Response of soil Olsen-P to P budget under different long-term fertilization treatments in a fluvo-aquic soil

The concentration of soil Olsen-P is rapidly increasing in many parts of China, where P budget(P input minus P output) is the main factor influencing soil Olsen-P. Understanding the relationship between soil Olsen-P and P budget is useful in estimating soil Olsen-P content and conducting P management strategies. To address this, a long-term experiment(1991–2011) was performed on a fluvo-aquic soil in Beijing, China, where seven fertilization treatments were used to study the response of soil Olsen-P to P budget. The results showed that the relationship between the decrease in soil Olsen-P and P deficit could be simulated by a simple linear model. In treatments without P fertilization(CK, N, and NK), soil Olsen-P decreased by 2.4, 1.9, and 1.4 mg kg^(–1) for every 100 kg ha^(–1) of P deficit, respectively. Under conditions of P addition, the relationship between the increase in soil Olsen-P and P surplus could be divided into two stages. When P surplus was lower than the range of 729–884 kg ha^(–1), soil Olsen-P fluctuated over the course of the experimental period with chemical fertilizers(NP and NPK), and increased by 5.0 and 2.0 mg kg^(–1), respectively, when treated with chemical fertilizers combined with manure(NPKM and 1.5 NPKM) for every 100 kg ha^(–1) of P surplus. When P surplus was higher than the range of 729–884 kg ha^(–1), soil Olsen-P increased by 49.0 and 37.0 mg kg^(–1) in NPKM and 1.5 NPKM treatments, respectively, for every 100 kg ha^(–1) P surplus. The relationship between the increase in soil Olsen-P and P surplus could be simulated by two-segment linear models. The cumulative P budget at the turning point was defined as the "storage threshold" of a fluvo-aquic soil in Beijing, and the storage thresholds under NPKM and 1.5 NPKM were 729 and 884 kg ha^(–1)P for more adsorption sites. According to the critical soil P values(CPVs) and the relationship between soil Olsen-P and P budget, the quantity of P fertilizers for winter wheat could be increased and that of summer maize could be decreased based on the results of treatments in chemical fertilization. Additionally, when chemical fertilizers are combined with manures(NPKM and 1.5 NPKM), it could take approximately 9–11 years for soil Olsen-P to decrease to the critical soil P values of crops grown in the absence of P fertilizer.

Long-term organic and inorganic fertilizations enhanced basic soil productivity in a fluvo-aquic soil

The improvement of soil productivity depends on a rational input of water and nutrients, optimal field management, and the increase of basic soil productivity（BSP）. In this study, BSP is defined as the productive capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local field management. Based on 19-yr data of the long-term agronomic experiments（1989–2008） on a fluvo-aquic soil in Zhengzhou, Henan Province, China, the decision support system for agrotechnology transfer（DSSAT ver. 4.0） crop growth model was used to simulate yields by BSP of winter wheat（Triticum aestivium L.） and summer maize（Zea mays L.） to examine the relationship between BSP and soil organic carbon（SOC） under long-term fertilization. Five treatments were included：（1） no fertilization（control）,（2） nitrogen, phosphorus and potassium fertilizers（NPK）,（3） NPK plus manure（NPKM）,（4） 1.5 times of NPKM（1.5NPKM）, and（5） NPK plus straw（NPKS）. After 19 yr of treatments, the SOC stock increased 16.7, 44.2, 69.9, and 25.2% under the NPK, NPKM, 1.5NPKM, and NPKS, respectively, compared to the initial value. Among various nutrient factors affecting contribution percentage of BSP to winter wheat and summer maize, SOC was a major affecting factor for BSP in the fluvo-aquic soil. There were significant positive correlations between SOC stock and yields by BSP of winter wheat and summer maize（P〈0.01）, and yields by BSP of winter wheat and summer maize increased 154 and 132 kg ha^（–1） when SOC stock increased 1 t C ha^（–1）. Thus, increased SOC accumulation is a crucial way for increasing BSP in fluvo-aquic soil. The manure or straw combined application with chemical fertilizers significantly enhanced BSP compared to the application of chemical fertilizers alone.

