Effect of Application of Acidified Porous Hydrate Calcium Silicate and Porous Hydrated Calcium Silicate on the Growth of Rice Plants (Oryza sativa L.)

The effect of the application of acidified porous hydrate calcium silicate (APS) in nursery bed soil and porous hydrate calcium silicate (PS) in paddy fields on the growth of rice plants ( Oryza sativa L. cv. Hitomebore) was examined in 2002 and 2003. The results revealed the following: 1) Shoot dry weight of rice seedlings increased by APS treatment in nursery bed soil. The tiller number of rice plants after transplanting in both years also increased by APS treatment in nursery bed soil, and in 2003, the tiller number in the treatment with a combination of APS in nursery bed soil and PS in paddy fields was significantly higher than that in the other treatments until the maximum tiller number stage. Furthermore, the root length of rice plants 14 d after transplanting increased by APS treatment in nursery bed soil. 2) Silicon concentration in the soil solution significantly increased by PS treatment in paddy fields, and the concentration of dissolved carbon oxide increased by APS treatment in nursery bed soil. 3) Only in the APS treatment the rice yield was 341 g m⁻², while 400 and 450 g m⁻² in the PS and both APS and PS treatments, respectively, in 2003. Percentages of ripened grains in the plots without PS treatment ranged from 57 to 63%, respectively, while, those in the PS treated plots were 82%. The numbers of panicles and ripened grains in both APS and PS treatments were the highest among the treatments. Based on the above results, we concluded that both APS in nursery bed soil and PS in paddy field treatments were effective in improving the silicon nutrition and growth of rice plants, and that this effect was enhanced by a combination of treatments with the two.     

Effectiveness of arbuscular mycorrhizal colonization at nursery-stage on growth and nutrition in wetland rice (Oryza sativa L.) after transplanting under different soil fertility and water regimes

In order to analyze the effectiveness of colonization by arbuscular mycorrhizal fungi (AMF) at the nursery stage on the growth and nutrient concentration of wetland rice after transplanting, the experiments were conducted under glasshouse conditions using two types of soil, namely (i) sterilized paddy soil (PS) and (ii) sterilized paddy soil diluted with sterilized Andosol subsoil 5 times (DS) under two water regimes, (i) flooded conditions changed to non-flooded conditions 30 d before harvest (F-NF) and (ii) continuous flooding (CF) up to harvest. Treatments consisting of mycorrhizal inoculation (+AMF) and non-inoculation ( — AMF) were applied only at the nursery stage when the seedlings were produced under dry nursery (60% moisture of maximum water holding capacity) conditions.

Seedlings grown in PS showed a significantly higher biomass yield and nutrient concentrations than in DS. At 90 and 105 d after transplanting, the mycorrhizal plants showed a higher biomass than non-mycorrhizal plants in PS whereas there were no differences in DS except for roots. Mycorrhizal colonization at the transplanting stage was higher in DS than in PS. However, after transplanting opposite results were obtained, the level in PS being relatively higher than in DS. Grain yield and P concentration of unhulled grain and shoots in PS were higher in the +AMF treatments than in the -AMF treatments under both water regimes. Contents of micronutrients (Zn, Cu, Fe, and Mn) were higher in the +AMF plants than in the -AMF ones at all growth stages up to maturation irrespective of soil fertility and water regimes. These results suggest that AMF inoculation at the nursery-stage was beneficial for wetland rice after transplanting to flooded conditions in terms of growth promotion and increase of nutrient concentrations.     

Chemical and morphological changes of porous hydrated calcium silicate in paddy soil

The chemical and morphological changes of porous hydrated calcium silicate material (PS) during the dissolution process in paddy soil were investigated by using both a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) analysis. The results showed that original PS consisted of agglomerate of various sizes with almost the same elemental composition. The SEM images at a high magnification showed that the original PS consisted of agglomerates of small platelike crystals (≦ μm) of tobermorite [Ca₅(Si₆O₁₈-H₂)·4H₂O]. On the other hand, elemental composition showed that the PS agglomerates in paddy soil altered to Si- and Ca-rich agglomerates after incubation for 53 d. The morphological differences between the two types of agglomerates were observed by SEM at a high magnification. The Si-rich agglomerates were similar to the original PS in morphology, whereas the Ca-rich agglomerate appeared as a large crystal. The X-ray diffraction patterns obtained in a previous study suggested the presence of quartz and calcite in PS after incubation for 53 d (Saigusa et al. 2000: Soil Sci. Plant Nutr., 46, 89–95). Si- and Ca-rich agglomerates were identified as silica skeletons of PS and calcite, respectively. It was suggested that the silica skeletons of PS remained as a silicon source for rice plants even after the disappearance of tobermorite revealed by the X-ray diffractogram.     

