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1.
In the North China Plain(NCP), soil deterioration threatens winter wheat(Triticum aestivum L.) production. Although rotary tillage or plowing tillage are two methods commonly used in this region, research characterizing the effects of mixed tillage on soil characteristics and wheat yield has been limited. A fixed-site field trial was carried out during 2011–2016 to examine the impacts of three tillage practices(5-year rotary tillage with maize straw removal(RT); 5-year rotary tillage with maize straw return(RS); and annual RS and with a deep plowing interval of 2 years(RS/DS)) on soil characteristics and root distribution in the plough layer. Straw return significantly decreased soil bulk density, increased soil organic carbon(SOC) storage and SOC content, macro-aggregate proportion(R_(0.25)) and its stability in the plough layer. The RS/DS treatment significantly increased the SOC content, total nitrogen(TN), and root length density(RLD) in the 10–40 cm layer, and enhanced the proportion of RLD in the 20–30 and 30–40 cm layers. In the 20–30 and 30–40 cm layers, an increase in SOC and TN could lead to higher grain production than commensurate increases in the surface layer, resulting in a sustainable increase in grain yield from the RS/DS treatment. Thus, the RS/DS treatment could lead to high productivity of winter wheat by improving soil characteristics and root distribution at the deeper plough layer in the NCP.  相似文献   

2.
为研究秸秆还田旋耕深度对土壤理化性质和酶活性的影响,明确不同秸秆还田深度条件下土壤理化性质与酶活性的关系,在3年（2016—2018年）田间微区定位试验条件下,研究秸秆旋耕还田10 cm（S1D1）、20 cm（S1D2）、30 cm（S1D3）和秸秆移除旋耕10 cm（S2D1）、20 cm（S2D2）、30 cm（S2D3） 6个处理对东北春玉米农田土壤理化性质和酶活性的影响。结果表明：旋耕深度（D）及其与秸秆处理（S）交互作用（S×D）显著影响土壤有机碳（SOC）含量,0~20 cm土层S1D1、S1D2处理SOC含量较S1D3处理高1.2%~16.0%,而20~40 cm土层S2D3处理SOC含量最高。旋耕深度、秸秆处理及两者交互作用对土壤硝态氮（NO3--N）和铵态氮（NH4+-N）含量、蔗糖酶和过氧化氢酶活性影响显著。在0~40 cm土层,D1、D2旋耕深度下秸秆还田处理NO3--N含量比秸秆移除处理平均提高46.9%和34.9%,NH4+-N含量平均降低31.6%和4.4%。在各旋耕深度下,S1处理0~20 cm土层蔗糖酶和脲酶活性高于S2处理,20~30 cm土层过氧化氢酶活性低于S2处理。相关性分析表明,SOC、土壤全氮（TN）与NO3--N、NH4+-N含量和蔗糖酶活性呈显著正相关,与pH、土壤含水量（SWC）呈显著负相关。主成分分析表明,与S1D1相比,S1D2对0~20土层蔗糖酶、脲酶、过氧化氢酶活性和0~40 cm土层SOC、TN含量影响更明显。综上所述,秸秆旋耕还田20 cm可改善0~40 cm土层养分水平,提高土壤酶活性,推荐为东北春玉米产区农田土壤培肥的合理秸秆还田方式。  相似文献   

3.
秸秆还田模式对土壤有机碳及腐植酸含量的影响   总被引：9，自引：2，他引：9  
通过9年水稻-小麦轮作田间定位试验,探讨南方稻麦两熟制农田秸秆还田模式对土壤有机碳(SOC)和腐植酸(HE)的影响。试验设置仅麦秆稻季还田(W)、仅稻秆麦季还田(R)、秸秆稻麦季均还田(RW)和秸秆均不还田(CK)共4个处理。结果表明,秸秆还田显著(P0.05)提高了0~10 cm土层SOC,对土壤总氮(TN)无明显影响;不同秸秆还田模式处理下,0~10 cm土层SOC及TN大小为WRWRCK;10~20 cm SOC及TN大小均为WCKRWR,但各处理之间的差异均不显著。秸秆还田处理中,0~10 cm土层土壤HE、富里酸(FA)和胡敏酸(HA)均低于CK,而在10~20 cm土层则高于CK。不同秸秆还田方式间,0~10 cm土层的HE、FA和HA以W处理为最高,其土壤腐殖化程度最大;而10~20 cm土层则以RW处理为最高,W处理的土壤腐殖化程度最小。相比其他秸秆还田模式,麦秸稻季还田能更好地提高土壤表层有机碳含量和腐殖质品质。  相似文献   

