耕作方式和秸秆还田对直播稻田土壤有机碳及水稻产量的影响

研究了直播稻田在不同耕作方式和秸秆还田下土壤有机碳(SOC)和水稻产量的变化。结果表明,秸秆还田能够显著增加SOC含量,耕作方式可显著影响土壤有机碳的垂直分布。SOC含量与水稻籽粒产量存在显著的正相关关系(R2=0.712 9**,n=6),SOC含量与土壤全氮(TSN)之间有显著的正相关性(R2=0.860 9**,n=43)。秸秆还田能够促进土壤有机碳的增加,稳定直播稻田系统的生产力,实现粮食安全和生态环境安全的双赢。     

土壤耕作方式对双季稻产量构成与穗镉积累的影响

为比较研究不同土壤耕作方式(翻耕、旋耕、免耕)对南方双季稻区水稻产量构成与稻穗镉积累分配特性的影响,探讨镉污染稻田双季稻最优土壤耕作方式,2015—2017年,以陵两优211与威优46为早、晚稻供试品种,在湖南省湘潭县易俗河镇中度镉污染稻田(全镉含量0.86 mg/kg)开展定位试验,比较研究了双季免耕、双季翻耕、双季旋耕、早旋晚免、早翻晚免5种土壤耕作方式下土壤有效镉含量、双季稻的产量构成与穗镉积累分配情况。结果表明:(1)双季稻产量以双季翻耕处理最高,早翻晚免处理次之,双季旋耕与早旋晚免处理再次之,双季免耕处理最低;翻耕处理产量最高的原因在于其有效穗数与每穗粒数较高。(2)齐穗期至成熟期,穗镉含量一般呈增长趋势;第1年早晚稻齐穗期穗镉含量以免耕处理最高,但免耕能明显降低水稻齐穗至成熟期穗镉含量的增长速率;早晚稻成熟期穗镉含量一般以翻耕处理较高,免耕与旋耕处理较低,免耕与旋耕处理有差异但在不同年份与季别间表现不尽相同。(3)成熟期稻穗各部位镉含量趋势表现为枝梗谷壳糙米;第1年糙米镉含量以免耕处理较高,但第2,3年呈现免耕处理低于翻耕与旋耕处理的趋势。(4)第1年早、晚稻穗镉累积量均以旋耕处理较低,但第2,3年均以免耕处理较低。(5)较其他处理而言,双季免耕明显提高了土壤有效镉含量,双季旋耕则降低了土壤有效镉含量。3年定位试验表明,土壤耕作方式对镉污染稻田土壤有效镉含量、双季稻产量构成与稻穗镉积累分配有明显影响,从保证双季稻产量、降低稻米镉含量与轻简省工的角度出发,早翻晚免是中度镉污染双季稻田的最优土壤耕作方式。     

分蘖期土壤水分对早稻矿质养分吸收的影响

在池栽条件下研究了不同水分处理对早稻吸收氮磷钾及分蘖生产效率的影响。结果表明：土壤水分对早稻吸收N、P、K矿质元素有明显影响。随着土壤水分含量的提高，植株对矿质元素的吸收量显著提高。在分蘖初期，65％水分处理的植株对N、P、K的吸收量分别只有100％的74．1％，43．9％和50．8％，而在分蘖后期，则分别只有100％的41．4％，18．6％和27．5％。早稻矿质元素的分蘖生产效率以在85％土壤含水量时最高，其N、P、K的平均分蘖生产效率分别比100％高35．7％，140％和81．8％。平均分蘖生产效率表现为P〉K〉N。     

分蘖期土壤水分对旱稻矿质养分吸收的影响

在池栽条件下研究了不同水分处理对旱稻吸收氮磷钾及分蘖生产效率的影响。结果表明:土壤水分对旱稻吸收N、P、K矿质元素有明显影响。随着土壤水分含量的提高,植株对矿质元素的吸收量显著提高。在分蘖初期,65%水分处理的植株对N、P、K的吸收量分别只有100%的74.1%,43.9%和50.8%,而在分蘖后期,则分别只有100%的41.4%,18.6%和27.5%。旱稻矿质元素的分蘖生产效率以在85%土壤含水量时最高,其N、P、K的平均分蘖生产效率分别比100%高35.7%,140%和81.8%。平均分蘖生产效率表现为P>K>N。     

