Responses of eastern gamagrass [Tripsacum dactyloides (L.) L.] forage quality to nitrogen application and harvest system

Eastern gamagrass is a warm-season perennial with good forage yield and quality, but both may be increased with nitrogen (N) fertilization. The effects of N and harvest management on neutral- and acid-detergent fibers (NDF and ADF), lignin, in vitro dry matter digestibility (IVDMD), and crude protein (CP) were studied. Nitrogen (0, 50, or 100 kg ha^?1) was applied by broadcasting or knife placement, and forage was harvested from 1- or 2-cut systems. Data were obtained during four years of N treatment, and three intervening years with no N treatment. Neutral- and acid-detergent fibers and lignin were usually lower, and IVDMD and CP were generally higher in the 2-cut than in the 1-cut system. Increasing N affected forage quality in minor ways, except for CP. When 100 kg ha^?1 was applied, CP was increased over no N by 0.14 in the 1-cut system and by 0.25 in cut 1 of the 2-cut system.     

Forage quality and yield increments of intensive managed grassland in response to combined sulphur-nitrogen fertilization Dedicated to Prof. em.Dr. Alois Kornher on his 75th birthday.

Abstract

A three-year experiment was carried out at three different sites in northern Germany to investigate the effects of combined sulphur (S, up to 50 kg S ha^?1 year^?1) and nitrogen (N, up to 300 kg N ha^?1 year^?1) fertilization on dry matter (DM) yield and forage quality. There was an interaction effect of site, year, S and N fertilization. The greatest DM yield increment relative to yield at the start of the experiment (1997) with no S and N applied was 10.2 t DM ha^?1 at Ostenfeld (arable grassland). Cattle slurry when applied to provide 50 kg N ha^?1 and 10 kg S ha^?1 did not noticeably increase yield. The S content in forage decreased significantly over the years without S fertilization. At 300 kg N ha^?1 and 0 kg S ha^?1, crude protein (CP) contents achieved 173 g kg^?1 DM and were diluted due to higher DM yields with S fertilization. The true protein content (TP% of CP) differed significantly at 300 kg N ha^?1. TP achieved 93% with 50 and 87% with 0 kg S ha^?1 year^?1, respectively. In conclusion, with N fertilizer intensities in the range of 300 kg N ha^?1, it is necessary to apply 25 kg S ha^?1 to improve forage yield and quality. On the other hand, with N fertilization levels below 300 kg N ha^?1, S fertilization could be omitted.     

FERTILIZER RATE EFFECTS ON FORAGE YIELD STABILITY AND NUTRIENT UPTAKE OF MIDLAND BERMUDAGRASS

Our objectives were to document effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizer rates on forage yields and uptake of N, P, and K by Midland bermudagrass [Cynodon dactylon (L.) Pers.] on a Minco fine, sandy loam in southern Oklahoma. After six years of this long-term experiment, forage yield responses to fertilization were mixed and depended on year. Stability analysis indicated forage yields responded positively to N fertilization during favorable weather conditions but negatively during poor weather conditions. Application of 112 kg N ha^?1 provided the best yield stability and mean annual forage yield among treatments, 11.5 Mg ha^?1, across years. In years with near-average weather conditions, uptake of N, P, and K increased linearly with N application rate. Limited water holding capacity of the soil and high soil P and K may have contributed to the limited yield responses to fertilization in this semi-arid environment.     

Response of texas bluegrass to season of nitrogen fertilization on the Louisiana coastal plain

Texas bluegrass (Poa arachnifera Torr.) has shown potential for use as a cool‐season perennial pasture grass in the southern Great Plains, where it occurs as a natural component of rangeland plant communities, and into the western Coastal Plain. Responsiveness of this grass to nitrogen (N) fertilization appeared to be limited to the spring growing period in initial evaluations in Louisiana. A field plot experiment was conducted to assess forage production and quality responses to season of N fertilization on the Syn‐1 population of Texas bluegrass. Winter forage production responses to 50 kg N ha^‐1 were obtained in the 1997–98 growing season but not in 1998–99 after stands had been depleted by summer drought. Greatest yield increases resulted from spring N application, however, fall plus winter fertilization provided the most uniform distribution of forage through the cool season. Forage fiber fractions, in vitro digestibility, and crude protein were not affected by N fertilization. Both amount and distribution of Texas bluegrass forage, but not forage quality, can be manipulated by time of N fertilization.     

