Effects of Organic Fertilizers and a Microbial Inoculant on Leaf Photosynthesis and Fruit Yield and Quality of Tomato Plants

Summary

An experiment was conducted to examine the effects of applications of an organic fertilizer (bokashi), and chicken manure as well as inoculation of a microbial inoculant (commercial name, EM) to bokashi and chicken manure on photosynthesis and fruit yield and quality of tomato plants. EM inoculation to both bokashi and chicken manure increased photosynthesis, fruit yield of tomato plants. Concentrations of sugars and organic acids were higher in fruit of plants fertilized with bokashi than in fruit of other treatments. Vitamin C concentration was higher in fruit from chicken manure and bokashi plots than in those from chemical fertilizer plots. EM inoculation increased vitamin C concentration in fruit from all fertilization treatments. It is concluded that both fruit quality and yield could be significantly increased by EM inoculation to the organic fertilizers and application directly to the soil.     

Properties and Applications of an Organic Fertilizer Inoculated with Effective Microorganisms

Summary

Research studies were conducted to elucidate the chemical, physical and microbiological properties of an organic fertilizer that was inoculated and fermented with a microbial inoculant (Effective Microorganisms or EM). The quality estimation methods employed addressed the mechanistic basis for beneficial effects of soil improvement and crop yield. Effective Microorganisms or EM was utilized as the microbial inoculant that is a mixed culture of beneficial microorganisms. Tests showed that the fermented organic fertilizer contained large populations of propagated Lactobacillus spp. Actinomycetes, photo-synthetic bacteria and yeasts; high concentrations of intermediate compounds such as organic acids and amino acids; 0.1% of mineral nitrogen mainly in the ammonium (NH₄ ⁺) form, and 1.0% of available phosphorus; and a C:N ratio of 10. The quality of the fermented organic fertilizer depends on the initial water content; addition of molasses as a carbon and energy source; and the microbial inoculant. The medium pH appears to be reliable fermentation quality criterion for producing this organic fertilizer. Beneficial effects of the fermented organic fertilizer on soil fertility and crop growth will likely depend upon the organic fraction, direct effects of the introduced microorganisms, and indirect effects of microbially-synthesized metabolites (e.g., phytohormones and growth regulators).     

Response of soybean plants to two inoculation methods with arbuscular mycorrhizal fungus of Glomus sp. strain R-10 under field condition

ABSTRACT

Inoculation of arbuscular mycorrhizal (AM) fungi has a great potential to reduce input of phosphorus fertilizer. In this study, we tested the hypothesis that transplanting of pre-inoculated plants (pre-inoculation) with AM fungal inoculum Glomus sp. strain R-10 (R-10) is more effective for increasing AM fungal colonization and soybean yield than placing R-10 inoculum into field soil (direct inoculation). We cultivated pre-inoculated and direct inoculated plants with and without R-10 in the same field. On the contrary to the hypothesis, hyphal colonization was increased by direct inoculation, but decreased by pre-inoculation in an early growth stage. Shoot phosphorus concentration, shoot dry weight, and yield also showed the same trend as the hyphal colonization. These results indicated that pre-inoculation with R-10 would be less effective for increasing AM fungal colonization and yield than direct inoculation. It may be due to a colonization strategy of R-10 and short duration for establishment of seedling.     

长期施肥对黑垆土氨化细菌数量和氨化作用强度的影响

为探讨长期施肥下黑垆土氨化作用的变化,在长期定位试验条件下,分析了长期施肥对黑垆土氨化细菌数量和氨化作用强度的影响。结果表明,在小麦连作下,各施肥处理均可不同程度提高土壤中氨化细菌数量和氨化作用强度,其中单施有机肥及有机无机肥配施的效果更明显。在不同施肥处理中,氮磷配施有机肥处理的土壤氨化细菌数量最多(7.53×108个·g~(-1)),是不施肥处理(CK)的189.2倍,氨化作用强度最高(1.49mg·kg~(-1)),较CK增加55.0%;其次为单施有机肥、氮肥配施有机肥和磷肥配施有机肥处理,其氨化细菌数量和氨化作用强度均显著高于CK。在苜蓿连作下,与CK相比,单施磷肥处理的土壤氨化细菌数量和氨化作用强度均明显降低,降幅分别为99.5%和49.7%。因此,黄土高原黑垆土区小麦连作时,长期施用有机肥及有机无机肥配施均可提高土壤有机氮的转化作用,增强其供氮能力;苜蓿连作时,长期单施磷肥可减弱土壤有机氮的转化作用。     

