Soil Quality Assessment of Acid Sulfate Paddy Soils with Different Productivities in Guangdong Province,China

Land conversion is considered an effective measure to ensure national food security in China, but little information is available on the quality of low productivity soils, in particular those in acid sulfate soil regions. In our study, acid sulfate paddy soils were divided into soils with high, medium and low levels based on local rice productivity, and 60 soil samples were collected for analysis. Twenty soil variables including physical, chemical and biochemical properties were determined. Those variables that were significantly different between the high, medium and low productivity soils were selected for principal component analysis, and microbial biomass carbon (MBC), total nitrogen (TN), available silicon (ASi), pH and available zinc (AZn) were retained in the minimum data set (MDS). After scoring the MDS variables, they were integrated to calculate a soil quality index (SQI), and the high, medium and low productivity paddy soils received mean SQI scores of 0.95, 0.83 and 0.60, respectively. Low productivity paddy soils showed worse soil quality, and a large discrepancy was observed between the low and high productivity paddy soils. Lower MBC, TN, ASi, pH and available K (AK) were considered as the primary limiting factors. Additionally, all the soil samples collected were rich in available P and AZn, but deficient in AK and ASi. The results suggest that soil AK and ASi deficiencies were the main limiting factors for all the studied acid sulfate paddy soil regions. The application of K and Si on a national basis and other sustainable management approaches are suggested to improve rice productivity, especially for low productivity paddy soils. Our results indicated that there is a large potential for increasing productivity and producing more cereals in acid sulfate paddy soil regions.     

Effects of Long-Term Organic Amendments on Soil Organic Carbon in a Paddy Field A Case Study on Red Soil

Soil organic carbon （SOC） is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expansion in south China. A study was carried out to evaluate the relationship between the SOC content and organic carbon input under various organic amendments at a long-term fertilization experiment that was established on a red soil under a double rice cropping system in 1981. The treatments included non-fertilization （CK）, nitrogen-phosphorus-potassium fertilization in early rice only （NPK）, green manure （Astragalus sinicus L.） in early rice only （OM1）, high rate of green manure in early rice only （OM2）, combined green manure in early rice and farmyard manure in late rice （OM3）, combined green manure in early rice, farmyard manure in late rice and rice straw mulching in winter （OM4）, combined green manure in early rice and rice straw mulching in winter （OMS）. Our data showed that the SOC content was the highest under OM3 and OM4, followed by OM1, OM2 and OM5, then NPK fertilization, and the lowest under non-fertilization. However, our analyses in SOC stock indicated a significant difference between OM3 （33.9 t ha^-1） and OM4 （31.8 t ha^-1）, but no difference between NPK fertilization （27 t ha^-1） and nonfertilization （28.1 t ha^-1）. There was a significant linear increase in SOC over time for all treatments, and the slop of linear equation was greater in organic manure treatments （0.276-0.344 g kg-1 yr^-1） than in chemical fertilizer （0.216 g kg^-1 yr^-1） and no fertilizer （0.127 g kg^-1 yr^-1）.     

湖南双季稻种植区不同生产力水稻土质量综合评价

【目的】利用非线性评价模型量化不同生产力水稻土的质量变化,为双季稻种植区水稻土的可持续利用提供科学依据。【方法】以湖南省双季稻主产区为试验样区,采用综合评价方法,将土壤质量划分为抗物理退化、养分供应与贮藏、抗生物化学退化和保持作物生产力这4项土壤功能。运用专家小组打分和因子分析相结合的方法,确定各项功能和指标的权重,用非线性评分模型对不同生产力水稻土测定的各项指标进行无量纲(0和1之间)评分。【结果】结果表明,8个试验区高产水稻土具有良好的物理、化学和生物化学质量;中产水稻土的物理质量比较好,但生物化学质量较差;低产水稻土的物理、化学和生物化学质量均较差,主要体现在有机质含量低,养分供应、贮藏能力差。【结论】高产水稻土的总体土壤质量高,对双季稻生长不构成障碍;影响中产水稻土质量的主要因子是养分供应不平衡,采用良好的管理措施可以使其土壤质量在短期内得以提高;低产水稻土的总体质量差,在这类水稻土上需要增加有机肥和无机养分的投入,改善其总体土壤质量。     

