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1.
李江涛  张斌  彭新华  赖涛 《土壤学报》2004,41(6):912-917
土壤颗粒有机物 (POM)是土壤有机碳库中活动性较大的碳库。POM的形成对提高土壤碳库和缓解大气CO2 的升高具有重要意义。POM的形成与土壤团聚体的形成和性质密切相关 ,且深受土地利用和土壤管理的影响。实验土壤采自江西省红壤研究所无机肥长期定位试验地 ,各施肥处理为 :CK(不施肥 )、NPK(施氮磷钾肥 )、NPK(=) (施双倍氮磷钾肥 )和NPK OM(施氮磷钾肥和猪粪处理 )。研究发现 :施肥显著地增加了水稻土POM的含量 ;随着化肥施肥量和有机肥的增加 ,POM含量增加 ,NPK、NPK(=)和NPK OM处理的POM含量比CK分别增加了 1 1~ 1 3倍、1 2~ 1 4倍和 1 5~ 1 9倍 ;施肥也提高了土壤团聚体稳定性 ,表现为NPK OM >NPK(=) >NPK >CK ;各处理POM含量随土壤团聚体粒级的减小而增加 ,其C/N比为降低趋势 ;团聚体稳定性与POM含量呈极显著关系 (r=0 98,p <0 0 1)。研究结果说明施肥导致POM碳库的增加是因为有机物投入的增加以及水稻土大团聚体的形成  相似文献
2.
耕作对土壤有机物和土壤团聚体稳定性的影响   总被引:22,自引:8,他引:14  
Agricultural sustainability relates directly to maintaining or enhancing soil quality. Soil quality studies in Canada during the 1980‘s showed that loss of soil organic matter (SOM) and soil aggregate stability was standard features of non-sustainable land management in agroecosystems. In this study total soil organic carbon (SOC), particulate organic matter (POM), POM-C as a percentage of total SOC, and aggregate stability were determined for three cultivated fields and three adjacent grassland fields to assess the impact of conventional agricultural management on soil quality. POM was investigated using solid-state ^13C nuclear magnetic resonance (NMR) to determine any qualitative differences that may be attributed to cultivation. Results show a highly significant loss in total SOC, POM and aggregate stability in the cultivated fields as compared to the grassland fields and a significant loss of POM-C as a percentage of total SOC.Integrated results of the NMR spectra of the POM show a loss in carbohydrate-C and an increase in aromatic-C in the cultivated fields, which translates to a loss of biological lability in the organic matter. Conventional cultivation decreased the quantity and quality of SOM and caused a loss in aggregate stability resulting in an overall decline in soil quality.  相似文献
3.
中国亚热带红壤团聚体稳定性与土壤化学性质的关系   总被引:14,自引:1,他引:13  
The stability of aggregates in the surface soil is crucial to soil erosion and runoff generation. Thus, to understand the stability and the breakdown mechanisms of soil aggregates as well as the relationship between aggregate stability and selected soil chemical properties, such as different forms of Fe and Al oxides, organic matter, CEC and clay content, the aggregates of slightly and severely eroded red soils derived from Quaternary red clay in subtropical China were analyzed using the routine wet sieving and the Le Bissonnais methods. The results indicated that the aggregates of the severely eroded soils were more stable than those of the slightly eroded soils. Different aggregate breakdown mechanisms resulted in different particle size distribution. The slaking from entrapped air in aggregates severely destroyed the soil aggregates, especially in the slightly eroded soils. Meanwhile, mechanical breakdown and microcracking had little effect on the aggregates compared to slaking. The fragments resulting from slaking were mainly microaggregates that increased in size with increasing clay content. The main fragment size of the slightly eroded soils was 1.0-0.2 mm, while for the severely eroded soils it was 5.0-2.0 mm and 1.0-0.5 mm. Overall, more than 20% of the fragments were smaller than 0.2 mm. In addition, aggregate stability was positively and often significantly correlated with Fed, Ald, Feo and clay content, but significantly and negatively correlated to SOC.  相似文献
4.
长期施用有机肥对旱地红壤团聚体结构与稳定性的影响   总被引:13,自引:0,他引:13  
利用长期定位试验研究了红壤旱地团聚体结构及其稳定性。结果表明:与对照相比,各有机-无机配施处理均可不同程度地降低土壤容重并提高其孔隙度;增施有机肥后,土壤中大于5mm机械稳定性大团聚体增幅达2%~42%;各处理中大于0.25mm水稳性团聚体百分含量为:厩肥>稻草>绿肥>还田>对照。各有机肥处理中土壤中有机质、无定形氧化铁和无定形氧化铝含量较单施化肥处理分别增加了9%~54%、8.5%~21.7%和10.9%~26.8%。统计结果显示,>0.25mm水稳性团聚体含量与土壤有机质含量成极显著正相关(p<0.01);土壤团聚体破坏率与土壤有机质含量成极显著负相关(p<0.01)。在单施化肥的基础上有机肥的施入不仅有利于红壤旱地土壤大团聚体的形成,还有利于改善土壤团聚体结构及其稳定性。  相似文献
5.
