,*, 黄敏*南方粮油作物协同创新中心 / 湖南农业大学, 湖南长沙410128Opportunities and Challenges for Crop Production in China during the Transition Period
ZOU Ying-Bin,*, HUANG Min*Southern Regional Collaborative Innovation Center for Grain and Oil Crops / Hunan Agricultural University, Changsha 410128, Hunan, China通讯作者:
收稿日期:2017-12-18接受日期:2018-03-25网络出版日期:2018-06-12
| 基金资助: |
Received:2017-12-18Accepted:2018-03-25Online:2018-06-12
| Fund supported: |
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邹应斌, 黄敏. 转型期作物生产发展的机遇与挑战[J]. 作物学报, 2018, 44(6): 791-795. doi:10.3724/SP.J.1006.2018.00791
ZOU Ying-Bin, HUANG Min.
中国以占世界7%的耕地养活了占世界22%的人口, 创造了“世界奇迹”[1]。但随着社会经济的发展, 农村出现了劳动力短缺、劳动力结构老龄化等一系列问题, 美国布朗先生担忧的“谁来养活中国人”变成了“谁来耕种中国田”[2]。中国作物生产也因此步入了由传统手工劳动为主的小规模生产向机械化、集约化、信息化程度高的适度规模化生产过渡的转型期。进一步认清转型期作物生产发展形式对促进作物生产发展和保障国家粮食安全具有重要意义。据此, 本文在阐述转型期中国作物生产特征的基础上, 分析了其发展的机遇与挑战, 展望了作物生产的研究方向, 以期为转型期中国作物生产发展提供参考。
1 转型期的作物生产特征
转型期中国作物生产具有以下3个特征。一是随着农村城镇化的推进和发展, 农村劳动力, 尤其是青壮年劳动力加速向城镇转移, 导致从事作物生产的劳动力日益缺乏, 进而促使一家一户的传统分散型种植方式正逐步向规模化、机械化、信息化的现代作物生产方式发展, 并形成了种植大户、专业合作社等多种新的作物生产组织方式。二是随着人们生活质量的提高, 以解决温饱为目标的数量高产型作物生产正逐步向质量效益型发展, 优质、高产、高效、兼顾绿色环保已成为作物生产的新目标。三是随着耕地的连年减少、人口的刚性增加, 作物生产正从单纯提高单位耕地生产率向同步提高单位耕地生产率与人均劳动生产率转变, 并将逐步形成新的作物生产发展模式。发达国家的现代作物生产主要有两种模式, 一是人少地多的美国、加拿大模式, 即以大面积耕地和大量技术、资金投入的规模化作物生产模式, 着重于提高人均劳动生产率; 二是人多地少的欧洲、日本模式, 即以劳动、技术、资本密集投入和原材料、自然资源合理配置的集约化作物生产模式, 着重于提高单位耕地生产率[3]。根据中国当前的实际情况, 作物生产应将上述两种模式有机结合起来, 形成具有中国特色的作物生产发展新模式, 即集约规模化, 以集约化作物生产为主, 向规模化作物生产发展, 实现单位耕地生产率与人均劳动生产率同步提高的目标。
2 作物生产发展的机遇
随着作物品种的改良, 栽培管理技术的进步, 化学肥料等农资的足量供应, 中国作物生产能力已得到稳步提高, 20世纪80年代温饱问题就已基本解决, 20世纪90年代还出现了卖粮难的情况。进入21世纪以来, 中国粮食作物生产在经历一个短暂的低谷后实现了连续12年增产, 不仅粮食安全有了稳定的保障, 也为中国作物生产转型奠定了坚实的基础。在由传统作物生产向现代作物生产发展的过程中, 中国的作物生产已实现了3个转变。一是由于农村劳动力, 特别是青年劳动力向城镇的转移, 作物生产实现了由以人工劳动密集型的分散式精耕细作栽培向以省工简便栽培的适度规模化生产的转变; 二是由于农业机械、农田改造及其机械与农艺技术融合发展, 生产上实现了由以人工劳动和畜力耕地为主向以耕田机、播种机、施肥机、施药机、收割机等机械化作业为主的转变; 三是由于化学肥料的足量供应, 作物生产实现了由有机肥料施用为主向以化学肥料施用为主的转变[4]。上述转变的实现为转型期作物生产积累了宝贵的经验。其中, 值得一提的是, 由于优质有机肥料资源缺乏和有机肥施用所需劳动力成本太高, 且研究证明作物生产中化肥的合理施用并不会造成土壤板结、土壤有机质含量下降等问题[5,6], 因此转型期作物生产还将以化学肥料施用为主。但在南方的一些地方, 猪粪等畜禽粪便已成为环境污染的重要来源, 当地政府应在政策上给予适当的扶持, 积极创造条件将粪便变成简易有机肥应用, 实现变废为宝。
