Natural Radioactivity and Dose Assessment for Brands of Chemical and Organic Fertilizers Used in Saudi Arabia

The activity concentration of naturally occurring radionuclides 40K, 226Ra and 232Th have been measured in different brands of fertilizer samples in Saudi Arabia using sodium iodide gamma spectrometry. The results of measurements showed that the mean (ranges) of specific activities for 226Ra, 232Th and 40K activities in the nitrogen, phosphorus and potassium fertilizers are 64 (35.8 - 120.7), 17 (3.2 - 56.8) and 2453 (744.9 - 4227.1) Bq/kg, respectively. With respect to organic fertilizers under investigation, the average radioactivity of 226Ra, 232Th and 40K are 42, 10 and 333 BqKg?1, respectively. Radium equivalent activity is not exceed 370 Bq/kg, the maximum permissible limit for radiation dose for all present samples. Average values of the three natural radionuclides measured in the brands of fertilizers used in Saudi Arabia are within the range of values reported in several other countries. This study could be useful as baseline data for radiation exposure to fertilizers and their impact on human health.

Combined application of organic fertilizer and chemical fertilizer alleviates the kernel position effect in summer maize by promoting post-silking nitrogen uptake and dry matter accumulation

Adjusting agronomic measures to alleviate the kernel position effect in maize is important for ensuring high yields.In order to clarify whether the combined application of organic fertilizer and chemical fertilizer(CAOFCF)can alleviate the kernel position effect of summer maize,field experiments were conducted during the 2019 and 2020 growing seasons,and five treatments were assessed:CF,100%chemical fertilizer;OFCF1,15%organic fertilizer+85%chemical fertilizer;OFCF2,30%organic fertilizer+70%chemical fertilizer;OFCF3,45%organic fertilizer+55%chemical fertilizer;and OFCF4,60%organic fertilizer+40%chemical fertilizer.Compared with the CF treatment,the OFCF1 and OFCF2 treatments significantly alleviated the kernel position effect by increasing the weight ratio of inferior kernels to superior kernels and reducing the weight gap between the superior and inferior kernels.These effects were largely due to the improved filling and starch accumulation of inferior kernels.However,there were no obvious differences in the kernel position effect among plants treated with CF,OFCF3,or OFCF4 in most cases.Leaf area indexes,post-silking photosynthetic rates,and net assimilation rates were higher in plants treated with OFCF1 or OFCF2 than in those treated with CF,reflecting an enhanced photosynthetic capacity and improved postsilking dry matter accumulation(DMA)in the plants treated with OFCF1 or OFCF2.Compared with the CF treatment,the OFCF1 and OFCF2 treatments increased post-silking N uptake by 66.3 and 75.5%,respectively,which was the major factor driving post-silking photosynthetic capacity and DMA.Moreover,the increases in root DMA and zeatin riboside content observed following the OFCF1 and OFCF2 treatments resulted in reduced root senescence,which is associated with an increased post-silking N uptake.Analyses showed that post-silking N uptake,DMA,and grain yield in summer maize were negatively correlated with the kernel position effect.In conclusion,the combined application of 15-30%organic fertilizer and 70-85%chemical fertilizer alleviated the kernel position effect in summer maize by improving post-silking N uptake and DMA.These results provide new insights into how CAOFCF can be used to improve maize productivity.

Yield, Growth and Vegetative Development Parameters Response of Dry Beans to Organic and Inorganic Fertilizers and Biofertilizer

As part of the promotion of common bean cultivation, fertilization methods will have to be proposed to growers. The aim of this study is therefore to develop a technical itinerary for dry bean fertilization. To this end, different types of chemical and organic fertilizers were evaluated on three dry bean varieties (HARI25/GHA19, HARI35/GHA19 and HARI36/GUI21). Seven (7) doses of chemical and organic fertilizers were used, including two controls (D0 with no fertilizer and D1, the reference dose using NPK base and cover fertilizers in the form of urea). The fertilization trial was set up as a Split-Plot design, with variety as the primary factor and dose as the secondary factor. The experiment was repeated three (3) times. The results showed that vegetative development parameters and fruit set rate varied according to the variety studied. For yield and its components, the treatments had a significant effect. Indeed, the response of varieties to fertilizers was specific. For each variety used, the optimum yield was obtained with a different treatment, thus highlighting the genotype effect of the dry bean varieties studied. Among the treatments tested, D4 (5 t organic fertilizer/ha) performed best in all three varieties, generating yield increases of 20%, 46% and 91% respectively.

Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan of Southern China

To evaluate the effect of organic manure application with chemical fertilizers on rice yield and soil fertility under long-term double-rice cropping system, a six year field experiment was conducted continually in the paddy soil derived from Quaternary red clay in Hunan Province of southern China. Four different treatments, i.e., no nitrogen with chemical P and K （PK）, swine manure only （M）, N, P and K chemical fertilizers only （NPK）, and half chemical fertilizers combined with half swine manure （NPKM） with four replications were included. Each N, P and K application rate was the same at all the treatments （except the N application rate at PK） and N application rate was 150 kg N ha^-1. All fertilizers were applied to soil tillage layer with once application as baseal fertilizers. The nutrients uptake rate, grain yield, nitrogen use efficiency, and soil organic matter content at each treatment were investigated. The NPKM treatment achieved the highest mean annual yield of 12.2 t ha^-1 （68% higher than that of PK）. Higher dry matter accumulation and nutrients absorption were observed during the middle-late growth period in the NPKM treatment, with higher panicle number per unit and filled-grain number per panicle. Its average nitrogen use efficiency was 36.3% and soil organic matter increased by 18.5% during the experimental period in the NPKM treatment, which were significantly higher than those in the NPK treatment. Organic manure application with chemical fertilizers increased the yield and nitrogen use efficiency of rice, reduced the risk of environmental pollution and improved soil fertility greatly. It could be a good practical technique that protects the environment and raises the rice yield in this region.

Residual Effect of Long Term Application of Organic and Mineral Fertilizers on Selected Chemical Properties of a Savanna Alfisol

The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was left fallow for fourteen years due to lack of funds. Topsoil was collected from plots that received three levels of cow dung （D）, nitrogen （N） and phosphorus （P） in all possible combinations. The soils were analyzed for selected chemical properties. Except for significant effect of applied P on available P, sole application of cow dung, N or P had no significant effect on all the measured soil properties. The interaction of D and P significantly affected the mean values of exchangeable Ca, Mg, K and ECEC in the range of 1.12-1.96, 0.62-1.11, 0.37-0.64 and 2.82-4.11 cmol/kg respectively. The most important results were the ability of the plot that received neither D nor P to significantly increase these parameters than the plots that received only one of the treatments. The results show that the fallow period has changed the effects of application of organic and mineral fertilizers on the soil chemical properties under continuous cultivation by modifying them towards those of a native savanna Alfisol.

Carbon sequestration rate,nitrogen use efficiency and rice yield responses to long-term substitution of chemical fertilizer by organic manure in a rice–rice cropping system

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield,soil carbon storage,and nutrient use efficiency.However,how the long-term substitution of chemical fertilizer with organic manure affects rice yield,carbon sequestration rate(CSR),and nitrogen use efficiency(NUE)while ensuring environmental safety remains unclear.This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield,CSR,and NUE.It also determined the optimum substitution ratio in the acidic soil of southern China.The treatments were:(i)NPK0,unfertilized control;(ii)NPK1,100%chemical nitrogen,phosphorus,and potassium fertilizer;(iii)NPKM1,70%chemical NPK fertilizer and 30%organic manure;(iv)NPKM2,50%chemical NPK fertilizer and 50%organic manure;and(v)NPKM3,30%chemical NPK fertilizer and 70%organic manure.Milk vetch and pig manure were sources of manure for early and late rice seasons,respectively.The result showed that SOC content was higher in NPKM1,NPKM2,and NPKM3 treatments than in NPK0 and NPK1 treatments.The carbon sequestration rate increased by 140,160,and 280%under NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK1 treatment.Grain yield was 86.1,93.1,93.6,and 96.5%higher under NPK1,NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK0 treatment.The NUE in NPKM1,NPKM2,and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons.Redundancy analysis revealed close positive relationships of CSR with C input,total N,soil C:N ratio,catalase,and humic acids,whereas NUE was closely related to grain yield,grain N content,and phenol oxidase.Furthermore,CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.The technique for order of preference by similarity to ideal solution(TOPSIS)showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE.Therefore,substituting 70%of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

Mitigation of N_(2)O emissions in water-saving paddy fields:Evaluating organic fertilizer substitution and microbial mechanisms

Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.

