Estimated nitrogen use efficiency,surplus, and partitioning in young apple trees grown in varied organic production systems

A certified organic apple (Malus × domestica Borkh.) orchard was established to study the interaction of ground cover management systems (GMS) and nutrient sources (NS) on nitrogen (N) use efficiency and N surplus in the Southern U.S. for three years. Trees treated with green compost (GC) and wood chips (WC), regardless of the NS, had greater N accumulation and leaf N use efficiency compared to the shredded paper or mow-and-blow treated trees. The WC-treated trees had comparably low N surplus relative to the GC trees that induced more [NO₃⁻] in soil or soil solution in the rooting zone in September in year 3. GC trees had the highest [NO₃⁻] mineralization in the soil during winter. GMS had greater overall effects on the tree response variables than did the NS.     

Response of apple trees to boron fertilization under conditions of low soil boron availability

The aim of the study was to examine the effect of boron (B) fertilization on the vegetative and the reproductive responses of apple (Malus domestica Borkh.) trees grown at low soil B availability. The experiment was carried out in 2005 under a greenhouse on 5-year-old ‘Jonagold’ apple trees/M.9 EMLA planted singly in 50-L containers filled with a sandy loam soil with hot water-soluble B concentration of 0.32 mg kg⁻¹. The trees were fertilized with B as foliar or soil application. Foliar B sprays were applied at the stage of pink bud, beginning of flowering, petal fall, and 10 days after flowering, at a solution concentration of 0.03%. Soil B fertilization was done at the bud break stage at a rate of 2 g per tree (27 mg B kg⁻¹ soil). The trees untreated with B served as the control. The results showed that soil B fertilization improved root development and tree vigor. Leaves of trees supplied with B to the soil had higher B concentration and chlorophyll, net photosynthetic rate, stomatal conductance, and activity of catalase and glutathione reductase than those of the control plants. Boron fertilization, regardless of application mode, increased fruit yield; the efficiency of foliar B sprays was higher than soil B application. Apple fruits of trees fertilized with B to the soil were bigger, more colored, richer in B, and had higher soluble solids concentration, and titratable acidity compared to those of the control trees.     

Evaluating the effectiveness of different strategies for calcium application on the accumulation of calcium in apple (Malus × domestica Borkh. ‘Braeburn’) fruit

Summary

Orchards displaying calcium (Ca) deficiency are a common phenomenon worldwide, despite the presence of sufficient Ca in the soil and the plant. A 3-year trial was conducted between the 2007 – 2008 and 2009 – 2010 growing seasons to evaluate the contributions of soil and foliar Ca applications to Ca concentrations in ‘Braeburn’ apple (Malus × domestica Borkh.) fruit. Ca(NO₃)₂ (Calflo; Yara Africa, Fourways North, South Africa) was applied as six separate foliar sprays until run-off. Applications were made at 1-week intervals between approx. 21 – 70 d after full bloom (DAFB) at 6.75 ml l^–1. Soil applications of Ca (Tropicote^TM; International ASA, Oslo, Norway) at 300 kg ha^–1 were applied at fruit set, or after harvest, according to standard practice. Mineral analysis was conducted to assess the soluble Ca concentrations of whole fruit (without pips and stalks), to quantify the contribution of foliar sprays or soil-applied Ca. Fruit Ca concentrations were maintained at satisfactory levels (4.5 mg Ca 100 g^–1 FW) at harvest by applying a series of six foliar sprays early in the season (for all seasons) during the trial period. Fruit Ca concentrations at 80 DAFB were highest in the treatments with foliar applications of Ca. In 2009 – 2010, Ca concentrations in apple fruit were lowest (8.38 mg 100 g^–1 FW) for soil application of Ca at fruit set. Ca applications to soil after harvest in the previous season, and soil applications shortly after fruit set in the current season, did not significantly increase Ca concentrations in current-season fruit, providing soil Ca levels were above the minimum requirement for apple trees. A possible explanation is that apple trees regulate their uptake of Ca through the roots when soil Ca is available in sufficient quantities. This confirms the importance of active root growth for efficient Ca uptake by apple trees when applying Ca to the soil.     

