Optimized NPK fertilizer recommendations based on topsoil available nutrient criteria for wheat in drylands of China

The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers.Critical nutrient values can be used for evaluating the nutritional status of a crop,and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential yield.Based on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China,we proposed a recommended fertilization method to determine nitrogen(N),phosphorus(P),and potassium(K)fertilizer input rates for wheat production,and then validated the method by a field experiment at 66 different sites in northern China.The results showed that wheat grain yield varied from 1.1 to 9.2 t ha^(-1),averaging 4.6 t ha^(-1),and it had a quadratic relationship with the topsoil(0-20 cm)nitrate N and soil available P contents at harvest.However,yield was not correlated with the inputs of N,P,and K fertilizers.Based on the relationship(exponential decay model)between 95–105%of the relative yield and topsoil nitrate N,available P,and available K contents at wheat harvest from 60 field experiments,the topsoil critical nutrient values were determined as 34.6,15.6,and 150 mg kg^(-1)for soil nitrate N,available P,and available K,respectively.Then,based on five groups of relative yield(>125%,115–125%,105–115%,95–105%,and<95%)and the model,the five groups of topsoil critical nutrient levels and fertilization coefficients(Fc)were determined.Finally,we proposed a new method for calculating the recommended fertilizer input rate as:Fr=Gy×Nr×Fc,where Fr is the recommended fertilizer(N/P/K)input rate;Gy is the potential grain yield;Nr is the N(N_(rN)),P(N_(rP)),and K(N_(rK))nutrient requirements for wheat to produce 1,000 kg of grain;and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c)fertilizer.A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5%(38.5 kg N ha^(-1))and P fertilizer input by 43.5%(57.5 kg P_(2)O_(5) ha^(-1))in northern China and did not reduce the wheat yield.This outcome can significantly increase the farmers’benefits(by 7.58%,or 139 US$ha^(-1)).Therefore,this new recommended fertilization method can be used as a tool to guide N,P,and K fertilizer application rates for dryland wheat production.

Effect of Tillage Methods and Foliar Fertilization (<i>Boost Extra</i>^TM) on Soil Physical Properties, Weed Dry Matter and Grain Yield of Sorghum in Ejiba, Kogi State, Nigeria

An experiment was carried out for two consecutive growing seasons (2012 and 2013) at the Research Site of the Lower Niger River Basin Development Authority, Ejiba, Nigeria, to examine the response of sorghum to tillage methods and foliar fertilizer (Boost ExtraTM) application. A split plot experiment was laid out in a Randomized Complete Block Design (RCBD) with three replicates to randomize the tillage methods (main plots) and foliar fertilizer application (sub-plots), respectively. The experiment comprised of three tillage methods: No Tillage (NT), Manual Tillage (MT) and convectional tillage (Ploughing, Harrowing and Ridging, PHR) and three foliar fertilizer rates: 0, 2 and 4 liters of foliar fertilizer per hectare. The parameters taken on soil physical properties and weed characters are soil moisture content (%), soil temperature (℃), weed species and weed dry weight (g). Growth and yield parameters taken are: average plant height (cm), stem girth (cm), leaf area (m2), days to 50% flowering, root dry weight (g), shoot dry weight (g), weight of 1000 seeds and grain yield per land area. Weeds were identified and harvested, and their dry weights were taken and recorded. Data were also collected from ten randomly selected plants in each plot. The data were statistically analyzed using GENSTAT. The analysis of variance (ANOVA) was carried out to find out the significance of variation among the treatments while the significant differences between mean treatments were separated using Duncan’s Multiple Range Test (DMRT) at 5% level of probability. The results obtained from this study indicated that tillage methods and foliar fertilizer application significantly affected growth and yield parameters of sorghum, consequently the yield per unit area. The results also indicated that “Manually Tilled” seedbed (MT) improved soil physical properties better than either plots with PHR or No Till plots in the study area. Foliar fertilizer application at 2 l/ha performed best in terms of growth and yield. It is therefore recommended that manual tillage should be used as a method of seedbed preparation for sorghum production. However, better and stable grain yield of sorghum could be obtained with the practice of manual tillage (MT) in combination with foliar fertilization at rate of 2 litres/ha. It is recommended that different tillage methods should be combined with foliar fertilizer application for higher grain yield in the study area.

