Herbage Phosphorus Research Articles

Biochar and nitrogen application rates effect on phosphorus removal from a mixed grass sward irrigated with reclaimed wastewater.

This 2-year (2017 and 2018) field study evaluated biochar and nitrogen application rates effect on herbage phosphorus (P) and nitrogen (N) removal from a mixed-grass sward of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] and Kentucky bluegrass (Poa pratensis L.) irrigated with treated wastewater. Treatments used in this study carried out at the Main Station Field Laboratory, Reno, NV were three biochar application rates (0, 8.9, and 17.8Mg/ha), and three N rates (0, 80, and 120kgN/ha) arranged in a 3×3 factorial in a randomized complete block design experiment with four replications of each treatment combination. Responses were considered different P<0.05. There was a linear increased in soil volumetric water content as biochar rate increased from 0 to 17.9Mg/ha. However, biochar application rate did not affect the quantity of biomass produced, forage tissue P and N concentrations, P and N removal or interact with the other experimental variables of N rate and year to influence the response variables. There was, however, an N rate effect (P<0.05) on biomass production and it was greater for the 80 and 120kgN rate (average=8.3Mg DM/ha) relative to the 0kgN/ha rate (6.0MgDM/ha). Further, cumulative P removal for the 80 and 120kgN rate (average=48.9kg/ha) was greater than the 0kgN/ha rate (38.1kg/ha), and cumulative N removal was in the order 120kgN/ha (321.1kg/ha)>80kgN/ha (267.4kg/ha)>0kgN/ha (187.8kg/ha). There was a trend for a biochar×N rate interaction on soil P concentration and it tended to be greater for the combinations 8.9 and 17.8Mg/ha biochar rates and 80 and 120kgN/ha rates compared to the unamended control. Even though our study did not reveal a definitive effect of biochar on the major response parameters (biomass, tissue P and N concentrations) evaluated, the trend for a biochar×N rate interaction on soil P concentration offers hope that biochar-amended soils coupled with appropriate N fertilization will be effective in P retention on agricultural landscapes irrigated with treated wastewater.

