Effects of Integrated Organic and Inorganic Fertilizers on Yield and Growth Parameters of Rice Varieties

We investigated the effects of integrated organic and inorganic fertilizers on the growth and yield of indica rice variety Manawthukha and japonica rice variety Genkitsukushi.In a split-plot design,the two rice varieties were assigned as main plot factors,and the integrated treatments were the subplot factors,including no-N fertilizer(N0),50%chemical fertilizer(CF)(CF50),100%CF(CF100),50%CF+50%poultry manure(PM)(CF50PM50),50%CF+50%cow manure(CM)(CF50CM50),and 50%CF+50%compost(CP)(CF50CP50).CF100 was equivalent to N at 85 kg/hm2.Manure was applied based on the estimated mineralizable nitrogen(EMN)level,which is dependent on total N(%)of each manure type.Manawthukha rice plants were taller with higher tiller number and dry matter content.However,higher soil-plant analysis development(SPAD)values were measured in Genkitsukushi throughout the crop growth period,resulting in higher seed-setting rate(%)and greater yield.At the same N level,CF50PM50 application in both rice varieties resulted in higher SPAD values,plant height and tiller number than CF100.CF50PM50 containing total N more than 4%supplied synchronized N for the demands of the rice plants,resulting in maximum dry matter,yield and yield components.CF50CM50 and CF50CP50 treatments containing total N less than 4%resulted in lower yields which were similar to CF100.These results indicated that integrating organic and inorganic fertilizers enhanced growth parameters and yields of Manawthukha and Genkitsukushi,while reducing the dose of chemical fertilizer.

Combined Application of Organic and Inorganic Fertilizers on Black Soil Fertility and Maize Yield

By two years （2007-2008） located fertilizer experiment, the effect of long-term combined application of organic and inorganic fertilizers on black soil fertility and crop yield was investigated in Shuangcheng City, Heilongjiang Province. The results showed that the combined application of organic and inorganic fertilizers could increase the organinc matter, alkaline nitrogen, available phosphorus and available potassium. At the same time, the increasing application of organic fertilizer could reduce the soil bulk density and improve the field moisture capacity. Field moisture capacity and organic matter of the combined application of high quantities of organic manure and inorganic fertilizers AtB5 treatment increased the fhstest, organic matter increased by 3.33 g. kg and field moisture capacity increased by 11.25% than the beginning of the experiment. Under the same fertilization, the combined application of organic and inorganic fertilizers＇ increasing production range was higher than the single chemical fertilizers＇ which was from 0.8% to 9.4%. The results showed that the combined application of organic and inorganic fertilizers could increase the nutrient contents of soil and also was the highest productivity contribution to black soil fertility. It was the best fertilization structure of increasing productivity level and improving the soil fertility.

Combined Effect of Organic Manures and Inorganic Fertilizers on the Growth and Yield of Hybrid Rice (Palethwe-1)

We investigated the effect of combining organic and inorganic fertilizers on the growth and yield of hybrid rice (Palethwe-1) in the dry and wet seasons of 2015. Four quantities of inorganic fertilizer were used in the main plot [0%, 50%, 75%, and 100% nitrogen, phosphorus, and potassium (NPK)] based on the recommended amounts of 150 kg N ha-1, 70 kg P2O5 ha-1, and 120 kg K2O ha-1, while different organic manures were applied to subplots [no organic manure (O0), cow manure (Oc), poultry manure (Op), and vermicompost (Ov);all at 5 t·ha-1] as part of a split-plot experimental design with three replicates. In both seasons, significant differences in growth parameters including number of tillers hill-1, soil-plant analysis development (SPAD) values, total dry matter, yield, and yield components were observed in plants supplied with different inorganic fertilizers. The 100% NPK (I100) fertilizer produced the maximum yield but similar yields were achieved in plots supplied with 50% NPK (I50) and 75% NPK (I75). Significant differences in growth and yield parameters were also found in crops supplied with organic manures. Although identical quantities were supplied, Op produced the best growth parameters in both seasons including total dry matter, yield, and yield components. Oc also performed well. Combining inorganic and organic fertilizers demonstrated that I50 together with Op (5 t·ha-1) provided similar growth, total dry matter, and yield parameters to I100 in both seasons. Oc (5 t·ha-1) plus I75 also achieved similar yields to I100. This study demonstrates that the combined application of inorganic fertilizers and organic manures has the potential to reduce chemical fertilizer usage without decreasing the yield of hybrid rice, and can enhance the growth, yield, and yield components of Palethwe-1.