Effects of Long-term Located Fertilization on Evolution of Available Phosphorus and Phosphorus Pool in Shandong Fluvo-aquic Soil

This study was conducted to investigate the effects of long-term located fertilization on soil phosphorus,the changes of soil available phosphorus（ OlsenP）,the evolution of soil total phosphorus（ TP） and the ratio change of Olsen-P to TP（ PAC） by 33-year fertilization experiments in winter wheat-summer maize rotation system in Shandong fluvo-aquic soil. Eight treatments were designed as no fertilization（ CK）,nitrogen fertilizer（ N）,nitrogen and phosphate fertilizer（ NP）,nitrogen and potassium fertilizer（ NK）,phosphate and potassium fertilizer（ PK）,nitrogen-phosphate-potassium fertilizer（ NPK）,reduced NPK fertilizer（ N（15） PK）,and increased NPK fertilizer（ N（25） PK）. Meanwhile,eight organic fertilizer-added treatments were designed based on the application of inorganic fertilizer the same as the above ones. The results showed that TP,Olsen-P and PAC of treatments added with organic fertilizer were higher than those without organic fertilizer,and those of the treatments applied with phosphate fertilizer were higher than those of no phosphate fertilizer. With the increase of years,soil P pool decreased due to crop absorption,nutrient loss and morphological transformation and other causes under the treatments of without and only phosphate fertilizer,while remained stable under the treatments added with organic fertilizer. The PAC values were generally lower in fluvo-aquic soil,and it could be improved by the application of organic fertilizer. On the whole,the application of chemical phosphate fertilizer combined with organic fertilizer could improve the phosphorus content in soil and ensure the supply of phosphorus nutrition. This study would provide scientific basis for fertilization management and soil fertility in fluvo-aquic soil.

K^+ Adsorption Kinetics of Fluvo-Aquic and Cinnamon Soil Under Different Temperature

The K+ adsorption kinetics of fluvo-aquic soil and cinnamon soil under different temperatureswere studied. The results showed: 1) The first order equations were the most suitable forfitting the adsorption under various temperature levels with constant K+ concentration indisplacing fluid. With temperature increasing, the fitness of Elovich equation increased,while those of power equation and parabolic diffusion equation decreased; 2)the apparentadsorption rate constant ka and the product of ka multiplied by the apparent equilibriumadsorption qincreased when temperature increased, while the apparent equilibrium adsorptionqreduced; 3)temperature influenced hardly the reaction order, the order of concentrationand adsorpton site were always 1 under various temperatures, if they were taken intoaccount simultaneously, the adsorption should be a two-order reaction process; 4)theGibbs free energy change △G of potassium adsorption were negative, ranged from -4444.56to -2450.63Jmol-1,and increased with temperature increasing, while enthalpy change △H,entropy change △S, apparent adsorption activation Ea, adsorption activation energy E1and desorption activation energy E2 were temperature-independent; 5)the adsorption wasspontaneous process with heat releasing and entropy dropping, fluvo-aquic soil releasedmore heat than cinnamon soil.

Bioaccumulation of Lanthanum and Its Effect on Growth of Maize Seedlings in a Red Loamy Soil

Through a pot culture lanthanum nitrate was applied to maize seedlings grown in a red loamy soil to investigate the physiological and toxic effects of added La on the growth of crop seedlings and La bioaccumulation to help understand the environmental chemistry behaviors of rare earth element as fertilizers in soils. Compared to the control, La concentrations in shoots and especially in roots of maize seedlings increased with an increase of La in the soil. Also, with added concentrations of La≥0.75 g La kg-1 soil and≥0.05 g La kg-1 soil, the dry weight of shoots and roots of maize seedlings was significantly reduced (P≤0.05), respectively, compared with the control. Additionally, La≥0.5 g kg-1 in the soil significantly inhibited (P≤0.05) primary root elongation. Roots were more sensitive to La stress than shoots and thus could be used as a biomarker to La stress. Overall, in the red loamy soil studied, La had no significant beneficial effects on the growth of maize at the added La levels above 0.1 g kg-1 soil.

