Distribution Characteristics of the Heavy Metal Cd in the Irrigation Water-Cultivated Soil-Fertilizer-Crop Ecosystem

Shuangqiao Countryside of Neijiang City in hilly ground area in the midland of Sichuan Province was chosen as the study geographic area to survey and analyze the content distribution characteristics of the Cd in the irrigation water,ground water mud,surface layer cultivated soil,profile soil and the fertilizer which were often used in the locality,and in different crops set earth,fructification as well. The results showed that the content of Cd in the irrigation and ground water mud respectively comply with the national agriculture use irrigation standard and the contamination control standard value in agriculture use mud ( GB4284-84) respectively. The average contents in the surface cultivated soil and each layer of soil profile are all above the background level of Chengdu economic region ( 44% ) ,referring to a large scale pollution risk. The average value of Cd element in fertilizer was 1. 81 μg / g,which was higher than the third class standard of national soil environment quality; The average content of Cd element in the crops' set earth was 0. 410-0. 439 μg / g,which was higher than the second class standard of national soil environment quality and there was a measure of cumulation; The average values of Cd in crops' fructificationwas all below the primary standard of national soil environment quality,and the bioamplification coefficient sorting was CF( Cdpeanut) > CF( Cdcitrus) > CF ( Cdrice) > CF( Cdcorn) . Irrigation water had little influence on the soil Cd pollution,where fertilizer using was closely related to the Cd pollution in the surface cultivated soil in the survey area and had a certain influence on the Cd cumulation in the crops. The sorption and enrichment of crops' set earth and fructification was obviously different.

Effect of Different Levels of Water Soluble Phosphorus in Complex Fertilizers on Crop Productivity and Soil Health

Field experiments were undertaken on sandy soils with three cropping systems at Giridih,Jharkhand,India for two years during 2012-2014.The experiments were executed in split plot design by assigning water soluble phosphorus(WSP)fertilizers in main-plot and recommended dose of phosphorus(RDP)in sub-plot with three replications.The maximum economical yield of rice(4705 kg/ha),baby corn(842 kg/ha)and Chickpea(920 kg/ha)were recorded with the application of 30%WSP.The maximum economical yield of successive crops-wheat(3185 kg/ha),mustard(1720 kg/ha)and groundnut(1578 kg/ha)were recorded with the application of 30%WSP and 100%RDP treatment.Almost similar trends were noticed in terms of by-product yield,nutrient uptake and residual soil fertility status.All the levels of WSP(30%-89%)in complex fertilizers were found to be equally effective for grain yield,straw yield,nutrient uptake,and residual soil fertility.

Effect of water and fertilizer coupling optimization test on water use efficiency of rice in black soil regions

How to improve the water use efficiency of rice in black soil regions was studied. The black soil region in paddy fields was chosen as the research object. The research showed the fertilizer coupling mathematical model with N,P,K,irrigation water( W) and water use efficiency( WUE),which was set up under the condition of controlled irrigation with quadratic D- 416 optimized saturation design. The results show that the decending order of single factor' s influence on the WUE was N,K,P and W. All the interactions between N&P,N&K,N&W,K&P,P&W and K&W on the WUE were raised initially,and when reached a certain value,they began to decline. The decending order of each interaction on the WUE was K&P,K&W,N&K,N&P,P&W and N&W. When the WUE was targeted within 1. 8- 2. 5 kg / km^3,an optimized proportion plan was obtained in the 95% confidence interval,i. e. N 87. 76- 103. 32 kg / hm^2,K_2 O 52. 37- 66. 53 kg / hm^2 and P_2O_536. 80- 46. 71 kg / hm^2. Furthermore,the late tillering of the soil moisture content was 70. 07%- 72. 57% of the saturated moisture content.

