Optimum Nutrient Concentrations and CND Scores of Mature White Spruce Determined Using a Boundary-Line Approach and Spatial Variation of Tree Growth and Nutrition

ABSTRACT

Standards of optimum nutrition are not readily available for mature trees of the Canadian boreal forest. The objective of this study was to determine foliar nutritional standards for white spruce for all major nutrients [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and manganese (Mn)] using critical values (CVA) and compositional nutrient diagnosis (CND). Trees were sampled at two locations in Ontario and Quebec to cover a gradient of soil fertility levels. A boundary-line approach was used in combination with quadratic regression models to estimate the relationship between growth and foliar-nutrient concentrations or CND scores when free of the effects of interacting environmental factors. White spruce optimum nutrition ranges were computed from significant relationships (P ≤ 0.10) for N, P, K, Ca, and Mn concentrations and for N, P, and K CND scores. Optimum concentrations for first-year needles were 12.3, 1.9, 7.3, 6.5, and 0.39 mg g^?1 for N, P, K Ca, and Mn, respectively, whereas optimum CND scores were 0.17, ?1.65, ?0.40, and ?0.30 for N, P, K, and Ca, respectively. Samples from a broader range of environmental conditions will be required in order to establish standards for all major nutrients and to ascertain toxicity levels of most nutrients.     

矿物养分来源与缺乏影响人体健康与营养的研究进展

Mineral nutrients are fundamentally metals and other inorganic compounds.The life cycle of these mineral nutrients begins in soil,their primary source.Soil provides minerals to plants and through the plants the minerals go to animals and humans;animal products are also the source of mineral nutrients for humans.Plant foods contain almost all of the mineral nutrients established as essential for human nutrition.They provide much of our skeletal structure,e.g.,bones and teeth.They are critical to countless body processes by serving as essential co-factors for a number of enzymes.Humans can not utilize most foods without critical minerals and enzymes responsible for digestion and absorption.Though mineral nutrients are essential nutrients,the body requires them in small,precise amounts.We require them in the form found in crops and they can be classified into three different categories:major,secondary,and micro or trace minerals.This classification is based upon their requirement rather than on their relative importance.Major minerals such as potassium(K)and phosphorus(P)are required in amounts of up to 10 g d~(-1).The daily requirement of secondary and micro minerals ranges from 400 to 1500 mg d~(-1)and 45μg d~(-1)to 11 mg d~(-1),respectively.To protect humans from mineral nutrient deficiencies,the key is to consume a variety of foods in modest quantities,such as different whole grains,low fat dairy,and different meats,vegetables and fruits.For insurance purposes,a supplement containing various mineral nutrients can be taken daily.     

Light intensity selectively influences the distribution and further redistribution of macro- and micronutrients in hydroponically grown wheat (Triticum aestivum L.)

Investigations were focused on light effects on allocation of root-borne macronutrients (calcium, magnesium and potassium) and micronutrients (iron, manganese, zinc and copper) in roots, shoots and harvested grains of wheat (Triticum aestivum L.). Plants were exposed to low (100 μmol photons m^?2 s^?1) or high light (380 μmol photons m^?2 s^?1). High light stimulated both root and shoot growth. While the total contents per plant of some nutrients were markedly higher (calcium and potassium) or lower (copper) under high light, no major differences were observed for other nutrients. The distribution of nutrients and the further redistribution within the shoot were influenced by the light intensity in an element-specific manner. Nutrients were selectively directed to the leaves of the main shoot (low light) or to the tillers (high light). The quality of the harvested grains was also affected by the light intensity.     

Influence of arbuscular mycorrhiza and phosphate rock on uptake of major nutrients by Acacia mangium seedlings on degraded soil

To investigate the effects of arbuscular mycorrhiza (AM) and phosphorus (P) source on the uptake of major nutrients by Acacia mangium seedlings, three P sources were used: (1) Gafsa phosphate rock (GPR), (2) China phosphate rock (CPR), and (3) triple superphosphate (TSP). The plant samples were analyzed at 60, 75, 90, 105, 120, and 135 days after planting (DAP) for their N, P, K, Ca, and Mg contents. The uptake of these nutrients was significantly influenced by AM inoculation. Nutrient use efficiency in the AM-inoculated seedlings was also significantly higher than that in uninoculated seedlings. The effect of P sources on the uptake of these nutrients decreased in the order of TSP>GPR>CPR>control. There was a significant (P<0.05) interaction effect of AM and P source on P and K uptake by A. mangium. The uptake of P and K by mycorrhizal seedlings supplemented with TSP was significantly higher than that provided with other sources of P treatments. As a natural and cheaper P source, GPR might be used in combination with AM for growing A. mangium seedlings on degraded tin tailings.     

