Long-Term Application of Organic Manure and Mineral Fertilizer on N_2O and CO_2 Emissions in a Red Soil from Cultivated Maize-Wheat Rotation in China

A long-term field experiment was established to determine the influence of mineral fertilizer and organic manure on soil fertility. A tract of red soil （Ferralic Cambisol） in Qiyang Red Soil Experimental Station （Qiyang County, Hunan Province, China） was fertilized beginning in 1990 and N20 and CO2 were examined during the maize and wheat growth season of 2007-2008. The study involved five treatments： organic manure （NPKM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, and control （CK）. Manured soils had higher crop biomass, organic C, and pH than soils receiving the various mineralized fertilizers indicating that long-term application of manures could efficiently prevent red soil acidification and increase crop productivity. The application of manures and fertilizers at a rate of 300 kg N ha-1 yr-1 obviously increased NzO and CO2 emissions from 0.58 kg N20-N ha-~ yr-~ and 10565 kg C ha-~ yr-~ in the CK treatment soil to 3.0l kg N20-N ha-~ yr-~ and 28 663 kg C ha-~ yr-I in the NPKM treatment. There were also obvious different effects on N20 and CO2 emissions between applying fertilizer and manure. More N20 and CO2 released during the 184-d maize growing season than the 125- d wheat growth season in the manure fertilized soils but not in mineral fertilizer treatments. N20 emission was significantly affected by soil moisture only during the wheat growing season, and CO2 emission was affected by soil temperature only in CK and NP treatment during the wheat and maize growing season. In sum, this study indicates the application of organic manure may be a preferred strategy for maintaining red emissions than treatments only with mineral fertilizer. soil productivity, but may result in greater N20 and CO2

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.

Nitrogen and Phosphorus Runoff Losses from Orchard Soils in South China as Affected by Fertilization Depths and Rates

Fertilizers are heavily applied in orchards of the hilly and mountainous topography of South China and may increase nutrient loadings to receiving waters.A simple runoff collecting system was used to measure the effects of different fertilization treatments on total N and P concentrations of surface runoff in a Chinese chestnut (Castanea mollissima Blume) orchard in Dongyuan County,Guangdong Province,China.In such orchards,fertilizer was typically applied in two short furrows or pits on either side of each tree.Treatments included three application depths (surface,10cm and 20 cm),and three application rates (low,median and high).Results showed that 90.5% of the runoff water samples had a total N concentration higher than 0.35 mgL^(-1) and 54.2% had a total P concentration higher than 0.1 mgL^(-1).Fertilizer application at all depths and at all but the lowest rate significantly increased total N and P concentrations in runoff water.Fertilization with chemical compound fertilizer at a soil depth of 20cm produced significantly lower (P<0.05) total N concentration in runoff than both surface and 10-cm depth fertilization,and significantly lower (P<0.05) total P concentration in runoff than surface fertilization.Total N and P concentrations in runoff significantly increased with the application rate of organic fertilizers.With the exception of total P concentrations,which were not significantly different between the control and fertilization at a rate of 119 kg P ha-1 in organic form,all the other fertilization treatments produced significantly higher total N and total P concentrations in runoff than the control.A fertilization depth≥20cm and an application rate≤72 kg N ha^(-1) or 119 kg P ha^(-1) for compound organic fertilizer was suggested to substantially reduce N and P runoff losses from hillslope orchards and to protect receiving waters in South China.

Effects of long-term fertilization on soil gross N transformation rates and their implications

Application of fertilizer has been found to significantly affect soil N cycling. However, a comprehensive understanding of the effects of long-term fertilization on soil gross N transformation rates is still lacking. We compiled data of observations from 10 long-term fertilization experiments and conducted a meta-analysis of the effects of long-term fertilization on soil gross N transformation rates. The results showed that if chemical fertilizers of N, P and K were applied in balance, soil p H decreased very slightly. There was a significantly positive effect of long-term fertilization, either chemical or organic fertilizers or their combinations, on gross N mineralization rate compared to the control treatment（the mean effect size ranged from 1.21 to 1.25 at 95% confidence intervals（CI） with a mean of 1.23）, mainly due to the increasing soil total N content. The long-term application of organic fertilizer alone and combining organic and chemical fertilizer could increase the mineralization-immobilization turnover, thus enhance available N for plant while reduce N losses potential compared to the control treatment. However, long-term chemical fertilizer application did not significantly affect the gross NH4＋ immobilization rate, but accelerated gross nitrification rate（1.19; 95% CI： 1.08 to 1.31）. Thus, long-term chemical fertilizer alone would probably induce higher N losses potential through NO3– leaching and runoff than organic fertilizer application compared to the control treatment. Therefore, in the view of the effects of long-term fertilization on gross N transformation rates, it also supports that organic fertilizer alone or combination of organic and chemical fertilizer could not only improve crop yield, but also increase soil fertility and reduce the N losses potential.