玉米秸秆还田形态对棕壤性土土壤肥力及烤烟产量品质的影响

为探究不同形态秸秆还田对棕壤性土植烟土壤肥力的影响效应,以不施秸秆为对照(CK),设置玉米秸秆粉碎1 cm(FS1)、粉碎5 cm(FS5)、粉碎10 cm(FS10)和秸秆粉末1 mm(FM)4种形态的秸秆还田试验,表征0~20 cm土层土壤物理性质、养分状况以及土壤酶活性,并综合评价土壤肥力质量以及烤烟产质量。两年试验结果表明,(1)与CK相比,秸秆还田处理均能改善土壤物理性状,可降低土壤容重2.88%~10.99%,提高田间持水量5.96%~34.02%,降低土层平均穿透阻力19.17%~25.87%,以FS5处理的降低或提升效果最显著(P<0.05);(2)不同形态秸秆还田对土壤碳氮的提升具有差异,FS5和FM处理能较CK显著增加土壤总有机碳含量74.08%和44.84%(P<0.05),FS1、FS5和FS10处理分别显著增加微生物量碳含量80.79%、125.31%和70.39%(P<0.05),以FS5处理增加量最高,同时能分别提升土壤全氮、碳氮比和硝态氮含量34.40%、20.22%和749.06%(P<0.05);(3)与CK相比,不同形态秸秆还田分别显著提升土壤蔗糖酶和纤维素酶活性52.40%~222.39%和6.19%~26.88%,以FS5处理的提升幅度最高(P<0.05);(4)土壤肥力评价结果表明,FS5处理综合质量得分最高(0.72),可作为提升棕壤性土植烟土壤肥力的有效秸秆形态,其中,土壤硝态氮、土壤微生物量碳和纤维素酶是影响土壤肥力的关键因子;(5)FS1和FS5处理可增加烤后烟产量8.46%~23.34%。综上所述,不同秸秆还田形态在短期内可改善棕壤性土植烟土壤的理化性状和酶活性,其中以秸秆粉碎5 cm还田效果较好,可实现土壤综合肥力的快速提升。

Combined effects of two sulfonylurea herbicides on soil microbial biomass and N-mineralization

The interaction effect of two sulfonylurea herbicides, bensulfuron methyl (B) and metsulfuron methyl(M), were tested on microbial biomass C, N, N mineralization and C/N ratio in a loamy sand soil. The herbicides were applied at various levels of: control (B0M0), 0.01 and 0.01 (B1M1), 0.01 and 0.1 (B1M2), and 0.01 and 1.0 (B1M3) μg/g soil. Determinations of soil microbial biomass C, N and N mineralization contents were carried out at 1, 3, 5, 7, 10, 15, 25 and 45 days after herbicides application. The results showed that the soil microbial biomass C (C mic ) and microbial biomass N (N mic ) decreased consistently with the increasing rates of herbicides. The results further indicated that B1M1 and B1M2 caused a significant reduction in C mic and N mic within first 10 and 7 days of incubation, respectively, as compared with the control. These reductions in C mic and N mic were also significant ( P =0.05) with B1M3 application especially within first 15 days of incubation. A significant reduction in N mineralization (N min) was observed with high doses (B1M2, B1M3) of herbicides within first 5 days of incubation, while low rate (B1M1) failed to produce any significant effect. An increase in the soil microbial biomass C:N ratio was also noted.

Effect of climate change on the trends of evaporation of phreatic water from bare soil in Huaibei Plain, China

When the soil condition and depth to water table stay constant, climate condition will then be the only determinant of evaporation intensity of phreatic water from bare soil. Based on a series of long-term quality-controlled data collected at the Wudaogou Hydrological Experiment Station in the Huaibei Plain, Anhui, China, the variation trends of the evaporation rate of phreatic water from bare soil were studied through the Mann-Kendall trend test and the linear regression trend test, followed by the study on the responses of evaporation to climate change. Results indicated that in the Huaibei Plain during 1991-2008, evaporation of phreatic water from bare soil tended to increase at a rate of 5% on monthly scale in March, June and July while in other months the increase was minor. On the seasonal basis, the evaporation saw significant increase in spring and summer. In addition, annual evaporation tended to grow evidently over time. When air temperature rises by 1 °C, the annual evaporation rate increases by 7.24–14.21%, while when the vapor pressure deficit rises by 10%, it changes from-0.09 to 5.40%. The study also provides references for further understanding of the trends and responses of regional evapotranspiration to climate change.

