利用Illumina高通量测序对复合重金属污染下根际和非根际稻田土壤细菌的研究

There is an increasing concern about rice (Oryza sativa L.) soil microbiomes under the influence of mixed heavy metal contamination.We used the high-throughput Illumina MiSeq sequencing approach to explore the bacterial diversity and community composition of soils in four paddy fields,exhibiting four degrees of mixed heavy metal (Cd,Pb and Zn) pollution,and examined the effects of these metals on the bacterial communities.Our results showed that up to 2 104 to 4 359 bacterial operational taxonomic units (OTUs) were found in the bulk and rhizosphere soils of the paddy fields,with the dominant bacterial phyla (greater than 1％ of the overall community) including Proteobacteria,Actinobacteria,Firmicutes,Acidobacteria,Gemmatimonadetes,Chloroflexi,Bacteroidetes and Nitrospirae.A number of rare and candidate bacterial groups were also detected,and Saprospirales,HOC36,SC-I-84 and Anaerospora were rarely detected in rice paddy soils.Venn diagram analysis showed that 174 bacterial OTUs were shared among the bulk soils with four pollution degrees.Rice rhizosphere soils displayed higher bacterial diversity indices (ACE and Chao 1) and more unique OTUs than bulk soils.Total Cd and Zn in the soils were significantly negatively correlated with ACE and Chao 1,respectively,and the Mantel test suggested that total Pb,total Zn,pH,total nitrogen and total phosphorus significantly affected the community structure.Overall,these results provided baseline data for the bacterial communities in bulk and rhizosphere soils of paddy fields contaminated with mixed heavy metals.     

中国北方森林坡向对土壤细菌和从枝菌根真菌群落的影响

The effects of slope aspects on soil biogeochemical properties and plant communities in forested environments have been studied extensively; however, slope aspect influence on soil microbial communities remains largely unexamined, despite the central role of soil biota in ecosystem functioning. In this study, the communities of both soil bacteria and arbuscular mycorrhizal fungi (AMF) were investigated using tagged pyrosequencing for three types of slope aspects (south-facing aspect, north-facing aspect and flat area) in a boreal forest of the Greater Khingan Mountains, China. The bacterial and AMF community composition differed with slope aspects. Bacterial diversity was the lowest on the north-facing aspect, and AMF diversity was the lowest on the flat area. Aspects also had a significant impact on soil pH and available phosphorus (P) and shrubby biomass. Soil pH and understory shrub biomass were significantly correlated with bacterial communities, and soil available P and shrub biomass showed significant correlations with AMF communities. Our results suggested that slope aspects affected bacterial and AMF communities, mediated by aspect-induced changes in plant community and soil chemical properties (e.g., pH and available P), which improved the knowledge on the effects of forest slope aspects on aboveground and belowground communities.     

长期施用化肥和有机肥对太湖地区水稻土有机碳特征的影响

A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region,China.Of the fourteen randomly distributed treatments consisting of different combinations of organic manure,inorganic nitrogen (N),phosphorus (P),and potassium (K),and rice straw,eight were selected for the present study in 2007.Application of organic manure plus straw significantly increased soil organic carbon (SOC) content of the topsoil (0-10 cm) compared to that of chemical fertilizers alone.The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments.The stable carbon isotope ratio (δ 13 C) ranged from 24‰ to 28‰ and increased gradually with depth.The content of SOC was significantly (P < 0.05) negatively correlated with δ 13 C.In the 0-20 cm layer,the δ 13 C value significantly decreased in the treatments of manure alone (M),manure and chemical N and P fertilizers (MNP),manure and chemical N,P,and K fertilizers (MNPK),manure,rice straw,and chemical N fertilizer (MRN),and chemical N fertilizer and rice straw (CNR),as compared with the no-fertilizer control.In the 30-50 cm layer,however,the ratio significantly increased in all the treatments except Treatment CNR.Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks,being faster in the manure treatments than the chemical fertilizer treatments.The average rate of mineralization varied from 55.36 to 75.46 mL CO 2 kg-1 d-1 and that of stable mineralization from 10 to 20 mL CO 2 kg-1 d-1.In eight weeks of incubation,cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments,being the highest in Treatment MRN.Combined humus in the soil was mainly (over 50%) composed of tightly combined fraction.The loosely combined humus and its ratio of humic acid (HA) to fulvic acid (FA) significantly increased with long-term application of organic manure and chemical fertilizers.It could be concluded that the cycle of organic C in the paddy soil ecosystem studied was stable over the long-term application of fertilizers and continued cultivation.     