Screening and selecting novel AM fungi and Azotobacter strain for inoculating apple under soil solarization and chemical disinfestation with mulch practices for sustainable nursery management

The objective of this study is to investigate the response of screening, and selection of novel indigenous AM fungal species and Azotobacter chroococcum strains for inoculating apple under different soil disinfestations and moisture conservation mulch practices for sustainable nursery management. Two local AM fungal species namely, Glomus fasciculatum (Thaxter sensu Gerdemann) and Glomus mosseae (Nicol. & Gerd.), and two strains of A. chroococcum viz., A. chroococcum strain-I (AZ₁) and A. chroococcum strain-II (AZ₂) were inoculated at nursery stage under soil solarization, chemical disinfestation and natural soil conditions at four different mulch materials namely, black plastic mulch (BPM), and organic mulches, i.e. grass mulch (GM); cover crops (CC); green manuring + clean cultivation (Gm + Cc). The comparative performance of the seedlings on the impact of local AM species and A. chroococcum strains on growth characteristics, microbial population, root colonization and leaf nutrient status was evaluated. The inoculation of seedlings to G. fasciculatum and AZ₁ increased all growth characteristics (plant height, stem diameter, leaf area and total root length), microbial consortium of the rhizosphere soil and leaf N, P, K and Zn content in all those plots where soil solarization and black plastic mulching was used followed by chemical disinfestations and natural soil conditions at all other mulch types used. These findings suggested that the soil inoculation of G. fasciculatum and AZ₁ strain to seeds and/or the saplings under soil solarization with black plastic mulch attained a desirable plant height and become ready for grafting which however saved a period of 1 year for nursery management compared to traditional nursery raising practice, and thus, it may be a viable and feasible approach to maintain soil productivity under nutrient limited soils for sustainable apple nursery production under temperate rain-fed conditions.     

微生物菌肥对苹果土壤理化特性及养分吸收的影响

以苹果M9T337矮化砧木幼苗为试材,设置对照(CK)、菌肥120 g+正常施肥(T1)、菌肥240 g+正常施肥(T2)、菌肥360 g+正常施肥(T3)4个处理。研究不同微生物菌肥施用量对苹果营养生长、土壤特性及植株养分吸收的影响,以期为提高苹果品质及可持续发展提供参考依据。结果表明:不同微生物菌肥施用量显著促进了苹果的营养生长和根系活力的提高,总生物量、总根长、根尖数、根表面积和根系活力分别较CK提高了35.2%、11.9%、59.4%、10.7%和65.1%,以T3处理效果最好。不同微生物菌肥施用量能够显著改善土壤的理化性状,增加土壤碱解氮、速效磷、速效钾和有机质含量,与对照相比分别提高了63.1%、47.2%、35.5%、72.3%。同时脲酶、磷酸酶及蔗糖酶的活性相对于CK分别提高了79.5%、50.8%、75.4%。植株全氮、全磷、全钾含量较CK分别提高了66.5%、78.2%和76.8%。表明微生物菌肥能够提高苹果M9T337幼苗的生长,在苹果的生长过程中起积极作用。     

Improvement of soil properties using compost for optimum parsley production in sandy soils