Dynamic response of chlorsulfuron herbicide to nitrogen mineralization and the ratio of microbial biomass nitrogen to nitrogen mineralization in the soil

A laboratory incubation experiment was conducted to elucidate the effect of chlorsulfuron herbicide on nitrogen mineralization and the ratio of microbial biomass nitrogen to nitrogen mineralization (N mic /N min ratio) in loamy sand soil.The herbicide was applied at four levels that were control, field rate 0\^01 (FR), 10 times of field rate 0\^1(10FR),and 100 times of field rate 1\^0 (100FR) μg/g soil. Determinations of N\|mineralization and microbial biomass\|N content were carried out 1,3,5,7,10,15,25 and 45 days after herbicide application. In comparison to untreated soil, the N\|mineralization decreased significantly in soil treated with herbicide at levels 10FR and 100FR within the first 5 days incubation. A more considerable reduction in the N mic /N min ratio was observed in the herbicide treated soil than the non\|treated control.Among the different treatment of chlorsulfuron, 100FR displayed the greatest biocidal effect followed by 10FR and FR,showing their relative toxicity in the order of 100FR>100FR>FR.The results indicated that the side effect of this herbicide on N\|mineralization is probably of little ecological significance.

Response of plant physiological parameters to soil water availability during prolonged drought is affected by soil texture

Soil water deficit is increasingly threatening the sustainable vegetation restoration and ecological construction on the Loess Plateau of China due to the climate warming and human activities.To determine the response thresholds of Amygdalus pedunculata(AP)and Salix psammophila(SP)to soil water availability under different textural soils,we measured the changes in net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentration(Ci),leaf water potential(ψw),water use efficiency(WUE)and daily transpiration rate(Td)of the two plant species during soil water content(SWC)decreased from 100%field capacity(FC)to 20%FC in the sandy and loamy soils on the Loess Plateau in the growing season from June to August in 2018.Results showed that Pn,Gs,WUE and Td of AP and SP remained relatively constant at the beginning of soil water deficit but decreased rapidly as plant available soil water content(PASWC)fell below the threshold values in both the sandy and loamy soils.The PASWC thresholds corresponding to Pn,Gs and Ci of AP in the loamy soil(0.61,0.62 and 0.70,respectively)were lower than those in the sandy soil(0.70,0.63 and 0.75,respectively),whereas the PASWC thresholds corresponding to Pn,Gs and Ci of SP in the loamy soil(0.63,0.68 and 0.78,respectively)were higher than those in the sandy soil(0.58,0.62 and 0.66,respectively).In addition,the PASWC thresholds in relation to Td and WUE of AP(0.60 and 0.58,respectively)and SP(0.62 and 0.60,respectively)in the loamy soil were higher than the corresponding PASWC thresholds of AP(0.58 and 0.52,respectively)and SP(0.55 and 0.56,respectively)in the sandy soil.Furthermore,the PASWC thresholds for the instantaneous gas exchange parameters(e.g.,Pn and Gs)at the transient scale were higher than the thresholds for the parameters(e.g.,Td)at the daily scale.Our study demonstrates that different plant species and/or different physiological parameters exhibit different thresholds of PASWC and that the thresholds are affected by soil texture.The result can provide guidance for the rational allocation and sustainable management of reforestation species under different soil conditions in the loess regions.