Soil-Applied Nitrogen and Composted Manure Effects on Soybean Hay Quality and Grain Yield

ABSTRACT

Grain yield in many soybean experiments fails to respond to fertilizer nitrogen (N). A few positive responses have been reported when soybean were grown in the southern U.S., when N was applied near flowering and when biosolids were added. In a previous study, low N concentrations of soybean forage in north Texas on a high pH calcareous soil were reported and thus, we suspected a N nutrition problem. Consequently, we initiated this study to determine whether selected preplant N sources broadcast and incorporated into a Houston Black clay (fine, smectitic, thermic Udic Haplusterts) might increase forage N concentration, forage yield, or soybean grain yield. In 2003, N was applied as ammonium nitrate (NH₄NO₃, AN) up to 112 kg N ha^{? 1} and dairy manure compost (DMC) was applied at rates of 4.9, 9.9, 15.0, and 19.9 Mg ha^{? 1}. The DMC contained 5.9, 2.6, and 6.7 g kg^{? 1} of total N, P, and K, respectively; thus DMC added 29 to 116 kg N ha^{? 1}. In 2004, AN was applied at rates of 112 and 224 kg N ha^{? 1} and DMC was applied at 28 and 57 Mg ha^{? 1}; thus, DMC added 168 to 335 kg N ha^{? 1}. In another 2004 test, biosolids, a biosolids/municipal yard waste compost mixture (BYWC), and AN were compared. The biosolids contained 31, 18, and 2.9 g kg^{? 1} total N, P, and K, respectively. The BYWC mixture contained 8.8, 6.1, and 3.4 g kg^{? 1} of total N, P, and K, respectively. Biosolids were applied at 10 Mg ha^{? 1} (310 kg N ha^{? 1}), BYWC was applied at 58 Mg ha^{? 1} (510 kg N ha^{? 1}), and AN up to 224 kg N ha^{? 1}. None of the soil treatments increased soybean grain yield or forage yield although AN slightly increased forage N concentration in 2003.     

Effects of organic solid cattle manure application on nutritive value of winter cereal forages

Nutritive value of winter cereal forages is one of interested subjects of farmers for animal feeding. Field experiments were established in 2007–2008 and 2008–2009 growing seasons in northeast Turkey to investigate the effect of organic solid cattle manure application (0, 10 and 20 Mg ha^?1 yr^?1) on nutritive value of three annual cereals for forage. The winter cereal forages were: wheat (Triticum aestivum L.), oat (Avena sativa L.) and rye (Secela cereale L.). ADF (acid detergent fiber), NDF (neutral detergent fiber) CP (crude protein), nitrogen, phosphorus, potassium, sulfur, calcium, copper, iron, magnesium, manganese, sodium, zinc and boron (N, P, K, S, Ca, Cu, Fe, Mg, Mn, Na, Zn and B) concentrations were researched in this study. Wheat had the highest CP, N, Ca, Cu, Na and Zn concentration, whereas oat had the lowest ADF and NDF and the highest K, Fe and Mn concentrations. The greatest Mg and P concentrations were determined in rye. Organic solid cattle manure applications had no effect on N and CP contents, but it decreased ADF and NDF contents. However, in most cases it positively affected the P, B, Cu, Fe, Mg and Na concentrations, whereas it decreased K, Ca, Mn and Zn concentrations. The results showed that wheat and oat are more nutritive species than rye in terms of animal feeding and the organic solid cattle manure, in some cases increased the nutritive values of wheat, oat and rye under organic agriculture conditions.     

