An extended nitrogen,phosphorus, and potassium model for tall fescue

Abstract

Dry matter yields and plant nutrient uptake of forage grasses are influenced by levels of applied nitrogen (N), phosphorus (P), and potassium (K). Response to one element generally depends on levels of the other two. In this article, a mathematical model is presented which includes the major elements, N, P, and K as inputs. It consists of triple logistic equations with a total of thirteen parameters. The model is evaluated for Kentucky 31 (KY 31) and Kenwell tall fescue (Festuca arundinacea Schreb.) grown at Watkinsville, GA on Cecil sandy loam (clayey, kaolinitic, thermic, Typic Hapludult). Procedures are described for parameter estimation. The model provides high correlation between yields and plant uptake of N, P, and K with applied N, P, and K for both cultivars of tall fescue, as demonstrated in response graphs and scatter diagrams. Intercept and N response coefficients from this study agree closely with those from previous work. Data from this study support the hyperbolic relationship between dry matter yield and plant N uptake predicted by the model. The model is mathematically well‐behaved and is relatively easy to use in practice.     

Growth and magnesium uptake of tall fescue lines at high and low potassium levels 1

Five tall fescue (Festuca arundinacea Schreb.) clonal lines with diverse root and xylem diameters were grown in nutrient solutions with magnesium (Mg) concentrations of 42, 125 and 250 μM and potassium K concentrations of 133 and 333 μM. Leaf Mg concentrations increased with increasing Mg rates at both low and high K concentrations. The tall fescue line with the largest root and xylem diameters had low leaf Mg concentrations, indicating a possible increased Mg tetany potential when consumed by cattle. The response of the K/(Mg+Ca) ratio in the plant, an indicator of tetany potential, to varying solution Mg at low and high K was determined for each of the five lines. No Mg effects or interactions were significant. Line, K, and line x K effects were all significant for the K/(Mg+Ca) ratios. The line with the largest root and xylem diameters had the highest tetany potential (highest cation ratio). Higher solution K gave higher K/(Mg+Ca) ratios.     

Response of cauliflower to phosphate fertilizer placement and soil test phosphorus calibration on a Karrakatta sand

Abstract

The effect of placement (broadcast versus banded) and level of phosphorus (P) applied as superphosphate at 0 to 450 kg P/ha was measured using the yields of cauliflower (Brassica oleracea var botrytis) on newly cleared Karrakatta sands of low natural P fertility. While there was a significant (P<0.01) yield response to level of P, there was no significant response to fertilizer placement. Phosphorus recovery efficiency by curds (P uptake curds/P applied both in kg/ha) decreased from 0.35 at 20 to 0.09 at 320 kg applied P/ha. Phosphorus recovery efficiency by whole plants decreased from 0.58 at 20 kg P/ha to 0.18 at the highest level. Bicarbonate‐soluble P extracted from the top 15 cm of soil was determined on residual P sites from experiments over two years where P was applied from 0 to 450 kg P/ha. These soil test values were related to yield. The critical soil test values required for 95 and 99% of maximum yield were 40 and 55 (μg/g, respectively. The level of freshly‐applied P required for either 95 or 99% of maximum yield varied from 108 to 175 kg P/ha, respectively at <5 μg/g soil test P to 0 at the critical values. Phosphorus in the youngest expanded leaf at buttoning required for 95 and 99% of maximum yield was 0.46±0.02 and 0.47±0.02%, respectively.     

Response of tall fescue to composted sewage sludge used as a soil amendment

A pot experiment was conducted in the greenhouse to investigate the effects of composted sewage sludge as a soil amendment on growth and mineral composition of ‘Mustang’ tall fescue (Festuca arundinacea Schreb.). Three desert soils (loamy sand, sandy loam, clay) were amended with two different composted sewage sludges (city and county) at rates of 0, 7.5, 15, 30 and 60% by volume. Tall fescue was grown in the amended soils for four months. Growth rates, measured as harvested clippings, increased with sludge loading rate and also with clay content of the soil. Higher growth rates were maintained with the city as compared to the county sludge, although for both sources, growth declined for most treatments after nine weeks. Turf color ratings and percent N in the tissue increased with sludge loading rate and were highly correlated. Tissue analysis indicated a varied response between soil types.     