Appropriate Location and Deployment Method for Successful Iron Fertilization

“High nutrient, low chlorophyll (HNLC)” regions were created by locking iron into sedimentary iron sulfides with hydrogen sulfide available from volcanic eruptions in surrounding oceans. Appropriate locations and deployment methods for the iron fertilization were far from volcanoes, earthquakes and boundaries of tectonic plates to reduce the chance of iron-locking by volcanic sulfur compounds. The appropriate locations for the large-scale iron fertilization are proposed as Shag Rocks in South Georgia and the Bransfield Strait in Drake Passage in the Southern Ocean due to their high momentum flux causing efficient iron deployment. The iron (Fe) replete compounds, consisting of natural clay, volcanic ash, agar, N2-fixing mucilaginous cyanobacteria, carbon black, biodegradable plastic foamed polylactic acid, fine wood chip, and iron-reducing marine bacterium, are deployed in the ocean to stay within a surface depth of 100 m for phytoplankton digestion. The deployment method of Fe-replete composite with a duration of at least several years for the successful iron fertilization, is configured to be on the streamline of the Antarctic Circumpolar Current (ACC). This will result in high momentum flux for its efficient dispersion on the ocean surface where diatom, copepods, krill and humpback whale stay together (~100 m). Humpback whales are proposed as a biomarker for the successful iron fertilization in large-scale since humpback whales feed on krill, which in turn feed on cockpods and diatoms. The successful large-scale iron fertilization may be indicated by the return of the humpback whales if they could not be found for a long period before the iron fertilization. On-line monitoring for the successful iron fertilization focuses on the simultaneous changes of the following two groups;the increase concentration group (chlorophyll, O2, Dissolved Oxygen (DO), Di Methyl Sulfide (DMS)) and the decrease concentration group (nitrate, phosphate, silicate, CO2, Dissolved CO2 (DCO2)). The monitoring of chlorophyll-a, nitrate phosphate, and silicate concentrations after deploying the Fe-replete complex is carried out throughout the day and night for the accurate measurement of algal blooms.

Study on the Rapid Method to Predict Longevity of Controlled Release Fertilizer Coated by Water Soluble Resin

The study discussed the rapid method to test and predict the longevity of controlled release fertilizers （CRFs） coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dissolving incubation and higher temperature leaching were used to study the patterns of the nutrient release of the CRFs. The correlation analysis between the days at 25℃ and the hours at 80℃ of Trincote 1 and Trincote 2 for the same cumulative release rates were conducted. Patterns of cumulative nutrient release curve followed one factor quadratic regression equation at each given temperatures, and each of relative coefficient was bigger than 0.995. As the temperature increased, nutrients release of the CRFs increased. The longevity of resin coated CRFs were predicted by use of both the cumulative nutrients release equation at 80℃ and the regression equation of release time needed for the same cumulative release rates between 25 and 80℃. There were only 0.3-6.9% relative errors between the tested longevity and predicted one. In conclusion, the longevity of resin coated CRFs could be predicted more quickly and precisely by use of the higher temperature short-term leaching method than that of the traditional differential release rate. The longevity of resin coated CRF could be rapidly and precisely predicted in a few hours by application of the higher temperature shortterm leaching method.

Leaching and Transformation of Nitrogen Fertilizers in Soil After Application of N with Irrigation: A Soil Column Method

A soil column method was used to compare the effect of drip fertigation (the application of fertilizer through drip irrigation systems, DFI) on the leaching loss and transformation of urea-N in soil with that of surface fertilization combined with flood irrigation (SFI), and to study the leaching loss and transformation of three kinds of nitrogen fertilizers (nitrate fertilizer, ammonium fertilizer, and urea fertilizer) in two contrasting soils after the fertigation. In comparison to SFI, DFI decreased leaching loss of urea-N from the soil and increased the mineral N (NH4+-N + NO3- -N) in the soil. The N leached from a clay loam soil ranged from 5.7% to 9.6% of the total N added as fertilizer, whereas for a sandy loam soil they ranged between 16.2% and 30.4%. Leaching losses of mineral N were higher when nitrate fertilizer was used compared to urea or ammonium fertilizer. Compared to the control (without urea addition), on the first day when soils were fertigated with urea, there were increases in NH4+-N in the soils. This confirmed the rapid hydrolysis of urea in soil during fertigation. NH4+-N in soils reached a peak about 5 days after fertigation, and due to nitrification it began to decrease at day 10. After applying NH4+-N fertilizer and urea and during the incubation period, the mineral nitrogen in the soil decreased. This may be related to the occurrence of NH4+-N fixation or volatilization in the soil during the fertigation process.

