Grass Dry Matter Yield Research Articles

Clearfield upland rice intercropped with Urochloa ruziziensis for grain, increased revenue and environmental preservation

AbstractIntercropping perennial forage grasses into cereal crops is an alternative to recover degraded pastures. However, the intercrop of forage grasses, such as Urochloa ruziziensis (R. Germ. and C. M. Evard) Crins (Congo grass), can lead to losses in cereal yield. Therefore, it is necessary to develop management strategies that allow forage grass establishment without major losses in cereal yield in intercropping. The objective was to study the agronomic and economic impacts of intercropping U. ruziziensis into a Clearfield upland rice (Oryza sativa L.) cultivar in the state of Goiás, Brazil, in two growing seasons. Treatments included forage grass seeds sowing method (broadcast or incorporation to the soil) and sowing times (at rice sowing, 20 days after emergence [DAE], and 45 DAE of rice). Also, imazapyr + imazapic herbicide was applied to restrict the competitive effect on rice yield. Monocropping control plots were also evaluated. Grain yield was measured on rice. Forage grass dry matter yield was measured at 30, 60, and 90 days after harvesting (DAH) of rice. Crude protein content was analyzed at 90 DAH. Profitability was calculated for each cropping system relative to rice monocropping. Intercropping of rice and U. ruziziensis sowed at 45 DAE provided the highest grain yield relative to other assessed intercropping treatments as well as rice monocropping. Concurrent sowing of rice and incorporated U. ruziziensis seeding provided the greatest economic return. This reformed cropping system improved land and pasture output, which can reduce the pressure to convert more land to agricultural use.

Effects of organic and inorganic fertilizers on soil properties related to the regeneration of ecosystem services in peat grasslands

Worldwide, agricultural grasslands on drained peat contribute to CO2 emission but provide also provisioning and supporting ecosystem services that are managed by farmers. This paper evaluates the performance of organic and inorganic fertilizers in relation to soil biotic and abiotic properties linked to soil ecosystem services of peat grasslands with biodiversity goals. Effects of cattle slurry, compost, farmyard manure, solid fraction of cattle slurry and inorganic nitrogen (N) fertilizer with and without added sawdust were compared to those of an unfertilized control in a three-year field experiment. Total N input was targeted at 120 kg N ha−1 year−1; total carbon (C) input was variable due to different C:N ratios of source materials. The abundance of earthworms in spring was increased with solid fraction (+35 % as compared to the control), which had the largest C input, and was reduced with inorganic N (−24 %). Combining inorganic N with sawdust did not affect earthworm abundance. Bacteria (determined by phospholipid fatty acid analysis) were increased following inorganic N fertilizer application with (+65 %) or without (+52 %) sawdust. Arbuscular mycorrhizal fungi were reduced by all fertilizers (−40 to −88 %), but less so by those with large C input (solid fraction) or with lignin-rich C input (sawdust + inorganic N fertilizer). Physical and chemical soil properties related to water infiltration and soil organic matter (SOM) decomposition were marginally influenced by fertilizers. The measured changes in soil pH, P availability and (micro)biology may affect SOM dynamics in the longer term. Grass dry matter yield was similarly increased by all fertilizers (+7 to 11 %) whereas grass N yield was increased by fertilizers only when the applied N was in mineral form (+16 to 20 %). From our results, we propose that the moderate use of organic fertilizers with a high and non-humified organic matter content such as solid fraction of cattle slurry can be part of a regeneration strategy in peat grasslands with biodiversity goals.

XARAÉS GRASS UNDER DIFFERENT IRRIGATION DEPTHS TO RECOVER AREAS CONTAMINATED WITH IRON MINING TAILINGS

Iron mining tailings have limitations for plant growth and development due to low fertility, coupled with great restriction of physical characteristics such as low water retention, high density, and lack of structure. This study aimed to evaluate whether different irrigation depths applied to Xaraés grass grown in mining tailings influence its yield and bromatological aspects. The experiment was carried out in a completely randomized design with five irrigation depths (40, 60, 80, 100, and 120% of the crop evapotranspiration), two additional treatments consisting of grass grown in tailings with soil conditioner and in natural soil, and three repetitions. Forage dry mass, plant height, leaf: stem ratio, as well as neutral detergent fibre, acid detergent fibre, crude protein, and mineral matter content, were evaluated during four cutting cycles. Xaraés grass could establish and produce forage despite cultivation limitations in iron mining tailings, which are due to their properties. Irrigation depths showed positive and linear effects on Xaraés grass dry matter yield and heights of plants grown in iron mining tailings. The soil conditioner has potential for use in pasture cultivation in iron mining tailing.