成都平原免耕及不同麦秸还田量种植水稻的研究

在成都平原麦收后围绕免耕 麦秸覆盖还田栽种水稻的产量效应进行了研究,结果表明,(1)免耕处理较传统耕作水稻显著增产,主要是显著增加了单位面积有效穗数;(2)免耕 麦秸覆盖还田后,水稻产量增加,秸秆还田量与产量的关系符合多项式y=7238.6 0.0117x 2.12×10-5x2-1.49×10-9x3(R=0.988**),理论上还田麦秸以10 089 kg/hm2时水稻产量最高,此后开始下降;(3)与传统耕作比较,在水稻生长期,免耕明显加重了杂草的发生,但通过秸秆覆盖后可减少杂草发生,且表现出随秸秆还田量增加杂草量明显减少的趋势;在水稻收获后的休闲期,免耕表现出有抑制杂草发生的作用,且这种效果随着秸秆还田的增加而增强。     

Effect of Planting Method on Grain Quality and Nutrient Utilization for No-Tillage Rice

Field experiments were conducted over 2 years using six rice (Oryza Sativa L.) cultivars to investigate the effect of two planting methods, transplanting (TP) and direct sowing (DS), on grain quality and nutrient utilization. Brown and head rice percentages, grain width, amylase, and protein content were greater in TP than in DS, whereas the opposite effect was found for chalkiness rate, gel consistency, and alkali spread value (ASV). Dramatic differences were also found between the two planting methods for nutrient harvest index and utilization efficiency, with TP having greater phosphorus (P) and potassium (K) harvest indexes, nitrogen (N) and K utilization efficiencies, and lower N harvest index and P utilization efficiency than DS. Moreover, significant differences between these genotypes could be found for both nutrient harvest index and utilization efficiency. The correlation analysis showed that rice chalkiness, transparency, gel consistency, amylose, and protein contents were all significantly correlated with N, P, and K nutrient traits. In addition, significant interactions between rice cultivar and planting methods for both rice quality and nutrient traits were also found.     

水旱轮作条件下长期自然免耕对土壤理化性质的影响

通过实地调查，采集不同免耕年限土壤进行对比分析，研究了水早轮作条件下长期自然免耕对土壤理化性质的影响。结果表明：水早轮作条件下，不进行秸秆覆盖长期双免耕的农耕措施对土壤理化性质有较大的影响。0～15cm土层容重随免耕年限的增加而减小，免耕7～8年后趋于稳定，而15～30cm土层的容重几乎不受影响；土壤团聚度随免耕年限的增加而增加，表层增加更明显；土壤有机质、全氮、速效氮和磷含量均随免耕年限增加而逐年上升，并且有明显表聚现象，但对速效钾的影响则不明显。     

Phosphorus Nutrition of Lowland Rice in Tropical Lowland Soil

Rice is a main food crop for about half of the world's population, and phosphorus (P) is the main limiting nutrient in rice production in tropical lowlands. A greenhouse experiment was conducted to evaluate P requirements of lowland rice grown on a lowland soil (Inceptisol). Dry matter, grain yield, and yield-attributing characteristics were significantly (P < 0.01) influenced by P fertilization. Based on quadratic response, maximum shoot dry weight and grain yield were obtained with the application of 190 mg P kg^?1 of soil. Maximum panicle, tiller number, and plant height were obtained with the application of 177 192, and 175 mg P kg^?1 of soil, respectively. Mehlich 1–extractable P for maximum grain yield was 15.6 mg kg^?1 of soil. Variability in grain yield with plant growth and yield parameters was in the order of tiller > shoot dry weight > panicle number > spikelet sterility > plant height > grain harvest index > panicle length > weight of 1000 grains. Phosphorus uptake in shoot and concentration and uptake in grain significantly (P < 0.01) increased grain yield. However, variability in grain yield was greater with concentration and uptake of P in the grain. Similarly, P harvest index was also significantly associated with grain yield. Agronomic P-use efficiency, apparent P-recovery efficiency, and P-utilization efficiency decreased quadratically with increasing P rates, whereas physiological P-use efficiency increased quadratically and agrophysiological P-use efficiency decreased linearly with increasing P rates. Agrophysiological and utilization P-use efficiencies had significant positive correlation with grain yield.     