Interactive Effect of Phosphorus and Nitrogen on Leaf Anthocyanins,Tissue Nutrient Concentrations,and Dry‐Matter Yield of Floralta Limpograss during Short Day Length

Abstract

A field trial was conducted during the short‐day period of 2004–2005 at Ona, Fl., to study the factorial effect of nitrogen (67, 90, and 134 kg N ha^?1) and phosphorus (0, 5, 10, 20, and 40 kg P ha^?1) rates on forage dry‐matter yield, quality, nutrient uptake, and leaf pigment concentration of limpograss (Hemarthria altissima). The N and P fertilizers were applied 45 days before each of two harvests. There was no interaction between N and P rates on any of the measured variables. Cool‐season forage yield increased curvilinearly from 137 to 350 kg ha^?1 in winter and 237 to 1389 kg ha^?1 in early spring, whereas crude protein (CP) concentration increased from 145 to 158 g kg^?1, as P was increased from 0 to 40 kg ha^?1, but yield and CP were not affected by N rate. There was a decreasing linear relationship between leaf concentration of anthocyanins and P rate of application such that forage obtained with 0 kg P ha^?1 had 61% more leaf anthocyanins and purple pigmentation than with 40 kg P ha^?1. There was no effect of N on anthocyanins content. It was concluded that increased level of leaf anthocyanins was due to the cumulative stress from cool weather and lower plant‐tissue P levels, which resulted in reduced growth and yield of limpograss. In cool weather, P played a critical role in controlling leaf purple pigmentation and forage yield.     

Nitrogen rate and cultivar effects on nitrogen and nitrate concentration of sweet potato leaf tissue

Abstract

Nitrogen applications to dallisgrass grown on Olivier silt loam, an Aquic Fragiudalf, increased forage yield, forage digestibility, nutrient concentrations and nutrient contents as N rates increased to 896 kg ha^‐1. Expressing yield as a function of N application rate resulted in quadratic prediction equations that accounted for 75 to 98% of the variability in yield during five years. Eighty‐six percent of the maximum yield was obtained during the five years at 448 kg of N ha^‐1. Plant concentrations of N, Ca and Mg were increased more than concentrations of the other macronutrients as N rates increased. Plant contents of N, Ca and Mg in the forage increased 4.0, 3.2 and 3.5‐fold as N rates increased to 448 kg ha^‐1, while that of P, K and S increased 2.5 to 2.8‐fold. Residual N accumulations in the soil profile were apparent at the 896 kg ha^‐1 rate at the end of the growing seasons but were not detected the following March, indicating N losses by leaching and/or denitrification occurred at that N rate. Phosphorus applications increased forage P concentrations but did not increase forage yield nor available P levels in the surface 15 cm of soil. Maximum yields were obtained at forage P concentrations and Bray No. 2 soil P levels as low as 2.0 g kg^‐1 and 17 mg kg^‐1, respectively.     

Response of bermudagrass selections from the Appalachian region to N and P fertilization

Abstract

A greenhouse experiment was conducted to evaluate the influence of N and P fertilization on the yield and forage quality of six cold tolerant bermudagrass (Cynodon dactylon L.) selections from the Appalachian region. Midland bermudagrass and limpograss (Hermarthria altissima) were included for comparison purposes. Each grass was treated with a factorial combination of three N rates (112, 224, and 448 kg N.ha^‐1) and four P rates (0, 25, 75, and 225 kg P.ha^‐1) Two bermudagrass selections from the Appalachian region demonstrated greater dry matter production than Midland bermudagrass. Yields of Quicksand common exceeded those of Midland by 60% to 236% over the range of treatments. High yielding selections were not inferior to low yielding selections when mineral concentrations, neutral detergent fiber, acid detergent fiber and acid detergent lignin levels were considered. The results of this investigation suggest that Quicksand common and Selection 13 merit further study to determine their potential for summer forage production in the Appalachian region.     