Integration of multicriteria decision analysis and geographic information system for site suitability assessment of Napier grass-based biogas power plant in southern Thailand

Napier grass is a promising energy crop owing to its advantages over other energy crops; however, when determining sites for the power plants utilizing Napier grass as a feedstock, relevant data are required. The spatial distribution of the Napier grass dry matter yield (DMY) is among these important data. Unlike agricultural residues, the spatial distribution of the DMY cannot be obtained through surveys or statistical data. In this study, a methodology for locating biogas power plants utilizing Napier grass as a feedstock is proposed. A geographic information system and analytic hierarchy process are used to evaluate land suitability for biogas power plants based on environmental and socioeconomic criteria. The spatial distribution of the DMY is integrated with the land suitability map to locate suitable sites for biogas power plants. The proposed approach is applied to southern Thailand because the region lacks self-sufficient power generation. The results reveal that, five biogas power plants that utilize Napier grass from abandoned areas can be established with a total contracted capacity of 420 MW. Based on this analysis, introducing Napier grass-based biogas power plants could significantly help reduce the dependency on imported electricity. Stakeholders are recommended to treat this study as a tool to be utilized before implementing new dedicated energy crops.

Land Potential Assessment of Napier Grass Plantation for Power Generation in Thailand Using SWAT Model. Model Validation and Parameter Calibration

In Thailand, Napier grass is expected to play an important role as an energy resource for future power generation. To accomplish this goal, numerous areas are required for Napier grass plantations. Before introducing crops, the land potential of the country and the impact of crops on the environment should be assessed. The soil and water assessment tool (SWAT) model is very useful in investigating crop impacts and land potential. Unfortunately, the crop growth parameters of Napier grass are yet to be identified and, thus, conducting effective analysis has not been possible. Accordingly, in this study, parameter calibration and SWAT model validation of Napier grass production in Thailand was carried out using datasets from eight sites with 93 samples. Parameter sensitivity analysis was performed prior to parameter calibration, the results of which suggest that the radiation use efficiency and potential harvested index are both highly sensitive. The crop growth parameters were calibrated in order of their sensitivity index ranking, and the final values were obtained by reducing the root mean square error from 10.77 to 1.38 t·ha−1. The validation provides satisfactory results with coefficient of determination of 0.951 and a mean error of 0.321 t·ha−1. Using the developed model and calibrated parameters, local Napier grass dry matter yield can be evaluated accurately. The results reveal that, if only abandoned area in Thailand is used, then Napier grass can provide roughly 33,600–44,900 GWh of annual electricity, and power plant carbon dioxide (CO2) emissions can be reduced by approximately 21.2–28.3 Mt-CO2. The spatial distribution of estimated yield obtained in this work can be further utilized for land suitability analysis to help identify locations for Napier grass plantations, anaerobic digesters, and biogas power plants.

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 < 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 < 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.
 

Effect of cutting frequency and nitrogen application on herbage yield and nitrogen content of a degraded Panicum maximum pasture.