孕穗期施硅对高温下扬花灌浆期水稻干物质转运及产量的影响

为探明硅对高温逆境下水稻产量形成的调控效应,以圣稻19为试验材料,通过大田增温试验研究了孕穗期叶面施硅对高温下扬花灌浆期水稻干物质转运与产量的影响。结果表明,与不施硅相比,施硅显著提高了高温逆境下水稻叶片干物质输出量、输出率、转化率,对茎鞘干物质的输出转化无显著影响;减弱了自然温度下水稻叶片干物质的转化率。高温或自然温度下,施硅均显著提高了水稻库容量;高温逆境下,施硅显著增加了水稻结实率与产量,但显著降低了千粒重;自然温度下,显著提高了水稻结实率、千粒重与产量。施硅后叶片输出转化效率与结实率的增加是弥补高温下水稻产量损失的主要因素。本研究结果为完善水稻耐热栽培调控技术提供了有益参考。     

Plant Nitrogen Accumulation Dynamics in Rice in Response to Nitrogen Management

This study investigates the effect of rice nitrogen (N) management on the dynamics of plant nitrogen accumulation (PNA) during internodal elongation (IE) in relation to grain yield. Four field experiments were conducted in two soils with six preflood N treatments. The PNA was monitored for 3 weeks, starting at the beginning of IE (BIE). The PNA explained 54–72% of yield variability. The effect of midseason N application on yield varied with fields, indicating a need for assessing midseason N requirement for each field. One week after BIE was a better time to assess the N requirement of rice crop. The greatest grain yields in Cocodrie and Wells cultivars corresponded to PNA of 10.9 and 11.1 g m^?2 at BIE. A midseason application of 50 kg N ha^?1 as urea at 7–10 days after BIE increased the rice yield in the Glossaqualfs field when the PNA at BIE was less than 8.3 g m^?2.     

穗肥施用时期对优质稻产量、氮素积累及品质的影响

为了探明优质晚籼稻(Oryza sativa L. subsp. xian)产量和品质协同提升的适宜的穗肥施用时期,采用大田微区¹⁵N示踪技术,以优质晚籼稻Y两优911和野香优莉丝为材料,设置3个穗肥施用时期(D₁：倒4叶期施肥;D₂：倒3叶期施肥;D₃：倒2叶期施肥),研究穗肥施用时期对优质稻产量、籽粒氮素积累及食味品质的影响。结果表明,随着穗肥施用时期的推迟,两个优质晚籼稻品种的产量先升高后降低,在D₂达到最高产量,较D₁、D₃显著增产4.30%～6.39%;籽粒总氮积累量、¹⁵N标记肥料氮素积累量及其占比、¹⁵N标记肥料氮素回收利用率、¹⁵N标记肥料氮素收获指数表现为增加趋势,D₂和D₃较D₁显著增加19.16%～21.26%、32.54%～50.75%、0.91～2.49、12.42～23.34和...     