Effects of Biological Organic Fertilizer on Flue-cured Tobacco Chemical Composition

Through field experiment,special biological fertilizer and cake fertilizer were applied collectively to tobacco,and chemical compositions of Wanxi flue-cured tobacco leaves were researched.The results showed that the increase of biological organic fertilizer would significantly improve soil nutrient supplying capacity.Compared with conventional fertilization,the contents of reducing sugar,total sugar and starch in different parts of tobaccos which were applied with biological organic fertilizer were closer to standards of excellent tobacco.In the treatment,the ratio of reducing sugar and nicotine in tobacco was more suitable in middle and lower parts of the plant and the contents of total N,nicotine and chlorine in tobacco were lowered,improving tobacco quality.

Impacts of chemical fertilizer reduction and organic amendments supplementation on soil nutrient,enzyme activity and heavy metal content

Excessive use of agro-chemicals （such as mineral fertilizers） poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments： 100% chemical fertilizer （CF100）, 80% chemical fertilizer （CF80）, 60% chemical fertilizer and 20% organic fertilizer （CF60＋OM20）, and 40% chemical fertilizer and 40% organic fertilizer （CF40＋OM40）. Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction （CF80） had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer （CF60＋OM20, CF40＋OM40） significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.

Effect of Long-Term Fertilization on Organic Nitrogen Forms in a Calcareous Alluvial Soil on the North China Plain

In order to illustrate the change of nitrogen （N） supply capacity after long-term application of manure and chemical fertilizer, as well as to properly manage soil fertility through fertilizer application under the soil-climatic conditions of the North China Plain, organic N forms were quantified in the topsoil with different manure and chemical fertilizer treatments in a 15-year fertilizer experiment in a Chinese calcareous alluvial soil. Soil total N （TN） and various organic N forms were significantly influenced by long-term application of chemical fertilizer and manure. TN, total hydrolysable N, acid-lnsoluble N, amino acid N and ammonium N in the soil increased significantly （P 〈 0.05） with increasing manure and fertilizer N rates, but were not influenced by increasing P rates. Also, application of manure or N fertilizer or P fertilizer did not significantly influence either the quantity of amino sugar N or its proportion of TN. Application of manure significantly increased （P 〈 0.05） hydrolysable unknown N, but adding N or P did not. In addition, application of manure or N fertilizer or P fertilizer did not significantly influence the proportions of different soil organic N forms.

Partial organic substitution weakens the negative effect of chemical fertilizer on soil micro-food webs

Soil biotic communities play vital roles in enhancing soil nutrient cycling and soil fertility.Long-term excessive nitrogen(N)application is disadvantageous to the stability of soil food webs and affects arable soil health and sustainable utilization.Proper organic substitution is essential to improve soil health and alleviate the disadvantages of excessive chemical fertilization.However,the biological effects of various organic amendments on soil micro-food webs are poorly understood.In order to explore the effects of various organic amendments including stover,biochar and manure on soil micro-food webs(microbial and nematode communities),a field plot experiment with maize having five treatments viz.,100%urea(100%N),70%urea(70%N),70%urea plus stover(Stover),70%urea plus cattle manure(Manure)and 70%urea plus biochar(Biochar)was conducted.Manure treatment increased the carbon(C)to N use efficiency of soil microbes,which contributed to the retention of soil C,while Biochar treatment elevated soil organic C(SOC)and soil p H.Additionally,Biochar treatment mitigated the negative effects of soil acidification on the soil micro-food web and reduced the abundance of plant parasites.Overall,the biological effect of organic amendments was distinguished from chemical fertilization(100%N and 70%N)through principal co-ordinates analysis.Negative relationships among soil properties,microbial and nematode biomass in the 100%N treatment were diminished in treatments where chemical fertilizer was reduced.The bottom-up effects on soil food webs were observed in organic substitution treatments.In conclusion,organic amendments improved soil fertility by regulating soil microbial and nematode communities in the cropland ecosystem,alleviated the negative effects of chemical fertilizer on the micro-food webs and controlled the trophic cascades among soil biota.