双季稻区6种不同稻田土壤类型对晚稻产量及稻米品质的影响

研究双季稻区6种不同土壤类型对晚稻产量及稻米品质的影响,可为指导不同地域的水稻优质生产提供重要参考。本文以6年定位试验为基础,研究了南方双季稻区6种不同土壤类型晚稻产量及稻米品质的变化。结果表明,在6种不同土壤类型中,各处理优质晚稻的有效穗、每穗总粒数、结实率、千粒重和产量均无明显差异。垩白大小与穗干重之间呈显著的正相关。水稻产量以红黄泥田最高,达7570.46 kg/hm2,大小顺序为红黄泥田>河沙泥>灰泥田>麻沙泥>紫泥田>黄泥田。红黄泥田和紫泥田有利于提高优质晚稻的出糙率、精米率;灰泥田和河沙泥田有利于提高稻米的整精米率;黄泥田有利于提高稻米的胶稠度、蛋白质,降低垩白米率、垩白大小和直链淀粉含量。上述结果说明,黄泥田种植水稻有利于改善稻米品质。     

应用耕作指数评价耕作措施对双季稻田土壤质量的影响

 【目的】采用耕作指数（TI）定量评价了耕作措施对双季稻田土壤质量的影响,旨在为选择合理的土壤耕作措施提供依据。【方法】试验始于2005年,在湖南省宁乡县设免耕（NT）、旋耕（RT）和翻耕（CT）3个处理,测定了2007、2008年水稻收获期0—20 cm土层有机质（SOM）、土壤容重（BD）、全氮（TN）及pH等理化性状指标,利用目的线性回归模型计算TI。【结果】有机质含量和土壤容重对双季稻田土壤质量影响显著,水稻产量与土壤有机质含量显著正相关（R2=0.45）,与土壤容重显著负相关（R2=0.67）;可通过测定有机质含量和土壤容重计算得到TI,TI = 0.40 SOM' + 0.60 BD',且与水稻产量呈显著正相关（R2=0.67）,可作为选择耕作措施的依据。试验中3个耕作处理土壤质量均有不同程度的改善,TI变化表明试验期间NT处理初期土壤质量较差（TI=0.79）,但其TI增加最快,免耕能有效地改善土壤质量。【结论】利用目的线性回归模型计算TI能够较准确的定量描述不同耕作措施下双季稻田土壤质量。免耕有利于土壤质量的改善。     

吉林省西部地区苏打盐渍化草原不同利用方式对土壤肥力质量的影响

不同利用方式对土壤肥力质量有着重要的影响.选取吉林省西部地区盐渍化草原5种不同利用方式:放牧草原、围栏草原、旱田、新开水田、老水田,分析测定了土壤的主要养分,并利用土壤质量指数法(QI)和土壤退化指数法(DI)定量研究方法分析了这5种土壤肥力质量和土壤肥力退化指数.结果表明:放牧草原QI值为22.56%、围栏草原66.56%、旱田11.90%、新水田77.11%、老水田82.34%;以放牧草原为基准其退化指数显示:旱田为负值,其他利用方式均为正值,水田和围栏草原值较高.结果均揭示水田和围栏草原土壤肥力质量较高,而放牧草原和旱田土壤肥力质量较低,呈退化趋势.     

灌溉水质对污灌区土壤重金属含量的影响分析

利用统计学方法和空间分析,对鞍山宋三灌区稻田土壤重金属含量进行了分析研究。结果表明,利用工业废水进行灌溉的稻田,土壤环境质量明显低于利用河水和城市生活污水进行灌溉的区域,土壤重金属Cd和Hg分别超标1.8倍和2.2倍。空间分析结果显示,污灌区土壤重金属含量的空间差异明显,6种重金属污染物空间分布的峰值均出现在工业废水进行灌溉的区域。由此所得结论是:工业废水中的污染物质对农田土壤环境影响明显,应避免直接用于农田灌溉;在农田土壤环境保护工作中,在对重点污染物进行分析的同时,应加强对重点区域的监测。     

Effects of Elemental Sulphur and Farmyard Manure on pH and Salinity of Calcareous Sandy Loam Soil and Some Nutrient Elements in Tomato Plant

