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1.
通过分析裂区设计下的6个处理,即小麦季深耕和旋耕2个主处理×玉米季免耕播种、行间深松和行内深松3个副处理:(1)旋耕+免耕播种(RT—NT);(2)旋耕+行间深松(RT—SBR);(3)旋耕+行内深松(RT—SIR);(4)深耕+免耕播种(DT—NT);(5)深耕+行间深松(DT—SBR);(6)深耕+行内深松(DT—SIR),对土壤养分含量和作物产量影响,筛选适宜于小麦—玉米轮作体系的耕作模式。结果表明,各处理土壤养分含量在小麦、玉米两季中均随土层深度增加而降低。小麦季,旋耕处理0—10cm土层土壤全氮、碱解氮、有效磷含量、硝态氮含量显著高于深耕处理;但深耕增加当季30—40cm土层土壤有机质、全氮、碱解氮、有效磷、硝态氮、铵态氮含量。玉米季,DT—NT处理0—30cm土层有机质含量较RT—NT处理增加40.1%～64.3%。RT—SBR、RT—SIR处理显著提升土壤0—30cm全氮含量,其中RT—SBR处理0—10cm土层全氮含量最高,为1.4g/kg。RT—SIR处理显著增加0—20cm土壤碱解氮含量,较RT—NT显著增加15.0%～25.3%。在0—40cm土层,DT—SBR处理的有效磷含量最高,而RT—SBR处理的速效钾含量最高。DT—SIR处理显著提升20—50cm土层硝态氮和铵态氮含量,其中硝态氮含量为8.5～30.4mg/kg,铵态氮含量为2.6～8.9mg/kg。与小麦季相比,玉米季提升10—20cm土层有机质含量、0—50cm土层的碱解氮、有效磷、速效钾含量以及40—50cm土层的硝态氮、铵态氮含量。DT—SBR和DT—SIR处理穗长、百粒重、收获指数和产量显著高于其他处理,且二者产量较RT—NT处理显著增加6.4%～10.8%。玉米季DT—SIR处理的肥料偏利用率和经济效益最高。综上所述,深耕+行内深松处理有利于增加土壤养分含量,且增产效果较好,在本研究中最优。  相似文献   

2.
研究深松深度对砂姜黑土耕层特性、作物产量和水分利用效率的影响,可为构建砂姜黑土合理耕层的耕作深度指标提供依据。本研究基于多年定位大田试验,采用大区对比设计,设置4个深松深度(30 cm、40 cm、50 cm、60 cm)处理,以旋耕(RT,平均耕作深度为15 cm)作为对照,研究不同深松深度对土壤紧实度、土壤三相比(R)值、作物根系形态、作物产量和水分利用效率的影响。研究结果表明,深松深度增加能显著降低土壤紧实度,使土壤的三相比(R)更加合理,进而促进作物根系生长。不同深松深度中,深松60 cm处理的土壤紧实度和三相比(R)值与对照相比降幅最大,深松40 cm处理的冬小麦根系生物量最大,深松50 cm处理的夏玉米根系生物量最大。深松不仅增加作物产量,还提高作物水分利用效率。深松30 cm处理的周年作物产量最高,比对照增产12.2%,但与深松40 cm处理差异不显著。深松50 cm处理的周年水分利用效率最高,但与深松30 cm和深松40 cm处理差异不显著。深松30 cm、40 cm和50 cm的周年水分利用效率比对照分别增加9.1%、8.8%和12.7%。因此,砂姜黑土适宜的深松深度为30~40 cm。  相似文献   

3.
Little is known how contrasting tillage (deep ploughing, top- and sub-soil loosening with straight or bent leg cultivator [BLC], direct drilling [DD]) affect important soil physical properties (total porosity [TP], pore size distribution [PSD], water release characteristics [WRC]) and CO2 emissions from a Luvisol. The study was aimed to alleviate compaction on land that had been under reduced tillage for 4 successive years. Undisturbed core samples were collected from 5–10, 15–20 and 25–30 cm depths for soil WRCs, TP and pore-size distribution determination. A closed chamber method was used to quantify the CO2 emissions from the soil. Soil loosening with straight or BLC produced the highest total soil porosity (on average 0.48 m3 m?3) within 5–30 cm soil layer, while conventional tillage (CT) gave 6%, DD up to 25% reduction. Sub-surface loosening with a BLC was the most effective tool to increase the amount of macro- and mesopores in the top- and sub-soil layers. It produced 21% more macro- and mesopores within 25–30 cm soil layer as compared to the soil loosened with a straight leg cultivator. Plant available water content under CT and DD was lower as compared to that under deep loosening with straight or BLC (23% and 18%, respectively). DD produced 12% lower soil surface net carbon dioxide exchange rate than CT and by 25–28% lower than deep soil loosening with straight or BLC. The increase in micropores within 25–30 cm soil layer caused net carbon dioxide exchange rate reduction. The amount of mesopores within the whole 5–30 cm soil layer acted as a direct dominant factor influencing net CO2 exchange rate (NCER) (Pxy = ?3.063; r = 0.86).  相似文献   