不同施肥管理对红壤性水稻土有机碳、氮形态的影响

A long-term experiment beginning in 1981 in Jinxian County of Jiangxi Province, subtropical China, was conducted in a paddy field under a double rice cropping system with four different fertilization regimes, including 1) no fertilizer as control (CK), 2) balanced chemical N, P, and K fertilizers (NPK), 3) organic manure using milk vetch and pig manure in the early and late rice growing season, respectively (OM), and 4) balanced chemical fertilizers combined with organic manure (NPKM). Samples (0-17 cm) of the paddy field soil, which was derived from Quaternary red clay, were collected after the late rice harvest in November 2003 for determination of total organic carbon (TOC) and total nitrogen (TN) and fractions of organic C and N. Results showed that TOC and TN in the NPKM and OM treatments were significantly higher than those in other two treatments (CK and NPK). Application of organic manure with or without chemical fertilizers significantly increased the contents of all fractions of organic C and N, whereas chemical fertilizer application only increased the contents of occluded particulate organic C (oPOC) and amino acid N. In addition, application of organic manure significantly enhanced the proportions of free particulate organic carbon (fPOC) and oPOC in total C, and those of amino sugar N and amino acid N (P < 0.01) in total N. In contrast, chemical fertilizer application only increased the proportions of oPOC and amino acid N (P < 0.05). There were no significant differences in either contents or proportions of soil organic C and organic N fractions between the NPKM and OM treatments. These indicated that organic manure application with or without chemical fertilizers played the most significant role in enhancing soil organic C and N quantity and quality in the paddy field studied.     

生物炭对水稻土Fe(Ⅲ)还原过程中碳源利用效率的影响

研究以采自吉林和江西的水稻土为供试土壤,采用恒温泥浆厌氧培养方法,探讨添加生物炭和不同有机碳源(葡萄糖、乙酸钠、丙酮酸钠和乳酸钠)条件下土壤泥浆中Fe(Ⅱ)浓度和pH值的变化,采用Logistic模型对Fe(Ⅲ)的还原特征进行了拟合分析。结果表明,添加生物炭可以促进2种水稻土中的Fe(Ⅲ)还原能力。添加生物炭条件下,不同外源有机碳对水稻土中Fe(Ⅲ)还原特征的影响存在差异,在吉林水稻土中,对Fe(Ⅲ)还原的调控能力显著大于江西水稻土。2种水稻土均能较好地利用乳酸盐、丙酮酸盐和葡萄糖还原Fe(Ⅲ),而添加乙酸盐后的Fe(Ⅲ)还原则表现出一定的滞后性。添加乳酸盐处理最大Fe(Ⅲ)还原速率高于其他有机碳源,且达到最大Fe(Ⅲ)还原速率的时间最短,表明乳酸盐是2种水稻土中铁还原过程的优势碳源。添加发酵性的有机碳源可显著影响泥浆培养过程中的pH值,有机碳源对江西水稻土pH的影响明显大于吉林水稻土,表明吉林水稻土中有机碳源对发酵过程产生的氢的利用能力优于江西水稻土。     