Response of Tomato Plants to a New Application Method of Polyolefin-Coated Fertilizer

The response of tomato (Lycopersicon esculentum) plants basically fertilized with 0.3 g N per plant of compound fertilizer with a N:P2O5:K2O ratio of 20:10:20 to sticks of polyolefin-coated fertilizer (POCF) (Long70 with a N:P2O5:K2O ratio of 14:12:14) applied 23 d after transplanting was investigated using rooting boxes in the greenhouse. The results at 26 and 40 d after stick fertilizer treatment showed that the use of the stick fertilizer greatly increased the production of many new fine roots from the tomato plants. Compared to the unfertilized control, root length and root length density in the stick fertilizer treatment increased by 3.6-6.7 fold. In the soil zones near the stick fertilizer, root weight and root mass density were also significantly higher for the stick fertilizer treatment. Additionally, the use of the stick fertilizer increased the N, P and K concentrations in the leaves and stems of the tomato plants. The new fine roots growing near the stick fertilizer not only absorbed more nutrients and translocated them to the shoots, but also contained more nutrients within themselves. The soil ammonium and nitrate N data showed that N released from the stick fertilizer played a major role in inducing the production of new fine roots. These results indicated that stick fertilizer could be used as an alternative to the co-situs application technique to change and control the root distribution of crops as well as to increase the potential capacity of roots for water and nutrient absorption.

Terminal fertility control: Clients’ own reason for the choice of the contraceptive method

Background: The prevalence of contraceptive use has increased worldwide due to the development and introduction of modern contraceptives and the establishment of organized family planning programs. In Nigeria, there is a very slow rise in contraceptive use prevalence, resulting in high fertility rate. Generally contraceptive is either used for birth spacing, or for the purpose of terminal fertility control to limit the number of children, and the choice of method for this purpose varies. Aims and Objectives: To determine the contraceptive methods of choice among clients seeking terminal fertility control, and their reasons for the choice of such methods. Materials and Methods: A cross-sectional study of clients attending the family planning clinic of Ladoke Akintola University of Technology Teaching hospital over a period of twenty-four months, between July, 2009 and June, 2011. All clients who had completed their family, and wanted a contraceptive method to limit their family size filled the semi-structured questionnaire after giving their informed consent. Clients’ own reasons for the choice of the particular contraceptive method were grouped, entered into SPSS work sheet, and analyzed using SPSS version 17. Result: There were five hundred and ninety-two new contraceptive method acceptors during the study period, of which 264 (44.6%) were for terminal fertility control. Progestogen-only injectable contraceptive was the method of choice for terminal fertility control by 145 (54.9%) of the clients, while 85 (32.2%) made intrauterine contraceptive device (copper-T) their method of choice, and the least chosen method was female surgical sterilization (2, 0.8%). Ease of administration, satisfaction with previous use, long duration of action, and husband’s preference were the reasons for the choice of the methods. Conclusion: There is awareness of terminal fertility control in Nigeria, especially in the southwestern region of the country, and this may be responsible for the decreasing prevalence of grandmultiparity in the region. However, reversible contraceptive method is the preferred option for this purpose.

