集雨种植模式下施肥和种植密度对谷子生长及水肥利用效率的影响

发布时间：2018-04-12 09:32

  本文选题：半干旱区 + 土壤水分　； 参考：《西北农林科技大学》2017年博士论文

【摘要】：水肥是限制旱区作物产量提升的两大重要因子,而合理密植是作物高产栽培的基础。农田集雨种植模式是一种适用于西北旱作农田的高效用水栽培措施,可有效提高降雨利用效率,改善旱地作物的水分状况。为完善和拓展集雨种植技术在旱区的运用,进一步挖掘其在旱地农田的水分生产潜力,本研究以半干旱区传统栽培作物-谷子为对象,从施肥量优化和群体调控两方面着手,对我国西北典型的半干旱区(宁夏彭阳县)农田集雨种植模式下谷子的高效栽培方案进行了探索。通过研究不同种植方式下(集雨种植和平作)施肥量(无肥、低肥、中肥和高肥)和密度(低密度、中密度和高密度)对农田水分养分状况、谷子生长、产量形成、水肥利用效率的影响,取得如下主要研究结果:1、不同种植模式下施肥量和密度对农田水分的影响(1)相较于平作,集雨种植方式通过垄面覆膜可有效的蓄积降雨减少农田水分的无效损失,无论在丰水年还是平水年,均可提高谷子各生育阶段0-200 cm土层的土壤水分含量。在平水年,集雨种植提高了谷子间苗期和孕穗期0-60 cm土层的土壤含水量,分别较平作提高了6.8-7.0%和6.5-30.7%,随生育进程的推进,谷子的耗水深度增加,在灌浆和收获期集雨种植改善了深层土壤水分含量。集雨种植减少了农田总蒸散量,在2013-2015年分别平均较平作减少了5.4%(27.7 mm)、11.1%(41.4 mm)和8.5%(35.1mm)。(2)增施肥料和加大种植密度均会增加谷子对土壤水分的消耗,降低耗水深度土层的土壤水分含量,年际间的表现受降雨特征和农田基础肥力的影响。在2013年,由于拔节期降雨较多,施肥量和密度处理对土壤水分的影响主要表现在灌浆期和收获期,随施肥量和种植密度的增大,谷子耗水量均呈显著增加趋势,从而导致土壤水分含量的降低;在2014年,施肥处理间的土壤水分差异主要表现在灌浆期和收获期,各施肥量水平下,土壤水分含量随种植密度的增加表现为明显降低趋势;在2015年,密度对谷子耗水的影响主要表现在营养生长阶段,施肥对谷子耗水的影响则表现在全生育阶段,孕穗和灌浆期的土壤水分随种植密度和施肥量的增大而降低,但在收获期,平作模式下土壤水分受种植密度因素的影响不明显,集雨种植下中密和高密处理间的土壤水分含量差异不明显,但均小于低密度。2、不同种植模式下施肥量和密度对谷子生长的影响(1)三年试验均表明施肥可促进谷子的生长,显著增大了谷子的株高、茎粗、单株叶面积和叶面积指数(LAI),进而提高了个体和群体的干物质积累量,当施肥超过中等施肥量(n186kg·ha-1+p2o596kg·ha-1)后,进一步增大施肥量对谷子植株生长的促进效果不明显。种植密度对谷子个体生长指标的影响大致表现为显著的负效应,但群体生长指标,如lai和群体干物质积累量均随密度的增大大致呈增加趋势,在2015年由于农田水肥条件较差,密度处理对群体干物质积累量的影响不明显。同一密度水平下,集雨种植促进谷子个体生长,株高、茎粗、单株叶面积均显著高于平作,但由于单位面积群体数量低于平作,lai、群体干物质积累量等群体指标均显著低于平作。(2)在平水年,营养器官干物质的转运量和转移率均随施肥量的增大大致呈先增加后降低的趋势,在低量或中量施肥下达到最大,过高的施肥量不利于营养器官干物质向籽粒的转运,导致转换率的降低。增大密度能够增大营养器官的群体干物质转运量,转移率和转换率的表现因施肥量不同而异。相较于平作,集雨种植显著提高了各营养器官的干物质转移率,促进了干物质向籽粒的转运,营养器官干物质的转换率在2014和2015年分别提高了14.7%和61.0%。3、不同种植模式下施肥量和密度对谷子产量形成及水分利用效率的影响(1)施肥可显著提高谷子产量和水分利用效率(wue),当施肥量超过中肥(n186kg·ha-1+p2o596kg·ha-1)后,收获指数呈下降趋势,肥料的农学利用效率和偏生产力均显著下降,两种种植模式下的谷子产量和wue在平水年的增幅不显著,而平作模式下的谷子产量和wue在丰水年增幅显著(p0.05)。施肥较不施肥显著提高谷子千粒质量,但进一步增大施肥量主要是通过提高穗粒数来实现增产的。(2)在养分充足的条件下,增大种植密度可显著提高丰水年型下谷子的产量、wue及肥料利用效率;在平水年,过高的种植密度会导致营养生长对土壤水分的过度消耗,不利于最终谷子籽粒产量的形成,导致收获指数和wue的显著下降。同一种植密度水平下,本研究集雨种植下单位面积的留苗株数较平作减少了25%,在施肥量充足的条件下,应通过适当增大种植密度来增加集雨种植下单位面积的成穗数来提高产量和wue,丰水年建议采取高密度种植(行距30cm、株距5.5cm),平水年应适当降低种植密度,以中密度(行距30cm、株距7.5cm)为宜;对平作种植而言,种植密度超过中密度后,进一步增密对产量和wue的提升效果不显著,在地力偏差的农田甚至减产。(3)在丰水年,集雨种植较平作呈减产趋势,随施肥量和密度的增大,产量及wue的减幅呈增大趋势,在高肥高密水平下,r较t的产量和wue分别降低14.3%和11.4%;在平水年,在适宜的种植密度下,集雨种植表现为增产趋势,在中量施肥和公顷留苗株数均为33.3万株的种植密度下,2014和2015年产量较平作分别提高了8.0%和6.1%。4、不同施肥量对集雨种植和平作模式下谷子养分吸收、转运及利用效率的影响(1)随施肥量的增大,谷子植株各器官的氮磷养分积累量均呈增大趋势,而氮磷素对籽粒的贡献率呈先增加后降低的趋势,在低量或中量施肥下达到最大;花前氮磷素的转移率、氮磷素的吸收效率(nupe/pupe)、收获指数(nhi/phi)和利用效率(nue/pue)均呈降低趋势。(2)在单位面积留苗株数一致的水平下(33.33万株/公顷),在平水年,集雨种植较平作提高了开花期谷子植株各器官的氮磷素积累量及氮磷素的花前转移率;在收获期,集雨种植下各营养器官的氮磷素积累量均低于平作,籽粒的氮磷素积累量显著高于平作,提高了花前氮磷素对籽粒的贡献率,但两种种植方式下的植株总氮磷素的积累量差异不显著;集雨种植下的氮磷素吸收效率、收获指数和利用效率均高于平作。在丰水年,两种种植模式间的氮磷素积累量和利用效率差异不明显。5、不同施肥量对集雨种植和平作模式下速效养分残留的影响(1)施肥可增加谷子抽穗期土壤硝态氮残留量,为生殖生长提供充足的养分环境。硝态氮淋溶深度随生育期降雨量的增多而加深,收获期硝态氮淋溶的最大积累峰均在60cm以下土层,丰水年可达120 cm,当施肥量超过中肥水平后,硝态氮的残留浓度呈明显的增加趋势;相较于平作,在中高施肥量水平下,集雨种植下土壤硝态氮的残留浓度明显增大,淋溶深度较平作增加了20 cm左右,过量施肥会相对增大集雨种植模式下土壤硝态氮的深层淋溶风险。(2)收获期土壤有效磷主要集中在0-20 cm土层,随施肥量的增加含量呈显著增加趋势,在中量施肥水平下,有效磷的含量即可达到5.0 mg kg-1以上,能够维持土壤磷素的平衡。通过施肥量优化和种植密度调控可有效提升谷子集雨种植模式下的产量及水肥利用效率,综合分析认为,在年降雨量为400 mm左右的半干旱区,谷子高产栽培的适宜施肥水平大致为中肥,即每公顷施氮186 kg、施磷96 kg,可兼顾高产与肥料的高效利用;集雨种植模式下应当通过适当增大种植沟内的种植密度来提升谷子增产潜力及水肥利用效率,大同29号品的适宜种植密度为行距30 cm、株距7.5 cm,即公顷留苗数为33.33万株。
[Abstract]:Water and fertilizer are two important limiting factor in arid crop yield improvement, which is the basis of rational close planting cultivation of crops. Farmland planting pattern is suitable for northwest dry farmland cultivation measures of high efficient water use, can effectively improve the rainfall use efficiency, improve water status of dryland crops. In order to improve and expand the planting technology in the arid areas of application, further mining in water production potential of farmland, based on the traditional cultivation crop in semi arid area of millet as the object, from two aspects