The effects of cutting frequency and levels of nitrogen on revitalization of a run-down pasture were investigated in 2000 and 2001 at Nsukka, Nigeria. Grass swards were cut at intervals of 3, 6, 9 and 12 weeks and received 0, 150, 300 and 450 kg N ha' nitrogen. Grass dry matter yield was increased from 52 to 75% at the 3 and 6 weeks intervals of cutting, respectively. Weed proportion was reduced from 48 to 25% with 6-weekly cuts compared with more frequent cutting at 3 weeks interval between cuts. Cutting interval did not affect the total herbage yield. The dry matter yields of leaf blade, stem and inflorescence fractions increased significantly with increase in interval between cuts in the second year. The percentage nitrogen content was highest with 3-weekly interval of cut and decreased with high interval of cuts in the second year. Crude protein yield (kg ha') was highest with 6- and followed by 3- and 9-weekly intervals of cut and decreased with lar cutting of 12-weekly interval. Fertilizer-N treatment significantly increased total annual herbage dry matter yield from 3,460 kg ha yrl where no fertilizer N was applied to 5,233 kg ha-yr' with application of 450 kg N ha-'. Grass dry matter as proportion of the total herbage dry matter was increased from 57 to 80% with the highest N rate of 450 kg Nha compared with where N was not applied, while the weed dry matter as proportion of the total herbage dry matter was reduced from 43 to 20% with the highest N rate of 450 kg N ha compared with where N was not applied at the second year. A combination of 6-weeks interval of cutting with 450 kg N ha' gave the highest dry matter yield. It was also adequate in suppressing weed. Frequent cutting at higher levels of fertilizer N (300 - 450 kg ha'') increased the nitrogen and crude protein percentages of forage foliage while 6-weekly interval of cuts when combined with higher N levels gave the highest crude protein yield per hectare per year in the foliage herbage.

Cool‐season grass productivity estimation model evaluating the effects of global warming and climate adaptation strategies

AbstractVarious climate adaptation strategies are being studied for the agricultural sector to address the effects of climate change. Global warming is predicted to have a significant influence on cool‐season grass production in Japan in terms of decreasing grass dry matter yield. The authors have studied adaptation strategies to maintain grass dry matter yield using orchardgrass, a cool‐season grass. However, it may be difficult to adapt to future climate conditions using management methods such as fertilizer application or changing grassland renovation cycles using only one grass species. In this study, a model was constructed formulating the relationship between temperature and yields of the main cool‐season grasses in Japan, and the effects of global warming on grass productivity were predicted. Two models were constructed, and the optimal one was selected using Akaike's information criterion. The selected model was then validated using correlations with observation data. We also compared areas suitable for cultivation at current and higher temperatures, which were produced as maps using the selected model. Bahiagrass, which is a warm‐season grass, was suitable for cultivation in coastal areas in southern Kanto under increased temperature condition. It may be useful, therefore, to convert to heat‐resistant grasses, such as orchardgrass or tall fescue, as temperatures rise.

Responses of soil microbiota and nematodes to application of organic and inorganic fertilizers in grassland columns

Enhancing the role of the soil microbiota in plant phosphorus (P) and sulfur (S) supply through application of organic fertilizer could reduce dependencies on non-sustainable synthetic fertilizers. To compare the effects of organic/inorganic fertilizers on the soil microbiota, soil columns with Lolium perenne (ryegrass) were set up in a greenhouse and amended with an inorganic fertilizer, cattle slurry (organic), or urea (P- and S-free control). Ryegrass rhizosphere of the slurry treatment had significantly higher abundances of bacterial feeding nematodes, mycorrhizal colonization, cultivable heterotrophic bacteria, phosphonate- and sulfonate-utilizing bacteria, arylsulfatase activity, available P, and Variovorax asfA gene copies compared to the inorganic and urea treatments. Phosphomonoesterase activities, and gene abundances involved in organic P and S transformations (phoD, phoC, Burkholderia, and Polaromonas asfA) were similar in all treatments. Grass dry matter yield and shoot uptake of N, P, and S were significantly higher in the inorganic treatment compared to the urea and slurry treatments. Community compositions differed significantly between the three fertilizer treatments and included the bacterial, alkaline phosphomonoesterase-producing bacterial, fungal, AM fungal, and nematode communities. Bacteriodetes were found in higher relative abundance in the organic treatment, while Acidobacteria were more abundant in the urea and inorganic fertilizer treatments. These community shifts correlated significantly with grass dry matter yield, uptake of N, P, and S, mycorrhizal colonization, enzyme activities, abundances of bacteria, and bacterial feeding nematodes. We concluded that organic fertilization promoted soil microbes and nematodes which have the potential to support sustainable plant growth, provided that the overall nutrient requirements are met.

