The Application of Fertilizer and AMF Promotes Growth and Reduces the Cadmium and Lead Contents of Ryegrass (Lolium multiflorum L.) in a Copper Mining Area

Heavy metal-polluted soil was collected from the Pulang copper mine in Shangri-La City,Yunnan Province,Southwest China.The effects of fertilizer(organic and inorganic)and arbuscular mycorrhizal fungi(AMF)on ryegrass(Lolium multiflorum L.)growth,root morphology,mineral nutrition and cadmium(Cd)and lead(Pb)contents were investigated by pot experiments.The results showed that both fertilizer and AMF significantly ameliorated the root morphology and mineral nutrition,reduced the Cd and Pb contents,and promoted the growth of ryegrass.Among all treatments,the combined application of organic–inorganic compound fertilizer with AMF had the highest effect,resulting in increases in root length,surface area and branch number by 2.3,1.1,and 3.9 times,respectively;an 88%increase in plant biomass;a nitrogen content increase of 2.3 and 1.2 times,and phosphorus content increase of 62%and 68%in shoots and roots,respectively was also recorded as well as decreases in Cd content by 34%and 62%and Pb content by 47%and 34%in shoots and roots,respectively.Twofactor analysis showed that both fertilizer and AMF significantly promoted ryegrass growth(plant height,biomass,chlorophyll content,root length,nitrogen and phosphorus content)and reduced the Cd and Pb contents in roots,and there was a synergistic effect between them.Moreover,the nitrogen and phosphorus contents were very significantly positively correlated with the shoot and root biomasses but very significantly negatively correlated with the Cd and Pb contents of ryegrass.Thus,the application of fertilizer and AMF synergistically improved ryegrass growth on polluted soils in the copper mining area.

Effects of Different Application Rates of Pesticides and Chemical Fertilizers on Wheat Stripe Rust and Wheat Yield

[Objectives]The paper was to investigate the effects of different application rates of pesticides and fertilizers on wheat stripe rust and wheat yield.[Methods]Two-factor split block design was adopted.[Results]Different application rates of pesticides and chemical fertilizers would affect the incidence of wheat stripe rust,and further affect the yield of wheat.Triadimefon had no significant effect on wheat yield,and potassium sulfate compound fertilizer had significant effect on wheat yield,while their interaction had no significant effect on wheat yield.There were significant differences in wheat yield among the 15 treatment combinations,which may be due to the fact that the application rate of potassium sulfate compound fertilizer had extremely significant effect on wheat yield.[Conclusions]Under the wheat/green manure/maize zonal rotation system in Bijie,the sowing width of wheat is guaranteed to be 0.5 m under the 1.65 m zonal cropping system,and the sowing rate of wheat is arranged according to the basic seedling of 1.2 million plants/hm^(2).In the early stage of wheat stripe rust,15%triadimefon WP can be sprayed evenly at the dose of 1050 g/hm^(2)by a high-power sprayer in a sunny day.

In situ polymerization coating and characteristics of coated NPK compound fertilizer

Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature.Methacrylate,α-methyl acrylic acid,and ethylene dimethylacrylate were used as monomers,Dibenzoyl peroxide as initiator,and cobalt naphthenate,and triethyl amine as promoters.The structures of coating materials were characterized by IR spectra.The thermogravimetric analysis result indicated that the coating materials were of good thermal stability.The mean thickness of single coating measured with screw gauge was ca.140μm.The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating.The increase in coating hydrophicity caused the increase in release rate of fertilizer.The increase in thickness of coating slowed the release rate.