4.
Crop residue retention has been considered a practicable strategy to improve soil organic carbon(SOC) and total nitrogen(TN), but the effectiveness of residue retention might be different under varied tillage practices. To evaluate the effects of residue management on the distribution and stocks of SOC and TN under different tillage practices, a bifactorial experiment with three levels for tillage practices(no-tillage, rotary tillage, and conventional tillage) and two levels for residue managements(residue retention and residue removal) was conducted in the North China Plain(NCP). Results showed that after a short experimental duration(3–4 years), concentrations of SOC and TN in the 0–10 cm layer were higher under no-tillage than under conventional tillage, no matter whether crop residues were retained or not. Residue retention increased SOC and TN concentrations in the upper layers of soil to some degree for all tillage practices, as compared with residue removal, with the greatest increment of SOC concentration occurred in the 0–10 cm layer under rotary tillage, but in the 10–30 cm layer under conventional tillage. The stocks of SOC in the 0–50 cm depth increased from 49.89 Mg ha–1 with residue removal to 53.03 Mg ha–1 with residue retention. However, no-tillage did not increase SOC stock to a depth of 50 cm relative to conventional tillage, and increased only by 5.35% as compared with rotary tillage. Thus, residue retention may contribute more towards SOC sequestration than no-tillage. Furthermore, the combination between residue retention and no-tillage has the greatest advantage in enhancing SOC and TN in the NCP region.  相似文献   

5.
No-tillage (NT) and straw return (S) collectively affect soil organic carbon (SOC). However, changes in the organic carbon pool have been under-investigated. Here, we assessed the quantity and quality of SOC after 11 years of tillage and straw return on the North China Plain. Concentrations of SOC and its labile fractions (particulate organic carbon (POC), potassium permanganate-oxidizable organic carbon (POXC), microbial biomass carbon (MBC), and dissolved organic carbon (DOC)), components of DOC by fluorescence spectroscopy combined with parallel factor analysis (PARAFAC), and the chemical composition of SOC by 13C NMR (nuclear magnetic resonance) spectroscopy were explored. Treatments comprised conventional tillage (CT) and NT under straw removal (S0), return of wheat straw only (S1), or return of both wheat straw and maize residue (S2). Straw return significantly increased the concentrations and stocks of SOC at 0–20 cm depth, but NT stratified them with enrichment at 0–10 cm and a decrease at 10–20 cm compared to CT, especially under S2. Labile C fractions showed similar patterns of variation to that of SOC, with POC and POXC more sensitive to straw return and the former more sensitive to tillage. Six fluorescence components of DOC were identified, mainly comprising humic-like substances with smaller amounts of fulvic acid-like substances and tryptophan. Straw return significantly decreased the fluorescence index (FI) and autochthonous index (BIX) and increased the humification index (HIX). No-tillage generally increased HIX in topsoil but decreased it and increased the FI and BIX below the topsoil. Relative abudance order of the chemical composition of SOC was: O-alkyl C>alkyl-C>aromatic-C>carbonyl-C. Overall, NT under S2 effectively increased SOC and its labile C forms and DOC humification in topsoil and microbially-derived DOC below the topsoil. Return of both wheat and maize straw was a decisive factor in promoting SOC in the plow layer. The stratification of SOC under NT may confer a long-term influence on carbon sequestration.  相似文献   

6.
玉米秸秆颗粒还田对土壤有机碳含量和作物产量的影响   总被引：1，自引：0，他引：1  
为改进麦玉轮作区秸秆还田方式,推进秸秆资源高效利用,快速提升土壤质量,以秸秆不还田为对照（CK）,通过连续3年田间微区试验,研究了等量玉米秸秆粉碎还田（CCSI）和颗粒化还田（GSI）对0~20 cm和20~40 cm土层土壤有机碳（SOC）、可溶性有机碳（DOC）和作物产量的影响。结果表明：与CK相比,GSI和CCSI两种秸秆还田方式均能提高SOC和DOC含量,但主要集中在还田后1.5年内,还田后1.5~3年处理间无显著差异。在秸秆还田处理中,GSI处理能快速提高SOC和DOC含量。在还田当年,GSI处理0~20 cm土层SOC和DOC的平均含量较CCSI处理提高6.59%和3.00%,20~40 cm土层分别提高17.36%和12.65%,且两土层DOC/SOC也显著高于CCSI处理,但随着还田后时间延长,CCSI和GSI处理间差异逐渐缩小,还田后1.5年两者无显著差异。此外,GSI处理利于提高作物产量,且在还田当年增产效应更加突出。与CK和CCSI处理相比,GSI处理还田当年小麦产量分别提高9.80%和10.82%,玉米产量分别提高9.54%和3.45%。进一步分析发现,2013—2016年GSI处理虽然增加了经济投入,但由于具有更高的籽粒产量,最终获得较高的年均净利润,分别比CK和CCSI处理提高10.09%和3.24%。研究表明,秸秆颗粒还田较常规粉碎还田能快速提高SOC和DOC含量,促进当季作物增产,获得较高的经济效益。  相似文献   

