R-7 group and Eubacterium coprostanoligenes group genera were identified by LEfSe as markers for all forages. BCG specific to HAY-SP included ASV within Roseburia, Blautia , and Saccharofermentans , while Bacteriodales BS11 gut group was enriched in CSG-SP. BCG including ASV from Alloprevotella and Denitrobacterium detoxificans were enriched in CSG-FA, and Streptococcus and Lactobacillus equigenerosa in HAY-FA. BCG members characteristic of WSG included ASV within Bacillus, Akkermansia, and Clostridium butyricum – taxa associated with healthy gut function and investigated for probiotic use in humans and other animal species. These results suggest incorporation of WSG in IRS may be of benefit to grazing horses. However, given the complexity of microbial community dynamics and limitations of taxon-based functional inference, future research is necessary to evaluate potential physiological implications.

Respuesta del pasto Yacaré (Urochloa híbrido cv. CIAT BR02/1752) a la biofertilización con hongos micorrízicos arbusculares

With the aim to evaluate the biofertilization effectiveness with arbuscular mycorrhizal fungi in Yacare pasture ( Urochloa hybrid) cultivated in Lixiviated Ferrallitic Red soil, an experiment was carried out at Nina Bonita Genetic Cattle Enterprise. Four treatments were evaluated: three species of arbuscular mycorrhizal fungi (AMF), Glomus cubense , Funneliformis mosseae , and Rizhophagus irregularis , in addition to a control without inoculating, distributed in a Latin square design. Different species inoculation of AMF was carried out at sowing time. The indicators evaluated were the frequency and intensity of mycorrhizal colonization, AMF spore number in the rhizosphere, the NPK biomass concentrations, the dry mass yield of the pasture and its nutritive value, as well as the efficiency index and AMF strains influence in pasture nutrition. All the strains produced significant increases in the evaluated variables; nevertheless, when G. cubense was inoculated, increases in the efficiency index and in pasture nutrition were obtained. It is concluded that biofertilization with G. cubense can be an effective agronomic practice to improve the yield and nutritive value of the Yacare pasture cultivated in Lixiviated Ferrallitic Red soil.

National Mapping of New Zealand Pasture Productivity Using Temporal Sentinel-2 Data

A national map of pasture productivity, in terms of mass of dry matter yield per unit area and time, enables evaluation of regional and local land-use suitability. Difficulty in measuring this quantity at scale directed this research, which utilises four years of Sentinel-2 satellite imagery and collected pasture yield measurements to develop a model of pasture productivity. The model uses a Normalised Difference Vegetation Index (NDVI), with spatio-temporal segmentation and averaging, to estimate mean annual pasture productivity across all of New Zealand’s grasslands with a standard error of prediction of 2.2 t/ha/y. Regional aggregates of pasture yield demonstrate expected spatial variations. The pasture productivity map may be used to classify grasslands objectively into stratified levels of production on a national scale. Due to its ability to highlight areas of land use intensification suitability, the national map of pasture productivity is of value to landowners, land users, and environmental scientists.

How important is the description of soil unsaturated hydraulic conductivity values for simulating soil saturation level, drainage and pasture yield?

Accurate simulation of soil water dynamics is a key factor when using agricultural models for guiding management decisions. However, the determination of soil hydraulic properties, especially unsaturated hydraulic conductivity, is challenging and measured data are scarce. We investigated the use of APSIM (Agricultural Production Simulation Model) with SWIM3 as the water module, based on Richards equation and a bimodal pore system, to determine likely ranges of the hydraulic conductivity at field capacity (K-10; assumed at a matric potential of −10 kPa) for soils representing different drainage characteristics. Hydraulic conductivity measurements of soils with contrasting soil drainage characteristics and values for K-10 were extracted from New Zealand’s national soil database. The K-10 values were then varied in a sensitivity analysis from 0.02 to 5 mm d−1 for well-drained soils, from 0.02 to 1 mm d−1 for moderately well-drained soils, and from 0.008 to 0.25 mm d−1 for poorly drained soils. The value of K-10 had a large effect on the time it took for the soil to drain from saturation to field capacity. In contrast, the saturated hydraulic conductivity value had little effect.Simulations were then run over 20 years using two climatic conditions, either a general climate station for all seven different soils, or site-specific climate stations. Two values for K-10 were used, either the APSIM default value, or the soil-specific measured K-10. The monthly average soil saturation level simulated with the latter has a better correspondence with the morphology of the seven soils. Finally, the effect of K-10 on drainage and pasture yield was investigated. Total annual drainage was only slightly affected by the choice of K-10, but pasture yield varied substantially.

