Characterization and implication of phytolith-associated potassium in rice straw and paddy soils

Rice straw contains up to 2.3% K in dry matter, including potassium (K) subcompartmented in phytoliths, complex siliceous structures formed in plant tissue via precipitation of Si. Rice straw is usually returned to the soil as a conventional practice to sustain soil nutrients, and therefore, the K pool accompanied with rice straw phytoliths is also cycled. Based on phytoliths obtained by ashing of rice straw at 400 °C and dissolution experiments using batch extraction in combination with physical separation of phytoliths by heavy liquid, this study evaluated the phytolith K(phytK) pool in rice straw and aged phytoliths in paddy soils. Entrapped organic matter containing K within phytolith silica cells was visualized by X-ray tomographic microscopy, and releases of this phytK pool accompanying phytolith dissolution were quantified. A 1% Na₂CO₃ solution, which has been commonly used to extract amorphous Si and to quantify soil phytoliths, showed obvious responses for K derived from phytolith dissolution, indicating that the Na₂CO₃ method can be developed for measurement of phytK. In 13 soil samples, Na₂CO₃-dissolvable K content assignable to phytK was 0.55 ± 0.39 g kg^?1 in the puddled horizon, suggesting the phytK pool is of high significance for the management of K in paddy soils.     

石灰性水稻土中磷酸铁对水稻磷营养的贡献

A study was carried out on contribution of iron phosphate to phosphorus nutrition of rice plant under waterlogged and moist conditions,respectively,by use of synthetic Fe^32 PO4.nH2O,tagging directly the iron phophate in calcareous paddy soils.Results showed that under waterlogged condition,similar to iron phosphate in acidic paddy soils.that in clacareous paddy soils was an important source of phosphorus to rice plant ,and the amount of phosphorus originated from it generally constituted 30-65% of the total phosphorus absorbed by rice plant.     

低产水稻土改良与管理研究策略

我国耕地后备资源极端缺乏,改良低产田是提高粮食产量的重要途径。低产水稻土作为低产田的重要组成部分,相关肥力特征及其改良技术研究比较零散,缺乏系统科学的调控管理策略。本文从低产水稻土类型、新的改良研究方法角度,探索可能的技术突破。基于农业部统计数据,因环境条件不良或土壤自身存在障碍因素,全国约有7.67×106hm2低产水稻土。按其主导成因,低产水稻土可分为冷潜型、粘结型、沉板型、毒质型四类。土壤质量评价是低产水稻土研究的重要方面,其评价方法主要包括土壤质量动力学法、土壤质量综合评分法、多变量指标克立格法、土壤相对质量评价法,现已发展了基于GIS的区域尺度水稻土质量评价方法,以及基于土壤生物学性状的质量评价方法。低产水稻土改良研究更多关注新技术和新方法,稳定性同位素探针技术、傅里叶变换红外光谱法(FTIR)和固相交叉极化魔角自旋13C核磁共振(CPMS13C-NMR)波谱技术的应用,将土壤有机碳的微团聚体分布、腐殖质的转化及其与土壤矿物结合机制深入到微观水平;同时高通量测序、土壤宏基因组学、宏转录组学等方法将相关研究推向分子水平。低产水稻土改良与管理的技术主要涉及到冷潜型、粘结型、沉板型、毒质型四大类低产水稻土的改良技术,基于产量反应和农学效率的推荐施肥方法是水稻土养分管理方法的重要发展方向。1)在低产水稻土质量评价方面,未来要结合不同低产类型的障碍因素开展个性化的土壤质量评价,如白土的质地和耕层厚度,加强引入土壤生物学指标进行土壤质量评价研究。2)在低产水稻土改良方面,要研究稻田障碍层次的形成机理与调控途径;研究其他低产类型如新垦水稻土、盐渍化水稻土、石灰化水稻土和污染水稻土的改良技术;研究长期改良措施对不同粒级团聚体腐殖质结构、酶类、微生物多样性和功能基因的影响。3)在低产水稻土管理方面,着重研究秸秆还田技术、推荐施肥技术、抗逆品种技术、群体控制技术。     

Micronutrient deficiencies in rainfed calcareous soils of Pakistan. III. Boron nutrition of sorghum