Effect of Soil Moisture Content and Phosphorus Application on Phosphorus Nutrition of Rice Cultivated in Different Water Regime Systems

Abstract

Pot experiments were conducted in a glasshouse to investigate the effect of soil water content and phosphorus (P) supply on biomass, P uptake by rice cultivated in soils with different water regimes and soil available P. Results showed that P application rates had greater effect on P nutrition of rice than soil moisture content. Yield of rice grain was significantly decreased when soil moisture content was kept at 60% of water holding capacity (WHC) while the yields of rice grain were not significantly different when soil moistures were remained at 80% of WHC and waterlogged. This meant that it was possible for paddy rice variety to be cultivated in aerobic soil under the condition of sufficient P supply. The highest biomass of rice and highest P uptake by rice were found in the treatment with 0.0300 g P kg^?1 of P application rate and with 80% of WHC. Soil available P content decreased with the decrease of both the soil moisture content and the P applied. Rice crop exhausted soil P to a great extent leading to very low available soil P content when the rice crop was harvested, especially in the soil receiving no or small amounts of P fertilizer. All the results obtained in this experiment could provide the theoretic base for water and P management of paddy rice variety cultivated in aerobic soil in the southern hilly areas of China.     

非包膜缓释复合肥对水稻氮素营养的效应研究

采用盆栽试验研究了非包膜缓释复合肥（SRCF）、包膜缓释复合肥（Multicote）和普通复合肥（CCF）对水稻植株生长和氮素营养的影响。结果表明,盆栽试验施用SRCF的水稻茎叶重、根冠比、含氮量、对肥料氮的吸收量和利用率与Multicote处理的相应指标较为相近,明显优于普通无机复合肥,这表明SRCF的氮素养分具有缓慢释放性能,并能满足水稻不同生长期的氮素需要。     

非包膜缓释复合肥对水稻氮素营养的效应研究

采用盆栽试验研究了非包膜缓释复合肥(SRCF)、包膜缓释复合肥(Multicote)和普通复合肥(CCF)对水稻植株生长和氮素营养的影响。结果表明,盆栽试验施用SRCF的水稻茎叶重、根冠比、含氮量、对肥料氮的吸收量和利用率与Multicote处理的相应指标较为相近,明显优于普通无机复合肥,这表明SRCF的氮素养分具有缓慢释放性能,并能满足水稻不同生长期的氮素需要。     

土壤pH值与镉含量对水稻产量和不同器官镉累积的影响

为探明水稻产量与镉积累分配对土壤pH值和镉含量的响应,以3个籽粒Cd含量差异明显的晚稻品种(天优华占,TY;星2号,X2;湘晚籼13号,XW)为试验材料,分别于不同pH值稻田研究土壤镉(Cd)含量对水稻产量和不同器官Cd累积的影响,并比较了品种间差异。结果表明,水稻产量因土壤pH值下降而下降,且品种间降幅差异明显,以X2最大(21.72%33.81%),XW最小(3.05%17.71%);添加0.5 mg·kg^-1Cd时水稻减产不显著,但添加1.0 mg·kg^-1Cd时各品种均显著减产,且其降幅与品种和土壤pH值有关,X2和XW在酸化条件下降幅较大,而TY在正常pH条件下降幅较大。植株(整株)Cd含量存在品种间差异,各品种植株Cd含量均随着土壤Cd浓度的提高与土壤pH值的下降而显著提高,且植株Cd含量峰值因土壤酸化而提前。水稻器官间Cd含量依次表现根>茎>穗>叶,各器官Cd含量均随着土壤Cd浓度提高而显著增大,但增大倍数存在器官间差异;品种间器官Cd含量差异明显,营养器官表现为X2>TY>XW,而稻穗表现为TY>X2>XW。水稻各器官及全株Cd累积量均随着土壤Cd浓度提高和土壤pH值降低而显著增大,成熟期累积量表现为茎>穗>根>叶;品种间Cd累积量差异明显,营养器官和整株Cd累积量表现为X2>XW>TY,而穗Cd累积量表现为TY>X2>XW。Cd分配比例一般以茎为最高,叶最低,土壤酸化使茎、叶所占比例增大,根、穗所占比例降低;品种间Cd分配比例存在一定差异,穗Cd所占比例表现为TY>X2>XW。可见,水稻产量与器官间Cd累积分配规律受到土壤Cd含量和pH值的影响显著,同时也具有明显的品种间差异。本研究为不同水稻品种在不同pH值与Cd含量稻田上的应用提供了理论依据。     