另一方面, 随着社会经济的发展, 中国已经实现了由以农业经济为主的“以农补工”向以工业经济为主的“以工补农”的历史性转变, 具体表现在以下方面。一是政策惠农, 包括农业免税、农业保险、粮食直补、农机补贴、粮食最低保护价收购等, 已惠及到亿万农民; 二是政府给力, 包括耕地承包权、经营权、管理权的分立, 为规模化种植大户、专业合作社等作物生产组织方式的发展提供了法律保障; 三是技术进步, 包括作物生产的机械化、信息化等, 既提升了作物生产技术, 又加速了作物生产、流通、市场一体化的进程。此外, 大量民间资本转向投资作物生产也是“以工补农”的重要体现。上述转变无疑为促进中国作物生产向规模化、集约化发展创造了新的机遇。
3 作物生产发展的挑战
中国由于人口多、人均耕地少, 实现作物高产更高产不仅是科学家追求的目标, 也是各级政府积极倡导的方向。这在温饱问题未解决, 粮食供给处于紧平衡的时期正确无疑。但随着经济的发展, 消费者对优质农产品的需求越来越大。并且, 高产更高产目标指导下的作物生产不仅投入多、比较效益低, 而且抗灾能力脆弱。与此不同, 当前农户对作物生产目标的重视程度首先是利润最大化, 其次是减少劳动力投入和规避风险, 其中专业农户更偏重利润和风险, 兼业农户更重视减少劳动力[7]。这不仅导致作物生产目标变化, 从以往的单纯追求高产到目前的质量与效益并重, 即优质高产, 而且导致作物种植方式发生根本变化, 直播、机插等轻简化、机械化种植方式迅速发展。这一作物生产技术转型不仅导致多熟制作物生育期缩短、大田种子用量增加, 还由此带来了作物杂种优势利用价值的下降, 这也正是作物生产发展急需解决的3个科学问题。3.1 多熟制作物生育期缩短
多熟制作物生育期缩短的原因主要来自两方面。一是由于作物的种植方式由传统的育苗移栽发展为直播栽培, 或者机械移栽(水稻), 直播栽培的生育期一般要比育苗移栽缩短30 d左右, 即便是机插栽培(水稻秧龄期15~20 d)也要缩短10~15 d; 二是在规模化生产条件下, 多熟制作物(稻-稻、稻-油、稻-麦、稻-稻-油等)的茬口农耗时间延长, 可导致作物的生育期进一步缩短(表1)。对于双季稻-绿肥生产, 由于双季早稻采用直播或机插栽培需要提早至3月下旬翻耕稻田, 导致冬季绿肥(紫云英)生育期缩短约30 d。Table 1
表1
表1长江中下游地区基于水稻生产的作物多熟种植条件下的作物生育期比较
Table 1
| 种植制度 Cropping system | 人工育苗移栽 Manual seedling transplanting | 人工直播栽培 Manual direct seeding | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 前茬作物 Previous crop | 后茬作物 Subsequent crop | 前茬作物 Previous crop | 后茬作物 Subsequent crop | |||||||
| 播种期 Sowing date (month/day) | 生育期 Growth duration (d) | 播种期 Sowing date (month/day) | 生育期 Growth duration (d) | 播种期 Sowing date (month/day) | 生育期 Growth duration (d) | 播种期 Sowing date (month/day) | 生育期 Growth duration (d) | |||
| 早稻-晚稻 Early season rice-late season rice | 3/20-3/30 | 110-120 | 6/15-6/25 | 110-120 | 4/5-4/10 | 100-110 | 7/10-7/15 | ≤100 | ||
| 中稻-再生稻 Middle season rice-ratoon rice | 4/1-4/5 | 130-140 | 8/10-8/15 | 60-65 | 4/5-4/10 | 125-135 | 8/10-8/15 | 60-65 | ||
| 中稻-油菜 Middle season rice-oilseed rape | 4/10-5/20 | 135-150 | 9/5-9/15 | 215-230 | 5/10-5/20 | 125-135 | 9/25-10/10 | 190-200 | ||
| 中稻-小麦 Middle season rice-wheat | 4/10-5/20 | 135-150 | — | — | 5/15-5/25 | 120-130 | 9/20-10/20 | ≤190 | ||
| 春玉米-晚稻 Spring maize-late season rice | 4/1-4/5 | 110-120 | 6/15-6/25 | 110-120 | 4/5-4/10 | 110-115 | 7/10-7/15 | ≤100 | ||
| 烟草-晚稻 Tobacco-late season rice | 12/15-12/30 | 185-200 | 6/15-6/25 | 110-120 | — | — | 7/10-7/15 | ≤100 | ||
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3.2 大田生产用种量增加