Abstract

Boron (B) deficiency in crops is a major micronutrient disorder particularly in alkaline‐calcareous soils. A nutrient indexing of rainfed sorghum [Sorghum bicolor (L.) Merr; cv. Potohar 4–8] in the Potohar plateau of Pakistan revealed B deficiency in 50% of the 140 sampled fields in Jehlum district and 115 fields in Chakwal district. Hot water extractable (HWE) B in the associated soils, however, indicated more widespread B deficiency. The 255 sampled fields represented 21 soil series: 100 belonging to Alfisols, 63 to Entisols, 50 to Inceptisols, and 42 to Aridisols. Boron fertility varied in various soil types; the minimum HWE B (0.25 mg/kg) was noted in Calci Ustochrepts and the maximum (0.69 mg/kg) in Fleventic Ustochrepts. Boron fertilization of an alkaline calcareous Typic Ustorthents (HWE B, 0.11 mg/kg) increased grain yield up to 32% in improved sorghum (cv. PARC‐SS‐1) and 29% in local sorghum (cv. Potohar 4–8) over the respective control yields. Fertilizer requirements for near‐maximum (95%) grain yield was 1.2 mg B/kg for the improved and 0.6 mg B/kg for local cultivar; higher fertilizer requirement of improved sorghum may be attributed to its greater biomass production. Critical plant tissue B concentration in improved sorghum was 17 mg/kg in whole shoots and 25 mg/kg in most recently matured leaves. Contrary to its lesser fertilizer requirement, internal B requirement of local sorghum was greater, i.e., 18 mg/kg in whole shoots and 31 mg/kg in leaves. The three soil tests for B, hot water, hydrochloric acid (HC1), and mannitol were almost equally effective in evaluating soil B fertility. Soil test critical B levels (mg/ kg) for improved sorghum were: hot water, 0.48; HC1, 0.43; and mannitol, 0.37. Contrary to its internal B requirements, soil test critical B levels (mg/ kg) were slightly lower for local sorghum, i.e., hot water, 0.45; HC1, 0.40; and mannitol, 0.36. Thus, local sorghum appeared more efficient in utilizing soil B. As soil test critical levels as well as fertilizer requirement were greater for improved sorghum, a much widespread B deficiency is expected in this cultivar if grown on alkaline calcareous soils of the Potohar plateau.     

Micronutrient deficiencies in rainfed calcareous soils of Pakistan. IV. Zinc nutrition of sorghum

Abstract

Zinc (Zn) deficiency in crops is a major micronutrient disorder particularly in alkaline‐calcareous soils like those of the rainfed Potohar plateau in Pakistan. A nutrient indexing of sorghum (cv. Potohar 4–8) by sampling <30 cm tall whole shoots and associated soils from 255 random field locations revealed that the crop was deficient in Zn in 54% fields in Jehlum district and 64% in Chakwal. In a greenhouse experiment using a Zn‐deficient calcareous Typic Ustorthents, maximum increase in grain yield with Zn fertilizer was 177% over control in improved sorghum variety (cv. PARC‐SS‐1) and only 10% in local sorghum (cv. Potohar 4–8). Although biomass production of cv. PARC‐SS‐1 was much greater compared with cv. Potohar 4–8, fertilizer Zn requirement for the two cultivars was not much different, 8.3 mg Zn/kg soil for improved sorghum variety and 7.3 mg Zn/kg for local sorghum variety. Contrary to its higher sensitivity to Zn deficiency, the improved sorghum variety was more efficient in utilizing fertilizer Zn. Despite low Zn availability in the Potohar fields, local sorghum is not expected to respond to fertilizer Zn. However, adequate Zn fertility must be assured for cultivating improved sorghum in these soils. Zinc content in mature grains of sorghum proved a good index of soil Zn fertility status. Internal Zn requirement in foliar plant parts of cv. PARC‐SS‐1 (whole shoots, 33 mg/kg; leaves, 22 mg/kg) was greater than in cv. Potohar 4–8 (whole shoots, 27 mg/kg; leaves, 20 mg/kg). In contrast, critical Zn content in grains of the improved sorghum variety (10 mg/kg) was lower than of local variety (14 mg/kg). Three soil tests were equally effective in determining soil Zn fertility. Critical soil Zn levels for cv. PARC‐SS‐1 were: DTPA, 3.4 mg/kg; AB‐DTPA, 3.7 mg/kg; and Mehlich 3, 8.0 mg/dm³. Similar to internal Zn requirement in foliar plant parts, soil test critical Zn levels were lower for cv. Potohar 4–8, i.e., DTPA, 3.1 mg/kg; AB‐DTPA, 3.5 mg/kg; and Mehlich 3, 7.2 mg/dm³. Because of their better efficiency, ‘universal’ soil tests appear superior to the DTPA test for routine Zn analysis.     

