硫酸锰浸种对马铃薯品质的影响

在盆栽条件下,以马铃薯(Solanum tuberosum L.)“早大白”为材料,以浸种方式施用不同浓度硫酸锰,通过比较马铃薯块茎内各种品质指标含量的高低,研究硫酸锰对马铃薯品质的影响.结果表明:适宜浓度的硫酸锰溶液浸种处理能够改善马铃薯块茎品质,其中以浓度为0.16％的硫酸锰溶液的效果好,可提高马铃薯淀粉和维生素C...     

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.     

Plant Availability of Sulfur Added to Finished Fertilizers

As single superphosphate availability decreases due to closure of aging manufacturing plants increasing attention is being paid to alternative phosphorus (P) and sulfur (S) sources. This glasshouse study, conducted under non-leaching conditions was undertaken to evaluate the S supplying capacity of gypsum, S bentonite, elemental S (ES) and a range of P containing fertilizers and those where ES was added as a coating or incorporated. The magnitude of crop response in terms of shoot biomass to applied S fertilizer sources followed the order of sulfates > powdered ES > coated/incorporated ES > S/bentonite. These results indicate that fertilizers containing a mixture of sulfate and micronized ES (<75 µm), either incorporated within the granule or coated onto the fertilizer are agronomically effective. The results also suggest that local S coating of finished fertilizers is a feasible alternative to S incorporation undertaken at a central fertilizer plant.     

农业用硫酸镁产品指标筛选及确定

为确定农业硫酸镁产品指标,通过收集分析农业用硫酸镁企业标准及产品田间肥效试验数据,开展样品检测等。结果表明:筛选镁(Mg)、硼(B)、铁(Fe)、水不溶物、pH、水分、汞(Hg)、砷(As)、镉(Cd)、铅(Pb)、铬(Cr)为农业用硫酸镁产品指标,并确定其指标值分别为镁8.5%、硼0.3%、铁0.2%、水不溶物1.0%、pH3.0~7.0、水分含量≤7.0%、Hg含量≤5 mg·kg~(-1)、As含量≤10 mg·kg~(-1)、Cd含量≤10 mg·kg~(-1)、Pb含量≤50mg·kg~(-1)、Cr含量≤50mg·kg~(-1)。     

不同钾肥喷施对烤烟生长和产质量的影响

[目的]探索出适合烤烟K326最佳的钾肥喷施方案。[方法]研究不同种类钾肥喷施对烤烟K326生长及产质量的影响。[结果]喷施有机钾肥和硫酸钾肥均有利于烤烟的生长发育和品质的提高,但喷施有机钾肥的效果更好,能提高烟叶水溶性总糖、还原糖和钾的含量,降低总氮和烟碱含量,使初烤烟叶内在主要化学成分更趋于协调。[结论]该研究可为烤烟的钾肥施用提供参考。     

Agronomic effectiveness of rock phosphate combined with nitrogen sources in spot application: A pot experiment

Rock phosphate (RP) shows reduced dissolution in soils amended with limestone and when applied through spot application. A simple way to improve RP efficiency under these unfavorable conditions may be the combination with nitrogen (N) fertilizers which can increase the solubilization of apatite minerals and/or stimulate P uptake. In this context, we evaluated the agronomic effectiveness of a RP from Bayóvar, Peru (BY), combined with different N sources in spot application, in a clayey Oxisol (Typic Hapludox). The pot experiment consisted of a factorial scheme (3 × 2 × 2+4) in randomized block design with four replications. Treatments consisted of BY combined with three N sources (ammonium sulfate–BY+AS; urea–BY+U; potassium nitrate–BY+KN), in two forms (granulated or powdered), and in two N : P molar ratios (0.5 : 1.0 or 1 : 1) and four additional treatments [control: without P; monoammonium phosphate (MAP); powdered BY; granulated BY]. The products were incorporated into a 50 cm³ cylindrical soil volume (central and upper position in the pot: diameter 17 cm and height 15 cm) with three maize plants (Zea mays L.). Above‐ground biomass was sampled after 42 d after sowing, analyzed for N and P concentrations to calculate N and P uptake. Soil samples were taken from the cylindrical soil volume and measured for RP dissolution (ΔCa index), P availability (P‐resin index), and soil pH. Application of MAP increased soil P availability about 11 times compared with BY treatments. As a result, maize plants grew 3.8 times and absorbed 7.3 and 3.3 times more P and N compared to those fertilized with BY combined with N fertilizers. Compound fertilizers BY+AS and BY+KN had the same effect on N and P uptake, presenting an effectiveness about 12 and 19% greater than pure BY, respectively. Compound fertilizers with BY+AS were more effective in powdered form (with no N/P ratio effect), while BY+KN was more effective in granulated form and in 1 : 1 N : P ratio. BY+U combinations were less efficient in promoting plant P bioavailability than the other N sources. We conclude that Bayóvar RP has a low agronomic effectiveness for spot application, even when combined with N.     