油菜、棉花等作物适应机械化收割需要大幅度增加种植密度(通常采用直播栽培), 以缩短开花期, 提高成熟整齐度。这就必然导致种子用量的大幅增加, 油菜、棉花的直播栽培是如此, 玉米直播、水稻直播及机插栽培也是如此(表2)。Table 2
表2
表2长江中下游地区不同种植方式条件下作物的种植密度和用种量比较
Table 2
| 作物 Crop | 人工育苗移栽 Manual seedling transplanting | 人工直播栽培 Manual direct seeding | |||||
|---|---|---|---|---|---|---|---|
| 种植密度 Planting density (×103 hills hm-2) | 用种量 Seed rate (kg hm-2) | 种植密度 Planting density (×103 hills hm-2) | 用种量 Seed rate (kg hm-2) | ||||
| 常规种子 Inbred seed | 杂交种子 Hybrid seed | 常规种子 Inbred seed | 杂交种子 Hybrid seed | ||||
| 油菜 Oilseed rape | 30-45 | 1.5-3.0 | ≤1.5 | ≥300 | 7.5-9.0 | ≤4.5 | |
| 棉花 Cotton | 15-45 | 15-30 | ≤15.0 | 67.5-180 | 45-60 | ≤30 | |
| 水稻 Rice | 180-360 | 45-60 | ≤22.5 | 450-750 | 60-90 | 30-45 | |
| 玉米 Maize | 45-60 | — | ≤15.0 | 120-150 | — | 30-45 | |
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3.3 作物杂种优势利用价值下降
在作物生育期缩短(早熟)的前提下, 提高或维持较高作物产量最可能的技术途径是增加种植的密度, 生产上密植最简单的方法就是直播, 密植栽培直接制约棉花、油菜、水稻等杂交作物分枝(分蘖)优势的发挥。早熟、密植栽培会带来作物杂种优势利用价值下降的问题, 并最终将影响杂交作物生产的发展。4 作物生产发展的展望
4.1 发展密植高光效栽培
作物多熟种植是保障国家粮油及食品安全的重要举措。但在作物由分散种植过渡到规模化种植, 由育苗移栽发展为直播栽培及机械移栽的转型期, 多熟制作物生育期缩短15~30 d, 密植栽培是维持较高群体干物质生产的有效方法, 即密植高光效栽培途径。作物密植高光效栽培对品种的要求主要是耐密植性、抗倒伏能力以及叶片的光合能力强等。因此, 对于作物密植高光效栽培, 主要是研究碳氮互作、光氮互作等科学理论, 研究可实现前期促进早发、中期快速积累、后期维持功能等的栽培技术。4.2 提高杂交作物种子质量
国内外大量研究证明作物杂交品种比常规品种具有显著的增产潜力[8,9,10,11], 已在作物生产特别是水稻、玉米等粮食作物增产中发挥了不可替代的作用。在作物密植栽培大幅度增加用种量的前提下, 如何继续发挥作物杂种优势利用价值, 迫切需要提高杂交作物的种子质量, 同时改进播种技术。例如, 杂交玉米由于种子的发芽率高达99%以上, 生产上可采用单粒播种技术, 大幅度减少了种子用量。最近, 笔者研究提出了杂交水稻单本密植大苗机插栽培技术, 即通过光电比色筛选种子, 包衣剂包衣种子, 定位单粒印刷播种等技术的配套应用, 实现了用种量较传统机插减少60%以上, 但前提是筛选后的杂交水稻种子发芽率及其成苗率均要求达到98%以上。需要注意的是, 对于玉米、水稻等适度密植栽培的杂交作物, 可以通过提高种子发芽率减少种子用量, 而对于棉花、油菜等高度密植栽培的杂交作物, 仅仅提高种子发芽率, 则难以达到减少直播栽培种子用量的目的, 还有待进一步开展相关研究。4.3 加强育种与栽培协同攻关
随着作物生产的转型, 作物的品种需求也正在发生新的变化。例如, 长江中下游地区的传统杂交油菜、杂交棉花生产主要采用育苗移栽方式, 且栽插密度较小, 即稀植栽培, 以塑造分枝发达的大个体植株, 发挥其分枝能力强的杂种优势。但这种由大个体组成的作物群体, 其开花期长, 成熟期差异大, 不便于机械化收割。同样, 对于杂交水稻, 育种专家偏好选育大穗型或超大穗型品种, 以充分挖掘杂交水稻分蘖大穗的高产潜力, 而栽培专家则希望培育由多穗大穗组成的高产群体, 不仅保证杂交水稻稳产高产, 同时还可节省氮肥[12,13,14,15]。由此可见, 转型期作物生产更加需要加强育种与栽培的协同攻关。又如, 随着消费者对优质农产品需求的增加, 优质作物品种越来越受到青睐, 但优质与高产往往存在一定的矛盾, 要解决这一矛盾也需要加强育种与栽培的协同攻关。作物的增产途径一是提高收获指数, 二是增加干物质产量。但目前大多研究表明, 作物产量的增加将主要依赖于生物产量的提高[16,17]。以水稻为例, 大多研究认为超级杂交稻品种高产主要是因为其干物质生产能力强, 尤其是抽穗后的干物质生产能力强[18,19]。但笔者近年研究发现超级杂交稻中也存在收获指数高的品种, 其最高收获指数可达59% [20,21]。一般来说, 由作物大个体组成的群体生物产量较高, 而由小个体组成的群体则收获指数较高。生产上是否可通过增加栽插密度提高作物的收获指数, 收获指数提高后又是否会对抗倒性产生影响等均值得进一步研究。另外, 如何实现适当扩大作物叶面积指数、增加群体干物质产量的同时提高收获指数, 协调和平衡作物个体与群体的生长发育, 需要作物育种专家和栽培专家的协同研究。