Characterization of cultivable methanotrophs from paddy soils and rice roots

Abstract

Characterization of methanotrophs isolated from paddy soils and rice (Oryza sativa) roots was investigated in the present study. The number of methanotrophs in root homogenates of the rice cultivar Mutsuhomare was 4.9 × 10⁷ most-probable-number (MPN) g^?1 dry roots, in Yumeakari it was 2.0 × 10⁸ MPN g^?1 dry roots and in Kirara it was 4.6 × 10⁷ MPN g^?1 dry roots. Although bacterial cells were observed infrequently on the surface and in the interiors of roots before incubation, a large number of colonies, measuring 0.5–5 mm in diameter, were observed on the sterilized roots after incubation on nitrate mineral agar plates under methane in air. In particular, a large number of colonies were observed at the emergence sites of lateral roots and root hairs. Strains MD5-1 and M1 were isolated from the roots of Mutsuhomare and strain R62 was isolated from the root homogenate of Yumeakari. All isolates were catalase-positive and oxidase-positive, Gram-negative, straight-rod-shaped and curved-rod-shaped bacteria, and formed exospores. The isolates were able to fix nitrogen and grew in the absence of copper. In addition, all were found to be positive for naphthalene-oxidizing activities (corresponding to soluble methane mono-oxygenase activities). Strains MD5-1, M1 and R62 were closely related to Methylosinus sporium. Methanotrophic strains W3-6, SD3-5 and 2-19, isolated previously from paddy field soils, were classified into Methylosinus (W3-6) and Methylocystis (SD3-5 and 2-19) type II methanotrophs. Isolates from the rice roots (MD5-1, R62 and M1) grew logarithmically when casamino acid was used as the nitrogen source; however, the growth of these strains was reduced on the nitrate medium. These strains preferred amino acids over inorganic nitrogen as a nitrogen source for growth.     

Phosphorus status of some paddy soils in Bangladesh

Abstract

Phosphorus status of Bangladesh paddy soils covering the major paddy soil types was assessed in terms of parent materials and physiography. Total P concentration ranged from 172 to 604 mg kg^?1 in the topsoil and from 126 to 688 mg kg^?1 in the subsoil, and varied with the physiography to which the soils belonged. In most soils, the available P concentration was much higher for the topsoil than for the subsoil. The inorganic P concentration was higher than the organic P concentration, except for one soil series from the Old Himalayan Piedmont Plain, and was significantly and positively correlated with the total P concentration. Among the inorganic forms, only the concentration of Al-bound P showed a significant correlation with that of available P based on the Bray P-2 method in both topsoil and subsoil. In general, the P status was critically low in paddy soils of the terrace area. Normal growth of paddy rice in this area is expected to be difficult without application of P fertilizer.     

Micronutrient deficiencies in rainfed calcareous soils of Pakistan. I. Iron chlorosis in the peanut plant

Abstract

Peanut (Arachis hypogaea L.) is susceptible to iron (Fe) chlorosis, however, plant analysis diagnostic criteria are lacking for determining the intensity of chlorosis in this crop. As total Fe content is a misleading index of Fe nutritional status of plants, determination of physiologically active Fe fraction (Fe²⁺) is suggested for the purpose. In a nutrient indexing survey of the chlorosis‐affected peanut crop grown in the rainfed Potohar plateau of Pakistan, o‐phenanthroline extractable Fe²⁺ concentration in plants decreased with increasing severity of chlorosis and thus proved an effective technique for determining the intensity of Fe chlorosis. Green plants contained 40.1 to 67.3 mg Fe²⁺/kg, mildly chlorotic 32.1 to 40.0 mg Fe²⁺/kg, moderately chlorotic 28.0 to 32.0 mg Fe²⁺/kg, and severely chlorotic <28.0 mg Fe²⁺/kg. The minimum Fe²⁺ requirement in green plants was estimated to be 40 mg/kg on dry weight basis. In rainfed field experiments on a calcareous Typic Hapludalfs soil, foliar sprays of 1% solution of sequestrene (NaFeEDDHA) proved superior to the foliar sprays of 0.5% FeSO₄.7H₂O in correcting Fe chlorosis in two cultivars of peanut. Maximum increase in pod yield with sequestrene was 42% in cv. BARD‐92 and 27% in cv. BARD‐699 over the respective control yields. Ferrous concentration in plants increased with both the Fe sources, however, a substantial increase was recorded only with sequestrene. As peanut is a low‐input high‐risk rainfed crop, correction of Fe chlorosis by using sequestrene may not be economically feasible. Thus, development and/or screening of peanut varieties tolerant to Fe chlorosis is suggested by employing Fe²⁺ analysis technique.     