Effects of Long-term Located Fertilization on the Physico-chemical Property of Soil Humus

A systematic study concerning the effects of a long-term stationary fertilization on content and property of soil humus in fluvo-aquic soil sampled from Malan Farm, Xinji City, Hebei, and arid red soil and paddy red soil sampled from the Institute of Red Soil, Jinxian County, Jiangxi was conducted. The results showed that long-term fertilization had effects not only on the content and composition of soil humus, but also on the physico-chemical property of humus. With applying organic manure or combined application of organic manure and chemical fertilizer, E4 and E6 values of humic acid decreased in fluvo-aquic soil and arid red soil, but increased in paddy red soil. In paddy red soil, E4 and E6 values of humic acid increased also with a single application of chemical fertilizer, but E4 and E6 values had less change of humic acid in fluvo-aquic soil and arid red soil. The effects on the visible spectroscopic property of f ulvic acid were different from that of humic acid. Long-term application of organic manure or combined application of organic manure and chemical fertilizer could increase E4 and E6 values of f ulvic acid in three types of soil. Single application of chemical fertilizer had less effect on the E4 and E6. Long-term fertilization could also influence the ultraviolet spectroscopic property of humus. With a single application of organic manure or combined application of organic manure and chemical fertilizer, the ultraviolet absorbance of humic acid and f ulvic acid increased in the three types of soil. But this effect was obvious only in short wave length, and the effect could decrease if the wave length increased. With a single application of chemical fertilizer the ultraviolet absorbance of fulvic acid could increase, but it of humic acid increased only in fluvo-aquic soil. Long-term application of organic manure or combined application of organic manure and chemical fertilizer could increase the content of total acidic groups, carboxy groups and phenolic hydroxy groups of humic acid and fuvic acid in the three types of soil. Single application of chemical fertilizer had less effect on the content of total acidic groups, carboxy groups and phenolic hydroxy groups of humic acid and fuvic acid in the three types of soil.

Evaluation of Shear Strength and Cone Penetration Resistance Behavior of Tropical Silt Loam Soil under Uni-Axial Compression

Laboratory investigations were conducted to study strength characteristics of silt loam soil of Ilorin, Kwara State, Nigeria, under uni-axial compression tests. The main objective of this study was to evaluate the effects of applied pressure and moisture content on strength indices such as bulk density, penetration resistance and shear strength of the soil and to develop relationships between the strength indices for predictive purposes necessary in soil management. The compression was carried out at different moisture contents determined according to the consistency limits of the soil. The applied pressure ranged from 75 to 600 kPa. Values of bulk density, penetration resistance and shear strength increased with increase in moisture content up to peak values after which the values decreased with further increase in moisture content. Regression models were used to describe the trends in the results for the soil. Results also showed that bulk density and soil strength normally regarded as indicators of soil quality are affected by moisture content and applied pressure and that these properties can be predicted using the models generated from the study.

Evaluation of the Forest Reclamation of the Anthroposoil Dump at the Bilina Mines Created from Marlstone

When reclaiming the surface of the Radovesická dump in the North Bohemian brown coal basin, the most commonly used marls and marlstones are extracted in the foreland of filled-in territory. The most frequent reclamations are the formation of overgrown and humus anthroposoil. The soil properties of the anthroposoils for forestry purposes and the growth vitality of a broader assortment of woody plants in the age of 12 - 14 years are evaluated. It has been found that the very good growth vitality on these anthroposoils is shown by most of the trees of domestic origin (Populus nigra L., Acer pseudoplatanus L., Pinus sylvestris L., Alnus glutinosa (L.) Gaertn., Fraxinus excelsior L., Betula verrucosa Ehrh., Quercus robur L., Tilia cordata Mill.), including some of the tree species introduced (Larix decidua L., Pinus nigra Arn.) and reclamations of atypical atrophic soil horizons did not negatively affect their development.

干湿交替与水饱和条件下轮南壤土中X80钢焊管的腐蚀行为

选择取自轮南油田的壤土作为腐蚀介质,在干湿交替和水饱和条件下对X80钢焊管进行室内模拟腐蚀试验,对比研究了母材和焊缝试样的腐蚀速率、腐蚀形貌和腐蚀产物。结果表明:试验钢在干湿交替条件下的腐蚀速率是水饱和条件下的2~48倍,且母材比焊缝更耐蚀;母材和焊缝试样在水饱和环境下均以轻微的全面腐蚀为主,在干湿交替条件下呈现土壤板结形貌,存在大量腐蚀坑;水饱和条件下,母材表面腐蚀产物内层薄且致密,外层分散出现龟裂,焊缝表面腐蚀产物内层已出现龟裂;干湿交替条件下,母材和焊缝表面腐蚀产物均存在裂缝。