温度和孵化方式对大鳍鳠受精卵孵化效果的影响

为探究大鳍鳠(Mystus macropterus)受精卵的最适孵化温度及孵化方式,采用单因子设计实验研究了不同温度(22、24、26、28和30℃)、不同孵化方式(脱黏孵化(蛋白酶脱黏、滑石粉脱黏)、挂网孵化、孵化框孵化)对大鳍鳠受精卵孵化效果的影响。结果表明:大鳍鳠仔鱼出膜率随孵化温度的升高呈先升高后降低的趋势,分别为22℃组(0)<30℃组(12.51%)<24℃组(17.95%)<26℃组(25.40%)<28℃组(30.51%),不同温度组差异显著,二项式拟合得到最适孵化温度为26.8℃;出膜后24 h成活率表现为24℃组(54.76%)显著低于26℃组(95.45%)、28℃组(91.67%)和30℃组(92.59%),后三者之间差异不显著;96 h成活率分别为52.38%、90.91%、92.59%和40.74%,表明低温(24℃)和高温(30℃)都显著影响成活率。仔鱼出膜时间随温度的上升而逐渐缩短,范围为46~88 h。4种孵化方式的24 h好卵率结果表明挂网组(48.11%)>孵化框组(45.05%)>蛋白酶脱黏组(19.98%)>滑石粉脱黏组(15.32%),四个实验组之间差异显著。出膜率表现为挂网组(16.07%)>蛋白酶脱黏组(12.08%)>孵化框组(9.61%)>滑石粉脱黏组(9.26%)。出膜率/24 h好卵率显示脱黏组的值最大(均为60.46%),显著高于挂网组(33.40%)和孵化框组(21.32%)。在实验设置的3个蛋白酶脱黏浓度梯度下,24 h和48 h好卵率均表现为0.75 g/L组显著高于3 g/L组和1.5 g/L组,后两者之间差异不显著,出膜率则表现为随浓度降低而显著降低的趋势,说明卵膜对受精卵起到较好的保护作用,同时对出膜过程造成困难,导致出膜率降低。可见,温度和孵化方式均对大鳍鳠受精卵孵化有显著影响,大鳍鳠的最适孵化温度为26.8℃,孵化方式优先选择蛋白酶脱黏孵化,浓度为3 g/L。

施肥方式和减施氮肥对寒地水稻抗倒性的影响

为明确施肥方式和减施氮肥的主效及互作效应对寒地水稻产量及抗倒性的影响,以水稻‘垦粳8’为材料,比较不同施肥方式和减施氮肥对寒地水稻产量、株高、以及各节间长度、直径、鲜重、茎壁厚度及抗折力的影响差异。结果表明:侧深施肥产量、第三节间长度、重心高度分别显著或极显著高于全层施肥7.49%、7.02%、2.54%。侧深施肥第一节间直径、茎壁厚度、鲜重、抗折力分别显著或极显著低于全层施肥7.85%、14.18%、4.13%、2.03%;第二节间直径、茎壁厚度、抗折力分别显著或极显著低于全层施肥8.15%、9.18%、18.61%;第三节间茎壁厚度和抗折力分别极显著低于全层施肥16.00%、16.15%。侧深施肥的抗倒伏指数极显著低于全层施肥16.60%。减施氮肥条件下重心高度、各节间长度、茎壁厚度、节间鲜重及节间抗折力变化多利于提高水稻抗倒性,减氮15%和减氮30%处理的抗倒伏指数较常规施氮分别极显著提高6.19%和9.52%。全层施肥条件下抗倒伏指数随施氮量下降呈增加趋势,而侧深施肥的减氮施肥水平间差异不显著。

控释肥颗粒群仿真接触参数标定与试验

接触参数影响控释肥颗粒离散元仿真结果。为了精准模拟控释肥颗粒力学行为与运动规律,本文基于离散元法对控释肥颗粒的接触参数进行标定与试验。首先,建立控释肥离散元基础模型,并利用台架和仿真试验相结合的方法,在EDEM中对控释肥颗粒与PVC板之间接触参数进行标定。其次,通过碰撞弹跳试验、斜面滑移试验和斜面滚动试验测得控释肥颗粒与PVC板之间的碰撞恢复系数、静摩擦因数和滚动摩擦因数分别为0.539、0.507和0.105。最后,通过堆积试验、最陡爬坡试验和正交旋转组合试验,得到控释肥颗粒间的碰撞恢复系数、静摩擦因数和滚动摩擦因数分别为0.38、0.25和0.09,并通过无底圆筒提升试验和排肥台架试验进行验证。试验结果表明,堆积角实际值与仿真结果的相对误差为1.54%,排肥量实际值与仿真结果4种转速下的相对误差分别为4.38%、4.23%、4.41%、4.36%,所标定的控释肥接触参数精准有效,可为控释肥离散元仿真提供数据和模型支撑。