淹水培养时间对水稻土中Fe（Ⅲ）异化还原能力的影响

为了模拟水稻土淹水过程,探讨不同淹水培养时间水稻土中铁还原微生物群落利用不同碳源的活性变化特征,以接种不同淹水时期的浙江水稻土浸提液作为微生物群落来源,以人工合成的Fe（OH）3为惟一的电子受体,不同碳源作为惟一电子供体,在30℃恒温条件下厌氧培养,定期测定Fe（Ⅱ）含量和pH值变化,采用Logistic模型进行动力学分析。研究结果表明,葡萄糖作为电子供体时,不同淹水时期的微生物群落总体上对Fe（OH）3还原反应有较快的响应;丙酮酸盐作为碳源时,铁还原反应启动的时间整体迟于葡萄糖,Fe（Ⅱ）累积量在反应30d才表现出显著累积并逐渐趋于稳定;淹水20d的微生物群落能最先利用乳酸盐还原Fe（Ⅲ）,反应15 d的Fe（Ⅱ）累积量达到601.60 mg.L^-1;淹水30 d的铁还原微生物群落对乙酸盐的利用能力增强,最大Fe（Ⅱ）累计量升高到538.47 mg.L^-1,Fe（Ⅲ）还原率达到75.81%。不同淹水时期利用各种碳源的体系pH表现为葡萄糖从中性下降至酸性,丙酮酸盐和乳酸盐中性偏酸,乙酸盐的pH略微偏碱,不同淹水时期出现的水稻土微生物群落结构不同是导致Fe（OH）3还原能力不同的主要原因。不同的碳源利用可以指示不同的铁还原微生物群落变化：淹水培养早期的铁还原微生物群落对葡萄糖和丙酮酸盐的利用较为迅速和显著,同一时期出现的微生物群落不能以乙酸盐作为电子供体;淹水培养后期的铁还原微生物群落以乳酸盐和乙酸盐为优势碳源来还原Fe（OH）3。     

光照对水稻土中氧化铁还原的影响

选择不同地区的水稻土样品,采用泥浆厌氧恒温培育方法,在避光和光照条件下,测定了培养过程中土壤泥浆的Fe(Ⅱ)浓度及叶绿素a含量的变化。结果表明:光合微生物的产氧作用是影响水稻土中铁还原的主要原因,而光照对铁还原微生物没有直接影响;光合微生物仅在某些水稻土中大量繁殖,其叶绿素a含量随着光照时间延长由逐渐增加到趋于稳定。通过微生物镜检和光谱分析发现,由天津和四川水稻土中分离的光合微生物主要是念珠蓝细菌(Nostocsp.)和鱼腥蓝细菌(Anabaenasp.),其吸收光谱曲线均具有664 nm的叶绿素a吸收峰,表明其具有利用光合系统Ⅱ进行产氧光合作用的特征。在厌氧培养过程中Fe(Ⅱ)浓度与土壤中叶绿素a含量变化有着明显的负相关关系。     

有机物-金属相互作用对重金属负载土柱中粘土矿物吸附剂再生的影响

Natural clay minerals can play an important role in crude remediation of wastewater polluted with the heavy metals (HMs) Cu,Zn and Ni.The presence and timing of addition of natural dissolved organic matter (DOM) have a significant effect on the HM removal by clay mineral sorbents.However,the influence of the presence of DOM on the remediation of the used clay mineral sorbents once saturated with HMs is largely unknown.To resolve this,clay mineral-rich soil column of varying composition,loaded (i) with Cu,Zn and Ni only,(ii) first with DOM followed by Cu,Zn and Ni,or (iii) with DOM,Cu,Zn and Ni simultaneously,was used in a set of desorption experiments.The soil columns were leached with 0.001 mol L-1 CaCl2 dissolved in water as control eluent and 0.001 mol L-1 CaCl2 dissolved in DOM as treatment eluent.During the preceding loading phase of the sorbent,the timing of DOM addition (sequential or concurrent with HMs) was found to have a significant influence on the subsequent removal of the HMs.In particular when the column was loaded with DOM and HMs simultaneously,largely irreversible co-precipitation took place.Our results indicate that the regeneration potential of clay mineral sorbents in wastewater treatment will be significantly reduced when the treated water is rich in DOM.In contrast,in manured agricultural fields (where HMs enter together with DOM),HM mobility will be lower than expected from interaction dynamics of HMs and clay minerals.     

不同有机物添加方式下水稻对干旱胁迫的响应

采用室内土培试验,研究了在不同有机质(半腐解水稻秸秆和腐熟猪粪)表施和混施添加模式下,水稻生长和主要抗旱生理生化指标对干旱胁迫的响应.结果表明:①干旱胁迫下水稻株高降低、分蘖数减少,根系则表现出主根伸长、支根增多、根表面积和根体积增加;秸秆表施和猪粪混施可明显改善水稻的生长和根系形态,而秸秆混施和猪粪表施的改善作用不显著;②干旱胁迫下叶片叶绿素含量显著降低,超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)活性均显著下降,秸秆表施和猪粪混施能够在一定程度上抑制这种下降幅度.     

