Pasture Dry Matter Yield Research Articles

Effects of heading date and Epichloë endophyte on persistence of diploid perennial ryegrass (Lolium perenne). 2. Endophyte strain and interactions with heading date

Context Data are lacking on the effects of selected endophytes of perennial ryegrass (Lolium perenne L.) on ryegrass persistence. Aim We aimed to determine the impact of Epichloë endophyte on the persistence of mid- and late-heading perennial ryegrass cultivars. Method Two mid-heading (Samson, Bronsyn) and two late-heading (One50, Rohan) cultivars, infected with selected endophytes (AR37, nea2/6) or with standard toxic endophyte, were established in a replicated plot study grazed by cattle in a subtropical environment of the upper North Island of New Zealand. Persistence characteristics were quantified at least five times per annum, over 4 years. Key results Endophyte strain had an effect on persistence; infection with standard endophyte resulted in higher ryegrass ground cover percentage, ryegrass content in pasture dry matter and autumn yield than infection with nea2/6 on many occasions, and with AR37 on some occasions. There were negligible impacts on ryegrass tiller density or nutritive value. Trends were dominated by the main effect of endophyte; interactions with heading date were inconsistent. Conclusions Cultivars were more persistent when infected with standard endophyte than with selected endophytes, although persistence declined over 4 years for all cultivars and irrespective of heading date. Implications Reliance on selected endophyte is unlikely to prevent persistence decline of perennial ryegrass in a subtropical environment. Other strategies will be required to maintain the persistence of high-quality pastures based on perennial ryegrass.

Simulating Gibberellic Acid Effect on Pasture Yield on Naturally Deposited and Fixed Area Urine

Nitrate (NO3−-N) leaching from urine patches is a serious environmental concern in dairy pastoral systems. In our previous research, we established that application of a plant growth hormone, gibberellic acid (GA), can potentially reduce NO3−-N leaching in urine patches; however, this was investigated in two locations in New Zealand. The performance of GA in influencing pasture nitrogen (N) uptake and NO3−-N leaching needs to be undertaken in multi-locations to draw conclusions. However, multi-location studies are a challenge due to a lack of funding and time constraints, so models such as the agricultural production systems simulator (APSIM) have been used. Therefore, field studies were conducted to determine whether APSIM can be used to quantify and simulate the effect of GA on NO3−-N leaching and pasture yield in three experimental sites known as Ashburton, Stratford, and Rotorua in New Zealand. Treatments examined were control (no urine applied), urine at 600 kg N ha−1, urine + GA at 8 g ha−1. The observed data was used to calibrate and validate the model. APSIM simulated that application of GA reduced NO3−-N leaching (relative to urine treatment) by 4.6, 5.1, and 8.8 kg NO3−-N ha−1 in Ashburton, Stratford, and Rotorua, respectively. APSIM reliably simulated pasture dry matter yield, and this was confirmed by the coefficient of determination ranging from R2 = 0.8562 to 0.995 in all treatments and experimental sites. This study demonstrated that APSIM can effectively be used to simulate the effect of GA application on NO3−-N leaching and pasture yield. Therefore, APSIM can be applied in other areas to simulate NO3−-N leaching and pasture yield.

The contribution of perennial ryegrass (Lolium perenne L.) breeding to whole pasture productivity under dairy cattle grazing in New Zealand. 2. Rates of gain in production traits and economic value

AbstractPerennial ryegrass (Lolium perenne) plant breeding has delivered several high performing and broadly adapted cultivar‐endophyte (Epichloë) combinations for the New Zealand pasture‐based livestock industries. However, the trends in key traits and the potential economic value being added to farm systems have not previously been addressed systematically. Rates of gain in yield, nutritive value, phenological and morphological traits, and the economic value of those traits, were estimated among and within ryegrass functional groups (heading date, ploidy) traded commercially between 1973 and 2012. Whole pasture dry matter yield improvements of c. 80 and 60 kg DM/ha per year were identified in in late‐season heading diploids and tetraploids respectively. Trends in metabolisable energy were negative within functional groups, but positive when all cultivar‐endophyte combinations were included in the analysis due to the addition of tetraploids and late‐season heading diploids from the mid‐1990s. The estimated trend in overall economic value (all cultivar‐endophyte combinations included) was $7/ha per year based on DM yield only, about half the rate of gain previously estimated using small‐plot merit testing data. The trend increased to $15/ha per year when ME was included due to the emergence of commercial tetraploids from the early 2000s onwards. Estimated economic gains were high within late‐season heading diploids and tetraploids but not mid‐season diploids. These trends suggest that, if high performing cultivar‐endophyte combinations had been adopted in New Zealand dairy systems, then pasture utilization should have increased by ~1 t DM/ha above the current industry average. Reasons for this apparent discrepancy are discussed.