Effect of different fertilizers on methane emission from a paddy field of Zhejiang, China

Methane emissions from Chinese paddy soil (Zhejiang Province) were measured over the rice growing seasons. Different fertilizers (organic and chemical) were applied, emissions of methane were high during two periods(5 days after peak tillering and 7 days after heading flowering stage) and significant effect of fertilizers was observed. Methanogenic activities in soils treated with organic manures were obviously higher than those with chemical fertilizers. Among the organic manured fields the maximum methane emission from green manure, biogas residue and beef manure treatment were 52, 20 and 19 times respectively of that given by control, and among chemical fertilizers it was NH\-4HCO\-3>CO(NH 2) 2>(NH 4) 2SO 4>NH 4Cl>NaNO 3 with 2\^4, 2, 1\^5,1\^3 and 0\^2 times respectively of that from control.

Yield and Quality Response of Ryegrass, Egyptian Clover and Their Mixtures to Different Sources of Fertilizers

Two field experiments were conducted during two successive winter seasons of 2008/2009 and 2009/2010 to investigate the potentialities of mixing Egyptian clover with ryegrass under bio, organic and mineral fertilization treatments and their combination to increase forage yield and quality grown under sandy soil conditions. The experiment included the combination of five mixing ratios (Egyptian clover alone, ryegrass alone, 75% Egyptian clover: 25% ryegrass, 50% Egyptian clover: 50% ryegrass and 25% Egyptian clover: 75% ryegrass) and eight fertilizer sources, which include control, organic fertilization, bio fertilization, chemical fertilizer, organic + bio fertilizer, organic + chemical fertilizer, bio + chemical fertilizer and combination of organic and chemical and bio fertilizers. The obtained results indicate the superiority of 75% E. clover: 25% ryegrass mixture fertilizedby Bio + O + N in fresh and dry forage production. On the other hand, it reported the lowest dry weight of weeds g/m2. Chemical analysis of forage plants showed that the mixture of ?75% E. clover: 25% ryegrass surpassed that of other treatments yield for crude protein, ether extract and ash. The results also revealed that the highest record of DCP, crude fiber and TDNY was obtained by forage mixture of 75% E. clover: 25% ryegrass fertilized with Bio + O + N. Such higher yield of these characters hassecured a balanced ratio which is really needed for ruminants ration.

Soil Chemical Analysis of Kazi and Kazi Organic Tea Garden and Compared to Ordinary Tea Gardens of Bangladesh

Tea is grown in Bangladesh under marginal climatic and soil conditions. Its production is greatly influenced by many physical, chemical, biological and natural factors. The increasing land use intensity without adequate and balanced use of chemical fertilizers and with little or no use of organic manure has caused severe fertility deterioration of our soils resulting in stagnating or even declining of crop productivity. The need of the hour is to achieve substantially higher crop yield than the present yield levels from our limited land resources on a sustainable basis. A feasibility study was carried out of one and only organic tea garden namely Kazi & Kazi Tea Estate at Panchaghar and compared to ordinary tea gardens located at Sylhet namely Zareen Tea Estate, Nurjahan Tea Estate and Malnichara Tea Estate as secondary data to investigate the fertility status of soil. Results of the present study showed that soil solutions were acidic in nature in all seasons. Medium to high soil organic matter, medium to high available iron and phosphorous, and low availability of potash showed that soils were not sufficiently fertile for crop production. Student t-test values of all the parameters with control sample showed statistically significant results for SOM and available P. The critical values have been fixed at 0.1% for N and 1% for OM, 10 μg/g for P, 80 μg/g for K, 25 μg/g for Mg, 90 μg/g for Ca, 2 μg/g for Zn and 20 μg/g for S. The nutrient status is much higher in Kazi & Kazi organic tea estate in compared to other ordinary tea estates in Bangladesh.