不同土壤肥力水平下元白菜施氮、磷、钾和锌的效应

对不同土壤肥力水平下元白菜施氮、磷、钾和锌肥的效应研究表明,不同土壤肥力水平下,元白菜施氮、磷、钾和锌均能显著增加产量,分别增产12.0%~35.8%(平均24.5%)、5.3%~14.1%(平均9.7%)、11.2%~15.3%(平均12.9%)和7.5%~11.3%(平均9.1%)。在较高、中等和较低土壤肥力水平下,元白菜经济最佳施氮(N)量分别为310.5、326.1~336.6和378.9 kg/hm2,适宜磷(P2O5)用量依次为60、60~90和90~120 kg/hm2。不同土壤肥力水平地块元白菜适宜施氮时,氮肥(N)利用率在15%~20%,适宜施磷时磷肥(P2O5)利用率在9.3%~11.0%;元白菜上钾肥利用率随土壤钾素水平的降低而呈增加的趋势,不同土壤肥力地块元白菜施K2O 120 kg/hm2时钾肥(K2O)利用率平均为20.4%。     

不同土壤肥力水平下元白菜施氮、磷、钾和锌的效应

对不同土壤肥力水平下元白菜施氮、磷、钾和锌肥的效应研究表明，不同土壤肥力水平下，元白菜施氮、磷、钾和锌均能显著增加产量，分别增产12．0％～35．8％（平均24．5％）、5．3％-14．1％（平均9．7％）、11．2％．15．3％（平均12．9％）和7．5％～11．3％（平均9．1％）。在较高、中等和较低土壤肥力水平下，元白菜经济最佳施氮（N）量分别为310．5、326．1～336．6和378．9kg／hm^2，适宜磷（P2O5）用量依次为60、60-90和90～120kg/hm^2。不同土壤肥力水平地块元白菜适宜施氮时，氮肥（N）利用率在15％～20％，适宜施磷时磷肥（P2O5）利用率在9．3％～11．0％；元白菜上钾肥利用率随土壤钾素水平的降低而呈增加的趋势，不同土壤肥力地块元白菜施K2O120kg／hm^2时钾肥（K2O）利用率平均为20．4％。     

Response of early corn growth to fertilizer phosphorus rates and placement methods

Previous research showed that applying fertilizer phosphorus (P) to the soil in concentrated subsurface bands increased P availability to crops compared to a surface application. Early growth responses of corn (Zea mays L.) plants were measured after 28 days of growth in pots in a greenhouse for single band, two single bands, injection, and surface fertilizer P placement methods. Fertilizer P was applied at the rates of 0, 12, and 24 mg P/kg soil for each method for three different soils. Shoot dry matter weight and nitrogen (N) and P uptake increased for all placement methods regardless of initial soil test P level. However, growth parameters were greater for the banded and injection methods. Response parameters were minimally influenced by the surface P application, but some fertilizer P from the surface application leached through small desiccation cracks after daily additions of water. This probably increased P availability slightly. Shoot dry matter production efficiency and shoot N/P ratio were higher for the surface P placement method and for the unfertilized P treatments. Overall growth responses to fertilizer P rates were less effective in soils with higher initial soil test P levels.     

Changes of weed infestation under long-term effect of different soil pH levels and amount of phosphorus:potassium

ABSTRACT

The aim of the present study was to investigate changes of weed species density as a result of long-term (1976–2005) exposure to different soil pH levels, and P₂O₅:K₂O amount in soil created by initial and subsequent periodical liming, and fertilization. As a result of liming during the period 1976–2005, average soil pH levels at the start of the sixth crop rotation (2001–2005) ranged from 4.1 (unlimed) to 6.6. And in each pH plot were four sub-plots with a different amount of mobile phosphorus:potassium. In acid soil (pH 4.1), in spring oilseed rape and in spring barley crops, the dominant weed Spergula arvensis density decreased significantly at a pH of 5.1 or higher. With increasing amount of P₂O₅:K₂O in soil, the abundance of S. arvensis in spring rape and spring barley crops was reduced at all soil pH levels. At pH 5.1, Chenopodium album and Tripleurospermum perforatum were prominent. Elytrigia repens tended to decrease with increased alkalinity and nutrient amount in soil. With reduction of soil acidity from pH 4.1 to 6.6, the total weed infestation consistently declined in all crops. A low amount of P₂O₅:K₂O in soil caused the decline in the abundance of S. arvensis, E. repens and increase in C. album and T. perforatum.     