7.
The double-rice cropping system is a very important intensive cropping system for food security in China. There have been few studies of the sustainability of yield and accumulation of soil organic carbon(SOC) in the double-rice cropping system following a partial substitution of chemical fertilizer by Chinese milk vetch(Mv). We conducted a 10-year(2008–2017) field experiment in Nan County, South-Central China, to examine the double-rice productivity and SOC accumulation in a paddy soil in response to different fertilization levels and Mv application(22.5 Mg ha~(–1)). Fertilizer and Mv were applied both individually and in combination(sole chemical fertilizers, Mv plus 100, 80, 60, 40, and 0% of the recommended dose of chemical fertilizers, labeled as F100, MF100, MF80, MF60, MF40, and MF0, respectively). It was found that the grain yields of double-rice crop in treatments receiving Mv were reduced when the dose of chemical fertilizer was reduced, while the change in SOC stock displayed a double peak curve. The MF100 produced the highest double-rice yield and SOC stock, with the value higher by 13.5 and 26.8% than that in the F100. However, the grain yields increased in the MF80(by 8.4% compared to the F100), while the SOC stock only increased by 8.4%. Analogous to the change of grain yield, the sustainable yield index(SYI) of double rice were improved significantly in the MF100 and MF80 compared to the F100, while there was a slight increase in the MF60 and MF40. After a certain amount of Mv input(22.5 Mg ha~(–1)), the carbon sequestration rate was affected by the nutrient input due to the stimulation of microbial biomass. Compared with the MF0, the MF100 and MF40 resulted in a dramatically higher carbon sequestration rate(with the value higher by 71.6 and 70.1%),whereas the MF80 induced a lower carbon sequestration rate with the value lower by 70.1% compared to the MF0. Based on the above results we suggested that Mv could partially replace chemical fertilizers(e.g., 40–60%) to improve or maintain the productivity and sustainability of the double-rice cropping system in South-Central China.  相似文献   

8.
稻麦轮作下紫色土有机碳活性及其对长期不同施肥的响应   总被引：7，自引：0，他引：7  
【目的】研究稻麦轮作系统中紫色土总有机碳、活性有机碳和活性有机碳不同组分的变化特征及其对长期不同施肥措施的响应,揭示稻麦轮作系统长期不同施肥管理下有机碳质量和内在组成的变化。【方法】采集22年长期定位试验不施肥(CK)、单施化学氮肥(N)、化肥氮磷钾配施(NPK)、化肥氮磷钾+秸秆还田(NPKS)、高量化肥氮磷钾+等量秸秆还田(1.5NPKS)和化肥氮磷钾+厩肥(NPKM)处理0—20、20—40、40—60 cm土层的土壤,测定了总有机碳、活性有机碳及其不同活性组分的含量,计算土壤碳库管理指数和不同活性组分的分配比例,分析了活性有机碳及其各组分与总有机碳的关系。【结果】长期不同施肥显著影响了各土层总有机碳和活性有机碳含量,与不施肥相比,所有施肥处理均维持或提高了土壤总有机碳、活性有机碳含量和碳库管理指数,其中化肥氮磷钾+秸秆还田(NPKS)处理0—20、20—40和40—60 cm土层总有机碳含量分别提高32.5%、25.7%和5.3%,活性有机碳含量提高37.0%、44.7%和9.3%,碳库管理指数提高38%、49%和9%,其提升幅度高于其他施肥处理。长期不同施肥显著提高了各土层高、中、低活性有机碳含量,有机无机肥配施处理(NPKS、1.5NPKS、NPKM)提升效果高于单施化肥处理(NPK、N);但施肥对各活性组分占活性有机碳比例的影响较小,并没有改变各活性组分的分布格局。土壤活性有机碳及其高、中、低活性组分的含量与土壤深度有关,0—20 cm耕层土壤活性有机碳及高、中、低活性组分的含量均高于20—40和40—60 cm土层。不同土层高、中、低组分占活性有机碳的比例也存在较大差异,0—20 cm土层高、中、低活性组分占活性有机碳的比例平均为23.6%、35.6%和40.7%;下层土壤各活性组分的含量均下降,其中20—40 cm土层低活性组分下降程度较大,导致其占活性有机碳的比例下降至24.7%,而高活性和中活性组分的比例增加至30.5%和44.8%。土壤活性有机碳及其各组分与总有机碳含量呈显著线性正相关,表明土壤活性有机碳可以较好地反映总有机碳变化。【结论】稻麦轮作条件下,长期不同施肥可维持或提高土壤总有机碳、活性有机碳及其不同组分的含量,提高土壤碳库管理指数,氮磷钾肥配合秸秆还田总体提升效果较好,是促进土壤总有机碳和活性有机碳累积、改善土壤有机碳质量的推荐施肥措施。  相似文献   