Effects of level soil bunds and stone bunds on soil properties and its implications for crop production: the case of Bokole watershed, Dawuro zone, Southern Ethiopia

Level soil bunds (LSB) and stone bunds (SB) have been widely implemented in the Bokole watershed since 2000 through support of the World Food Program (WFP). However, the performance of them against the target of the structure has not been studied. This study analyzed the effect of LSB and SB on selected soil properties, when compared with nonterraced cropland. The Bokole watershed was divided into two units. From upper watershed, three croplands with LSB (aged 4, 6, and 9 years) and three nonterraced croplands each adjacent to one of the LSB were selected. Similarly, in lower watershed, SB aged 4, 6, and 8 years and three nonterraced croplands each adjacent to one of the SB were selected. From each cropland with LSB and SB, three composite soil samples (rep licates) were collected systematically in X designed rectangular plot. From each nonterraced cropland, three composite soil samples (replicates) were collected in X designed square plot. A total of 36 soil samples were analyzed for Soil Organic Carbon (SOC), Total Nitrogen (TN), Available Phosphorus (AP), Available Potassium (AK), pH, and Cation Exchange Capacity (CEC) following standard laboratory procedures. Most soil parameters were not significantly different in cropland with LSB and SB compared to nonterraced. However, in LSB aged 4 years and SB aged 6 years AP and pH were significantly less than their adjacent-nonterraced cropland. In SB aged 8 years, SOC, AP, AK, and pH were also significantly less than adjacent-nonterraced cropland. Past erosion, and past land uses are likely factors contributed to the observed result. It was inferred that the mean con tribution of LSB and SB alone for crop production with regard to analyzed soil parameters was not significant in the considered sites. Additional soil fertility management practices should be incorporated for better effect.

Planning for Integrative Management of Wastewater Disposal, Irrigation Water Supply and Fertilizer Use: A Case Study in an Arid Land of China

This work is a trans-disciplinary undertaking aiming at innovative water management in arid and semi-arid regions. Based on field studies on soil bacterial communities and irrigation water quality in an arid region of China where wastewater has been used for agricultural production decade long, this paper is intended to propose an integrative management scheme combining wastewater reuse in agriculture, wise use of wetlands and fertilizer management as an engine toward achieving sustainable development in arid and semi-arid regions. This study was also designed to address a key but very much neglected question about wastewater reuse in irrigation: does wastewater irrigation lead to reduction of chemical fertilizer use and increase of crop yield? Through a questionnaire, it revealed that there was a misperception among farmers about wastewater, which led to no-reduction or even increase in fertilizer use with wastewater irrigation as compared with river water irrigation. It also showed that crop yield was not increased with wastewater irrigation under the current practice. Besides, it sheds some light on an underreported health concern.

GROUND WATER QUALITY IN THE INDUS PLAINS OF PAKISTAN AND ITS USE FOR CROP PRODUCTION DURING RECLAMATION OF SALINE-SODIC SOILS

The Indus Plains of Pakistan lies between 23°to 37°latitude and 61°to 76°longi-tude in the northern hemisphere. The total Canal Commanded Area (CCA) is about 13.50million hectares of which 11.21 million hectares are cultivated. At present, 103 millionacre-feet river flow is diverted into irrigation canals. In addition, 42 million acre feet of thegroundwater are being pumped through 257697 tubewells to supplement the canal supplies.

Soil physical quality as influenced by long-term fertilizer management under an intensive cropping system

In China’s major rice(Oryza sativa L.)production regions,the traditional fertilization modes are challenged by the continued decrease in manure and increase in mineral fertilizer.However,limited information exists on the influences of long-term fertilizer management on soil organic carbon(SOC)and soil physical properties under the intensive rice production system in southern China.The objective of this study was to characterize the changes of soil physical properties as related to mineral fertilizer,crop residues,and manure application based on a long-term field experiment.The experiment,initiated in 1986,has five treatments:unfertilized,mineral fertilizer alone,rice residues plus mineral fertilizer,low manure rate plus mineral fertilizer,and high manure rate plus mineral fertilizer.The cropping system consists of barley(Hordaum vulgare L.),early rice,and late rice,three crops in a year.In May 2006,after barley harvest,soil samples were collected from the 0~10 cm and 10~20 cm layers to determine SOC concentration,aggregate size distribution,bulk density(rb),saturated hydraulic conductivity(Ks),and soil water characteristic curves(SWCC).The results indicated that manure significantly reducedrb,increased SOC concentration,soil aggregation,Ks,transmission and storage porosity,as well as water retention capacity.Combined application of crop residue and mineral fertilizer also improved soil physical properties,but the improvement by mineral fertilizer alone was limited.Correlation analysis demonstrated that S,the slope of the SWCC at its inflection point,was closely associated with the selected physical parameters,suggesting S was an effective parameter for soil physical quality evaluation.Nevertheless,in applying the S-theory,a unified approach to define the residual water content should be considered.