Leaf nutrients content of tomato and incidence of insect pests and diseases following two foliar applications

The leaf plays key roles in plant functions. In this study, we evaluated major nutrients (Nitrogen (N), phosphorous (P), and potassium (K)) contents of the leaves of tomato (Solanum lycopersicum) following applications of two foliar nutrients sources. Pest population dynamics as well as disease incidence and severity of the crop were also evaluated. The study was conducted at the Plantation Crops Section of the Kwame Nkrumah University of Science and Technology, Ghana in two consecutive cropping seasons. Two tomato varieties were treated with two foliar nutrients sources viz. Herbagreen and Sidalco liquid fertilizer in a split-plot layout. A conventional (granular) NPK fertilizer and a control (no application) were also evaluated. The foliar applications generally increased leaf N concentration of tomato more than the conventional NPK fertilizer and the control. Sidalco liquid fertilizer significantly (p < 0.05) increased foliar K concentration in the major season while Herbagreen increased K concentration by 108% over the NPK fertilizer in the minor season. However, leaf P concentrations were similar (p > 0.05) among the foliar and soil applications. The foliar applications (p < 0.05) reduced the densities of Bemisia tabaci (Gennadius) than the NPK fertilizer and the control in both seasons of cropping. In the minor season, Herbagreen (p < 0.05) reduced both incidence and severity of late blight. Herbagreen treated plants produced fruit yield comparable to the conventional NPK fertilizer and registered lower disease incidence and severity as well as lower insect pest populations possibly due to its silicon content.     

Nutrient cycling in a Pinus patula plantation in the Mpumalanga Province, South Africa

The accumulation of litter on the forest floor was identified as a potential problem in managed plantations of Pinus patula (Schlechtd. et Cham.) in the Mpumalanga Province of South Africa in the late 1980s. Litter accumulation in pine plantations is regarded as a threat to site productivity as organic acids are released, moisture penetration is altered and nutrients are immobilised within the litter. This study examines the cycling of nutrients in a 42-year-old P. patula stand in which litter has accumulated. Samples of the vegetation, litter and soil components were collected and chemically analysed for total nitrogen (N), phosphorus (P) and the major cations potassium (K⁺), calcium (Ca²⁺) and magnesium (Mg²⁺). Complete nutrient budgets for N and P, and the cation pool sizes were determined. It was evident from these studies that large reserves of N (1442 kg ha⁻¹) and P (103 kg ha⁻¹) are stored in the litter layers, with levels of cations being low. The presence of large nutrient reserves within the litter and the predominance of fine feeder roots distributed within this layer indicated that a tightly closed plant–litter–plant nutrient cycle was in operation for the cycling of N and P. This may not be true for the major cations. Management of the litter should ensure retention of as many nutrients as possible in the system. This could be achieved through controlled burning to reduce nutrient loss through volatilisation; increasing forest floor temperatures by altering the planting density and application of dolomitic lime to replace cations and to alleviate the acidic conditions making the litter more favourable for decomposing organisms.     

Factors that contribute to genetic variation for nutrient efficiency of crop plants

Genetic variation in nutrient efficiency may be attributed to two multifactorial components: (i) genotypes may differ in the efficiency with which the nutrients in the plant are utilized to produce yield (utilization efficiency) and/or (ii) they may differ in their effectiveness in absorbing nutrients from the soil (uptake efficiency). This contribution surveys major aspects of physiological and morphological factors affecting N-and P-efficiency. The potential importance of the various factors is discussed and exemplified mainly by own experimental work.     

Impacts of Acid Rain on Base Cations,Aluminum, and Acidity Development in Highly Weathered Soils of Thailand

The impacts of simulated acid rain on leachability of major plant nutrients, toxic element [aluminum (Al)], and acidity development in highly weathered tropical soils of Thailand were studied. Leaching experiments were conducted on soil columns with acidic solutions of pH 5.0, 4.0, 3.0, 2.0, and with water of pH 7.0 as a control treatment. Leaching losses of base cations from all soils increased with the decrease in pH associated with simulated acid rain (SAR) additions, and were found to be quite high under SAR with pH 2.0. The leaching removal of these cations was lesser at pH 3.0, 4.0, and 5.0 but greater than that in pH 7.0. The leaching of base cation from the soils depended not only on acid rain pH but also on soil properties, especially cation exchange capacity, soil texture, and initial base content. The significant losses of major plant nutrients [such as potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺)] from the plant root zone over extended periods could cause nutrient imbalance and lower soil productivity.     