电感耦合等离子发射光谱法与钒钼黄比色法在有效磷含量测定中的应用比较

在农业生产过程中需要对土壤中的有效磷含量以及肥料中的有效磷含量进行检测,为配方施肥提供重要依据,有效磷检测方法的准确性是评判肥料质量高低、实现配方施肥的关键。研究对电感耦合等离子发射光谱法与钒钼黄比色法这两种有效磷检测方法的灵敏度和准确度进行了比较,明确了电感耦合等离子发射光谱法在213.6 nm条件下的磷检出限为0.05 mg/L,钒钼黄比色法在400 nm检测波长的灵敏度最高,检出限为0.32 mg/L。对两种检测方法的检测准确度进行比较,结果表明电感耦合等离子发射光谱法对不同浓度的有效磷检测准确度均高于96%,其准确度受磷浓度的影响小;传统的钒钼黄比色法检测准确度受磷浓度、检测波长影响较大,对磷含量低于5 mg/L的样品检测准确度下降,且低于电感耦合等离子发射光谱法的检测准确度。研究结果认为对于未知浓度范围的样品,钒钼黄比色法在400 nm波长检测条件下的检测结果较为理想。

不同肥料配比对糜子产量和品质的调控效应

为探明不同施肥方式对糜子营养品质、食味品质和产量的影响,于2019年在山西河曲进行试验,以河曲大红糜子为材料,选用不同配比的有机肥(羊粪)、生物菌肥、尿素和复合肥,研究不同施肥配比对糜子品质和产量的影响。结果表明:不同肥料配比对糜子产量和品质性状显著影响,复合肥和有机肥(F+Y)配施显著提高糜子籽粒产量(GY)、净光合速率(Pn)、钙(Ca)和铁(Fe)含量,显著减低直链淀粉含量(AC);相关性分析发现,籽粒产量(GY)和净光合速率(Pn)呈极显著正相关,相关系数为0.82,镁(Mg)与铁(Fe)呈极显著正相关,值为0.68,直链淀粉含量(AC)与醇溶蛋白含量(Gli)、钙(Ca)达到极显著负相关,值分别为-0.66和-0.50;主成分分析发现,糜子各性状指标分为4个主成分,分别代表糜子食味品质、营养品质、产量指标和蛋白营养品质,综合得分以复合肥和有机肥(F+Y)处理最高,并显著高于其他处理。综上所述,复合肥(187.5 kg·hm^(-2))与有机肥(1.5×10^(4)kg·hm^(-2))配施是糜子获得优质高产的主要施肥方式。

养殖尾水混合不同比例水溶肥种植水培生菜的综合效益评价

以“奶油生菜”为研究对象,将不同量的山崎配方水溶肥溶于工厂化养鱼尾水,配制成混合营养液,进行营养液膜栽培(NFT)水培生菜实验,以期筛选出最佳水肥配比,为实现工厂化养鱼尾水资源化利用提供理论依据。实验设置5个处理,分别为S1(123g水溶肥+150L养鱼尾水)、S2(98.4g水溶肥+150L养鱼尾水)、S3(73.8g水溶肥+150L养鱼尾水)、S4(49.2g水溶肥+150L养鱼尾水)、S5(24.6g水溶肥+150L养鱼尾水),以CK(123g水溶肥+150L清水)作为对照,探究不同处理对生菜产量和品质的影响。采用基于熵权法的TOPSIS综合效益评价模型分析确定最佳水肥配比参数。结果表明,混合营养液能提高生菜对水肥的吸收量,但随水溶肥浓度增加,生菜耗肥量呈先增大后减小的趋势;不同处理下生菜耗水耗肥量均低于CK处理,S1-S5处理相比CK处理分别节肥25.01%、19.15%、34.12%、51.89%和74.10%。混合营养液能有效促进生菜生长,但生菜各项生长指标均随水溶肥浓度上升呈先增大后减少的趋势,S2处理下生菜产量最高,为1.88kg·m^(-2),相比CK处理增加15.32%。此外,混合营养液可提高生菜品质,可溶性糖和可溶性蛋白含量呈先增大后减小的趋势,S2处理下生菜可溶性糖和可溶性蛋白含量最高;维生素C(VC)含量、硝酸盐含量均与水溶肥浓度呈正相关,S1处理下VC含量最高,S1-S5处理下硝酸盐含量均低于CK处理。综合效益评价结果表明,S2处理对生菜的生长最为有利,可以获得较高的产量并兼具较好的品质,为最佳配比,养鱼尾水与水溶肥合理配施后,可显著促进水肥吸收,提高生菜产量和品质,实现作物生产效益最佳。