4.
不同机械深耕的改土及促进作物生长和增产效果   总被引：2，自引：0，他引：2  
长期不合理耕作导致土壤结构性能恶化、土壤耕性变差,限制作物根系下扎、影响土壤生产潜力发挥。为了改善土壤耕层构造,该试验采用自主研发的改土机械ES-210型深松犁和前置式心土(亚表层)耕作犁进行深耕,以灭茬旋耕(常规耕作)为对照,进行大区耕作对比试验。结果表明:1)深松、亚表层耕作处理与对照相比,耕层土壤固相率分别降低1.6%~3.3%、2.8%~4.5%,液相、汽相相对增加,三相比更趋于合理化;打破犁底层,降低耕层土壤硬度,其中20~35 cm土层效果更为明显;耕层土壤有效水含量上升1.1%~1.2%、0.9%,束缚水(无效水)含量下降0.4%~1.1%、0.5%~0.9%。2)深松、亚表层耕作处理比对照根长增长,其中甜菜增长5.1%、2.9%,大豆增长11.5%、13.2%;干物质积累量增加,其中甜菜增加2.3%~4.1%、3.1%~4.8%,大豆增加7.8%~10.0%、10.4%~13.6%;3)深松、亚表层耕作处理与对照相比,其中甜菜增产8.5%、12.6%;大豆增产5.0%、6.1%;深松及亚表层耕作改土处理分别比对照增收1003.3、1454.4元/hm2,其中收益大小为亚表层耕作处理深松处理对照。可见,采用ES-210深松犁及心土耕作犁深耕改土,改变了土壤耕层构造,起到扩库增容的效果;改善了作物根系生长环境,提高了作物产量,为今后农业耕作机械的发展提供了技术支撑。  相似文献   

5.
Abstract

The impact of conservation tillage, crop rotation, and cover cropping on soil‐quality indicators was evaluated in a long‐term experiment for cotton. Compared to conventional‐tillage cotton, other treatments had 3.4 to 7.7 Mg ha?1 more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0‐ to 3‐and 3‐ to 6‐cm depths, respectively. Tillage had a strongth influence on POMc within the 0‐ to 3‐cm depth, but cropping intensity and cover crop did not affect POMc. A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg?1 within depth of 0–3 and 12–24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no‐tillage cotton double‐cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.  相似文献   

6.
Sugarcane is the main crop in Kitadaito Island, Okinawa, Japan. The average yield in Kitadaito Island for the past 30 years (1985–2015) was 44 Mg ha?1, 31% lower than that (64 Mg ha?1) in Okinawa Prefecture. Among the reasons for the low sugarcane productivity in Kitadaito Island, the effects of soil and cultivation factors have not been sufficiently studied. The objectives of this study were i) to evaluate the effects of soil physical and chemical properties and cultivation factors on sugarcane yield and sugar content in 50 fields of Kitadaito Island, and ii) to clarify factors affecting the sugarcane yield and sugar content. Statistical analysis of classification and regression trees (CART) showed that the sugarcane yield was low in fields with low available nitrogen (less than 16.5 mg kg?1) and with shallow plow layer depth (less than 29 cm). The soil available nitrogen had a significant positive correlation with soil humus (r = 0.39, P < 0.05). Two-times of subsoiling in the field before planting and during growing periods resulted in the significant increase of the depth of plow layer, compared to the fields with single and no subsoiling. A high sugar content was obtained in fields with exchangeable Mg more than 3.8 cmolc kg?1 and pH(H2O) less than 7.2. Our study therefore concluded that soil management practices for sugarcane production in Kitadaito Island should primarily be focused on available nitrogen, plow layer depth, and soil exchangeable Mg and pH.  相似文献   

