Distribution and Accumulation of Nutrient Elements in Organic Tissue of Eucalyptus grandis Saplings

The biomass, macroelements （N, P, K, Ca, Mg） and microelements （Fe, Zn） contents were detected in organs of 1a-3a Eucalyptus grandis saplings, as well as their accumulated amount. Results showed that contents of nutrient elements varied greatly in different organs. Total contents of macroelements N, P, K, Ca and Mg in1a-3a E. grandis were distributed in the order of stem phloem, leaves 〉 branch- es, roots 〉 stem xylem. Accumulated amount of macroelements in 1a-3a E. grandis were in the order of leaves 〉 branches 〉 stem phloem 〉 roots or stem xylem 〉 stem xylem or roots. Accumulated amount law of nutrient elements was not affected by the plant age. Microelements Fe and Zn were mainly concentrated in the leaves and roots. The accumulation of macroelements was in the order of Ca 〉 N 〉 K 〉 Mg 〉 P; and the microelements was in the order of Fe 〉 Zn. Accumulated amounts of microelements in 1a-3a E. grandis were 12.45 136.19 and 420.23 g per plants, respectively. Among the annual net accumulated amount of nutrient ele- ments per plant in 1a-3a E. grandis, Ca element was the maximum, N and K ele- ments took the second and third places. Mg element was relatively small and P el- ement was the minimum.

Seasonal characteristics of Carex lasiocarpa biomass and nutrient accumulation in the typical wetland of Sanjiang Plain, China

Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.

Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen(N), phosphorus(P), and potassium(K) uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development,increased nutrient accumulation, and increased yield. Compared with conventional soil management(CK), root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm(T1) and subsoil tillage to 50 cm(T2) were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments.

Dynamics of Nutrient Accumulation in Maize Plants Under Different Water and N Supply Conditions

The dynamics of accumulations of plant dry matter, nutrient uptake and N fertilizer recovery were studied with different water and N supply, using summer maize (Zea mays L. var. Shandan9) as an indicator crop. The total dry matter (including roots) and N, P, K uptake amounts were continuously increased with plant growth, and their accumulations with time during plant-growing period were shaped in S curves that could be described by exponential regression equations. Differentiating the regression equations fitting the curves over time for first derivatives, the momentary rate was obtained of the dry matter and nutrient uptake. Results show that the dry matter and the nutrient uptake were not in the same rate at all time, but changed from one time to another. Usually, the rate increased rapidly at early stages, and gradually decreased after reaching their peak. Of N, P and K, the uptake rate of N and K was higher, and their increase and decrease were both fast while P was reversed. The time of the maximum absorptive rate appeared earlier for K, followed by N, and then by P. In any case, the maximum nutrient uptake rate appeared earlier than did the dry matter. The momentary N recovery rate was similar in trend to those of dry matter and N uptake, and its maximum recovery rate occurred almost at the same time as its maximum uptake rate. Supplemental irrigation raised the cumulative and momentary rates of N. Although water and N supplies increased dry matter and nutrient uptake rates, they did not alter their changing trends during the plant-growing period.

Nutrient Accumulation and Distribution of Mature Pinus massoniana Plantation in Northwestern Guangxi

[Objectives]This study was conducted to reveal the characteristics of nutrient absorption and accumulation in Pinus massoniana plantations in Northwestern Guangxi.[Methods]Based on field investigation and indoor analysis,the contents,accumulation and annual net accumulation of five nutrient elements(N,P,K,Ca and Mg)in a mature P.massoniana plantation(26-year-old)in Nandan County,Guangxi Province were studied.[Results]The contents of nutrient elements in different organs of the mature P.massoniana plantation were the highest in the leaves,followed by the bark,branch and root,and the lowest in the stem.In general,among the contents of the five elements in different organs,N content was the highest,followed by K or Ca,and P and Mg were the lowest.The total accumulation of nutrient elements in the 26-year-old mature P.massoniana plantation in northwestern Guangxi was 1 384.05 kg/hm^2.Among the different structural levels of the stand,the tree layer had the highest accumulation of nutrient elements,which was 1 198.41 kg/hm^2,accounting for 86.59%of the total accumulation of nutrients in the plantation,and the accumulation of nutrients in other layers from the largest to the smallest was the litter layer(91.97 kg/hm^2),herb layer(49.86 kg/hm^2)and shrub layer(43.92 kg/hm^2),accounting for 3.17%,3.60%and 6.64%of the total nutrient accumulation of the plantation,respectively.The annual net accumulation of nutrient elements in the tree layer of the mature P.massoniana plantation was 46.09 kg/(hm^2·a),and the order of the annual net accumulation of different nutrient elements followed N>K>Ca>Mg>P;and the accumulation of 1 t of dry matter needed 6.37 kg of the five nutrients.[Conclusions]This study provides a scientific basis for the rational management of P.massoniana plantations,especially forest soil management.