Comparison between fertilizers and untreated sewage effluent as sources for nutrient recovery by wheat (Triticum aestivum)-soybean (Glycine max) cropping system

Recovery and recycling of plant nutrients from municipal sewage effluent (SE) can reduce consumption of costly chemical fertilizers, besides reducing eutrophication of water bodies. Field experiment was conducted on Vertisol of central India for six years with the objective of quantifying recovery of major plant nutrients by aboveground biomass of wheat-soybean cropping system from untreated SE. Wheat crop was grown with irrigation (groundwater and sewage effluent) and fertilizer treatments; while soybean was grown without any treatments. Recoveries of nitrogen (N), phosphorus P) and potassium (K) by the aboveground biomass were considerably more from SE than from fertilizers and manures. Recovery of nutrients from SE was the highest by wheat grain for N and by soybean straw for P and K. Straw biomass of both the crops recovered about 31% N, 22% P and 69% K from SE, which can be recycled back into agricultural land of groundwater (GW) irrigated as well as rainfed area.     

ESTABLISHING LEAF NUTRIENT NORMS FOR ARECANUT BY BOUNDARY LINE APPROACH

Critical and optimum leaf nutrient standards for arecanut are unknown. As nutrients are becoming yield limiting factors in arecanut, corrective measures require development of leaf nutritional standards. The objective of this paper was to determine optimum concentration and range of all nutrients through boundary line approach. Optimum foliar concentrations for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) were established as 2.70, 0.23, 1.12, 0.61, and 0.20%, respectively, using leaf composition data from 12-year old arecanut plantation. Optima of major nutrient concentrations were nearly identical between boundary line approach and mean of high yielding population. Optimum micronutrient concentrations (mg kg^?1) were estimated at 146 for iron (Fe), 56.5 for manganese (Mn), 2.6 for copper (Cu), 45.8 for zinc (Zn), 39.5 for boron (B), 432 for aluminum (Al) and 63 for sodium (Na). Optimum ranges and ratios of different nutrients were found out from second degree polynomial equations.     

翻耕与压实对坡地土壤溶质迁移过程的影响

采用田间模拟降雨试验方法,研究地表翻耕与压实处理对坡地产流产沙及溶质迁移特征的影响。结果表明：与压实处理比较,翻耕坡地初始产流时间延长近3倍,降雨向土壤水转化率提高10％以上,产沙量增加67％;翻耕处理明显降低溶解态磷（DP）和泥沙浸提态磷（SEP）的流失量,但磷素流失形态（DP与SEP的比值）并未显著变化,始终以颗粒态形式流失为主;翻耕处理显著改变了溴的流失形态,溶解态溴（Br）与泥沙浸提态溴（SBr）流失量比值减少了72％;翻耕处理提高了溴（或硝态氮）的淋失概率,增大污染地下水体的潜在危险。因此,合理配置坡地免耕或翻耕措施,有机结合其他农艺耕作措施,对减少坡地水土及养分流失具有重要实践意义。     

Mineralization and microbial immobilization of N and P in arctic soils in relation to season,temperature and nutrient amendment

In situ summer, winter and annual net N and P mineralization and microbial immobilization of mineralized nutrients were measured in a low-altitude subarctic/alpine dwarf shrub heath and in a high-altitude fellfield. Net mineralization was determined by using the buried-bag technique, which was combined with fumigation–extraction to recover microbial nutrients and estimate microbial nutrient immobilization. The measurements were carried out in unperturbed plots and in plots, which had been subjected to elevated temperature and fertilizer addition for 5 years before the experiment started. During the growing season, the microbes in the unperturbed plots immobilized the major part of the mineralized nutrients, which resulted in low net mineralization. This occurred also during winter, when we assumed that nutrients should be released during microbial die-back. However, we found no evidence for a large microbial winter die-back and the surviving microbial biomass even immobilized extra nutrients.Soil temperature enhancement by ca. 2°C in general increased, or tended to increase, net mineralization. However, there was not necessarily any strong correlation between net mineralization and temperature because temperature-induced increase in gross mineralized nutrients could either lead to nutrient immobilization in the microbes or the nutrients could be released to the soil inorganic pool.Fertilizer additions had no major effect on net nutrient mineralization or nutrient immobilization. However, the ligno-cellulose index, which has been used as a predictor of substrate quality and usually correlates negatively with decomposition rate, also appeared to be a good predictor of gross mineralization, but a poor predictor of net mineralization.     