In the warm and wet north Florida climate, growing Italian parsley (Petroselinum crispum [Mill.]) is gaining popularity with small producers as a short duration crop on sandy soil. Application of compost to agricultural land can benefit the low fertile sandy soils in Florida and subsequent crop production, while providing an outlet for recycling municipal solid wastes (MSW) and biosolids. A field study was laid out in a randomized complete block design with four replications to evaluate the effects of compost (75% MSW:25% biosolids) application in comparison to fertilizer, fertilizer + compost (50:50), and control treatments on: (a) parsley fresh weight (FW), (b) soil and plant tissue nutrient concentrations, and (c) soil bulk density and moisture retention in winter and spring seasons. Soil amended with fertilizer or compost + fertilizer doubled parsley FW from 15.02 Mg ha⁻¹ in the non-amended control plot to 30.75 and 32.67 Mg ha⁻¹ in soils that received fertilizer + compost or fertilizer alone, respectively. Significantly higher total soil carbon (C) levels of 2.16% and 1.95% and nitrogen (N) levels of 0.19% and 0.16% were recorded in compost and fertilizer + compost treatments, respectively. Addition of compost reduced soil bulk density significantly to 1.03 Mg m⁻³ and increased soil moisture retention in simulated drier conditions at 1500 kPa to 0.12 m³ m⁻³ in plots that received only compost at the end of winter growing season. Overall, addition of compost resulted in improvement of both physical and chemical properties as well as increased parsley yields.     

Evaluating foliar nitrogen compounds as indicators of nitrogen status in Prunus persica trees

Mobile nitrogen (N) forms may be better N indicators of the N status of trees than total nitrogen (TN) due to their higher sensitivity to increasing N supply. A field experiment was carried out over a 3-year period to compare foliar concentrations of total N (TN), soluble N (SN), chlorophyll (Minolta SPAD readings), NH₄–N and NO₃–N as indicators of soil N availability in nectarine, Prunus persica L. Batsch, cv. ‘Fantasia’ (grafted on ‘Nemaguard’ peach, P. persica × P. davidiana) trees. Young trees were exposed to a range of fertilizer-N application rates. Based on correlation analysis, the best association between leaf N compounds with soil N supply and trunk diameter and/or fruit yield was obtained with TN and chlorophyll SPAD readings. Leaf concentrations of mobile N compounds (NH₄–N and NO₃–N) increased more than any other N compound under high N supply; however, their inconsistency among years and low leaf concentration difficult their use as N indicators. The optimum foliar TN for growth decreased with tree age, 4.4%, 3.6% and 3.3% in non-bearing 1-year-old trees, non-bearing 2-year-old trees and 3.3 fruit-bearing 3-year-old trees. The optimum SPAD readings were 40 in 2-year-old trees and 42 in 3-year-old trees. Stable N compounds (TN and chlorophyll SPAD) could be used to N diagnosis in the zone of N deficiency, and soluble N compounds (NH₄–N and NO₃–N) to diagnoses N excess.     

环渤海湾和黄土高原‘富士’苹果园土壤养分与果实矿质元素关系的多变量分析

探讨中国环渤海湾和黄土高原两大苹果产区土壤养分对‘富士’苹果果实矿质元素含量的影响及相互关系,为两大苹果产区提高果实矿质元素含量的果园合理施肥等提供理论依据。2010—2011年分别在中国环渤海湾和黄土高原两大苹果产区各选择22个县,每县3个果园,共计132个乔砧‘富士’苹果园,对每个果园的土壤养分和果实矿质元素含量进行调查和分析,比较两大产区土壤养分、果实矿质元素含量的差异,应用偏最小二乘回归方法筛选不同产区影响果实矿质元素含量的主要土壤养分因子,线性规划求解优质果实矿质营养丰富的土壤养分含量优化方案。结果表明:环渤海湾产区的土壤碱解氮、有效磷、钙、铁和锌含量极显著高于黄土高原产区,而土壤pH和有效钾含量显著低于黄土高原产区;环渤海湾产区‘富士’果实氮、磷含量显著高于黄土高原区,而钙、铁和锌含量则显著低于黄土高原产区。黄土高原产区土壤有效铁、环渤海湾产区土壤有效硼含量分别与果实中的铁、硼呈显著和极显著相关。环渤海湾产区影响果实钙含量的主要土壤养分因子的大小顺序为土壤有机质、全氮、有效锌、有效硼、有效铁和有效钾,土壤有效锌对果实钙有最大的正效应系数,而土壤有效硼和全氮负效应系数较大;黄土高原产区对果实钙含量影响的主要土壤养分因子的大小顺序为土壤有效磷、有效锌、有机质、有效铁和有效钾,土壤有效锌、铁对果实钙含量有较大的正效应系数。线性规划求解出两大苹果产区果实矿质元素含量丰富的土壤养分优化方案。环渤海湾苹果产区增加果实钙含量的主要土壤养分管理措施为降低土壤全氮、碱解氮含量,提高土壤有效钾、铁、锌含量,维持较高的土壤有机质含量(17.7 g·kg~(-1)以上);黄土高原产区则为提高土壤有机质、有效锌含量,降低土壤全氮、碱解氮含量,保持适宜的土壤有效磷、钾含量。     