Effect of Organic Fertilizer and Effective Microorganisms on Growth,Yield and Quality of Paddy-Rice Varieties

Summary

The effect of an organic fertilizer inoculated with Effective Microorganisms (EM) on the growth, yield and quality of 13 paddy-rice varieties varying with maturation period was studied. EM inoculation increased kernel enlargement after the panicle formation stage and also increased ear number and length and kernel number. The yield of brown rice from EM inoculation was higher for the standard fertilizer rate and lower for the higher rate of organic fertilizer. EM inoculation increased the glutinousness and the total quality index of glutinous rice varieties. Under 1993 weather conditions, early and medium-ripening non-glutinous varieties and glutinous varieties were suitable for nature farming with EM-inoculated organic fertilizer.     

Effect of fertilization on crop responses and solute transport for rice crop in a sub-humid and sub-tropical region

In order to increase the efficacy of water and control the losses of fertilizer, it is necessary to assess the influence of level of fertilization on crop responses, movement and balance of water and solutes from fertilizers in the root zone. With this goal, the reported study was undertaken to determine the effect of fertilization on crop responses and fertilizer solute transport in rice crop field in a sub-humid and sub-tropical region. Field experiment was conducted on rice crop (cultivar IR 36) during the years 2003, 2004, and 2005. The experiment included four fertilizer treatments comprising different levels of fertilizer application. The fertilizer treatments during the experiment were: F₁ = control with N:P₂O₅:K₂O as 0:0:0 kg ha^?1; F₂ = fertilizer application of N:P₂O₅:K₂O as 80:40:40 kg ha^?1; F₃ = fertilizer application of N:P₂O₅:K₂O as 120:60:60 kg ha^?1 and F₄ = fertilizer application of N:P₂O₅:K₂O as 160:80:80 kg ha^?1. The results of the investigation revealed that the magnitudes of crop parameters such as grain yield, straw yield, and maximum leaf area index increased with increase in fertilizer application rate. The levels of fertilization had very little effect on water loss via deep percolation and water use by the crop. The levels of fertilization had considerable effect on N leaching loss and uptake of N whereas it had no significant impact on leaching loss of water-soluble phosphorus. This indicated that PO₄-P leaching loss was very low in the soil solution as compared to nitrogen due to fixation of phosphorus in soils. The results also revealed that increase in level of fertilization increased water use efficiency considerably by increased crop yield. From the observed data of nutrient use efficiency, crop yield and environmental pollution, the fertilization rate of N:P₂O₅:K₂O as 80:40:40 kg ha^?1 (F₂) was the most suitable fertilizer treatment for rice crop among studied treatments.     

Effects of a Microbial Inoculant and Organic Fertilizers on the Growth,Photosynthesis and Yield of Sweet Corn

Summary

A microbial inoculant known as Effective Microorganisms or EM is a mixed culture of naturally-occurring, beneficial microorganisms (predominantly lactic acid bacteria, yeast, actinomycetes, photosynthetic bacteria and certain fungi) that has been used with considerable success to improve soil quality and the growth and yield of crops, particularly in nature farming and organic farming systems. Despite this success, the exact mechanisms of how this EM elicits such beneficial effects is largely unknown. Consequently, a study was conducted to determine the effects of EM and organic fertilizer on the growth, photosynthesis, and yield of sweet corn (Zea mays L.) under glasshouse conditions, compared with chemical fertilizer. An organic fertilizer consisting of a mixture of oilseed mill sludge, rice husk and bran, and fish processing waste, was inoculated and fermented with EM as the microbial inoculant. The organic fertilizer and chemical fertilizer were then applied to respective pots to compare the growth, yield and physiological response of sweet corn plants. EM applied with the organic fertilizer was shown to promote root growth and activity, and to enhance photosynthetic efficiency and capacity, which resulted in increased grain yield. This was attributed largely to a higher level of nutrient availability facilitated by EM application over time. Interestingly, during the early stage of the experiment, the growth and dry matter yield of plants that received organic fertilizer were actually lower than those treated with chemical fertilizer that provided higher initial levels of macronutrients. However, during the intermediate and late growth stages, EM increased the nutrient availability of the organic fertilizer to a higher level, than the chemical fertilizer. Consequently, even though there was an early lower growth rate for plants that received EM-fermented organic fertilizer compared with chemical fertilizer, the final biomass and grain yield from organic fertilizer was equal to or higher than from chemical fertilizer.     