Reducing water and nitrogen inputs combined with plastic mulched ridge-furrow irrigation improves soil water and salt status in arid saline areas,China

Plastic mulched ridge-furrow irrigation is a useful method to improve crop productivity and decrease salt accumulation in arid saline areas.However,inappropriate irrigation and fertilizer practices may result in ecological and environmental problems.In order to improve the resource use efficiency in these areas,we investigated the effects of different irrigation amounts(400(I1),300(I2)and 200(I3)mm)and nitrogen application rates(300(F1)and 150(F2)kg N/hm^(2))on water consumption,salt variation and resource use efficiency of spring maize(Zea mays L.)in the Hetao Irrigation District(HID)of Northwest China in 2017 and 2018.Result showed that soil water contents were 0.2%-8.9%and 13.9%-18.1%lower for I2 and I3 than for I1,respectively,but that was slightly higher for F2 than for F1.Soil salt contents were 7.8%-23.5%and 48.5%-48.9%lower for I2 than for I1 and I3,but that was 1.6%-5.5%higher for F1 than for F2.Less salt leaching at the early growth stage(from sowing to six-leaf stage)and higher salt accumulation at the peak growth stage(from six-leaf to tasseling stage and from grain-filling to maturity stage)resulted in a higher soil salt content for I3 than for I1 and I2.Grain yields for I1 and I2 were significantly higher than that for I3 and irrigation water use efficiency for I2 was 14.7%-34.0%higher than that for I1.Compared with F1,F2 increased the partial factor productivity(PFP)of nitrogen fertilizer by more than 80%.PFP was not significantly different between I1F2 and I2F2,but significantly higher than those of other treatments.Considering the goal of saving water and nitrogen resources,and ensuring food security,we recommended the combination of I2F2 to ensure the sustainable development of agriculture in the HID and other similar arid saline areas.

覆土浅埋滴灌玉米分阶段亏水条件下AquaCrop与Dual Crop Coefficient模型精度对比研究

近年来,西辽河流域地下水超采问题日益突出,改进灌溉技术降低农业用水可有效解决这一问题,但该技术缺乏科学的水分管理方法及适宜的理论模型。基于单阶段及多阶段亏水情形试验,对比同类农田水分模型精度,优选阶段性亏水管理辅助模型。研究设置7个玉米分阶段亏水调控处理,于2018、2019年进行田间小区试验,取得2个同类模型的本地化参数并比较其模拟精度。结果表明,AquaCrop和双作物系数模型可相近表达玉米冠层发育到最大而未开始衰减期间土壤水分的消耗过程,而对快速生长期与后期1m土层贮水量的模拟差异大。AquaCrop模型在土壤贮水量偏低时高估其实测值,其他情形正负偏差分布相对均匀,双作物系数模型多数情形低估其实测值。AquaCrop模型描述玉米各阶段蒸散量因亏水情形而变化能力优于双作物系数模型。AquaCrop模型和双作物系数模型的标准均方根误差平均值在模拟1 m土层贮水量时分别为4.494%~8.443%、6.017%~8.626%,在模拟蒸散量时分别为8.158%~9.510%、5.980%~15.022%。综合来看,AquaCrop模型表现更好,推荐作为适宜西辽河流域覆土浅埋滴灌玉米水分管理模型。研究可为该区域覆土浅埋滴灌种植玉米选出适宜的水分管理模型,理解新技术条件下玉米分阶段亏水调控机制及田间灌溉管理优化提供参考。