The effect of fertilizer nitrogen input to grass-clover swards and calving date on the productivity of pasture-based dairy production

The objective of this systems-scale study was to investigate grazing season timeframes on pasture and milk production and on milk processability of dairy systems with compact spring-calving dairy cows grazing white clover (Trifolium repens L.) based grassland. Fifty-four primiparous and multiparous Holstein-Friesian dairy cows were used in a one-factor study with 3 systems (n = 18) and repeated over 2 yr (2008/09 and 2009/10). The 3 systems were: early spring calving with annual fertilizer N input of 100 kg·ha-1 applied in spring (ES100N; 2.1 cows·ha-1; grazing February to November), early spring calving without fertilizer N (ES0N; 1.6 cows·ha-1; grazing February to November) and late spring calving without fertilizer N (LS0N; 1.53 cows·ha-1; grazing April to January). Annual pasture production was affected by an interaction between grazing system and year: Mean annual pasture yields for 2008 and 2009 were ES100N; 10.35 and 9.88, ES0N; 8.88 and 8.63, LS0N; 9.18 and 10.31 t of dry matter (DM)·ha-1 (SEM 0.39). LS0N had higher pasture DM yield in 2009 due to higher clover DM production and biological N fixation compared with the other systems. Clover stolon and root mass in the following February was correlated with stolon and root mass in the previous November with 64% of stolon mass present on LS0N in February (R2 = 0.84). There were no detectable differences in per-lactation milk yield (6,335 kg·cow-1), fat, protein and lactose yields (271, 226, 297 kg·cow-1, respectively), cow liveweight (585 kg) or body condition score (3.02). Although winter grazing favored subsequent clover DM production, biological N fixation and pasture DM production, delaying calving date in spring and extending lactation into the following winter led to inefficient use of this pasture by the grazing herd and lowered the quality of late-lactation milk for processing purposes. Hence, a mean calving date in mid- to late-February is recommended for zero-fertilizer N input clover-based grassland.

Temporal response of ureolytic and ammonia-oxidizing microbes and pasture yield to urea and NBPT at Leigh Creek of Victoria in Australia

The urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) has been reported to effectively reduce nitrogen (N) losses by inhibiting urea hydrolysis. However, the effect of NBPT on soil ureolytic and ammonia-oxidizing microbes is not well understood, with inconsistent effects on crop yield and nitrogen use efficiency (NUE). Further, repeated use or overuse of chemical fertilizers can have environmental implications like soil acidification. A field experiment was conducted at Leigh Creek, Victoria at a site with a history of repeated application of urea alone (40U) or with NBPT (as Green Urea NV® (40GU)) at 40 kg N ha−1, and urea applied at 80 kg N ha−1 (80U), to perennial ryegrass (Lolium perenne L.). We aimed to investigate the temporal effects of NBPT applied with urea on ureolytic and ammonia-oxidizing microbes, pasture dry matter (DM) yield, and NUE within a season following treatment applications. The abundance of ureolytic microbes was higher in the control (CK) compared to all N treatments on all sampling days. The ureC gene copy numbers in 40 GU were significantly lower than in 40U on sampling days seven and 45. There was no significant effect of NBPT on the abundance of ammonia oxidizers, but increasing urea application rate to 80 kg N ha−1 (80U) significantly increased the abundance of ammonia-oxidizing bacteria (AOB) on days 7 and 45, and complete ammonia oxidizers (comammox Nitrospira) clade B on day 7 compared to 40U. There was no significant effect of NBPT on pasture DM yield, N-uptake, or NUE. Increasing N application rate significantly increased pasture DM yield and N- uptake but this did not influence the pasture NUE.