AMF接种与根系分隔对红壤上间作玉米生长及磷素吸收的影响

通过盆栽模拟试验研究比较以Glomus mosseae(GM)和Glomus etunicatum(GE)为接种剂,设置不同根系分隔方式(不分隔,隔尼龙网,隔塑料膜)对间作玉米植株生长及磷素吸收累积的影响。结果表明,两种菌根真菌GM和GE对玉米根系的侵染效果相近,GM为玉米优势丛枝菌根真菌(AMF),接种GM使玉米根长、地上部和根系生物量、地上部和根系磷含量、磷吸收量均显著提高;接种GE显著降低了玉米根冠比、株高和根系磷吸收效率。间作体系不同根系分隔方式对玉米的影响也不同,根系隔尼龙网处理显著降低了玉米根长和根系生物量,显著提高了根系的磷含量;根系隔塑料膜处理对玉米的地上部和根系磷含量、磷吸收量以及根系磷吸收效率均起显著降低作用。所有复合处理中,以GM不分隔处理组合对间作玉米的生长及磷素累积的促进作用最好。     

Suppression of Botryosphaeria canker of apple by arbuscular mycorrhizal fungi

Stem brown canker or Botryosphaeria canker disease impairs the growth and kills the shoots, limbs and even trunks of infected apple trees. Apple roots are usually colonized by arbuscular mycorrhizal fungi, which may have a positive influence on plant growth and suppression of diseases. In order to assess the efficacy of AM to suppress the disease severity and plant growth enhancement, nine AMF inoculation treatments (Sclerocystis dussi, Glomus intraradices, G. fasciculatum, G. bagyaraji, G. leptotichum, G. monosporum, Gigaspora margarita, a mixed AM culture and a non-mycorrhizal control treatment) were used in this present study. Two-year-old potted apple plants, maintained under glasshouse conditions, were either pre-inoculated with AMF followed by stem inoculation with Botryosphaeria ribis or simultaneously inoculated with Botryosphaeria ribis and AM. The results indicated that the incidence of canker was less severe in plants inoculated with AMF in comparison to non-mycorrhizal control. Timing of inoculation also had a significant effect on disease development and plant survival. Plants pre-inoculated with mycorrhiza performed better over those inoculated simultaneously with Botryosphaeria ribis and AM fungi. Furthermore, AM inoculation resulted in improved survival and growth of AMF-colonized plants; though, it varied by species of AM fungi utilized.     

Comparative effects of food processing liquid slurry and inorganic fertilizers on tanner grass (Brachiaria arrecta) pasture: grass yield,crude protein and P levels and residual soil N and P

This small‐plot field study evaluated food processing liquid slurry (FPLS) as a potential fertilizer for tanner grass (Brachiaria arrecta) production on an acidic loam soil. The treatments, arranged in a randomized complete block design with three replicates, consisted of an unfertilized control, inorganic fertilizer applied at 50 and 200 kg nitrogen (N) ha^?1 with and without phosphorus (P) at 50 kg P ha^?1, and FPLS applied at 50 and 200 kg N ha^?1. Compared to the unfertilized control, the FPLS applied at 200 kg N ha^?1 significantly increased grass dry‐matter yield (DMY), herbage crude protein (CP) and P content, and N and P uptake in the second of two trials and P uptake in both trials. However, DMY and contents, of CP and P were generally lower for the FPLS treatments compared to the inorganic fertilizers. Apparent N recovery was higher for the inorganic fertilizer treatments than FPLS treatments in trial 1, while apparent P recovery was similar among all treatments in both trials. The FPLS treatments did not significantly increase soil NO₃‐N and P concentrations, but increased NH₄‐N in the 0–15 cm layer. The results suggest that application of FPLS to tanner grass pastures is an alternative to its disposal in landfill.     