Release Characteristics of Different N Forms in an Uncoated Slow/Controlled Release Compound Fertilizer

This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer (UCRF) and the N uptake and N-use efficiency by rice plants. Water dissolution, soil leaching, and pot experiments were employed. The dynamics of N release from the UCRF could be quantitatively described by three equations: the first-order kinetics equation [Nt = N0 (1-e-kt)], Elovich equation (Nt = a + blnt), and parabola equation (Nt = a + bt0.5), with the best fitting by the first-order kinetics equation for different N (r = 0.9569** - 0.9999**). The release potentials (N0 values estimated by the first-order kinetics equation) of different N in the UCRF decreased in the order of total N > DON > urea-N > NH4+-N > NO3--N in water, and total N > NH4+-N > DON > urea-N > NO3--N in soil, respectively, being in accordance with cumulative amounts of N release. The constants of N release rate (k values and b values) for different N forms were in decreasing order of total N > DON > NH4+-N > NO3--N in water, whereas the k values were urea- N >DON > NH4+-N > total N > NO3--N, and the b values were total N > NH4+-N > DON > NO3--N > urea-N in soil. Compared with a common compound fertilizer, the N-use efficiency, N-agronomy efficiency, and N-physiological efficiency of the UCRF were increased by 11.4%, 8.32 kg kg-1, and 5.17 kg kg-1, respectively. The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants. The findings showed that the first-order kinetics equation [Nt = N0 (1-e-kt)] could be used to describe the release characteristics of different N forms in the fertilizer. The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.

Yield and quality responses of citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to compound fertilizers

Experiments were carried out with citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to study the effects of compound fertilizers on their yields and quality. In the citrus experiment, application of compound fertilizers increased available P, K and Mg contents in soil but decreased alkali-hydrolyzable N contents in soil and N, P and K contents in leaves. In the tea ex- periment, application of compound fertilizers increased available P, K and Mg contents in soil and N, P, K and Mg contents in leaves but decreased alkali-hydrolyzable N in soil compared with the urea treatment. Application of compound fertilizers could improve the quality of citrus and tea, increase their yields and enhance their economical profits significantly. Compared with the control, application of compound fertilizers increased citrus yields by 6.31, 12.94 and 17.69 t/ha, and those of tea by 0.51, 0.86 and 1.30 t/ha, respectively. Correspondingly, profits were increased by 21.4% to 61.1% for citrus and by 10.0% to 15.7% for tea. Optimal rates of compound fertilizers were recommended for both crops.

Effects of Magnesium Compound with Fertilizer on Daylily (Hemerocallis citrina Baroni) Growth and Soil Nutrients

Effects of two kinds of magnesium compound with fertilizer on Daylily (Hemerocallis citrina Baroni) growth, yield, and soil nutrients in red soil were studied. The results indicated that significant effects of magnesium applied to soils were observed in increasing Daylily (Hemerocallis citrina Baroni) yield, improving its growth, and strengthening its antivirus property as well as increasing the amount of exchangeable Mg, N, P, and K in red soil. In particular, the effects of magnesium compound fertilizer Ⅱ(MCF2) with higher Mg content were better than that of the others, which increased Daylily (Hemerocallis citrina Baroni) yield by 57.4, 32.8, and 14.5% compared to that of control treatment (CK), chemical fertilizer with nitrogen, phosphorus, potassium treatment (CF), and magnesium compound fertilizer Ⅰ treatment (MCF1) with lower Mg content. It increased soil Alkali N, available P, exchangeable K, and exchangeable Mg by 94.9, 46.5, 31.1, and 35.3%, respectively, compared with that of CK treatment. Therefore, the application of magnesium compound with fertilizer is an optimum method for improving red soil quality.

Production of Potash and N-Mg Compound Fertilizer via Mineral Shoenite from Kunteyi Salt Lake:Phase Diagrams of Quaternary System(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O in the Isothermal Evaporation and Crystallization Process

Based on the requirement of the new technology for producing potassium sulfate and N-Mg compound fertilizer,boussingaultite,by the reaction of the mineral shoenite from Kunteyi Salt Lake,Qinghai province,and the industrial by-product ammonium sulfate,the solubilities of the quaternary system(NH_(4))_(2)SO_(4)-MgSO_(4)-K_(2)SO_(4)-H_(2)O at 25.0℃in the isothermal evaporation and crystallization process were measured using the isothermal evaporation method,and the corresponding phase diagrams were plotted.According to the diagram,this system contains six saturation points and six solid phase fields of crystallization,which correspond to(K1-m,(NH_(4))m)_(2)SO_(4),(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O,K_(2)SO_(4)·MgSO_(4)·6H_(2)O,MgSO_(4)·6H_(2)O,(K1-n,(NH_(4))n)_(2)SO_(4)·MgSO_(4)·6H_(2)O and MgSO_(4)·7H_(2)O,respectively.By analyzing and calculating the isothermal evaporation and dissolution phase diagram of this quaternary system at 25.0℃,K_(2)SO_(4)and(NH_(4))_(2)SO_(4)·MgSO_(4)·6H_(2)O can be separated via K_(2)SO_(4)·MgSO_(4)·6H_(2)O and(NH_(4))_(2)SO_(4)as raw materials.Theoretical calculations about the proposed process were carried out and verified by experiment,which indicated that the yield of potassium sulfate was improved and the magnesium resources were fully utilized.