影响禾谷类作物籽实营养素含量的遗传因素分析

禾谷类作物是最重要的粮食作物,为人类提供了必需的营养物质,淀粉、脂肪、蛋白质、维生素和矿物质作为谷物的主要营养素,其含量是培育健康谷物的关键。为给育种研究中有效提升禾谷类籽实的营养品质及谷物的有效利用提供参考,并为培育更具全面营养的谷物提供理论依据,从饮食源头上为人类健康保驾护航。本文基于近年来相关文献资料的梳理归纳,对几种主要的禾谷类作物小麦、大麦、燕麦、水稻和玉米中的几种主要营养素含量进行比较分析,对影响这些营养物质含量和品质的遗传因素进行分析总结,认为小麦、大麦、燕麦、水稻、玉米等禾谷类籽实所含的各类营养物质有较大差异,不同物种遗传背景的差异是导致不同禾谷类籽实营养物质差异的根本原因,而在进化过程中基因突变的平行性又是导致禾谷类籽实中相同营养元素被同类基因编码调控的直接原因。     

三种黑土中有机碳、氮、磷的形态分布与肥力的关系

土壤腐殖质是土壤的重要组分。土壤的许多属性都直接或间接地与腐殖质的性质有关。我们曾指出^[2]黑土的腐殖物质及其组分与土壤的物理、化学及生物化学有显著的相关性,这表明它们对氮、磷等营养物质的转化、供应及贮存起着重要的作用。     

Application of QUEFTS Model for Site-Specific Nutrient Management of NPK in Sweet Potato (Ipomoea batatas L. Lam)

Sweet potato productivity in India is either stagnated or lowering down over the past many years. The main reasons for low yield are conventional blanket recommendation of fertilizers, lower nutrient-use efficiency and imbalance in the use of fertilizers. Recommendation of major nutrients, nitrogen, phosphorus, and potassium (NPK), based on quantitative approaches will augment sweet potato production per unit area by increasing the nutrient-use efficiency. The present study calibrated the Quantitative Evaluation of Fertility of Tropical Soils (QUEFTS) model for the estimation of NPK requirements and fertilizers recommendations for different target yields of sweet potato. The QUEFTS basically works on the principle of NPK nutrient interactions and climate-adjusted yield potential of a region. Published data sets from several field experiments related to NPK carried out till date were collected to reflect the environment variability. The results of the present study showed that to produce one ton tuber, 16:6:18 kg N, P, and K, respectively, would be needed with the internal efficiencies of 61:167:57 kg tubers kg^?1 NPK removed. The maximum accumulation and dilution (kg tuber kg^?1 nutrient removed) of N (40, 80), P (96, 272), and K (30, 85) were also derived as standard parameters in QUEFTS for optimum fertilizer recommendation in tropical and subtropical regions of India. The observed yields of sweet potato with different amounts of nutrients were in agreement with the values predicted by the model. Therefore, it is utmost important to have the results of the study validated in major growing environments of India for fertilizer recommendation in sweet potato.     

Effects of Compost on the Chemistry of an Urban Upper Piedmont South Carolina Soil

Composting is an effective method to improve the fertility of degraded soils. However, the potential beneficial effects of composting on the fertility of urban soils have not been reported. This study compared nutrients measured in compost and soil samples collected from a residential urban plot in Clemson, SC. The dominant soil type present was an eroded Cecil sandy loam (fine, kaolinitic, thermic, Typic Kanhapludults), and the collected samples represented the following treatments: compost, garden, front lawn, backyard lawn, and basement (nonvegetated control). Tissues of leaf detritus were also analyzed to establish the nutrient contribution from leaves to soil. Standard soil tests were conducted to characterize soil macronutrients, macrominerals, and micronutrients, as well as soil parameters such as pH and cation exchange capacity (CEC). Analysis of variance (ANOVA) was used to compare the treatment means for each soil parameter and nutrient measured. In all cases, the different treatments had significantly different levels of nutrients based on Fisher’s least significant difference (LSD) (P < 0.05). Our results show that composting can be a significant source for major soil nutrients and minerals in urban soils. Therefore, utilization of compost and leaf detritus should be beneficial for improving degraded soil in urban environments.     