Under semiarid Mediterranean climatic conditions, soils typically have low organic matter content and weak structure resulting in low infiltration rates. Aggregate stability is a quality indicator directly related to soil organic matter, which can be redistributed within soil by tillage. Long-term effects (1983–1996) of tillage systems on water stability of pre-wetted and air dried aggregates, soil organic carbon (SOC) stratification and crop production were studied in a Vertic Luvisol with a loam texture. Tillage treatments included conventional tillage (CT), minimum tillage (MT) and zero tillage (ZT) under winter wheat (Triticum aestivum L.) and vetch (Vicia sativa L.) rotation (W–V), and under continuous monoculture of winter wheat or winter barley (Hordeum vulgare L.) (CM). Aggregate stability of soil at a depth of 0–5 cm was much greater when 1–2 mm aggregates were vacuum wetted prior to sieving (83%) than when slaked (6%). However, slaking resulted in tillage effects that were consistent with changes in SOC. Aggregate stability of slaked aggregates was greater under ZT than under CT or MT in both crop rotations (i.e., 11% vs. 3%, respectively).

SOC under ZT tended to accumulate in the surface soil layer (0–5 and 5–10 cm) at the expense of deeper ones. At depths of 10–20 and 20–30 cm no differences in SOC were encountered among tillage systems, but CT exhibited the highest concentration at 30–40 cm depth. Nevertheless, when comparisons were made on mass basis (Mg ha−1), significant differences in stocked SOC were observed at depths of 0–10 and 0–20 cm, where ZT had the highest SOC content in both rotations. The stock of SOC to a depth of 40 cm, averaged across crop rotations, was greater under ZT (43 Mg ha−1) than under CT (41 Mg ha−1) and MT (40 Mg ha−1) although these figures were not significantly different. Likewise, no significant differences were encountered in the stock of SOC to a depth of 40 cm among crop rotations (i.e., 42 Mg ha−1 for W–V vs. 40 Mg ha−1 for CM).

Crop production with wheat–vetch and continuous cereal showed no differences among tillage systems. Yields were strongly limited by the environmental conditions, particularly the amount of rainfall received in the crop growth season and its distribution. Similar yield and improved soil properties under ZT suggests that it is a more sustainable system for the semiarid Mediterranean region of Spain.  相似文献

6.
Microbial-induced soil aggregate stability under different crop rotations   总被引:12,自引:0,他引:12  
 Changes in the quantity and quality of soil organic carbon, and their effect on soil aggregate stability as a result of growing different crops in rotation with wheat, were investigated on a red earth (Oxic Paleustalf) in Wagga Wagga, New South Wales, Australia. After two cycles of the 1 : 1 rotation, while the total organic carbon in the 0–5 cm soil depth was similar (15.1 g/kg), significant differences in water stable aggregation were observed in the order: wheat/lupin=wheat/barley >wheat/canola>wheat/field pea. Using a selective extraction technique, significant differences in the quality (composition) of the soil organic carbon were detected in the soils from the different rotations. Soil from the lupin rotation had the highest salt- and acid-extractable carbon whereas that from the barley rotation had the highest level of hot-water-extractable carbon and microbial biomass carbon. Rather than total carbon or other extractable fractions, the observed differences in aggregate stability were only significantly (P<0.05) related to microbial biomass carbon, which made up only 1.3–1.7% of the total carbon pool. Multiple linear regression analysis indicated that with the exception of salt-extractable carbon, inclusion of any other of the less labile fractions failed to improve the correlation relationship. The labile nature of the microbial biomass carbon therefore accounted for the transient existence of the differences in aggregate stability under different rotation crops. The latter was found to be transient and disappeared at the end of the subsequent wheat crop. Received: 5 November 1998  相似文献
7.
 Land productivity, along with improvement or maintenance of soil health, must be evaluated together to achieve sustainable agricultural practices. Winter wheat-fallow (W-F) has been the prevalent cropping system in the central Great Plains for 60 years where moisture is a limitation to crop production. Alternative cropping systems show that producers can crop more frequently if residue management and minimum tillage are used. The impact of different crops, crop rotations and tillage management practices on soil quality was assessed by measuring aggregate stability and glomalin production by arbuscular mycorrhizal (AM) fungi in soil from cropping trials established in 1990. Crops were wheat (W), corn (C), proso millet (M), and sunflower (S). Rotations sampled were W-F, W-C-M, W-C-M-F, W-C-F, and W-S-F. In the same area as the cropping trials, soils were taken from a perennial grass (crested wheatgrass) and from a buffer area that had been planted to Triticale for the past 2 years but prior to that had been extensively plowed for weed control. We found that aggregate stability and glomalin were linearly correlated (r=0.73, n=54, P<0.001) across all treatments sampled. Highest and lowest aggregate stability and glomalin values were seen in perennial grass and Triticale soils, respectively. Aggregate stability in W-S-F was significantly lower than in the other crop rotations (P≤0.03), while W-C-M had significantly higher glomalin than the other rotations (P<0.05). Differences between crop rotations and the perennial grass indicate that selected comparisons should be studied in greater detail to determine ways to manage AM fungi to increase glomalin and aggregate stability in these soils. Received: 16 March 1999  相似文献
8.