Biomass Accumulation and Nutrient Uptake of Jerusalem Artichoke (<i>Helianthus tuberosus</i>L.)

The dynamics of biomass accumulation during the growing period, the yield of leafy stalks and tubers, and the nutrient concentration and nutrient uptake of the yield were investigated for two Jerusalem artichoke varieties (Tápiói Korai and Tápiói Sima) in a field experiment involving mineral fertilisation. Considerable differences were observed between the dynamics of leafy stalk and tuber development in Tápiói Korai which has a short vegetation period and Tápiói Sima where the vegetation period is long. The maximum dry matter ratio between the tuber yield and the leafy stalk yield was 1:1 for Tápiói Korai and 1:4.5 for Tápiói Sima. During the period when the maximum aboveground biomass developed in Tápiói Korai, 100 kg.ha-1 N and P fertiliser resulted in the highest leafy stalk yield (38.34 t.ha-1), while for Tápiói Sima, which developed a much greater leafy stalk mass, the highest aboveground biomass yield (78-80 t.ha-1) was given in response to 200 kg.ha-1 N supplemented by P and K fertiliser. Both artichoke varieties produced the great-est tuber yield at a N rate of 200 kg.ha-1, supplemented with P and K fertiliser. The nutrient concentration in the leafy stalks was highest on the 85th day of the vegetation period, prior to intensive dry matter accumulation in the leafy stalks and before tuber formation began. In both varieties the maximum nutrient uptake was recorded on the 155th day. Great differences were observed between the varieties in terms of specific nutrient uptake. For a tuber yield of 10 t, together with the corresponding leafy stalk yield, the specific nutrient uptake of the Tápiói Korai variety amounted to 48 kg N, 10 kg P, 83 kg K, 30 kg Ca and 10 kg Mg, while for Tápiói Sima these figures were 162 kg N, 30 kg P, 300 kg K, 84 kg Ca and 45 kg Mg.

Nutrient Accumulation and Distribution in Cotton Promoted by Removal of Mulch Film

Plastic film mulching affects changes in nutrient contents in soil and absorption and utilization of nutrients in plants were by changing hydrothermal condition of soil.The temporal and spatial variation of the total soil salt and nutrient contents with mulch film removed at three different times during the early cotton growth stage and its effects on nutrient absorption and accumulation in cotton plants were studied over 2015-2017.The film removal treatments reduced salt accumulation in normal rainfall year(2017).Film removal increased contents of soil organic matter,the total phosphorus and available potassium at the end of growth stage,increased contents of soil hydrolyzable nitrogen and the total nitrogen in the surface soil layer(0-10 cm),and increased the total nitrogen contents in the deep soil layer(40-50 cm).Film removal increased accumulation of nitrogen and phosphorus nutrients in cotton plants in 2017 and accumulation of nitrogen,phosphorus and potassium nutrients in cotton plants in heavy rainfall year(2016).These experimental results indicated that removal of mulch film at an appropriate and targeted time in the bud stage of cotton promoted nutrient absorption.

Nutrient Accumulation Characteristics of Facility Soils with Different Planting Years in Lateritic Red Soil Region of Guangxi

[Objectives]To explore the nutrient accumulation characteristics of facility soil in different planting years in the lateritic red soil region of Guangxi.[Methods]The soil samples of facility cultivation and open field cultivation were collected in the lateritic red soil region of Guangxi,and the changes of soil pH,water-soluble salts,organic matter,available nutrients and total nutrients were analyzed.[Results]The acidification of the facility soil in the lateritic red soil region of Guangxi became more obvious with the extension of greenhouse planting years,the soil pH decreased by 0.34 units after continuous planting for 10 years,and the water-soluble content was more than 3 times that of the open field and it increased with the extension of the planting years.In addition,the degree of secondary salinization in facility soil became more serious,mainly moderate and mild salinization.The contents of soil organic matter,alkali-hydrolyzed nitrogen,available phosphorus,available potassium,total nitrogen and total phosphorus in the facility soil increased significantly,while total potassium did not change significantly.[Conclusions]This study is expected to provide a scientific basis for facility soil fertilization management,and to promote the sustainable and healthy development of facility cultivation industry.

