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1.

Tillage systems and fertilization have important effects on soil microorganism activity. Information regarding the simultaneous evaluation of long-term tillage and fertilization on soil microbial traits in sunflower fields is not available. Therefore, this study was conducted to determine the best tillage and fertilization system for soil microbial parameters. The experimental design was a split plot based on a randomized complete block design with three replications. Main plots consisted of the long-term tillage systems (1999–2011) including: no tillage (NT), minimum tillage (MT) and conventional tillage (CT). Six methods of fertilization, including farmyard manure (N1), compost (N2), chemical fertilizers (N3), farmyard manure + compost (N4); farmyard manure + compost + chemical fertilizers (N5), and control (N6) were arranged in subplots. Results showed that the highest amount of microbial biomass was observed in treatment NTN4. The highest and lowest values of enzyme activities (acid, alkaline phosphatase, urease, dehydrogenase and protease) were found in organic fertilizers + NT and chemical fertilizers + CT plots, respectively. Highest basal and induced respiration values were found for NTN4 treatment. Correlation coefficients between enzyme activity, respiration and microbial biomass carbon were significant.  相似文献   

2.
Abstract. The effects of deep tillage, straw mulching and farmyard manure on maize growth in loamy sand and sandy loam soils were studied in experiments lasting three years. Treatments included all combinations of conventional tillage (10 cm deep) and deep tillage (35–40 cm deep), two farmyard manure rates (0 and 15 t/ha) and two mulch rates (0 and 6 t/ha), replicated three times in a randomixed block design.
Deep tillage decreased soil strength and caused deeper and denser rooting. Mulching decreased maximum soil temperature and kept the surface layers wetter resulting in better root growth. Farmyard manure also improved root growth, and the crop then extracted soil water more efficiently. All three treatments increased grain yield in the loamy sand, but in the sandy loam only tillage and farmyard manure increased yields significantly. Deep tillage and straw mulch effects varied with soil type and amount of rainfall in the growing season. In the loamy sand the mean responses to deep tillage and mulching were largest in a dry year. A tillage-mulch interaction was significant in the loamy sand.  相似文献   

3.
A 12-year field experiment was conducted to investigate the effect of different tillage methods and fertil-ization systems on microbial biomass C,N and P of a gray fluvo-aguic soil in rice-based cropping system .Five fertilization treatments were designed under conventional tillae(CT) or on tillage(NT) system:no fertilizer(CK) ; chemical fertilizer only(CF) ; combining chemical fertilizer with pig manure(PM); combining chemical fertilizer with crop straw (CS) and fallow (F). The results showed that biomass C,N and P were enriched in the surface layer of no-tilled soil,whereas they distributed relatively evenly in the tilled soil,which might result from enrichment of crop resdue,organic manure and mineral fertilzer,and surficial developent of root systems under NT.Under the cultivation system NT had slightly greater biomass C,N and P at 0-5 cm depth ,significantly less biomass C,N and P at 5-15 cm depth ,less microbial biomass C,N and equivalent biomass P at 15-30 cm depth as compared to CT,indicating hat tillage was beneficial for the multiplication of organims in the plowed layer of soil.Under the fallow system,biomass C,N and P in the surface layer were significantly greater for NT than CT while their differences between the two tillage methods were neligible in the deeper layers.In the surface layer,biomass C,N and P in the soils amended with oranic manure combined with mineral fertilizers were significantly greater than those of the treatments only with mineral fertilizers and the control.Soils without fertilzer had the least biomass nutrient contents among the five fertilization treatments.Obviously,the long-term application of organic manure could maintain the higher activity of microorganisms in soils.The amounts of biomass C,N and P in the fallowed soils varied with the tillage methods;they were much greater under NT than under CT,especially in the surface layer,suggesting that the frequent plowing could decrease the content of organic matter in the surface layer of the fallowed soil.  相似文献   