Herbage and Seed From Texan Native Perennial Herbaceous Legumes

Native seed mixes for rangeland seeding, prairie restoration, or cultivated pasture can benefit from a greater variety of forbs that more closely reflect the original vegetation of the southern Great Plains. Fifteen native, perennial herbaceous legumes were collected in central Texas and evaluated for herbage production, mineral content, and fiber concentration of established plants in research plots over 2 years. Downy milk-pea ( Galactia volubilis [L.] Britton) was productive, regardless of rainfall, whereas prairie acacia ( Acacia angustissima [Mill.] Kuntze var. hirta [Nutt.] B.L. Rob.) and Illinois bundle-flower ( Desmanthus illinoensis [Michx.] MacMill. Ex. B.L. Rob. & Fernald) out-yielded others in year 3 when rainfall was the greatest. Herbage crude protein averaged approximately 100 g·kg −1 for bush-clovers ( Lespedeza spp.) compared to bundle-flowers ( Desmanthus spp.), which exceeded 200 g·kg −1 ; the latter also was high in herbage phosphorus. Herbage neutral detergent fiber ranged from 300 to more than 500 g·kg −1 , acid detergent fiber ranged from 140 to 360 g·kg −1 , and acid detergent lignin ranged from 36 to 140 g·kg −1 , a wide range from which to select if animal nutrition is a primary criterion. Seed production was evaluated within a subset of 8 entries submitted to periodic herbage removal or left intact throughout the season. Three bundle-flowers yielded the greatest mass and seed number, but were negatively affected by harvest, unlike prairie acacia. Herbage and seed characteristics indicate there are promising perennial herbaceous legumes in the southern Great Plains that can be included in native seed mixes. Las mezclas de semillas nativas para la siembra de pastizales, restauración de praderas o pasturas cultivadas pueden beneficiarse de una gran variedad de hierbas que reflejan más cercanamente la vegetación original de las Grandes Planicies del sur. En la parte central de Texas se colectaron 15 leguminosas herbáceas perennes nativas y se evaluaron en dos años para ver su producción de forraje, contenido mineral y concentraciones de fibra de plantas establecidas en parcelas experimentales. “Downy milk-pea” ( Galactia volubilis [L.] Britton) fue productiva sin importar la precipitación, mientras que “Prairie acacia” ( Acacia angustissima [Mill.] Kuntze var. hirta [Nutt.] B.L. Rob.) e “Illinois bundle-flower” ( Desmanthus illinoensis [Michx.] MacMill. Ex. B.L. Rob. & Fernald) sobrepasaron en rendimiento a las otras especies en el tercer año, cuando se presentó la mayor precipitación. La proteína cruda del forraje promedió aproximadamente 100 g·kg −1 en el “Bush-clovers” ( Lespedeza spp.) en comparación con el “Bundle-flowers” ( Desmanthus spp.) que excedió los 200 g·kg −1 , esta última también fue alta en fósforo. La fibra neutro detergente del forraje varió de 300 a más de 500 g·kg −1 , la fibra ácido detergente de 140 a 360 g·kg −1 , y la lignina ácido detergente de 36 a 140 g·kg −1 , un rango amplio del cual seleccionar si la nutrición del animal es el principal criterio. La producción de semilla fue evaluada dentro de un subgrupo de 8 entradas sujetas a remoción periódica del forraje o con la hoja intacta a lo largo de la estación. Tres “Bundle-flowers” rindieron la mayor masa y número de semillas, pero fueron negativamente afectadas por la cosecha de forraje, menos la “Prairie acacia.” Las características del forraje y la semilla indican que hay leguminosas herbáceas perennes prometedoras en las Grandes Planicies de sur que pueden ser incluidas en las mezclas de semillas nativas.

Herbage and Seed From Texan Native Perennial Herbaceous Legumes

Native seed mixes for rangeland seeding, prairie restoration, or cultivated pasture can benefit from a greater variety of forbs that more closely reflect the original vegetation of the southern Great Plains. Fifteen native, perennial herbaceous legumes were collected in central Texas and evaluated for herbage production, mineral content, and fiber concentration of established plants in research plots over 2 years. Downy milk-pea (Galactia volubilis [L.] Britton) was productive, regardless of rainfall, whereas prairie acacia (Acacia angustissima [Mill.] Kuntze var. hirta [Nutt.] B.L. Rob.) and Illinois bundle-flower (Desmanthus illinoensis [Michx.] MacMill. Ex. B.L. Rob. Fernald) out-yielded others in year 3 when rainfall was the greatest. Herbage crude protein averaged approximately 100 g kg-1 for bush-clovers (Lespedeza spp.) compared to bundle-flowers (Desmanthus spp.), which exceeded 200 g kg-1; the latter also was high in herbage phosphorus. Herbage neutral detergent fiber ranged from 300 to more than 500 g kg-1, acid detergent fiber ranged from 140 to 360 g kg-1, and acid detergent lignin ranged from 36 to 140 g kg-1, a wide range from which to select if animal nutrition is a primary criterion. Seed production was evaluated within a subset of 8 entries submitted to periodic herbage removal or left intact throughout the season. Three bundle-flowers yielded the greatest mass and seed number, but were negatively affected by harvest, unlike prairie acacia. Herbage and seed characteristics indicate there are promising perennial herbaceous legumes in the southern Great Plains that can be included in native seed mixes.