Magnesium biofortification of Italian ryegrass (Lolium multiflorum L.) via agronomy and breeding as a potential way to reduce grass tetany in grazing ruminants

AimMagnesium (Mg) deficiency (known as grass tetany) is a serious metabolic disorder that affects grazing ruminants. We tested whether Mg-fertiliser can increase Mg concentration of Italian ryegrasses (Lolium multiflorum L.) including a cultivar (cv. Bb2067; ‘Magnet’), bred to accumulate larger concentrations of Mg.MethodsUnder controlled environment (CE) conditions, three cultivars (cv. Bb2067, cv. Bb2068, cv. RvP) were grown in low-nutrient compost at six fertiliser rates (0–1500 μM MgCl2.6H2O). Under field conditions, the three cultivars in the CE condition and cv. Alamo were grown at two sites, and four rates of MgSO4 fertiliser application rates (0–200 kg ha−1 MgO). Multiple grass cuts were taken over two-years.ResultsGrass Mg concentration increased with increasing Mg-fertiliser application rates in all cultivars and conditions. Under field conditions, cv. Bb2067 had 11–73% greater grass Mg concentration and smaller forage tetany index (FTI) than other cultivars across the Mg-fertiliser application rates, sites and cuts. Grass dry matter (DM) yield of cv. Bb2067 was significantly (p < 0.05) smaller than cv. Alamo. The effect of Mg-fertiliser rate on DM yield was not significant (p ≥ 0.05).ConclusionsBiofortification of grass with Mg through breeding and agronomy can improve the forage Mg concentration for grazing ruminants, even in high-growth spring grass conditions when hypomagnesaemia is most prevalent. Response to agronomic biofortification varied with cultivar, Mg-fertiliser rate, site and weather. The cost:benefit of these approaches and farmer acceptability, and the impact on cattle and sheep grazing on grasses biofortified with Mg requires further investigation.

Sulfate fertilization supports growth of ryegrass in soil columns but changes microbial community structures and reduces abundances of nematodes and arbuscular mycorrhiza

The increased use of sulfate fertilizers to compensate for soil sulphur (S) limitation in agricultural soils may affect soil microbes and micro-fauna involved in S mobilization. Here, columns with podzolic soil material and ryegrass (Lolium perenne) were fertilized with 0, 5, 10 and 20 kg ha−1 (S0/S5/S10/S20) inorganic sulfate-S alongside a full complement of other nutrients. In the S10 and S20 columns, significantly higher amounts of sulfate were present in soil solution. After two grass cuts (14 weeks in total), there was a significant decrease in arylsulfatase activity, bacterial-feeding nematode abundances and mycorrhizal colonization in the S10 and S20 columns compared to the S0. Bacterial, fungal and AM community structures shifted significantly across the treatments. After final harvest, the S10 and S20 columns had significantly higher grass dry matter yield and uptake of S, N, K, Ca and Mg compared to the S0. While the overall bacterial diversity was reduced in the S20 treatment, abundance (asfA) and diversity (ssuD and atsA) of bacterial genes involved in S cycling were not significantly affected by one-time sulfate fertilization. These results indicate that short-term sulfate fertilization benefits to plant growth outweighed the negative feedback from parts of the soil biota. To improve nutrient use efficiencies in a sustainable manner, future studies should consider alternative S fertilizers which may be beneficial to both, the soil biota and plants in the long-term.