Phosphorus,potassium, chloride,and fungicide effects on wheat yield and leaf rust severity

Abstract

Plant nutrition and disease suppression are among the most important management tools for producers of hard red winter wheat (Triticum aestivum L.) in the central and southern Great Plains. This study was conducted to examine the effects of phosphorus (P) (0, 15, and 30 kg ha^?1) and potassium (K) (0, 37, and 74 kg ha^?1) fertilization, foliar fungicide application, and cultivar disease tolerance on wheat yield, yield components, and severity of leaf rust (Puccinia triticina Eriks.). Compared with no P, fertilizing with P increased yield by as much as 60% (>1.3 Mg ha^?1 increase). Yield of cultivars susceptible to leaf rust was nearly 0.6 Mg ha^?1 less without K than with K fertilization. Fungicide application resulted in mean yields of 4.8 Mg ha^?1 for both resistant and susceptible cultivars, however, yield of susceptible cultivars was suppressed more than yield of resistant ones without fungicide. Although P fertilization had a moderately suppressive effect on leaf rust, the increased yield was primarily due to production of about 50% more heads m^?2 apparently from more prolific tillering. Similarly, K fertilization appeared to reduce leaf rust severity and improve yield by increasing kernel weight, but this response may have been related partially to chloride (Cl) in the KCl fertilizer. Correlations suggested that improving dry matter production and N, P, and K uptakes at the boot stage by P and K fertilization can reduce leaf rust severity later in the growing season and increase wheat grain yield. These results indicate that especially P fertilization, but also K fertilization and fungicide application, are important management tools for reducing disease and increasing winter wheat yield.     

Cover Crop Seeding Rate Effects on Forage Yields of Oat and Barley and Underseeded Bromegrass–Alfalfa Mixture

Annual cover crops compete with underseeded perennial forages for light, moisture, and nutrients and may suppress their establishment and growth. Field experiments were established in 2000 and 2001 at Nipawin and in 2002 and 2003 at Melfort in northeastern Saskatchewan to determine the effects of seeding rates of cover crops of oat (19, 38, and 112 kg ha^?1) and barley (31, 62, and 124 kg ha^?1) on forage dry-matter yield (DMY) of the cover crop cut as greenfeed in the seeding year, DMY of the underseeded meadow bromegrass–alfalfa mixture in the following 1 or 2 years after establishment, and forage quality [concentration of crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF)]. In the first establishment year, the no cover crop treatment produced considerably less DMY than the treatments with cover crops. Oat seeded at 112 kg ha^?1 produced greater DMY than when it was seeded at 19 or 38 kg ha^?1 in all four site-years, but DMY differences between the 19 or 38 kg ha^?1 seeding rates were not significant in any site-year. For barley, there was no significant difference in DMY among the three seeding rates in 2000, 2001, and 2002. In 2003, barley seeded at 62 or 124 kg ha^?1 produced greater DMY than when it was seeded at 31 kg ha^?1, but DMYs were not significantly different between the 62 and 124 kg ha^?1 seeding rates. The use of a cover crop did reduce DMY in 2003 of bromegrass–alfalfa mixture underseeded in 2002, but the type of cover crop and its seeding rate did not appear to affect DMY in any site-year. Forage quality in the seeding year was consistently superior in no cover crop treatment compared to that in treatments with cover crops, especially related to CP concentration. There was no consistent trend of forage quality in the cover crop treatments, indicating cover crops and their seeding rates had little effect on forage quality. In conclusion, oat appeared to be more sensitive to seeding rate than barley for forage DMY in the establishment year, but in the subsequent 1 or 2 years after establishment there was little effect of cover crop type and its seeding rate on DMY of bromegrass–alfalfa mixture, although DMY was considerably greater in the no cover treatment than that in treatments with cover crops in 1 site-year.     

EFFECT OF NITROGEN SOURCES AND RATES ON YIELD AND QUALITY OF SILAGE CORN

The objective of this study was to determine the effect of nitrogen (N) application source and rate on silage corn (Zea mays L.). Urea, ammonium nitrate, and ammonium sulfate were compared at 50, 100, 150, and 200 kg N ha^?1. The application of ammonium sulfate produced the highest plant height, leaf area index (LAI), total yield, and stem, leaf, and ear dry matter, followed by ammonium nitrate and urea. However, nitrogen sources had no marked effects on the content of protein, ash, oil, soluble carbohydrates, acid detergent fiber (ADF) and neutral detergent fiber (NDF). As the rate of nitrogen increased plant height, LAI, total yield, and stem, leaf, tassel, and ear dry matters, and protein, ash and oil contents increased while soluble carbohydrates, ADF, and NDF contents decreased. Ammonium sulfate was the most effective N source on production and 200 kg N ha^?1 was the most effective N rate on corn yield and quality.     