保护性耕作对黄壤坡耕地水土流失及作物产量的影响

[目的]分析保护性耕作对黄壤坡耕地水土流失及作物产量的影响,为贵州省坡耕地水土流失治理及农业可持续发展提供科学依据。[方法]在西南地区典型黄壤坡耕地设置不施肥+顺坡平作(TR_1)、常规施肥+顺坡平作(TR_2)、优化施肥+顺坡平作(TR_3)、优化施肥+横坡垄作(TR_4)、优化施肥+横坡垄作+秸秆覆盖(TR_5)、优化施肥+横坡垄作+秸秆覆盖+等高植物篱(TR_6)共6个不同试验处理的监测小区,于2017—2018年监测了不同处理间作物产量、地表径流量、氮磷流失量、土壤养分含量的差异,并分析其相关性。[结果]①TR_4,TR_5,TR_6较TR_3的径流量分别减少了59.72%,74.13%和89.18%,氮磷流失总量与径流量趋势相同;②TR_5,TR_6对全量养分含量影响最大,其中全氮比TR_4作高20.00%,23.67%,比TR_3高23.53%,27.31%;③TR_4,TR_5,TR_6处理下的玉米在保持较高产量的同时,作物产量稳定性(SI)和可持续性(SYI)最好;④玉米、油菜产量与全氮、全磷、有效磷、有机质呈极显著正相关(p0.01),与速效氮呈显著正相关(p0.05);玉米产量与氮素流失量、磷素流失量、径流量呈极显著负相关(p0.01)。[结论]在坡耕地实施保护性耕作能有效降低地表径流发生,减少氮磷流失,保持土壤养分肥力的同时促进作物高产,并实现稳产及可持续生产,且实施综合保护性耕作的效能大于单项保护性耕作。     

菜籽饼堆肥对水稻土壤Cd有效性及Cd在水稻全生育期转运与累积的影响

为研究菜籽饼堆肥对土壤Cd有效性和在水稻体内迁移转运与累积的影响,在Cd污染(Cd=0.72 mg/kg)土壤中施用不同添加量(0.75%,1.5%,3.0%)的菜籽饼堆肥,以未添加菜籽饼堆肥为对照(CK),并进行水稻盆栽种植试验。结果表明:(1)菜籽饼堆肥进入稻田土壤后会显著降低土壤中TCLP提取态Cd含量,在熟化期施用0.75%～3.0%的菜籽饼堆肥,与对照相比土壤TCLP提取态Cd含量下降了45.1%～68.7%。但水稻的种植会影响菜籽饼堆肥对土壤中TCLP提取态Cd含量的降低效果,使其含量随着水稻生育期的延长逐渐上升,但仍低于同时期的对照土壤。(2)施用菜籽饼堆肥能显著提高水稻产量,但同时也增加水稻糙米中Cd含量。与对照相比,施用0.75%～3.0%的菜籽饼堆肥,水稻糙米中Cd含量为0.04～0.14 mg/kg,低于国家食品中污染物限量标准(GB 2762—2012, Cd<0.2 mg/kg)。同时,每株水稻产量分别增加3.6～4.3 g/株,约为1 620～1 935 kg/hm^2。(3)施用菜籽饼堆肥会提高Cd在水稻体内的转运能力,同时显著提高水稻成熟期各部位Cd累积量,特别是地上部分。总体来说,施用菜籽饼堆肥增加水稻糙米中Cd含量,但依然保持在较低水平,满足中轻度Cd污染地区水稻的安全生产。但在Cd污染程度更高或者土壤Cd活性更强的土壤中施用菜籽饼堆肥,种植水稻糙米Cd含量可能高于国家食品中污染物限量标准。因此,在保证稻米安全的前提下对Cd污染稻田应该谨慎施用菜籽饼堆肥。     