有机肥替代化肥对立式深旋松耕马铃薯产量及水肥利用效率的影响

旨在研究立式深旋松耕作条件下有机肥替代部分化肥对马铃薯水肥利用和产量的影响,为实现水肥资源高效利用和绿色生产提供依据。设置全膜覆盖立式深旋松耕不施肥(VP),全膜覆盖立式深旋松耕施化肥(VPF),全膜覆盖立式深旋松耕有机肥替代60%化肥(VPO)3个处理。测定土壤含水量、叶绿素相对含量(SPAD)、叶面积指数(LAI)、块茎产量,计算贮水量、阶段耗水量和水肥利用效率等。结果表明:与VP相比,VPO和VPF均提高了马铃薯群体叶面积指数(LAI)和叶片SPAD值,二者均减慢了马铃薯块茎膨大期后的LAI和叶片SPAD值降低幅度,延长了光合期。2018-2020年,VPO和VPF均降低了土壤贮水量,尤其是收获期较VP降低了6.45%~18.33%;VPO降低了花前耗水量和水分利用效率,同时增加了花后耗水量,花后耗水量较VPF和VP增加了20.61~92.74 mm。VPO降低了肥料贡献率,提高了肥料的农学效率和偏生产力,较VPF分别提高了37.66%~201.22%和117.94%~165.29%;VPO和VPF都增加了马铃薯的块茎产量和商品率,块茎产量较VP增加了10.66%~68.39%和19.35%~93.16%。因此,立式深旋松条件下有机肥替代部分化肥可延长叶片光合功能期,改变了马铃薯的耗水进程,没有降低块茎产量,同时还提高了商品率和肥料的农学效率,是资源高效和作物增产的养分管理模式。

化肥减量配施有机肥对花生土壤有机碳及其组分的影响

为了探究化肥减量配施两种不同黄腐酸钾有机肥对土壤有机碳(SOC)及其组分的影响,采取盆栽试验模拟大田花生种植,以不施肥、纯施化肥为对照,设置100%化肥配施100%有机肥、75%化肥配施25%有机肥、50%化肥配施50%有机肥、25%化肥配施75%有机肥和施用100%有机肥处理,探讨了SOC、可溶性有机碳(DOC)、微生物生物量碳(MBC)、易氧化有机碳(LOC)和惰性有机碳(ROC)在花生不同生育期内的含量特征。结果表明:化肥减量配施有机肥各处理SOC及其组分含量在花生各生育期均表现为:花针期显著高于结荚期和成熟期,其中DOC和MBC含量结荚期显著高于成熟期(P<0.05);各处理SOC及其组分含量均表现为:25%化肥配施75%生化黄腐酸钾处理显著高于不施肥、单施化肥和单施有机肥处理,50%化肥配施50%矿源黄腐酸钾处理显著高于不施肥、单施化肥和单施有机肥处理;其中花针期25%化肥配施75%生化黄腐酸钾处理SOC、DOC、MBC、LOC和ROC含量分别为133.0 g/kg、284.4 mg/kg、269.7 mg/kg、30.76 g/kg和111.2 g/kg,50%化肥配施50%矿源黄腐酸钾处理SOC、DOC、MBC、LOC和ROC含量分别为130.9 g/kg、250.5 mg/kg、251.7 mg/kg、29.86 g/kg和110.8 g/kg。综上,化肥减量配施生化黄腐酸钾对SOC及其组分含量的影响整体优于配施矿源黄腐酸钾,化肥减量配施黄腐酸钾花针期含量显著高于结荚期和成熟期(P<0.05),其中25%化肥配施75%生化黄腐酸钾处理对提升SOC及其组分含量效果最佳。