盐分对土壤呼吸和有机质动力学的影响与土壤电导率相关，而与渗透势的关系更为密切

Osmotic potential (OP) of soil solution may be a more appropriate parameter than electrical conductivity (EC) to evaluate the effect of salts on plant growth and soil biomass.However,this has not been examined in detail with respect to microbial activity and dissolved organic matter in soils with different texture.This study evaluated the effect of salinity and sodicity on respiration and dissolved organic matter dynamics in salt-affected soils with different texture.Four non-saline and non-sodic soils differing in texture (S-4,S-13,S-24 and S-40 with 4％,13％,24％ and 40％ clay,respectively) were leached using combinations of 1 mol L-1 NaC1 and 1 mol L-1 CaC12 stock solutions,resulting in EC (1:5 soil:water ratio) between 0.4 and 5.0 dS m-1 with two levels of sodicity (sodium absorption ratio (SAR) ＜ 3 (non-sodic) and 20 (sodic),1:5 soil:water ratio).Adjusting the water content to levels optimal for microbial activity,which differed among the soils,resulted in four ranges of OP in all the soils:from-0.06 to--0.24 (controls,without salt added),-0.55 to-0.92,-1.25 to-1.62 and-2.77 to-3.00 Mpa.Finely ground mature wheat straw (20 g kg-1) was added to stimulate microbial activity.At a given EC,cumulative soil respiration was lower in the lighter-textured soils (S-4 and S-13) than in the heavier-textured soils (S-24 and S-40).Cumulative soil respiration decreased with decreasing OP to a similar extent in all the soils,with a greater decrease on Day 40 than on Day 10.Cumulative soil respiration was greater at SAR =20 than at SAR ＜ 3 only at the OP levels between-0.62 and-1.62 MPa on Day 40.In all the soils and at both sampling times,concentrations of dissolved organic C and N were higher at the lowest OP levels (from-2.74 to-3.0 MPa) than in the controls (from-0.06 to-0.24 MPa).Thus,OP is a better parameter than EC to evaluate the effect of salinity on dissolved organic matter and microbial activity in different textured soils.     

Changes in proteolytic bacteria in paddy soils in response to organic management

Proteolytic bacterial communities, which mineralize organic nitrogen, play a key role in agricultural systems. In this study, alkaline metalloprotease (apr) gene fragments from proteolytic bacteria were investigated in bulk and rhizosphere paddy soil from four fields under organic management (for 2, 3, 5, and 9 years), and from one field under conventional management (for 2 years). We analyzed the abundance and structure of the proteolytic bacterial communities using real-time quantitative PCR and denaturing gradient gel electrophoresis. Our results showed that the abundance of proteolytic bacteria ranged from 1.57?×?10⁸ to 8.02?×?10⁸?copies/g of soil. In addition, the abundance of the proteolytic bacteria in the paddy soils under organic management was significantly higher than those in the paddy soil under conventional management. Moreover, the gene copy numbers in the rhizosphere soils were significantly higher than those in the bulk soils. The abundance of proteolytic bacteria tended to increase with the duration of organic management, with the highest abundance being found in the soil that had been under organic management for 5 years. However, the proteolytic bacteria communities in the paddy soils were not significantly affected by management practices. Phylogeny analysis showed that all gel bands obtained represented genes from Pseudomonas. Additionally, correlation analysis and canonical correspondence analysis showed that C/N, C, and N were important factors that influenced the abundance and community structure of the proteolytic bacteria. These results suggest that proteolytic bacteria are indicators in organic management systems, depolymerize organic N and hence maintain soil sustainability.

Abbreviations: CM: conventional management; OM: organic management; DGGE: denaturing gradient gel electrophoresis; qPCR: real-time quantitative PCR detecting system; COFCC: China organic food certification center; CCA: canonical correspondence analysis     