4.
Reducing the tillage and application of mulch are important strategies for soil and water conservation and sustainability of agricultural systems. Soil can be a source or sink for carbon (C) depending on management strategies and plays a major role in the global C cycle. These interacting practices can alter nutrient movement and availability to the crops, reduce water loss, slow down organic-matter (OM) decomposition, and thus enhance C sequestration. A 2-year field study was conducted to quantify the tillage and mulching effect on soil organic C (SOC), OM, nitrogen (N), phosphorus (P), and potassium (K) at two depths (i.e., 0–15 and 15–30 cm deep) in the soil profile and N, P, and K concentrations (g kg?1) in plant shoots at harvest on a Typic Calciargids in wheat–maize rotation. The four tillage systems used were zero tillage (ZT), minimum tillage (MT), conventional tillage (CT), and deep tillage (DT), and four mulch rates [control, 2 (M2), 4 (M4), and 6 (M6) Mg ha?1 year?1 wheat (Triticum aestivum L.) straw] were applied in combination with each tillage system, keeping recommended rates of fertilizers. There was a linear positive response of mulch application on SOC for both years, but it was more pronounced during the second year. Greater values were found in ZT and the lowest in CT at all depths, although greater SOC content was found in upper layers than in deeper ones. Greater shoot N, P, and K concentrations were found in MT, CT, and DT, whereas the lowest concentration was found in ZT. Mulch application has no effect on N, P, and K concentrations in shoots. The soil N concentration was not affected by tillage and mulch, yet greater soil N content was found at 0–15 cm than 15–30 cm deep. There was significant effect of tillage on soil P and K during one year as greater P and K concentrations were found under MT, CT, and DT compared to ZT. More N, P, K, and OM concentrations were found at 0–15 cm deep than at 15–30 cm deep during the whole study period. Mulch effect was significant on K, and significantly greater amounts were found at greater levels of mulch application. The increases in the soil OM were 34.5, 35.75, and 24% at 0–8, 8–16, and 16–24 cm deep respectively from the first year to the second year. Tillage effect on soil organic-matter content was not significant. Tillage increased grain production for both years. For the first year, 22.9 and 27% greater yields were found in CT and DT, whereas in the second year yields were 10.6, 17.9, and 57% greater, respectively, in MT, CT, and DT as compared to ZT. Grain production was increased at a result of mulch application by 12.9, 20.3, and 10.6% during the first year and 11.45, 23.74, and 10.9% during the second year as compared to control (i.e., without mulch). Results show the importance of mulch application and crop residue retention. Both can increase the SOC content and water-holding capacity, which will result in improved production and soil physical health over long and continuous use of mulch.  相似文献   

5.
中国黄土高原区轮耕对土壤团聚体、有机碳氮含量的影响   总被引：2，自引：0，他引：2  
In rain-fed semi-arid agroecosystems, continuous conventional tillage can cause serious problems in soil quality and crop production, whereas rotational tillage (no-tillage and subsoiling) could decrease soil bulk density, and increase soil aggregates and organic carbon in the 0-40 cm soil layer. A 3-year field study was conducted to determine the effect of tillage practices on soil organic carbon (SOC), total nitrogen (TN), water-stable aggregate size distribution and aggregate C and N sequestration from 0 to 40 cm soil in semi-arid areas of southern Ningxia. Three tillage treatments were tested: no-tillage in year 1, subsoiling in year 2, and no-tillage in year 3 (NT-ST-NT); subsoiling in year 1, no-tillage in year 2, and subsoiling in year 3 (ST-NT-ST); and conventional tillage over years 1-3 (CT). Mean values of soil bulk density in 0-40 cm under NT-ST-NT and ST-NT-ST were significantly decreased by 3.3% and 6.5%, respectively, compared with CT, while soil total porosity was greatly improved. Rotational tillage increased SOC, TN, and water-stable aggregates in the 0-40 cm soil, with the greatest effect under ST-NT-ST. In 0-20 and 20-40 cm soils, the tillage effect was confined to the 2-0.25 mm size fraction of soil aggregates, and rotational tillage treatments obtained significantly higher SOC and TN contents than conventional tillage. No significant differences were detected in SOC and TN contents in the >2 mm and <0.25 mm aggregates among all treatments. In conclusion, rotational tillage practices could significantly increase SOC and TN levels, due to a fundamental change in soil structure, and maintain agroecosystem sustainability in the Loess Plateau area of China.  相似文献   