Sediment‐bound nutrient export from micro‐dam catchments in Northern Ethiopia

The losses in soil nutrients (nitrogen (N), available phosphorus (P_av), organic carbon (OC), potassium (K), calcium (Ca) and magnesium (Mg)) in the catchment and the storage in the reservoir as a result of sediment delivery were assessed in 13 catchments/reservoirs in Tigray, Northern Ethiopia. This specifically dealt with factors controlling the losses, the fertility status of the deposited sediment, the nutrient export (NE) rates and associated costs. Enrichment ratio (ER) values >1 were observed for the plant nutrients and the finer soil fractions. The high ER is associated with the preferential transport of nutrients bound to finer soil fractions and the parent material dissolution and its transport via runoff. However, the fertility status of the deposited sediment is not sufficient by itself to support a sustainable crop growth and hence external addition is necessary, mainly for N and P_av fertilizer. Generally, rates of NE were high. The high OC export on the other hand dictates the potential of reservoir sediments for OC sequestration. The cost price of loss of only N and P_av, eroded from the catchment slopes, was estimated at €34·2 million (Euros) in March 2006 for the Tigray. Pity enough, policy makers and beneficiaries do not realize the magnitude of the problem, which forms a major threat for the crop production in the country. Therefore, it is important not only to make the public aware of the problem but also of implementing integrated soil fertility management practices. Copyright © 2007 John Wiley & Sons, Ltd.     

Evaluation of soil health in organic vs. conventional farming of basmati rice in North India

Conventional agricultural practices that use excessive chemical fertilizers and pesticides come at a great price with respect to soil health, a key component to achieve agricultural sustainability. Organic farming could serve as an alternative agricultural system and solve the problems associated with the usage of agro‐chemicals by sustainable use of soil resources. A study was carried out to evaluate the impact of organic vs . conventional cultivations of basmati rice on soil health during Kharif (rainy) season of 2011 at Kaithal district of Haryana, India, under farmers' participatory mode. Long‐term application of organic residues in certified organic farms was found to improve physical, chemical, and biological indicators of soil health. Greater organic matter buildup as indicated by higher soil organic carbon content in organic fields was critical to increase soil aggregate stability by increasing water holding capacity and reducing bulk density. Proper supplementation of nutrients (both major and micro nutrients) through organic residue addition favored biologically available nutrients in organic systems. Further, the prevalence of organic substrates stimulated soil microorganisms to produce enzymes responsible for the conversion of unavailable nutrients to plant available forms. Most importantly, a closer look at the relationship between physicochemical and biological indicators of soil health evidenced the significance of organic matter to enzyme activities suggesting enhanced nutrient cycling in systems receiving organic amendments. Enzyme activities were very sensitive to short‐term (one growing season) effects of organic vs . conventional nutrient management. Soil chemical indicators (organic matter and nutrient contents) were also changed in the short‐term, but the response was secondary to the biochemical indicators. Taken together, this study indicates that organic farming practices foster biotic and abiotic interactions in the soil which may facilitate in moving towards a sustainable food future.     

上海郊区四种不同类型果园土壤养分特征研究

以上海郊区规模化果园为研究对象,采用土壤养分状况系统研究法(ASI法)对葡萄、桃、柑橘和梨四种类型果园的土壤养分特征进行研究,以期为规模化果园养分的科学管理与高效施肥提供参考。结果表明葡萄园土壤中有效态氮、磷、钾含量普遍高于其他三种果园,而柑橘园土壤主要养分含量则普遍较低;中微量元素方面则不同类型果园之间各具优势;土壤pH方面则葡萄园和桃园呈中性,柑橘园呈弱碱性,而梨园呈弱酸性。总的来说,上海郊区四种不同类型果园中土壤养分特征存在较大差异。根据ASI法养分分级标准,目前上海郊区各类果园中土壤养分处于较为充足的状态,某些土壤养分含量如有效磷处于过量状态,果园的养分管理应根据土壤营养状态做出适当调整,进行按需施肥,从而实现规模化果园的清洁高效生产。     

Dual Inoculation of Arbuscular Mycorrhizal and Phosphate Solubilizing Fungi Contributes in Sustainable Maintenance of Plant Health in Fly Ash Ponds

Fly ash is one of the residues produced during combustion of coal, and its disposal is a major environmental concern throughout coal-based power-generated counties. Deficiencies of essential nutrients, low soil microbial activity, and high-soluble salt concentrations of trace elements are some of the concerns for reclamation of fly ash ponds. The effect of fly-ash-adapted arbuscular mycorrhizal (AM) fungi and phosphate solubilizing fungus Aspergillus tubingensis was studied on the growth, nutrient, and metal uptake of bamboo (Dendrocalamus strictus) plants grown in fly ash. Co-inoculation of these fungi significantly increased the P (150%), K (67%), Ca (106%), and Mg (180%) in shoot tissues compared control plants. The Al and Fe content were significantly reduced (50% and 60%, respectively) due to the presence of AM fungi and A. tubingensis. The physicochemical and biochemical properties of fly ash were improved compared to those of individual inoculation and control. The results showed that combination of AM fungi and A. tubingensis elicited a synergetic effect by increasing plant growth and uptake of nutrients with reducing metal translocation.