Effects of fertiliser nitrogen rate to spring grass on apparent digestibility, nitrogen balance, ruminal fermentation and microbial nitrogen production in beef cattle and in vitro rumen fermentation and methane output

The effects of two fertiliser nitrogen (N) application rates - 15 (LN) or 80 (HN) kg N/ha - to Lolium perenne dominant swards in spring, on grass dry matter (DM) intake, digestion, rumen fermentation, microbial N production and N-balance in beef cattle, and in vitro fermentation and methane production were studied. Sixteen Charolais steers with a mean live weight (s.d.) of 475 (18.4) kg, were used in a completely randomised block design experiment and offered zero-grazed grass harvested 21-d post N application. The same grass was incubated in an eight-vessel RUSITEC in a completely randomised block design experiment. The HN treatment had a 540 kg/ha higher grass DM yield, and a 20 g/kg DM higher crude protein (CP) concentration compared to LN. There was no difference (P > 0.05) in DM intake, or in vivo DM, organic matter (OM) and N digestibility between treatments. Rumen fermentation variables pH, lactic acid, ammonia (NH3) and total volatile fatty acid (VFA) concentration were similar (P > 0.05) for both treatments. Nitrogen intake was 19 g/d higher (P < 0.05) for HN compared to LN. Total and urine N loss was 16 and 14 g/d greater (P < 0.05), respectively, for HN compared to LN, but faecal N loss did not differ (P > 0.05) between treatments. The quantity of N retained and N-use efficiency did not differ (P > 0.05) between LN and HN. Plasma urea concentration was 1 mmol/L greater (P < 0.05) for HN compared to LN. Estimated microbial N production was greater (P < 0.05) for HN compared to LN. In vitro NH3 concentrations were higher (P < 0.05) for HN compared to LN, whereas in vitro rumen pH, lactic acid and VFA concentrations and molar proportions did not differ (P > 0.05) between HN and LN. In vitro methane and total gas output were not different (P > 0.05) between treatments. Reducing fertiliser N application rate to grass in spring reduced total and urinary N excretion, which has environmental benefits, with no effects on in vitro methane output.

Improving grass silage production with controlled traffic farming (CTF): agronomics, system design and economics

Grassland silage management is generally semi-organised with no conscious attempt to re-use wheel ways as with arable fields. The total number of machine passes can be 15 or more with normal traffic (NT) systems resulting in potentially large areas of a field suffering from direct damage to the crop and soil. Literature suggests there can be grass dry matter yield reductions of 5 to 74% under NT through compaction and sward damage, with a mean of 13% in the UK. Commercially available grass forage equipment with widths of 3 to 12 m set up for controlled traffic farming (CTF) could reduce trafficked areas (which is typically 90% to 80% for NT) to 40% to 13% for CTF. This study compared grass dry matter yield between CTF and NT for a three-cut silage system based on a 9 m working width in a permanent silage field in the southwest of Scotland, UK in 2015. Results showed a 13.5% (0.80 t ha−1) increase in yield for CTF for the 2nd and 3rd cuts combined. The CTF trafficked area covered was 57% less than the NT system (30.4% compared to 87.4%) over the three silage cuts. An economic analysis based on a 13% increase in dry matter yield (for 2- and 3-cut systems) and a reduction in trafficked area from 80% (for NT) to between 45% and 15% (for CTF), increased the yield by between 0.53 t ha−1 and 1.36 t ha−1 for 2- and 3-cut systems, respectively with an equivalent grass value of between £38 ha−1 and £98 ha−1. Introducing CTF for a multi-cut grass silage system is cost-effective by increasing yields due to a reduction in compaction and sward damage.

Yield of Native Warm‐Season Grasses in Response to Nitrogen and Harvest Frequency

Core Ideas Within year, harvest frequency has the greatest effect on DM production of native warm‐season grasses. Nitrogen has little effect on native warm‐season grass DM yield. Eastern gamagrass can tolerate consecutive years of frequent defoliations and maintain yield. Five native warm‐season grass species and mixtures were grown in east‐central Mississippi on a coarse‐loamy, siliceous, semiactive, thermic Glossic Fragiudult, to determine their potential as forage grasses in response to harvest frequency and N application. Established stands were harvested at 30, 40, 60, and 120 d intervals, and were fertilized with N rates of 0, 56, 112, 168, and 224 kg N ha−1 for two consecutive years (2016 and 2017). Dry matter (DM) yield and agronomic nitrogen use efficiency (aNUE) were analyzed. Year, treated as a repeated measure, was the main source of variation affecting DM yields. Within year, harvest frequency had the greatest effect on cumulative yields in 2016, accounting for 44% of the variation observed. This effect was not observed in 2017. Frequent defoliations led to overall lower yields in 2017. Nitrogen was significant, but moderately, accounting for 2 and 4% of variation for 2016 and 2017, respectively. Species was also significant for both years. Agronomic N use efficiency varied between year, species, N rate, and harvest frequency. Eastern gamagrass [Tripsacum dactyloides (L.) L.] was the only species in which cumulative DM yield remained consistent across both years of the study, regardless of harvest frequency or N application. Results suggest that rest periods should be based on species present, and that less frequent harvests are required for sustained DM yields.