Amelioration of Cadmium Polluted Paddy Soils by Porous Hydrated Calcium Silicate

Porous hydrated calcium silicate (PS) is a by-product of autoclave light weight concrete and is being used as a silicon fertilizer in Japan. The impacts of this amendment on the yield and cadmium content of rice (Orzya sativa L. var. Kokoromachi), soil pH and the extractability of soil cadmium assessed by 1 M NH₄OAc were compared with those of silica gel and CaCO₃ by pot experiments. The application of PS at the rate of 2.0% and silica gel at the rate of 1.0% in Andosol and PS at the rate of 0.75% in Alluvial soil significantly increased the grain weight of rice. PS and CaCO₃ treatment significantly increased soil pH, decreased the 1 M NH₄OAc extractability of cadmium and reduced cadmium content in straw and brown rice in the two soils. However, cadmium content of rice of PS treatments was not significantly different from that of CaCO₃ treatments in Andosol, while was significantly lower than that of CaCO₃ treatments in Alluvial soil. Soil analysis showed that it was less effective in increasing soil pH and decreasing the extractability of cadmium by 1 M NH₄OAc than CaCO₃ at the same application rate in Andosol. Soil pH and 1 M NH₄OAc extractability of cadmium were not significantly different between 2.0% of PS and CaCO₃ treatments in Alluvial soil. The application of silica gel did not improve soil pH nor decrease the extractability of soil cadmium, but resulted in a significant decline of cadmium content in brown rice. These results demonstrate that the supply of silicon together with an increase in soil pH, as obtained by PS application, shows potential to reduce the cadmium content of rice.     

Effects of slag silicate fertilizer on silicon content of rice plants grown in paddy fields on the Shounai Plain,Yamagata, Japan

Abstract

Slag silicate fertilizer (SSF) is applied to paddy fields with different soil chemical properties to increase silicon (Si) concentration in rice (Oryza sativa L.) plants. However, the effects of soil chemical properties on Si availability of SSF to rice Si uptake is poorly understood. To investigate the relationships between chemical properties of soils and the effects of SSF application on the Si concentration in rice plants, a field experiment was conducted in 2007 and 2008 at 18 paddy fields on the Shounai Plain, Yamagata, Japan. Two treatments were implemented: SSF applied at 1.5 t ha^?1 and a no-SSF control. The Si concentrations of rice tissues were measured at the tillering and ripening stages. The difference in the Si concentrations of rice tissues between treatments (ΔSi concentration) was used to evaluate the effect of SSF. The Si concentrations in the shoots and aboveground parts of the rice plants were significantly increased by the SSF application in six or more of the fields at the two growth stages, whereas the Si concentrations in the panicles of the rice plants at the ripening stage were not increased significantly in most fields. Results of two-way analysis of variance evidenced a significant effect of field on the ΔSi concentrations in the shoots and aboveground parts at both growth stages. Furthermore, the ΔSi concentrations in the same rice plant tissues and at the same growth stages in the first year and in the second year were found to be positively correlated. These results indicate that the effect of SSF on the Si concentration in shoots and aboveground parts of rice plants varies from field to field. The ΔSi concentrations in shoots and aboveground plant parts at both growth stages were also found to be negatively correlated with soil chemical properties, i.e., available Si, Si adsorption capacity, contents of Si adsorbents (acid oxalate-extractable iron and manganese) and the pH under flooded soil conditions. These findings imply that those soil chemical properties of paddy fields should be taken into account for better prediction of ΔSi concentration of rice plants.     