Effect of Long-Term Fertilization on Soil Productivity and Nitrate Accumulation in Gansu Oasis

A long-term （1982-2001） field experiment was conducted in a calcareous soil under wheat （Triticum aestivum L.）-wheat （Triticum aestivum L.）-maize （Zea mays L.） rotation system at Zhangye, Gansu Province, China to determine the effects of long-term fertilization on crop yield, nutrients interactions, content and accumulation of nitrate-N in soil profiles. Twenty- four plots in a split-plot factorial with a combination of eight treatments （from nitrogen （N）, phosphorus （P）, potassium （K） and farmyard manure （M） applications） and 3 replications were selected. Main treatments were M and without M, and the sub-treatments were no-fertilizer （CK）, N, NP and NPK. When P and K fertilizers were part of treatments, their ratio to N was 1N：0.22P：0.42K. All M, P and K fertilizers were applied as the basal dressing. The grain yield was harvested each experimental period and straw yield for the period from 1988 to 1997. After crop harvest in 2000, the soil was sampled from the 0-20, 20-60, 60-100, 100-140 and 140-180 cm depths to determine NO3^--N content. Maize yield of CK in 2000 was only 28.2% of that in 1984, and wheat in 2001 was 25.7% of that observed in 1982. Average impact of fertilizers on grain yield decreased in the order of N 〉 M 〉 P 〉 K. Yield response to N and P fertilizers increased with progress of the experiment. The impact of K fertilizer showed no increase in grain yield during the initial 6 years （1982-1987）, moderate increase in the next 5 years （1988-1992）, and considerable increase in the last 9 years （1993-2001）. The straw yield trend was similar to grain yield. Accumulation and distribution of NO3^--N in soil was significantly affected by annual fertilizations. Mineral fertilizers （NP and NPK） led to NO3^- -N accumulation in most subsoil layers, with major impact in the 20-140 cm depth. The combination of mineral fertilizers and farmyard manure （MNP and MNPK） reduced soil NO3^--N accumulation in comparison to mineral fertilizers, It can be argued that long-term fertilization significantly enhanced grain and straw yield in this rotation scheme. The findings of this research suggest that it is important to balance application of mineral fertilizers and farmyard manure in order to protect soil and underground water from potential NO3^--N pollution while sustaining high productivity in the oasis agro-ecosystem.

Dynamics of Above-and Below-ground Biomass and C,N,P Accumulation in the Alpine Steppe of Northern Tibet

The temporal dynamics of the biomass, as well as the carbon （C）, nitrogen （N）, phosphorus （P） concentrations and accumulation contents, in above- and below-ground vegetation components were determined in the alpine steppe vegetation of Northern Tibet during the growing season of 2OLO. The highest levels of total biomass （311.68 g m-2）, total C （115.95 g m-2）, total N （2.60 g m-2）, and total P （0.90 g m-2） accumulation contents were obtained in August in 2010. Further, biomass and nutrient stocks in the below-ground components were higher than those of the above-ground components. The dominant species viz., Stipa purpurea and Carex moorcrofli had lower biomass and C, N, P accumulations than the companion species which including Oxytropis. spp., Artemisia capillaris Thunb., Aster tataricus L., and SO on.