钙质紫泥田水稻氮磷钾施肥效应研究

研究了钙质紫泥田水稻氮磷钾的施肥效应,分析了肥料的因素效应及合理施用量。结果表明:(1)在试验施肥量范围内,水稻产量与肥料用量呈二次多项式函数关系;(2)磷和氮的效应高,钾肥效应低;(3)棕紫泥夹砂田水稻合理施肥量为每公顷N 125~130 kg、P2O570 kg、K2O 0~30 kg,下湿紫泥田为N 85~90 kg、P2O555 kg、K2O 0~20 kg;(4)地下水位高、湿害严重,是下湿紫泥田生产水平低、施肥效果差的根本原因,改造途径是深沟排水、脱潜治理。     

复石灰水稻土的生产能力与水稻的养分吸收

在复石灰水稻土上进行的长期定位研究结果表明 ,在氮、磷充足供应、不施钾肥的条件下 ,土壤每年提供的钾素约 5 4.0kg/hm2 ,水稻产量在 60 0 0kg/hm2 左右。施用钾肥增产高达 60 %以上 ,当钾肥供应不足时 ,可用丰富的稻草部分替代 ;水稻产量与主要养分的吸收量呈极显著的正相关。氮、钾吸收量对水稻产量的影响不同 :早稻N优于K ,晚稻相反 ,K优于N。     

Co-situs application of controlled-release fertilizers to alleviate iron chlorosis of paddy rice grown in calcareous soil

Abstract

Co-situs is the placement with one application of a sufficient amount of controlled-release fertilizer for an entire growing season at any site, together with seeds or seedlings, without causing fertilizer salt injury. An experiment was conducted to find an efficient method for ameliorating Fe deficiency in two rice cultivars (cv. Tsukinohikari and cv. Sasanishiki) grown in a calcareous soil (pH 9.2, CaCO₃ 384 g kg^?1), which was poor in organic matter (0.1 g kg^?1) and available Fe (3.0 μg g^?1 soil). The field treatments consisted of co-situs application of the following fertilizers: 1) controlled-release NPK fertilizer (CRF-NPK) containing no micronutrients; 2) controlled-release NPK fertilizer containing micronutrients (CRF-M1); and 3) controlled-release NPK fertilizer containing micronutrients (CRF-M2). The main difference between CRF-M1 and CRF-M2 was that the former had larger granules than the latter. All the fertilizers were placed in contact with the roots of rice seedlings at transplanting time. Plants in the CRF-M1 and CRF-M2 treatments had similar lengths, number of stems, leaf age, and leaf color (SPAR value) during the cultivation period. By contrast, plants from the CRF-NPK treatments grew poorly, showed severe chlorosis symptoms of Fe deficiency, and all died on 30 DAT. Plants of both cultivars accumulated more macroand micronutrients with the CRF-M2 treatment than with the CRF-M1 treatment. The grain yield of cv. Tsukinohikari was 0.0, 1,910, and 2,160 kg ha^?1 for the CRF-NPK, CRF-M1, and CRF-M2 treatments, respectively, and 0.0, 2,490, and 2,860 kg ha^?1 for the same treatments for cv. Nihonbare. Chlorosis due to iron deficiency was successfully ameliorated and world-average grain yields were obtained with the co-sites application of both controlled-release fertilizers.     