6.
Field experiments were conducted on rainfed wheat and mungbean for two consecutive seasons on a Udic Ustocrept to evaluate the effect of tillage techniques, fertilization, and weeding on crop yields and nutrient uptake. Tillage techniques were conventional, zero, and deep tillage. Fertilizer treatments consisted of a control, nitrogen (N) and phosphorus (P) fertilizer, and farmyard manure plus fertilizer. Grain yield of wheat (Triticum aestivum L.) was 2,404 kg/ha under conventional tillage, 2,008 kg/ha under zero tillage, and 2,839 kg/ha under deep tillage. Total dry matter of wheat was 7,612 kg/ha under deep tillage, 6,671 kg/ha under conventional tillage, and 6,016 kg/ha under zero tillage. Fertilizer application increased wheat grain yield by 112% and total dry matter by 150% over the control. Weed biomass of wheat was 57% greater under zero tillage than under conventional tillage. Mungbean (Vigna radiata L.) grain yield was 371 kg/ha under conventional tillage, 248 kg/ha under zero tillage, and 367 kg/ha under deep tillage. Mungbean total dry matter yield was 2,018 kg/ha under deep tillage, 1,814 kg/ha under conventional, and 1,143 kg/ha under zero tillage. Dry weed biomass in mungbean was 38% greater under zero tillage and 6% lesser under deep tillage than that of conventional tillage. Nitrogen and P uptake by weeds was greater under zero tillage compared with conventional and deep tillage.  相似文献   

7.
Field experiments were conducted in 2010 and 2011 at the Agricultural College of Shiraz University to evaluate the effects of cattle manure and nitrogen (N) fertilizers on soil properties such as soil organic carbon (SOC), soil organic nitrogen (SON), soil electrical conductivity, soil pH and corn yield under two tillage systems. Treatments included tillage systems in two levels as conventional tillage and reduced tillage as subplots, cattle manure (0, 25 and 50 tons ha?1) and N fertilizer (0, 125 and 250 kg N ha?1) as sub-subplots. Results showed that SOC and SON were significantly affected by tillage system in both years of the experiment. SOC and SON were higher in reduced tillage compared to conventional tillage. Tillage system had no significant effect on grain yield, plant height and 1000 seed weight. Increased cattle manure rates at 25 and 50 tons ha?1 increased grain yield by 27% and 38%, respectively, in 2010 and 25% and 25% in 2011. The results showed that application of cattle manure combined with N fertilizer might be an efficient management to increase soil productivity in southern Iran, in soils with poor organic content. Additionally, reduced tillage showed to be an efficient method to increase soil organic matter.  相似文献   

8.
Vegetation strips (VS) along with conservation tillage, application of organic amendments and weed mulching improve crop yields by reducing run‐off and topsoil erosion. To investigate these issues, an experiment was conducted under rainfed conditions using grass VS for four and a half years (June 2007 to October 2011) at Dehradun, Uttarakhand, in the Indian Himalayan region. VS were incorporated in the experimental plots (Entisols) in a randomized complete block design in permanent 100 × 20 m (2000 m2) plots with a 2% slope to evaluate the effects of vegetation strips on run‐off, soil loss and crop yield. Three treatments were evaluated: (i) without VS with recommended NPK under conventional tillage, (ii) panicum as VS with recommended NPK under conventional tillage and (iii) palmarosa+ that consists of palmarosa as VS along with organic amendments (farmyard manure, vermicompost and poultry manure) and weed mulch under minimum tillage. The results show that soil loss and run‐off were significantly lower (P < 0.05) in plots under palmarosa+ than without VS treatment. Mean soil loss of 3.4, 5.2 and 7.1 t/ha was recorded from palmarosa+, panicum and without VS treated plots, respectively. Mean run‐off was 234, 356 and 428 mm from plots under palmarosa+, panicum and without VS, respectively. Maize yield was lower on the plots under palmarosa+ compared with panicum, but significantly higher (P < 0.05) than without a strip. The succeeding rainfed wheat yield was significantly greater in plots under palmarosa+ than in the initial years. The wheat yield equivalent was significantly higher in plots under palmarosa+ followed by panicum and without VS. Thus, vegetation strips are recommended for wider adoption to reduce run‐off and soil loss and to increase crop yield. The long‐term goal is to achieve a palmarosa+ system (palmarosa as a vegetation strip along with organic amendments, farmyard manure, vermicompost and poultry manure) and weed mulch under minimum tillage.  相似文献   