Compaction induced soil structural degradation affects productivity and environmental outcomes: A review and New Zealand case study

Agricultural intensification has enhanced productivity, but has also negatively affected soil structure and environmental outcomes. Agriculture is among New Zealand (NZ)'s largest industries. Like other countries, significant land use intensification over the last 20–30 years has occurred in NZ, resulting in undesirable side-effect of soil structural degradation (SSD) (e.g., soil compaction, aggregate fragmentation). Using NZ as a case study, we reviewed and, where possible, quantified the extent of SSD in NZ and its impacts and implications on production, contaminant losses via drainage and runoff, and N2O emissions. Knowledge gaps were identified that will help guide future research both in NZ and internationally. Our review revealed that SSD is common in many regions and under different land uses in NZ. At the national scale, 44% of sites monitored between 2014 and 2017 were below the national target for macroporosity (pore diameter > 30 μm). The occurrence of SSD was greater under more intensive land uses such as dairying and continuous cropping. Soil structural degradation from compaction is typically associated with reduced pasture and crop production. In NZ, pasture production was estimated to decrease by an average of 2.5% for every 1.0% (0.01 cm3 cm−3) decrease in macroporosity (0–10 cm soil). Compaction from livestock treading and wheel traffic has been shown to increase N2O emissions by 51–814% and 19–1300%, respectively, with no significant evidence that this increase is related to N loading. Effects of compaction on contaminant losses via runoff and drainage, and in particular via preferential flow, are less well researched and findings were less consistent and dependent on many factors including the degree of compaction. Important knowledge gaps include a lack of quantitative relationships between degree of SSD and soil hydraulic properties and processes (e.g., water movement and contaminant losses), and poor knowledge of critical thresholds or optimum ranges of soil physical indicators in relation to critical ecosystem services (e.g., pasture yield, gas and water regulation in soils). We also found few estimates of SSD-induced costs related to production and environmental outcomes (e.g., contaminant losses and N2O emissions) at either farm system, regional or national scales. More data are needed to better determine the true costs and implications for farm production and environmental effects associated with SSD.

Seventy years of data from the world\u2019s longest grazed and irrigated pasture trials

Pastures are the most widespread land use, globally. The Winchmore trials were established in 1948–1949 in Canterbury, New Zealand and examined either different rates of phosphorus (P) fertiliser on the same irrigation schedule (Fertiliser trial), or different irrigation scheduling at the same rate of P application (Irrigation trial). About 96,000 records of soil chemistry and physical data and pasture yield and botanical composition are available along with nearly 7000 soil samples. These data have been used in 475 publications that have explored topics as diverse as: improvements in sheep, dairy and deer production; the efficacy and scheduling of irrigation; improvements in pasture and crop production; agronomic and environmental soil and water research; and entomology. In addition to above topics, these data are invaluable for calibrating models to predict long-term issues like the accumulation of soil carbon or contaminants like cadmium and informing policy on climate change and agricultural practices. The data and soil samples are available for use and may yet yield discoveries, unforeseen 70 years ago.

Effects of cutting frequency and levels of nitrogen fertilizer on herbage yield of a guinea grass (Panicum maximum) pasture.

The effects of fertilizer-N application and cutting frequency on the herbage yield of Panicum maximum pasture were investigated in 2001 through 2004 in a sandy loam soil at Nsukka. The experiment was a 4r 4 factorial arrangement laid out in a randomized complete block design with three replications. Treatments comprised four levels of Nitrogen of 0, 150, 300, and 450 kg N ha' and four harvesting frequencies of 3-6-19- and 12-weekly intervals, resulting in süteen treatment combinations per block, Grass dry matter yield increased significantly (P &lt; 0.05) from 7.799 to 10,993 kg ha' and from 5,715 to 14,220 kg ha' when the interval between cuts extended from 3 to 12 weeks at the first and fourth harvest years, respectively. Pasture plots cut at 3- or 6 weeks intervals exhibited much greater weed proportion than those cut at 9-, or 12-week interval. The total annual herbage dry matter yield increased significantly (P &lt; 0.05) from 8.564 to 11,312 kg ha and from 6,814 to 10,268 in 2001 and 2004, respectively, when fertilizer N was increased from 0 to 450 kg N ha. A combination of 12-weekly interval of cut with 300 kg N ha gave a significantly higher forage grass herbage dry matter yield compared with the values got from 3- or 6-weekly interval combined with any N rate. Fertilizing at 300-450 kg N ha when combined with cutting at 9 to 12-weekly interval bet ween citts was more effective in suppressing growth and proportion of weeds.&#x0D; &#x0D;

Do moisture conservation practices influence stability of soil organic carbon and structure?