Distribution and Accumulation of Soil Carbon in Temperate Wetland, Northeast China

Estimating carbon sequestration and nutrient accumulation rates in Northeast China are important to assess wetlands function as carbon sink buffering greenhouse gas increasing in North Asia. The objectives of this study were to estimate accreting rates of carbon and nutrients in typical temperate wetlands. Results indicated that average soil organic carbon(SOC), total nitrogen(TN) and total phosphorus(TP) contents were 37.81%, 1.59% and 0.08% in peatlands, 5.33%, 0.25% and 0.05% in marshes, 2.92%, 0.27% and 0.10% in marshy meadows, respectively. Chronologies reconstructed by 210 Pb in the present work were acceptable and reliable, and the average time to yield 0–40 cm depth sediment cores was 150 years. Average carbon sequestration rate(Carbonsq), nitrogen and phosphorus accumulation rates were 219.4 g C/(m^2·yr), 9.16 g N/(m^2·yr) and 0.46 g P/(m^2·yr) for peatland; 57.13 g C/(m^2·yr), 5.42 g N/(m^2·yr) and 2.16 g P/(m^2·yr) for marshy meadow; 78.35 g C/(m^2·yr), 8.70 g N/(m^2·yr) and 0.71 g P/(m2·yr) for marshy; respectively. Positive relations existed between Carbonsq with nitrogen and precipitations, indicating that Carbonsq might be strengthened in future climate scenarios.

Seaweeds as Biomonitoring System for Heavy Metal (HM) Accumulation and Contamination of Our Oceans

This research manuscript reports the heavy metal accumulation in four marine seaweeds sp. 1)?Caulerpa sertlatioides (Cuba);2) Caulerpa cf. brachypus;(Bali, Indonesia);3) Undaria pinnatifida (West-Donegal, Ireland);4) Ulva lactuca (Easters-Scheldt, the Netherlands). Mechanical pressure at 10 bar of fresh seaweed fronds casu quo biomass in the laboratory delivered seaweed moisture which was analyzed by Inductively Coupled Plasma Spectroscopy (ICP)-techniques for heavy-metals = [HM], (Al, As, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb & Zn). Three important observations were made: 1) The [HM] in the seaweed moisture is higher than in the surrounding seawater which directs to mechanism(s) of bio-accumulation;2) The accumulation factor [AF] is varying per metallic-cation with an overall trend for our four seaweeds and sampling locations for [HM] are: As & Co & Cu: 5000 - 10,000 μg/l;Ni & Zn: 3000 - 5000 μg/l;Cd: 2000 - 3000 μg/l;Cr: 1000 - 2000 μg/l;Al: 200 - 1000 μg/l;Mo & Pb & Fe: 0 - 200 μg/l range. 3) Seaweed moisture detected that [HM]: Pb & Zn & Fe—which all three could not be detected in the seawater—supports the view that seaweeds have a preference in their bio-accumulation mechanism for these three HM. Major conclusion is in general that “overall” for the macro-elements Ca, Fe, K, Mg, Mn, Na, P & S in the moisture of the four seaweed species the concentration is lower in the seaweed species, or equals the concentration, in comparison to the surrounding sea water. For the HM (Al, As, Cd, Co, Cr, Cu, Mo, Ni, Pb & Zn) the opposite is the case species and is the concentration “overall” higher in the seaweed species in comparison to the surrounding sea water. Further topics addressed include strategies of irrigation of the Sahara desert with the moisture out of seaweeds under conditions of low anthropogenic influences.

Spraying Arginine at 5 Days before Harvest Delays Postharvest Broccoli Senescence via Nutrient Accumulation

To determine the effects of preharvest arginine spraying on the nutritional level of broccoli and the mechanism of action of arginine in improving the storage quality of broccoli,arginine spraying(5 mmol/L)was conducted at 0,1,3,and 5 days before harvest.The appearance,respiration rate,mass-loss rate,electrolyte leakage,glucosinolate,ascorbic acid,total phenol,total flavonoid,total sugar and sucrose contents,and sucrose phosphate synthase(SPS),invertase(INV),sucrose synthase synthesis(SSS)and cleavage(SSC)activities of broccoli samples were observed after 0,2,4,6,8,and 10 days of storage.The results showed that spraying arginine at 5 days preharvest(5-ARG)helped to inhibit broccoli respiration during storage,delay electrolyte leakage,and maintain broccoli color.Furthermore,during the growth stage,total sugar accumulation was higher in the 5-ARG group.In addition,during the storage period,sucrose synthesis was accelerated,while sucrose cleavage was inhibited,resulting in more sucrose retention in postharvest broccoli.In conclusion,5-ARG resulted in the accumulation of more nutrients during the growth process and effectively delayed the quality decline during storage,thereby prolonging the shelf life of broccoli.Therefore,this study provides a theoretical basis for improving postharvest storage characteristics of broccoli through preharvest treatments.