Restoring the iconic Ulmus americana to urban landscapes: Early tree growth responds to aboveground conditions

Native trees provide a range of benefits, from supporting native wildlife to climate regulation, and many urban natural resource managers prioritize native tree planting and restoration. Ulmus americana (American elm) was once widely planted in American cities but has been decimated by Dutch elm disease (DED; Ophiostoma ulmi). Our study evaluated U. americana establishment and growth across urban landscapes. We planted ramets from three DED-tolerant U. americana genotypes (RV16, RV474, and Sunfield) along an urbanization gradient in Newark, DE and Philadelphia, PA, and assessed physiological and morphological responses. We analyzed how U. americana clone growth, chlorophyll fluorescence, and foliar chemistry relate to impervious surface area, ozone (O₃) concentrations, and soil characteristics. The one-year post planting mortality rate was low (4%) demonstrating these elms can withstand urban environmental conditions when provided ample water supply and protection from deer. As expected, the elms differed in growth rate, chlorophyll fluorescence, and foliar chemistry between the cities. Elms planted in Philadelphia had greater photosynthetic capacity in July (F_v/F_m = 0.76) and September (F_v/F_m = 0.75), while Newark elms had greater photosynthetic capacity in August (F_v/F_m = 0.78). Depleted foliar δ¹³C signatures in Philadelphia suggest elms are experiencing greater fossil-fuel derived atmospheric CO₂ than in Newark, possibly contributing to the greater growth rates observed in Philadelphia compared to Newark. Enriched foliar δ¹⁵N and greater foliar %N in Philadelphia clones suggest they are experiencing greater N deposition from NO_x-derived sources compared to Newark clones. Clones growing in Philadelphia had greater foliar nutrient concentrations despite growing in soils with greater heavy metal concentrations. These foliar-soil chemistry patterns suggest that clones growing in Philadelphia respond positively to urban environmental conditions in a large city, whereas clones growing in Newark may be experiencing N limitation in the first year of growth after planting.     

The influence of the topographic position within highlands of Western Rwanda on the interactions between banana (Musa spp. AAA-EA), parasitic nematodes and soil factors

Soil properties vary according to the topography. They affect water uptake and root exploration in the soil. Consequently, they may also influence the spread of plant–parasitic nematodes. This study reports on the effect of toposequence-related variations in soil on banana yields, foliar nutrient status, and nematode impact. Twenty banana plots were visited within 6 hills/valleys at each of the three toposequence positions: valley bottom, mid-slope and crest. Important variability in plant growth, nutrition and soil properties was observed within the toposequence. Significantly better plant growth (height and girth) was observed in the valley bottoms, where banana bunch weight was 1.7–3.4 kg higher (although not significant) than at upper toposequence positions. Best plant growth was observed in valley bottoms in contrast to the highest N and K foliar deficiencies in this position. Plants in the valley bottoms had higher foliar Ca and Mg, and K compared to those in the crest. Plants in the mid-slope had greater percentage of dead roots (19.1%), compared to the plants in the valley bottoms (12.3%) and the crest (14.2%). Soils in the valley bottoms were deeper, sandier, with lower organic matter, lower N, and K compared to the soils at higher toposequence. Nematodes likely play a key role in banana root damage, however, their effect appear to be in relation to various soil factors at each position. The abundance of Pratylenchus goodeyi had generally limited impact on banana yields in fields having less than 5% slope (crest and valley bottom) where soil conditions were more optimal for root growth. However, in the presence of increased run-off on steeper middle slopes, root death was increased even under moderate pressure from P. goodeyi.     