蚯蚓改良水浇地土壤入渗性能及影响因素分析

【目的】探究蚯蚓不同生态类型和密度对水浇地土壤水分入渗特征的影响。【方法】选取表栖型赤子爱胜蚓(Eisenia fetida)和深栖型参状远盲蚓(Amynthas aspergillum)为研究对象,以无蚯蚓土壤处理为对照,采用一维定水头土柱模拟试验,探究蚯蚓不同生态类型和密度(低密度4 g·kg^(-1),高密度8 g·kg^(-1))对土壤湿润锋、累积入渗量、入渗速率、含水率的影响及其与土壤性状的关系,并利用Philip模型和Kostiakov模型拟合分析土壤水分入渗规律。【结果】(1)在相同时间内,蚯蚓明显降低湿润锋推进距离、推进速率、累积入渗量及入渗速率,尤其是低密度参状远盲蚓影响最为显著(P<0.01),且低密度蚯蚓的入渗性能较高密度蚯蚓处理差。(2)各处理入渗结束后,土壤含水率存在差异,参状远盲蚓极显著提高土壤含水率(P<0.01),且低密度处理最佳。(3)蚯蚓通过改变土壤的理化性质来降低土壤水分的入渗性能,其中电导率(Electricity conductivity,EC)值、有效磷(Available phosphorus,AP)值和砂粒为土壤水分入渗的主要驱动因素。(4)与Philip模型拟合结果相比,采用Kostiakov模型拟合效果更适用,对参状远盲蚓处理土壤入渗过程的拟合精度(RMSE≤4.80 mm)更高,且参状远盲蚓极显著降低了累积入渗量衰减程度(P<0.01)。【结论】经赤子爱胜蚓和参状远盲蚓改良后的水浇地土壤(壤砂质地),水分入渗性能降低,但对水分的蓄持能力增加。在改良水浇地土壤时,添加低密度的参状远盲蚓有利于土壤持水。

保水剂对土壤持水特性的影响

利用张力计和恒温脱水动力学方法 ,研究了不同剂量保水剂 (聚丙烯酰胺和水解淀粉 )施入轻壤质潮土后土壤持水性质的变化 .结果表明 ,在土壤低吸力段 (0～ 80kPa) ,随保水剂用量的增加 ,土壤持水容量增大 ,从而增加了作物可利用的有效水 ;在相同含水量时 ,土壤水能态随保水剂用量增大而降低 ;但在相同水分能态下 ,土壤含水量随保水剂的增加而明显增大 .施用保水剂后 ,土壤可在较长时间内保持较高的水分含量 ;且随保水剂用量增加 ,土壤容重下降 ,总孔隙度和毛管孔隙度则呈上升趋势 ;土壤凋萎系数虽有增大趋势 ,但增幅很小 ,土壤有效水容量明显增大 .土壤中加入 0 5 %的聚丙烯酰胺或0 2 5 %～ 0 5 %的水解淀粉 。

砂壤质潮土钾肥施用方式及与锌、硼配施对强筋小麦产量及品质的影响

通过大田试验研究了潮土区砂壤质土壤强筋小麦钾肥不同施用方式和抽穗期喷施微量元素的效果。结果表明,施用钾肥能够提高强筋小麦穗粒数和千粒重,表现出明显的增产效果。灌浆期喷施钾、锌、硼肥,可以不同程度地提高小麦旗叶的硝酸还原酶(NR)、谷丙转氨酶(GPT)活性,改善小麦的营养品质和加工品质。其中,钾和锌肥对小麦品质的影响最大,可以提高粗蛋白、沉淀值、吸水量、形成时间和稳定时间。喷锌肥可以提高沉淀值、湿面筋、吸水量和稳定时间。喷钾肥可使蛋白质、沉淀值、吸水量、稳定时间增加。