Mapping variability of pasture sward height, dry matter availability and disappearance during grazing

This study investigated whether geostatistical methods can be applied to severely drought-affected pastures to assess spatial variability in sward height (SH) and dry matter yield (DMY) and change in SH and DM in response to grazing. Geo-referenced SH data were collected using a rapid, non-destructive method (rapid pasture meter) and analysed by geostatistical methodology. Eight severely drought-affected paddocks (~1.25 ha) were grazed individually by two groups of 20 Angus heifers in two 28-day phases (P1 and P2) between 2 July and 29 August 2019. Pasture DMY was estimated from calibration equations developed for P1 and P2. Ordinary kriging was used to generate estimated surface forming maps with which to visualise the spatial variability. The degree of spatial dependence (dSD) was strongest for SH during P2 post-grazing (11%) and for DMY during P2 pre-grazing (6%). For change in SH, the dSD was 50% for P1 and 0% for P2. Disappearance of DMY dSD was 56% for P1 and 47% for P2. The range of spatial dependence (distance until variability stabilised) for both SH and DMY was lowest for P1 post-grazing (11 m), indicating that intensive sampling is required. The ranges of spatial dependence for the change in both SH and DMY were similar for P1 and P2. These results confirm that intensity of grazing by cattle is not random. Incorporation of this methodology into rapid, non-destructive pasture data collection devices would assist producers and their advisers in improving grazing management decisions. Further analysis with data from non-drought affected pastures is required to determine the robustness of this method.

Use of traditional, modern, and hybrid modelling approaches for in situ prediction of dry matter yield and nutritive characteristics of pasture using hyperspectral datasets

To optimise grazing livestock nutrition, it is necessary to know both the available dry matter yield and the nutritive characteristics of pasture at the farm-scale in near real time. Previous studies have shown the potential of using field spectrophotometers that measure the reflectance of light across the visible to near infrared spectrums to gather information on pasture dry matter yield (DMY) and nutritive characteristics. This study sought to calibrate and validate new mathematical models for ten parameters including dry matter yield and nine nutritive characteristics of relevance to ruminant nutrition. As a part of the analysis process, two innovative approaches were tested: the use of a hybrid modelling approach where partial least squares regression (PLSR) outputs were used as support vector regression (SVR) inputs; and, the inclusion of covariate data. These approaches were compared with traditional stand-alone PLSR and SVR modelling approaches without covariates. The study was undertaken in six predominantly perennial ryegrass pastures on a single farm in the temperate zone of South-Eastern Australia. A total of 204 pasture samples were scanned with a field spectrophotometer over several spring growth stages in late 2019 and subsequently analysed by wet chemistry to obtain reference nutritive values. The raw reflectance spectra were initially pre-processed using a variety of techniques and then used to test the four kinds of chemometric models. In cross validation, hybrid models showed a superior fit for all variates in comparison to the other model types tested. However, the differential was reduced in independent validation where, out of 10 best-performing models for dry matter yield and key nutrient properties, six were produced by the hybrid modelling, three from SVR and one from PLSR. For every hybrid model that was built, adding covariate(s) consistently improved model performance but the increase was small (a reduction in normalised root mean square error (RMSE) of -0.36 % on average for all properties considered). The best performing models were comparable with other published literature with normalised RMSE of prediction ranging from 1.7 – 23.1 % (a mean of 9.7%). Well-predicted variates included metabolisable energy, digestible energy, DMY, and crude protein. Fibre fractions, ash and dry matter were less well-predicted but still had acceptable normalised RMSE values (< 10 %) while carbohydrate fractions were the poorest predicted variates. It was concluded that hybrid modelling in chemometric analyses can modestly improve accuracy and shows promise as an alternative to more traditional approaches. Using covariates also improved accuracy, but the additional time and effort to gather such information outweighed the minor benefits of inclusion.