Integrated rice management simultaneously improves rice yield and nitrogen use efficiency in various paddy fields

The hilly area of Southwest China is a typical rice production area which is limited by seasonal droughts and low temperature in the early rice growth period. A field experiment was conducted on three typical paddy fields (low-lying paddy field, medium-elevation paddy field, and upland paddy field) in this region. Nitrogen (N) treatment (180 kg N ha^-1 year^-1) was compared to a control treatment (0 kg N ha^-1 year^-1) to evaluate the effects of integrated rice management (IRM) on rice growth, grain yield, and N utilization. Integrated rice management integrated raised beds containing plastic mulch, furrow irrigation, and triangular transplanting. In comparison to traditional rice management (TRM), IRM promoted rice tiller development, with 7-13 more tillers per cluster at the maximum tillering stage and 1-6 more tillers per cluster at the end of tillering stage. Integrated rice management significantly increased the rice aboveground biomass by 34.4%-109.0% in different growth periods and the aboveground N uptake by 25.3%-159.0%. Number of productive tillers significantly increased by 33.0%, resulting in a 33.0% increase in grain yield and 8.0% improvement of N use efficiency (NUE). Grain yields were significantly increased in all three paddy fields assessed, with IRM being the most important factor for grain yield and productive tiller development. Effects of paddy field type and N level on N uptake by aboveground plants were reflected in the rice reproductive growth period, with the effects of IRM more striking due to the dry climate conditions. In conclusion, IRM simultaneously improved rice yield and NUE, presenting a valuable rice management technique in the paddy fields assessed.     

不同育秧基质和水分管理对机插稻秧苗素质与产量的影响

为探明适宜机插秧苗的培育方式,本文以杂交中灿稻‘徽两优6号’为材料,研究了营养土旱育、营养土湿润育秧和淤泥水育秧等3种方式对机插水稻秧苗素质及产量的影响,并分析了不同育秧方式对秧龄弹性、机插活棵及分蘖成穗的效应。结果表明:播后21 d,营养土旱育秧苗综合素质最好,营养土湿润育秧次之,淤泥水育秧的最差;与淤泥水育秧相比,营养土旱育秧及湿润育秧的秧苗发根力强,根冠比高,干物质积累能力强。其中旱育秧适栽秧龄为18~30 d,秧龄弹性最大。营养土旱育方式育秧能在稳定结实率和千粒重的情况下显著提高有效穗数和群体颖花量,增加库容量,从而使产量显著增加。旱育秧栽后缓苗期短、活棵快、发根力强、分蘖起步早,能较好破除本田生育前、中、后期的生长不平衡,有利于优良群体构建和高产形成。     

有机无机肥配施对潜育化水稻土的改良效应

为探索潜育化水稻土改良培肥措施,采用田间试验研究了工程排水条件下有机无机肥配施对潜育化低产水稻土的改良效应。结果显示:有机无机肥配施增加了早、晚稻的有效分蘖数。在早稻齐穗期,与CK和NPK处理相比,有机无机肥配施的叶绿素(SPAD值)均显著增加。有机无机肥配施显著增加了晚稻的产量,与NPK处理相比,产量增加了10.0%~23.7%;其中早稻配施紫云英、晚稻配施猪粪处理产量最高。在工程排水基础上,配施有机肥处理在早、晚稻收获时耕层土壤还原物质总量分别比单施化肥处理减少了15.0%~25.3%和32.5%~37.5%。这表明,在工程排水条件下,配施一定的有机肥可以明显提高潜育化稻田水稻产量,降低表层土壤还原物质总量,对改良潜育化水稻土有明显作用。     

Nitrogen use efficiency,water saving and yield of rice transplanting on raised bed over traditional flat method

Flat transplanting with flooded irrigation is commonly used for growing rice, but it results in ineffective use of applied fertilizer and water. The objective of this study was to compare nitrogen use efficiency and water saving of rice transplanted on beds and on flat ground. This field experiment was performed in randomized complete design for three continuous years and all treatments were repeated three times. Results showed that transplanting of four lines of rice nursery on bed and one line in furrow and nitrogen application at 150 kg ha^?1 recorded 16.06, 21.81, 16.0 and 20.21% higher paddy yield, nitrogen (N) uptake in paddy, N use efficiency and N agronomic efficiency than traditional flat method at same N level. Without loss in yield, about 25 kg ha ^?1 of N fertilizer and 24% of water can be saved with bed transplanting of rice as compared to flat method.     