磷肥有机替代、秸秆还田对土壤化学性质和棉花产量及其构成的影响

新疆有机肥资源丰富,探索磷肥有机替代、秸秆还田的外源肥料投入对土壤化学变化、棉花产量及其构成的影响,为深入了解当前棉田肥力和确定棉花减磷增效的技术服务着力点提供参考依据。经国家灰漠土肥力与肥料效益监测基地5年田间微区定位试验,在膜下滴灌条件下设置7个施肥处理,T1:不施肥,T2:不施磷,T3:常规施化肥磷100%,T4:有机肥磷替代25%化肥磷,T5:有机肥磷替代50%化肥磷,T6:化肥磷100%+25%有机肥磷,T7:化肥磷100%+秸秆还田。于2022年采集土壤样品,探明不同比例磷肥有机替代、秸秆还田对土壤化学性质、磷素有效性特征和棉花产量及其构成的影响。研究结果表明:(1)在外源肥料投入量(有机肥和化肥)均为等氮磷用量的条件下,磷肥有机替代、秸秆还田有利于加速土壤养分转化,增加土壤速效养分、全量养分含量。速效氮、有效磷、速效钾含量增幅分别在3.0%~25.3%、29.2%~120.1%、70.1%~99.1%之间,各速效养分含量依次与外源肥料投入后增量最高的T6、T5、T5处理相比,年均分别增长3.12、1.69、30.75 mg·kg^(-1)。全氮、全磷、全钾含量增幅分别在21.1%~43.9%、1.59%~41.3%、9.3%~33.6%之间,各全量养分含量依次与外源肥料投入后增量最高的T6、T6、T5处理相比,年均分别增长0.04、0.05、1.36 g·kg^(-1)。整体上有机替代、增施有机肥和秸秆还田对促进土壤养分的转化效果比单施化肥好,且长期施用有机肥的效应优于秸秆还田。(2)耕层土壤有机质含量随有机肥替代量的增加而增加,50%的有机替代其有机质含量显著最高(12.21 g·kg^(-1)),年均增长0.4 g·kg^(-1),最小增量T1~T2与最大增量T1~T5相比,增加1.04~3.44 g·kg^(-1),增幅为11.86%~39.22%,总体表现为正效应。相对较高的土壤pH和盐含量是限制棉花高效生产的主要因素,有机肥和秸秆还田对土壤pH和含盐量整体起到降低的作用,最大降幅pH的T1与T5、盐含量T5与T3相比分别下降3.07%、24.48%,总体表现为负效应。配施有机肥和秸秆还田增强了土壤供氮能力和磷素活化能力,土壤磷活化系数从1.52%提升到2.78%。由于受新疆石灰性土壤自然特性及气候条件限制,综合C/N、C/P、N/P表明,灰漠土有机质处于缺乏状态。(3)磷肥有机替代和秸秆还田均能够维持或促进棉花增产,在密度为24万株·hm^(-2)的试验种植模式下,连续5年常规施肥、25%的有机替代、50%的有机替代、增施有机肥、秸秆还田其籽棉产量分别达4173.13、4196.72、4805.10、5035.51、4830.98 kg·hm^(-2),综合土壤养分指标、肥料投入、棉花产量分析,50%的有机替代在节约磷肥用量的前提下对棉花增产效果最佳,与T1、T2、T3相比,分别显著增产20.49%、18.62%、15.14%。因此,研究认为当下应用50%的有机替代技术,即施磷(P_(2)O_(5))60 kg·hm^(-2)和配施羊粪9784 kg·hm^(-2),较为可行。

有机肥氮部分替代化肥氮对间作珠芽魔芋生长及养分积累利用的影响

为探索胶园间作珠芽魔芋的合理施氮方法,对有机肥氮部分替代化肥氮对珠芽魔芋生理特性、产量、品质及养分积累利用的影响进行了研究。研究设6个处理,分别为不施氮对照(T1)、当地习惯化肥氮用量(N 450kg/hm^(2))(T2)、80%习惯化肥氮用量+20%有机肥氮用量(T3)、80%习惯化肥氮用量(T4)、60%习惯化肥氮用量+20%有机肥氮用量(T5)、30%习惯化肥氮用量+50%有机肥氮用量(T6)。成熟期测定珠芽魔芋叶片形态指标、叶面球茎数量及倒伏株数、地下球茎产量、可溶性糖、淀粉、葡甘聚糖含量、氮磷钾含量及氮肥利用率。结果表明:与纯施化肥氮相比,有机肥代替部分化肥珠芽魔芋株高、茎粗、叶面球茎数量、繁殖系数增加,抗倒伏能力增强,提高了地下球茎氮肥利用率、产量、单株鲜重、膨大系数及氮、磷、钾吸收量。胶园间作珠芽魔芋的合理施氮模式为80%化肥氮+20%有机肥氮或者30%化肥氮+50%有机肥氮。