Evaluation of Economic Importance of Locally Produced Manure over Inorganic Fertilizer for Maize Production: Vegetative Performance and Cost Implication

Background: Crops of economic importance like Maize are preferred to other crops with capacity of giving the highest yields, having the ability to help alleviate poverty within the African continent. The consistent use of inorganic fertilizers has great adverse effect on soil structure. The quest to seek alternative method of boosting maize production is imminent to avoid further soil degradation. Most plants form symbiotic relationships with mycorrhizae and improve nutrients uptake by host plants. Objectives: The aim of this study is to examine the effect of mycorrhizae in local manure production on development of maize, in comparison with inorganic fertilizer application and its cost implication. Methods: The experiment involved samples of starter soil from 7 local governments. Organic waste was added to starter soil, each having three replicates. Nine other replicates served as non-inoculated controls and nine served for fertilizer application at 50 g, 100 g and 150 g. One [1] gram of Maize sown in 50 ml pot contains soil at different treatment levels 50 g, 100 g, and 150 g. After two weeks, samples were transplanted in an open field. Results: The result showed plots treated with locally produced fertilizer, significantly influenced plant height, culm diameter, number of leaves and leaf broadness in comparison to inorganic fertilizer, which showed 53%, 47% respectively. Conclusion: Cost production of a bag of organic fertilizer was one-fourth cheaper compared to an inorganic fertilizer price from an open market.

Growth, Yield and Yield Characteristics of Three Pepper Cultivars to Fertilizers Application in the Mount Cameroon Region

This study determined the effects of organic and inorganic fertilizers on growth and yield of three pepper cultivars in the Mount Cameroon Region. Pepper seedlings were treated with six treatments (T1 = no fertilizers (control), T2 = 250 Kg/ha NPK 20:10:10, T3 = 350 Kg/ha NPK 20:10:10, T4 = 450 Kg/ha NPK 20:10:10, T5 = 20 Mg/ha poultry manure (PM), T6 = 30 Mg/ha PM). The effects of fertilizers had a significant effect on vegetative growth and yield of Capsicum chinense cv. “Big Sun” plants had the maximum plant height (39.09 cm) and mean collar diameter (6.02 mm) in plots treated with poultry manure at 20 Mg/ha (T5) and 30 Mg/ha (T6) respectively. The highest yield (33.63 Mg/ha) was in Capsicum chinense cv. Safi plants supplied with 30 Mg/ha poultry manure (T6) and the lowest yield (10.44 Mg/ha) was in Capsicum frutescens in control plots (T1). The highest fruit diameter (11.08 mm) and longest fruits (18.39 mm) were observed in Capsicum chinense cv. Big Sun plants supplied with 30 Mg/ha poultry manure. Capsicum frutescens fruits had the highest concentration of N (2.39%), P (0.42%) and K (3.06%). Essential oils analysis shows that there were 179 essential oils from pepper fruits of Capsicum chinense cv. Safi, with major essential oil been 3,4-dimethyl-benzaldehyde and main essential oils were alpha Terpinene and alpha Pinene based on their abundance. Fruits of Capsicum chinense cv. Big Sun had two-hundred and eight essential oils with major essential oil been 1,3,5-Trimethyl-1-H-pyrazol-4-amine and main essential oils were Caryophyllene oxide and Cymene, based on their abundance. Fruits of Capsicum frutescens had one-hundred and eighty-one essential oils with major essential oil been Limonene, and main essential oils were Carvacrol and D-limonene with respect to abundance. Results show that 20 Mg/ha poultry manure was the most cost effective in the production of pepper in Buea Cameroon.