The Fusion of Spectral and Structural Datasets Derived from an Airborne Multispectral Sensor for Estimation of Pasture Dry Matter Yield at Paddock Scale with Time

This study aimed to develop empirical pasture dry matter (DM) yield prediction models using an unmanned aerial vehicle (UAV)-borne sensor at four flying altitudes. Three empirical models were developed using features generated from the multispectral sensor: Structure from Motion only (SfM), vegetation indices only (VI), and in combination (SfM+VI) within a machine learning modelling framework. Four flying altitudes were tested (25 m, 50 m, 75 m and 100 m) and based on independent model validation, combining features from SfM+VI outperformed the other models at all heights. However, the importance of SfM-based features changed with altitude, with limited importance at 25 m but at all higher altitudes SfM-based features were included in the top 10 features in a variable importance plot. Based on the independent validation results, data generated at 25 m flying altitude reported the best model performances with model accuracy of 328 kg DM/ha. In contrast, at 100 m flying altitude, the model reported an accuracy of 402 kg DM/ha which demonstrates the potential of scaling up this technology at farm scale. The spatial-temporal maps provide valuable information on pasture DM yield and DM accumulation of herbage mass over the time, supporting on-farm management decisions.

Evaluation of the Effect of Dolomitic Lime Application on Pastures—Case Study in the Montado Mediterranean Ecosystem

The Montado ecosystem, predominant in the Mediterranean region, consists of poor soils, a sparse cover of cork and holm with an understory of natural biodiverse pastures, grazed by animals in extensive regime. The recommended procedure for increasing productivity of these pastures is based on the application of phosphate fertilizer. One of the main productivity-limiting factors is, however, associated with soil acidity. The objective of this work was to evaluate the simultaneous effect of the holm oak canopy and the application of dolomitic lime on the productivity and quality of a permanent biodiverse pasture, grazed by sheep, in an acid soil (pH = 5.4 ± 0.3). Pasture was monitored at the end of autumn 2018 and winter and spring 2019. The results show that amendment of soil acidity is a slow and gradual process that improves soil Mg/Mn ratio and has a positive impact on pasture productivity and quality. Pasture crude protein availability (CP, kg·ha−1), which is based on both pasture dry matter yield (kg·ha−1) and quality (CP, %), proved to be a very practical indicator of the contributions of tree canopy and soil acidity correction to the holistic management of the Montado ecosystem.

Effect of Increasing Species Diversity and Grazing Management on Pasture Productivity, Animal Performance, and Soil Carbon Sequestration of Re-Established Pasture in Canadian Prairie.

Simple SummaryCanadian grasslands are recognized for providing high quality forage for grazing livestock and wildlife. The study was conducted on a re-established pasture in a Western Canadian semi-arid climate to investigate the effect of pasture species mixture and grazing management on pasture productivity, animal performance, and soil carbon sequestration. Pasture productivity and animal response were independent of pasture mixture but affected by grazing management. Average pasture dry matter productivity was greater with deferred-rotational grazing while pasture quality and animal gain were higher with continuous grazing. Soil carbon change varied with pasture seed mixture and grazing management interaction where pasture with 7-species mixture under continuous grazing had the lowest soil carbon gain. The objective of the study was to determine the effect of type of pasture mix and grazing management on pasture productivity, animal response and soil organic carbon (SOC) level. Pasture was established in 2001 on 16 paddocks of 2.1 ha that had been primarily in wheat and summer fallow. Treatments consisted of a completely randomized experimental design with two replicates: two pasture mixes (7-species (7-mix) and 12-species (12-mix)) and two grazing systems (continuous grazing (CG) and deferred-rotational grazing (DRG)). Pasture was stocked with commercial yearling Angus steers (Bos Taurus, 354 ± 13 kg) between 2005 and 2014. All pastures were grazed to an average utilization rate of 50% (40% to 60%). Average peak and pre-grazing pasture dry matter (DM) yield and animal response were independent of pasture seed mixture but varied with grazing management and production year. Average peak DM yield was 26.4% higher (p = 0.0003) for pasture under DRG relative to CG (1301 kg ha−1). However, total digestible nutrient for pasture under DRG was 4% lower (p < 0.0001) as compared to CG (60.2%). Average daily weight gain was 18% higher (p = 0.017) for CG than DRG (0.81 kg d−1), likely related to higher pasture quality under CG. Soil carbon sequestration was affected by seed mixture × grazing system interaction (p ≤ 0.004). Over the fourteen years of production, pasture with 7-mix under CG had the lowest (p < 0.01) average SOC stock at 15 cm (24.5 Mg ha−1) and 30 cm depth (42.3 Mg ha−1). Overall, the results from our study implied that increasing species diversity for pasture managed under CG may increase SOC gain while improving animal productivity.