As soil erosion is a major threat for global food security, soil and water conservation (SWC) structures are essential in degraded lands of the tropics facing water scarcity. However, some fundamental questions regarding the impact of SWC measures on soil aggregate stability, organic carbon (SOC) pools within bulk soils and aggregates, and biological activities remain unexplored. A 11-year study was conducted, involving a combination of tree (Emblica officinalis) + grass (Cenchrus ciliaris) + legume (Stylosanthes seabrana), comparing in-situ soil water storage measures, staggered contour trenches (SWC1), continuous contour trenches (SWC2), stone mulch (SWC3), and vegetative barriers (SWC4), to a control (SWC0). We calculated three novel indices: biological activity index (BAI), oxidative stability (OXS), and normalized soil stability index (NSSI). SWC1 and SWC2 reduced soil erosion by ~63% and 51% compared to SWC0. Labile C concentration improved by ~47, 31, and 15% for SWC1, SWC2, and SWC4 compared to SWC0. SWC1 and SWC2 had 50 and 33% greater recalcitrant C than SWC0, respectively, in the top layer. Considerably higher amount of aggregate associated C was observed with SWC1 and SWC2 than with SWC0. NSSI values of SWC1 and SWC2 were ~1.92- and 1.87-fold higher than that of SWC0 in the upper layer. BAI was improved by 1.34–2.65 times under SWC conditions compared to the control. For macroaggregates, OXS of C for SWC1 and SWC2 were ~12% higher than that for SWC0 at the surface. Overall, fruit and pasture yield under SWC1 were ~51 and 82% higher than SWC0, respectively. System water productivity was ~61% higher for SWC1 compared with SWC0. Therefore, staggered contour trenching or continuous contour trenching could be recommended for improving soil structural stability and SOC storage and for reducing soil erosion in degraded lands of semi-arid, dry, tropical regions.

Sustainability of beef production from brigalow lands after cultivation and mining. 2. Acland Grazing Trial pasture and cattle performance

Context Agricultural land used for open-cut coal mining in Queensland is required by law to be returned to a safe, stable and self-sustaining state for agriculture. Aims The aim of this research was to identify whether rehabilitated pastures on post-mine soil at a site near Acland could viably support cattle production. Methods Five years of field data from Botanal pasture assessments, pasture quality, cattle liveweights and faecal observations, plus supplementary cattle liver data, were used to compare pasture and cattle performance from mined and unmined previously cultivated brigalow land. Subtropical pasture species were sown in 2007 (Rehab1, 22 ha), 2010 (Rehab 2, 32 ha) and 2012 (Rehab3, 22 ha) in three rehabilitated paddocks and in 2012 in an unmined (Control, 21 ha) paddock. The paddocks were grazed for 117–190 days of each year by Angus cattle. Key results Mean total standing dry matter in grazed pasture over the five trial years was consistently higher in Rehab 2 (5656 kg/ha) than in the other paddocks. Rehab 1 (3965 kg/ha) and Rehab 3 (3609 kg/ha) performed at an intermediate level and the Control paddock produced less pasture (2871 kg/ha). Grass leaf crude protein was higher in Rehab 2 than in the other paddocks and declined significantly (P &lt; 0.001) across all paddocks as pasture aged. Pasture species remained perennial, palatable and productive in all paddocks; however, pasture yield, quality and composition trends over time suggested that pasture rundown occurred across all paddocks. The mean liveweight gain (LWG) per head when grazing the trial paddocks (trial LWG) was higher (P &lt; 0.05) in the Rehab 2 cohort than the other paddock cohorts in Years 3 and 5, and trial LWG in the Control cohort was not significantly (P &gt; 0.05) different from one or more of the rehabilitated paddock cohorts each year. Cattle production per hectare during the trial grazing periods was also consistently highest in Rehab 2 (5-year mean trial LWG 131 kg/ha) compared with the other paddocks (67–80 kg/ha). Conclusion The rehabilitated pastures in use by the mine were considered at least as productive as the surrounding unmined brigalow landscape. Implications The Acland rehabilitation process was considered successful in establishing pastures that were able to viably support cattle production.