The Application of Fertilizer and AMF Promotes Growth and Reduces the Cadmium and Lead Contents of Ryegrass (Lolium multiflorum L.) in a Copper Mining Area

Heavy metal-polluted soil was collected from the Pulang copper mine in Shangri-La City,Yunnan Province,Southwest China.The effects of fertilizer(organic and inorganic)and arbuscular mycorrhizal fungi(AMF)on ryegrass(Lolium multiflorum L.)growth,root morphology,mineral nutrition and cadmium(Cd)and lead(Pb)contents were investigated by pot experiments.The results showed that both fertilizer and AMF significantly ameliorated the root morphology and mineral nutrition,reduced the Cd and Pb contents,and promoted the growth of ryegrass.Among all treatments,the combined application of organic–inorganic compound fertilizer with AMF had the highest effect,resulting in increases in root length,surface area and branch number by 2.3,1.1,and 3.9 times,respectively;an 88%increase in plant biomass;a nitrogen content increase of 2.3 and 1.2 times,and phosphorus content increase of 62%and 68%in shoots and roots,respectively was also recorded as well as decreases in Cd content by 34%and 62%and Pb content by 47%and 34%in shoots and roots,respectively.Twofactor analysis showed that both fertilizer and AMF significantly promoted ryegrass growth(plant height,biomass,chlorophyll content,root length,nitrogen and phosphorus content)and reduced the Cd and Pb contents in roots,and there was a synergistic effect between them.Moreover,the nitrogen and phosphorus contents were very significantly positively correlated with the shoot and root biomasses but very significantly negatively correlated with the Cd and Pb contents of ryegrass.Thus,the application of fertilizer and AMF synergistically improved ryegrass growth on polluted soils in the copper mining area.

Variations in Optical Scattering and Backscattering by Organic and Inorganic Particulates in Chinese Lakes of Taihu, Chaohu and Dianchi

This study presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inland lakes(the Taihu Lake, the Chaohu Lake and the Dianchi Lake) based on in situ measurements taken at 119 sites. We modeled the particulate scattering spectra using a wavelength-dependent power-law function, finding that the power-law exponents in the Taihu Lake and the Chaohu Lake differ from those in the Dianchi Lake but are similar to the values in the U.S. coastal waters. In contrast to the open ocean, the backscattering properties in the three lakes can not be determined only from chlorophyll-a concentration. The backscattering ratio spectra exhibit a wavelength dependence feature in all three lakes, generally decreasing with the increasing wavelength. Analysis results of the correlations between the backscattering ratio and the individual water quality parameters clearly show that there are distinctive relations among the three lakes, attributed primarily to different compositions of optically active materials in the three lakes. Analysis of the mass-specific scattering and backscattering coefficients shows that the coefficients at wavelength 532 nm in the Taihu Lake and Chaohu Lake are similar, but they are apparently different from those in the Dianchi Lake. Lastly, Model I multiple linear regressions were adopted to partition the mass-specific cross-sections for scattering and backscattering into organic and inorganic cross-sections to further interpret the scattering and backscattering properties. The relative contribution of organic and inorganic particulates to scattering and backscattering is clearly different among the three lakes. The scattering and backscattering properties of the particulates in the three inland lakes vary significantly based on our collected data. The results indicated that the existing semi-analytical water quality retrieval models of the Taihu Lake can not be applied perfectly to the Chaohu Lake and the Dianchi Lake.