Seasonal herbage production from two range types in southern Mozambique

Estimating ideal stocking rates in southern Mozambique based on range productivity is difficult since forage and foggage production of range types receiving different amounts of rainfall have not been quantified to date. Exclosures were constructed in upland and alluvial range types in southern Mozambique and forage yields were measured over 6 years on sub-plots harvested when grasses reached 25% flower, in May or in October. Herbage yields were highly correlated (>0.90) to seasonal rainfall that varied from 498 to 837mm yr−1. Upland range produced an average 2.6Mg herbage DMha−1 yr−1 while alluvial soils averaged 6.4MgDMha−1 yr−1. The 25% flower subplots out-yielded (P>0.05) the other harvests only in the first season while the May harvests had greater herbage production (P<0.05) in all other seasons except the high rainfall year. Herbage phosphorus concentration was 13% greater in the alluvial range sites while acid detergent fibre and lignin concentrations were 21.7% and 47.9% higher, respectively, in the May harvests compared to the 25% flower treatments. Average nitrogen values were 35% lower in the May harvests than in the 25% flower harvests but did not decrease further in the October foggage. Harvest regime did not affect (P>0.10) the principal species' relative contribution to herbage from season one to season six. Urochloa mosambicensis decreased in the upland range over the trial, perhaps as a result of successive poor-rainfall seasons.

Phosphorus in herbage grasses - prospects of reducing fertiliser phosphate requirements

Previously published results show that herbage grasses vary in the severity with which they compete with white clover (Trifolium repens) for soil phosphorus. It is argued that grasses such as 'Grasslands Matua' prairie grass (Bromus willdenowio with lower herbage phosphorus concentrations than ryegrass, will maintain better productivity and clover contents in the sward as phosphate fertiliser rates are reduced, than a comparable ryegrass sward. Apart from prairie grass, there seems to be little variation in herbage phosphorus levels in current 'Grasslands' forage grasses and screening for reduced levels is advocated. Keywords Bromus willdenowii, competition, cultivars, grasses, herbage, Lolium perenne phosphate, phosphorus, superphosphate.

Some long-term effects of slurry on grassland

SummaryA field experiment is described in which three rates of pig and cow slurry were applied to a ryegrass sward over a period of 16 years. The experiment included control plots and plots receiving fertilizer supplying 200 kg N, 32 kg P and 160 kg K/ha per year.The slurry nutrient concentrations were similar to published values. Pig slurry was more variable than cow slurry and both varied significantly from year to year. Slurry was applied at 50, 100 or 200 m3/ha per year, with each rate divided into three equal applications.Even the highest slurry application rate did not depress herbage yield, which showed a typical response curve to the amount of soluble nitrogen applied. The ammoniumnitrogen content of slurry (61% on average) gave an adequate measure of its effect on herbage yield when it was applied three times per year in spring and summer.Recovery of phosphorus in the herbage averaged 30% from pig slurry, 40% from cow slurry and 66% from-fertilizer. Pig slurry supplied more phosphorus than did cow slurry, and herbage phosphorus content was significantly correlated with the amount applied. Much of the slurry phosphorus may have been organically bound and not available to plants in the short term.Recovery of potassium from pig slurry and fertilizer was nearly 90% and from cow slurry about 70%. Cow slurry supplied potassium in excess of crop requirements so that it accumulated in the soil under the largest dressing. Soil phosphorus reserves declined under the smallest dressing of cow slurry but were maintained at higher application rates. The pig slurry produced a marked accumulation of phosphorus under the largest dressing. The substantial accumulations of phosphorus and potassium from pig and cow slurry respectively gave marked penetration of the soil below 10 cm depth only at the highest application rate. The data suggest that at rates typical of farm practice significant losses of phosphorus and potassium from the rooting zone would be unlikely to occur.The main invading plant species were Agrostis stolonifera L. and Poa spp. Small slurry dressings produced a similar botanical composition to that of plots given fertilizer. Increasing slurry application rates decreased the proportion of L. perenne and increased that of A. stolonifera but only under the largest dressing did L. perenne fall to a small proportion of the sward and A. stolonifera become very dominant. L. perenne made maximum contribution to herbage dry-matter yield early in the season while the proportion of A. stolonifera increased as the season progressed.Under these conditions even extremely large slurry dressings did not depress herbage yield and may not necessarily have reduced herbage quality despite marked changes in sward botanical composition.