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DOI:10.1093/jxb/err248URLPMID:21963614 [本文引用: 1]
Abstract In recent years, agricultural growth in China has accelerated remarkably, but most of this growth has been driven by increased yield per unit area rather than by expansion of the cultivated area. Looking towards 2030, to meet the demand for grain and to feed a growing population on the available arable land, it is suggested that annual crop production should be increased to around 580 Mt and that yield should increase by at least 2% annually. Crop production will become more difficult with climate change, resource scarcity (e.g. land, water, energy, and nutrients) and environmental degradation (e.g. declining soil quality, increased greenhouse gas emissions, and surface water eutrophication). To pursue the fastest and most practical route to improved yield, the near-term strategy is application and extension of existing agricultural technologies. This would lead to substantial improvement in crop and soil management practices, which are currently suboptimal. Two pivotal components are required if we are to follow new trajectories. First, the disciplines of soil management and agronomy need to be given increased emphasis in research and teaching, as part of a grand food security challenge. Second, continued genetic improvement in crop varieties will be vital. However, our view is that the biggest gains from improved technology will come most immediately from combinations of improved crops and improved agronomical practices. The objectives of this paper are to summarize the historical trend of crop production in China and to examine the main constraints to the further increase of crop productivity. The paper provides a perspective on the challenge faced by science and technology in agriculture which must be met both in terms of increased crop productivity but also in increased resource use efficiency and the protection of environmental quality.