提高果树肥料利用率的方法

肥料作为果树生产的基础,决定着果实的产量和品质。合理使用氮肥、磷肥、钾肥、有机肥,结合果园的生产管理并采用合理的方法对于提高肥效的利用率是非常重要的;在果树不同的生长发育阶段施用不同种类的肥料至关重要,同时适当进行叶面喷肥将减少环境污染。综合以上措施可以大大改善土壤的理化性状,增强土壤的保水保肥能力,提高果树的肥料利用率。     

Light penetration,growth, and fruit productivity in ‘Fuji’ apple trees trained to four growing systems

The study was conducted to document the range in soil nutrients, trunk and shoot growth, leaf characteristics and nutrient content, flower bud characteristics, yield, fruit quality, disease occurrence, light penetration, and shoot bark color in a 15-year-old ‘Fuji’ apple (Malus × domestica Borkh.) orchard on M.26 rootstocks trained to four growing systems. SS trees naturally growing had greater width and volume than the LT lightly heading, MLT heavily heading, and S trees thinning and bending. LT trees had more upward terminal shoots at old branches, large numbers of lateral shoots, and longer total shoot length. Leaf [N], [P], and [K] were the lowest for the MLT trees. SS and S trees had greater flower bud density and fruit yield, but LT trees had poor fruit color and less soluble solids and firmness. Percent light penetration into the canopy was the highest with the S system but not different from MLT or SS. The lowest was for the LT system, however, it was not statistically different from MLT or SS.     

根际注射施肥对渭北苹果园土壤理化特性、土壤酶、果实产量及品质的影响

【目的】为探索根际注射施肥在苹果生产中应用。【方法】以10 a生红富士/M26/基砧为试材,利用施肥枪注射施肥,研究了不同浓度注射液对注肥点0～60 cm土层土壤理化特性、土壤酶、果实产量及品质的影响。【结果】随注射液浓度增加,各土层土壤pH值减小,电导率、碱解氮、速效磷和速效钾含量增加,各养分含量均为中层(20～40 cm)>表层(0～20 cm)>底层(40～60 cm);转化酶逐渐增大,过氧化氢酶和脲酶活性以10%浓度最高,磷酸酶活性以5%浓度最高。注射液浓度与中层土壤转化酶活性和碱解氮、速效磷、速效钾及电导率呈正相关。果实产量和单果质量分别以15%和10%浓度最高(2者无差异),硬度、可溶性固形物分别在0～10%和0～15%内逐渐增加,可滴定酸含量在0～10%内逐渐减小。【结论】综合分析以10%注射液浓度较适宜。     

Potassium fertilization of rainfed olive orchards

Experiments under both greenhouse and field conditions were performed to study the influence of the type of salt applied (KCl or K₂SO₄) and to compare the effectiveness of their method of application (soil versus foliar) on leaf K concentration and yield in olive trees established under rainfed conditions. In the experiment performed in the greenhouse, mist-rooted 3-month-old ‘Picual’ olive plants growing in 2-l pots containing perlite were irrigated with a complete nutrient solution containing either 0.05 or 2.5 mM KCl during 128 days after transplanting (DAT). A group of plants received one K soil application at a dose equivalent to 1 kg of K per tree at 63 DAT. Another group received four foliar applications at 63, 78, 93 and 108 DAT with a K concentration of 10.5 g/l. The experiment under field conditions was developed with 80-year-old ‘Hojiblanca’ olive trees. Soil application was performed in March every year at a rate of 1 kg K/tree by injecting K fertilizer around the trees. Foliar sprays were carried out in April, March, June and July every year with the same K concentration used for the greenhouse experiment. The results showed that, under both field and greenhouse conditions, either KCl or K₂SO₄ increased K concentration in leaves. Also, both K salts had a positive effect in increasing K content in fruits under field conditions, although the intensity of the increase varied among years. Tree water stress and low K status seemed to influence K uptake. The method of K application, soil or foliar, did not affect the effectiveness of K fertilization.     