9.
This study investigated the effects of three contrasting soil management regimes and different nutrient treatments on the distribution of water-stable aggregates(2, 1–2, 0.5–1, 0.25–0.5, and 0.25 mm) and associated soil organic carbon(SOC) and total nitrogen(TN) content in loess soil. A 21-yr long-term experiment was performed, in which soil management regimes include cropland abandonment(Abandonment), bare fallow(Fallow) and wheat-fallow cropping(Cropping). Under Cropping, the following nutrient treatments were employed: control(CK, no nutrient input), nitrogen only(N), nitrogen and potassium(NK), phosphorus and potassium(PK), NP, NPK, and manure(M) plus NPK(MNPK). Results demonstrated that Abandonment significantly increased the content of soil macro-aggregates(0.25 mm) and mean weight diameter(MWD) at 0–10 and 10–20 cm soil horizons compared with Cropping, whereas Fallow yielded lower values of above two parameters. Abandonment increased SOC and TN contents in all aggregate sizes by 17–62% and 6–60%, respectively, at 0–10 cm soil layer compared with Cropping. Conversely, Fallow decreased SOC and TN contents in all aggregates by 7–27% and 7–25%, respectively. Nevertheless, the three soil management regimes presented similar SOC contents in all aggregates at 10–20 cm soil horizon. Only Cropping showed higher TN content in 0.5 mm aggregates than the two other regimes. Consequently, Abandonment enhanced the partitioning proportions of SOC and TN in 1 mm macro-aggregates, and Fallow promoted these proportions in micro-aggregates compared with Cropping. Under Cropping, long-term fertilization did not affect the distribution of aggregates and MWD values compared with those under CK, except for NPK treatment. Fertilizer treatments enhanced SOC and TN contents in aggregates at all tested soil depths. However, fertilization did not affect the partitioning proportions of SOC and TN contents in all aggregates compared with CK. Comprehensive results showed that different soil management regimes generated varied patterns of SOC and TN sequestration in loess soil. Abandonment enhanced soil aggregation and sequestered high amounts of SOC and TN in macro-aggregates. Long-term amendment of organic manure integrated with NPK maintained soil aggregate stability and improved SOC and TN sequestration in all aggregates in loess soil subjected to dryland farming.  相似文献   

10.
Soil bulk density is a basic but important physic soil property related to soil porosity, soil moisture and hydraulic conductivity, which is crucial to soil quality assessment and land use management. In this study, we evaluated the spatial variability of soil bulk density in the 0–20, 20–40, 40–60 and 60–100 cm layers as well as its affecting factors in Southwest China's agricultural intensive area. Results indicated the mean value of surface soil bulk density (0–20 cm) was 1.26 g cm?3, significantly lower than that of subsoil (20–100 cm). No statistical difference existed among the subsoil with a mean soil bulk density of 1.54 g cm?3. Spatially, soil bulk density played a similar spatial pattern in soil profile, whereas obvious differences were found in details. The nugget effects for soil bulk density in the 0–20 and 20–40 cm layers were 27.22 and 27.02% while 12.06 and 3.46% in the 40–60 and 60–100 cm layers, respectively, gradually decreasing in the soil profile, indicating that the spatial variability of soil bulk density above 40 cm was affected by structural and random factors while dominated by structural factors under 40 cm. Soil organic matter was the controlling factor on the spatial variability of soil bulk density in each layer. Land use and elevation were another two dominated factor controlling the spatial variability of soil bulk density in the 0–20 and 40–60 cm layers, respectively. Soil genus was one of the dominated factors controlling the spatial variability of soil bulk below 40 cm.  相似文献   