7.
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8.
该文选用华北平原壤土区常用的深松旋耕联合作业机作为试验设备,分析深松、旋耕作业次序对其作业质量及功耗的影响。运用离散元仿真分析结果表明,旋耕深松作业次序比深松旋耕作业次序的工作紧凑、刀辊受力均匀。随着作业深度的增加,深松旋耕作业次序作用的深层土壤较多。建立以旋耕深度、深松深度为因素,以2种作业次序功耗为指标的回归方程综合分析得出,作业深度较浅时,深松旋耕作业次序功耗、地表平整度、植被覆盖率优于旋耕深松作业次序;作业深度较大时,旋耕深松作业次序功耗明显小于深松旋耕作业次序,且两者作业质量差异不显著。田间试验表明,离散元仿真建立的2种作业次序作业深度与作业功耗的回归方程及测量的地表平整度、土壤膨松度及植被埋覆率基本能真实反映田间作业情况。  相似文献   

9.
【目的】研究耕作模式对旱地雨养夏玉米–冬小麦(以下简称玉–麦)两熟体系生产力的影响,并对深松、翻耕在轮耕模式中的作用进行评价。【方法】定位试验于2015—2021年在中国农业科学院洛阳旱农试验基地进行。设置夏免耕秋免耕(SNAN)、夏深松秋免耕(SSAN)、夏免耕秋3年免耕1年翻耕(SNA3N1P)、夏深松秋3年免耕1年翻耕(SSA3N1P)和传统夏秋季均翻耕(CT) 5种耕作模式,调查了玉米、小麦的产量和水分利用效率,2020年测定了玉米收获期0—40 cm土层土壤容重、养分含量和酶活性,以及2019—2020年度小麦收获期0—380 cm土层的硝态氮累积量。【结果】1)与CT处理相比,SNAN、SSAN、SNA3N1P和SSA3N1P处理的玉米、小麦和周年产量分别显著提高了28.4%～33.5%、23.7%～25.0%和27.1%～30.3%,水分利用效率分别显著提高了19.6%～39.2%、20.2%～29.3%和29.5%～34.5%,0—5 cm和20—40 cm土层土壤容重显著降低,0—5 cm土层的有机质含量以及0—40 cm多数土层的全氮、有效磷、速效钾含量和脲酶、蔗糖...  相似文献   

10.
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   

11.
Continuous conventional tillage can cause serious soil degradation in rain‐fed agriculture, which reduces crop productivity. Adopting suitable tillage practices is very important for improving the soil and increasing crop productivity. Between 2007 and 2010, a 3‐year field study was conducted in semi‐arid areas of southern Ningxia, China, to determine the effects of rotational tillage practices on bulk density, soil aggregate, organic carbon concentration and crop yields. Three tillage treatments were tested: no‐tillage the first and third year and subsoiling the second year (NT/ST/NT); subsoiling the first and third year and no‐tillage the second year (ST/NT/ST); and conventional tillage each year (CT). A conventional tillage treatment was used as the control. Under the rotational tillage treatments, the mean soil bulk density at a depth of 0–60 cm was significantly (P < 0.05) decreased by 4.9% compared with CT, and with the best effect under ST/NT/ST. The soil organic carbon (SOC) concentration and aggregate size fractions and stability at 0–40 cm depth were significantly (P < 0.05) increased in rotational tillage treatments when compared with the conventional tillage, and the ST/NT/ST treatment produced the highest increases. Significant differences were detected in the SOC concentration in 2 to 0.25–mm size fractions at 0–30 cm depth between rotational tillage treatments and conventional tillage. Biomass and grain yield with the rotational tillage practices were significantly positively influenced over 3 years, and ST/NT/ST produced the highest average crop yields among the three treatments. Therefore, it was concluded that the application of rotational tillage with subsoiling every 2 years and no‐tillage every other year (ST/NT/ST) should be of benefit in promoting the development of dryland farming in semi‐arid areas of northwest China.  相似文献   