Effects of controlled-release urea combined with conventional urea on nitrogen uptake,root yield,and quality of Platycodon grandiflorum

Field experiments were conducted with four nitrogen fertilizer treatments to study the effects of controlled-release urea combined with conventional urea on the nitrogen uptake, root yield, and contents of protein, soluble sugar, saponin, zinc (Zn), iron (Fe), magnesium (Mg), and copper (Cu) in Platycodon grandiflorum. Field experiments were conducted with four nitrogen (N) fertilizer treatments: no N fertilization; conventional urea with N rate of 175 kg N ha^?1; conventional urea with N rate of 160 kg N ha^?1; controlled-release urea combined with conventional urea with N rate of 160 kg N ha^?1; controlled-release urea combined with conventional urea with N rate of 135 kg N ha^?1. The results showed that nitrogen application significantly increased the yield of P. grandiflorum compared with the control. Treatment with controlled-release urea combined with conventional urea at 160 kg N ha^?1 provided the highest yield of 7329.58 kg ha^?1. Nitrogen application also increased the contents of soluble sugar, total saponin, protein, Zn, Fe, and Mg but decreased Cu content. Protein, saponin, and Zn contents were significantly higher, but Cu content was lower in P. grandiflorum fertilized with controlled-release urea combined with conventional urea than those fertilized with conventional urea alone. The combination of controlled-release urea with conventional urea at 160 kg N ha^?1 was the optimal treatment under the experimental condition investigated in this study.     

Nitrogen application effects on forage sorghum production and nitrate concentration

Abstract

Forage sorghum (Sorghum bicolor (L.) Moench) is an important annual forage crop but prone to high nitrate concentration which can cause toxicity when fed to cattle (Bos taurus and Bos indicus). Two field experiments were conducted over six site-years across Kansas to determine the optimum nitrogen (N) rate for no-till forage sorghum dry matter (DM) yield and investigate the effect of N fertilization on sorghum forage nitrate content. A quadratic model described the relationship between sorghum DM and N rate across the combined site-years. Maximum DM yield of 6530?kg ha^?1 was produced with N application rate of 100?kg N ha^?1. The economic optimum N rate ranged from 55 to 70?kg N ha^?1 depending on sorghum hay price and N fertilizer costs. Crude protein concentration increased with N fertilizer application but N rates beyond 70?kg N ha^?1 resulted in forage nitrate concentrations greater than safe limit of 3000?mg kg^?1. Nitrogen uptake increased with N fertilizer application but nitrogen use efficiency and N recovery decreased with increasing N fertilizer rates. In conclusion, forage sorghum required 55–70?kg N ha^?1 to produce an economic optimum DM yields with safe nitrate concentration.     

NITROGEN,PHOSPHORUS, AND POTASSIUM NUTRIENT EFFECTS ON GRAIN FILLING AND YIELD OF HIGH-YIELDING SUMMER CORN

A three-site-year field experiment was conducted to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer effects on grain filling dynamics and yield formation of high-yielding summer corn (Zea mays L.) in a wheat (Triticum aestivum L.)-corn double crop cropping system. Application of combined NPK fertilizers resulted in the greatest grain yield, largest grain number and grain weight when compared with the treatments receiving N, NP, or NK. Grain filling rate and duration, grain volume, and grain yield increased with NPK rates; however, doubling the rate of 180 kg N ha^?1, 40 kg P ha^?1, and 75 kg K ha^?1 fertilizer only led to minimal increases in grain filling rate (0.8%), grain filling duration (1.6%), grain volume (1.3%) and grain yield (0.4%). Our results suggested that for the high-yielding summer corn, a combined NPK fertilization is required to enhance grain filling and yield, and that under well-fertilized circumstances, limited increases in both grain filling and sink capacity might be the main factor restricting further yield improvement.     