Short-term influence of anaerobically-digested and conventional swine manure, and N fertilizer on organic C and N, and available nutrients in two contrasting soils

A three-year (2006-2008) field experiment was conducted at Swift Current and Star City in Saskatchewan to determine the short-term in-fluence of land-applied anaerobically digested swine manure (ADSM), conventionally treated swine manure (CTSM) and N fertilizer on total organic C (TOC), total organic N (TON), light fraction organic C (LFOC), light fraction organic N (LFON) and pH in the 0 - 7.5 and 7.5 - 15 cm soil layers, and ammonium-N, nitrate-N, extractable P, exchangeable K and sulphate-S in the 0 - 15, 15 - 30, 30 - 60, 60 - 90 and 90 - 120 cm soil layers. Treatments included spring and autumn applications of CTSM and ADSM at a 1x rate (10,000 and 7150 L·ha-1, respectively) applied each year, a 3x rate (30,000 and 21,450 L·ha-1, respectively) applied once at the beginning of the experiment, plus a treatment receiving commercial fertilizer (UAN at 60 kg·N·ha-1·yr-1) and a zero-N control. There was no effect of swine manure rate, type and application time on soil pH. Mass of TOC and TON in the 15 cm soil layer increased significantly with swine manure application compared to the control, mainly at the Swift Current site, with greater increases from 3x rate than 1x rate (by 2.21 Mg·C·ha-1 and 0.167 Mg·N·ha-1). Compared to the control, mass of LFOC and LFON in the 15 cm soil layer increased with swine manure application at sites, with greater increases from 3x rate than 1x rate (by 287 kg·C·ha-1 and 26 kg·N·ha-1 at Star City, and by 194 kg·C·ha-1 and 19·kg·N ha-1 at Swift Current). Mass of TOC and TON in soil layer was tended to be greater with ADSM than CTSM, but mass of LFOC and LFON in soil was greater with CTSM than ADSM. Mass of TOC, TON, LFOC and LFON in soil also increased with annual N fertilizer application compared to the control (by 3.2 Mg·C·ha-1 for TOC, 0.195 Mg·N·ha-1 for TON, 708 kg·C·ha-1 for LFOC and 45 kg·N·ha-1 for LFON). In conclusion, our findings suggest that the quantity and quality of organic C and N in soil can be affected by swine manure rate and type, and N fertilization even after three years, most likely by influencing inputs of C and N through crop residue, and improve soil quality.

A Field Study on Effects of Nitrogen Fertilization Modes on Nutrient Uptake,Crop Yield and Soil Biological Properties in Rice-Wheat Rotation System

Rational application of nitrogen （N） fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of microbes.The result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes （bacteria,actinomycetes,and fungi）.On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,respectively.Further,organic fertilizer replacement had a Shannon＇s diversity index （H） of 2.18,which was higher than that of other modes of single N fertilizer application.The results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.

Effect of Organic and Inorganic Amendments on the Phytoavailability of Phosphorus to Corn (<i>Zea mays</i>)

A pot experiment was conducted to investigate the effect of cow manure, city waste, chicken manure and TSP on the growth of corn (Zea mays) and phytoavailability of phosphorous (P) in soil. An air dried sandy loam soil was mixed with different amendments at rates equivalent to 0, 200, 400 and 800 mg P kg–1 soil based on total P. The plant height and leaf number increased in the plants grown in amended pots compared to control pot. The dry weight of shoots and roots in the control pot were 14.3 and 2.8 g, respectively. The shoot dry weights of corn increased from 43.8 to 76.6 g with the cow manure, 27.8 to 38.7 g with the city waste, 48.4 to 68.2 g with the chicken manure and 30.2 to 32.2 g with the TSP amendments when the P addition rates increased from 200 to 800 mg P kg–1 soil. Similar effects of these amendments and their rates were also found in the case of roots dry weights production. Phosphorus concentration in the plant parts increased with the P application from different amendments but the increase was higher with the TSP fertilizer and lower with the city waste amendments. Olsen P (measured after the plant harvest) increased with P application rates. The extractability of Olsen P from different amendments increased in this order: city waste < chicken manure < cow manure < TSP. Olsen P was strongly related with both shoot and root P concentration of corn (r = 0.910, p = 0.000), indicate suitability of Olsen P to predict plant available P. These results imply that cow manure and chicken manure could be recommended to use in the agricultural field for producing optimum yield.