11.
《农业科学学报》2023,22(7):2221-2232
Fertilization is an effective technique to improve soil fertility and increase crop yield. The long-term effects of different fertilizers on soil considerably vary. Over 38 consecutive years of different fertilization positioning experiments in a double cropping rice field of Qiyang Red Soil Experimental Station, seven different fertilization treatments including CK (no fertilization), NPK (nitrogen, phosphorus, and potassium fertilizer), M (cow manure), NPKM (nitrogen, phosphorus, and potassium with cow manure), NPM (nitrogen and phosphorus with cow manure), NKM (nitrogen and potassium with cow manure), and PKM (phosphorus and potassium with cow manure) were applied to study the effects on rice yield, soil fertility, and nutrient apparent balance in a paddy field. The results showed that the annual average yields of rice in NPKM, NPM, NKM, PKM, M, NPK and CK treatments ranged from 6 214 to 11 562 kg ha–1. Yields under long-term organic and inorganic treatments (NPKM, NPM, NKM and PKM) were 22.58, 15.35, 10.53 and 4.41%, respectively, greater than under the NPK treatment. Soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN) and available potassium (AK) concentration with long-term organic and inorganic treatment (NPKM, NPM, NKM and PKM) were significantly higher than in inorganic fertilizer (NPK) treatments. Soil total phosphorus (TP) and available phosphorus (AP) contentration with organic fertilizer combined with inorganic N and P fertilizer treatment (NPKM, NPM and PKM) were significantly higher than with inorganic fertilizer alone (NPK treatments). The average annual rice yield (11 562 kg ha–1), SOC (20.88 g kg–1), TN (2.30 g kg–1), TP (0.95 g kg–1), TK (22.50 g kg–1) and AP (38.94 mg kg–1) concentrations were the highest in the NPKM treatment. The soil AN concentration (152.40 mg kg–1) and AK contentration (151.00 mg kg–1) were the highest in the NKM treatment. N and P application led to a surplus of nitrogen and phosphorus in the soil, but NPKM treatment effectively reduced the surplus compared with other treatments. Soils under all treatments were deficient in potassium. Correlation analysis showed that SOC, TN, AN, TP, and AP contentration was significantly correlated with rice yield; the correlation coefficients were 0.428, 0.496, 0.518, 0.501, and 0.438, respectively. This study showed that the combined application of N, P, and K with cow manure had important effects on rice yield and soil fertility, but balanced application of N, P, and K with cow manure was required.  相似文献   

12.
Assessing spatial variability and mapping of soil properties constitute important prerequisites for soil and crop management in agricultural areas. To explore the relationship between soil spatial variability and land management, 256 samples were randomly collected at two depths(surface layer 0–20 cm and subsurface layer 20–40 cm) under different land use types and soil parent materials in Yujiang County, Jiangxi Province, a red soil region of China. The pH, soil organic matter(SOM), total nitrogen(TN), cation exchange capacity(CEC), and base saturation(BS) of the soil samples were examined and mapped. The results indicated that soils in Yujiang were acidified, with an average pH of 4.87(4.03–6.46) in the surface layer and 4.99(4.03–6.24) in the subsurface layer. SOM and TN were significantly higher in the surface layer(27.6 and 1.50 g kg~(–1), respectively) than in the subsurface layer(12.1 and 0.70 g kg~(–1), respectively), while both CEC and BS were low(9.0 and 8.0 cmol kg~(–1), 29 and 38% for surface and subsurface layers, respectively). Paddy soil had higher pH(mean 4.99) than upland and forest soils, while soil derived from river alluvial deposits(RAD) had higher pH(mean 5.05) than the other three parent materials in both layers. Geostatistical analysis revealed that the best fit models were exponential for pH and TN, and spherical for BS in both layers, while spherical and Gaussian were the best fitted for SOM and CEC in the surface and subsurface layers. Spatial dependency varied from weak to strong for the different soil properties in both soil layers. The maps produced by selecting the best predictive variables showed that SOM, TN, and CEC had moderate levels in most parts of the study area. This study highlights the importance of site-specific agricultural management and suggests guidelines for appropriate land management decisions.  相似文献   