9.
《Applied soil ecology》2006,34(3):278-285
We studied the effects of long-term organic and mineral fertilization on soil microarthropods and soil chemical parameters in a field experiment under semi-arid conditions in Central Spain. Two different regimes of organic manuring, i.e. farmyard manure applied once in 3 years versus annual manuring with crop residues were compared. Soil carbon and nitrogen contents were increased markedly by farmyard manure, whereas straw and green manure had no significant effect. In contrast, the abundance of soil microarthropods was increased by annual application of straw and green manure, but not by farmyard manure last applied 2.5 years before sampling. We conclude that in the field experiment under study the abundance of soil microarthropods was influenced by the immediate food supply rather than by soil chemical parameters, such as carbon and nitrogen content or the pH. Biodiversity of soil microarthropods, as estimated by the Shannon index, was not affected significantly by straw and green manure. Obviously, other management practices, especially tillage, are limiting the species composition of soil microarthropods and thereby overshadow possible effects of fertilization on diversity.  相似文献   

10.
A limiting factor to the no-tillage system in arid and semi-arid regions is the possibility of soil densification from lack of tillage. This research examines the extent and duration of the effects of periodic (rotational) zone-tillage over 2 years, on selected soil physical and chemical properties and crop yields. In the first year four tillage treatments were applied: conventional tillage with mouldboard plow (CT), minimum tillage with chisel plow (MT), no-tillage (NT) and zone-tillage subsoiling with a paraplow (ZT). In the second year, the ZT plots were returned to NT to follow the residual effects of ZT. The soil was a loamy sand (Calcic Haploxeralf) from semi-arid Central Spain and the crop rotation was grey pea (Pisum sativum L.)–barley (Hordeum vulgare L.). Crop residues on the soil surface after sowing grey pea were 85% in NT plots, 55% in ZT plots and 15% in MT plots. When comparing NT and ZT, the immediate effects of subsoiling on soil physical properties were significant (P < 0.05). Soil strength as measured by cone index approached 3.0 MPa in NT and was reduced to <1.0 MPa by ZT over 300 mm sampling depth. Soil moisture content and bulk density were improved by ZT. No-till and ZT favoured surface accumulation of soil organic carbon (SOC), total N and available P and K. Stratification ratio of SOC was not different among tillage systems, but soil N stratification ratio followed the order NT > ZT > MT > CT. Grey pea yields were reduced by 3 Mg ha−1 in the NT and MT compared with ZT. Crop residues on the soil surface after barley sowing were 80% in NT, 56% in ZT, and 12% in MT. At the end of the second year, soil strength, soil moisture and bulk density in ZT declined to NT levels at all soil depths. The positive effect of ZT in increasing SOC in the top layer had also disappeared. However, total N, and available P and K concentrations under NT and ZT were still significantly higher than in MT and CT. Stratification ratios of SOC under NT and ZT were >2 and more than two-fold those under MT and CT. Nitrogen stratification ratio under ZT increased and no significant differences between NT and ZT could be reported. Barley yield was 0.6 Mg ha−1 higher in ZT compared with NT. Our results suggest that ZT improved the physical and chemical condition of the soil studied in months following subsoiling. These positive effects, however, diminished with time and only some residual effects on total N and available P and K content in the top-layer were still evident after 2 years.  相似文献   

11.
Abstract

Soil carbon sequestration in agricultural lands has been deemed a sustainable option to mitigate rising atmospheric CO2 levels. In this context, the effects of different tillage and C input management (residue management and manure application) practices on crop yields, residue C and annual changes in total soil organic C (SOC) (0–30 cm depth) were investigated over one cycle of a 4-year crop rotation (2003–2006) on a cropped Andisol in northern Japan. For tillage practices, the effects of reduced tillage (no deep plowing, a single shallow harrowing for seedbed preparation [RT]) and conventional deep moldboard plow tillage (CT) were compared. The combination of RT, residue return and manure application (20 Mg ha?1 in each year) increased spring wheat and potato yields significantly; however, soybean and sugar beet yields were not influenced by tillage practices. For all crops studied, manure application enhanced the production of above-ground residue C. Thus, manure application served not only as a direct input of C to the soil, but the greater crop biomass production engendered enhanced subsequent C inputs to the soil from residues. The SOC contents in both the 0–5 cm and 5–10 cm layers of the soil profile were greater under RT than under CT treatments because the crop residue and manure were densely incorporated into the shallow soil layers. Comparatively, neither tillage nor C input management practices had significant effects on annual changes in SOC content in either the 10–20 cm or 20–30 cm layers of the soil profile. When soil C sequestration rates, as represented by annual changes in total SOC (0–30 cm), were assessed on a total soil mass basis, an anova showed that tillage practices had no significant effect on total C sequestration, but C input management practices had significant positive effects (P ≤ 0.05). These results indicate that continuous C input to the soil through crop residue return and manure application is a crucial practice for enhancing crop yields and soil C sequestration in the Andisol region of northern Japan.  相似文献   