贵州省惠水土壤-灌溉水-雨水-大气降尘中Cd、As等微量元素特征及来源讨论

【研究目的】土壤-水体-大气降尘中Cd、As等微量元素成因来源、富集规律为环境地质研究焦点,开展惠水土壤-灌溉水-雨水-大气降尘系统中Cd、As等微量元素迁移与富集的定量研究,对该地区农业生产和农产品种植具有重要意义。【研究方法】以贵州省惠水县表层土壤、灌溉水、雨水和大气降尘样品为研究对象,分析样品中的Cd、As微量元素地球化学特征。【研究结果】结果表明:研究区以酸性土为主,147件表层土壤样品中元素Cd与As、Cr、Hg、Mn、Ni、Pb、Zn、pH呈正相关关系,与Cu、Se呈负相关关系;34件灌溉水样品中含量主要为As、B、F-、Se、Zn,灌溉水重金属元素单因子污染指数和内梅罗综合指数等级为1级,属清洁范围,表明灌溉水水质均达标;5件雨水和大气降尘样品中,大气降尘主要为As、Cd、Cr、Hg、Pb,雨水中主要为As、B、Cd、Cr^(6+)、F^(-)、Ge、Hg、Pb、Se、Zn。【结论】评价结果显示:土壤单因子污染指数Cd指数最高,内梅罗综合污染指数大小为羡塘镇红旗村>芦山镇羊马村>涟江街道大坡村>好花红镇好花红村>摆金镇立新村;灌溉水水质均达标,无重金属元素污染;大气降尘年通量密度平均值大小顺序分别为B>Se>Pb>Zn>Cr>As>F>Cd>Ge>Hg。研究区大气降尘总量平均值89 g·m^(-2)·a^(-1),与中国一些省市地区相比较,总量略低;表层土壤、大气降尘之间对比表明:表层土壤与年雨水通量相对比来看,Cd、Cr、Pb、Zn富集,Se亏损,表明雨水对Se的贡献较大;大气降尘对比于雨水,除Hg外,大气降尘其他元素都高于雨水;大气降尘年通量和表层土壤平均值比较,除Se外,其他元素均亏损;大气降尘年通量与灌溉水含量相对比,As、Hg、Se富集,Cr亏损。表层土壤重金属元素Cd污染来自于地质背景、工业三废、燃煤的综合来源;大气降尘主要来源于燃煤尘和交通尘。

Soil physical properties,nutrients,and crop yield with two-year tillage rotations under a winter wheat-summer maize double cropping system

Winter wheat and summer maize were planted from 2015-2017 to study the effects of different rotational tillage patterns on soil physicochemical properties,crop yield,water content,and fertilizer utilization.The tillage treatments were designed as wheat subsoiling-maize no tillage(WS-MN),wheat rotary tillage-maize subsoiling(WR-MS),wheat subsoiling-maize subsoiling(WS-MS),and conventional wheat rotary tillage-maize no tillage(WR-MN)as a control.Among the four treatments,WS-MN and WR-MS were single-season subsoiling treatments,and WS-MS was a two-season subsoiling treatment.The average soil bulk density decreased by 7.6%in the single-and double-season subsoiling groups compared to the WR-MN group,and the total porosity and noncapillary porosity increased by 10.7%and 12.2%,respectively.Single-or double-season subsoiling treatment was not conducive to water storage in the 0-20 cm soil layer but increased the water content of the 20-140 cm soil layer,and the average soil water content of the 0-140 cm layer was increased by 11.6%in the two-growing season treatment groups compared with the WR-MN group.In WS-MS and WS-MN groups compared with the WR-MN group,the soil ammonium nitrogen content was increased by an average of 18.6%in 0-20 cm soil and 16.8%in 20-100 cm soil;soil nitrate-nitrogen content was decreased by 13.5%in 0-100 cm soil;total organic carbon and microbial carbon contents in the 15-30 cm soil were increased by 18.1%and 12.7%,respectively;and soil urease,catalase,and alkaline phosphatase activities were increased by 46.1%,15.2%,and 23.1%,respectively.Annual crop yield and water use efficiency increased by 8.9%and 15.0%,respectively,in both the single-and double-season subsoiling treatment groups.This study demonstrated the advantages of subsoiling tillage and suggested that it is suitable for crop cultivation in the Haihe Plain,China.