Critical phosphorus values from the Better Fertiliser Decisions for Pastures project: early insights from validation trials

Phosphatic fertilisers have made grazing in the south-west of Western Australia (WA) viable. However, there is evidence that a large proportion of pasture paddocks exceed soil test critical values at which 95% of maximum yield is achieved as identified in the national Better Fertiliser Decisions for Pasture (BFDP) project. Of 22 000 soil samples collected between 2009 and 2020, 56% exceeded the critical value for phosphorus (P), although there were constraints to potassium (K) and sulfur (S) and from soil acidity. Soils with available P exceeding the critical value are expected to lead to excessive losses of P to waterways, resulting in eutrophication. A trial program was established to validate the critical P values from BFDP so that concerns can be addressed about the relevance of these critical P values to WA conditions and to contemporary pasture varieties. Measured relative yields for 19 trials in the first year were mostly within 10% of that predicted from BFDP for soils with a P buffering index (PBI) &gt;10. Soils with PBI &lt;10 had measured relative yields up to 25% greater than predicted by BFDP, suggesting response calibrations for low PBI soils may require adjustment in the BFDP dataset. Some pasture yield gaps occurred when soil pH and P were low. Application of nitrogen (N), K and S almost doubled the yield when P was limiting or sufficient. Agronomic advice and practice should seek to optimise these multiple inputs, thereby optimising P use rather than applying P to levels above the critical value.

Species selection tool: Soil‐specific forage species selection for New York State

AbstractSelection of forage species that are best suited to a particular soil type and forage use provide the most efficient land use. This program was developed to provide recommendations for perennial forage species in New York State, based on soil type and intended forage use through a web interface (http://www.forages.org). Forage species uses include both pasture and stored feed for different livestock classes as well as soil conservation uses. A database was developed that contains potential yields for more than 30 species and more than 40 species mixtures on each of 612 agricultural soil types in New York State. The database has potential forage yields based on native soil drainage as well as yields for optimal artificial drainage. Potential yields are modified by the program based on soil pH and the optimal pH range for each forage species. Species are recommended based on potential yield, intended forage use, and soil type. The program also provides pasture yield distributions, a summary of species traits, and potential corn grain and silage yields for a selected soil type. Computer‐based species recommendations agree with current published recommendations. The program has been used successfully by the National Resources Conservation Service and New York extension personnel for more than 20 years. Although the soil type/species yield relationships will not apply directly to other regions of the world, the method utilized to develop the database could be used to create similar species selection programs for other regions.

Sustainability of beef production from brigalow lands after cultivation and mining. 1. Sown pasture growth and carrying capacity

Context New Acland coal mine in south-eastern Queensland is seeking to rehabilitate mined land to pastures that are safe, stable and sustainable for beef production. Little is known of the productivity and sustainability of grazing previously mined land in the Darling Downs study region. Additionally, information is required to specify management guidelines for sustainable grazing of regional land types retired from cultivation. Aims Identify pasture growth characteristics, rainfall use efficiencies and long-term carrying capacities of subtropical sown pastures established on lands rehabilitated after open-cut coal mining in comparison to sown pastures established on un-mined but previously cultivated lands. Methods Pasture growth and quality (% nitrogen) were observed using the Swiftsynd methodology in ungrazed exclosures with three sites on rehabilitated lands of the Acland Grazing Trial over a 5-year period (2014–2018), and 13 sites on unmined lands over periods of 2–5 years providing data for modelling pasture growth. Key results Peak pasture yield (TSDM for autumn harvests) averaged for 2017 and 2018 was greater (P &lt; 0.1) on rehabilitated sites than unmined Poplar Box land type sites (5957 and 2233 kg/ha respectively) but similar to Brigalow Uplands and Mountain Coolibah land type sites (3946 and 3413 kg/ha respectively). Pasture rundown was evident, with pasture N uptake decreasing over 5 years at some sites. Soil mineral N supply (potentially mineralisable N and mineral N) in spring was a useful indicator of N uptake over the following growing season. Simulations using the GRASP pasture growth model for the grazing trial period predicted rainfall use efficiencies of 12.0, 7.0, 9.1 and 4.8 kg/ha.mm rainfall for rehabilitated sites and unmined sites on Brigalow Uplands, Mountain Coolibah and Poplar Box land types respectively. Long-term carrying capacities based on estimates of long-term median pasture growth and 30% utilisation were 4.39, 3.58 and 5.92 ha/adult equivalent respectively for the unmined land types, and 2.45 ha/adult equivalent for the rehabilitated lands. Conclusions Rehabilitated land can be as productive as unmined but previously cultivated land. Implications Grazing management plans for sustainable management of mined and unmined lands can be developed using data from the present study. The plans will assist with the transition of rehabilitated lands to commercial agriculture.