Complementary effects of organic and mineral fertilizers on maize production in the smallholder farms of Meru South District, Kenya

Low soil fertility is a major constraint to maize production in the small holder farms of Meru South District. This is mainly attributed to the mining of nutrients due to cropping without external addition of adequate nutrients. Mineral fertilizers are expensive hence un affordable by most small holder farmers. The use of organic matter to increase and maintain soil fertility is being considered as a solution to help the low-income small holder farmers. A study was conducted in Mucwa location, Meru South District to determine the levels of complementarity between organic and mineral N amendments on maize yields and their influence on soil chemical properties. The experiment was set in a complete randomized block design (CRBD) with three replicates. The treatments were compared with the response obtained from control. The general soil fertility parameters changed slightly with Calcium, Magnesium and Potassium increasing in all treatments. The organic Carbon and total Nitrogen was higher in treatments that received sole organic N sources than in sole mineral N and a combination of organic and mineral N sources. The highest maize grain yield of 4.8 t·ha-1 and 4.2 t·ha-1 were realized from sole application of calliandra during the 2005 Short rains and 2006 Long rains cropping seasons. Generally the maize grain yields were lower in treatments with mineral N alone compared to the treatments with organics. Treatments with sole calliandra and sole tithonia had the highest benefit cost ratio (BCR), followed closely by manure treatment. More so, integration of organic and mineral N sources resulted to higher net benefit and BCR than the application of the recommended rate of mineral fertilizers. Results obtained indicated that the use of either organic or combined organic/mineral N soil amendment appear to be superior to using mineral amendment sources alone.

Changes of Organic Matter, N, P and K Content of Soils in Red Soil Areas Under Long-Term Experiment

The content of organic matter （OM）, nitrogen （N）, phosphorus （P）, and potassium （K） in the three selected soils, including Calcaric Purpli-Orthic Primosols （purple sand-shale parent material）, Dystric Turbi-Anthric Primosols （quaternary red clay parent material） and Typic Udi-Sandic Primosols （granite parent material） were studied under a long-term experiment by using crop straw and inorganic fertilizers at the Hunan Red Soil Experiment Station of Chinese Academy of Agricultural Sciences. The results showed that the contents of OM, N, P and K in the three selected soils increased after 23 years application of crop straw and inorganic fertilizers, but the contents increased much less when crop straw or inorganic fertilizers was applied alone. The nutrient contents in the three soils developed from granite changed more remarkably than those in the soil derived from quaternary red clay and purple sand-shale. It was also found that the contents of OM, N, and P increased slightly in the treatments without applying fertilizers or returning the crop straw to the root bed. Combined application of inorganic fertilizers and crop straw could remarkably increase the contents of OM, alkalihydrolyzable N and available K, the positive correlation between application of organic fertilizers and increase of OM in soil did not always happened, it provided evidence for the relation between appropriate C/N ratio and accumulation of OM in soil. The increase of nutrient content was influenced by the soil properties. By comparing the contents of nutrient in 0-20 cm depth in the three different soils, it was concluded that the most increases of OM, alkali-hydrolyzable N, and available P were observed in Typic Udi-Sandic Primosols with the average increase by 3.03, 27.38, and 21.73 mg kg^-1, respectively. The available K increased in Dystric Turbi-Anthric Primosols with the average increase by 25.82 mg kg^-1, while it decreased in Calcaric Purpli-Orthic Primosols and Typic Udi-Sandic Primosols. It was concluded that the application of inorganic fertilizer and crop straw was important to improve the soil fertility for all of three selected soils. The straw return to the field had played a significant role for enhancement of the soil quality in the study areas. The application of inorganic fertilizer combined with the straw return to the fields could remarkably improve the soil fertility.

Effect of N Fertilizers on Root Growth and Endogenous Hormones in Strawberry

Endogenous hormones play an important role in the growth and development of roots. The objective of this research was to study the effect of four types of N fertilizers on the root growth of strawberry (Fragaria ananassa Duchesne) and the endogenous enzymes of indole-3-acetic acid (IAA), abscisic acid (ABA), and isopentenyl adenosine (iPA) in its roots and leaves using enzyme-linked immunosorbent assay. Application of all types of N fertilizers significantly depressed (P ≤ 0.05) root growth at 20 d after transplanting. Application of organic-inorganic fertilizer (OIF) as basal fertilizer had a significant negative effect (P ≤ 0.05) on root growth. The application of OIF and urea lowered the lateral root frequency in strawberry plants at 60 d (P ≤ 0.05) compared with the application of two organic fertilizers (OFA and OFB) and the control (CK). With the fertilizer treatments, there were the same concentrations of IAA and ABA in both roots and leaves at the initial growth stage (20 d), lower levels of IAA and ABA at the later stage (60 d), and higher iPA levels at all seedling stages as compared to those of CK. Thus, changes in the concentrations of endogenous phytohormones in strawberry plants could be responsible for the morphological changes of roots due to fertilization.