The development and application of functions describing pasture yield responses to phosphorus, potassium and sulfur in Australia using meta-data analysis and derived soil-test calibration relationships

An improved ability to predict pasture dry matter (DM) yield response to applied phosphorus (P), potassium (K) and sulfur (S) is a crucial step in determining the production and economic benefits of fertiliser inputs and the environmental benefits associated with efficient nutrient use. The adoption and application of soil testing can make substantial improvements to nutrient use efficiency, but soil test interpretation needs to be based on the best available and most relevant experimental data. This paper reports on the development of improved national and regionally specific soil test–pasture yield response functions and critical soil test P, K and S values for near-maximum growth of improved pastures across Australia. A comprehensive dataset of pasture yield responses to fertiliser applications was collated from field experiments conducted in all improved pasture regions of Australia. The Better Fertiliser Decisions for Pastures (BFDP) database contains data from 3032 experiment sites, 21918 yield response measures and 5548 experiment site years. These data were converted to standard measurement units and compiled within a specifically designed relational database, where the data could be explored and interpreted. Key data included soil and site descriptions, pasture type, fertiliser type and rate, nutrient application rate, DM yield measures and soil test results (i.e. Olsen P, Colwell P, P buffering, Colwell K, Skene K, exchangeable K, CPC S, KCl S). These data were analysed, and quantitative non-linear mixed effects models based upon the Mitscherlich function were developed. Where appropriate, disparate datasets were integrated to derive the most appropriate response relationships for different soil texture and P buffering index classes, as well as interpretation at the regional, state, and national scale. Overall, the fitted models provided a good fit to the large body of data, using readily interpretable coefficients, but were at times limited by patchiness of meta-data and uneven representation of different soil types and regions. The models provided improved predictions of relative pasture yield response to soil nutrient status and can be scaled to absolute yield using a specified maximal yield by the user. Importantly, the response function exhibits diminishing returns, enabling marginal economic analysis and determination of optimum fertiliser application rate to a specific situation. These derived relationships form the basis of national standards for soil test interpretation and fertiliser recommendations for Australian pastures and grazing industries, and are incorporated within the major Australian fertiliser company decision support systems. However, the utility of the national database is limited without a contemporary web-based interface, like that developed for the Better Fertiliser Decisions for Cropping (BFDC) national database. An integrated approach between the BFDP and the BFDC would facilitate the interrogation of the database by advisors and farmers to generate yield response curves relevant to the region and/or pasture system of interest and provides the capacity to accommodate new data in the future.

Yield of Soybean in Different Systems of Pasture Replacement With and Without Soil Scarification

The objective of this work was to adjust the physical environment in sandy soils in no-tillage, to allow for the better development and yield of soybean, under water deficient conditions. The experiment was conducted at the Experimental Farm of The University of Western São Paulo in Presidente Bernardes, SP, 22º28'09'' S, 51º67'48'' W, 400 m asl. The experimental design constitued of two blocks each for the study variable: soil scarification, and no soil scarification. Each block was divided into 4 sub-blocks/treatments (control-natural seed bank of Urochloa brizantha-NSB; Urochloa brizantha broadcast seeding; Urochloa brizantha in line seeding; Urochloa brizantha in line seeding with soybean intercropped) with four replicates. As a plot, four systems of reimplantation of pasture with 4 kg ha-1 of Urochloa brizantha (Marandu cv.). Evaluated parameters: dry matter yield of pasture; yield components and soybean yield. The variables analyzed in each treatment were submitted to analysis of variance (p &lt; 0.05) and as means were compared by the Tukey test (p &lt; 0.05) using the Sisvar software. Considering the results obtained in the following research, it can be concluded that, according to the different pasture reimplatation systems, the treatment (in-line + soybean) contributed both to the increase of the dry matter of fodder, and to a yield of Soybean. Regarding the effect of soil scarification, none of the results were significantly influenced.