紫色水稻土轻组有机质的季节动态研究

以位于重庆市北碚区西南大学试验农场(30°26′N,106°26′E)的紫色水稻土为研究对象,利用重液(NaI,密度1.8 g·cm-3)对土壤中轻组组分进行提取,对土壤中轻组有机质在整个油菜生长季的季节变化情况进行分析与讨论。结果表明:表层(0~30 cm)土壤轻组物质(LF)的含量为2.95%~5.51%,平均值为4.38%;土壤轻组有机碳含量(LFOC)和轻组氮含量(LFN)的变化范围分别为1.44~3.72 g·kg-1和0.08~0.17 g·kg-1,其平均值分别为2.79 g·kg-1和0.14 g·kg-1。LFOC具有明显的季节变化(P<0.05),其含量在油菜生长中期最高,其次是生长后期,而在生长初期最低;LFN的季节变化趋势与LFOC一致,但季节差异性不显著(P>0.05)。轻组有机碳分配比例(LFOC/SOC)的变化范围为9.21%~24.47%,具有明显的季节变化(P<0.05),其变化趋势与LFOC的季节变化一致;而轻组氮的分配比例(LFN/TN)变化范围为4.55%~12.58%,无明显的季节变化。轻组C/N比值季节变化范围为18.52~25.04,平均值为20.66,全土C/N比值的变化范围为9.04~14.36,平均值为11.66,说明轻组有机质的生物可利用性较土壤总有机质高。相关分析表明,轻组有机碳、氮含量分别与根系生物量、根系碳含量、根系氮含量呈极显著(P<0.01)或显著(P<0.05)正相关;回归分析表明,土壤轻组有机碳、氮含量变化的40%~60%可由根系生物量、根系碳氮含量决定,说明根系是调控紫色水稻土轻组有机碳、氮季节变化的主要生态因子。     

长期定位试验条件下的水稻田土壤有机质含量变化研究

依托湖北武汉、重庆北碚、湖南望城、湖南祁阳、江西南昌、浙江杭州6个水稻土壤肥力长期定位试验历史样品及数据,分析和讨论了土壤有机质含量变化趋势及对施化肥和有机肥的响应差异。施有机肥提升土壤有机质含量显著高于施化肥的效果。施化肥NPK处理,6个试验点土壤有机质含量都呈现提升趋势;但是,有机质平均年增量、有机质累计增量与累计有机肥施用量的比值都是逐年下降的,固定施肥方法提高土壤有机质含量是有限的,最高达到平衡点,施化肥的有机质含量的平衡点低于施有机肥的,土壤有机质含量提升不仅对施有机肥有响应,而且与累积产量也有一定的相关关系。     

热辐射对水稻土有机质组成的影响

本文研究了受不同程度热辐射后的水稻土中有机质组分的变化情况,结果表明:随温度升高,土壤中水溶性有机碳(DOC)含量先增加后减少,200℃变化尤为显著,增加为CK的3.68 ～ 7.45倍,中性糖、糖醛酸与DOC的变化趋势一致.辐射温度不同,土壤中的胡敏酸、富里酸组成和含量亦发生不同程度的变化,300℃胡/富比值最大(1.79 ～ 5.04),土壤腐殖质聚合程度增加;200℃胡敏酸的E4/E6比值最大,反映此温度下土壤芳香缩合度低、具有较多的脂族结构物质、土壤腐殖化程度低.     

Community structure of bacteria and fungi responsible for rice straw decomposition in a paddy field estimated by PCR-RFLP analysis

Rice straw including leaf sheaths and blades put in nylon mesh bags was placed in the plow layer of a Japanese paddy field after harvest under upland conditions and after transplanting of rice seedlings under flooded conditions. In addition, rice straw that was decomposed under the upland conditions during the off-crop season in winter was placed again in soil at the time of transplanting. The materials were collected periodically to analyze the community structure of the bacteria and fungi responsible for rice straw decomposition by PCR-RFLP analysis. The PCR products with 27f and 1492r primers designed for bacterial 16S rDNA and with EF3 and EF4 primers designed for fungal 18S rDNA were digested with four restriction endonucleases (Hinf I, Sau3A I, Hae III, EeoR I). Bacterial communities in the decomposing rice straw were different from each other between upland and flooded conditions, between leaf sheaths and blades, and between straw samples with and without decomposition under upland conditions during the off-crop season. Fungal communities in the decomposing rice straw were also different between the leaf sheaths and blades under upland soil conditions. Score plots of bacterial and fungal communities in the principal component analysis were separated from the plot of the straw materials along with the duration of the placement, indicating the succession of bacterial and fungal communities in decomposing rice straw with time.     