of fertilizer optimization and population control on China's North West typical semi-arid region (Ningxia Pengyang county) in farmland cultivation scheme of planting pattern under the millet was explored. Through the way of study under different planting (planting peace) fertilization (no fertilizer, low fat, high in fertilizer and fertilizer) and density (low density, high in density and density) of agricultural Water and nutrient status of field millet growth, yield formation, effect of water and fertilizer use efficiency, obtained the following results: 1, the influence of fertilization and density on soil moisture under different planting patterns (1) compared with flat planting, planting way through the ridge covered with plastic can effectively reduce the loss of soil moisture accumulation rainfall is invalid no matter, or in the wet year water level, can improve the soil moisture content of millet in different growth stages of 0-200 cm soil layer. The water level, planting millet increased between seedling stage and booting stage 0-60 cm soil layer soil moisture, respectively compared with the flat was increased by 6.8-7.0% and 6.5-30.7%, along with the growth of the to promote, millet water consumption depth increased, in filling and harvest planting improved soil water content. Planting reduced evapotranspiration, in 2013-2015 years were reduced by 5.4% than the average level (27.7 mm), 11.1 % (41.4 mm) and 8.5% (35.1mm). (2) increasing fertilizer and increasing planting density increased millet consumption of soil moisture, the soil water content decreased water consumption depth, the annual performance influenced by rainfall characteristics and basic farmland fertility. In 2013, the feast of pulling more rain and the effect of fertilization and density on soil moisture mainly in the grain filling period and harvest period, with the increase of the amount of fertilizer and planting density, millet water consumption increased significantly, resulting in the reduction of soil moisture content; in 2014, soil moisture difference between fertilization mainly in the grain filling period and harvest the level of each period, fertilization, soil moisture content increased with the increase of planting density showed obvious decreasing trend; in 2015, the effect of density on water consumption of millet mainly in the vegetative stage, effects of Fertilization on water consumption of millet in the performance The whole growth stage, soil moisture at booting and filling stage decreased with the increase of planting density and fertilizer quantity, but in the harvest period, average soil moisture patterns affected by planting density factors is not obvious, planting density and differences in soil moisture content and high density treatments was not obvious, but less than the low the density of.2, the effect of fertilization and density on growth of millet under different planting patterns (1) three years test showed that fertilization could promote the growth of millet, millet significantly increased the plant height, stem diameter, leaf area and leaf area index (LAI), and then improve the individual and collective accumulation the material, when fertilization over medium fertilization (n186kg ha-1+p2o596kg HA-1), further increase of the amount of fertilizer on Millet plant growth promoting effect is not obvious. The effect of planting density on the growth index of millet individual is approximately expressed as a significant negative effect, but the group The growth index, such as dry matter accumulation increased with the density increasing and increased Lai Group in 2015 due to poor soil fertility conditions, the density effect on dry matter accumulation of groups is not obvious. The same density level, planting millet to promote individual growth, plant height, stem