Coal Fly Ash and Phospho‐gypsum Mixture as an Amendment to Improve Rice Paddy Soil Fertility

Abstract

Rice is a plant that requires high levels of silica (Si). As a silicate (SiO₂) source to rice, coal fly ash (hereafter, fly ash), which has an alkaline pH and high available silicate and boron (B) contents, was mixed with phosphor‐gypsum (hereafter, gypsum, 50%, wt wt^?1), a by‐product from the production of phosphate fertilizer, to improve the fly ash limitation. Field experiments were carried out to evaluate the effect of the mixture on soil properties and rice (Oryza sativa) productivity in silt loam (SiL) and loamy sand (LS) soils to which 0 (FG 0), 20 (FG 20), 40 (FG 40), and 60 (FG 60) Mg ha^?1 were added. The mixture increased the amount of available silicate and exchangeable calcium (Ca) contents in the soils and the uptake of silicate by rice plant. The mixture did not result in accumulation of heavy metals in soil and an excessive uptake of heavy metals by the rice grain. The available boron content in soil increased with the mixture application levels up to 1.42 mg kg^?1 following the application of 60 Mg ha^?1 but did not show toxicity. The mixture increased significantly rice yield and showed the highest yields following the addition of 30–40 Mg ha^?1 in two soils. It is concluded that the fly ash and gypsum mixture could be a good source of inorganic soil amendments to restore the soil nutrient balance in rice paddy soil.     

施用尿素、红萍对水稻生长及其氮素利用效率的影响

应用~(15)N示踪技术研究了尿素和红萍氮素对水稻分蘖、成穗和产量的影响以及当季水稻对氮素的利用率。结果表明:30十30kgN/ha尿素分别作基肥和分蘖期追肥(U-2),10十20十30kgN/ha尿素分别作基肥、分蘖肥和穗肥(U-3),30十30kgN/ha的红萍分别作基肥和分蘖期追肥(A-2),和不施氮肥对照(CK)处理,水稻分蘖总数分别为465.0,495.0,579.0,403.5万/ha;成穗率分别为81.9％,78.8％,69.8％,74.4％;每穗平均粒数分别为75.8,80.6,78.2,74.7粒。施红萍的稻谷产量与等氮量尿素相当。施用尿素和红萍处理,水稻生长前期平均出蘖速度明显不同,而且水稻不同时期分蘖,其成穗数和每穗粒数均随分蘖时间推移呈逐渐递减变化。试验结果表明:红萍作基肥当季的氮素利用率为41.3—48.2％,高于尿素作基肥的利用率(28.0—31.9％),但尿素作追肥(45.7—46.2％)则优于红萍作追肥(37.5—43.2％)。U-3,A-2,U-2处理当季氮素利用率分别为47.7—50.6％,39.2—45.7％,37.0—38.8％。     

不同类型钙化合物对污染土壤水稻吸收累积Cd Pb的影响及机理

以潮泥田和红黄泥为供试土壤,利用盆栽试验研究了施用不同类型钙化合物（CaO、CaCO3、CaSO4）对水稻吸收累积Cd、Pb的影响及机理。结果表明,潮泥田施用CaO和CaCO3后,土壤pH值明显升高。当CaO施用量达到0.36gCa·kg-1时土壤有效态Cd含量显著降低,水稻糙米Cd含量也随之显著下降,降幅达26.3%;施用CaCO（30.24gCa·kg-1）和CaSO（40.24gCa·kg-1）后水稻糙米Cd含量降幅分别为23.7%（P〈0.05）和18.4%（P〈0.05）。红黄泥施用CaO、CaCO3和CaSO4后,土壤pH值变化趋势与潮泥田相同。当CaO施用量达到0.24gCa·kg-1时土壤有效态Cd含量显著降低,但水稻糙米Cd含量反而上升,当CaO施用量达到0.36gCa·kg-1时,与对照相比水稻糙米Cd含量增加34.5%（P〈0.05）;当CaO施用量增至0.48gCa·kg-1时土壤有效态Pb含量明显增加,水稻糙米Pb含量也随之显著增加,增幅达41.7%。在等钙（0.24gCa·kg-1）条件下,潮泥田及红黄泥施用CaO、CaCO3和CaSO4后因pH变幅较小导致水稻糙米Cd、Pb含量无明显差异。综合分析认为,利用钙化合物控制污染土壤上水稻对cd、Pb的吸收累积时,需要根据土壤Cd、Pb含量和pH综合考虑合理的钙化合物类型和用量。     