锌肥施用方式对苹果光合特性、品质及经济效益的影响

【目的】探究不同锌肥施用方式对土壤有效锌含量、苹果树叶片和果实锌含量、以及苹果光合特性、品质及经济效益的影响,以期为苹果合理施用锌肥提供参考。【方法】在陕西省蒲城县和乾县以“长富二号”苹果为试材,采用大田试验,设置不施锌(对照,T1)、叶面喷施锌肥(T2)和水肥一体化追施锌肥(T3)3个处理,测定不同处理土壤有效锌含量、苹果果实和叶片锌含量、叶片生物学性状以及苹果产量、品质和经济效益。【结果】在乾县和蒲城,在0~20和20~40 cm土层,T2和T3处理土壤有效锌含量均高于T1处理,且T3处理土壤有效锌含量最高,分别为1.88,1.22 mg/kg(0~20 cm土层)和1.16,0.70 mg/kg(20~40 cm土层)。在乾县,T2处理叶片和果实锌含量最高,其次为T3处理,T1处理最低;在蒲城,T2和T3处理叶片、果实锌含量均显著高于T1处理,其中T3处理均最高。在乾县和蒲城,与T1处理相比,T2和T3处理百叶厚和百叶质量及叶绿素含量总体上均显著增加。在乾县,苹果的果形指数为0.83~0.89,其中T1处理明显高于T2和T3处理;在蒲城,苹果的果形指数为0.81~0.91,其中T3处理明显高于T1和T2处理。在蒲城,3个处理的可溶性固形物和可滴定酸含量均无显著差异;在乾县,T2和T3处理可滴定酸含量显著高于T1处理,可溶性固形物含量3个处理间无显著差异。在乾县和蒲城,T2和T3处理可溶性糖和V C含量均显著高于T1处理。乾县T2处理苹果产量和净利润均最高,分别为30961 kg/hm^(2)和82505元/hm^(2),较T1处理分别增加了45.49%和52.85%;蒲城T3处理苹果产量和净利润均最高,分别为29159 kg/hm^(2)和78595元/hm^(2),较T1处理分别提高了28.56%和65.77%。【结论】施用锌肥有利于提高土壤、苹果叶片和果实锌含量以及苹果产量和品质;从产量和经济效益的角度出发,水肥一体化追施锌肥的效果比叶面喷施锌肥更稳定。

氮肥运筹与硅锌肥配施对虾稻1号产量和品质的影响

为探讨优质食味籼稻虾稻1号产量和品质协同提升栽培技术,在施氮量180 kg/hm^(2)水平下,研究3种基肥∶分蘖肥∶穗肥运筹比例(7∶3∶0、5∶3∶2和3∶3∶4,分别记作N_(7+3+0)、N_(5+3+2)和N_(3+3+4))并配施硅锌肥处理对虾稻1号产量和品质的影响。结果表明,不同处理下虾稻1号产量整体表现为N_(7+3+0)<N_(5+3+2)≈N_(3+3+4)。提高氮肥在穗肥中的比例,虾稻1号糙米率、精米率和整精米率呈先增加后降低趋势,而胶稠度和蛋白质含量呈上升趋势。其中,氮肥运筹对整精米率的影响达到显著水平,对蛋白质含量的影响达到极显著水平。相同氮肥运筹方式下,配施硅肥或硅锌肥均表现出一定的增产效应,但对稻米品质指标的影响均未达到显著水平。综上所述,N_(5+3+2)运筹方式可实现虾稻1号产量与品质的协同提升,而配施硅锌肥有助于其产量进一步提升。