Effects of soil acidity and phosphorus on the yield and chemical composition of tall fescue

Abstract

Tall fescue (Festuca arundinacea) is assuming increasing importance as a pasture species in South Africa. Many of the soils on which fescue is grown are inherently high in exchangeable Al and are characterized by high P‐immobilization capacities. The responses of fescue to dolomitic lime and P were examined in a factorial field trial on a red clay (Kandiustalfic Eustrustox) having a pH(KCl) and acid saturation [100(Al+H)/(Al+H+Ca+Mg+K)] in the unlimed state of 4.1 and 48%, respectively. A significant, though very limited, dry‐matter yield response to lime was evident (yields in the absence of lime were approximately 80% of the yields obtained at high lime levels). This pattern in the response to lime remained consistent over the three seasons of experimentation, despite soil acidity levels being substantially increased through the periodic use of ammonium sulphate as the N source in the trial. A significant response to P was evident at the first harvest after establishment; thereafter, P treatments had no effect on yield. The lime and P response data obtained in this investigation indicate that tall fescue is much more tolerant of soil acidity and has substantially lower soil P requirements than other important crop and pasture species in this country, such as maize (Zea mays) and Italian ryegrass (Lolium multiflorum). Lime significantly increased herbage Mg levels yet, in general, did not influence Ca levels in the herbage. Concentrations of Mg in the herbage exceeded Ca concentrations at all lime rates. Luxury uptake of K resulted in the K/(Ca+Mg) equivalents ratio in the herbage frequently exceeding the tetany hazard threshold of 2.2.     

Quantitative effects of soil depth and soil and fertilizer nitrogen on nitrogen uptake by tall fescue and switchgrass

Abstract

In semi‐arid regions, soil depth influences soil N uptake, but not ferilizer N uptake. How soil depth interacts with soil and fertilzer N to influence N uptake in humid regions is not known. The objective was to determine the relative importance of soil depth and soil and fertilizer N uptake, by forage grasses. Tall fescue (Festuca arundinacea Schreb.) and switchgrass (Panicum virgatum L.) were grown on soils of varying depths. Nitrogen rates are 0, 90, and 180 kgN/ha of ¹⁵N depleted (NH₄)SO₄ applied in a split application on fescue and in one aplication to switchgrass. Total N and fertilizer N uptake, were regressed against fertilizer N, variables related to soil depth (waterholding capacity (WC), water use (WU), water loss (WL), and total soil N (SN). Soil variables explained 28% of the accoutable variation in total N uptake by first cut fescue but only 10% by second cut fescue. Soil variables explained 11% of the accountable variation in fertilizer N uptake by first cut fescue and none by the seoond. Soil variables explained 40% of the accountable variation in the total N uptake, by switchgrass, but only 10% of the variation in the fertilizer N uptake. Only where soil depth was less than 90 cm did it have a significant effect on the fertilizer N uptake by first cut fescue. Soil depth had no significant effect on the uptake, of fertilizer N by second cut fescue or switchgrass.     

氮磷钾肥对高羊茅生长及抗寒性的影响

利用盆栽试验研究了氮磷钾肥对冷季型草坪草高羊茅生长、叶绿素含量及抗寒性的影响。结果表明,NPK配合施用能有效促进草坪草生长、叶绿素合成及提高抗寒性。NPK处理的叶片数、叶长及株高分别是不施氮处理的1.23、1.73和1.68倍,是不施磷处理的1.96、2.25和2.04倍。播种后100.d,NPK处理SPAD值分别比PK和NK处理高出2.53和3.14倍;越冬期NPK处理的脯氨酸(Pro)、丙二醛(MDA)和电解质渗透率(EL)分别是PK处理的313.6%、36.4%和13.4%,是NK处理的104.2%、14.0%和11.6%。试验结果还表明,磷肥对草坪草生长影响最大,氮肥次之,氮磷肥缺乏均降低草坪草抗寒性;钾肥施用与否对草坪草生长及抗寒性影响不大。说明氮磷钾肥合理施用能有效改善越冬期草坪质量。     

Relationships between relative crop yields,soil test phosphorus levels,and fertilizer requirements for phosphorus

Abstract

More uniformity in methods of deriving fertilizer P recommendations from crop response data should improve accuracy and precision of fertilization rates. Experimental data that relate crop yields to soil test levels and describe the effect of fertilizer P on soil test levels provide the basis for determining fertilization rates for specific crop‐soil situations. A modification of the Mitscherlich equation was used in derivation of a new equation for calculating fertilizer P requirements as a function soil test levels of P. The equation was applied to response data for 4 crops.