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DOI:10.3969/j.issn.1000-6850.2007.12.054URLMagsci [本文引用: 1]
为阐明长期施用化肥对土壤物理性质的影响，通过定位施肥试验研究了肥对山东棕壤、潮土和褐土3种土壤物理性质的影响。研究发现在长期定位定量施肥试验中，一年两季施用化肥不会引起土壤容重增加，造成土壤板结。结果表明单独施用化肥25年后，各施肥处理的土壤孔隙度与对照相比均有不同程度的增加，而且土壤容重均下降，不同化肥处理的土壤容重并无增大的趋势。在三大土类中，以棕壤的土壤孔隙度最低，其次是潮土，褐土最高。此外，三大土类的土壤容重均与土壤孔隙度呈显著负相关；棕壤和潮土的土壤容重与耕层有机质呈显著负相关，而褐土的土壤容重与有机质相关性较差。笔者认为长期施用化肥并未显著提高土壤容重，而能提高土壤孔隙度，因此长期单独施用化肥并非造成土壤板结的主要原因。
DOI:10.3969/j.issn.1000-6850.2007.12.054URLMagsci [本文引用: 1]
为阐明长期施用化肥对土壤物理性质的影响，通过定位施肥试验研究了肥对山东棕壤、潮土和褐土3种土壤物理性质的影响。研究发现在长期定位定量施肥试验中，一年两季施用化肥不会引起土壤容重增加，造成土壤板结。结果表明单独施用化肥25年后，各施肥处理的土壤孔隙度与对照相比均有不同程度的增加，而且土壤容重均下降，不同化肥处理的土壤容重并无增大的趋势。在三大土类中，以棕壤的土壤孔隙度最低，其次是潮土，褐土最高。此外，三大土类的土壤容重均与土壤孔隙度呈显著负相关；棕壤和潮土的土壤容重与耕层有机质呈显著负相关，而褐土的土壤容重与有机质相关性较差。笔者认为长期施用化肥并未显著提高土壤容重，而能提高土壤孔隙度，因此长期单独施用化肥并非造成土壤板结的主要原因。
DOI:10.1016/j.geoderma.2008.12.010URL [本文引用: 1]
As an essential indicator of soil quality, soil organic carbon (SOC) and its different labile fractions have an important role in determining soil chemical, physical, and biological properties. The objective of this study was to evaluate the soil carbon (C) and nitrogen (N) contents in different soil organic matter (SOM) pools (light and heavy fractions), the role of light- and heavy-fraction C in SOC sequestration, and culturable microbial counts in the surface (0鈥20聽cm) of a fluvo-aquic soil after 18聽years of fertilization treatments under a wheat鈥搈aize cropping system in the North China Plain. The experiment included seven treatments: (1) OM, organic manure; (2) 1/2OMN, half organic manure with mineral fertilizer NPK; (3) NPK, mineral fertilizer NPK; (4) NP, mineral fertilizer NP; (5) PK, mineral fertilizer PK; (6) NK, mineral fertilizer NK; and (7) CK, unfertilized control. Carbon and N contents of the light and heavy fractions were highest in the OM treatment, while the CK treatment showed the lowest value. Application of half organic manure with mineral fertilizer NPK (treatment 2) significantly increased C and N contents of the light and heavy fractions in soil in comparison with application of mineral fertilizer alone (treatments 3, 4, 5, and 6). For the mineral fertilizer treatments, a balanced application of NPK (treatment 3) showed higher C and N contents of the light and heavy fractions than an unbalanced use of fertilizers (treatments 4, 5, and 6). Heavy-fraction C dominated total SOC storage in all treatments. The total SOC increase under fertilization treatments is attributed to an increase in C content of both the light and the heavy fraction. However, the SOC increase for the manure treatments was mainly due to an increase in the C content of the heavy fraction, whereas that for mineral fertilizer treatments was mainly due to an increase in the C content of the light fraction. The total soil culturable microbial counts (including bacteria, fungi, and actinomycetes) was observed to be highest for the OM treatment, while the control plot showed the lowest value. Application of half organic manure with mineral fertilizer NPK was found to produce a higher culturable microbial counts than application of mineral fertilizers alone, and the NPK treatment gave a higher culturable microbial counts than other mineral fertilizer treatments (NP, PK or NK). Light-fraction C is probably the better predictor of microbial abundance, as it correlated more strongly with culturable microbial counts than total SOC did.