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.

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.

Effect of Land Use Conversion from Rice Paddies to Vegetable Fields on Soil Phosphorus Fractions

Excess phosphorus (P) from agricultural soils contributes to eutrophication in water bodies.Samples (n=60) were taken from sites where rice paddies have been converted to vegetable fields for 0,< 10,10-20,and > 20 years and analyzed for five inorganic P (Pi) fractions,three organic P(Po) fractions,and several soil parameters to investigate how land use conversion affects Pi and Po fractions in a peri-urban area of China with soils characteristic of many agricultural areas of Asia.Significant increases of 33,281,293,and 438 mg kg 1 were found for soluble and loosely bound Pi (SL-Pi),aluminum-bound Pi (Al-Pi),calcium-bound P i (Ca-Pi),and iron-bound Pi (Fe-Pi),respectively,after conversion from rice paddies to vegetable fields.Most of the increase in Pi was in the form of Fe-Pi,which increased from 8% of total P (TP) on paddy soil to 31% on the soil with > 20-year vegetable cultivation,followed by Al-Pi,which increased from 2% to 19% of TP.For Po fractions,there was no significant change in P concentrations.The conversion of land use from paddy fields to high intensity vegetable fields was causing significant changes in soil P fractions.Management practices were causing a buildup of soil P,primarily in the Fe-Pi fraction,followed by Ca-Pi and Al-Pi fractions.If current trends continue,a 30%-70% increase in TP could be expected in the next 20 years.Farmers in the area should reduce P application and use to maximize P uptake.

减量灌水及有机无机肥配施对西北灌区玉米光合生理、籽粒产量及品质的影响

针对绿洲灌区玉米生产中普遍水肥投入大、利用效率低等问题,通过研究不同灌水量和有机无机肥等氮配施对玉米光合生理、籽粒产量和品质的影响,以期获得最佳的灌水水平和有机无机肥等氮配施比例。2021—2022年,在绿洲灌区采用两因素裂区试验设计,主区为2个灌水水平(传统灌水和减量20%灌水),副区为5个有机无机肥等氮配施比例(全施无机氮肥、75%无机氮肥+25%有机肥、50%无机氮肥+50%有机肥、25%无机氮肥+75%有机肥和全施有机肥),探究玉米光合生理、籽粒产量和品质对不同水氮管理模式的响应特征。结果表明,与传统灌水(I2)相比,减量20%灌水(I1)降低了玉米叶面积指数(leaf area index,LAI)、光合势(photosynthetic potential,LAD)、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs),提高了胞间CO_(2)浓度(Ci)、籽粒蛋白质含量和籽粒苏氨酸含量;有机无机肥配施对玉米光合生理指标、籽粒产量和品质都有显著影响,随有机肥比例增加,有机无机肥配施对玉米的影响会逐渐从正效应变为负效应;与传统灌水结合全施无机氮肥(I2F1)相比,减量20%灌水结合75%无机氮肥+25%有机肥(I1F2)玉米平均叶面积指数(mean leaf area index,MLAI)提高了6.9%~7.1%,总光合势(total photosynthetic potential,TLAD)无显著变化;玉米吐丝期-蜡熟期LAI提高了5.0%~11.4%,吐丝期-蜡熟期LAD提高了7.5%~9.1%。I1F2较I2F1提高了玉米抽雄期-蜡熟期叶绿素含量(chlorophyll content,SPAD)、Pn、Tr和Gs,降低了Ci。2年内I1F2较I2F1玉米增产12.0%~12.5%,籽粒中蛋白含量提高了6.9%~18.9%,籽粒中苯丙氨酸、赖氨酸、苏氨酸、色氨酸、亮氨酸、异亮氨酸和缬氨酸含量分别提高了29.6%~43.3%、77.7%~93.3%、49.7%~51.5%、18.4%~28.6%、39.5%~46.0%、57.4%~78.1%和35.1%~41.3%。其他处理对玉米光合生理、籽粒产量及品质指标也有一定影响,但综合2年结果,I1F2影响更显著。因此,减量20%灌水(3240 m^(3)hm^(–2))结合75%无机化学氮肥(270 kg hm^(–2))配施25%有机肥(90 kg hm^(–2))是实现西北灌区玉米高产优质生产目标的适宜水氮管理模式。