Nutrient and Litter Patterns in Three Subalpine Coniferous Forests of Western Sichuan, China

Investigations were conducted to quantify litterfall, and litter and nutrient accumulation in forest floor, and to acquire information on litter decomposition and nitrogen and phosphorus release patterns in three different subalpine coniferous forests, a plantation （P1）, a secondary forest （SF）, and a primitive forest （PF）, in western Sichuan, China. The litter trap method was used to evaluate litterfall with the litterbag method being utilized for litter decomposition. Seasonal patterns of litterfall were similar in the three forests, with two peaks occurring in September-November and March-May. The plantation revealed an annual litterfall of 4.38 x 103 kg ha-1, which was similar to those of SF and PF, but P1 had a lower mass loss rate and a higher C/N ratio. The C/N ratio may be a sound predictor for the decomposition differences. N concentrations of leaf litter in both the secondary forest and primitive forest increased first and then decreased, and the percentages of their final/initial values were 108.9% and 99.9%, respectively. P concentration in the three forests increased by the end of the study. The results of litterfall and decomposition indicated that in the plantation the potential to provide nutrients for soil organic matter was similar to those of SF and PF; however, its slower decomposition rate could result in a somewhat transient accumulation of litter in the forest floor.

Impact of spacing and rotation length on nutrient budgets of poplar plantations for pulpwood

The above-ground biomass and nutrient accumulation by poplar plantations were evaluated for pulpwood production ]n China, Experimental treatments applied in a split-plot design included four planting densities (1111, 833, 625 and 500 stems hm-2), three rotation lengths (4a, 5a and 6a) and three poplar clones (1-69.NL-80351 and 1-72). The highest biomass was achieved in the highest stocked stand (1111 stem hm-2’) at 6 of rotation age for both clone 1-69 and clone 1-72, which is about two times that in the stands of 500 stems hm-2 at 4 ofrotation age. However, the highest occurred in the stand of 833 stems-hm-2 at 6-year rotation for NL-80351. Ranking of the plantation biomass production by component was stem > branches > foliage> stem--bark and the production of the Support components of the plantation was 10-fold that of the productive component, i.e., foliage. Thepattern of accumulation of nutrients by the plantations was similar to the biomass. Nutrient accumulation in theplantations was in the order of Ca>N>K>Mg>P, but some differences existed in annual nutrient accumulationrates for four planting densities and three poplar clones, The mean annual accumulation of N and P in the plantations was 13.2 and 2.8 kg hm-2 in stem, 12.1 and 1 .9 kg hm 2 in branch, and 98.5 and 9.5 kghm’ in foliage. Themean Ca, K and Mg accumulations were 28.2, 1 8.5 and 2.9 kg’hm-2 a-1, 26,9. 11,0 and 2.3 kg-hm-2-a-1 in branch.and 116.5, 81 .3 and 16, 1 kg hm-2 a-1 in foliage, respectively. Biomass utilization standards markedly affected theexport of nutrients from the site, Whole tree utilization yields the most biomass and removes the most nutrients,Removal of stem with 2 10-cm diameter exports about half of the biomass, but N and nutrients removals are only23% and 28% of the total, respectively, Removal of the entire stem provides about tWo--thirds of the total biomassand removes 31,1% total N and 37.5 % total nutrients respectively. Including the branches in the removal increases biomass yield to 92% of the total, and nutrient removal is about 68% of the total,

硝酸钾配施有机肥对早熟禾生长及养分吸收的影响

早熟禾草坪在盐碱土壤上建植3~4年后会发生明显的退化,研究园林养护中采用硝酸钾配施有机肥的方式为其提供营养,对促进植株生长和提高坪用质量具有重要意义。试验设置在城市绿化带中,设置空白对照(K1)、硝酸钾化肥对照(K2)、化肥+发酵饼肥(K3)、化肥+腐殖酸复混肥(K4)4个处理,每个处理3次重复,研究了早熟禾生长和养分吸收变化。结果表明:K3与K1相比,在7~10月有利于提高早熟禾干物质积累量、含水量、叶绿素a、叶绿素b和类胡萝卜素含量,显著提高了植株氮、磷、钾吸收量;K3与K2相比,在8~9月显著提高了干物质积累量,7月和10月显著提高了叶绿素b和类胡萝卜素含量,8~10月提高了氮磷钾养分吸收量;K3与K4相比,在7~9月提高了干物质积累量,7~10月显著提高了叶绿素b和类胡萝卜素含量,促进了氮磷钾营养元素的吸收。综合分析认为,硝酸钾配施发酵饼肥为适宜施肥处理。