13.
【目的】为进一步了解秸秆还田对土壤有机碳(SOC)的提升效果,探究作物残体(根系与秸秆)对潮土区SOC的贡献,为华北冬小麦-夏玉米区SOC提升提供理论依据。【方法】基于腐解试验的有机物料碳残留率数据,获得4种有机物料在RothC-26.3模型最优时对应的DPM/RPM参数值(易分解植物残体和难分解植物残体的比值)。利用修订的DPM/RPM参数,获得了改进的RothC-26.3模型,并用郑州潮土区短期腐解试验(2012年11月至2013年11月)和长期定位试验数据(1990—2008年)进行验证,模拟出郑州潮土区冬小麦-夏玉米轮作系统中小麦、玉米残体在3种不同施肥处理下(不施肥CK,平衡施肥NPK和秸秆还田NPKS)对新形成SOC的贡献。【结果】在模型达到最优时,小麦根系(wheat root,WR)、小麦秸秆(wheat straw,WS)、玉米根系(corn root,CR)和玉米秸秆(corn straw,CS)的DPM/RPM值分别为0.89、3.04、4.35和3.25。模型结果显示,CK处理小麦根系、玉米根系的碳投入占碳投入的比例均为50%,而来源于小麦根系、玉米根系的SOC(0—20 cm)占新形成的SOC比例分别为60%、40%;小麦根和玉米根固碳效率分别为15.5%、10.8%;NPK处理小麦根系、玉米根系的碳投入占碳投入的比例分别为60%、40%,而来源于小麦根系、玉米根系的SOC(0—20 cm)占新形成SOC的比例分别为71%、29%;小麦根和玉米根固碳效率分别为17.5%、11.4%;NPKS处理小麦根系、玉米根系、玉米秸秆的碳投入的比例分别为47%、21%、32%,而小麦根系、玉米根系、玉米秸秆对新形成的SOC(0—20 cm)贡献分别为50%、22%、28%;小麦根系、玉米根系、玉米秸秆的固碳效率分别为16.9%、11.2%、11.4%。总之,冬小麦-夏玉米轮作系统中无论是不施肥、平衡施肥还是秸秆还田处理,小麦根系对新形成SOC的贡献率(50%—71%)大于玉米根系和玉米秸秆对新形成SOC贡献率(22%—40%)。源自小麦的SOC占新形成SOC的比例均分别大于源自小麦的碳投入占总碳投入的比例,而源自玉米的投入及其对新形成SOC的贡献则反之。小麦根系的固碳效率(15.5%—17.5%)大于玉米根系和玉米秸秆的固碳效率(10.8%—11.4%)。【结论】改进后的RothC模型可用来探究潮土区冬小麦-夏玉米轮作系统中小麦、玉米残体对新形成SOC的贡献。郑州潮土区冬小麦-夏玉米轮作系统中小麦根系对新形成SOC的贡献率均大于玉米根系和玉米秸秆的贡献率。根茬还田(尤其是小麦根茬还田)更有利于提升土壤有机碳含量。  相似文献   

14.
长期增施有机肥/秸秆还田对土壤氮素淋失风险的影响   总被引：21，自引：2，他引：21  
【目的】研究长期增施有机肥/秸秆还田对作物产量及土壤氮素淋失风险的影响,旨在为华北平原冬小麦-夏玉米轮作区增强土壤肥力、提高作物产量及降低农业面源污染风险提供依据。【方法】以国家褐潮土肥力与肥料效益监测基地的长期肥料试验为平台,研究长达27年不同施肥处理对冬小麦-夏玉米产量、土壤肥力、氮素淋失风险和土壤氮素剖面分布的影响,试验共设置5个施肥处理,即：对照（CK）;氮磷钾（NPK）;氮磷钾+有机肥（NPKM）;氮磷钾+过量有机肥（NPKM+）;氮磷钾+秸秆还田（NPKS）。【结果】（1）在27年的不同施肥处理中,长期增施有机肥/秸秆还田均能使作物增产,改善土壤肥力。其中,增施有机肥处理尤为显著,与NPK相比,NPKM、NPKM+处理提高小麦和玉米产量分别为41%-50%和30%-32%;增加0-20 cm表层土壤有机碳（SOC）和全氮（TN）含量分别为62%-121%、107%-187%;但降低小麦、玉米氮肥偏生产力（PFPN）分别达22%-32%、27%-41%。而NPKS处理对作物增产及提升土壤肥力的作用低于增施有机肥处理,对小麦产量、玉米产量、SOC、TN含量的增幅分别为24%、6%、9%、97%,但提高小麦季PFPN为216%、降低玉米季PFPN为40%。（2）长期增施有机肥/秸秆还田处理中,0-20 cm表层土壤SOC、TN、硝态氮（NO3--N）、可溶性碳氮等养分含量以及氮矿化速率、硝化潜势等微生物学过程显著高于20-200 cm,说明长期增施有机肥/秸秆还田等外源碳的添加对土壤养分及微生物学过程的影响主要发生在表层。（3）与NPK相比,NPKM处理能够显著增加100-200 cm深层土壤中NO3--N含量,NO3--N平均含量为17.8-26.1 mg·kg-1;而NPKS处理在一定程度上能够增加0-100 cm土层NO3--N含量,NO3--N平均含量为3.6-13.4 mg·kg-1,表明增施有机肥会促进土壤NO3--N的向下迁移,而秸秆还田对土壤NO3--N具有一定的固持作用。此外,由于有机肥和秸秆带入的氮素, NPKM、NPKM+、NPKS处理氮盈余比NPK处理增加312%、1 037%、953%,大大增加了土壤氮素淋失风险。【结论】在氮磷钾化肥基础上增施有机肥/秸秆还田会提高作物产量、增强土壤肥力,但会提高土壤氮盈余量,提高氮素淋失风险,尤其是增施有机肥会大大增加氮素淋失风险。  相似文献   