The objective of this study was to evaluate the effects of elemental sulphur （S） and farmyard manure on soil pH, EC and N, S, P concentrations of tomato grown in a calcareous sandy loam soil. For this purpose, a pot experiment was conducted in greenhouse conditions. Sulphur was applied at 0, 50, 100, 150, 200, 400 mg kg~ and farmyard manure at 0, 3 ton da^-1 to the soil. Three weeks after applications, tomato seedlings were planted and 8 weeks later, the plants were harvested to determine N, S, P concentrations and dry matter yield. Soil pH and EC were determined in the soil samples taken at 3 different periods. Effects of sulphur and farmyard manure applications were not significant on N, P concentrations and dry matter yield of tomato plant. S concentration of tomato plant was increased by sulphur alone. Soil pH was decreased and soil EC was increased in both 2^nd and 3^rd soil sampling period by the sulphur applications. As a result of farmyard manure application, soil pH decreased in the 2^nd soil sampling period but increased in the 3^rd soil sampling period. Also, soil EC was significantly increased in 1^st and 3^rd soil sampling period. Farmyard manure had no significant effect on S supply to tomato plant. The N：S ratio of tomato plant was decreased by sulphur alone. However, the sulphur with farmyard manure applications decreased N：S ratio in lesser extend compared to the S applications.     

Crop Yield and Soil Properties in the First 3 Years After Biochar Application to a Calcareous Soil

It remains unclear whether biochar applications to calcareous soils can improve soil fertility and crop yield. A long-term field experiment was established in 2009 so as to determine the effect of biochar on crop yield and soil properties in a calcareous soil. Five treatments were： 1） straw incorporation; 2） straw incorporation with inorganic fertilizer; 3）, 4） and 5） straw incorporation with inorganic fertilizer, and biochar at 30, 60, and 90 t ha-l, respectively. The annual yield of either winter wheat or summer maize was not increased significantly following biochar application, whereas the cumulative yield over the first 4 growing seasons was significantly increased. Soil pH, measured in situ, was increased by a maximum of 0.35 units after 2 yr following biochar application. After 3 yr, soil bulk density significantly decreased while soil water holding capacity increased with adding biochar of 90 t ha^-1. Alkaline hydrolysable N decreased but exchangeable K increased due to biochar addition. Olsen-P did not change compared to the treatment without biochar. The results suggested that biochar could be used in calcareous soils without yield loss or significant impacts on nutrient availability.     

Characterization of Some Typical Soils of the Miombo Woodland Ecosystem of Kitonga Forest Reserve,Iringa, Tanzania： Physico-Chemical Properties and Classification

Despite the fact that miombo woodland soils have significant implications in global climate change processes, few studies have been done to characterize and classify the soils of the miombo woodland ecosystem of Tanzania. The current study was carried out to map and classify soils of Kitonga Forest Reserve, which is a typical miombo woodland ecosystem, in order to generate relevant information for their use and management. A representative study area of 52 km2 was selected and mapped at a scale of 1：50,000 on the basis of relief. Ten representative soil profiles were excavated and described using standard methods. Soil samples were taken from genetic soil horizons and analyzed in the laboratory for physico-chemical characteristics using standard methods. Using field and laboratory analytical data, the soils were classified according to the FAO-World Reference Base （FAO-WRB） for Soil Resources system as Cambisols, Leptosols and Fluvisols. In the USDA-NRCS Soil Taxonomy system the soils were classified as Inceptisols and Entisols. Topographical features played an important role in soil formation. The different soil types differed in physico-chemical properties, hence exhibit differences in their potentials, constraints and need specific management strategies. Texture varied from sandy to different loams; pH from 5.1 to 5.9; organic carbon from 0.9 g/kg to 20 g/kg; and CEC from 3 cmol/（＋）kg to 24 cmol/（＋）kg. Sustainable management of miombo woodlands ecosystem soils requires reduced deforestation and reduced land degradation.     

不同施肥措施对黄泥田土壤养分及水稻产量的影响

为农业有机废弃物的合理科学利用提供参考,在湖北省孝昌县单季稻区利用田间试验研究6种施肥措施对黄泥田土壤肥力及水稻产量的影响。结果表明:不同施肥措施对黄泥田土壤有效磷与速效钾含量的影响显著,对有机质、全氮及碱解氮含量的影响不明显。在6种施肥措施中,以化肥+畜禽粪肥配施黄泥田土壤的有机质、全氮、碱解氮、有效磷和速效钾含量最高,分别为23.06 g/kg、1.34 g/kg、111.66mg/kg、30.77mg/kg和148.33mg/kg,且有效磷和速效钾含量显著高于其他施肥措施(P0.05);稻谷和稻草产量也最高,分别为9 638.38kg/hm~2和11 118.39kg/hm~2,也显著高于其他施肥措施(P0.05);水稻的综合农艺性状好。因此,在黄泥田水稻生产过程中,采用化肥和畜禽粪肥配施可有效培肥其土壤,提高水稻产量。     