Different Fertilization Modes of Sugarcane in Latosolic Red Soil of Guangxi

[Objectives] This study aimed to compare the effects of water-fertilizer integrated drip irrigation modes and traditional fertilization mode on growth,yield,production costs and economic benefit of sugarcane in latosolic red soil of Guangxi. [Methods]A field test was conducted. [Results] The agronomic traits and comprehensive economic benefit of sugarcane under the water-fertilizer integrated drip irrigation modes were superior to those under the traditional fertilization mode. Among them,the comprehensive economic benefit of sugarcane with special granular fertilizer as the base fertilizer and water-fertilizer integrated drip irrigation as topdressing were the highest,increased by 15 813 kg/ha,an increase of 15. 8%. Considering the cost input,the comprehensive economic benefit increased by 5 676 yuan/ha. [Conclusions]Taking the production cost,economic benefit and input-output ratio into account,it is recommended to promote the application of water-fertilizer integrated drip irrigation mode in bases with water and fertilizer equipment conditions.

不同钾肥对再生水灌溉条件下土壤-作物系统Cd的影响

为了探明再生水灌溉条件下不同施钾肥处理对土壤-作物系统Cd的影响及差异性,通过田间微区试验研究了不同施钾肥处理对再生水灌溉番茄植株、果实以及根际土与非根际土Cd含量的影响。结果表明:再生水灌溉条件下,施钾肥处理可提高番茄果实产量,施加KCl较K2SO4增产效果明显,分别较不施肥处理可增产6.10%～24.00%和1.36%～13.16%;不施钾肥较不施肥处理番茄果实Cd含量降低,但降低幅度小于施加钾肥处理,施加KCl较K2SO4处理番茄果实Cd含量较低,Cd含量分别较不施钾肥处理分别减少58.33%和8.33%,且各处理均未超0.05mg/kg的限值标准;不施钾肥处理较不施肥处理土壤pH、Cd含量有所降低,降低幅度小于施钾肥处理,有效态Cd有所增加,施加KCl和K2SO4较不施肥处理有效态Cd降低,施加KCl和K2SO4较不施钾肥处理根际土和非根际土pH、Cd含量和有效态Cd含量均有所降低,其中施加KCl根际土和非根际土Cd含量分别降低2.96%～3.11%和5.75%～14.22%,施加K2SO4分别降低4.14%～5.90%和8.10%～8.29%;施加KCl根际土和非根际土有效态Cd含量分别降低10.75%～16.19%和13.98%～28.74%,施加K2SO4分别降低15.97%～20.55%和19.91%～24.70%。因此,再生水灌溉条件下,可通过选择施加适宜的钾肥种类,调控重金属Cd在土壤-作物系统的分布及其生物有效性,施加K2SO4较KCl相比,可一定程度降低土壤Cd全量及有效态Cd含量。

Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

Crop yield and water use efficiency （WUE） in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain （NCP）, A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system, Soil water depletion （~SWS） by crop generally decreased with the increase of irrigation and rainfall, while ASWS for the whole rotation was relatively stable among these irrigation treatments, High irrigations in wheat season increased initial soil moisture and ASWS for subsequent maize especially in the drought season, Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems, Grain yield decreased prior to evapotranspiraUon （ET） when ET reached about 300mm for wheat, while maize showed various WUEs with similar seasonal ET, For whole rotation, WUE declined when ET exceeded about 650 mm, These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP, Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.