锌离子活度对水稻锌积累与分配的影响

采用HEDTA螯合剂缓冲营养液培养法,选用籽粒含锌量有明显差异的2个基因型水稻(BY和Z921),设置4种锌离子活度(pZn2+9.7、10.3、11.0、11.4),研究了锌离子活度对水稻锌积累、分配的影响以及对不同时期水稻叶片中锌的化学形态的影响。结果显示:(1)2个基因型水稻各器官的锌含量都随着锌离子活度的升高而升高,但不同基因型间,同一基因型不同器官间均存在差异,供锌正常的的条件下,锌首先向代谢活性较弱的营养器官分配;缺锌的条件下,锌首先满足籽粒的需要;(2)从籽粒锌分配看,当锌离子活度(pZn2+)小于10.3时,糙米锌含量最高,当pZn2+升高到9.7时,颖壳锌含量则超过糙米,糙米和精米锌含量的比值在0.79～0.90之间,并以pZn2+为9.7时为最小;(3)任一锌离子活度下,BY籽粒锌含量均大于Z921。表明通过筛选籽粒富锌水稻品种来提高稻米锌含量是经济可行的,且通过增加环境锌离子活度来改善水稻的锌营养能显著提高水稻籽粒的锌含量;(4)营养生长前期,水稻叶片中的锌主要以活性较低的醋酸提取态(重金属磷酸盐)存在;营养生长后期,锌主要以乙醇提取态(醇溶性蛋白、氨基酸等)存在。     

缓释复合肥与覆膜旱作对水稻氮素营养的效应研究

采用田间试验和化学分析方法．研究了3种缓释复合肥对覆膜早作水稻生长、产量、叶片氮素形态、氮肥利用率和稻米品质的影响。结果表明．施用高氮型无机型缓释复合肥（SRF1）条件下，覆膜早作（DF）水稻植株生长、产量、氮素营养和稻米品质优于常规淹水栽培（CF），DF和CF的氮肥表观利用率分别为64．90％和37．15％。同为覆膜早作时．施用高氮型有机无机缓释复合肥（SRF1）的水稻农艺性状、产量及分蘖期和孕穗期植株叶片氨基酸、NO2^- -N含量较高，而植株叶片蛋白氮和全氮含量以高氮型无机缓释复合肥处理（SRF1）较高，氮肥表观利用率和农业利用率均以SRF2〉SRF1〉SRF3，氮肥生理利用率差异不大。覆膜早作和施用缓释复合肥能提高稻米营养品质，稻米氨基酸和蛋白质含量与水稻分蘖期叶片的蛋白氮和全氮含量皆呈显著正相关。     

Screening of Basmati Rice Varieties for their Arsenic Accumulation in Punjab,North-West India

A pot study was conducted to screen different basmati rice varieties for their accumulation of arsenic (As). Different amounts of arsenic (0–800 µg/L) were applied through irrigation water to four basmati rice varieties (Pusa basmati-1121, Pusa Punjab basmati-1509, Punjab basmati-2, and Punjab basmati-3). Highest arsenic concentration was found in the grains of Punjab basmati-3 and lowest in the grains of Pusa Punjab basmati-1509. In all varieties, grain As concentration ranged from 0.038 to 0.288 mg/kg, which was within the permissible limit of 1.0 mg/kg in rice grain recommended by World Health Organization (WHO). In husk, highest As concentration was found in Pusa basmati-1121 and lowest in Punjab basmati-2. Among the four varieties, highest content of As was accumulated in roots and straw of Pusa Punjab basmati-1509, whereas least was accumulated in Punjab basmati-2. The distribution of arsenic among plant parts was found in the order: roots > straw > husk > grain. The mean arsenic concentrations in grain, husk, straw, and root of basmati rice varieties increased with increasing concentration of arsenic in irrigation water. Highest grain yield was obtained in Pusa Punjab basmati-1509 variety due to lesser accumulation of arsenic compared with other varieties. Rice yield, plant height, root weight, straw weight, test weight, effective tiller, and filled grain per panicle decreased with increase in arsenic concentration in irrigated water.