掺混型缓/控释肥对杂交晚稻产量的影响

采用田间小区试验,以不施肥(CK1)和施用等量NPK化肥(CK2)为对照,研究掺混型缓/控释肥对水稻产量的影响.结果表明,各缓释肥处理的产量均高于等量NPK处理.其中,在长沙点中肥力水稻土上,35%聚乙烯醇混聚物(CF2)胶结复混肥+65%废弃泡沫塑料(PS)混聚物包膜复混肥(简称CF2+PS)效果最好,比等量NPK处理增产27.68%,其次是35%高岭土-聚酯胶结肥+65%PS包膜肥,比等量NPK处理增产24.70%;在宁乡点低肥力水稻土上,35%高岭土-聚酯胶结肥+65%PS包膜肥处理效果最好,比等量NPK处理增产37.25%;宁乡试验点各施肥处理的增产效果均高于长沙点,说明土壤肥力越低,肥料的增产率越高;减少20%掺混型缓释复混肥施用量(处理9),仍然比等量NPK处理增产,说明根据作物各生育期对养分的需求比例,将不同时间段释放养分的缓释肥料按比例掺混,效果较佳,节肥、增产是可行的.     

秸秆覆盖旱作对稻田甲烷排放和水稻产量的影响

为较全面评价秸秆覆盖旱作水稻栽培模式的生态意义,采用田间试验研究了常规淹水（F）、秸秆覆盖旱作（NF-M）和无覆盖旱作（NF-ZM）3种栽培模式稻田甲烷排放、水稻产量及土壤养分的变化规律。结果表明：3种水稻栽培模式的甲烷排放均集中在水稻生育期的前20d;在水稻生育期内,秸秆覆盖旱作稻田甲烷的排放总量为11.12g·m^-2,显著高于常规淹水稻田的7.78g·m^-2和无覆盖旱作稻田的4.23g·m^-2。秸秆覆盖旱作稻田的水稻产量为8.60t·hm^-2,与常规淹水处理没有显著差异,但二者均显著高于无秸秆覆盖旱作处理的6.78t·hm^-2;与常规淹水处理相比,秸秆覆盖旱作还可以提高水稻单株生物量10g以上。秸秆覆盖旱作还可以显著提高稻田表层土壤有机质含量,维持和改善表层土壤养分状况,对实现农业可持续性有重要意义。因此,在水资源缺乏地区,秸秆覆盖旱作是一种值得考虑的替代传统淹水栽培的水稻栽培模式,同时秸秆覆盖旱作还田也是一种值得推广的稻田秸秆管理技术。     

