玉米减量施肥研究

在吉林通化市长年高施肥量(N180kg／hm^2，P2O5 70kg／hm^2)的玉米栽培区，实行减量施肥效果明显。1999年在暗棕壤上试验，用氮量降低23kg／hm^2(实际用氮量150kg／hm^2)，比高施氮量的增产10％左右，2001～2002年分别在冲积土和白浆土上试验，用氮量降低36kg／hm^2(实际用氮量144kg／hm^2)，比高施氮量的分别增产5．65％、2．56％。1995年在白浆土和暗棕壤上试验，施P205量在36．6～91．8kg／hm^2间，形成的玉米产量没有本质上的差异，即多施磷和少施磷的效果是一样的。据此，吉林省东部地区玉米施氮量应由目前180kg／hm^2，减为140～150kg／hm^2，施P2O5量由目前70kg／hm^2，减为35～45kg／hm^2。     

缓释氮肥运筹对稻麦轮作周年作物产量和氮肥利用率的影响

【目的】稻麦轮作是我国一种重要的农业种植模式。缓/控释肥作为高效兼环境友好的肥料类型,在多种作物单季种植上具有增产和提高肥效的作用,但是缓释肥在周年轮作体系中的肥效研究鲜有报道。因此研究稻麦轮作体系中的肥料施用模式,有助于提高稻麦产量,降低化肥用量,提高化肥利用率。【方法】本文通过稻麦轮作两周年四季作物的田间小区试验,以不施氮和习惯施氮为对照,研究了4种不同缓释肥减氮处理[进口树脂包膜尿素减氮24.3%、 国产硫包衣尿素减氮24.3%、 国产尿素加NAM(长效氮肥添加剂)减氮24.3%和国产尿素加NAM减氮10.8%]对水稻和小麦产量、 氮肥利用率、 第二周年稻麦收获后土壤养分含量和两周年土壤氮养分表观平衡的影响。【结果】与不施氮对照相比,所有施氮处理均提高了两周年稻麦4季作物产量,习惯施氮增产幅度最高,小麦的氮肥增产效果总体高于水稻,第二周年高于第一周年; 与当地习惯施氮量相比,所有的缓释氮肥减氮24.3%或10.8%处理均无显著降低两季小麦产量,进口树脂包膜尿素减氮24.3%处理和国产尿素加NAM减氮10.8%处理也无显著降低两季水稻产量,但是国产尿素加NAM减氮24.3%处理显著降低了第二季水稻产量,国产硫包衣尿素减氮24.3%显著降低了两季水稻产量; 与当地习惯施氮量相比,4个缓释氮肥减氮处理均提高了第一和第二周年氮肥利用率,显著降低了两周年稻田土壤养分氮盈余量,其中国产尿素加NAM减氮24.3%处理氮肥利用率较高,同时土壤氮盈余量较少,说明缓释氮肥减量在提高肥料利用率和降低氮的环境效应上具有一致的优势; 不同缓释氮肥对土壤养分含量的影响无明显规律性。【结论】在目前稻麦轮作体系中,缓释氮肥减施对小麦产量具有较好的稳定效果,但是个别缓释氮肥减施对水稻有减产风险,有必要依据稻田土壤氮素转化特点,研制水稻专用缓释氮肥,适当降低水稻季缓释氮肥的施用量。     

稻麦轮作周年氮磷运筹对作物产量和土壤养分含量的影响

通过稻麦轮作两周年四季作物的田间小区试验,研究了氮磷减量及磷肥运筹对水稻、小麦产量和第二周年稻麦收获后土壤养分含量的影响。结果表明:在习惯施肥的基础上减少氮肥用量10.8%和磷肥25.0%,对第一周年小麦、水稻产量和第二周年小麦产量没有显著影响,却显著降低了第二周年水稻产量;氮磷减量处理显著降低了第二周年水稻收获后土壤有效磷的含量,而对土壤pH值、有机质、碱解氮和速效钾含量没有显著影响;在氮磷减量条件下,小麦、水稻两季均施用磷肥与小麦一季集中施用磷肥进行比较,二者之间两周年四季作物产量没有显著差异。据此,建议稻麦轮作区实施"氮肥适当减量、磷肥隔年集中施用在小麦季"的氮磷施肥原则,可以达到降低肥料用量和劳动力投入,同时保证产量的目的。     