Determinants of the economic viability of mallee eucalypts as a short rotation coppice crop integrated into farming systems of Western Australia

AbstractMallee eucalypts are being developed as a short rotation coppice crop for integration into agricultural systems in the south‐west of Western Australia. These have potential for biomass production for bioenergy, eucalyptus oil and generating carbon credits and to help control the extensive occurrence of dryland salinity. Some 12,000 ha of mallee planting has been undertaken since 1994, mostly in the form of wide‐spaced, narrow belts within the annual agricultural system. Production and market data were used to estimate levelized costs (LC) of mallee biomass production under different harvest regimes across 11 sites from 2006 to 2012. We found LC ranged from AUD40 to AUD257 fresh Mg−1. LC was most strongly determined by mallee production, followed by the crop/pasture rotation decisions of the landholder. Mallee harvest regime had minor impact on LC. Crop and pasture yield loss due to competition from the mallee belts accounted for 38% of costs, harvesting biomass was 32%, opportunity cost of the land occupied by the mallee belts was 16% while establishment and maintenance costs accounted for 14% of the costs. When income from carbon sequestered in mallee root biomass was included, the LC dropped by an average of 11% at the current Australian price of AUD15 Mg−1 CO2 equivalent (CO2e). The income from carbon sequestered in root biomass alone is unlikely to make mallee agroforestry economically viable. Hence, income from harvested biomass in the form of feedstocks for industry or carbon credits is necessary to make mallee agroforestry commercially attractive. LC for unharvested mallee belts ranged from AUD33 to AUD237 Mg−1. Where above‐ and below‐ground biomass is converted to CO2e at AUD15 Mg−1, the LC drops to AUD11–AUD64, with three of 11 sites likely to be profitable. These three sites were characterized by high biomass production with low agricultural gross margins.

Estimating Plant Pasture Biomass and Quality from UAV Imaging across Queensland’s Rangelands

The aim of this research was to test recent developments in the use of Remotely Piloted Aircraft Systems or Unmanned Aerial Vehicles (UAV)/drones to map both pasture quantity as biomass yield and pasture quality as the proportions of key pasture nutrients, across a selected range of field sites throughout the rangelands of Queensland. Improved pasture management begins with an understanding of the state of the resource base, UAV based methods can potentially achieve this at improved spatial and temporal scales. This study developed machine learning based predictive models of both pasture measures. UAV-based structure from motion photogrammetry provided a measure of yield from overlapping high resolution visible colour imagery. Pasture nutrient composition was estimated from the spectral signatures of visible near infrared hyperspectral UAV sensing. An automated pasture height surface modelling technique was developed, tested and used along with field site measurements to predict further estimates across each field site. Both prior knowledge and automated predictive modelling techniques were employed to predict yield and nutrition. Pasture height surface modelling was assessed against field measurements using a rising plate meter, results reported correlation coefficients (R2) ranging from 0.2 to 0.4 for both woodland and grassland field sites. Accuracy of the predictive modelling was determined from further field measurements of yield and on average indicated an error of 0.8 t ha−1 in grasslands and 1.3 t ha−1 in mixed woodlands across both modelling approaches. Correlation analyses between measures of pasture quality, acid detergent fibre and crude protein (ADF, CP), and spectral reflectance data indicated the visible red (651 nm) and red-edge (759 nm) regions were highly correlated (ADF R2 = 0.9 and CP R2 = 0.5 mean values). These findings agreed with previous studies linking specific absorption features with grass chemical composition. These results conclude that the practical application of such techniques, to efficiently and accurately map pasture yield and quality, is possible at the field site scale; however, further research is needed, in particular further field sampling of both yield and nutrient elements across such a diverse landscape, with the potential to scale up to a satellite platform for broader scale monitoring.