Soil mineral nitrogen dynamics in fallow periods in a rainfed semiarid Mediterranean agricultural system

Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events.As an agronomic practice,fallow periods can be included even within the existing European Union common policy for crop diversification.This study aimed to quantify the effects of previous mineral fertilization on soil mineral nitrogen(N_(min))content and potential nitrate leaching during no-till fallow periods of crop rotation.The Leaching Estimation and Chemistry Model(LEACHM)was used for soil N_(min)prediction after fallow.During fallow periods,N_(min)measured in the soil profile increased by an average of 125 kg N ha^(-1),whereas the model showed an average increase of 95 kg N ha^(-1).The amount of nitrogen(N)leached was estimated to be 11–38 kg N ha^(-1).The N balance simulated using LEACHM might differ from the actual situation.The calibrated LEACHM underestimated soil N_(min)after a drought period followed by soil water replenishment,probably due to a pulse in soil C and N mineralization caused by the wetting of dry soil,but overestimated soil N_(min)after occasional rainy spells when soil quickly became saturated,probably due to occasional nitrous oxide emissions not being fully accounted for by the model and specific preferential water flow,which might lead to greater nitrate leaching than that simulated by LEACHM using the convection-dispersion equation.The results show that soil N_(min)measurements after fallow periods cannot be well predicted by LEACHM.The findings of this study provide a support for fertilization planning for crop rotation systems including a fallow period to avoid overfertilization in the following cropping season and reduce N environmental impacts.

Characteristics of water contamination in abandoned coal mines:a case study on Yudong River area,Kaili,Guizhou Province,China

The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017-2018 were analyzed.The effects of mine water drainage on the seasonality and physicochemical properties of the river water after mine closure were evaluated,and the feasibility of irrigation using river water and the degree of pollution to farmland were assessed using the Water Quality Standard for Farmland Irrigation.The results show that the mine water has low pH value(<3.5-4)and high levels of total hardness,SO_(4)^(2−),Fe,Al,and Zn.In addition,the pH of the mine water is negatively correlated with the presence of other metal ions.The correlation coefficient between the chemical oxygen demand(COD)and Fe reached 0.989.While the pollution levels of Pinglu and Baishui rivers were low,the confluence region of the two rivers was seriously polluted.However,only the levels of Fe and Cd slightly exceeded the Surface Water Environmental Quality Standard after the confluence of Yudong and Chongan rivers.Overall,the heavy pollution type of the confluent river is consistent with mine water pollution.The water quality is slightly better in the dry season compared than in the high-water period.Sulfate and Fe content decreased by 39 and 16 mg/L,respectively,and Cd content decreased two-fold.Despite these findings,this study shows that from 2017 to 2018,the pH and Cd content of the rivers at the confluence exceeded the irrigation limit and the water quality continued to deteriorate,which may pose a soil contamination risk.Long-term use of the river for irrigation water may cause toxic elements such as Cd,Fe,Mn,SO_(4)^(2−),Al,and F-to enter the food chain,thereby endangering the life and health of villagers in Yudong River area.

不同耕作方式和前茬作物对冬小麦水肥利用效率及产量影响

【目的】探讨不同耕作方式和前茬作物对冬小麦土壤养分、产量及水肥利用效率的影响。【方法】设置2个主处理:旋耕(RT)和免耕(NT),2个副处理:玉米前茬(MW)和大豆前茬(SW),共4个处理,分别记为RTMW、RTSW、NTMW、NTSW,研究不同耕作方式和前茬作物对冬小麦土壤养分、水肥利用效率及产量的影响。【结果】同一前茬作物下,免耕处理土壤含水率高于旋耕处理;同一耕作方式下,玉米前茬处理土壤含水率高于大豆前茬;冬小麦季各处理有机碳量、全氮量、速效磷量、速效钾量、铵态氮量、硝态氮量均随土层深度增加而降低。0~50 cm土层,NTSW处理均有利于冬小麦麦田土壤有机碳、全氮、硝态氮量的积累,较RTMW处理分别提高了4.14%~13.54%、35.51%~54.44%、55.75%~112%;10~50cm土层,RTMW处理后茬麦田速效磷、速效钾量较高;0~50 cm土层,RTSW处理后茬麦田铵态氮量最高,较RTMW处理高13.39%~20.64%;NTSW处理穗数、穗粒数、千粒质量显著高于其他处理,且冬小麦产量也高于其他处理,较RTMW处理增产16.62%;NTSW处理水分利用效率及氮磷钾利用效率均最高。【结论】NTSW处理有利于冬小麦田的养分积累,且水肥利用效率最高,增产效果较好。