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DOI:10.1007/s10681-014-1103-7URL [本文引用: 1]
Heterosis (or hybrid vigor) is a natural phenomenon whereby hybrid offspring of genetically diverse individuals display improved physical and functional characteristics relative to their parents. Heterosis has been increasingly applied in crop production for nearly a century, with the aim of developing more vigorous, higher yielding and better performing cultivars. In this review we present and compare three categories of crop heterosis utilization: intraspecific heterosis, intersubspecific heterosis and wide-hybridization heterosis, with particular focus on polyploid species. Different pollination-control systems used to breed for heterosis are also comparatively analyzed. Finally, we highlight problems involved in heterosis research and crop improvement. We aim to provide insight into best practices for amplifying heterosis potential.
DOI:10.2135/cropsci2008.03.0154URL [本文引用: 1]
Pearl millet [Pennisetum glaucum (L.) R. Br.] single cross hybrids, bred from high-yielding parental lines in favorable environments, are not well adapted to northwest India's arid zone. The objectives of these experiments were (i) to measure grain and stover yield heterosis in testcrosses of six landrace-based restorer populations and (ii) to understand how heterosis for biomass and harvest in...
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DOI:10.1016/j.fcr.2013.04.029URL [本文引用: 1]
Plant density and nitrogen (N) input are two important factors influencing the tiller production in rice. However, it is not clear whether the negative effect of reducing planting density on tiller number per unit land area and consequently on grain yield can be offset by applying more N fertilizer. To address this question, field experiments were conducted at the Experimental Farm of Guangxi University, Guangxi Province, China in early and late rice-growing seasons in 2012. Two hybrid rice cultivars, Shenyou 9516 and Y-liangyou 087, were grown under two combinations of plant density and N rate: a locally recommended combination ( C1 ); a combination of a reduced plant density and an increased N rate ( C2 ). Y-liangyou 087 had higher tillering capacity than Shenyou 9516. Tiller number was largely lower in late season than in early season. High leaf area index and low N concentration in shoot were responsible for the low tiller number in late season. Number of maximum tillers and panicles per m 2 and grain yield were lower in early season but higher or equal in late season under C2 compared to those under C1 . The higher maximum tillers per m 2 under C2 in late season was attributed to large increase in maximum tillers per hill. Although maximum tillers per hill under C2 in early season were also increased, this increase was not sufficient to compensate for the reduced plant density. Similar to maximum tillers per hill, N uptake per hill was largely higher under C2 than under C1 in late season, while in early season the difference was relatively small. Daily temperature during the initial 20 days after transplanting was approximately 5掳C higher in late season than in early season, which was partly responsible for the larger difference in N uptake per hill between C1 and C2 in late season than in early season. Our results suggest that the decreased tiller number per unit land area and grain yield caused by reducing plant density cannot necessarily be compensated for by applying more N fertilizer.