不同施肥方式对苹果钙素吸收及土壤养分的影响

在大田条件下,研究了单施有机肥和有机肥配施化肥(混施)处理对苹果果品钙素吸收及土壤养分的影响。结果表明:单施有机肥土壤剖面硝态氮变化量不大,但可显著增加0~30 cm土层有机质含量,而混施可造成深层土壤硝态氮的累积,累积可达到120 cm土层。单施有机肥显著提高了果品钙素含量,与混施相比单施有机肥处理下SOD酶活性增加了21.82%,果实硝态氮含量降低了77.46%,说明当地有机肥的施用量基本维持了果园生态系统的碳、氮平衡,单施有机肥促进了果品钙素的吸收,对改善果实品质,促进果实硝态氮的转化,调节土壤硝酸盐含量变化有着很好的效果,而混施土壤硝态氮的累积可能在一定程度上抑制了苹果树对钙素的吸收。     

钙镁肥配施对苹果树叶片和果实营养元素含量及病果率影响

对大连瓦房店地区10 a树龄红富士苹果树进行不同的钙、镁肥的施肥处理,在喷与不喷硫酸镁溶液的基础上分别进行硝酸钙土施和喷施以及氨基酸钙喷施,探讨苹果叶片和果实营养元素含量及苹果"苦痘病"病果率状况。结果表明:钙的不同施肥方式和不同钙镁组合处理对苹果树各器官营养元素以及病果率影响差异很大。单独施钙和钙镁配合施用均不同程度提高了叶片中N、P、K、Ca、Mg的含量,而单施镁会降低营养枝叶片中Ca含量。Ca、Mg单施和配施均显著提高了果实中的P含量;Ca对苹果果实N吸收累积具有抑制作用;而Mg则有促进作用。与CK比较,单施Mg处理使得病果率提高了9.5%;单施Ca处理较Ca、Mg配施防病效果更明显。各施钙处理均显著降低了苹果"苦痘病"发病率;不施Ca、Mg处理病果率为4.2%,喷施氨基酸钙、硝酸钙和土施硝酸钙处理病果率分别为0.9%、1.4%、1.2%,病果率依次降低了79%、67%、71%;在施钙的基础上加施硫酸镁后病果率分别为1.9%、2.4%、2.2%,病果率依次降低55%4、3%、48%。钙肥处理以氨基酸钙肥喷施效果最好,而镁肥会加重苹果"苦痘病"的发病率。     

多效唑在苹果幼树上应用

红星、红富士苹果幼树施用多效唑后，对抑制新梢生长、调节枝条组成、促进花芽形成、提高坐果率、增加幼树产量、控制树冠增长均有明显效果，效果大小与施用方法、时期、药剂浓度和剂量、品种有关，土施比叶喷效果好。土施以３月或９月施入为宜，叶喷的最佳时期为５月上旬。土施的适宜剂量为０．５一１．０ｇ·ｍ~(-２)，叶喷最适浓度为１５００一２０００ｍｇ·１~(-１)。红星比红富士对药剂反应敏感。多效唑施后的持效期土施比叶喷的长，并随着剂量和浓度的增加而延长。土施０．５一１．０ｇ·ｍ~(-２)持效期为２一３年，叶喷１５００一２０００ｍｇ·１~(-１)的持效期仅为１年。     

Closed cycle subirrigation with low concentration nutrient solution can be used for soilless tomato production in saline conditions