Persistence of perennial ryegrass, tall fescue and cocksfoot following sequential annual sowings: pasture yield, composition and density in three establishment years under cattle grazing in Waikato

Persistence is an important component of perennial pasture-grass productivity. Defining the traits that affect persistence is essential for improving pasture longevity through plant breeding and for identifying criteria that should be included in cultivar ranking indices. Compared with a conventional longitudinal study (a single study monitored over time), repeated annual sowings allow the effects on persistence of sowing year and the ensuing interactions between environment and age of pasture to be identified. An experiment commenced in 2016 in Waikato, in which eight cultivars of perennial ryegrass representing different ploidy, flowering date, and cultivar age, and one each of tall fescue and cocksfoot were sown each autumn in a randomised complete block design with four replicates in autumn 2016, spring 2017 and autumn 2018. This paper reports interim data on pasture yield, composition and density in the autumn following each sowing, and for the 2018 sowing only, in the 6 months after sowing. For the three successive autumn measurements there were significant effects due to cultivar, year of sowing and their interactions for all pasture variables. These differences in establishment may have consequences for the future resilience of these pastures under natural biotic and abiotic stressors.

Effects of fertilizer type and harvesting age on species composition, yield and chemical composition of natural pasture in the highlands of Ethiopia

Abstract. Yalew S, Asmare B, Mekuriaw Y. 2020. Effects of fertilizer type and harvesting age on species composition, yield, and chemical composition of natural pasture in the highlands of Ethiopia. Biodiversitas 21: 4999-5007. The experiment was conducted to evaluate the effects of fertilizer type and harvesting age on species composition, yield, and chemical composition of natural pasture in the highlands of Ethiopia. The experiment was laid out in randomized complete block design with factorial arrangement of two factors (fertilizer and harvesting age) with five replications. The data collected from the current study were forage species composition, dry matter yield, and chemical composition of natural pasture at different ages of harvesting. Forage species composition was determined by taking representative samples and identifying species from each sampling site. The samples of natural pasture were harvested at 90 and 120 days of age, weighed, dried, and then ground after that subsamples were taken for analyses of dry matter (DM), crude protein (CP), ash, acid detergent fiber (ADF), neutral detergent fiber (NDF) and acid detergent lignin (ADL). All the collected data were subjected to GLM ANOVA procedures of SAS version 9.0. The result indicated that all species composition and dry matter yield were significantly affected (P&lt;0.001) by fertilizer type and harvesting ages. Higher forbs (0.66%) were found in control plot at 90 days of harvesting age. Natural pasture harvested at 120 days of harvesting and urea fertilizer application results the highest dry matter yield (DMY) (8.26 t/ha) while the lowest level (3.20 t/ha) from unfertilized plot at 90 and 120 days of harvesting. The relative proportion of legumes in the natural pasture attained its climax stage at 90 days while grass attained at 120 days of harvesting. The highest mean DMY (6.24 tone/ha) was obtained at 120 days of harvesting and the lowest (4.71 ton/ha) at 90 days of harvesting. Among the chemical composition parameters, DM, ash and CP were significantly affected (P&lt;0.001) by both fertilizer type and harvesting age. The content of CP and ash were increased with manure fertilizer at early harvest age and were decreased with delayed harvest age. The application of fertilizer type did not significantly affect (P&gt;0.05) NDF content of the natural pasture rather affected by stage of harvesting (P&lt;0.001). Regardless of DM yield, better quality pasture was recorded for early (90 days) harvesting age and use of compost recommended for future natural pasture improvements as use of chemical fertilizer is relatively expensive for the majority of smallholder farmers in the highlands.