连续化肥减量配施有机肥提升植烟土壤肥力质量的综合评价

为准确评价连续多年化肥减量配施有机肥料对烤烟产量及植烟土壤综合肥力质量的影响,探究植烟土壤质量提升与烤烟绿色优质协同的化肥减量有机替代技术。以长期定位试验的第7年数据为基础,运用因子分析法、相关系数法、内梅罗指数法,对不施肥(CK)、当地推荐常规施肥(100%化肥,CF)、化肥减量20%配施有机肥(OF)和配施生物有机肥(BIO)4个处理的土壤肥力质量进行综合评价,并采用随机森林回归分析,探讨各土壤单项肥力指标对烤烟产量的解释度。结果表明,在连续7年化肥减量20%条件下,配施有机肥和生物有机肥均能降低烤烟青枯病和黑胫病的发病率和病情指数,提高烤烟经济性状、产量可持续性与稳定性,提高植烟土壤养分含量和土壤肥力综合质量。随机森林分析表明,植烟土壤有效磷、碱解氮、全氮是影响烤烟产量的决定因素,其解释率分别为19.66%、15.38%、12.07%。在3种评价方法下,植烟土壤综合肥力指数IFI值均表现为BIO>OF>CF>CK,BIO和OF处理较CF处理分别提高23.03%~31.75%和4.92%~7.94%。3种评价方法的IFI值与烤烟相对产量均呈显著或极显著正相关关系,相关系数大小依次为内梅罗指数法(0.884)>因子分析法(0.867)>相关系数法(0.747)。因此,连续多年化肥减量配施不同有机肥具有提高植烟土壤综合肥力质量和烤烟产量及质量的持续效应,且以化肥减量20%配施生物有机肥的效果最优。

基于“3414”试验的切花芍药氮磷钾推荐施肥量研究

针对切花芍药生长过程中盲目施肥的现状,以二年生芍药‘向天歌’为研究对象,采用“3414”试验施肥方案,结合隶属函数法,研究氮、磷、钾肥不同用量对切花芍药生长的影响,探讨切花芍药生产适宜的肥料用量。结果表明:不同施肥处理对芍药株高、茎粗、蕾径、分株数和切花数影响显著(P<0.05);氮、磷缺素区的综合隶属函数值小于无肥区,缺钾区大于无肥区,对芍药生长的影响为氮>磷>钾;N2P2K1处理的综合隶属函数值最大,为0.61,芍药植株生长最好;对各处理的综合隶属函数值和施肥量进行肥料效应函数拟合分析,一元二次、二元二次肥料效应函数方程拟合相关性均达显著水平,三元二次肥料效应方程为非典型模型,采用频率分析法计算肥料推荐量。综合分析各肥料效应函数方程的推荐用量及相应的综合隶属函数值,本试验切花芍药推荐施肥量为N 212.7 kg/hm^(2)、P_(2)O_(5)46.2 kg/hm^(2)、K_(2)O 49.9 kg/hm^(2),施肥配比为1∶0.21∶0.23,可用于本试验区切花芍药生产的施肥参考。

基于宏基因组测序揭示不同施肥方式对茶园土壤微生物群落的季节性影响

为揭示不同施肥方式对茶园土壤微生物群落的季节性影响,采用宏基因组测序,比较分析了同一茶园习惯施肥(CF)、微生物有机肥配施控释复合肥(MC),在冬季至夏季3个时间点[11月14日(CF1、MC1)、3月1日(CF2、MC2)、5月15日(CF3、MC3)]的土壤微生物群落组成和结构。结果表明,共获得311211956条高质量测序数据和1763759个Unigenes。主成分和相关性分析表明,MC1和CF1的土壤微生物基因丰度聚为一类,其他独聚一类。不同季节,CF和MC的细菌、古菌、真菌分别占微生物总数的88%~89%、0.8%~2.0%、0.02%~0.10%;古菌数量逐渐增加,真菌数量先增加后降低。CF2、CF3的古菌数量分别高于MC2、MC3,而真菌数量相反;CF2、CF3的细菌、真菌丰度分别显著低于MC2、MC3,古菌丰度相反。MC1、MC2、MC3之间的细菌、古菌、真菌丰度存在显著差异,而CF1与CF3的真菌丰度接近。相较于CF,MC提高了土壤细菌中的变形菌门、放线菌门、芽单胞菌门、绿弯菌门、拟杆菌门、硝化螺旋菌门、装甲菌门相对丰度,降低了酸杆菌门、疣微菌门、浮霉菌门相对丰度;提高了古菌中的奇古菌门相对丰度,降低了广古菌门、泉古菌门、深古菌门相对丰度;提高了真菌中的毛霉门、捕虫霉门、隐真菌门相对丰度,降低了担子菌门相对丰度。总体上,CF和MC优势细菌门、优势古菌门、优势真菌门相对丰度的季节性变化趋势存在一定差异。茶园土壤微生物群落组成和结构呈现一定的季节性、施肥方式性变化规律;微生物有机肥配施控释复合肥可以提高土壤细菌丰度、真菌数量和丰度,降低古菌数量和丰度,改变土壤优势菌群的组成,为充分利用微生物资源、提高茶树养分利用率等提供了理论依据。