水分胁迫下丛枝菌根真菌对澳洲坚果幼苗磷利用效率的影响

基于云南热区澳洲坚果种植区季节性干旱及先天性低有效磷的土壤特征,探讨丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)接种对具有排根的引种作物-澳洲坚果幼苗磷利用的影响,为外来物种的本地驯化栽培提供理论依据。在正常水分与水分胁迫条件下,对盆栽的澳洲坚果幼苗分别接种土著丛枝菌根真菌(native arbuscular mycorrhizal fungi)和摩西球囊霉(Glomus mosseae),测定接种不同AMF对澳洲坚果幼苗生长、菌根定殖、酸性磷酸酶活性、柠檬酸分泌及磷素吸收等的影响。结果表明,接种土著AMF(N-AM)处理对澳洲坚果幼苗排根或非排根的侵染率显著高于接种摩西球囊霉(G-AM)处理,正常水分条件下N-AM处理的侵染率最高;两种水分条件下,接种AMF的植株地上部和地下部干重更高,正常水分处理下达到最大。菌根侵染率与排根产生量之间显著正相关,水分胁迫显著抑制了植株的排根产生量;与不接种相比,接种处理能显著提高排根产生量。接种AMF后根系对磷素的活化、吸收及转化能力显著升高,表现为接种的澳洲坚果幼苗根系、茎秆和叶片中全磷含量较高,两种水分条件下均表现为N-AM>G-AM>CK;菌根与排根相互协调共同发挥作用,显著改善了澳洲坚果幼苗根系对磷素的活化和吸收能力,且菌根比排根发挥了更大作用,尤其在水分胁迫条件下。两种AMF均能与澳洲坚果幼苗建立共生关系,N-AM处理的幼苗各指标显著优于G-AM处理,可能是由于拥有多样性优势的土著AMF在澳洲坚果幼苗根系中定殖能力较强或是AMF真菌对外来物种澳洲坚果有正反馈作用。     

不同种类磷肥对果蔗的有效性研究

通过室内盆栽试验,以不施磷作为对照,分别选用钙镁磷肥、聚磷酸铵和磷酸一铵进行施磷处理,研究施用不同类型磷肥对黑皮果蔗生物量、根系形态及磷吸收特性的影响。结果显示,施磷处理能够显著促进果蔗生长,与未施磷处理的相比较,钙镁磷肥、聚磷酸铵和磷酸一铵处理的果蔗地上部生物量分别增加了67.00%、58.38%、50.65%。在同一施磷水平下,钙镁磷肥处理的果蔗生物量显著高于聚磷酸铵和磷酸一铵处理。在不同类型磷肥处理下,果蔗的根系形态特征有显著差异。钙镁磷肥处理的果蔗根系总根长和总根系表面积均比其他两种磷肥处理有显著增加;钙镁磷肥和聚磷酸铵处理的果蔗根平均直径和根总体积之间无显著差异。不同类型磷肥处理下,果蔗地上部和根系的磷含量无显著差异;但钙镁磷肥处理的果蔗磷积累量显著高于磷酸一铵处理。     

Light and plant growth‐promoting rhizobacteria effects on Brachiaria brizantha growth and phenotypic plasticity to shade