12.
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   

13.
深松35 cm可改善潮棕壤理化性质并提高小麦和玉米产量   总被引：5，自引：2，他引：3  
【目的】我国传统耕作深度一般为20 cm,长期不变的翻耕深度降低耕层厚度,增加了犁底层厚度,影响作物的生长。研究小麦—玉米一年两季的种植模式下深松耕作的效果,为大田耕作管理提供技术支持。【方法】田间试验在山东烟台潮棕壤上进行。设计4个耕作处理,分别为常规翻耕20 cm (CK)、深松30 cm、深松35 cm、深松40 cm。小麦播种前进行耕作处理,所有处理均结合耕作一次性基施腐殖酸复合肥 (N–P2O5–K2O=18–10–12) 1125 kg/hm2。玉米免耕,在拔节期追施一次化肥。于小麦、玉米收获期取0—10 cm、10—20 cm、20—30 cm及30—40 cm土层土壤样品,测定土壤速效养分含量与土壤容重,计算三相比,并调查小麦、玉米产量。【结果】与CK相比,深松30 cm、35 cm、40 cm小麦季分别增产10.9%、15.3%和15.5%,玉米季分别增产12.0%、14.9%和9.4%(P < 0.05);10—40 cm土层土壤容重降低了0.03～0.18 g/cm3。其中,小麦季0—10 cm土层中CK处理土壤容重显著低于各深松处理,深松35 cm处理0—10 cm与10—20 cm土层土壤容重显著高于其他各处理;玉米季0—10 cm与10—20 cm土层土壤容重最低的处理为深松35 cm,且显著低于其他处理。小麦季深松30 cm处理各土层土壤三相比 (R值) 在13.2～15.9之间,总体最小,玉米季则以深松40 cm三相比值总体最小,在6.03～8.81之间。深松处理增加了20—40 cm土层有效养分含量,其中深松35 cm处理的20—40 cm土层有效磷和速效氮含量增加最为明显,分别为0.56～37.4 mg/kg与31.9～77.8 mg/kg;速效钾各土层的增加则以深松30 cm最为显著,为24.3～100 mg/kg;有机质含量以深松40 cm增加量最大,为0.95～0.69 g/kg。【结论】深松耕作可显著降低当季土壤容重,增加当季与下一季作物产量,提高土壤耕层以下20—40 cm土层的养分有效性,综合各机械能耗与耕作效果,以深松35 cm最佳。  相似文献   

14.
Crop rotation and cultural practice may influence soil residual N available for environmental loss due to crop N uptake and N immobilization. We evaluated the effects of stacked vs . alternate‐year crop rotations and cultural practices on soil residual N (NH4‐N and NO3‐N contents) at the 0–125 cm depth, annualized crop N uptake, and N balance from 2005 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)–durum–canola (Brassica napus L.)–pea (Pisum sativum L.) (DDCP) and durum–durum–flax (Linum usitatissimum L.)–pea (DDFP). Alternate‐year rotations were durum–canola–durum–pea (DCDP) and durum–flax–durum–pea (DFDP). Both of these are legume‐based rotations because they contain legume (pea) in the crop rotation. A continuous durum (CD) was also included for comparison. Cultural practices were traditional (conventional tillage, recommended seeding rate, broadcast N fertilization, and reduced stubble height) and improved (no‐tillage, increased seeding rate, banded N fertilization, and increased stubble height) systems. The amount of N fertilizer applied to each crop in the rotation was adjusted to soil NO3‐N content to a depth of 60 cm observed in the autumn of the previous year. Compared with other crop rotations, annualized crop biomass N was greater with DCDP and DDCP in 2007 and 2009, but was greater with DDFP than DCDP in 2011. Annualized grain N was greater with DCDP than CD, DFDP, and DDFP and greater in the improved than the traditional practice in 2010 and 2011. Soil NH4‐N content was greater with CD than other crop rotations in the traditional practice at 0–5 cm, but was greater with DDCP than CD and DDFP in the improved practice at 50–88 cm. Soil NO3‐N content was greater with CD than other crop rotations at 5–10 cm, but was greater with CD and DFDP than DCDP and DDCP at 10–20, 88–125, and 0–125 cm. Nitrate‐N content at 88–125 and 0–125 cm was also greater in the traditional than the improved practice. Nitrogen balance based on the difference between N inputs and outputs was greater with crop rotations than CD. Increased N fertilization rate increased soil residual N with CD, but legume N fixation increased N balance with crop rotations. Legume‐based crop rotations (all rotations except CD) reduced N input and soil residual N available for environmental loss, especially in the improved practice, by increasing crop N uptake and N immobilization compared with non‐legume monocrop.  相似文献   