12.
In a long-term field trial (Halle, Germany, founded in 1949 by K. Schmalfuß, soil type Haplic Phaeozem), the effects of different mineral and organic fertilization on dry matter yields, soil C and N contents and N balances were investigated. Over a period of 60 years, yields increased on average in all cultivated crops (winter and spring cereals, potatoes, sugar beets, silage maize), even without any fertilization. Nitrogen deficiency in unfertilized and PK treatments caused strong decreases in yield (up to 48%) in comparison with the N2PK standard treatment. The effect of omitting K or P supply was smaller (up to 18% and 7% yield reduction, respectively). The highest yields were obtained with high mineral N + PK application and (except winter wheat) with farmyard manure in combination with mineral fertilization. The N balances were negative in all treatments. However, if N immission from the air (40 kg ha?1 a?1) was included in the calculation, N balances were negative only in low N treatments. The soil C and N contents increased up to 1975. A considerable decrease has been seen since about 1985. The highest soil C and N contents were observed in the farmyard manure treatments. In addition to fertilization effects, this development of soil properties reflects changes in environmental pollution, climatic changes, as well as shifts in cultivation methods like tillage depths, over recent decades.  相似文献   

13.
ABSTRACT

We conducted a field- and pot experiment with peas to investigate the impact of soil tillage and herbicide applications on arbuscular mycorrhizal fungi (AMF), plant growth, phosphorus concentrations, C:N ratio in plants and yield. The field study was carried out in a long-term soil tillage experiment where four tillage treatments have been compared. Field soil from the experimental plots were used for the pot experiment. AMF were not affected by herbicide (MCPB) application, neither in the field nor in the pot experiments. However, AMF root colonization was enhanced by reduced tillage, minimum tillage and no-tillage practices, compared to conventional tillage. In the pot experiment, plant growth and nodulation of pea roots was negatively affected by the high herbicide dosage. In the field experiment neither tillage nor herbicide treatment exert specific effects on root growth parameters, phosphorus concentrations, C:N ratio and plant dry matter. This work demonstrates that an appropriate herbicide usage coupled with conservation soil tillage techniques can favour AMF root colonization and benefit plant growth.

Abbreviations: AMF: arbuscular mycorrhizal fungi; CT: conventional tillage; RT: reduced tillage; MT: minimum tillage; NT: no tillage; P: Phosphorus; C:N ratio: carbon:nitrogen ratio  相似文献   

14.
The effects of cropping systems and management practices on soil properties provide essential information for assessing sustainability and environmental impact. Tillage and fertilizer rates were evaluated for their effects on soil bulk density (BD), penetration resistance, soil organic carbon (SOC) concentration and availability of macronutrients on a sandy clay loam (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA; Luvic Yermosol, FAO) in a semi-arid region of Pakistan. Wheat (Triticum aestivum L.) and cotton (Gossypium hirsutum L.) were double-cropped from 1996 to 1998. Tillage treatments were minimum till (MT), conventional till (CT), and deep till (DT). Low, medium and high fertilizer rates were applied to wheat and cotton. BD was affected neither by tillage nor fertilizer rates. Soil penetration resistance was lower for DT than CT and MT. Tillage methods affected soil P concentration but did not affect N and K concentrations. However, fertilizer application significantly increased soil P and K concentrations. Concentrations of N, P, K and SOC were greater in the plough layer than sub-soil. Grain yield of wheat was significantly negatively correlated with penetration resistance and was positively correlated with soil P and K concentrations. Yield of cotton was significantly negatively correlated with soil BD. These data provide an experimental basis to re-evaluate recommendations for fertilizer rates and tillage methods for production of wheat and cotton in Punjab. Further, there is a strong need to establish long-term experiments to study agronomic and environmental effects of tillage methods, fertilizer rates, and cropping systems on productivity and environment quality.  相似文献   