硅酸盐调控抑制水稻对富硒水稻土中Cd吸收

研究目的:通过水稻盆栽试验,探讨了海泡石(SP)、硅钙复合矿物(CS)和水溶性叶面硅肥(YS)3种硅酸盐不同复配处理对富Se水稻土中Cd的迁移和转运和Se的生物有效性的调控效果,以及对糙米中矿质元素吸收的影响。结果表明,海泡石(SP)、海泡石-硅钙复合矿物(SPC)和海泡石-硅钙复合矿物-水溶硅肥(SCY)处理水稻根际土pH值增加0.15～0.31个单位,使土壤Cd由可交换态向碳酸盐结合态和有机结合态转变,而土壤Se由残渣态向生物可利用态转变。与对照(CK)相比,SP、SPC和SCY处理水稻根际土CaCl2-Cd含量降低了19.5%～34.0%,而土壤有效态Se的含量增加了17.8%～36.8%。且SPC和SCY处理糙米中的Cd含量显著降低,比食品安全国家标准(0.2mg/kg)降低了25.0%～90.0%。各处理在降低糙米中Cd的同时,对糙米中Se含量和各矿质元素(Cu、Fe、Zn、Mg和Mn)无显著影响。该研究可为进一步利用SP有效修复富Se水稻土中Cd污染和提高土壤Se的生物有效性提供了有益途径。     

不同施肥方法对双季稻区水稻产量及氮素流失的影响

为保障粮食安全,减少稻田生态系统氮肥投入,提高氮肥利用率和减少氮素流失成为重要的农业和环境措施。本研究在位于湖南岳阳的农业部岳阳农业环境科学观测实验站开展为期1年的早稻、晚稻田间试验,比较了不施肥(T_1)、尿素常规施肥(T_2,施N 280 kg·hm~(-2)、P_2O_5 165 kg·hm~(-2)、K_2O 120 kg·hm~(-2))、控释肥常规施用(T_3,施N 230 kg·hm~(-2)、P_2O_5 165 kg·hm~(-2)、K_2O 120 kg·hm~(-2))、高量控释肥侧条施用(T_4,施N 230 kg·hm~(-2)、P_2O_5 138 kg·hm~(-2)、K_2O 120 kg·hm~(-2))、中量控释肥侧条施用(T5,施N 180 kg·hm~(-2)、P_2O_5 123 kg·hm~(-2)、K_2O 120kg·hm~(-2))及低量控释肥侧条施用(T6,施N 140 kg·hm~(-2)、P_2O_5 123 kg·hm~(-2)、K_2O 120 kg·hm~(-2))下氮肥的养分利用率、作物产量及氮素流失情况,以期为稻田氮素合理利用提供理论依据。研究结果表明,控释肥侧条施用可有效提高水稻的产量和氮肥利用率,减少面源流失。1)在减少稻田秧苗数量和氮肥施用量的条件下,T_4处理的水稻早晚稻产量分别比T_2处理增加13.17%和4.72%,与T_3处理相比亦分别增加7.27%和1.74%;2)侧条施肥处理有效降低了稻田氮素流失量,年氮流失量为0.466~0.673 kg×hm~(-2),比常规施肥处理降低地表径流氮流失量3.54%~29.36%;3)侧条施肥有效提高了氮肥利用率,T_4处理的氮肥利用率分别是T_2、T_3处理的1.70倍和1.22倍。因此,采用合适的施肥方式、配施适量控释氮肥可获得较高的产值和收益。高量控释肥侧条施用(T_4)是本研究区域最佳的施肥模式,对实现现代化农业生产的高产高效、资源节约和生态环境保护具有重要意义。     

Chemical estimation of nitrogen mineralization in paddy rice soils: I. Comparison to laboratory indices

Abstract

A reliable, rapid procedure for estimating native soil nitrogen (N) mineralization potential in paddy rice (Orysa sativa L.) has eluded researchers. While several have been proposed, no technique has been sufficiently reproducible to be implemented in any soil testing program. Therefore, the objective was to develop a chemical extraction procedure as an index to estimate N mineralization in silt.loam rice soils of the Southern United States Rice Belt. Samples of silt loam soils were collected from strategic locations throughout the rice‐growing region of Arkansas during 1990 and 1991. Anaerobic incubations were performed as an index of potentially mineralisable N. Extraction with acidified potassium permanganate (KMnO₄), acidified potassium dichromate (K₂Cr₂O₇), hydrochloric acid (HCl), and oxalic acid [(COOH)₂], were evaluated at extractant:soil ratios ranging from 5:1 to 1:1. Also, distillation of centrifuged extracts (SUP) was compared to distilling the entire soil‐solution suspension (TOT). The acidified KMnO₄ and acidified K₂CnO₇ extractions gave the best overall indices of N availability. The acidifed KMnO₄ and acidified K₂Cr₂O₇ sucessfully predicted N mineralization at all ratios evaluated. A significant relationship with anaerobic incubation was observed for all HCl TOT ratios evaluated, except the 3:1 in 1991. The HCl SUP methods were not significant for all soils evaluated. The oxalic acid TOT extractable ammonium‐nitrogen (NH₄+‐N) was significantly related to anaerobic incubation. More N was extracted with the TOT methods than SUP methods, probably due to alkaline hydrolysis during distillation of TOT methods. Oxidation with KMnO₄ released the most N, while HCl and oxalic acid extracted the least.     