This is the first report on the effect of light intensity and plant growth‐promoting rhizobacteria (PGPR) on the growth of a tropical forage grass, being a relevant study to improve pasture management in conventional farming and integrated crop‐livestock‐forestry systems. In this study, our aim was to evaluate the effects of light intensity and Burkholderia pyrrocinia and Pseudomonas fluorescens inoculation on Brachiaria brizantha cv. BRS Piatã growth, and phenotypic plasticity to shade. The experiment was conducted in a semi‐controlled environment. Seedlings of B. brizantha were allocated to full sun and shade. P. fluorescens and B. pyrrocinia were inoculated individually or co‐inoculated by soil drench, 14 days after seedling emergence. We evaluated morphogenesis, structural and growth parameters. Irrespective of the light regime, co‐inoculated plants had greater leaf area and SPAD index (chlorophyll content). Increase in total biomass production in co‐inoculated plants was over 100% and 300%, under full sun and shade respectively. Co‐inoculated P. fluorescens and B. pyrrocinia increased shade tolerance in B. brizantha, improving plant performance. Co‐inoculation promoted growth in B. brizantha under both sun and shade, indicating its potential as a bio‐fertilizer in conventional and integrated systems, especially in silvopastoral systems, where light availability to pasture growth may be limited.     

Nitrogen efficiency in long-term wheat–maize cropping systems under diverse field sites in China

Efficiency of fertilizer N is becoming increasingly important in modern agricultural production owing to increasing food requirement and growing concern about environments. However, there is almost no study regarding its long-term efficiency in wheat and maize cropping systems. Long-term (15 years) experiments involving wheat (Triticum aestivum L.) and maize (Zea mays L.) rotations at five field sites with various soil and climate characteristics in China were used to determine the nitrogen (N) efficiency, including the physiological efficiency, recovery efficiency and N mass balance of soil–plant systems in response to different fertilization treatments. The present study consisted of nine treatments: unfertilized, N, phosphorus, potassium, straw and manure or their combinations. The contribution of N fertilizers to wheat yield was higher than to maize and suggested that wheat could be given priority over maize when determining N application rates. Uptake of 1 kg N produced 35.6 kg of wheat grain and 39.5 kg of maize grain. The deficit of N in soils without applied N ranged from 40 to 103 kg N ha⁻¹ year⁻¹, while N surpluses in soils with applied N fertilizers ranged from 35 to 350 kg N ha⁻¹ year⁻¹. The apparent accumulated N recovery efficiency (NRE_ac) varied widely from 4% to 90%: unbalanced fertilization and other soil limiting factors (such as aluminium toxicity) were associated with low NRE_ac. In the treatments of combination of N, phosphorus and potassium with normal application rates, the average of NRE_ac in four out of five sites reached 80%, which suggested that best management of N fertilizers could recover most of N fertilizers applied to soils. The results will be helpful to understand the long-term fate of N fertilizers and to optimize the N fertilization for agricultural practices and environment protection.     

长期隔年施磷对陇东旱塬作物产量和土壤肥力的影响

为探讨不同施肥方式对旱地土壤的培肥作用及增产效果,以1979-2019年在甘肃省陇东旱塬黑垆上土进行的长期定位施肥试验为基础,研究了不施肥料(CK)、单施氮肥(N)、氮磷肥配施(NP)、秸秆还田+氮磷肥配施(磷肥为隔年施用,施磷年份该处理记为SNP,不施磷年份记为SN)4种措施对作物产量、产量稳定性和可持续性以及土壤综合肥力的影响。结果表明,长期隔年施磷(SN)的春玉米和冬小麦产量分别较CK增加151.4%和159.2%,较长期施磷处理(SNP)增加8.6%和6.9%;SN的春玉米产量稳定性和可持续性均低于N和NP处理,而冬小麦产量稳定性和可持续性均优于N和NP处理;SN处理显著提高了耕层土壤综合肥力(IFI),其耕层土壤IFI值分别较CK、N和NP处理高25.5%、21.3%和6.1%,年际间变异强度高于CK和N处理。说明,在陇东旱塬黑垆土春玉米-冬小麦轮作体系下,采用秸秆还田+氮磷配施隔年施磷技术,既在减少50%化学磷肥投入的情况下仍能保证作物产量稳定和持续,并能有效提高耕层土壤综合肥力。     