Effects of Different Compound Fertilizers on Growth and Quality of Ginger(Zingiber officinale Roscoe)

[Objectives] This study was conducted to screen compound fertilizers suitable for ginger( Zingiber officinale Roscoe). [Methods]The effects of several different compound fertilizers on the growth,development,yield,and quality of ginger were compared under field test conditions. [Results] Treatment T2( 17-9-19) could effectively promote the growth and development of ginger plants and increase the yield of ginger. The content of soluble sugars in ginger was the highest in T2;the content of vitamin C in ginger was the highest in treatment T1( 15-15-15);treatment T2 showed the highest content of free amino acids in ginger;the content of proteins in ginger treated by T3( 22-8-10) was the highest;T3 also showed the highest content of gingerol;and treatment T2 had the lowest nitrate content. Comprehensive from the growth,yield and quality effect of ginger plants,treatment T2 was the best. [Conclusions]This study provides scientific basis for the rational fertilization and high-yield and efficient cultivation of ginger.

Effects of Organic Compound Fertilizers on Soil Water Infiltration Characteristics

In order to study the effects of organic compound fertilizers on soil water infiltration characteristics,an indoor one-dimensional soil column water infiltration test was carried out.Six soil sample treatment groups were set,namely marshy solonchak(control check,CK for short),bamboo charcoal-mixed marshy solonchak,Difuyuan-mixed marshy solonchak,salined flavo-aquic soil(CK),bamboo charcoal-mixed salined flavo-aquic soil and Difuyuan-mixed salined flavo-aquic soil.After 120 min of infiltration,compared with the CK groups of marshy solonchak and salined flavo-aquic soil,the cumulative infiltration volumes of the bamboo charcoal and difuyuan treatment groups increased by -18.78%,-3.93% and 25.77%,6.53%,respectively;and the displacement increased by -18.93%,1.64% and 22.6%,12.5%,respectively.The relationship between the wetting front displacement and time conformed to a linear function.The effects of organic compound fertilizers on the initial infiltration rates of marshy solonchak and salined flavo-aquic soil were significant,and the relationship between infiltration rate and time conformed to a power function.The vertical distribution of soil moisture under the application of organic compound fertilizers showed that the moisture content changed relatively small within 5 cm of the surface soil layer,then decreased slowly within 5-10 cm of the soil layer,and decreased drastically below 10 cm of soil layer;and relative to the CK group,the application of organic compound fertilizers was beneficial to increase the moisture content of salined flavo-aquic soil.The organic compound fertilizers reduced the water infiltration capacity of marshy solonchak and improved the water infiltration capacity of salined flavo-aquic soil.Compared with Difuyuan,bamboo charcoal reduced the water infiltration capacity of marshy solonchak better and improved the water permeability of salined flavo-aquic soil more significantly.

Application of Aisi Si/TE Compound Bacterial Fertilizer in Rice

[Objectives]To investigate the application effect of compound microbial fertilizer on crops.[Methods]Livestock and poultry breeding waste,rapeseed cake and peanut straw were fully decomposed,and then added with compound functional microbial inoculum to produce Aisi Si/TE(active chelated silicon/trace element)compound microbial fertilizer,which was used to conduct 10%nitrogen reduction alternative fertilization experiment on rice.[Results]The yield of rice applied with 225 kg/ha Aisi Si/TE compound bacterial fertilizer was 7203 kg/ha,increased by 5.4%,6.9%and 46.9%,respectively compared to those of rice applied with 225 kg/ha inactivated Aisi Si/TE compound microbial fertilizer,conventional fertilization and blank control(P<0.01).Application of Aisi Si/TE compound microbial fertilizer to rice improved soil organic matter and effective nutrient content and showed obvious effect of saving nitrogen and increasing yield and income.In addition,it provided a good micro-ecological environment,passivated and solidified heavy metals,effectively reduced the biological mobility of heavy metals,and greatly reduced the cadmium content in rice.[Conclusions]Application of Aisi Si/TE compound microbial fertilizer is beneficial to improving the quality of agricultural products.