不同品种水稻土壤氨氧化细菌和氨氧化古菌群落结构组成

本研究通过提取土壤总DNA,利用特异引物进行PCR扩增和变性梯度凝胶电泳(DGGE),研究了不同品种水稻对稻田土壤氨氧化细菌和氨氧化古菌群落结构组成的影响.结果显示:稻田土壤具有丰富的氨氧化细菌和氨氧化古菌,且氨氧化古菌种类更多;不同品种水稻氨氧化细菌群落结构组成差异较大,其中以"天A/Km71"、"闽优1027"和"Km62/1027"3个品种相似性较高,且明显不同于其余3个品种:而氨氧化古菌群落结构组成在不同土层间表现出较大差异,其中以"天A/Km71"和"Km62/1027"的表土与根际土氨氧化古菌群落组成差异最大.研究表明不同水稻品种及土壤层次对氨氧化微生物群落结构组成具有一定影响,证明氨氧化微生物尤其是氨氧化古菌在稻田土壤生态系统中占有重要地位.     

Tillage practices improve rice yield and soil phosphorus fractions in two typical paddy soils

Journal of Soils and Sediments - This research was undertaken (I) to evaluate the status of phosphorus fractions in paddy soils in response to different tillage management practices under different...     

Influence of redox conditions and rice straw incorporation on nitrogen availability in fertilized paddy soils

Biology and Fertility of Soils - Temporal nitrogen (N) availability in fertilized rice paddies is the result of a balance of processes, mainly the gross rates of N mineralization, microbial and...     

Clay mineralogy and some chemical properties of Ap horizons of Ando soils used for paddy rice in Japan

The clay mineralogy of the Ap horizons of Ando soils in Japanese paddies was determined by a combination of methods and compared with that of Ando soils of uplands. Six of 13 paddy soil samples contained allophane and imogolite and none contained gibbsite, whereas parallel figures were 15 and 7 for 22 upland soil samples. Substantial numbers of diatoms were found in 5 paddy and 1 paddy-converted upland soil samples. The lack of gibbsite was related to the stage of soil formation rather than the paddy condition, whereas the presence of diatoms was related to both. Regarding layer silicates, there was no particular difference between the paddy and upland soil samples but one unidentified mineral with unique morphology and infrared spectrum was found in two paddy soil samples. There was no particular difference in phosphate adsorption between the paddy and upland soil samples.     

不同水稻品种混作养鸭对土壤养分动态的影响

鸭稻共作和水稻混种均可产生良好的生态效应,但能否将两项技术结合起来,即通过不同水稻品种混种与稻田养鸭的叠加,进而产生"1+12"的生态效应和生产效益,是一项值得加以实践和探讨的课题。为探明多品种水稻混作养鸭这类复合生物多样性利用模式的应用可行性,本试验设置了水稻单作常规种植(施药施肥)、水稻单作养鸭、水稻单作空白对照(不养鸭不施肥药)、水稻品种混作常规种植(施药施肥)、水稻品种混作养鸭和水稻品种混作空白对照(不养鸭不施肥药)6种种植模式开展田间试验,研究不同水稻品种混作养鸭对土壤养分动态和稻米品质的影响。结果表明:种植双季稻后,水稻品种混作养鸭处理下土壤有机质含量显著高于其他种植模式。早晚季水稻生长期间水稻品种混作养鸭处理的土壤全氮含量低于水稻品种混作常规种植处理,但均显著高于其他处理;水稻品种混作养鸭处理的土壤碱解氮含量较其他处理显著提高。各处理土壤速效磷含量以水稻单作空白对照处理的最高,总体上,混作处理比单作处理平均土壤速效磷含量高。种植双季稻后,水稻品种混作养鸭种植模式的土壤全钾和速效钾含量均高于其他处理。水稻品种混作养鸭处理的稻米出糙率、精米率、直链淀粉含量和胶稠度较其他处理高,且垩白粒率较其他处理低。综合表明,水稻品种混作养鸭模式更有利于改善田间土壤养分状况,提高稻米的品质,故此模式可为优质健康稻米生产提供新途径。