Predicting pasture yield response to nitrogenous fertiliser in Australia using a meta-analysis-derived model, with field validation

An improved ability to predict pasture dry matter (DM) yield response to applied nitrogen (N) is a crucial step in determining the production and economic benefits of N fertiliser inputs with associated environmental benefits from reducing inefficient N fertiliser use. Pasture DM yield responses to applied N fertiliser from 920 independent field trial sites were used from a database repository of Australian fertiliser experiments. These data were analysed and a quantitative non-linear mixed-effects model based on the Mitscherlich function was developed. The fitted model provided a good fit to a large body of data (R2 = 0.92), using readily interpretable coefficients, including fixed effects for state by season, phosphorus status and harvest type (initial or residual), and nested random effects for location and trial or subtrial. The model was limited by patchiness of metadata, uneven representation of regions and few very high rates of applied N in the data. Nonetheless, model predictions were comparable with independent spring pasture DM responses to applied N fertiliser from subsequent field studies on three contrasting pastures on commercial dairy farms in Victoria. The final derived model can be used to predict pasture yield response to applied N fertiliser as a proportion of obtainable yield and can be scaled to absolute response using the fitted model estimates of maximal yield or, more usefully, a specified maximal yield by the user. Importantly, the response function exhibits diminishing returns, enabling marginal economic analysis and determination of optimum N fertiliser application rate to a specified pasture.

Effect of inter-annual variability in pasture growth and irrigation response on farm productivity and profitability based on biophysical and farm systems modelling

Farm system and nutrient budget models are increasingly being used in analysis to inform on farm decision making and evaluate land use policy options at regional scales. These analyses are generally based on the use of average annual pasture yields. In New Zealand (NZ), like in many countries, there is considerable inter-annual variation in pasture growth rates, due to climate. In this study a modelling approach was used to (i) include inter-annual variability as an integral part of the analysis and (ii) test the approach in an economic analysis of irrigation in a case study within the Hawkes Bay Region of New Zealand.The Agricultural Production Systems Simulator (APSIM) was used to generate pasture dry matter yields (DMY) for 20 different years and under both dryland and irrigation. The generated DMY were linked to outputs from farm-scale modelling for both Sheep and Beef Systems (Farmaxx Pro) and Dairy Systems (Farmax® Dairy Pro) to calculate farm production over 20 different years. Variation in DMY and associated livestock production due to inter-annual variation in climate was large, with a coefficient of variations up to 20%. Irrigation decreased this inter-annual variation. On average irrigation, with unlimited available water, increased income by $831 to 1195/ha, but when irrigation was limited to 250mm/ha/year income only increased by $525 to 883/ha. Using pasture responses in individual years to capturing the inter-annual variation, rather than the pasture response averaged over 20years resulted in lower financial benefits. In the case study income from irrigation based on an average year were 10 to >20% higher compared with those obtained from individual years.

Evaluating the use of plant hormones and biostimulators in forage pastures to enhance shoot dry biomass production by perennial ryegrass (Lolium perenne L.).

Fertilisation of established perennial ryegrass forage pastures with nitrogen (N)-based fertilisers is currently the most common practice used on farms to increase pasture forage biomass yield. However, over-fertilisation can lead to undesired environmental impacts, including nitrate leaching into waterways and increased gaseous emissions of ammonia and nitrous oxide to the atmosphere. Additionally, there is growing interest from pastoral farmers to adopt methods for increasing pasture dry matter yield which use 'natural', environmentally safe plant growth stimulators, together with N-based fertilisers. Such plant growth stimulators include plant hormones and plant growth promotive microorganisms such as bacteria and fungi ('biostimulators', which may produce plant growth-inducing hormones), as well as extracts of seaweed (marine algae). This review presents examples and discusses current uses of plant hormones and biostimulators, applied alone or together with N-based fertilisers, to enhance shoot dry matter yield of forage pasture species, with an emphasis on perennial ryegrass.