Highly-Effective Nitrogen-phosphate Compound Fertilizer.

The Tianji brand highly effective nitrogen-phosphate compound fertilizer is produced by the Shanxi Cheyenne Fertilizer Plant, one of the main compound fertilizer producers in the country. The fertilizer is made through the chemical reaction between the nitric acid and the fine phosphate ore and a series of purifying and condensing processes. It contains nitrogen, phosphate, calcium, magnesium, zinc, copper and iron. It has high and lasting fertility

Production of bio-fertilizer from Ascophyllum nodosum and Sargassum muticum (Phaeophyceae)

Oceans and seas form a large body of water that contains a natural biodiversity.For humans,represents a resource,which makes this a point of interest,from researches to improve the economy.Seaweeds produce many compounds and secondary metabolites that can be used in different fi elds of industry such as food,agricultural,pharmaceutical and health.Even though seaweeds are ancestral resources,recently it was notorious a global interest in knowing more about its potentials,where biotechnology plays an important role in research.Studies showed that seaweed has many bioactive compounds benefi cial to plant development,giving them a great potential as an agricultural fertilizer.Adding seaweeds to the soil provides organic matter,minerals,trace elements,growth plant regulator,metabolites,vitamins,and amino acids and it can work as a soil conditioner.In Portugal,the use of seaweeds for agriculture is important since long time ago.In the past,populations that lived near coastal zone depended on the seaweeds as a family subsistence but,throughout the years,synthetic fertilizers replaced seaweeds.Our work aimed to assess the potential of the extracts obtained from Ascophyllum nodosum and from Sargassum muticum as an agricultural fertilizer.This evaluation was carried out with rice plants(Oryza sativa)and lettuce(Lactuca sativa),in germination bioassays,the culture of rice and lettuce plants in pots,and culture of lettuce plants in hydroponics.For that,seaweed liquid extracts were used in different concentrations in different bioassays.Results show that extracts obtained from two seaweeds,A.nodosum and S.muticum,can be promissory plant biofertilizer at a concentration of 25% and had a positive effect on seed germination,plant development,and production.

Iron Fertilization with Enhanced Phytoplankton Productivity under Minimal Sulfur Compounds and Grazing Control Analysis in HNLC Region

The present study investigated quantitatively the significance of HNLC (high-nutrient low-chlorophyll) regions and its grazing control with the improved iron fertilization for climate change. The limitation of iron (Fe) for phytoplankton growth in HNLC regions was confirmed by sulfur compounds (S) such as volcanic ash and hydrogen sulfide (H2S) in batch cultures, whose chemical sediment of Fe3S4 showed 4.06 wt%. The technologies developed for iron fertilization since 1993 till now were not practical to provide sufficient amounts of bioavailable iron due to sedimentary iron sulfides induced by undersea volcanic sulfur compounds. The proposed technology for iron fertilization was improved to enhance the bioavailable iron to phytoplankton by keeping minimal sulfur compounds in HNLC regions. The low productivity of phytoplankton by grazing control in HNLC regions was 6% diatoms whose 52% was grazed by copepods and 42% by krill on the basis of data analysis in 2000 EisenEx Experiment at boundary of Antarctic and African tectonic plates. All of the previous iron fertilization experiments were conducted at volcanic sulfur compounds enriched HNLC regions. The present study revealed that the enhanced phytoplankton productivity in batch culture without sedimentary iron sulfides can be possible only if sulfur compounds are minimal, as is in Shag Rocks (53°S, 42°W) of South Georgia in Scotia Sea in the Southern Ocean.