15.
为明确不同深耕方式和有机物料配施还田对石灰性黑钙土化学性质影响及持续改土效果,在黑龙江省安达市石灰性黑钙土上开展了深松、秸秆心土还田、秸秆心土还田+鸡粪3种深耕处理对土壤p H值、盐基离子、有效氮、磷、钾和玉米持续增产效果研究,并与常规耕作进行了比较。结果表明:深耕处理可以改变土壤酸碱度及盐基离子浓度,明显降低土壤p H值,降低幅度分别为0.59~0.96,土壤的水溶性钾、水溶性钠、HCO3-离子质量分数降低幅度分别为0.9~6.9、79.6~272.1、19.5~46.6 mg/kg,提高水溶性钙离子质量分数,幅度为36.5~125.6 6 mg/kg,土壤p H值与水溶性钠、HCO3-离子含量显著正相关,与土壤水溶性钙离子含量呈显著负相关;深耕处理可提高深层土壤有效氮、磷、钾含量,在20~50 cm土层,各处理土壤碱解氮、有效磷、速效钾含量高于对照,顺序为秸秆心土还田+鸡粪秸秆心土还田深松对照,其中秸秆心土还田+鸡粪处理对土壤有效氮、磷、钾影响最明显,高于对照幅度分别为13.5~36.0、2.4~4.1、41.2~71.3 mg/kg;深耕可以增加玉米产量,不同深耕技术增产效果不同,秸秆心土还田和秸秆心土还田+鸡粪处理一次改土后,连续3a均表现增产趋势,秸秆心土还田+鸡粪改土后第1年比对照增加47.1%,第2年和第3年分别比对照增产25.2%和24.7%,3a平均比对照增产32.3%,效果显著,秸秆心土还田处理与对照相比增产效果不如秸秆心土还田+鸡粪处理,第1、2和3年增产分别为11.2%、9.8%和18.1%,3a平均增产11.3%,深松处理增产效果在不同年份表现不一致,第1年没有增产,第2年增产6.3%,第3年增产14.3%,3a平均增产6.2%;从土壤化学性质的变化及改土后玉米产量看出,秸秆心土还田+鸡粪处理是比较适合石灰性黑钙土改良的耕作措施。  相似文献   

16.
长期施氮、磷、钾化肥对玉米产量及土壤肥力的影响   总被引：53，自引：3，他引：53  
以1990年建立的国家褐潮土土壤肥力与肥料效益长期监测基地(北京昌平站)的长期肥料定位试验为研究平台,研究了不同施肥制度对玉米产量和土壤肥力的影响。结果表明,长期均衡地施NPK肥或NPK与有机肥配施,可以显著提高玉米产量和土壤有机质、全氮、全磷、速效氮、速效磷、速效钾等肥力指标,并能提高土壤微量元素的含量;而不均衡施肥(N、NK、NP、PK)导致相应的营养元素的耗竭。相关分析表明,在褐潮土上增施磷肥和有机肥对提高玉米产量具有重要的作用。  相似文献   

17.
Abstract

Tillage systems may affect many soil properties, which in turn may alter the soil environment and consequently impact on root growth and distribution, and crop yield. In 1993, a long-term field experiment on sustainable crop rotation and ley farming systems was initiated on a Colombian acid-savanna oxisol to test the effects of grain legumes, green manures, intercrops and leys as possible components that could increase the stability of systems involving annual crops. In the present study, five agropastoral treatments (maize monoculture, maize-soybean rotation, maize-soybean green manure rotation, native savanna, maize-agropastoral rotation) under two tillage systems (no tillage and minimum tillage) were investigated. Lower bulk density and higher total porosity for all treatments and soil layers were found in no-tillage compared to the minimum tillage system. Between the two tillage systems, significantly higher maize grain yields (p<0.1) were obtained under no-tillage agropastoral treatments compared to the same treatments under minimum tillage. Maize yields on native savanna soils were markedly lower than in the rest of the treatments, indicating the need for improved soil conditions in subsoil layers for root growth of maize.  相似文献   