15.
[目的]研究黑龙江省西部不同土壤耕作方式对玉米产量及土壤性状的影响,为该地区农业生产提供参考。[方法]比较常规耕作、旋耕、翻耕、深翻和超深翻耕作对玉米产量和土壤物理特性的影响。[结果]翻耕和超深翻耕作增加了土壤含水量和田间持水量,降低了耕层土壤渗透速率、土壤容重和土壤紧实度,但是增加犁底层土壤渗透速率、土壤容重和土壤紧实度。翻耕、深翻和超深翻处理耕层土壤三相结构距离(STPSD)和土壤结构指数(GSSI)较好;翻耕、深翻和超深翻处理显著降低犁底层土壤的GSSI,增加STPSD;旋耕处理没有显著影响犁底层土壤GSSI和STPSD。与常规耕作处理相比,翻耕和超深翻分别增加玉米产量7.6%和6.0%。翻耕比超深翻玉米产量高10.9%。深翻处理玉米产量为5.58t/hm2,比常规耕作减产8.1%。[结论]在不完全打破犁底层情况下,在黑龙江西部地区翻耕是比较理想的耕作方式。  相似文献   

16.
The soil tillage system affects incorporation of crop residues and may influence organic matter dynamics. A study was carried out in five 15–20 year old tillage experiments on soils with a clay content ranging from 72 to 521 g kg−1. The main objective was to quantify the influence of tillage depth on total content of soil organic carbon and its distribution by depth. Some soil physical properties were also determined. The experiments were part of a series of field experiments all over Sweden with the objective of producing a basis to advise farmers on optimal depths and methods of primary tillage under various conditions. Before the experimental period, all sites had been mouldboard ploughed annually for many years to a depth of 23–25 cm. Treatments included primary tillage to 24–29 cm depth by mouldboard plough (deep tillage) and to 12–15 cm by field cultivator or mouldboard plough (shallow tillage). Dry bulk density, degree of compactness and penetration resistance profiles clearly reflected the depth of primary tillage and substantially increased below that depth. Compared to deep tillage, shallow tillage increased the concentration of organic carbon in the surface layer but decreased it in deeper layers. Total quantity of soil organic carbon and carbon–nitrogen ratio were unaffected by the tillage depth. Thus, a reduction of the tillage depth from about 25 cm to half of that depth would appear to have no significant effect on the global carbon cycle.  相似文献   

17.
Field experiments (established in autumn 1979, with monoculture barley from 1980 to 1990 and barley/wheat–canola–triticale–pea rotation from 1991 to 2008) were conducted on two contrasting soil types (Gray Luvisol [Typic Haplocryalf] loam soil at Breton; Black Chernozem [Albic Agricryoll] silty clay loam soil at Ellerslie) in north-central Alberta, Canada, to determine the influence of tillage (zero tillage and conventional tillage), straw management (straw removed [SRem] and straw retained [SRet]), and N fertilizer rate (0, 50 and 100 kg N ha?1in SRet, and only 0 kg N ha?1in SRem plots) on seed yield, straw yield, total N uptake in seed + straw (1991–2008), and N balance sheet (1980–2008). The N fertilizer urea was midrow-banded under both tillage systems in the 1991 to 2008 period. There was a considerable increase in seed yield, straw yield, and total N uptake in seed + straw with increasing N rate up to 100 kg N ha?1 under both tillage systems. On the average, conventional tillage produced greater seed yield (by 279 kg ha?1), straw yield (by 252 kg ha?1), and total N uptake in seed + straw (by 6.0 kg N ha?1) than zero tillage, but the differences were greater at Breton than Ellerslie. Compared to straw removal treatment, seed yield, straw yield, and total N uptake in seed + straw tended to be greater with straw retained at the zero-N rate used in the study. The amounts of applied N unaccounted for over the 1980 to 2008 period ranged from 1114 to 1846 kg N ha?1 at Breton and 845 to 1665 kg N ha?1 at Ellerslie, suggesting a great potential for N loss from the soil-plant system through denitrification, and N immobilization from the soil mineral N pool. In conclusion, crop yield and N uptake were lower under zero tillage than conventional, and long-term retention of straw suggests some gradual improvement in soil productivity.  相似文献   