The effects of pure and undersowing green manures on yields of succeeding spring cereals

Abstract

A field experiment was conducted in 2004–2006 to investigate the effect of green manure treatments on the yield of oats and spring barley. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, and organic matter driven into soil and their effect on cereal yield. The spring barley field had a total of 41.7–62.4 kg N ha^?1 and 1.75–2.81 Mg C ha^?1 added to the soil with straw, weed, and roots, depending on the level of fertilisation; with red clover, and both common and hybrid lucerne undersowing, with barley straw and roots, the values were 3.45–3.96 Mg C ha^?1 and 139.9–184.9 kg N ha^?1. Pure sowings of these three leguminous green manure crops had total applications of 3.37–4.14 Mg C ha^?1 and 219.7–236.8 kg N ha^?1. The mixed and pure sowing of bird's-foot trefoil provided considerably less nitrogen and carbon to the soil with the biomass than with the other leguminous crops. Application of biomass with a high C/N ratio reduced the yield of the succeeding spring cereals. Of the green manures, the most effective were red clover and both common and hybrid lucerne, either as undersowing or as pure sowing. Undersowings with barley significantly increased the N supply for the succeeding crop without yield loss of the main crop compared with the unfertilised variant. Compared with ploughing-in of green manure in autumn, spring ploughing gave a 0.2–0.57 Mg ha^?1 larger grain yield.     

土壤碳氮对多年生能源草、覆盖作物和氮施肥的响应

Cover crop and nitrogen(N) fertilization may maintain soil organic matter under bioenergy perennial grass where removal of aboveground biomass for feedstock to produce cellulosic ethanol can reduce soil quality. We evaluated the effects of cover crops and N fertilization rates on soil organic carbon(C)(SOC), total N(STN), ammonium N(NH_4-N), and nitrate N(NO_3-N) contents at the0–5, 5–15, and 15–30 cm depths under perennial bioenergy grass from 2010 to 2014 in the southeastern USA. Treatments included unbalanced combinations of perennial bioenergy grass, energy cane(Saccharum spontaneum L.) or elephant grass(Pennisetum purpureum Schumach.), cover crop, crimson clover(Trifolium incarnatum L.), and N fertilization rates(0, 100, and 200 kg N ha~(-1)). Cover crop biomass and C and N contents were greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1) than in the treatment of energy cane and elephant grass. The SOC and STN contents at 0–5 and 5–15 cm were 9%–20% greater in the treatments of elephant grass with cover crop and with or without 100 kg N ha~(-1)than in most of the other treatments. The soil NO_3-N content at 0–5 cm was 31%–45% greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1)than in most of the other treatments.The SOC sequestration increased from 0.1 to 1.0 Mg C ha~(-1)year~(-1)and the STN sequestration from 0.03 to 0.11 Mg N ha~(-1)year~(-1)from 2010 to 2014 for various treatments and depths. In contrast, the soil NH_4-N and NO_3-N contents varied among treatments,depths, and years. Soil C and N storages can be enriched and residual NO_3-N content can be reduced by using elephant grass with cover crop and with or without N fertilization at a moderate rate.     