Soil Monitoring System as a Basic Tool for Protection of Soils and Sustainable Land Use in Slovakia

The purpose of soil monitoring system in Slovakia is better to protect the soils with regard to sustainable land use. The main objective is the observation of soil properties concerning the main threats to soil： soil contamination, salinisation and sodification, decline in soil organic matter （SOM）, soil compaction and erosion. Soil monitoring system in Slovakia is consistently running since 1993. Its importance consists of providing the information on changing spatial and temporal variations of soil parameters as well as the evolution of soil quality in topsoil and subsoil. Soil monitoring network in Slovakia is constructed using ecological principles, taking into account all main soil types and subtypes, SOM, climatic regions, emission regions, polluted and non-polluted regions as well as various land use. The results of soil monitoring of 318 sites on agricultural land in Slovakia have been presented. Soil properties are evaluated according to the main threats to soil relating to European Commission recommendation for European soil monitoring performance as follows： soil contamination, soil salinization and sodification, decline in SOM, soil compaction and erosion. The most significant change has been determined in physical properties of soils. The physical degradation was especially manifested in compacted and the eroded soils. About 50% of agricultural land is potentially affected by soil erosion in Slovakia. In addition, decline in SOM and available nutrients indicate the serious facts on evaluation and extension of soil degradation processes during the last period in Slovakia. Obtained measured data and required outputs are reported to Joint Research Centre （JRC） in lspra （Italy） and European Environmental Agency （EEA） in Copenhagen （Denmark）. Finally, soil monitoring system thus becomes a basic tool for protection of soils and sustainable land use as well as for the creation of legislatives not only in Slovakia, but in EU, too.     

Long Term Effects of Farming System on Soil Water Content and Dry Soil Layer in Deep Loess Proifle of Loess Tableland in China

Soil water is strongly affected by land use/cover in the Loess Plateau in China. Water stored in thick loessal soils is one of the most important resources regulating vegetation growth. However, soil water in the deep loess proifle, which is critical for maintaining the function of the“soil water pool”is rarely studied because deep proifle soil samples are dififcult to collect. In this study, four experimental plots were established in 2005 to represent different farming systems on the Changwu Tableland：fallow land, fertilized cropland, unfertilized cropland, and continuous alfalfa. The soil water content in the 15-m-deep loess proifles was monitored continuously from 2007 to 2012 with the neutron probe technique. The results showed that temporal variations in soil water proifles differed among the four farming systems. Under fallow land, the soil water content increased gradually over time, ifrst in the surface layers and later in the deep soil layers. In contrast, the soil water content decreased gradually under continuous alfalfa. The distributions of soil water in deep soil layers under both fertilized and unfertilized cropland were relatively stable over time. Thus farming system signiifcantly affected soil water content. Seven years after the start of the experiment, the soil water contents in the 15-m-deep proifles averaged 23.4%under fallow land, 20.3%under fertilized cropland, 21.6%under unfertilized cropland, and 16.0%under continuous alfalfa. Compared to measurements at the start of the experiment, both fallow land and unfertilized cropland increased soil water storage in the 15-m loess proifles. In contrast, continuous alfalfa reduced soil water storage. Fertilized cropland has no signiifcant effect on soil water storage. These results suggest that deep soil water can be replenished under the fallow and unfertilized farming systems. Dry soil layers （i.e., those which have soil water content less than the stable ifeld water capacity） in the subsoil of the Changwu Tableland region can be classiifed as either temporary dry soil layers or persistent dry soil layers. Temporary dry soil layers, which typically form under annual crops, often disappear during wet years. Persistent dry soil layers generally develop under perennial vegetation. Even after removing the vegetation, persistent dry soil layers remain for several decades. This study provides information useful for the conservation and utilization of soil water resources in the Loess Tableland.     