稻麦轮作过程中稻草机械还田利用技术研究

本文针对农村稻草资源的还田利用问题,对稻麦轮作过程中,采用机械方法进行稻草还田的最适方式、用量、以及在稻套麦轻型栽培条件下,提高稻草还田效果的配套技术进行了研究,现将试验情况报告如下：     

均衡施肥对滩涂盐碱农田稻麦轮作系统土壤养分与作物生长和养分吸收的影响

以耐盐小麦和水稻为材料,研究了滩涂盐碱地养分均衡对轮作稻麦生长和养分吸收的影响。试验设不施肥(CK)、常规施肥(TF)、中量元素肥料+常规施肥(TS)、螯合态微量元素肥+常规施肥(TM)和中量元素肥料+螯合态微量元素肥料+常规施肥(TSM)5个处理。结果表明:(1)大量元素方面,小麦季TSM处理显著提高了土壤碱解氮和速效钾水平,分别较TF处理增长23.22%和7.10%;水稻季TSM处理土壤有效磷和速效钾显著提高,较TF处理分别提高19.78%和7.44%;稻麦轮作体系均衡施肥(TSM)显著降低了土壤含盐量,由3.09 g/kg土降为1.88 g/kg土;(2)中微量元素方面,小麦季TSM处理显著提高了土壤S、Fe含量,分别较TF处理增长了196.3%、13.75%;水稻季TSM处理土壤Si、Ca、Fe、Mn含量较TF处理显著提高,分别增加了27.42%、11.60%、12.05%、16.20%;(3)TSM处理小麦和水稻生物量明显提高,较TF处理增长了19.47%和20.12%,且TSM处理较TF处理作物养分含量显著提高(P<0.05);(4)施肥处理明显提高了稻麦植株中各营养...     

江苏泰州市稻?麦轮作体系土壤氮磷钾养分平衡状况

【目的】本文旨在评价泰州市稻麦轮作耕地养分平衡情况,为推进耕地质量提升、减轻农业面源污染提供理论依据,对今后耕地质量建设与保护工作提出对策和建议。【方法】以江苏省耕地质量监测数据库中2012—2017年泰州市20个省级耕地质量监测点的肥料投入和作物产量数据为基础,根据不同作物产量与养分吸收的关系测算出各监测点养分投入和吸收数据,并据此计算养分平衡率,利用SPSS软件对不同农区、不同年度的上述数据进行统计分析。【结果】该市近年来氮肥投入总量基本稳定,磷肥、钾肥投入逐年上升,2017年增加显著。不同农区、不同年度的作物产量间没有显著性差异,年均产量为小麦籽粒4705.5 kg/hm2,小麦茎杆5220.3 kg/hm2,水稻籽粒7049.2 kg/hm2,水稻茎杆7511.5 kg/hm2。全市耕地土壤氮肥、磷肥盈余,钾肥亏损。氮肥年均盈余率为117.53%,磷肥年均盈余率为24.19%,钾肥年均亏缺率为?49.04%。土壤氮肥盈余率较为稳定,年度间变化不显著。磷肥盈余率呈现逐年上升趋势,但没有显著差异。钾肥亏缺率呈现逐年下降趋势,2017年钾肥亏缺率为?36.19%,显著低于其他年份。各区土壤养分盈亏情况均为氮、磷盈余,钾亏损。氮肥以里下河区盈余率最高,为139.53%,显著高于高沙土区(106.27%)和沿江区(106.71%)。磷肥盈亏率各区之间没有显著性差异。钾肥以高沙土区亏缺率最低,为?40.96%,显著低于里下河区(?57.73%)和沿江区(?48.19%)。【结论】泰州市近年来肥料投入整体符合“减氮控磷、补施钾肥”的原则,有效保证了当地作物的稳定高产,但各农区土壤养分盈亏状况不同,氮磷钾养分盈亏变化趋势也不完全相同。因此,应根据各区具体盈余及变化,调整氮磷钾施肥量。     