Yield and Composition of Natural Pastures from the Plains and Semi-mountainous Regions of Central Northern Bulgaria

One of the main problems in modern agricultural production is the inefficient use and management of natural resources. The aim of the present study is to analyze the productivity and assess the species composition of natural pastures (Np) used for grazing by sheep in farms in the region of Central Northern Bulgaria. The observations were carried out in the period mid-April - mid-June 2018-2019, at intervals of 14 days on eight natural grasslands located in the region of Central Northern Bulgaria. They are selected to cover the most typical and used natural pastures in the plains and semi-mountains of the region. The comparative assessment of the 8 plant populations of pasture type, subject of the present study, under the ecological conditions of Central Northern Bulgaria showed the highest yield of dry mass observed in the natural meadows in the plains - Np 4 (780.67 kg ha-1) , followed by Np 6 (760.09 kg ha-1) and Np 8 (740.24 kg ha-1), an average of 760.33 kg ha-1. The grasslands from semi-mountains of the region (Np 1, 2 and 3), show a different reaction to the growing environment, but all of them are characterized by significantly lower productivity of green and dry biomass (respectively 1310.77 kg ha-1 and 380.90 kg ha-1) compared to the grasslands of the plains (2430.72 kg ha-1 and 740.66 kg ha-1 respectively). The green biomass yield from the natural pastures, object of study, ranges from 920.38 kg ha-1 (Np 2) to 3000.13 kg ha-1. The dry mass yield is from 290.02 kg ha-1 (Np2) to 780.67 kg ha-1 (Np 4).

Climate change effects on pasture-based dairy systems in south-eastern Australia

Increases in temperature, along with possible decreases in rainfall, will influence the production of forage on Australian dairy farms. A biophysical simulation study was undertaken to compare the performance of perennial pastures and annual forage cropping systems under a historical scenario and two possible future climate scenarios for three key dairy locations of south-eastern Australia. Pastures and forage-cropping systems were simulated with the biophysical models DairyMod and APSIM, respectively, for a location with a heavy reliance on irrigation (Dookie, Victoria), a location with a partial reliance on irrigation (Elliott, Tasmania), and a dryland location (Terang, Victoria). The historical climate scenario (baseline scenario) had no augmentation to climate data and an atmospheric CO2 concentration of 380 ppm, whereas the two future climate scenarios had either a 1°C increase in temperatures (with an atmospheric CO2 concentration of 435 ppm) and a concurrent 10% decrease in rainfall, or a 2°C increase in temperatures (with an atmospheric CO2 concentration of 535 ppm) and a concurrent 20% decrease in rainfall. At Dookie, mean annual dry matter yields of the forage-cropping options and the pasture systems increased under both future climate scenarios but more irrigation was required. At Terang, the yield of forage-cropping systems increased whereas the yield of the pasture systems decreased under the future climate scenarios. At Elliott, yields of irrigated pastures and cropping systems increased but there was minimal or a negative impact on yields of dryland pastures and cropping systems under the future climate scenarios. At all three locations, forage production increased in the colder months of the year with a decrease in production during the warmer months. This study indicates that double-cropping and irrigated-pasture systems at all three locations appear resilient to projected changes in climate; however, for irrigated systems this assumes a reliable supply of irrigation water. The systems implications of how a shift in the seasonality of forage supply within these options impacts on the farm system as a whole warrants further investigation.

Mapping management zones in a sandy pasture soil using an objective model and multivariate techniques

Soils occupied by dryland pastures usually have low fertility but can exhibit a high spatial variability. Consequently, logical application of fertilisers should be based on an appropriate knowledge of spatial variability of the main soil properties that can affect pasture yield and quality. Delineation of zones with similar soil fertility is necessary to implement site-specific management, reinforcing the interest of methods to identify these homogeneous zones. Thus, the formulation of the objective Rasch model constitutes a new approach in pasture fields. A case study was performed in a pasture field located in a montado (agrosilvopastoral) ecosystem. Measurements of some soil properties (texture, organic matter, nitrogen, phosphorus, potassium, cation exchange capacity and soil apparent electrical conductivity) at 24 sampling locations were integrated in the Rasch model. A classification of all sampling locations according to pasture soil fertility was established. Moreover, the influence of each soil property on the soil fertility was highlighted, with the clay content the most influential property in this sandy soil. Then, a clustering process was undertaken to delimit the homogeneous zones, considering soil pasture fertility, elevation and slope as the input layers. Three zones were delineated and vegetation indices (normalized difference vegetation index, NDVI, and normalized difference water index, NDWI) and pasture yield data at sampling locations were employed to check their differences. Results showed that vegetation indices were not suitable to detect the spatial variability between zones. However, differences in pasture yield and quality were evident, besides some key soil properties, such as clay content and organic matter.