过氧化钙及硅钙肥改良潜育化稻田土壤的效果研究

【目的】潜育化水稻土是我国最主要的低产水稻土类型,长期渍水导致的土壤缺氧及活性还原物质过度积累是其最主要特征,这严重影响了水稻的根系发育和产量提高。本研究以鄱阳湖区潜育化稻田土壤为对象,通过田间试验研究过氧化钙和硅钙肥单施或配施对潜育化稻田土壤的改良效果,旨在为探索潜育化稻田的轻简化改良方法提供理论依据。【方法】田间试验于2012 2013年在鄱阳湖区潜育化双季稻田进行,试验设单施化肥(T1)、化肥+硅钙肥(T2)、化肥+过氧化钙(T3)和化肥+硅钙肥+过氧化钙(T4)4个处理。通过2年4季的田间试验研究了过氧化钙和硅钙肥单施或配施对鄱阳湖区潜育化稻田水稻产量、土壤还原物质总量及土壤物理化学性质的影响,分析了过氧化钙和硅钙肥改良潜育化稻田土壤的效果和应用前景。【结果】过氧化钙和硅钙肥单施或配施均可以提高潜育化稻田的水稻产量,二者配施每季可以提高水稻产量1.06 t/hm22.06 t/hm2,并可促进磷、钾养分向籽粒转移。施硅钙肥对土壤还原物质总量没有明显影响,而施过氧化钙可以显著降低土壤还原物质总量,二者配施可以减少耕层土壤还原物质总量1 cmol/kg以上。随着土层的加深,土壤还原物质总量呈增加的趋势。硅钙肥与过氧化钙配施可以明显提高小于10 mm的中小团聚体的含量。施硅钙肥或过氧化钙对土壤养分含量没有明显影响,但二者配施可以明显提高土壤有机碳、速效磷的含量,但对腐殖质碳、速效钾和全氮含量影响不明显。【结论】施用硅钙肥可以提高潜育化稻田的水稻产量,但对土壤还原物质总量没有明显影响。施用过氧化钙既可以提高水稻产量,又可以降低潜育化稻田的潜育化程度。而硅钙肥和过氧化钙配施不仅可以明显提高水稻产量、降低潜育化稻田的潜育化程度,还可以改善土壤养分供应状况和土壤结构。因此,施用过氧化钙和硅钙肥可以作为改良鄱阳湖区潜育化稻田土壤的一种参考方法。     

乳芽直播种植技术条件下水稻生长特性的研究

为了探索水稻直播的最佳种植工艺及其相应的机械化生产，采用田间试验方法，在辽阳市景尔屯村的20 hm²水田进行了乳芽直播、常规插秧和抛秧3个处理的水稻种植对比试验。对培育期乳芽的根长、根数和高度等生长特征的研究结果表明，练苗环节对根长和乳芽高度的增长速度有明显的抑制作用，但对乳芽根数的增加无影响。对秧苗生长中期的性状特征研究结果表明，与其它2个处理相比，乳芽直播的秧苗在5月20～7月27日期间生长较快，分蘖和抽穗开始时间早，分蘖节位低，但由于播种密度太大，有效分蘖率较低。对3个处理的产量形成指标检测结果表明，乳芽直播处理的穗数密度为538.7万穗/hm²，每穗结实粒数为76.8粒，千粒重为0.0246 kg。     

长江中下游平原单季稻田氮素径流损失风险评估

稻田氮素径流损失是农业面源污染主要来源之一,以巢湖地区单季稻田为研究对象,利用该地区1957—2019年的历史气象数据,通过设定插秧区间(6月6—25日)及施肥期水位(3,10,20 cm),建立SMNRL模型,模拟不同插秧时间和田面水水位稻田氮素流失,研究降低长江中下游平原气候区单季稻田氮素径流损失风险的插秧时间与水位控制模式。结果表明:(1)施肥后,稻田田面水氮素浓度呈指数衰减,基肥期田面水氮素衰减期为9天,分蘖肥和穗肥期为7天。(2)在LW、HW组合中,各施肥期占全生育的氮素径流损失为基肥期>分蘖肥期>穗肥期。在LW组合中,基肥期为氮素径流损失高发期,基肥、分蘖肥、穗肥的氮素流失为72.4%~98.4%,1.9%~27.6%,0~8.3%。(3)控制水位比选择插秧时间对降低氮素径流损失更有效。相同水位下,适宜的插秧期氮素径流损失在全生育期施肥中合计能减少0.4~4.5 kg/hm^2,降低32.8%~80.3%;相同插秧时间下,LW、MW组合相比HW组合氮素径流损失能减少8.8~13.1 kg/hm^2,降低92.1%~98.8%。(4)在LW、MW、HW 3种组合中,插秧期分别以6月19日、6月11日、6月17日为界,将6月6—25日分为前后2个阶段,前1阶段插秧产生氮素径流损失均值显著低于后1阶段,分别低37.0%,25.0%,21.7%。(5)降低巢湖地区稻田氮素径流损失有效措施为施肥期水位控制为3 cm,并选择6月6-19日期间进行水稻插秧。     