甘肃高寒阴湿区播种方式和氮肥施用量对猫尾草种质生产性能的影响

采用裂区试验设计,通过研究甘肃高寒阴湿区4个氮肥施用量(A1:施纯氮量0 kg/hm^(2),A2:施纯氮量90 kg/hm^(2),A3:施纯氮量180 kg/hm^(2),A4:施纯氮量360 kg/hm^(2))和3种播种方式(B1:条播,B2:撒播,B3:点播)对4个猫尾草种质(C1:新品系,C2:‘川西’,C3:‘岷山’,C4:‘克劳沃1号’)生产性能的影响,以筛选出最佳氮肥施用量、最佳播种方式和最佳猫尾草种质。结果表明,从单因素看,4个氮肥施用量间,A4的平均生产性能最好;3种播种方式间,B3的平均生产性能最好;4个猫尾草种质中,C1的平均生产性能最好。从二因素交互作用看,氮肥施用量×猫尾草种质交互作用间,A4C3的平均生产性能最好;播种方式×猫尾草种质交互作用间,B3C1的平均生产性能最好;氮肥施用量×播种方式交互作用间,A4B3的平均生产性能最好。从三因素交互作用看,C1在A2B3处理下生产性能最好;C2和C4在A4B3处理下生产性能最好;C3在A4B2处理下生产性能最好。综上,新品系的最佳氮肥施用量为90 kg/hm^(2),最佳播种方式为点播;‘川西’和‘克劳沃1号’的最佳氮肥施用量为360 kg/hm^(2),最佳播种方式为点播;‘岷山’的最佳氮肥施用量为360 kg/hm^(2),最佳播种方式为撒播。

基于长期氮肥示踪试验评估氮肥利用率算法的合理性

氮肥利用率是衡量氮肥被作物利用的一个指标,常规采用的计算方法为差减法和15N示踪法,主要是通过作物吸收的氮量来计算氮肥利用率。由于这两种方法没有考虑氮肥在土壤中的残留和后效,显著低估了施用氮肥的实际效应。为此,国内外研究者一直在探索更实际的氮肥利用率计算法。不同的改进方法以不同的表现形式包含了氮肥的遗留效应,弥补了差减法和15N示踪法在短期试验中对实际氮肥利用率的严重低估,基本接近于实际氮肥利用率,但远高于常规差减法或15N示踪法估算值。在本文中定义的实际氮肥利用率(ANUE)为:在土壤残留示踪氮被完全消耗的条件下,作物地上部吸收肥料氮占施氮量的百分比。法国28年旱地作物的氮肥叠加利用率为61.3%~65.3%,中国太湖地区17年的水旱轮作体系示踪氮肥试验中氮肥叠加利用率为38.6%~43.0%。本研究采用Origin 2021的图形数字化工具,获取这两个长期定位试验数据,包括每季作物吸收15N、土壤残留15N数据,分别以耗竭耕层(0—20 cm)、1 m、2 m土体中的氮素残留量来计算氮肥利用率。以此为参照标准,评估土壤氮素平衡法和氮肥有效率法计算结果的合理性。基于2 m土体残留肥料氮的土壤氮素平衡法和氮肥有效率法,会高估旱地作物的氮肥利用率;而以耕层土壤残留肥料氮作为估计参数时,则与旱地实际氮肥利用率基本一致(61%~74%);而氮肥有效率(41%~52%)可以很好地估算我国太湖地区水旱轮作体系的实际氮肥利用率。因此,跨地块或作物系统的氮肥利用率比较,应选择适当的计算方法,以避免由不同方法导致的不可比性而产生误解。氮肥有效率法(将作物吸收和土壤残留氮均视为有效部分)可以通过短期试验获得接近实际的氮肥利用率,具有广泛的应用价值。