Comparative effects of composted organic waste and inorganic fertilizer on nitrate leachate from the farm soils of northern Guam

The purpose of this study was to quantify the release of nitrate into vadose zone as well as the nitrogen-holding capacity of compost applied on calcareous soils of northern Guam amended with both inorganic fertilizer and composted organic waste,to examine potentially adverse effect of these nutrient materials to groundwater quality.Three different nitrogen levels each of the composted organic waste and the inorganic fertilizer were applied to corn(maize)(farmland)study plots for three consecutive seasons,two dry and one rainy season.During each season,soil organic matter(SOM,w/w%)content and carbon-nitrogen ratio(C/N,w/w%),were determined for analysis of the nitrogen-holding capacity of these calcareous soils.Nitrate levels in soil pore water were also determined for study of potential groundwater contamination.For three seasons,compost plots showed higher SOM%contents and lower C/N%than fertilizer plots.That is,compost-treated soils showed higher SOM content and adsorbed more nitrogen under normalized soil mass than did fertilizer-treated soils.Nitrate levels in pore water were generally higher on compost plots during early stages of corn but were generally higher on fertilizer plots during active leaf,tasseling,and maturity stages.During the rainy season,nitrate leachate seemed to increase,but this trend could not be confirmed because rainfall amounts were not measured.Overall,composted organic waste proved to be a good amendment for soil productivity and agricultural sustainability while reducing nitrate leachate from northern Guam farmland.

多样化培肥模式调控丛枝菌根真菌促进玉米磷素吸收

利用丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)从农田生态系统获取养分,是红壤作物吸收土壤磷(P)素的有效途径。针对我国南方红壤生物功能退化、P生物有效性低、作物产量低等问题,如何调控作物根际AMF群落,优化其与宿主的互惠共生关系,是突破红壤区作物P摄取瓶颈的关键。结合红壤旱地生态间作与有机(秸秆、猪粪、生物肥)无机肥料配施的4种多样化培肥措施,基于作物产量和红壤磷素活化水平,筛选最优培肥模式,并进一步利用扩增子高通量测序和显微观察等技术,解析红壤旱地最优培肥措施调控AMF群落组成,揭示优化的AMF群落激发宿主玉米磷素摄取机理。结果表明:相较于玉米单作配合常规化肥(Mo+NPK),花生/玉米间作结合秸秆/生物肥的有机无机配施(In+NPKSB)使红壤旱地全磷(TP)提高29.07%、有效磷(AP)提升1.35倍,且增强了玉米根内AMF群落科水平间的联系。该措施AMF定殖率是传统化肥措施的2.24倍,玉米根际酸/碱性磷酸酶(ACP/ALP)活性提高32.18%和41.66%,玉米生物量提高34.98%,产量提高67.27%。研究证实红壤旱地花生/玉米生态间作结合秸秆/生物肥有机无机配施的培肥措施可通过优化玉米根内AMF群落组成,促进土壤P活化,为在红壤旱地因地制宜推广可持续农业发展的集成应用提供理论依据。