玉米减量施肥研究

在吉林通化市长年高施肥量(N180kg/hm2,P2O570kg/hm2)的玉米栽培区,实行减量施肥效果明显。1999年在暗棕壤上试验,用氮量降低23kg/hm2(实际用氮量150kg/hm2),比高施氮量的增产10%左右,2001～2002年分别在冲积土和白浆土上试验,用氮量降低36kg/hm2(实际用氮量144kg/hm2),比高施氮量的分别增产5 65%、2 56%。1995年在白浆土和暗棕壤上试验,施P2O5量在36 6～91 8kg/hm2间,形成的玉米产量没有本质上的差异,即多施磷和少施磷的效果是一样的。据此,吉林省东部地区玉米施氮量应由目前180kg/hm2,减为140～150kg/hm2,施P2O5量由目前70kg/hm2,减为35～45kg/hm2。     

施肥方式对稻麦轮作土壤团聚体分布的影响

土壤是人类赖以生存的重要资源,团聚体作为土壤结构的基础单元,不仅提高土壤肥力、调节养分的生物有效性,而且增强土壤抗侵蚀能力。通过6年试验,研究了不施肥(CK)、常规施肥(CF)、秸秆+缓释肥(SRF)和有机无机混施(OCF)4种施肥方式对土壤养分含量及各粒级团聚体分布的影响,为揭示施肥措施对土壤地力形成演变的影响机制提供理论基础。结果表明:SRF和OCF处理0—20,20—40 cm土层土壤的SOC含量较CF显著增加10.06%,19.23%和9.84%,16.79%;3种施肥处理0—20,20—40 cm土层的TN差异不显著,但均高于CK处理;OCF处理中0—20 cm土层的C/N比较CF增加16.44%(p0.05)。SRF处理较CK显著提高了0—20 cm土层R_(0.25)(10.93%);20—40 cm土层,OCF处理中R_(0.25)显著高于其他3个处理,分别高出32.62%(CK),19.75%(CF),19.44%(SRF)(p0.05)。相比CF处理,SRF和OCF提高了0—20,20—40 cm土层的平均质量直径MWD(1.54%～16.92%,2.17%～28.26%)和平均几何直径GMD(5.88%～14.71%,13.04%～39.13%),降低了分形维数D(1.11%～2.09%,4.99%～5.44%),且OCF处理更为显著(p0.05)。可见,秸秆+缓释肥和有机无机混施处理均有利于土壤肥力提升,且后者效果更为显著。MWD和GMD与土壤SOC和TN的相关性较高,均适合用于揭示团聚体与土壤总有机碳、总氮含量之间的关系;但分形维数D与之无显著相关性关系。     

不同施肥和秸秆还田措施对稻麦轮作系统碳氮流失的影响

过量施肥和秸秆的处理问题一直是制约我国农业生态可持续发展的阻碍,并因此产生了诸多环境问题。采用DNDC模型对减量化施肥和秸秆还田措施下稻麦轮作系统中碳氮的迁移转化过程进行模拟,从而筛选适用于上海地区稻麦轮作系统中的最佳农田管理措施。结果表明:减量化施肥与秸秆还田均能显著影响稻麦轮作系统的氮素流失、温室气体排放和土壤碳储量变化。75%CK+SR处理即减量25%施肥量同时采用秸秆还田是适用于上海地区稻麦轮作系统中的最佳农田管理措施,能够在获得最佳水稻产量的同时有效减少41.67%的氮素流失量和51.85%的N_2O排放量。虽然秸秆还田会增加稻麦轮作系统的CH_4排放量,但同时也能显著增加土壤的碳储量。减量化施肥50%的处理(50%CK和50%CK+SR)则会导致水稻减产3.06%~9.90%。与目前上海地区传统的田间管理措施CK相比,75%CK+SR能够有效改善稻麦轮作系统的生态环境效益。研究结果为我国稻麦轮作系统碳氮流失的控制提供了参考。     