15.
Understanding the mechanism of soil organic carbon(SOC) sequestration is of paramount importance in sustaining crop productivity and mitigating climate change. Long-term trials were employed to investigate the responses of total SOC and its pools, i.e., mineral-associated OC(MOC), particulate OC(POC, containing Light-POC and Heavy-POC), to fertilization regimes at Yangling(25-year), Tianshui(35-year) and Pingliang(37-year) under a rain-fed cropping system in the Loess Plateau. The fertilization regimes in each trial included three treatments, i.e., control(no nutrient input, CK), chemical fertilizers(CF), and organic manure plus chemical fertilizers(MCF). Relative to the CK, long-term fertilization appreciably increased SOC storage by 134, 89 and 129 kg ha~(–1) yr~(–1) under CF, and 418, 153 and 384 kg ha~(–1) yr~(–1) under MCF in plough layer soils(0–20 cm), respectively, at the Yangling, Tianshui and Pingliang sites. The MOC pools accounted for 72, 67 and 64% of the total SOC at the above three sites with sequestration rates of 76, 57 and 83 kg ha~(–1) yr~(–1) under CF and 238, 118 and 156 kg ha~(–1) yr~(–1) under MCF, respectively. Moreover, the MOC pool displayed a saturation behavior under MCF conditions. The POC accordingly constituted 27, 33 and 36% of SOC, of which Light-POC accounted for 11, 17 and 22% and Heavy-POC for 17, 16 and 15% of SOC, respectively. The sequestration rates of POC were 58, 32 and 46 kg ha~(–1) yr~(–1) under CF, and 181, 90 and 228 kg ha~(–1) yr~(–1) under MCF at the three respective sites, in which Light-POC explained 59, 81 and 72% of POC under CF, and 60, 40 and 69% of POC under MCF, with Heavy-POC accounting for the balance. Compared with CK, the application of CF alone did not affect the proportions of MOC or total POC to SOC, whereas MCF application markedly reduced the proportion of MOC and increased the POC ratio, mainly in the Light-POC pool. The distribution of SOC among different pools was closely related to the distribution and stability of aggregates. The present study confirmed that organic manure amendment not only sequestered more SOC but also significantly altered the composition of SOC, thus improving SOC quality, which is possibly related to the SOC saturation level.  相似文献   

16.
吕海波  梁宗锁 《湖北农业科学》2012,51(12):2450-2452,2456
为了探索不同深度土壤对枯落物腐解的影响差异,通过对3个剌槐林样地C1、C2、C3的野外培育试验和室内培养试验,研究分析了添加枯落物后土壤有机碳(SOC)、颗粒态有机碳(POC)和总氮(TN)周期为4个月的两个阶段的含量变化以及3个深度土样59 d的CO2累计释放量.结果表明,SOC、POC及TN在两个阶段的变化量呈增减互补趋势,其变化幅度随深度增加而减小,表明枯落物腐解速率降低;室内培养试验中,SOC组分的差异造成了CO2累计释放量为20 cm＞60 cm＞40 cm.  相似文献   

17.
Soil organic carbon (SOC) is the most important indicators of soil quality and health. Identifying the spatial distribution of SOC and its influencing factors in cropland is crucial to understand the terrestrial carbon cycle and optimize agronomic management. Yunnan Province, characterized by mountainous topography and varied elevation, is one of the highest SOC regions in China. Yet its SOC stock of cropland and influencing factors has not been fully studied due to the lack of adequate soil investigation. In this study, the digital mapping of SOC at 1 km resolution and the estimation of total SOC stock in cropland of Yunnan Province was undertaken using 8 637 topsoil (0–20 cm) samples and a series of spatial data through Random Forest (RF) model. It was showed that across the cropland of Yunnan Province, the mean SOC density and total stock were 4.84 kg m–2 and 337.5 Mt, respectively. The spatial distribution indicated that relatively high SOC density regions resided in the northwest and northeast parts of Yunnan Province. Elevation (19.5%), temperature (17.3%), rainfall (14.5%), and Topographic wetness index (9.9%) were the most important factors which controlled spatial variability of SOC density. Agronomic practices (e.g., crop straw treatments, fertilizer management) should be optimized for the sustainable development of crop production with high SOC sequestration capacity in Yunnan Province.  相似文献   