有机无机肥配施对江苏滨海盐碱土农田生产力和碳库的影响

[目的]有机肥施用是江苏滨海轻度盐碱地主要的改土提质技术,本试验通过研究在有机替代模式下夏玉米种植系统农田生产力和土壤碳库的变化特征,探索在粉垄耕作模式下有机肥还田同氮肥减量的最佳比例。[方法]按照等氮量投入原则,以当地氮肥施用(CK)为对照,设置25%有机肥+75%氮肥(CT25)、50%有机肥+50%氮肥(CT50)、75%有机肥+25%氮肥(CT75)、有机肥全量替代氮肥(CT100)处理,开展粉垄耕作模式下不同比例有机肥替代氮肥玉米种植田间试验,对玉米农田生产力和土壤碳库指标进行测定。[结果]与氮肥全量施用相比,有机肥替代化肥比例在25%~50%时,玉米籽粒产量可增加8.74%~11.21%,其中CT25处理的玉米光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))、胞间CO_(2)浓度(C_(i))显著增加,土壤全氮、全磷、全钾、碱解氮、速效磷、速效钾含量均较单施氮肥显著增加,有机替代比例超过50%以上时玉米产量和土壤养分较纯施氮肥无显著变化。相较于纯施氮肥,有机肥替代比例在25%~75%时土壤碳储量提升9.47%~14.61%,这主要依赖于土壤有机碳含量和容重的显著增加。土壤有机碳含量和玉米产量呈显著的正相关关系。[结论]粉垄耕作模式条件下,有机肥替代氮肥在25%~50%可以显著改善土壤理化性质,增加土壤碳储量,提升农田生产力,可作为江苏滨海旱作玉米种植推荐施肥技术。

有机-无机肥配施对新疆核桃园土壤和叶片养分的影响

[目的]研究有机-无机肥配施对核桃园土壤和叶片养分的影响,筛选影响叶片养分的主要土壤化学因子,为新疆核桃园土壤养分资源高效管理提供科学依据。[方法]以新疆喀什地区叶城县核桃主栽区的10年生‘温185’核桃为研究对象,采用单因素完全随机区组设计,以当地主要的化肥施用类型(磷酸氢二铵和硫酸钾,YD)为对照,探究有机-无机肥配施(矿源黄腐酸钾和中量元素水溶肥,YZ)对核桃园土壤化学特性和叶片矿质元素的影响。[结果]与YD施肥措施相比,YZ处理显著降低了土壤pH、盐离子含量,提高了叶片矿质元素含量,但具有季节性差异。其中,5月,YZ处理显著提高了土壤NO_(3)^(-)-N(460.22%)、AK(46.46%)和叶片N(12.16%)、K(17.46%)、Zn(21.88%)元素含量;7月,YZ处理显著降低了土壤pH(2.21%)、EC(27.25%)、Cl^(-)-S(23.37%)、NH_(4)^(+)-N(61.09%)、AP(30.03%)、Na^(+)(13.24%)和叶片Cl^(-)-L(15.94%)元素含量(p<0.05),相反,显著提高了叶片N(4.16%)、P(13.25%)、Ca(20.73%)、Mg(44.04%)、Na(66.67%)、Fe(24.62%)、Mn(52.47%)、B(31.85%)元素含量(p<0.05);9月,YZ处理显著降低了土壤EC(20.45%)、NH_(4)^(+)-N(37.31%)、AP(21.74%)、Na^(+)(11.36%)含量(p<0.05),相反,显著提高了OM(22.17%)、NO_(3)^(-)-N(59.09%)、AK(56.47%)含量(p<0.05)。线性回归分析结果表明,土壤pH、Na+和Cl^(-)-S是新疆核桃园中影响核桃叶片矿质元素含量的重要土壤化学因子,增施有机肥并且降低土壤pH,有利于叶片N、P、K、Na、Fe、Zn元素的积累。[结论]YD处理提高了土壤EC、Na^(+)、Cl^(-)-S、NH_(4)^(+)-N等盐离子含量,长期施用可能会加剧新疆核桃园的土壤盐渍化水平;YZ处理可显著降低土壤pH、Na^(+)、EC、NH_(4)^(+)-N等盐离子含量,提高了叶片N、P、K、Fe等矿质元素含量,建议在新疆核桃主栽区核桃园,7月之前可通过有机-无机肥配施降低土壤盐渍化水平来减轻盐碱危害,同时平衡叶片矿质元素含量,而应尽量避免长期单一施用化肥。