Response curves and fertilizer requirements as calculated for corn, soybeans, alfalfa, and clover‐grass indicated that soybeans yielded relatively more than the other three crops at low soil test levels of P. Corn and alfalfa required higher soil test levels to reach 95% maximum yield and required higher rates of fertilizer P when initial test levels were low.     

Crop and soil response to subsoil loosening, deep incorporation of phosphorus and potassium fertilizer and subsequent soil management on a range of soil types.: Part 1: Response of arable crops

Abstract. Between 1978 and 1985 16 experiments tested crop response to subsoil loosening by either the Wye Double Digger or a winged subsoiler. Additionally, response to incorporation of 350 kg ha of P₂O₅and K₂O into the subsoil was tested. Soil types were mainly well-drained light-and medium-textured soils in arable rotations. Subsoil loosening increased the yield of spring-sown crops on sandy soils in years of moderate to severe drought. Response was associated with deeper rooting and improved water extraction from the subsoil. No yield increases were recorded with autumn-sown crops which were largely grown on the medium and heavy textured soils. There was a trend towards yield reductions on deep silty soils in wetter years. At one site only did the response to phosphorus and potassium fertilizer incorporated into the subsoil exceed that of fertilizer applied to the topsoil.     

有机肥料氮、磷、钾的化学分析方法

介绍了用化学分析方法测定有机肥料氮、磷、钾的含量，即样品经硫酸一过氧化氢消化后，制备待测溶液，分取待测溶液用NC-2型快速定氮仪测定氮，用磷钼酸喹啉重量法测定磷，用四苯硼酸钾重量法测定钾，不须使用分光光度计和火焰光度计，适宜一般复混肥料厂采用，对含氮、磷、钾分别达0．1％以上的样品均可用本法测定，方法的准确度和精密度能满足生产的要求。     

Response of soil exchangeable and crop potassium concentrations to variable fertilizer and cropping regimes in long-term field experiments on different soil types

Annual potassium (K) balances have been calculated over a 40‐year period for five field experiments located on varying parent materials (from loamy sand to clay) in south and central Sweden. Each experiment consisted of a number of K fertilizer regimes and was divided into two crop rotations, mixed arable/livestock (I) and arable only (II). Annual calculations were based on data for K inputs through manure and fertilizer, and outputs in crop removal. Plots receiving no K fertilizer showed negative K balances which ranged from 30 to 65 kg ha^?1 year^?1 in rotation I, compared with 10–26 kg ha^?1 year^?1 for rotation II. On sandy loam and clay soils, the K yield of nil K plots (rotation I) increased significantly with time during the experimental period indicating increasing release of K from soil minerals, uptake from deeper soil horizons and/or depletion of exchangeable soil K (K_ex). Significant depletion of K_ex in the topsoil was only found in the loamy sand indicating a K supply from internal sources in the sandy loam and clay soils. On silty clay and clay soils, a grass/clover ley K concentration of ～2% (dry weight) was maintained during the 40‐year study period on the nil K plots, but on the sandy loam, loam and loamy sand, herbage concentrations were generally less than 2% K.     

Tillage effects on soil properties at different levels of fertilizer application in Punjab, Pakistan