MIMO Soft-sensor Model of Nutrient Content for Compound Fertil- izer Based on Hybrid Modeling Technique

In compound fertilizer production,several quality variables need to be monitored and controlled simul- taneously.It is very difficult to measure these variables on-line by existing instruments and sensors.So,soft-sensor technique becomes an indispensable method to implement real-time quality control.In this article,a new model of multi-inputs multi-outputs(MIMO)soft-sensor,which is constructed based on hybrid modeling technique,is pro- posed for these interactional variables.Data-driven modeling method and simplified first principle modeling method are combined in this model.Data-driven modeling method based on limited memory partial least squares (LM-PLS)algorithm is used to build soft-senor models for some secondary variables;then,the simplified first prin- ciple model is used to compute three primary variables on line.The proposed model has been used in practical process;the results indicate that the proposed model is precise and efficient,and it is possible to realize on line quality control for compound fertilizer process.

The bio-interactions between plants,insecticides and fertilizers:an innovative approach for the research of xenobiotic substances

In this experiment carried out on Caribbean chili pepper plants(Capsicum chinensis),the bio-insecticide azadirachtin in combination with an NPK fertilizer proved to have a greater lethal impact on the larvae of Aedes albopictus than each substance on its own.This synergistic effect is noticeably important when both inputs are sprayed directly on the leaves of the plant(foliar application).While the plants treated with azadirachtin or NPK alone cause a 33.6%and 36.4%mortal-ity respectively of the Ae.albopictus larvae,the combination of the two inputs induces a 74.4%mortality on the mosquito larvae.To account for this synergistic effect phenomenon inside the plant,the azadirachtin+NPK combination most likely interacts with the capsaicinoid compounds naturally produced by the plant.Not only does this study carried out on azadirachtin reveal major results but the methodology itself offers a most interesting approach on how to boost the agricultural inputs within the plants.As a matter of fact,this research axis demands developing since the control of pests harmful to men has been dramatically lacking insecticide molecules acting on new targets over the past three decades.

Complex Fertilizer Production from the Residue in Producing FurfuralUsing Straw: Study on the Additives and Reaction Conditions

The complex additives which contain (ω) 4%(6% phosphoric acid, 4%(6% calcium triple superphosphate, 80%(90% calcium phosphate, 2%(3% calcium carbonate, 2%(4% sodium hydrosuphite, 2%(4% ferric sulfate and 2%(4% aluminum sulfate were used to produce furfural by straw hydrolysis with sulfuric acid. The effect of reaction conditions on residue acidity and furfural productivity were investigated. The experimental results showed that the suitable conditions are sulfuric acid concentration 16% (ω), the added sulfuric acid amounting to 6% of all raw materials, the weight ratio of liquid to solid 2:1, the content of additives in straw 6%, temperature 100(130oC and reaction time of 2 h, under which the productivity of furfural was 9.6% of rice straw and 10.5% of wheat straw respectively(or 80%(85% of the theoretical value), meanwhile the residue became a compound fertilizer.

基于离散元法的潮湿甘蔗复合肥参数标定

为能准确建立潮湿甘蔗复合肥的离散元模型,合理设置仿真参数,提高肥料颗粒动力学仿真结果的准确性,以休止角为响应值,对不同含水率的甘蔗复合肥进行试验研究。通过卸料仓法建立含水率与休止角的三元回归方程,决定系数为0.99;基于Hertz-Mindlin with JKR粘结模型,通过Plackett-Burman试验、爬坡试验和Box-Behnken试验从9个初始参数筛选出JKR表面能、甘蔗复合肥剪切模量、甘蔗复合肥与不锈钢静摩擦系数、甘蔗复合肥间静摩擦系数、甘蔗复合肥间恢复系数5项显著性参数,并建立休止角—离散元参数模型,模型P值小于0.01,变异系数为6.35%;最后,通过对不同含水率下的最佳参数组合进行仿真休止角试验,仿真结果与物理休止角试验的相对误差小于7.66%,验证不同含水率的甘蔗复合肥参数标定结果和研究方法是合理可靠的。研究结果可为基于离散元法的甘蔗施肥机械动力学仿真研究提供参考。