Estimating Biomass and Nitrogen Amount of Barley and Grass Using UAV and Aircraft Based Spectral and Photogrammetric 3D Features

The timely estimation of crop biomass and nitrogen content is a crucial step in various tasks in precision agriculture, for example in fertilization optimization. Remote sensing using drones and aircrafts offers a feasible tool to carry out this task. Our objective was to develop and assess a methodology for crop biomass and nitrogen estimation, integrating spectral and 3D features that can be extracted using airborne miniaturized multispectral, hyperspectral and colour (RGB) cameras. We used the Random Forest (RF) as the estimator, and in addition Simple Linear Regression (SLR) was used to validate the consistency of the RF results. The method was assessed with empirical datasets captured of a barley field and a grass silage trial site using a hyperspectral camera based on the Fabry-Pérot interferometer (FPI) and a regular RGB camera onboard a drone and an aircraft. Agricultural reference measurements included fresh yield (FY), dry matter yield (DMY) and amount of nitrogen. In DMY estimation of barley, the Pearson Correlation Coefficient (PCC) and the normalized Root Mean Square Error (RMSE%) were at best 0.95% and 33.2%, respectively; and in the grass DMY estimation, the best results were 0.79% and 1.9%, respectively. In the nitrogen amount estimations of barley, the PCC and RMSE% were at best 0.97% and 21.6%, respectively. In the biomass estimation, the best results were obtained when integrating hyperspectral and 3D features, but the integration of RGB images and 3D features also provided results that were almost as good. In nitrogen content estimation, the hyperspectral camera gave the best results. We concluded that the integration of spectral and high spatial resolution 3D features and radiometric calibration was necessary to optimize the accuracy.

Evaluation of Grazing Land Condition in Gozamen District, East Gojjam Zone, Amhara Regional State, Ethiopia

The study was conducted in Gozamen district of East Gojam Zone of the Amhara region to assess the major feed resources, the grazing land condition, and the floristic composition and biomass yields of herbaceous species to generate baseline information which can be used for future management of grazing land resources in the area. The survey data was collected by interviewing a total of 120 households by random selection of two rural-kebeles from three altitudes [high, mid and low].To assess grazing land condition, the district was stratified into three altitudes [high, mid and low altitudes]. From each altitude, communal and enclosed grazing areas were selected randomly. From each altitude 8 composites and 12 composites from enclosed and 12 composites from communal grazing for herbaceous vegetation and 4 transects from each altitude of communal grazing were selected. Thus, a total of 72 quadrats were used for herbaceous and 12 transects for woody species. For the natural pasture condition assessment, analyses of variance [ANOVA] were carried out by the General Linear Model [GLM] procedure of SAS. Mean separation was tested using the least significant difference. The main feed resources to the livestock in all altitudes were natural pasture, crop residues and stubble grazing. During dry season, crop residues was the first livestock feed source followed by natural pasture in all altitudes. However, during wet season, natural pasture was the first livestock feed source followed by crop resides in all altitudes. In terms of dry matter [DM] crop residues contributed the highest proportion [66.7%] of the total feed sources. The DM obtained from crop residues significantly varied [P&lt; 0.05] among the altitudes. The total annual estimated available feed supply to maintain the livestock in the area satisfied only 79.4%. The conservation of feed resources in the form of hay in high, mid and low altitudes was 38.5, 80, and 22.5%, respectively. But, none of the respondents used silage in the study area due to lack of knowledge how to make it. In the district, a total of 21 herbaceous species were identified [Table 4], from these 57, 24 and 19% were grasses, legumes and other species, respectively. Based on dry matter of biomass, Medicago polymorpha in high and mid altitudes and Eleusine floccifolia in low altitude were the dominant species. Altitude and grazing have effects on grazing land conditions and biomass production. The average dry matter yield of grasses, legumes and total biomass had a significant difference among altitudes in enclosed and communal grazing areas. The average dry matter yield of grasses, legumes, and total biomass were higher in enclosed area than communal grazing areas in all altitudes. There were a significant [P&lt; 0.01] interaction of altitude and grazing on biomass and species composition. There were positive correlation of species composition, grass species composition and basal cover with biomass. Crop residues and natural pastures are the major feed resources in dry and wet seasons, respectively. The total annual dry matter does not meet the total livestock requirement per annum in district. Further research and development work is recommended to alleviate feed shortage through different options such as development of improved forages and alternative means of crop residue utilization and conservation of feed in the form hay and crop residues. Keywords: Altitudinal range; Botanical composition; Crop residues; Dry matter; Feed balance; Grazing land types; Natural pasture;