Improved pasture response to nitrogen applied in winter after application of urea in autumn

Abstract Nitrogen fertiliser was applied as urea in autumn (2 April 1983) and late winter (14 July 1983) to a predominantly ryegrass-white clover pasture on a Manawatu dairy farm. Responses in terms of herbage production, botanical composition, and certain other sward characteristics were measured on 22 August. Residual responses from the autumn application were small and were not statistically significant. Spring responses were significant for herbage mass, tiller weight, sward leaf area index, herbage phosphorus (% P) and total P yield (kg P/ha), herbage dry matter content (% DM), and apparent stubble yield (kg DM/ha). There was a significant, positive interaction between autumn and late winter applications of urea in that herbage mass response to 30 kg N/ha in winter was 7, 12, and 19 kg DM/kg N for plots receiving 0, 30, and 60 kg N/ha in autumn respectively. Possible reasons for this interaction are briefly discussed.

The effect of fertilizer nitrogen, phosphorus and potassium on the calcium, magnesium and phosphorus status of pasture cut for silage

SUMMARYPhysiological problems in some Fife dairy herds were thought to be associated with mineral imbalance in grass cut for silage. Consequently trials at two sites were conducted to study the effects of three levels of nitrogen and phosphorus and two levels of potassium on yield and composition of pasture cut for silage.Nitrogen increased yield of herbage and reduced its clover content whereas phosphorus and potassium had little effect on yield or clover content. Herbage clover content and calcium concentration declined over the period of the experiment. Mean concentrations of calcium, magnesium and phosphorus were 5·8, 1·7 and 3·4 g/kg respectively. Concentrations of these minerals varied more with time of cutting and with season than with level of applied phosphorus and potassium.Nitrogen tended to reduce calcium concentration in mixed herbage and to increase magnesium concentration in the grass component; it did not affect herbage phosphorus concentrations, but narrowed the calcium-phosphorus ratio in the second cuts. Applied phosphorus increased herbage phosphorus concentration only at the site with the lower soil phosphorus status. Potassium tended to reduce magnesium concentration in clover and, at one site, in mixed herbage; it also tended to reduce herbage phosphorus concentrations in second cuts.Mineral uptake was increased by applied nitrogen. Mean annual uptake of calcium magnesium and phosphorus was 34, 10 and 20 kg/ha respectively.The effects of treatments on concentration and balance of these minerals are discussed in relation to ruminant requirements and maintenance of suitable levels of the minerals in the soil.It is concluded that normal applications of NPK fertilizer are not detrimental to satisfactory mineral balance in pasture.

Nutritive value for lactating dairy cows of the pressed herbage remaining after the partial extraction of leaf juice

A series of six experiments compared the production of lactating dairy cows eating either fresh herbage or the pressed herbage remaining after the partial extraction of juice. Irrigated perennial pasture and irrigated lucerne (Medicago sativa) were used in different experiments. With forage-harvested pasture, extraction removed an average of 42.1 g of protein per kg dry matter (DM) of pasture processed. An average of 85% of the DM of the original fresh pasture was left as pressed pasture. The process lowered the in vitro digestibility, total nitrogen, and cell contents of the herbage, and raised the cell wall constituents. It also reduced herbage phosphorus, potassium, magnesium and sodium, but increased herbage calcium slightly. The milk yield of cows fed an equivalent DM intake of pressed residue was, on average, 6% lower than the milk yield of cows fed fresh pasture. The responses shown by the milk constituents were inconsistent. With lucerne, extraction removed an average of 95.9 g of protein from each kg of fresh herbage and an average of 74% of the lucerne was left as pressed lucerne. This reduced the quality of the pressed residue as determined by in vitro digestibility (5%), Kjeldahl nitrogen (19%) and neutral detergent fibre (27%). However, there was no significant loss of production for cows on the pressed herbage, although there were small differences. It is concluded that lucerne would appear to have the greater potential for a leaf protein extraction industry in the irrigated areas of the Goulburn Valley of Victoria.