18.
In Vertisols of central India erratic rainfall and prevalence of drought during crop growth, low infiltration rates and the consequent ponding of water at the surface during the critical growth stages are suggested as possible reasons responsible for poor yields (<1 t ha−1) of soybean (Glycine max (L.) Merr.). Ameliorative tillage practices particularly deep tillage (subsoiling with chisel plough) can improve the water storage of soil by facilitating infiltration, which may help in minimizing water stress in this type of soil. In a 3-year field experiment (2000–2002) carried out in a Vertisol during wet seasons at Bhopal, Madhya Pradesh, India, we determined infiltration rate, root length and mass densities, water use efficiency and productivity of rainfed soybean under three tillage treatments consisting of conventional tillage (two tillage by sweep cultivator for topsoil tillage) (S1), conventional tillage + subsoiling in alternate years using chisel plough (S2), and conventional tillage + subsoiling in every year (S3) as main plot. The subplot consisted of three nutrient treatments, viz., 0% NPK (N0), 100% NPK (N1) and 100% NPK + farmyard manure (FYM) at 4 t ha−1 (N2). S3 registered a significantly lower soil penetration resistance by 22%, 28% and 20%, respectively, at the 17.5, 24.5 and 31.5 cm depths over S1 and the corresponding decrease over S2 were 17%, 19% and 13%, respectively. Bulk density after 15 days of tillage operation was significantly low in subsurface (15–30 cm depth) in S3 (1.39 mg m−3) followed by S2 (1.41 mg m−3) and S1 (1.58 mg m−3). Root length density (RLD) and root mass density (RMD) of soybean at 0–15 cm soil depth were greater following subsoiling in every year. S3 recorded significantly greater RLD (1.04 cm cm−3) over S2 (0.92 cm cm−3) and S1 (0.65 cm cm−3) at 15–30 cm depth under this study. The basic infiltration rate was greater after subsoiling in every year (5.65 cm h−1) in relation to conventional tillage (1.84 cm h−1). Similar trend was also observed in water storage characteristics (0–90 cm depth) of the soil profile. The faster infiltration rate and water storage of the profile facilitated higher grain yield and enhanced water use efficiency for soybean under subsoiling than conventional tillage. S3 registered significantly higher water use efficiency (17 kg ha−1 cm−1) over S2 (16 kg ha−1 cm−1) and S1 (14 kg ha−1 cm−1). On an average subsoiling recorded 20% higher grain yield of soybean over conventional tillage but the yield did not vary significantly due to S3 and S2. Combined application of 100% NPK and 4 t farmyard manure (FYM) ha−1 in N2 resulted in a larger RLD, RMD, grain yield and water use efficiency than N1 or the control (N0). N2 registered significantly higher yield of soybean (1517 kg ha−1) over purely inorganic (N1) (1392 kg ha−1) and control (N0) (898 kg ha−1). The study indicated that in Vertisols, enhanced productivity of soybean can be achieved by subsoiling in alternate years and integrated with the use of 100% NPK (30 kg N, 26 kg P and 25 kg K) and 4 t FYM ha−1.  相似文献   

19.
The objective of this study was to examine the effect of nitrogen-fertilization management on soil nutrient distribution at different soil depths under conventional tillage in dryland rain-fed environment. Two nitrogen (N) application methods (single application with all N applied at planting and split application with 35 kg N ha?1 applied at planting and remaining N applied at V6 growth stage) and five N rates (0, 45, 90, 135, and 180 kg N ha?1) were utilized. Increasing soil depth decreased extractable phosphorus (P), potassium (K), and calcium (Ca) contents in the soil. The nitrate (NO3)-N concentration in deeper soil was similar to the top layer as N fertilization was greater than 90 kg N ha?1. It suggests that N application should be less than 90 kg ha?1 to reduce the movement of excess N to deep soil layers and cause a potential negative impact on environment in this area.  相似文献   

20.
Soil organic matter (SOM) is considered an important indicator of soil quality, which can be impacted by crop production practices such as tillage. In this study, two long‐term tillage regimes (conventional tillage [CT] and no tillage [NT], conducted for 36 years) were compared in continuous sorghum production in a sub‐tropical environment in southeast Texas. The positive effects of long‐term NT practice were more conspicuous at the soil surface compared with the deeper soil profiles. The SOC was greater (1.5 t C ha?1 greater) in the NT system compared with the CT system. Results from an incubation study indicate that the rate of C‐min at 0–5 cm soil depth was significantly greater (164 μg of CO2–C g?1 of soil greater) in NT than that of CT, but this trend was reversed at 10–20 cm depth wherein the C‐min rates were 106 μg of CO2–C g?1 of soil greater in CT compared with NT, which is likely because of soil disturbance during the study. Soil cumulative CO2‐C emissions were greater in the CT system (7.28 g m?2) than in the NT system (5.19 g m?2), which is primarily attributed to high soil temperature conditions in the CT system. Sorghum grain yield however was not influenced by the differences in SOC content in this long‐term experiment. Overall, the present study found that long‐term conservation tillage improved SOC stock and reduced carbon loss, thus had a positive impact on soil health and sustainability.  相似文献   

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