广西不同绿肥油菜品种的养分累积差异及富硒品种筛选

【目的】探明不同绿肥油菜品种的养分差异及对土壤硒富集效应,为丰富绿肥油菜品种及广西富硒土壤资源应用提供理论依据。【方法】以川油36(CY36)、丰油823(FY823)和沣油919(FY919)等19个绿肥油菜品种为研究对象,采用盆栽试验,研究不同品种生物量,氮、磷、钾和钙养分累积差异及对土壤硒吸收、富集的响应。【结果】不同绿肥油菜品种之间的地上部生物量、地下部生物量和总生物量均存在一定差异。地上部干生物量为4.49~6.62 g/盆,地下部为0.14~0.84 g/盆;总干生物量为4.82~7.14 g/盆。总生物量前3位的中双9号、沣油958和南油12显著高于生物量最低的3个品种(花油8号、川油36和华湘油12号);地上部氮、磷、钾和钙养分含量分别为8.86~19.64 g/kg、 0.69~2.24 g/kg、 13.07~37.68 g/kg和11.82~34.23 g/kg。浙油51号和花油6号地上部和地下部的养分含量均较高。氮、磷、钾和钙含量综合评分排序前3位的油菜品种为浙油51、中双10号和花油6号。硒含量地上部为0.095~0.369 mg/kg,地下部为0.160~0.579 mg/kg;全株硒含量为0.111~0.382 mg/kg;沣油919、绵油88和圣光86的地上部、地下部和全株硒含量较高,均显著高于其他油菜品种;硒总累积量在0.552~2.286μg/盆,沣油919和绵油88显著高于其他油菜品种。【结论】综合各品种的养分累积量和硒素吸收特性,沣油919、绵油88和圣光86的富硒能力较强,可作为广西富硒土壤资源高效利用的绿肥油菜品种。

茭虾共作对土壤氮磷含量和茭白干物质积累及氮磷钾吸收分配的影响

为探究茭白种养模式的施肥策略,设置茭虾共作(ZC)、茭白单作(Z)2个处理,研究茭虾共作对土壤氮磷含量、茭白产量和茭白干物质积累及氮磷钾吸收分配的影响。2021-2022年的研究结果显示,茭虾共作模式较茭白单作模式采茭期土壤中全氮、全磷、速效磷的含量分别提高了10.85%~38.89%、5.45%~13.79%、6.19%~61.79%,净茭产量提高了5.10%~19.54%,采茭期茭白茎、叶、净茭的干物质积累量分别增加14.41%~16.58%、10.28%~15.15%、10.57%~21.45%。2021年茭虾共作处理较茭白单作处理在采茭期叶的氮含量显著增加了25.74%,但在孕茭期茎中磷含量显著减少了16.76%;2022年氮肥减量、减量投喂下,茭虾共作处理较茭白单作处理在孕茭期茎的氮含量显著减少了23.75%,在分蘖期叶中磷含量显著减少了12.08%,2a全生育期同一器官的钾含量在2个处理间差异不显著。对于养分积累,2021年茭虾共作处理在分蘖期叶的氮、磷、钾积累量较茭白单作处理分别减少26.04%、27.27%、30.11%,但在采茭期茎的氮、钾积累量和叶的氮、磷积累量较茭白单作处理分别增加18.80%、38.41%和44.77%、35.71%;2022年在氮肥减量、饲料减量投喂下,茭虾共作处理在采茭期叶的磷积累量和茎的钾积累量较茭白单作处理显著增加30.0%和30.77%。关于养分分配,2种处理的茭白在孕茭期和采茭期氮素的分配均以茎、叶为主,而磷、钾元素的分配均以茎为主,茎分配比例在42%~66%。对于养分转运,2021年2种处理茭白的根、茎、叶在氮、磷转运上大多为表现为“库”器官,而在钾转运上大多表现为“源”器官;2022年氮肥减量、减量投喂下,茭白的根、茎、叶在氮、磷、钾转运量上大多表现为“源”器官。因此,在茭虾共作模式中适当减少肥料、饲料的投入,能促进形成合理的源库关系,有利于茭白产量的形成。