对甘肃景电灌区盐化和有机质对土壤团聚体的稳定性、黏粒的分散性及阿特伯格极限进行了调查研究。研究结果表明该灌区盐化土壤中水溶性盐以钠盐为主,土壤具有钠质现象。随含盐量和交换性钠离子百分率(ESP)的增加土壤团聚体的稳定性显著降低,黏粒的分散性显著增加,阿特伯格极限具有降低的趋势,明确地说明盐化和伴随着的钠质化是土壤结构性能退化的主要原因。随有机质含量的增加,土壤团聚体的稳定性显著增加,黏粒的分散性显著降低,阿特伯格极限显著增加,说明增加有机质含量可以显著改善盐化土壤的结构性能。可以根据如下公式利用有机质含量(OM)和ESP预测团聚体的稳定性:WSAR=19.4 0.98OM-1.43 ESP(R2=0.5741,n=67)。团聚体稳定性、黏粒分散性、流限和塑限互相之间显著相关,说明流限和塑限可以作为反映盐化土壤结构状况的指标。  相似文献
9.
郭菊花  陈小云  刘满强  胡锋  李辉信 《土壤》2007,39(5):787-793
土壤采自江西省红壤研究所历经22年的肥料定位试验地,各施肥处理为:不施肥(CK)、施N肥(N)、施P肥(P)、施K肥(K)、施N、P肥(NP)、施N、K肥(NK)、施N、P、K肥(NPK)、施双倍N、P、K肥(2NPK)、施N、P、K肥和有机肥(NPK OM).研究了不同施肥处理对水稻土团聚体分布的影响以及土壤有机C、N在各级团聚体上赋存的情况.研究结果表明:有机C、N主要分配在2~0.25 mm的大团聚体上,C/N比随着团聚体粒级的减少而降低;水稻土团聚体的形成与有机C(SOC)密切相关,表现出与“层次性“机制相符的现象;施P、K、NK肥和NPK OM显著提高大团聚体的含量和团聚体的稳定性;NPK OM也显著提高土壤有机C、N和各级团聚体上的有机C、N的含量.  相似文献
10.
施用有机肥是提高土壤有机碳(SOC)含量、促进土壤团聚体形成和改善土壤结构的重要措施。本研究旨在探讨长期作物残留和投入有机物料对水稻土团聚体分布及稳定性的影响,分析不同粒级团聚体的固碳特征及其与团聚体形成的相关性,以及土壤和不同粒级团聚体对累积碳投入的响应。长期定位施肥试验始于1986年,设不施肥(CK)、单施化肥(CF)、秸秆化肥混施(RS)、低量粪肥配施化肥(M1)和高量粪肥配施化肥(M2)5个处理。2009年采集0~10 cm土壤样品,测定总土以及大团聚体(LM,2 mm)、较大团聚体(SM,0.25~2 mm)、微团聚体(MA,0.25~0.053 mm)和黏粉粒(SC,0.053 mm)的质量比例及其SOC浓度,并分析闭蓄于SM内部的颗粒有机物(POM)、微团聚体(MA-SM)和黏粉粒(SC-SM)的质量含量和SOC浓度。结果表明,与CK和CF比较,有机肥混施化肥处理(RS、M1和M2)均显著提高了LM和SM的质量比例和平均当量直径(MWD),降低了SC质量含量;两个粪肥配施化肥处理(M1和M2)的效果优于秸秆化肥混施(RS),但是M1和M2间差异不显著;单施化肥则降低了稳定性团聚体的比例。团聚体的SOC浓度没有随粒级增大而增加,各处理均为LM和SM结合的SOC浓度最高,其次为SC,最小为MA。与CK比较,有机肥混施化肥处理均显著提高了各粒级团聚体的SOC浓度。总土SOC的增加主要取决于SM的SOC含量,而MA-SM组分决定了SM固持SOC的能力。总土、LM和SM的SOC含量以及从SM分离出的POM、MA-SM和SC-SM的SOC含量均与累积碳投入量呈显著正相关,但总土分离出的MA和SC的SOC含量对累积碳投入量反应不敏感,表现出碳饱和迹象。因此,尽管长期大量施用有机物料促进了红壤性水稻土大团聚体的形成和团聚体稳定性,增加了其SOC的固持,但有机质可能不是该土壤水稳性团聚体形成的最主要黏结剂。  相似文献
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