Bazı Yabancı Ot Mücadele Yöntemlerinin Akdeniz Bölgesi Meralarında Ot Verimi, Botanik Kompozisyon ve Ot Kalitesi Üzerine Etkisi

Araştırma, Çukurova Bölgesi’ndeki makiliklerin tahribi sonucu ortaya çıkan kıraç meralarda yabancı otlarla etkili mücadele yöntemlerinin belirlenmesi amacıyla 2006-2009 yılları arasında Mersin ili Toroslar ilçesi Resul köyü doğal merasında yürütülmüştür. Araştırma, tesadüf blokları deneme desenine göre 3 tekrarlamalı olarak yürütülmüştür. Denemede biçme, gübreleme, 2.4-D, Picloram+2.4-D, Paraquat ve Glyphosate uygulamaları incelenmiştir. Araştırma sonuçları, gübreleme uygulamasının meranın kuru madde ve sindirilebilir kuru madde verimlerini artırdığını göstermiştir. Tüm uygulama parsellerinde kuru madde verimi, kontrol parsellerindekine göre daha yüksek olmuştur. Picloram+2.4- D+gübreleme uygulaması buğdaygillerin botanik kompozisyondaki oranını artırırken baklagillerin oranını azaltmıştır. Paraquat+gübreleme uygulaması botanik kompozisyonda diğer familya bitkilerinin oranını artırmıştır. Picloram+2.4- D+gübreleme uygulaması otun NDF oranını artırmıştır. Araştırmadan elde edilen bulgulara dayanarak, Çukurova bölgesindeki makilerin tahribi sonucu ortaya çıkmış meralarda çoğunluğu geniş yapraklı bitkilerden oluşan yabancı otların Picloram+2,4-D uygulamasıyla etkin bir şekilde kontrol edilebileceği, bu tip meralarda yabancı ot kontrolü ile birlikte yapılacak gübre uygulamasının meranı ot verimi ve kalitesinde artışa neden olacağı sonucuna varılmıştır.

Spatial and temporal patterns of potassium on grazed permanent pastures—Management challenges

Alto Alentejo region in Southern Portugal has over 200,000ha of grazing permanent pastures. Here, the soils do not generally need potassium (K) fertilization due to the bedrock richness in K. The general objective of this study was to evaluate the specificity of the spatial and temporal soil test K dynamics, over 10 years, in a complex agro ecosystem (a bio-diverse pasture installed on a shallow soil, grazed by sheep, in Mediterranean conditions) and the potential for implementing site specific fertilizer management. A 6ha permanent pasture field was subject to two management systems: (i) 2004–2007, the field was used for grazing by sheep and improved by an annual application of super phosphate fertilizer 18%; (ii) 2007–2013, the field was left fallow. The K spatial trend and K temporal stability were evaluated by a single map of management classes. The evolution of mean soil test K concentration in the experimental field over the 10-year study ranges, in relative terms, between −21% and +16% of the overall average of the period considered (96±21mgkg−1). This study, however, shows that the experimental field is dominated by a large spatially anisotropic trend. Significant correlation coefficients were found between the soil test K concentration and altimetry (0.614), clay (0.651), sand (−0.674), test phosphorus (P) concentration (0.749), organic matter (0.882), soil moisture content (0.455), apparent soil electrical conductivity (0.436) and pasture dry matter yield (−0.499). It can be stated that the combined effects of an undulated landscape, with sparse trees and animals that selectively graze the plant species and make a heterogeneous deposition of dung and urine, provide a notable spatial variability of soil test K concentration (Spatial_CV¯ of 29.8±12.3%). The K temporal stability (Temporal_CV¯ = 18.1±8.6%), is confirmed by the predominance of moderately stable (56.6% of the experimental field) and of stable areas (25.0% of the experimental field). Within the classes identified as moderately stable and stable, around 45% of the experimental field shows soil test K concentrations below average soil test K concentration. Based on regional recommendation of 125–150mgkg−1 of K in the soil to adequately promote the development of dry-land permanent pastures, this study demonstrates the interest and the potential for using variable rate technology (VRT) for site-specific K management in pastures in Southern Portugal.