化肥配施复合微生物肥对大豆养分积累及产量和品质的影响

为了明确东北北部地区复合微生物肥对大豆生长及产量和品质的影响,于2021和2022两年选用金源55(P1)及克山1号(P2)作为供试大豆品种,设置常规施肥CK(T1)、50%氮肥+复合微生物肥(T2)、无氮肥+复合微生物肥(T3)共3个处理。对比研究不同施肥处理对大豆不同时期干物质量、养分积累量及产量的影响。结果表明:与T1处理相比,T2处理提高了大豆对氮、磷、钾的养分吸收量,两个品种中都以T2处理养分利用效率最高。复合微生物肥替代化肥处理(T2、T3)使大豆的蛋白质品质有显著提升,但对大豆脂肪含量有明显抑制效果,其中T1处理脂肪含量显著高于T2和T3处理。2021年,在金源55(P1)中,T2处理大豆产量较T1提高了13.02%,T3处理大豆产量较T1降低了9.34%。在克山1号(P2)中,T2处理大豆产量较T1提高了5.34%,T3处理大豆产量较T1降低了9.26%。2022年,金源55(P1)T2处理大豆产量较T1提高了12.60%,T3处理大豆产量较T1降低了17.23%。克山1号(P2)T2处理大豆产量较T1提高了20.43%,T3处理大豆产量较T1降低了11.41%。综上所述,两年试验表明,大豆产量与品种选用相关性较低,与施肥梯度相关性较高,大豆产量大小取决于复合微生物肥的施用量,在低量复合微生物肥施用条件下,化肥作用比较显著,反之化肥作用下降。本研究为大豆种植中复合微生物肥合理使用提供理论依据。

有机无机复混肥料对水稻产量及养分吸收利用的影响

为了提高水稻肥料利用率,减少化肥施用量,研究有机无机复混肥的施用效果,设置不施肥(CK)、常规施肥(普通复合肥,氮肥分次施用)(FFP)、等养分有机无机复混肥(一次性施肥)(T1)、等养分有机无机复混肥(氮肥分次施用)(T2)、90%养分有机无机复混肥(氮肥分次施用)(T3)、80%养分有机无机复混肥(氮肥分次施用)(T4)共6个处理,研究有机、无机肥配施对水稻产量及氮磷吸收利用的影响。各处理花后干物质积累量对籽粒贡献率(62.7%~68.5%)均高于干物质转运量对籽粒贡献率(31.5%~37.3%);各处理的实际产量表现为T2>T1>FFP>T3>T4>CK,与FFP处理相比,T2和T1处理增产6.6%和2.2%,T3和FFP处理产量无显著差异;成熟期各处理水稻植株地上部氮素和磷素吸收积累量在籽粒部分占比达到65%和70%以上,与FFP处理相比,T1处理氮磷肥吸收利用率、氮磷肥农学利用率和氮磷肥偏生产力分别增加了8.9%和12.9%、0.9%和3.2%、0.9和3.2 kg·kg^(-1),T2处理氮磷肥吸收利用率、氮磷肥农学利用率和氮磷肥偏生产力分别增加了1.6%和1.6%、2.6%和9.6%、2.6和9.6 kg·kg^(-1),T3和T4处理与FFP处理差异不显著。有机、无机肥配施能提高氮磷养分吸收利用率,在氮磷钾总养分相同的情况下,一次性施用有机无机复混肥更有利于提高水稻氮磷吸收,在氮肥分次施用情况下,有机无机复混肥增产效果更明显,适当减肥不会降低水稻产量,还可以减少稻田养分残留。

不同种类锌肥在农业生产上的应用效果评价

锌是作物不可或缺的微量营养元素之一,严重缺锌会影响作物的生长,进而导致人体锌营养摄入不足,危害人体健康。施用锌肥是改善土壤缺锌和补充作物锌营养的有效方式,对作物产量和品质的提升也有显著效果。概述了单质锌肥(无机锌肥、螯合锌肥、络合锌肥、纳米锌肥)和含锌复合肥等在农业生产中的应用效果,对影响锌肥大规模应用的原因进行了探讨。指出了锌肥在实际应用中存在的养分退化、利用率低、作用机制不明确等问题,并对锌肥未来的发展进行了展望。