18.
在内蒙古河套灌区通过微区试验,研究了秸秆深埋(S)、上盖秸秆下埋秸秆(简称上秸下秸,S+S)、上盖地膜下埋秸秆(简称上膜下秸,P+S)和地膜覆盖(对照,CK)4种耕作措施对0-40 cm土层水盐运移及食葵光合特性的影响。结果表明:(1)不同措施对土壤水盐调控的效果与作用时期差异较大。P+S在整个生育期内土壤盐分含量和盐溶质浓度较低,控盐效果显著;S+S仅在苗期能保墒控盐,但控盐效果比P+S差,后期出现水减盐增现象,保墒控盐效果也不佳;S在整个生育期内土壤盐分含量和盐溶质浓度最高,控盐效果最差;CK在整个生育期内土壤水分含量变化不大,而盐分含量较高,控盐效果也不明显。(2)不同措施对土壤水盐运移调控程度的差异,导致食葵光合特性也有明显变化。与CK、S、S+S相比,P+S由于其较低的盐溶质浓度环境,明显改善了其光合特性,在苗期、蕾期和花期能提高净光合速率(Pn)和蒸腾速率(Tr),增加气孔导度(Gs),降低胞间CO2浓度(Ci),从而使其作物长势和干物质积累明显高于其它措施。综合试验结果,P+S是内蒙古河套灌区盐碱地改良中优选的控抑盐耕作措施。  相似文献   

19.
The influence of agricultural management practices, such as organic fertilisation and plant densities on soil properties, root growth, and sesame yield were investigated. Soil samples (depth of 0–20 cm) were taken from a field study with sesame (Sesamum indicum L.) cultivated on a Chromic Luvisol, which was conducted to explore the effects of six fertilisation systems [Non-fertilisation (Control); Mineral fertilisation (Min); Organic fertilisation with 2 (Org-1) and 3 Mg ha–1 (Org-2) of commercial organic fertiliser Organus B; and with 1 (Tak 1) and 2 Mg ha–1 (Tak-2) of commercial organic fertiliser Takamix] and two plant densities [111111 (Pdens1) and 55555 (Pdens2) plants ha–1), in a factorial design (6 × 2) with four blocks. The highest values of soil organic carbon, total nitrogen, root density and sesame yield were found in the Org-2 fertilisation and Pdens1 treatments. We found that organic fertilisation combined with Pdens1 significantly increased root growth. Organic fertilisation treatments were able to maintain 80% of sesame roots distributed at a soil depth of 0–10 cm, whereas the last 20% were distributed at a soil depth of 10.1–20 cm. In conclusion the utilization of commercial organic fertilisers as an organic matter source enhanced soil organic carbon, total nitrogen, and root density that contributed to increase sesame yield. Our findings also suggest that inputs of organic matter source with a correct plant density might change positively soil organic carbon and total nitrogen, root growth, root distribution and sesame yield.  相似文献   

20.
An improved straw mulching model may be a sustainable agricultural production technology due to its improvements in soil water and the fertilizer environment by the recycling of waste straw resources. A four-year field experiment was conducted in a randomized block design on the Loess Plateau of northwestern China in 2015–2019, which aimed to study the effects of straw strip mulching (SSM) and conventional flat planting without mulching (CK) on soil water storage, water consumption characteristics, water use efficiency, precipitation use efficiency, winter wheat growth, economic benefits, and nutrient benefits. The results obtained for the four years showed that the SSM treatment improved soil water storage in the 0–180 cm soil layer over the whole growth period, which was especially obvious in the 0–60 cm soil layer at the jointing and blooming stages. Compared with CK, SSM increased the contribution rate of precipitation to total evapotranspiration and increased it quite significantly by 20.4 percentage points in the earlier growth period. SSM significantly reduced soil water storage consumption in the 0–180 cm soil layer and ultimately reduced evapotranspiration by 11.2 mm during the whole period. In the 0–180 cm soil layer, SSM decreased evapotranspiration by 33.1 mm from the sowing to the jointing stages, but increased it by 19.5 mm from the jointing to the blooming stages. In addition, SSM improved the water use efficiency of grain yield by 21.6% and improved the precipitation use efficiency of grain yield by 18.6%, and it ultimately increased grain yield by 16.5% through improving spike number by 9.5% and kernel number per spike by 8.9%. SSM improved the water use efficiency of biomass yield by 13.5% and the precipitation use efficiency of biomass yield by 9.9%, and it ultimately increased biomass yield by 8.7% and plant height by 6.5%. Furthermore, SSM increased net income by 413 CNY ha–1 and the total amount of straw returned to the field after harvest by 8 876–9 619 kg ha–1. After returning straw to the field, SSM significantly increased the soil nutrient contents, which could significantly reduce the burden of fertilization by farmers after a few years. Therefore, straw strip mulching technology could probably be a sustainable and potentially useful practice, which could save water and increase efficiency in rainfed winter wheat production.  相似文献   

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