18.
Soil organic matter (SOM) and phosphorus (P) fractions play a key role in sustaining the productivity of acid-savanna oxisols and are greatly influenced by tillage practices. In 1993, a long-term experiment on sustainable crop rotation and ley farming systems was initiated on a Colombian acid-savanna oxisol to test the effects of grain legumes, green manures, intercrops and leys as possible components that could increase the stability of systems involving annual cereal crops. Five agropastoral treatments (maize monoculture—MMO, maize–soybean rotation—MRT, maize–soybean green manure rotation—MGM, native savanna control—NSC and maize-agropastoral rotation—MAP) under two tillage systems (no till-NT and minimum tillage-MT) were investigated. The effects of NT and MT on SOM and P fractions as well as maize grain yield under the five agropastoral treatments were evaluated. Results showed that soil total C, N and P were generally better under no-till as compared to minimum-tilled soils. While P fractions were also generally higher under no-till treatments, SOM fractions did not show any specific trend. Seven years after establishment of the long-term ley farming experiment (5 years of conventional tillage followed by 2 years alternative tillage systems), MT resulted into moderately higher maize grain yields as compared to NT. The MGM rotation treatment had significantly higher values of maize yield under both tillage systems (4.2 Mg) compared to the NSC (2.3 Mg ha−1). Results from this study indicate that the rotational systems (maize–soybean green manure and maize-pastures) improved the soil conditions to implement the no-till or minimum tillage systems on Colombian savanna oxisol.  相似文献   

19.
The impacts of tillage and organic fertilization on soil organic matter (SOM) are highly variable and still unpredictable, and their interactions need to be investigated under various soil, climate and cropping system conditions. Our work examined the effect of reduced tillage and animal manure on SOM stocks and quality in the 0–40 cm layer of a loamy soil under mixed cropping system and humid temperate climate. The soil organic carbon (SOC) and N stocks, particulate organic matter (POM), and C and N mineralization potential (301 days at 15 °C) were measured in a 8‐yr‐old split‐plot field trial, including three tillage treatments [mouldboard ploughing (MP), shallow tillage (ST), no tillage (NT)] and two fertilization treatments [mineral (M), poultry manure 2.2 t/ha/yr C (O)]. No statistically significant interactive effects of tillage and fertilization were measured except on C mineralization. NT and ST showed greater SOC stocks (41.2 and 39.7 t/ha C) than MP (37.1 t/ha C) in the 0–15 cm increment, while no statistical differences were observed at a greater depth. N stocks exhibited similar distribution patterns with regard to tillage effect. Animal manure, applied at a rate representative of typical field application rates, had a smaller impact on SOC and N stocks than tillage. The mean SOC and N stocks were higher under O than M, but the differences were statistically significant only in the 0–5 cm increment. MP showed lower C‐POM stocks than NT and ST in the 0–5 cm increment, whereas greater C‐POM stocks were measured under MP than under NT or under ST in the 20–25 cm increment. Organic fertilization had no impact on C‐POM or N‐POM stocks. In the 0–25 cm increment, NT showed a lower C and N mineralization potential than MP. Our work shows that the sensitivity of SOM to reduced tillage for the whole soil profile can be relatively small in a loamy soil, under humid‐temperate climate. However, POM was particularly sensitive to the differential effects of tillage practices with depth, and indicative of differentiation in total SOM distribution in the soil profile.  相似文献   

20.
长期免耕与施用有机肥对土壤微生物生物量碳、氮、磷的影响   总被引：264，自引：7，他引：264  
通过设置在江苏省句容农科所的田间定位试验研究长期免耕及施用有机肥料对土壤微生物生物量碳、氮、磷的影响。结果表明 :经过 1 6年 32茬稻—麦水旱轮作后 ,表土层 ( 0～ 5cm)土壤微生物生物量碳、氮、磷含量比亚表层 ( 5～ 1 0cm)分别高 2 7.5 %、43.6%和1 1 %。与常规耕翻相比长期免耕处理表土层土壤微生物生物量碳、氮含量分别增加了2 5 .4%和 45 .4% ,而微生物生物量磷无明显变化规律 ;亚表层的土壤微生物生物量碳、氮、磷免耕与耕翻两种耕作方式间的差异不显著。尽管各施肥处理施用的氮、磷、钾数量完全相等 ,但土壤微生物生物量碳、氮、磷的含量却因肥料种类的不同而异。综合 0～ 5和 5～ 1 0cm土层 ,微生物生物量碳、磷为 :猪粪 化肥 >秸秆 化肥 >绿肥 化肥 >化肥 >不施肥 ,微生物生物量氮则为 :猪粪 化肥 >绿肥 化肥 >秸秆 化肥 >化肥 >不施肥。相关分析结果显示 ,土壤微生物生物量碳、氮与土壤有机碳、土壤全氮和土壤碱解氮之间均呈极显著的正相关 ,表明其与土壤肥力关系密切 ,可作为评价土壤肥力性状的生物学指标  相似文献   

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