Closed cycle soilless techniques can be adopted to minimize water and fertilizer losses in greenhouse cultivation. There is a general lack of information regarding the soilless cultivation of vegetables with closed cycle subirrigation techniques, specifically when using saline water. In this study, a trough bench subirrigation system (SUB), with two fertilizer concentrations (“100%”, containing 9.8 mol m⁻³ N-NO₃, 1.6 mol m⁻³ P-H₂PO₄, 8.7 mol m⁻³ K⁺, 2.8 mol m⁻³ Ca⁺, 1.8 mol m⁻³ Mg⁺, 4 mol m⁻³ S-SO₄, and “70%”, containing 70% of the macronutrient concentration) in the nutrient solution (NS), was compared with open cycle drip-irrigation (DRIP with “100%” NS). For all the three treatments, NS was prepared using rain water (0.05 dS m⁻¹) and adding NaCl (1 g L⁻¹), in order to simulate moderate saline irrigation water. The effect of the treatments on tomato (Solanum lycopersicum L.) plant growth, yield, fruit quality, water use efficiency (WUE) and fertilizer consumption was evaluated. Substrate and recirculating NS composition were also studied. Subirrigation, regardless of NS concentration, reduced plant height (by 30 cm), leaf area (by 1411 cm²), total fresh and dry weight (by 429 and 48.5 g plant⁻¹, respectively) but not dry matter percentage of the whole plant, with respect to DRIP. Yield was reduced when plants were subirrigated with the higher concentrated NS, but no differences with open cycle DRIP were recorded when the lower NS concentration was used in SUB. Fruit quality was not affected by irrigation system or NS concentration. The higher WUE was obtained with subirrigation. NaCl accumulated similarly over the crop cycle in recirculating NS of both SUB treatments and in growing substrates of all the three treatments. Higher salt concentration was found in subirrigated substrates, in particular in the upper part of the substrate profile. Fertilizers accumulated in the subirrigated substrates when the higher NS concentration was used, but not when the NS concentration was reduced by 30%. The results of this study indicate that tomato can be grown successfully in a closed cycle subirrigation system, using saline water, by reducing the fertilizer NS concentration normally used with traditional open cycle systems.     

中国苹果化肥减量增效技术途径与展望

在中国贫瘠的果园土壤条件下,化肥在苹果增产过程中发挥了重要作用,同时不合理的化肥使用也带来了肥料利用率低、果实品质下降、土壤质量降低、水体富营养化和温室气体排放等问题。因此,科学施肥提高化肥利用率,减少由于化肥损失带来的环境污染是关系到苹果产业能否实现绿色可持续发展的重大科技问题。分析了中国苹果养分管理中存在的问题,综述了当前已有的苹果化肥减量增效技术,主要包括障碍性土壤改良与培肥地力、最佳养分管理、根层养分调控和新型肥料与"大配方、小调整"区域配肥技术,并对今后苹果化肥减量增效技术的研究进行了展望。     

河北葡萄园施肥与土壤养分演变及其对产量的影响

以2007、2009、2011、2014年河北省张家口沙城产区与秦皇岛昌黎产区不同葡萄园为研究对象,采用葡萄园数据调研与葡萄园土壤养分含量分析的方法,揭示河北省葡萄主产区果园施肥量及土壤养分变化规律,明确施肥与土壤养分对产量的贡献,确定合理的施肥阈值。结果表明:2007-2014年河北省葡萄园有机肥投入逐年递减,化肥用量逐年递增,三元复合肥由52.0%增加至94.2%;土壤有机质含量偏低且逐年下降;N、P2O5、K2O含量丰富,总体呈现上升趋势;养分含量随土层深度而降低。氮磷钾养分投入量对产量的贡献率分别是13.59%、10.87%、13.19%;N、P2O5、K2O含量对产量贡献率分别是14.26%、14.76%、13.94%。鉴于河北省葡萄园有机肥投入量逐年降低,化肥投入量逐年升高,土壤有机质含量低,氮磷钾养分残留量大的现状表现,以期为葡萄园合理施肥提供参考依据。