山东省小麦玉米秸秆资源分布与还田减肥潜力

【目的】山东地处华北地区,是我国小麦玉米主产省份。明晰其秸秆资源的空间分布特征及秸秆还田的养分替代潜力,可为推进全省秸秆综合高效利用和农田化肥合理减量增效提供决策依据。【方法】基于统计年鉴资料和文献调研数据,利用草谷比法对2019—2021年山东省不同地区小麦玉米秸秆年均产量及还田情景下的化肥可替代量进行测算。【结果】2019—2021年山东省小麦和玉米秸秆年均产量分别为2928万t和2252万t,两种秸秆资源的区域占比表现为鲁北(34.9%、34.7%)>鲁西南(27.6%、24.9%)>鲁中(20.2%、21.4%)>鲁东(9.1%、11.3%)>鲁东南(8.2%、7.8%)。单位面积小麦秸秆可收集量排序为鲁北(5573 kg·hm^(-2))>鲁西南(5380 kg·hm^(-2))>鲁中(5361 kg·hm^(-2))>鲁东南(5088 kg·hm^(-2))>鲁东(4968 kg·hm^(-2)),玉米秸秆可收集量排序为鲁西南(5121 kg·hm^(-2))>鲁北(5034 kg·hm^(-2))>鲁东南(4807 kg·hm^(-2))>鲁中(4790 kg·hm^(-2))>鲁东(4709 kg·hm^(-2))。秸秆产量较高的菏泽、德州、聊城、济宁和潍坊五市的小麦和玉米秸秆总占比分别为57.5%和55.5%,而秸秆产出较少的东营、淄博、日照和威海四市的两种秸秆总占比分别仅为7.2%和8.0%。全省小麦秸秆N、P2O5、K2O养分年均资源量分别为13.94万t、5.13万t和50.90万t,玉米秸秆N、P2O5、K2O养分资源量分别为16.65万t、6.58万t和36.60万t。区域尺度上单位面积小麦秸秆还田当季的N、P2O5、K2O养分理论可替代化肥的量分别为16.7—18.7、7.8—8.7和110.4—123.8 kg·hm^(-2),玉米秸秆还田的N、P2O5、K2O养分可替代化肥的量分别为25.4—27.6、11.8—12.8和83.2—90.5 kg·hm^(-2)。【结论】山东省不同地区的小麦玉米秸秆资源总量及单位面积可收集量存在一定差异,应因地制宜加强秸秆高效利用;秸秆还田利用情景下需考虑还田秸秆的替代化肥潜力,以促进化肥减量增效和农业绿色发展。

生物有机肥与化肥减量配施对土壤养分及烟叶产质量的影响

为减少化肥的过量施用,提高湖南宜章植烟土壤肥力和烟叶生产效益,以烤烟品种‘K326’为材料,采用田间试验研究了不同比例生物有机肥与化肥减量配施对土壤养分及烟叶产量与品质的影响。结果表明:增施适当比例生物有机肥配合化肥减量能不同程度地改善土壤肥力质量,促进烟株的生长。随着生物有机肥比例的增加与化肥用量的减少,烤烟的各项生长农艺性状、感官评吸质量、产量、产值以及上等烟比例呈先升后降的趋势。其中,以减量20%化学追肥的T2处理对烟株的生长和烟叶的品质表现最好。与常规施肥的对照(CK)相比,烟草株高、有效叶片数和最大叶面积分别增加8.24%~17.00%、13.81%~23.22%和12.63%~16.86%,C3F烟叶中总糖和钾含量分别达到26.51%~30.01%和2.16%~2.86%,C3F和B2F烟叶的感官评吸质量分别提高1.67%~2.98%和3.12%~4.10%,烟叶产量、上等烟比例和产值分别提高3.76%~6.58%、3.38%~3.79%和8.24%~9.58%。研究结果为湘南植烟区应用生物有机肥与化肥减量配施提供了科学参考依据。