用原状土柱研究太湖地区稻麦轮作农田养分淋溶量

采用原状模拟土柱,对太湖地区不同施肥水平下稻麦轮作农田NH4 -N、N03--N 和TP的淋溶量进行了研究.初步结果表明:麦田NH4 -N、NO3--N 和TP的淋溶量分别为0.36～0.64、2.74-16.42和0.05-0.19kg/hm2,各占化肥施用量的0.2%～0.4%、4.8%～8.1%和0.2%～0.7%;稻田NH4 -N、N03--N和TP的淋溶量分别为0.36～1.04、0.86～3.01和0.24～1.17kg/hm2,各占化肥施用量的0.2%～0.4%、0.6%～1.7%和0.8%～8.2%.猪粪能增加养分淋溶量,尤其显著促进了P素向下迁移;秸秆减少麦季土壤无机N的淋溶损失.     

Zinc fertilization in rice-wheat cropping system under upland calcareous soil

Zinc (Zn) fertilization is important for Zn crop biofortification as well as increasing yields, thus proper Zn recommendations for soil application is needed for Zn deficient soils. The effectiveness of Zn applications was evaluated in different combinations of rates (2.5, 5.0, 7.5, and 10.0?kg?ha^?1 per year) and frequencies (initial, alternate, and every year) in rice (Oriza sativa L.) – wheat (Triticum aestivum L.) cropping system in a Zn-deficient upland calcareous soil in the fourth year. Zn applications to rice at 7.5 and 10?kg?ha^?1 of alternate year and 5.0 to 10?kg?ha^?1 of every year had the highest rice equivalent yield as compared to no-Zn treatment. Hence, Zn application to rice at 7.5?kg?ha^?1 at alternate years is the lowest rate at which highest rice equivalent yield of rice-wheat cropping system can be obtained.     

采用土壤质量指数评估施肥对集约型稻麦轮作系统中土壤物理性质的影响

Soil quality assessment has been suggested as an effective tool for evaluating sustainability of soil and crop management practices.The objective of this study was to develop a sensitive soil quality index(SQI) based on bulk density(BD),water-holding capacity(WHC),water-stable aggregates(WSA),aggregate mean weight diameter(AMWD),total organic C(TOC) and C input to evaluate the important rice-wheat cropping system on an Inceptisol in India.A long-term experiment has been conducted for 18 years at the Indian Council of Agricultural Research-Indian Institute of Farming Systems Research,Modipuram,India.The treatments selected for this study were comprised of a no-fertilizer control and N,P and K fertilizers(NPK) combined with Zn and S fertilizers(NPK+ Zn+S),farmyard manure(NPK+FYM),green gram residues(NPK+GR) and cereal residues(NPK+CR),laid out in a randomized complete block design with three replications.Soil samples were collected and analyzed for BD,WHC,WSA and TOC.Correlation analysis revealed that both rice and wheat yields signi?cantly increased with the increases in AMWD,TOC and C input,but decreased with the increase in BD.The SQI values were then generated based on regression analysis of BD,WSA,AMWD,TOC and C input with rice and wheat yields for the 0–15 and 15–30 cm soil layers,respectively.Regression analyses between crop yields and SQI values showed a quadratic type of relation with the coeffcient of determination(R~2) varying from 0.78 to 0.89.With regard to soil sustainability,applying crop residues to both rice and wheat could maintain soil quality for a longer period,whereas the highest yields of both the crops were recorded in the NPK+Zn+S treatment.The regression equations developed in this study could be used to monitor soil quality in a subhumid tropical rice-wheat cropping system.     