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DOI:10.3724/SP.J.1006.2016.01176URL [本文引用: 1]
为了缓解长江中下游双季稻区机插双季稻生育期不配套的矛盾,2014—2015年早晚两季均以常规早稻品种中嘉早17为材料,在大田栽培条件下研究机插密度(36.4、28.6、19.0穴m–2)与施氮量(0、110~140、176~189 kg N hm–2)对机插双季稻产量及氮肥利用率的影响。结果表明:采用"早晚兼用"机插双季稻栽培模式有利于早、晚2季周年高产,以"高密+高氮"处理产量最高,2年分别达到16.94 t hm–2和16.99 t hm–2,但与"高密+低氮"处理的产量差异不显著;氮肥利用率随氮肥用量增加而下降,随栽插密度增加而提高,以"高密+低氮"处理最高,2年4季分别为62.77%、55.75%、65.82%、64.37%,比"高密+高氮"处理分别提高12.11%、9.01%、8.49%、2.14%;"高密+低氮"处理与"低密+高氮"处理相比,群体干物质积累量及辐射利用率均有一定的优势。由此可见,在此模式下适当增加机插密度,减少氮肥用量,既可实现高产,又能显著提高氮素利用率。采用"早晚兼用"品种搭配模式,低氮、密植栽培可作为长江中下游双季稻区机插双季稻生产的关键技术。
DOI:10.3724/SP.J.1006.2016.01176URL [本文引用: 1]
为了缓解长江中下游双季稻区机插双季稻生育期不配套的矛盾,2014—2015年早晚两季均以常规早稻品种中嘉早17为材料,在大田栽培条件下研究机插密度(36.4、28.6、19.0穴m–2)与施氮量(0、110~140、176~189 kg N hm–2)对机插双季稻产量及氮肥利用率的影响。结果表明:采用"早晚兼用"机插双季稻栽培模式有利于早、晚2季周年高产,以"高密+高氮"处理产量最高,2年分别达到16.94 t hm–2和16.99 t hm–2,但与"高密+低氮"处理的产量差异不显著;氮肥利用率随氮肥用量增加而下降,随栽插密度增加而提高,以"高密+低氮"处理最高,2年4季分别为62.77%、55.75%、65.82%、64.37%,比"高密+高氮"处理分别提高12.11%、9.01%、8.49%、2.14%;"高密+低氮"处理与"低密+高氮"处理相比,群体干物质积累量及辐射利用率均有一定的优势。由此可见,在此模式下适当增加机插密度,减少氮肥用量,既可实现高产,又能显著提高氮素利用率。采用"早晚兼用"品种搭配模式,低氮、密植栽培可作为长江中下游双季稻区机插双季稻生产的关键技术。
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Abstract Reducing external inputs, including labor and N fertilizer, is critical to sustainable double-cropped rice production in China. Dense planting is a recommended strategy to reduce N rate in rice production, and this strategy may be more practical for machine-transplanted rice as machine transplanting can achieve high hill density with less labor. However, little work has been done to demonstrate the feasibility of such a strategy in machine-transplanted double-cropped rice. This study was conducted to determine the effects of reduced N rate and increased hill density on yield attributes and grain yield in machine-transplanted double-cropped rice. Field experiments were done in two years with three treatments: (1) high N rate with low hill density (HNLD), (2) low N rate with low hill density (LNLD), and (3) low N rate with high hill density (LNHD). Results showed that LNLD had 19% and 16% less panicle number per unit land area, 27% and 26% smaller leaf area index, 18% and 14% lower biomass production, and consequently 13% and 11% lower grain yield than did HNLD in early and late season, respectively. In contrast, these yield attributes and grain yield were generally equal or higher under LNHD than under HNLD. Our study indicates that the potential negative effects of reduced N rate on yield attributes and grain yield can be compensated for by increased hill density, and suggests that dense planting is a feasible strategy to reduce N input in machine-transplanted double-cropped rice.
DOI:10.2135/cropsci1999.3961544xURL [本文引用: 1]
DOI:10.2135/cropsci1999.3961552xURL [本文引用: 1]
DOI:10.1111/jipb.2007.49.issue-6URL [本文引用: 1]
DOI:10.1016/j.fcr.2008.04.001URL [本文引用: 1]
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Description of the subject. Further increases in rice yield potential are generally thought to require greater biomass assimilation. This study presents a new cultivar that draws greater yield from increased harvest index (HI). Objectives. Our objective was to identify the physiological traits that are critical to the high yield of a recently developed short-duration rice cultivar Guiliangyou 2...
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