Improving ryegrass‐clover pasture dry matter yield and urea efficiency with gibberellic acid

The effects of spraying gibberellic acid (GA3) at 20 or 30 g ha(-1), with or without application of urea, on pasture dry matter (DM) yield, herbage nitrogen (N) concentration and feed quality were investigated in 2011 and 2012 for managed pastoral systems in New Zealand across a range of sites, in both autumn and spring. On the Waikato site (autumn and spring, 2012), and at all five sites in 2011, liquid urea applied with GA3 at 20 or 30 g ha(-1) consistently produced significantly higher pasture shoot DM yield, relative to liquid urea alone. Application of GA3 alone reduced feed quality by lowering metabolizable energy, crude protein and organic matter digestibility values. However, a reduced feed quality was not observed when GA3 was applied together with liquid urea. Liquid urea applied with GA3 also reduced total N and nitrate-N concentration in herbage, relative to liquid urea applied alone. Application of GA3 together with liquid urea provides an opportunity for the strategic use of urea to meet both production and environmental goals.

Improving pasture growth and urea efficiency using N inhibitor, molybdenum and elemental sulphur

A one year field experiment was conducted to assess the efficiency of urea fertilizer applied to pasture near Lincoln University, New Zealand. Urea with or without (±) molybdenum (Mo) were applied to field plot, with a urease inhibitor (N-(n-butyl) thiophosphoric triamide (nBTPT), nBTPT + elemental sulphur (S), and nitrification inhibitor dicyandiamide (DCD) + nBTPT defined as a double inhibitor (DI) in spring 2005. Mo was sprayed at the rate of 50 g Mo/ha/yr once. Urea ± various inhibitor and S treatments were broadcast at a rate of 30 kg N/ha 5 times over one year. The Mo alone treatment increased pasture dry matter (PDM) yield by 8.9%. Molybdenum, when applied together with urea+nBTPT+S, urea+nBTPT and urea alone, caused an initial depression in PDM yield by 14.2, 13 and 5.6% respectively. However, these depressions in yield disappeared from the second pasture cut. Over a one year period, Mo applied with urea+nBTPT, urea+DI and urea+nBTPT+S produced 18179, 16716 and 18253 kg DM ha -1 respectively, compared to 16171 kg ha -1 for urea+Mo. Pastures which

Physical properties of a Red-Yellow Latosol and productivity of a signalgrass pasture fertilized with increasing nitrogen doses

The physical properties and fertility of the soil are important factors in the formation and establishment of pasture. Changes in physical properties affect the movement of water, air, nutrients and roots, which, in turn, affect the productivity and longevity of pastures. The objective of this study was to evaluate the physical properties of the soil and the dry matter yield of a pasture with signalgrass cv. Basilisk (Brachiaria decumbens cv. Basilisk), fertilized with increasing nitrogen doses (N), on a dystrophic Red-Yellow Latosol. The experiment was conducted on the Fazenda Rio Manso of the Universidade Federal dos Vales do Jequitinhonha e Mucuri, in Couto de Magalhães de Minas, State of Minas Gerais, Brazil. To evaluate the annual forage yield, a split plot scheme in a randomized block design with four replications was used, with N doses (0, 50, 100, 150, and 200 kg/ha/year) in the plots and growing seasons (first and second) in the subplots. For soil evaluation, a split plot scheme was used with N doses (0, 25, 50, 75 and 100 kg/ha/cut) in the plots and three sampling times (prior to the experiment, at the end of the first growing season and at the end of the second growing season) in the subplots in a randomized block design with four replications. This analysis was performed separately at two soil depths (0-3 and 10-13 cm). Forage samples were analyzed for the annual dry matter yield (DMY), and soil samples were analyzed for pre-consolidation pressure (σp), initial soil bulk density (Bd), total pore volume (TPV) and void index (Vd). Higher nitrogen doses increased the dry matter yield of signalgrass pasture and the pre-consolidation pressure of the soil. The total pore volume and void index decreased, and the initial soil bulk density increased, though without promoting soil compaction.