One-time phosphate fertilizer application to grassland columns modifies the soil microbiota and limits its role in ecosystem services

This study evaluated the effect of one-time phosphate fertilization on the soil microbiota, its cycling of phosphorus (P) and grass growth. Soil columns were established in a greenhouse using a P-limited Irish soil (index 1), planted with Lolium perenne and fertilized with 0 (control), 5 (quarter), 10 (half) and 20 (full)kgPha−1 as inorganic phosphate. Only traces of phosphate in soil solution were detected over the 14week experiment, even after phosphate fertilization. Grass dry matter yield between treatments was not significantly different. Full phosphate fertilization significantly reduced the arbuscular mycorrhization (AM) rate, bacterial- and fungal-feeding nematode population, bacterial phoD gene abundance, but increased alkaline and acid phosphatase activities at the time of harvest. Full and half P treatments significantly shifted the bacterial, fungal and AM community structures compared to the control. Furthermore, the control had a significantly higher relative abundance of bacterial genera including Bacillus, Bradyrhizobium, Paenibacillus, Nocardioides and Balneimonas, that have been associated with P mobilization in the past, when compared to the full phosphate treatment. These results suggest that a positive effect of a single phosphate application on plant growth in a soil can be cancelled out by its negative effect on the soil microbiota and their ecosystem services.

Effects of acidification and injection of pasture applied cattle slurry on ammonia losses, N 2 O emissions and crop N uptake

Abstract Surface application of cattle slurry on grassland is characterized by a high risk of ammonia (NH 3 ) losses. Different techniques and measures to lower these emissions are available, but reported abatement efficiencies vary substantially among studies. Therefore, a direct comparison of five different slurry application techniques was conducted in a two year field trial (2012–2013) on perennial grassland in Southern Denmark (sandy soil) and Northern Germany (marsh, clay soil). The techniques included open slot injection of cattle slurry with different distances between double disc injectors (0.166 m injection close, IC; 0.33 m injection wide, IW) and bandspreading of cattle slurry acidified to pH 6.5 (acid low, AL) and 6.0 (acid high, AH) as well as band spreading as reference (BS). For evaluation of N efficiency of slurry treatments, mineral fertilizer equivalents (MFE) were derived by comparison with a mineral N yield response curve. NH 3 emissions were measured with the combination of passive flux sampling and a dynamic chamber method. Nitrous oxide (N 2 O) emissions were determined with a static chamber method at the marsh site. Grass dry matter yield and N yield were determined in all treatments. Ammonia losses were significantly reduced compared to BS treatment by 31, 61, 42 and 79% by IC, IW, AL and AH, respectively. Slurry application techniques had no significant effect on dry matter yield at both study sites. Only treatment AH resulted in higher N uptake among slurry treatments on sandy soil (2012) or clay soil (2013). Except for AH with highest MFE values at Waygaard, MFE values of slurry treatments were higher at sandy soil (53–62%) than at clay soil (39–88%). N 2 O emissions were at a low level in 2012 (0.12–0.38% of N total ) and showed no significant differences among application methods. In 2013, N 2 O emissions were higher (0.07–0.75% of N total ) compared to 2012 and IW resulted in significantly higher emissions than BS. Treatment AH (acidification to pH 6.0) showed lowest NH 3 losses, highest yields while N 2 O emissions were not-significantly increased. Acidification and injection methods proved to reduce NH 3 losses reliably but trade-offs like increased N 2 O emissions from IW and high acid requirement from AH of 4.8 l t −1 slurry have to be taken into consideration.