Population dynamics of arthropods in a sunn-hemp zucchini interplanting system

Zucchini, Cucurbita pepo L., is often colonized by economically important insect pests such as the striped (Acalymma vittatum Fab.) and spotted (Diabrotica undecimpunctata howardi Barber) cucumber beetles. To evaluate the impact of an interplanted cover crop on arthropods associated with zucchini, field experiments were conducted in which sunn hemp (Crotalaria juncea L.) was interplanted with zucchini as a living mulch and compared with zucchini monoculture (bare-ground) during 2009, 2010 and 2011 growing seasons. The experiment consisted also of two types of fertilizer usage including the application of synthetic or organic fertilizer in the form of chicken manure. Foliar counts of arthropods conducted on zucchini plants showed significantly lower numbers of the striped cucumber beetle in sunn hemp interplanted plots compared to bare-ground treatment plots. Also, fewer spotted cucumber beetles were found on zucchini plants in sunn hemp plots. Aphid abundances were variable during the study and significantly lower in sunn hemp treatment plots at one study site in 2009. Among predators, spiders were significantly more abundant in sunn hemp treatment plots during 2009. Fertilizer type did not have a significant effect on arthropod numbers on zucchini plants. Potential causes of arthropod population differences among the two treatments are discussed.     

Yield and Nitrogen Use of Irrigated Processing Potato in Response to Placement,Timing and Source of Nitrogen Fertilizer in Manitoba

Optimizing nitrogen (N) fertilizer management in irrigated potato (Solanum tuberosum L.) on coarse-textured soils is challenging. The “4R” nutrient stewardship framework of using N fertilizer at the right rate, right source, right placement and right time provides approaches to improve fertilizer use efficiency while maintaining or improving yield. This 3-years replicated field plot study evaluated effects from a series of N fertilization strategies including 10 combinations of sources, placement and timing, as well as fertigation, on irrigated processing potato (cv. Russet Burbank) grown for a total of five site-years in the Province of Manitoba, Canada. Treatments were designed to provide early to late availability of N to the potato crop. Nitrogen was applied to 80% of Provincial N recommendation to increase the likelihood of observing improved fertilizer use efficiency and effects of treatments on yields. Measurements were tuber yield, size distribution, specific gravity, hollow-heart rate, fertilizer apparent N recovery (ANR) and agronomic nitrogen use efficiency (NUE). Results showed differences in yield, quality, ANR and NUE between fertilizer treatments were generally very small or absent. Average tuber marketable yields for fertilizer treatments were significantly greater than those for the unfertilized control (P?<?0.001). Split application of urea at planting and hilling, and urea at planting with fertigation occasionally increased tuber marketable yields on sites of coarse textured soils (P?<?0.05). Use of polymer-coated urea (ESN) or stabilized urea with inhibitors (SuperU) did not affect yield, quality or N use of potato. Site-year difference (P?<?0.001) were apparent for all measures highlighting the importance of soil and climatic conditions on agronomic and environmental effects of N management practices. The results indicate current grower practice of split urea application at planting and hilling and urea at planting following by in-season fertigation are sound. Results indicate growers could shift to the more convenient practice of ESN at planting without reducing yields. Absence of treatment effects suggests N was generally not a limiting factor for the current study, indicating that the current recommendation for potato production in Manitoba over-estimate site-specific crop N needs.     

Phosphorus efficiency in long-term (15 years) wheat–maize cropping systems with various soil and climate conditions

Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate phosphorus (P) fertilizer utilization efficiency, including the physiological efficiency, recovery efficiency and the mass (the input–output) balance, at five sites across different soil types and climate zones in China. The five treatments used were control, N, NP, NK and NPK, representing various combinations of N, P and K fertilizer applications. Phosphorus fertilization increased average crop yield over 15 years and the increases were greater with wheat (206%) than maize (85%) across all five sites. The wheat yield also significantly increased over time for the NPK treatments at two sites (Xinjiang and Shanxi), but decreased at one site (Hunan). The P content in wheat was less than 3.00 g kg⁻¹ (and 2.10 g kg⁻¹ for maize) for the N and NK treatments with higher values for the Control, NP and NPK treatments. To produce 1 t of grain, crops require 4.2 kg P for wheat and 3.1 kg P for maize. The P physiological use efficiency was 214 kg grain kg⁻¹ P for wheat and 240 kg grain kg⁻¹ P for maize with over 62% of the P from P fertilizer. Applying P fertilizer at 60–80 kg P ha⁻¹ year⁻¹ could maintain 3–4 t ha⁻¹ yields for wheat and 5–6 t ha⁻¹ yields for maize for the five study sites across China. The P recovery efficiency and fertilizer use efficiency averaged 47% and 29%, respectively. For every 100 kg P ha⁻¹ year⁻¹ P surplus (amount of fertilizer applied in excess of crop removal), Olsen-P in soil was increased by 3.4 mg P kg⁻¹. Our study suggests that in order to achieve higher crop yields, the long-term P input–output balance, soil P supplying capacity and yield targets should be considered when making P fertilizer recommendations and developing strategies for intensively managed wheat–maize cropping systems.     

协同作物提质增效和土壤地力提升的最佳氮素有机替代比例探索——以攀枝花芒果为例

晚熟芒果是攀枝花市重要的支柱产业,但近年由于生产中重化肥轻有机肥,导致果园质量退化,酸化现象严重、芒果品质下降。在前期研究和调研的基础上,根据攀枝花晚熟芒果及果园土壤的特点,选择了低、中、高3个肥力等级的芒果园,通过两年田间试验探索了晚熟芒果在不同氮素有机替代比例及优化施肥技术的作物产量、品质及土壤地力提升效果。结果表明：1）总体来说,当氮素有机替代比例为40%时,所有果园芒果产量和果实品质最佳,产量和氮肥偏生产力显著高于传统、氮磷钾优化及100%全量替代处理,Vc含量显著高于其他处理。而替代比例为100%时,低肥力和高肥力果园产量显著下降,氮肥偏生产力显著低于其他替代比例处理,同时会导致土壤磷养分的过量累积。2）随着替代比例的升高,土壤有机质含量增加,土壤pH增加。通过主成分分析得出,各处理的土壤地力水平,随着有机替代的比例增加而逐渐增加,替代比例为100%时,综合得分最高,其次是部分替代处理,传统施肥和优化施肥处理低于有机替代处理。3）综合作物产量、品质及土壤地力,不同土壤肥力下最佳的有机替代比例不同,低肥力和高肥力土壤短期内有机替代比例不宜较高,否则产量显著下降。通过芒果的产量、品质、土壤地力水平等因素综合分析,攀枝花晚熟‘凯特'芒果最优氮素有机替代比例为40%,替代比例过低无法有效提高土壤地力并改善作物品质,而替代比例过高容易导致养分供给不足,作物减产,特别是在土壤养分含量及有机质较低的低肥力果园,由于土壤保肥能力低,须在增施有机肥的同时保证充足的无机养分供应,着重碳氮协同优化。     

不同施肥配比对芒果园土壤养分、微生物数量和酶活性的影响

通过小区试验,探索化肥减施和有机肥替代部分化肥对芒果园土壤养分、微生物数量和酶活性的影响。结果显示,土壤pH值、有机质、碱解氮、速效钾、有速效磷含量顺序均为：常规施肥＞化肥减施20%＞有机肥替代20%,但化肥减施20%和常规施肥处理差异均不显著,有机肥替代20%处理的有机质、速效钾、速效磷均显著低于常规施肥;脲酶、过氧化氢酶、酸性磷酸单酯酶活性顺序为：常规施肥＞化肥减施20%＞有机肥替代20%,化肥减施20%处理土壤酶活性均与常规施肥处理无差异显著性,有机肥替代20%处理的土壤酶活性均显著低于常规施肥;真菌、放线菌数量顺序为：化肥减施20%＞常规施肥＞有机肥替代20%,差异不显著;细菌数量顺序为：有机肥替代20%＞常规施肥＞化肥减施20%,差异不显著;相关性分析结果表明,土壤脲酶、过氧化氢酶、酸性磷酸单酯酶活性均与土壤有机质、碱解氮、速效钾、速效磷有显著或极显著相关性。