Integrated assessment of diversification of rice-wheat cropping system in Indo-Gangetic plain

Diversification of rice-wheat cropping system may improve the productivity and sustainability of agricultural production in the Indo-Gangetic plane region (IGPR), but the choice of alternative sequences to be used requires integrated assessment of various crop sequences. A long-term field experiment was initiated during 2000–01 on sandy loam soil at Banaras Hindu University, Varanasi, India to assess 10 rice-based cropping sequences – rice-wheat, rice-chickpea, rice-wheat-green gram, rice-wheat-Sesbania (green manure), rice-mustard-green gram, rice-lentil-cowpea (fodder), rice-pea, rice-lentil + mustard (3:1)-cowpea (fodder), rice-maize (cob) + vegetable pea (1:1)-cowpea (fodder) and rice-potato-green gram in randomized block design with four replications. The data contained in this paper are for the year 2002–03 and 2003–04. Substitution of rice-wheat with 300% intensity cropping sequences particularly with rice-potato-green gram resulted in maximum production cost but gave the highest system productivity, net return, benefit:cost ratio, production efficiency, profitability and energy productivity. Inclusion of summer grain/fodder legume or Sesbania for green manuring improved the content of soil organic matter. The soil P status was positively affected in all the sequences and particularly those with summer crops. Decline in soil available K in all the sequences indicated inadequacy of present recommended rate of fertilizer K to all the component crops in different sequences.     

Microbial community response to soil solarization in Nepal's rice-wheat cropping system

The Indo-Gangetic Plains of South Asia support 13.5 million hectares of rice-wheat cropping systems, which currently feed over one billion people. Intensified agriculture has resulted in a more than two-fold increase in rice and wheat yields since the 1970s; however, this continuous cropping has also exacerbated weed, pest and disease problems. Soil solarization is an accessible, low-risk management practice for small-holder farmers that has ameliorated these problems in some settings and has the potential to dramatically improve yields. Field trials were conducted at two sites in Nepal to test whether soil solarization: (i) had a lasting effect on soil bacterial, fungal and nematode communities; (ii) altered the rhizosphere communities of rice nursery seedlings and (iii) improved crop growth and yield in the rice-wheat cropping system. Rice seedlings were grown in nursery plots that were solarized for 28 days or left untreated and were transplanted to field plots that were also either solarized for 28 days or not in a randomized complete block design with four replications. Rice was grown to maturity and harvested, followed by a complete wheat cropping cycle. Solarization of main field plots increased counts of fungal propagules and decreased root galling and nematode counts and decreased weed biomass. Terminal restriction fragment length polymorphism (T-RFLP) analyses of extracted soil DNA revealed significant shifts in fungal community composition following soil solarization, which was sustained throughout the entire rice cropping cycle at both field sites. The bacterial community composition was similarly affected, but at only one of the two sites. Despite the observed changes in soil microbial community composition over more than one cropping period, solarization had no impact on crop productivity at either site. Nevertheless, such changes in soil microbial communities in response to solarization may be responsible for increased yields observed at other sites with greater pathogen pressure. This practice has shown promising results in many farmers’ fields in South Asia, but further elucidation of the mechanisms by which solarization increases productivity is needed.     

Puddling and N management effects on crop response in a rice-wheat cropping system