Feed Resources Gozamen District, East Gojjam Zone, Amhara Region

The study was conducted in Gozamen district of East Gojam Zone of the Amhara region to assess the major feed resources, the grazing land condition, the floristic composition, and biomass yields of herbaceous species to generate baseline information which can be used for future management of grazing land resources and to identify feed constraints in the area. The survey data was collected by interviewing a total of 120 households by random selection of two ruralkebeles from three altitudes (high, mid and low). To assess grazing land condition, the district was stratified into three altitudes (high, mid and low altitudes). From each altitude, communal and enclosed grazing areas were selected randomly. From each altitude 8 composites and 12 composites from enclosed and 12 composites from communal grazing for herbaceous vegetation and 4 transects from each altitude of communal grazing were selected. Thus, a total of 72 quadrats were used for herbaceous and 12 transects for woody species. For the natural pasture condition assessment, analyses of variance (ANOVA) were carried out by the General Linear Model (GLM) procedure of SAS. Mean separation was tested using the least significant difference. The main feed resources to the livestock in all altitudes were natural pasture, crop residues and stubble grazing. During dry season, crop residues was the first livestock feed source followed by natural pasture in all altitudes. However, during wet season, natural pasture was the first livestock feed source followed by crop resides in all altitudes. In terms of dry matter (DM) crop residues contributed the highest proportion (66.7%) of the total feed sources. The DM obtained from crop residues significantly varied (P<0.05) among the altitudes. The total annual estimated available feed supply to maintain the livestock in the area satisfied only 79.4%. The conservation of feed resources in the form of hay in high, mid and low altitudes was 38.5, 80, and 22.5%, respectively. But, none of the respondents used silage in the study area due to lack of knowledge how to make it. In the district, a total of 21 herbaceous species were identified, from these 57, 24 and 19% were grasses, legumes and other species, respectively. Based on dry matter of biomass, Medicago polymorpha in high and mid altitudes and Eleusine floccifolia in low altitude were the dominant species. Altitude and grazing have effects on grazing land conditions and biomass production. The average dry matter yield of grasses, legumes and total biomass had a significant difference among altitudes in enclosed and communal grazing areas. The average dry matter yield of grasses, legumes, and total biomass were higher in enclosed area than communal grazing areas in all altitudes. There were a significant (P<0.01) interaction of altitude and grazing on biomass and species composition. There was positive correlation of species composition, grass species composition and basal cover with biomass. Crop residues and natural pastures are the major feed resources in dry and wet seasons, respectively. The total annual dry matter does not meet the total livestock requirement per annum in district. Further research and development work is recommended to alleviate feed shortage through different options such as development of improved forages and alternative means of crop residue utilization and conservation of feed in the form hay and crop residues.

Potential for Controlled Traffic Farming (CTF) in Grass Silage Production: Agronomics, system design and economics

Grassland silage management is generally ad hoc resulting in soil compaction damage. Literature suggests grass yield reductions of 5 to 74% through compaction (UK mean 13%), while a 2015 study, reported here, comparing grass dry matter (DM) yield between controlled traffic farming (CTF) and normal management (N), found a 13.5% (0.80 t ha−1) increase for CTF. Commercially available grass forage equipment with widths of 3 to 12 m set up for CTF reduced trafficked areas from 80%–90% for N to 40%–13%. Economic analysis based on 13% increase in DM for 2 and 3 cut systems, gave an increased grass value between £38 ha−1 and £98 ha−1. CTF for multi-cut grass silage effectively increases yields by reducing compaction and sward damage.