耕作模式对冷浸田水稻产量和土壤特性的影响

为探明不同耕作模式对冷浸田的影响机制,挖掘冷浸田的生产潜力,以冷浸田为研究对象,通过田间试验,以常规平作模式为对照,研究了垄作和稻鱼共作模式对冷浸田水稻产量以及土壤团聚体、温度、pH及有机质和还原性物质含量以及酶活性的影响。结果表明:相比对照(CK),垄作模式(T1)能显著降低土壤微团聚体(0.25 mm)含量,促进大团聚体的形成,提高土壤温度,增加土壤有机质含量,提高土壤pH,抑制水稻分蘖期后土壤亚铁含量的上升,降低土壤亚锰含量,减轻其对水稻根系的毒害作用,提高土壤酶活性,增加土壤速效养分含量。稻鱼共作模式(T2)对冷浸田土壤理化性状影响不显著,但能显著增加土壤速效养分含量,土壤速效钾含量在水稻孕穗期和成熟期分别较对照(CK)增加18.2%和69.2%,从而为水稻生长提供良好的土壤环境和营养,促进水稻生长发育,提高水稻产量。研究表明T1和T2模式能显著提高冷浸田水稻产量,增产范围为8.8%~25.8%,T1模式增产效果最显著,实际产量达到7 623 kg·hm-2。综上所述,垄作模式可以有效地改善冷浸田土壤特性,提高水稻产量,而稻鱼共作模式增产效果主要体现在增加冷浸田水体和土壤的速效养分。     

稻田长期垄作免耕对水稻产量及土壤肥力的影响研究

不同耕作条件下的水稻生长发育、作物产量及土壤肥力状况的研究表明,稻田长期垄作免耕,水稻根系数量、白根率、根系活力比常规平作和水旱轮作高,分蘖时间早;垄作免耕水稻的株高、茎粗、穗长、穗粒数增加,11年水稻平均产量垄作免耕比常规平作和水旱轮作分别提高了10.3%和11.3%。垄作免耕改变了土壤的物理、化学性状,土壤容重、土壤养分含量明显提高,土壤微生物数量和酶活性增强,土壤表层松结态腐殖质含量比常规平作和水旱轮作高0.194和0.238个百分点,紧结态腐殖质降低0.098和0.037个百分点。垄作免耕有利于提高作物产量、培肥地力、改善土壤生态环境。     

Response of Sugarcane to Calcium Silicate on Yield,Gas Exchange Characteristics,Leaf Nutrient Concentrations,and Soil Properties in Two Different Soils

Silicon (Si), applied as calcium silicate (Ca-silicate), was evaluated for effects on yield; yield-contributing parameters in sugarcane, such as chlorophyll content, gas exchange characteristics, moisture content, and leaf nutrient concentrations; and soil fertility in the greenhouse in two different soil types. Seven levels of Si (0 20, 40, 60, 80, 120, and 150 g pot^–1) were tested by applying them with traditional fertilizers. Gas exchange characteristics such as photosynthesis, transpiration, and stomatal conductance were significantly greater with the plants fertilized with silicate over unamended control for both soils. Silicate fertilization increased chlorophyll and moisture contents in the top visible dewlap (TVD) leaf tissues, but results were not significantly better in both soils when compared with unamended control. In our 12-month study, we found that the Si content reached up to 2.64% and 1.86% per dry mass in TVD leaf tissues when amended with Ca-silicate fertilizer in soils 1 and 2, respectively. Results showed that as compared to unamended control, Si-amended treatments significantly increased maximum dry matter and cane yield by 77% and 66% in soil 1 and 41% and 15% in soil 2, respectively. With increasing silicate application, iron, copper, zinc, and manganese contents significantly decreased in leaf tissues and soil contents in both soils. Soil pH, Si contents, available sulfur, exchangeable Ca and magnesium, and cation exchange capacity were increased significantly more or less, whereas aluminum contents of soil decreased dramatically in both soils when amended with Ca-silicate. Our results indicate that different soil fertility status and rates of Si application are important factors influencing the yield, growth parameters, chlorophyll, and nutrient contents of sugarcane leaf as well as soil properties.