Coarse-textured soils are puddled to reduce high percolation losses of irrigation water under rice (Oryza sativa L.). This practice, however, reduces yield of succeeding wheat (Triticum aestivum L.) owing to deterioration in soil physical conditions. The 6 year field study reported in this paper evaluated the effects of puddling level and integrated N management on the development of subsurface compaction and growth and yield of rice and the following spring wheat grown in 1 year sequence on a sandy loam soil. Treatments were combinations of three puddling levels: low (one discing and one planking), medium (two discings and one planking), and high (four discings and one planking), and three nitrogen sources: (1) 120 kg N ha⁻¹ from urea, (2) 60 kg N ha⁻¹ from urea plus sesbania (Sesbania aculeata Pers.) green manure, and (3) 60 kg N ha⁻¹ from urea plus 20 Mg ha⁻¹ farmyard manure. Percolation rate decreased from 14 mm day⁻¹ with low puddling to 10 mm day⁻¹ with high puddling, with a corresponding reduction in irrigation water requirement of rice of about 20%. Bulk density profiles in the 0–30 cm soil layer showed the formation of a compact layer at 15–20 cm depth, and bulk density increased with puddling level and cropping season. The impact of organic amendments in reducing bulk density was immediate, but the rate of increase in bulk density with time was the same in all the nitrogen sources. Organic amendments did not affect percolation rate and irrigation requirement of rice. Rice yields were not significantly affected by puddling and N source treatments throughout the study period. Residual effects of treatments on wheat yield were observed from the second season onwards. Interactive effects of puddling and N source on yields of rice and succeeding wheat were not significant. Yield differences in wheat between high and low puddling were 8% and 11% during the second and the fifth cropping season, respectively. This study indicates that medium puddling was optimum, as it reduced percolation without decreasing yield of succeeding wheat.     

Soil carbon pools under long-term rice-wheat cropping system in Inceptisols of Indian Himalayas

Knowledge about soil organic carbon (SOC) stock and its allocation into different pools is important for global food and environmental security. Accordingly, an attempt is made in the present study to investigate into the dynamics of SOC pools i.e. total soil organic carbon (TOC), oxidisable organic carbon (OC) and its different fractions viz. very labile (C_VL), labile (C_L), less labile (C_LL) and non-labile (C_NL) in soils under a 26 years old long-term experiment with rice (Oryza sativa L) – wheat (Triticum aestivum L) cropping system on Inceptisols under humid agro-climatic region of India with different soil management practices (control, 100% recommended dose of NPK, and 50% recommended dose of NPK + 50% N through farmyard manure (FYM). Of the several pools analyzed, a higher proportion of C was found in labile pool followed by very labile, non-labile, and less labile ones constituting about 46, 26.5, 20 and 7.3% of the total organic C at surface soil. The NPK+FYM treatment was found to have higher SOC pools, lability index (LI), recalcitrance indices and stratification ratio as compared to others. Results indicated that balanced fertilization with inorganic and organics is important for maintaining overall sustainability of the rice-wheat system.     

江淮区域稻麦两熟制周年资源分配、利用特征

江淮区域稻麦周年两熟种植模式自然资源分配与利用特征尚不明确,限制了该区作物周年高产高效协同发展。本研究通过对江淮区域不同地区多年多点水稻-小麦种植模式高产试验数据分析,明确两熟制季节间资源分配特征、资源利用效率及其与产量的关系。结果表明：2008-2017年小麦季和周年辐射均呈降低趋势,水稻季沿淮和江淮地区呈增加趋势,沿江地区呈降低趋势;小麦季积温呈增加趋势、水稻季大部分呈降低趋势,周年沿淮地区呈增加趋势,江淮和沿江地区呈降低趋势;降雨小麦季、水稻季和周年总体呈增加趋势。江淮地区周年辐射量从北向南逐渐减少,不同种植模式间无显著差异;小麦季、水稻季辐射分配率粳稻-小麦模式分别为53.1%、51.9%,籼稻-小麦模式分别为55.0%、49.8%。江淮地区从北向南累积积温和降雨量逐渐增加,不同种植模式间无显著差异;小麦季、水稻季积温分配率粳稻-小麦模式为38.5%、67.3%,籼稻-小麦模式为40.7%、65.1%;小麦季、水稻季降雨分配率在2种模式间无显著差异,而不同地区间差异显著,沿淮地区为32.8%、70.5%,江淮地区为40.8%、64.7%,沿江地区为46.2%、57.2%。当前生产模式下,江淮区域稻麦两熟种植模式以水稻产量所占比重最高,平均为57.0%。小麦季积温生产效率沿淮地区显著高于江淮地区和沿江地区,不同种植模式间差异较小;水稻季积温生产效率不同地区不同模式间差异较小;周年积温生产效率不同地区间差异显著,且沿淮地区 > 江淮地区 > 沿江地区,不同种植模式间差异不显著。区域间作物光能生产效率差异较小,小麦季、水稻季和周年均无显著差异。不同地区降雨生产效率变异较大,小麦季、水稻季和周年均以沿淮地区大于江淮地区,显著高于沿江地区;不同种植模式间无显著差异。因此,江淮区域稻麦周年两熟资源高效利用原则应以合理配置季节间辐射为主,兼顾降雨和积温。不同地区应结合气候资源配置特点,通过合理的播栽期、周年生育期适宜的品种搭配等栽培措施将部分光热资源调配给水稻,实现产量和资源利用效率双提升。     