diameter, leaf the area was significantly higher than that of flat, but because of the number of groups per unit area is lower than that of flat, Lai, dry matter accumulation and population index were significantly lower than that of flat groups. (2) the water level, vegetative organs dry matter translocation amount and transfer rate increased with the increase of the amount of fertilizer was increased first and then decreased the trend, reached the maximum in low volume or amount of fertilization, fertilization is not conducive to high dry matter translocation to grain nutritional organs, cause the conversion rate decreased. Increasing the density of vegetative organs of groups can increase the amount of dry matter transferred, the transfer and conversion rate. The performance for fertilization varies. Compared with flat planting, planting significantly increased the vegetative organs dry matter transfer rate, promote the dry matter translocation to grain, vegetative organs dry matter conversion rate of 14.7% and 61.0%.3 were increased in 2014 and 2015, different planting mode of fertilization and density formation and water use efficiency of Millet Yield (1) fertilization can significantly increase the yield and water use efficiency of Millet (WUE), when the amount of fertilizer than in fertilizer (n186kg ha-1+p2o596kg HA-1), harvest index decreased, fertilizer agronomy utilization efficiency and partial factor productivity decreased significantly, growing two under the mode of Millet Yield and WUE was not significant in the average year increase, while flat mode Millet Yield and WUE in wet year increased significantly (P0.05). Compared with the treatments of fertilization significantly increased millet 1000 grain weight, but further increase of the amount of fertilizer Mainly by increasing the grain number per spike increase. (2) in nutrient rich conditions, the increase of planting density can significantly improve the rainy years under Millet Yield, WUE and fertilizer use efficiency; the water level, high planting density will lead to excessive consumption of vegetative growth on soil moisture, is not conducive to the formation of the final grain yield of millet, resulting in a significant decrease in harvest index and WUE. The same planting density levels in the study area, planting under the unit number of the left seedling is flat as reduced by 25% in the amount of fertilizer in adequate condition should be set to increase the area of planting unit's spike to improve the yield and WUE by increasing planting density, wet year recommended high planting density (row spacing of 30cm, 2 and 5.5cm), water level should be reduced to planting density, medium density (row spacing of 30cm, 2 and 7.5cm) is appropriate; planting on flat, planting density Over the medium density, further increasing the density on the yield and enhance the WUE effect is not remarkable, even cut in fertility of farmland. The deviation (3) in wet year, planting a flat declined with the increase of the amount of fertilizer and density, yield and WUE reduction increases in high fertility high level, R is t and WUE yield were reduced by 14.3% and 11.4%; the water level, the suitable planting density, planting showed increase trend in fertilization and the number of the left seedling were 333 thousand hectares were planting density, the yield is flat in 2014 and 2015 respectively increased by 8% and 6.1%.4, different fertilization on planting mode for peace millet nutrient absorption, transport and utilization efficiency (1) with the increase of the amount of fertilizer, nitrogen and phosphorus accumulation in different organs of Foxtail Millet plant increased, and nitrogen and phosphorus in the contribution rate to grain increased after reduce 鐨勮秼鍔，

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