Yard Trimmings as a Source of Nitrogen for Crop Production

Yard trimmings from sources rich in grass clippings have the potential to supply nutrients for crop production. Our objectives were to estimate N availability from yard trimmings and determine their effects on crop production, soil nutrients, and organic matter levels. We conducted a field experiment, comparing three consecutive years of yard trimmings applications (22, 44, or 66 Mg ha^?1 yr^?1 dry weight) with inorganic N (112 kg N ha^?1 yr^?1) and zero-N controls in a silage corn (Zea mays L.) - winter triticale (Triticosecale spp.) rotation. The yard trimmings were screened and ground, and allowed to heat for a short period. They were incorporated each spring before planting corn. We measured crop yield and N uptake, and estimated apparent N recovery (ANR). We measured soil inorganic N two weeks after yard trimmings application and after corn harvest. In a one-year on-farm demonstration, we compared three sources of yard trimmings applied at a single rate. Yard trimmings applied at 44 Mg ha^?1 dry weight provided sufficient available N to replace inorganic N. For silage corn grown with summer irrigation, estimated ANR in the crop was 7% in Year 1, 19% in Year 2, and 18% in Year 3 at the 44 Mg ha^?1 yard trimmings rate, compared with a mean ANR of 65% for the inorganic N treatment. Postharvest soil nitrate residual (0-to 120-cm depth) was similar for the 44 Mg ha^?1 treatment and inorganic N treatment. We observed variation in N availability with year and source of material. Yard trimmings also increased soil test K and organic matter.     

Maturity Effects on Mineral Concentration and Uptake in Annual Ryegrass

ABSTRACT

Annual ryegrass (Lolium multiflorum Lam.) provides livestock feed and captures nutrients from fields receiving manure application. The objective of this study was to determine relationships among maturity and yield, mineral uptake, and mineral concentration. Primary spring growth of ‘Marshall’ ryegrass was harvested every 7 d to 56 d maturity and was fertilized with swine effluent containing 254 and 161 kg nitrogen (N) and 42 and 26 kg phosphorus (P) ha^?1 for two years. Yield increased linearly to a maximum of 13.6 mg ha^?1 after 49 d in 2001 and 8.0 mg ha^?1 after 56 d in 2002. Mineral uptake was highly correlated (r > 0.95) with yield and attained a maximum single harvest of 192 kg N ha^?1 and 32 kg P ha^?1 (mean of two years). Concentration of all minerals except calcium (Ca) declined as ryegrass matured. Low magnesium (Mg) concentration (< 2 g kg^?1 dry matter) increases the risk of hypomagnesemic grass tetany.     

INFLUENCE OF TWENTY-THREE ANNUAL APPLICATIONS OF NITROGEN AND SULFUR FERTILIZERS,AND ONE-TIME LIMING ON DRY MATTER YIELD OF GRASS AND SOME SOIL PROPERTIES ON A DARK GRAY CHERNOZEM SOIL

Most soils in the Prairie Provinces of Canada are deficient in plant-available nitrogen (N), and many soils in the Parkland region also contain insufficient amounts of plant-available sulfur (S) for high crop production. A field experiment with perennial grass stand was conducted to determine the effects of long-term annual N (112 kg N ha^?1), S (11 kg S ha^?1) and potassium (K) (40 kg K ha^?1) fertilization, and one-time lime application on forage dry matter yield (DMY) and soil properties [pH, total organic carbon (TOC) and N (TON), and light fraction organic C (LFOC) and N (LFON)] on a Dark Gray Chernozem (Boralfic Boroll) loam at Canwood in north-central Saskatchewan, Canada. The experiment had surface-broadcast annual treatments of no fertilizer (Nil), N, S, NS, and NSK fertilizers from 1980 to 2002, and one-time lime application in 1992 to bring soil pH to about 7. Application of N or S alone had only a little effect on DMY compared to unfertilized Nil treatment, while application of both NS together substantially increased DMY, and forage yield was further increased when K was also applied (NSK). The DMY following one-time liming was greater in limed plots than in unlimed plots for at least 10 years. Decline of soil pH by fertilization mainly happened in the 0–10 cm depth with N only, and in the 0–5 cm layer with NS treatment, whereas these treatments tended to increase soil pH in layers below 10 cm. One-time surface application of granular lime increased soil pH, mainly in the 0–5 cm layer, and the effect was maintained for at least 9 years. Mass of TOC, TON, LFOC, and LFON in different soil layers increased with combined applications of N and S fertilizers (NS), but the effect was much more pronounced in the 0–7.5 cm soil layer, and also varied with organic fraction. Light organic fractions were more responsive to applied NS than total organic fractions. The findings suggest that application of N and S together was effective in sustaining high forage yield and increasing C and N sequestration in a soil deficient in both N and S.