配比施肥对柚木早期生长及叶片养分含量的影响

【目的】探究不同肥料配比对柚木幼树生长及叶片养分和叶绿素含量的影响,为确定适宜的柚木施肥方案提供参考。【方法】以柚木幼林为研究对象,采用随机区组试验设计,设置5种配比施肥处理(0.25 kg/株氮磷钾复合肥+0.25 kg/株钙镁磷肥(T1)、0.25 kg/株钙镁磷肥+2.50 kg/株有机肥(T2)、0.25 kg/株氮磷钾复合肥+0.25 kg/株氧化镁+10.00 g/株硼肥(T3)、0.25 kg/株氮磷钾复合肥(T4)、0.25 kg/株氮磷钾复合肥+1.50 kg/株钙镁磷肥(T5)),以不施肥处理为对照(CK),分析不同施肥处理柚木幼树生长量及叶片养分和叶绿素含量的变化,运用隶属函数法对不同处理的施肥效应进行综合评价。【结果】①与CK相比,不同配比施肥处理均可以提高柚木的树高、胸径和材积平均增量,其中均以T5处理柚木的树高、胸径和材积平均增量最高,较CK分别提高了44.81%,82.02%和108.72%。②与CK相比,不同配比施肥处理柚木叶片全N、全K、交换性Ca含量均无显著变化,但叶片全P、交换性Mg含量显著提升,叶片N/P值显著降低。③与CK相比,不同配比施肥处理均可以提高柚木叶片的叶绿素a、叶绿素b和总叶绿素含量,降低叶绿素a/b值,其中T5处理叶片叶绿素a和总叶绿素含量与CK差异达显著水平。④隶属函数法评价结果显示,5种配比施肥处理的肥料效应由大到小排序为T5>T3>T2>T1>T4。【结论】5种配比施肥处理均可促进柚木叶片对钙、镁、磷营养元素的吸收与累积,加快叶绿素的合成,促进柚木幼树生长量的增加,其中0.25 kg/株氮磷钾复合肥+1.5 kg/株钙镁磷肥为最佳肥料组合。

不同轻型基质对杉木容器苗生长与养分积累的影响

为筛选出适合杉木优良无性系洋-061容器苗生长的轻型基质配方。采用单纯形-重心混料试验设计,以泥炭土、珍珠岩、杉木皮和稻谷壳为材料,并以黄心土为对照(CK),研究不同轻型基质配比对杉木生长、根系形态和养分积累的影响。结果表明,1)不同轻基质配方(T1-T14)和对照(CK)处理的苗高、地径和生物量均表现出相同的生长规律,即随时间增加而逐渐增大。2)当苗木培育360 d时,不同轻型基质处理苗高、地径和苗木质量指数均高于CK,其中,苗高在T6处理最大,较CK增加了54.89%,地径和苗木质量指数在T6和T1处理时达到最大,分别较CK提高33.04%和48.65%,T14处理下生物量最大;3)不同轻型基质处理有效促进了杉木幼苗根系的发育,而且其总根长、根表面积、根直径及根体积分别在T2、T14、T9和T14处理时达到最大;4)杉木植株养分含量对不同轻型基质响应存在差异,其中轻型基质T5、T3和T12处理显著促进植株氮的积累,轻型基质T8、T3和T13处理苗木全磷含量显著高于其他处理,而T8、T9和T2植株全钾含量显著高于其他处理;5)利用隶属函数对幼苗生长指标进行综合分析,综合评价排名前3的依次是T14(20%泥炭土+27%珍珠岩+27%杉木皮+26%稻谷壳)、T5处理(60%泥炭土+40%珍珠岩)和T1处理(100%泥炭土)。考虑到泥炭土成本较高,因此,T5和T14处理为本研究中适合于杉木洋-061容器苗生长的轻型基质配方。