Basic Soil Productivity of Spring Maize in Black Soil Under Long-Term Fertilization Based on DSSAT Model

Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity （BSP） is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr （1990-2011） long-term experimental data on black soil （Typic hapludoll） in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer （DSSAT）-CERES-Maize model was applied to simulate the yield by BSP of spring maize （Zea mays L.） to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined： （1） no-fertilization control （control）; （2） chemical nitrogen, phosphorus, and potassium （NPK）; （3） NPK plus farmyard manure （NPKM）; （4） 1.5 time of NPKM （1.5NPKM） and （5） NPK plus straw （NPKS）. Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value （in 1992）, but not significant under NPK （26.9% increase） and the control （8.9% decrease）. The contribution percentage of BSP showed a significant rising trend （P〈0.05） under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers （I.5NPKM and NPKM） could more effectively increase BSP compared with the inorganic fertilizer application alone （NPK） in the black soil. This study showed that soil organic matter （SOM） was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization （NPKM or NPKS） not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization （NPKM or NPKS） should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.     

Spatiotemporal Changes in Soil Nutrients:A Case Study in Taihu Region of China

The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nutrients. In this paper, we combined spatial measurements from 2 157 soil samples and geostatistical analysis to assess the spatiotemporal changes in soil organic carbon （SOC）, total nitrogen （TN）, available phosphorus （AP） and available potassium content （AK） from the first soil survey （in the 1980s） to the second soil survey （in the 2000s） in the Taihu region of Jiangsu Province in China. The results showed that average soil nutrients in three soil types all exhibited the increased levels in the 2000s （except for AK in the yellow brown soil）. The standard deviation of soil nutrient contents increased （except for TN in the paddy soil）. Agricultural production in the 20 years led to increases in SOC, TN, AP and AK by 74, 82, 89 and 65%, respectively, of the Taihu areas analyzed. From the 1980s to 2000s all the nugget/sill ratios of soil nutrients indices were between 25 and 75% （except for AK in the yellow brown soil in the 2000s）, indicating moderate spatial dependence. The ratio of AP in the yellow brown soil in the 2000s was 88.74%, showing weak spatial dependence. The spatial correlation range values for SOC, TN, AP and AK in the 2000s all decreased. The main areas showing declines in SOC, TN and AP were in the northwest. For AK, the main region with declining levels was in the east and middle of western areas. Apparently, the increase in soil nutrients in the Taihu region can be mainly attributed to the large increase in fertilizer inputs, change in crop systems and enhanced residues management since the 1980s. Future emphasis should be placed on avoiding excess fertilizer inputs and balancing the effects of the fertilizers in soils.     

华南地区壮伟环毛蚓（Amynthas robustus）和皮质远盲蚓（Amynthas corticis）对土壤酶活性和微生物学特征的影响

【目的】研究华南地区两种常见蚯蚓对水稻土和菜园土的土壤酶活性和微生物学特征的影响。【方法】选取两种生态类型蚯蚓：壮伟环毛蚓（Amynthas robustus）和皮质远盲蚓（Amynthas corticis）,接种到水稻土和菜园土中。通过分析蚯蚓对土壤过氧化氢酶、脲酶、转化酶、酸性和碱性磷酸酶以及土壤基础呼吸、微生物量碳、微生物代谢熵等微生物特征的影响,探讨其对不同土壤的生物学性状的作用。【结果】皮质远盲蚓可以显著提高水稻土基础呼吸,增强过氧化氢酶和脲酶活性,并降低酸性磷酸酶活性（P＜0.05）;两种蚯蚓均可增加菜园土脲酶活性,同时壮伟环毛蚓能够促进转化酶活性提高,而皮质远盲蚓则有利于过氧化氢酶活性增强（P＜0.05）。多元数据分析结果显示皮质远盲蚓和壮伟环毛蚓均能够显著提高两种土壤的生物学综合性状（P＜0.05）;且皮质远盲蚓对菜园土生物质量的优化作用高于壮伟环毛蚓。【结论】蚯蚓活动有助于土壤生物学质量的提高,因此其能够作为有效生物资源应用于可持续土壤管理体系。但是,蚯蚓对土壤生物学性状的改变与蚯蚓自身生态类型和土壤特征密切相关。在未来工作中,根据不同土壤特征进行蚓种筛选和适宜有机物添加十分必要。     

Changes in Organic Carbon Index of Grey Desert Soil in Northwest China After Long-Term Fertilization