生物质缓释土壤保水增肥剂对宁夏盐池县土壤及其作物的影响

为探讨生物质缓释土壤保水增肥剂对农田土壤水温环境、土壤养分吸收和作物产量的影响,在宁夏回族自治区吴忠市盐池县以玉米、马铃薯、燕麦等为供试作物,生物质缓释土壤保水增肥剂为供试材料,采用田间试验,设置生物质缓释土壤保水增肥剂不同梯度的施用量,测定土壤含水量、酸碱度、电导率、容重和土壤养分等,研究其对试验地区土壤理化性质、土壤养分以及不同作物产量的影响。结果表明:在施用量不同的情况下,所种植的作物总体上产量都有所增加。苏丹草和燕麦草增产率最高,分别达到36.26%和24.35%。荞麦在生物质缓释土壤保水增肥剂施用量为120kg/hm^(2)时产量增产率达到23.19%,而马铃薯在生物质缓释土壤保水增肥剂施用量为120kg/hm^(2)时产量增产率最高,达到了77.78%,增产效果显著。但玉米产量变化趋势有所不同,在生物质缓释土壤保水增肥剂施用量为60kg/hm^(2)时产量反而有所下降,当施用量增加至120kg/hm^(2)时产量有所上升,但增产率只有0.69%,主要是由于地块所处位置、地势以及土壤组分存在一定程度的差异性,导致生物质缓释土壤保水增肥剂施用量对玉米产量影响不大。

光学遥感在区域灌溉监测中应用的研究进展

农业干旱、灌溉用水效率低等问题严重制约着中国农业生产的发展.及时准确地获取田间水分信息是建立区域灌溉管理系统的前提和基础,传统的水分信息监测方法应用范围小、效率低,无法满足现代农业的需求,而遥感技术提供了一个相对高效精准的技术方法.分别介绍了作物需水量的计算方法和灌溉面积监测技术,其中作物需水量的计算介绍了土壤水分系数估算法和植被指数反演法,这2种方法都利用作物系数法对作物需水量进行计算,主要区别在于计算参数的获取方式;灌溉面积监测总结了基于光谱特征空间反演、冠层温度反演、蒸散发模型反演和植被指数反演4种方法,通过蒸散发模型和植被干旱指数反演灌溉面积是目前应用较为广泛的方法.在此基础上,构建基于田间水分信息的区域灌溉管理体系,以达到精准灌溉、科学决策的目的.

灌溉量和氮肥增效剂对夏玉米产量及水肥利用的影响

为探究水分和氮肥增效剂对夏玉米生长及水肥利用的综合影响,通过设置40 mm(W1)和60 mm(W2)两个灌水水平下不施氮肥(N0)、施用氮肥(U)、氮肥+硝化抑制剂(U+DCD)、氮肥+脲酶抑制剂(U+NBPT)、氮肥+双效抑制剂(U+N+D)5种氮肥施用措施,开展夏玉米田间试验。结果表明:相较于施用氮肥处理,氮肥配施增效剂可以显著提高夏玉米产量、成熟期地上生物量、净收益、水分利用效率和氮肥偏生产力,增幅分别为5.92%~13.82%、5.85%~18.07%、11.12%~24.30%、12.35%~41.83%和5.93%~13.80%,其中氮肥配施双效抑制剂效果较优;氮肥配施脲酶抑制剂和双效抑制剂可以降低夏玉米农田土壤氨挥发累积量和成熟期土壤硝态氮残留量,前者效果最优。相比于W1,W2水平下氮肥配施双效抑制剂处理玉米产量、成熟期地上生物量、净收益、水分利用效率和氮肥偏生产力分别提高10.54%、15.51%、19.40%、20.31%和27.36%;氮肥配施脲酶抑制剂处理农田土壤氨挥发累积量和硝态氮残留量分别降低11.33%和48.46%。综合考虑夏玉米施肥灌水方案的经济效益、环境效益、水肥利用效率和玉米植株生长,构建模糊综合评价体系,得到最优处理为灌水量60 mm下氮肥配施双效抑制剂。