配施有机肥对潜育化水稻土的培肥效果

为探索潜育化水稻土的培肥措施,通过田间试验研究了有机无机肥配施对潜育化低产水稻土产量和土壤养分有效性的影响。结果显示:连续2季施用有机肥后,潜育化水稻土产量显著提高,以早稻配施紫云英-晚稻配施猪粪处理的产量最高。添加有机肥降低了潜育化水稻土耕层土壤p H值。早稻配施紫云英,晚稻配施猪粪处理的有机质提高明显,比NPK处理提高了15.22%;早稻配施紫云英,晚稻配施猪粪处理的潜育化水稻土全氮含量比单施化肥处理提高4.19%;早稻配施紫云英,晚稻单施化肥处理的潜育化水稻土有效磷含量提高最多,比NPK处理提高了4.92%;相比于NPK处理,早稻配施紫云英,晚稻单施化肥处理的土壤速效钾含量比两季均单施化肥处理提高了13.2%。因此,潜育化水稻土适当配施有机肥可以提高土壤养分有效性,增加水稻产量,可以作为培肥改良潜育化水稻土的参考方法。     

有机物料碳和土壤有机碳对水稻土甲烷排放的影响

基于30年水稻土长期施肥定位试验,在保证原有定位试验正常开展的前提下,将部分化肥处理变更为有机肥处理(或反之),通过观测一年水稻轮作周期内不同处理甲烷(CH_4)排放通量季节性变化,探讨不同肥力水稻土中外源有机碳及土壤有机碳含量对田间CH_4排放的影响。结果表明:施化肥处理和有机肥处理,水稻土全年CH_4累积排放量范围分别为1.73~4.72和35.09~86.60 g·m~(-2)。有机肥处理改施化肥后,田间土壤CH_4的排放量显著降低;化肥处理改施有机肥或有机肥处理增施有机肥后,田间土壤CH_4的排放量显著提高。外源有机碳的输入量是田间土壤CH_4年排放量的决定性因素,外源有机碳输入量(x)与水稻土CH_4年累积排放量(y)之间满足直线方程:y=0.087 7 x+3.265 7(R~2=0.965 9,n=21)。土壤有机碳同样也是影响稻田CH_4排放的因素,在不同有机碳水平的水稻土上施用等量相同化肥或有机肥,土壤有机碳含量高的水稻土都更有利于CH_4的产生。单施化肥稻田土壤CH_4排放的最主要碳源是土壤有机碳,有机碳含量(x)和水稻土CH_4年累积排放量(y)之间的指数方程:y=0.162 4 e~(0.162 2 x)(R~2=0.940 6,n=9)。有机肥可促进土壤有机碳分解释放CH_4,土壤有机碳含量相同的条件下,高量有机肥比常量有机肥的土壤有机碳分解比率高0.65%,等量相同有机肥但土壤有机碳含量不同的条件下,土壤有机碳分解比率无显著差异;同样,土壤有机碳也可促进有机物料碳分解释放CH_4,在常量有机肥或高量有机肥处理中,土壤有机碳含量高者比低者的有机物料碳分解比率分别多出3.57%和2.34%。     

Effects of organic matter application on microbial biomass and available nutrients in various types of paddy soils

Abstract

The effect of the addition of bromacil (pesticide) or/and a sewage sludge on the urease, phosphatase and dehydrogenase activities of soil was studied. Urease and phosphatase activities increased initially with the addition of bromacil. This effect disappeared after 28 d of soil incubation. The increase in the urease and phosphatase activities caused by the addition of sewage sludge was more pronounced than that of bromacil. The combined addition of sewage sludge and bromacil also led to an increase in the activity of both hydrolases. Dehydrogenase activity was affected negatively by the addition of bromacil and positively by the sewage sludge addition. When sewage sludge and bromacil were added simultaneously, dehydrogenase activity was higher than when sewage sludge alone was added.     

有机物料循环对红壤稻田系统有机质积累的贡献研究

中长期定位试验研究有机物料循环再利用对红壤稻田系统土壤有机质积累的贡献结果表明,红壤稻田系统有机物料自然归还量可达6 16 2kg/hm2 ,人为归还量可达13480kg/hm2 ;仅依靠系统内有机物料的自然归还,其土壤有机质亏缺为5 0 %左右,呈下降趋势;系统内可循环再利用的有机物料全部还田,土壤有机质盈余率可达80 %以上;预测结果显示有机物料循环再利用5 0年内可提高土壤有机质19.4～32 .6 g/kg ,增长率达83.6 %～14 0 .5 %