Optimizing phosphorus fertilization in an intensive vegetable-rice cropping system

A study was conducted in a sweet pepper-maize-rice cropping system in six farmers fields in Batac, Ilocos Norte, the Philippines, to determine the optimum P fertilizer rate for sweet pepper that will benefit the succeeding crops, maximize system-level productivity and profitability, and reduce the excessive accumulation of P in the soil. Single super phosphate was applied to sweet pepper at rates of 0, 28, 56, 84, 112, and 140 kg P ha^–1 and the succeeding crops were grown without P fertilization. Maize residue was incorporated into the soil at puddling of soil for rice. Phosphorus fertilization at 56 kg P ha^–1 and above had a residual effect on maize and rice. A reduction in the P applied to sweet pepper from 140 to 84 kg P ha^–1 reduced extractable P in the soil at rice harvest from 52 to 29 kg P ha^–1. Phosphorus applied at 111 kg P ha^–1 to sweet pepper was optimum for maximum productivity and economic returns of the sweet pepper-maize-rice cropping system. This rate of P also significantly reduced P accumulation in the soil, thereby reducing the chances of negative effects on soil nutrient balance/availability. The results suggested the need for a cropping systems approach to conserve and effectively use native and fertilizer P in the sweet pepper-rice cropping system.     

稻麦轮作区保护性耕作条件下氮肥对水稻生长发育和产量的调控效应

20062~008年在四川省广汉市开展了保护性耕作措施下水稻氮肥调控试验,设置不同秸秆还田量(0、6000、12000 kg/hm2)、施氮量水平(0、1502、10 kg/hm2)以及氮素分配比例(6∶2∶2、6∶3∶1、8∶2)。结果表明,和施N 150 kg/hm2相比,N 210 kg/hm2处理水稻分蘖力、干物质积累量、开花期的植株个体和群体质量均有升高,花后茎鞘贮藏物质的输出及光合物质积累量增加,子粒产量提高7.3%。在施N 150 kg/hm2水平和基肥∶蘖肥∶穗肥=6∶2∶2分配比例下,与旋耕无麦秸还田处理相比,免耕秸秆还田与否对水稻茎蘖消长、干物质积累及子粒产量影响较小,但花后绿叶功能期延长,光合产物积累在产量形成中所占比例增加。在施N 210 kg/hm2水平和基肥∶蘖肥∶穗肥=6∶3∶1分配比例下,免耕还田麦秸量从6000 kg/hm2增加至12000 kg/hm2,水稻分蘖力明显增强,干物质积累量增大,开花期个体和群体质量提高,单位面积穗数和穗实粒数增多,产量增加4.1%;将氮肥分配比例由6∶3∶1变为8∶2,即增加基肥用量,减少中后期的氮素供应会导致分蘖高峰后分蘖大量死亡,有效穗数降低,穗粒数减少,产量下降。以上结果说明,氮素的充分供应是保护性耕作水稻获得高产的重要前提和基础,适当提高麦秸还田量、增加中后期氮素供应,能提高氮素利用率及分蘖成穗率和结实率,利于稳产高产。     

苏南稻麦二熟区秸秆全量机械还田技术

采取田间试验和生产调查相结合的方法 ,研究总结了稻麦二熟区秸秆全量机械还田的农机农艺配套技术 ,为稻麦秸秆的农业利用和实现农业生态系统的良性循环提供了新的途径