Soil and Rice Responses to Phosphate Fertilizer in Two Contrasting Seasons on Acid Sulfate Soil

Acid sulfate soils (ASS) are characterized by low pH, aluminum (Al), and iron (Fe) toxicity and are typically deficient in phosphate (PO₄). The application of phosphorus (P) fertilizer could help reduce the level of exchangeable Al and Fe, thereby improving the rice growth and yield. Five levels of P (0, 20, 40, 60 and 80 kg phosphorus pentoxide (P₂O₅)/ha) were tested with rice varieties MTL560 in the wet season and MTL480 in the dry season. The optimum rate of P was 60 kg P₂O₅/ha for rice in the dry season and 80 kg P₂O₅/ha in the wet season. Soil testing showed at the start of the season that there was sufficient P in the soil. At the end of the season there was a reduction in soil Al and Fe in plots that had P rates above 40 kg P₂O₅/ha. It is therefore likely that P application reduced Al and Fe toxicity through precipitation and formation of Al-P and Fe-P compounds, which boasted yield, rather amending a soil P deficiency.     

氮肥对库布齐沙地柳枝稷目标产量的影响

柳枝稷是一种生物量高、防风固沙效果好,具有良好发展前景的草本能源植物。为了将暖季型的柳枝稷引种到库布齐沙地,以柳枝稷品种“BL-1”为试验材料,研究了库布齐沙地柳枝稷目标产量(生物量、粗蛋白产量、中性洗涤纤维产量、酸性洗涤纤维产量)对施用尿素和硫酸铵两种氮肥的响应。硫酸铵和尿素各设置4个施氮水平0、75、150和225 kg/hm2,每个处理设置3个重复,分别于苗期、分蘖期和拔节期施入各试验小区,施入量分别为施氮量的1/5、2/5和2/5。在柳枝稷的拔节期、孕穗期、初花期分别测定其株高、茎粗、叶面积、地上生物量。结果表明:硫酸铵和尿素的施用均可以显著提高柳枝稷的产量,施用硫酸铵后,柳枝稷的产量随着施氮量的增加而呈现逐渐增加的趋势;施用尿素后,柳枝稷的产量随着施氮量的增加出现先升高后降低的动态趋势,且产量最高点出现在施氮量为150 kg/hm2时。在施氮量为75和150 kg/hm2时硫酸铵和尿素两种肥料对柳枝稷的产量的增加程度差异不显著;在施氮量为225 kg/hm2时,硫酸铵对柳枝稷的产量提高程度显著高于尿素。柳枝稷个体大小与叶面积是影响柳枝稷产量的重要因素,氮肥的施用对于柳枝稷生长的促进作用在拔节期最明显;对于柳枝稷叶面积的促进作用在孕穗期最明显;对于柳枝稷增产的促进作用在初花期最明显。硫酸铵相较于尿素更有利于促进柳枝稷的增产。      

不同含水量天然硫酸盐盐渍土中二氧化碳和氧化亚氮的排放

Soil salinization may negatively affect microbial processes related to carbon dioxide(CO_2) and nitrous oxide(N_2O) emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity(EC) and moisture content on CO_2 and N_2O emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0–15 and 15–30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space(WFPS) at 25?C. The measured depth-weighted EC of the saturated paste extract(EC_e) across the sampling positions ranged from 0.43 to 4.65 dS m~(-1). Potential nitrogen(N) mineralization rate and CO_2 emissions decreased with increasing soil EC_e, but the relative decline in soil CO_2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N_2O emissions decreased from 133 μg N_2O-N kg~(-1) soil at EC_e 0.50 dS m~(-1) to 72 μg N_2O-N kg~(-1) soil at EC_e = 4.65 dS m~(-1). In contrast, at 90% WFPS,soil N_2O emissions increased from 262 μg N_2O-N kg~(-1) soil at EC_e = 0.81 dS m~(-1) to 849 μg N_2O-N kg~(-1) soil at EC_e = 4.65 dS m~(-1), suggesting that N_2O emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil EC_e and pattern of rainfall over the season need to be considered when up-scaling N_2O and CO_2 emissions from field to landscape scales.     

茯苓硫酸酯化多糖的制备及其核磁共振波谱分析

[目的]用不同方法制备3种茯苓多糖硫酸酯（Pachyman sulfate,PS）,并对其进行核磁共振波谱对比分析,为多糖硫酸化提供基础数据。[方法]以氯磺酸为磺化试剂硫酸化茯苓多糖制备茯苓多糖硫酸酯PS—I和PSII,以氨基磺酸为磺化试剂制备PS-Ⅲ,分析磺化反应前后和不同硫酸根取代度（Degree of sulfation,DS）的多糖碳原子化学位移的变化规律。[结果]PS—I（DS=2．80）分子所有自由羟基均发生取代反应;PS—H（DS=1．55）C-6羟基被全部酯化,C-2和C-4羟基发生部分酯化反应;PS-Ⅲ（DS=0．95）C-6和C-2羟基发生部分硫酸酯化反应。[结论]发生取代反应的碳原子化学位移移动的距离与PS的DS呈正相关,核磁共振技术能够提供多糖结构解析的关键数据。