碳、氮物质对水稻田土壤甲烷氧化活性影响的研究

研究了碳素和氮素物质对黄松田土壤中甲烷氧化菌种群及其甲烷氧化活性的影响 .结果表明 ,加入不同碳素或氮素物质对黄松田土中甲烷氧化菌种群的数量变化无显著性影响 ,但对土壤氧化外源甲烷活性却具有显著性影响 .且不同浓度的同一物质对黄松田土壤氧化外源甲烷速率的影响也不相同 .甲烷氧化代谢途径中的中间产物 (甲醇和甲酸 )较非甲烷氧化代谢途径中的中间产物和能促进土壤产甲烷菌产甲烷活性的碳源物质 (酵母膏、葡萄糖和乙酸 )可更强烈地抑制土壤氧化外源甲烷的活性 .有机氮素物质对黄松田土的甲烷氧化速率的影响要较无机氮素物质弱 .在无机氮素物质中 ,硝酸盐对土壤氧化外源甲烷活性的抑制强度要强于铵盐类物质 ,NH3 要比NH4 + 对甲烷氧化菌的甲烷氧化活性具有更强的抑制作用 .一旦黄松田土的甲烷氧化活性受到碳、氮物质的抑制 ,恢复其氧化外源甲烷活性就需要较长时间 .且受到抑制的程度越强 。

测墒补灌与氮肥运筹对小麦品种水分利用的影响

为探明不同小麦品种对水分条件的响应,以矮抗58和周麦18为材料,在通许县开展了壤质潮土测墒灌溉与氮肥运筹配合对小麦水分利用的影响研究。结果表明,小麦分蘖-返青期(11月15日-2月15日)耗水比例较低,其中重度胁迫和充分灌溉处理矮抗58高于周麦18,轻度胁迫处理则低于周麦18;返青-抽穗期(2月15日-4月15日)耗水明显增加,矮抗58高于周麦18;抽穗-成熟期(4月15日-6月10日)品种间差别较小。矮抗58总体耗水量较周麦18略高,轻度胁迫有利于降低耗水量,其中矮抗58轻度胁迫处理与充分灌溉处理相比耗水量减少18.89~104.45 mm,周麦18则减少10.57~53.22 mm,但周麦18拔节+灌浆和返青-拔节+扬花2次追肥两处理分别增加11.26,30.45 mm。矮抗58的水分利用效率,除了重度胁迫返青-拔节+扬花2次追肥处理和充分灌溉不追肥处理外,均高于周麦18,重度胁迫时提高0.49~3.08 kg/(mm·hm^2),充分灌溉时提高0.23~2.82 kg/(mm·hm^2),轻度胁迫时提高1.26~3.27kg/(mm·hm^2)。矮抗58以扬花-灌浆1次追肥和拔节期+灌浆期2次追肥效果较好;周麦18则以返青-拔节+扬花2次追肥和返青-拔节1次追肥效果较好。说明不同小麦品种间控水时间和施肥时间有一定的差异。

壤质潮土长期施钾对小麦玉米轮作制作物钾吸收的影响

在辛集马兰农场进行钾肥定位试验,研究小麦-玉米轮作制度长期施钾对钾养分吸收的影响。试验开始于1992年秋天,共设4个处理,分别为只施氮磷肥的对照（NP）;在对照基础上加施秸秆（NPSt）;在对照基础上加施钾肥（NPK）;在对照基础上加施秸秆和钾肥（NPKSt）。4次重复,顺序排列,小区面积50 m2。结果表明：作物的籽粒年吸钾量与肥料中钾的施入量以及作物籽粒和秸秆产量呈显著或极显著正相关。作物籽粒钾吸收量随K2O施入量的增多而增多,与施入的速效钾形态无关。作物籽粒钾含量与钾肥的施入量相关关系不显著。在北方壤质潮土小麦玉米轮作制土壤中,小麦籽粒年均含钾量在4.99~5.13 g/kg,玉米籽粒的年均含钾量在3.75~3.93 g/kg。在壤质潮土小麦轮作制条件下,当施入一定量外源钾肥时,单位面积小麦植株地上部分和玉米植株地上部分K2O养分吸收量差异不大。小麦季K2O吸收量为140.37 kg/hm2,玉米季为138.23 kg/hm2,据此可有效指导该类型区的钾肥投入。