Soil organic carbon （SOC）, soil microbial biomass carbon （SMBC） and SMBC quotient （SMBC/SOC, qSMBC） are key indexes of soil biological fertility because of the relationship to soil nutrition supply capacity. Yet it remains unknown how these three indexes change, which limits our understanding about how soil respond to different fertilization practices. Based on a 22-yr （1990-2011） long-term fertilization experiment in northwest China, we investigated the dynamics of SMBC and qSMBC during the growing period of winter wheat, the relationships between the SMBC, qSMBC, soil organic carbon （SOC） concentrations, the carbon input and grain yield of wheat as well. Fertilization treatments were 1） nonfertilization （control）; 2） chemical nitrogen plus phosphate plus potassium （NPK）; 3） NPK plus animal manure （NPKM）; 4） double NPKM （hNPKM） and 5） NPK plus straw （NPKS）. Results showed that the SMBC and qSMBC were significantly different among returning, jointing, flowering and harvest stages of wheat under long-term fertilization. And the largest values were observed in the flowering stage. Values for SMBC and qSMBC ranged from 37.5 to 106.0 mg kg1 and 0.41 to 0.61%, respectively. The mean value rank of SMBC during the whole growing period of wheat was hNPKM〉NPK_M〉NPKS〉CK〉NPK. But there were no statistically significant differences between hNPKM and NPKM, or between CK and NPK. The order for qSMBC was NPKS〉NPKM〉CK〉hNPKM〉NPK. These results indicated that NPKS significantly increased the ratio of SMBC to SOC, i.e., qSMBC, compared with NPK fertilizer or other two NPKM fertilizations. Significant linear relationships were observed between the annual carbon input and SOC （P〈0.01） or SMBC （P〈0.05）, and between the relative grain yield of wheat and the SOC content as well （P〈0.05）. But the qSMBC was not correlated with the annual carbon input. It is thus obvious that the combination of manure, straw with mineral fertilizer may be benefit to increase SOC and improve soil quality than using only mineral fertilizer.     

南方酸性水稻土施用硅钾肥增产效应试验

针对南方地区酸性水稻土淋溶作用强、硅钾素缺少等问题,采用大田小区试验,研究水稻土增施硅钾肥对土壤理化性状、水稻生长发育、产量及相关性状的影响,试验设硅钾肥15kg/667m2、30kg/667m2、45kg/667m2、60kg/667m2及硫酸钾9.6kg/667m2和对照6个处理,三次重复,结果表明:随着硅钾肥施用量的增加,土壤p H值也呈递增趋势,对水稻产量的影响尤为明显,分别比对照(习惯施肥)增产3.21%、12.46%、10.65%、17.05%、9.35%,说明增施硅钾肥料,不仅可以改善酸土理化性状,而且可以促进水稻增产。     

土壤水分对水、陆稻品质的影响

本文探讨了水稻和陆稻不同品种抽穗后不同时期不同程度控水,对稻米品质的影响。结果表明：不同处理对水、陆稻糙米率和精米率的影响相似,多数处理表现不同程度的提高,整精米率不同品种表现不同,各品种几乎所有处理垩白率都明显增加,各品种多数处理籽粒厚度有不同程度的增加,两个陆稻品种粒长、粒宽增加较为明显,不同处理对青米率影响不大。控水使各品种多数处理无论优势粒、劣势粒的蛋白质含量均表现增加(一些处理增加达显著或极显著水平),且水稻品种的增加幅度大于陆稻,除垦选一号陆稻外,所有水、陆稻品种中劣势粒蛋白质含量高于优势粒。     

不同土壤类型前茬作物对烤烟化学成分和品质的影响

研究了云南省陆良县红壤和水稻土前茬作物(小麦、蚕豆、绿肥、油菜)对烤烟主要化学成分和评吸质量的影响。结果表明:在水稻土条件下,相较休耕处理,前作为小麦和蚕豆时,烤烟总糖、还原糖含量适中,总氮、烟碱含量显著降低,以小麦为前作时,总氮含量仅为1.5%,烟碱含量低于2%,烤烟的感官质量评析以前作小麦和油菜最优,香气质较好,杂气少,香气风格得分均达到5,清香风格明显;在红壤条件下,以绿肥为前作时,烤烟化学成分最优,烤烟钾含量达2%以上,高于其他前作处理,烟碱含量仅为1.81%,低于以小麦、蚕豆、油菜为前作的处理,烟叶的评吸质量也以绿肥为前作时最优,烤后烟叶香气量足、燃烧性好、清香风格最明显。水稻土条件下前作为小麦,红壤条件下前作为绿肥较为适宜。