The effects of cropping systems and management practices on soil properties provide essential information for assessing sustainability and environmental impact. Tillage and fertilizer rates were evaluated for their effects on soil bulk density (BD), penetration resistance, soil organic carbon (SOC) concentration and availability of macronutrients on a sandy clay loam (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA; Luvic Yermosol, FAO) in a semi-arid region of Pakistan. Wheat (Triticum aestivum L.) and cotton (Gossypium hirsutum L.) were double-cropped from 1996 to 1998. Tillage treatments were minimum till (MT), conventional till (CT), and deep till (DT). Low, medium and high fertilizer rates were applied to wheat and cotton. BD was affected neither by tillage nor fertilizer rates. Soil penetration resistance was lower for DT than CT and MT. Tillage methods affected soil P concentration but did not affect N and K concentrations. However, fertilizer application significantly increased soil P and K concentrations. Concentrations of N, P, K and SOC were greater in the plough layer than sub-soil. Grain yield of wheat was significantly negatively correlated with penetration resistance and was positively correlated with soil P and K concentrations. Yield of cotton was significantly negatively correlated with soil BD. These data provide an experimental basis to re-evaluate recommendations for fertilizer rates and tillage methods for production of wheat and cotton in Punjab. Further, there is a strong need to establish long-term experiments to study agronomic and environmental effects of tillage methods, fertilizer rates, and cropping systems on productivity and environment quality.     

长期施氮、磷、钾化肥对玉米产量及土壤肥力的影响

以1990年建立的国家褐潮土土壤肥力与肥料效益长期监测基地(北京昌平站)的长期肥料定位试验为研究平台,研究了不同施肥制度对玉米产量和土壤肥力的影响。结果表明,长期均衡地施NPK肥或NPK与有机肥配施,可以显著提高玉米产量和土壤有机质、全氮、全磷、速效氮、速效磷、速效钾等肥力指标,并能提高土壤微量元素的含量;而不均衡施肥(N、NK、NP、PK)导致相应的营养元素的耗竭。相关分析表明,在褐潮土上增施磷肥和有机肥对提高玉米产量具有重要的作用。     

Response of greenhouse cucumber to mineral fertilizers on a high phosphorus and potassium soil

The response of greenhouse cucumber (Cucumis sativus L. cv. Lolita) to nitrogen (N), phosphorus (P) and potassium (K) fertilizers on a soil high in available P and K was studied during 1986. The greenhouses were located in the Beqa Valley, central Lebanon, and their soil chemical properties before planting were: NO₃‐N = 52 ppm, P(NaHCO₃ ext.) = 100 ppm, K (ammonium acetate ext.) = 650 ppm, ECe = 1.6 dS/m, pH = 7.5. Nitrogen at 200 kg/ha, P at 85 kg/ha and K at 150 kg/ha were applied in the following combinations: N, N+K, N+P+K and an unfertilized control. The rates were split into four equal weekly applications starting on the fourth week after transplanting the seedlings to the greenhouse. The treatments were applied through the drip irrigation system of the greenhouses. Fruit yield over the two months of harvest was highest in plants receiving N alone, which yielded 57 ton/ha. Yields of the plots receiving N+K, N+P+K and the control were 55.0, 54.0 and 39.5 ton/ha, respectively. Yield during the first month of harvest was comparable in all fertilized treatments and was substantially higher than the control.     

生姜对氮磷钾缺乏的反应

试验研究了N、P、K缺乏对生姜生长的影响以及缺素症的形态表现。结果表明,N、P、K对生姜生长的影响极大。其中以K处理影响最为严重,至旺盛生长期以后,地上部鲜重持续降低,根茎鲜重却有先增加后降低再增加的特殊现象。其次为N、P处理。在生长后期,N、P、K各处理的根茎鲜重只有CK的40 77%、46 65%和25 25%。     

不同氮磷钾肥对土壤pH和镉有效性的影响

采用土壤培养方法研究了不同氮、磷、钾肥对土壤pH和镉有效性的影响。结果表明,在培养60 d时,所有氮肥处理均降低了土壤pH,增加了Cd的提取量;但高量尿素和氯化铵处理土壤pH降低最多,提取的Cd也最多;硫酸铵提取的Cd较对照增加最小。所有磷肥处理均引起土壤pH小幅降低,但对土壤Cd提取量的影响以普钙稍大。3种钾肥处理均降低了土壤pH,其中氯化钾在0 d时提取的Cd在所有钾肥处理中为最高,其提取能力15 d后逐渐消失,试验结束时所有钾肥处理对Cd提取量均低于对照。本研究进一步表明,在土壤Cd含量处于污染临界值附近或已受Cd污染的土壤上,应避免施用高量的酸性肥料如尿素、氯化铵、普钙,以及其他酸性物料。在常用磷、钾肥中,磷酸二铵和硫酸钾在Cd污染土壤上施用更为适合。