The Effects of Manure, Lime and P Fertilizer on N Uptake and Yields of Soybean （Glycine max （L.） Merrill） in the Central Highlands of Kenya

Soybean （Glycine max （L.）） is one of the most important legume crops being introduced in the CHK （Central Highlands of Kenya） expected to increase yields. However, low levels of soil N （nitrogen） and other plant nutrients and soil acidity are seen as the major causes impairing goal achievement. To evaluate the influence of manure, lime, P （phosphorus） fertilizer and their combination on N uptake and soybean performance, an experiment was conducted in Embu ATC （Agricultural Training College） comprising 9 treatments, arranged in a Randomized Complete Block Design with 4 replicates in plots of 4 m×4.5 m. The study included manure （0, 5 and 10 t-ha-1）, lime （0 and 2 t.ha-1） and P fertilizer （0, 30 and 60 kg.P.hal）. The treatments significantly influenced N uptake and soybean yields. Both parameters responded well to application of manure both alone or combined to lime and TSP （triple super phosphate）. From these it was concluded that organic and inorganic resources have potential to enhance N uptake and soybean and other crops yields in CHK.

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。

配比施肥对槟榔幼苗肥料利用率及养分协同效应的影响

为了明确N、P、K肥对槟榔幼苗生长及营养吸收与利用的影响,从而确定合理的槟榔幼苗施肥技术。以槟榔幼苗为对象,采用“3414”肥料配比田间盆栽试验,测定不同施肥处理对槟榔幼苗营养吸收与分布及肥料利用率的影响。结果表明:(1)施肥提高了槟榔幼苗的生物量和肥料利用率;在氮磷钾平衡施肥时,氮肥和磷肥相对利用率达到最大;在不施磷肥,氮钾平衡施肥时,钾肥相对利用率达到最大;(2)槟榔幼苗地上部氮养分积累量是影响其生物量的主要因子,地下部磷养分积累量是影响其生物量的主要因子;(3)相关性分析与通径分析表明,氮与磷可协同促进槟榔幼苗生物量的增长,但会受到施钾量及钾肥相对利用率的制衡,3种元素协同促进植株生物量增长。因此氮肥和磷肥的相对利用率是槟榔幼苗施肥的关键指标。综上,氮磷钾配比施肥有利于槟榔幼苗的营养吸收和利用,以N∶P∶K=2∶2∶2(T6)配比施用效果较好。

适宜氮磷钾用量和配比协同促进盆栽牡丹营养和生殖生长

【目的】牡丹是我国著名的木本观赏植物,施肥不平衡严重影响盆栽牡丹的生长和观赏效果。研究开花前后氮、磷、钾不同施用量和配施比例对盆栽牡丹生长的影响,确定适宜的氮、磷、钾施用量及配比,为盆栽牡丹精准施肥提供理论依据。【方法】本研究以5年生牡丹‘紫二乔’为供试材料,采用“3414”不完全正交回归设计进行盆栽试验,结合隶属函数法评价牡丹的生长状况,利用肥料效应模型拟合牡丹植株的综合隶属函数值与施肥量之间的数学关系,得出牡丹最佳生长的氮、磷、钾肥推荐施肥量。【结果】牡丹开花前后施用氮磷钾肥显著影响植株株高、茎粗、冠幅、花径和单株花数(P<0.05),适宜氮磷钾用量和配比促进盆栽牡丹营养和生殖生长的协同提高。氮、磷、钾三因素配合处理的牡丹综合隶属函数值均大于缺素处理,缺素处理又大于无肥处理,N_(2)P_(2)K_(2)处理的综合隶属函数值(0.73)是N_(0)P_(0)K_(0)的3.17倍。氮磷钾对牡丹综合生长的影响表现为氮>磷>钾。氮、磷、钾肥对牡丹营养和生殖生长存在明显交互作用,任一肥料水平的过量或不足均会抑制牡丹植株生长,降低观赏效果。采用一元二次、二元二次、三元二次肥料效应函数方程拟合牡丹的综合隶属函数值和施肥量,二者相关性均达显著水平,综合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,得出牡丹开花前后氮(N)、磷(P_(2)O_(5))、钾(K_(2)O)的最优推荐施肥量分别为4.21、2.07、2.52 g/株,适宜的氮、磷、钾施肥比例为1∶0.49∶0.60。【结论】开花前后施用适量的氮、磷、钾肥可提高牡丹的农艺性状,促进牡丹的营养和生殖生长协同提高。氮、磷、钾的最优推荐施肥量为4.21、2.07、2.52 g/株,适宜的氮、磷、钾施肥比例为1∶0.49∶0.60。

不同磷水平对棉花养分吸收和磷肥利用效率的影响

为探讨北疆棉区不同施磷量对棉花养分吸收、磷肥利用效率、生物量和棉株氮磷化学计量比的影响,本研究以始于2018年的棉田土壤磷素肥力演替特征长期定位试验为研究对象,对5年等量氮钾不同磷水平施肥后棉田磷素和棉花养分吸收的响应进行分析。结果表明,施磷量的增加促进了棉株N、P、K养分吸收,棉株各器官N、P、K养分平均含量分别在1.75~38.27、1.46~11.26、3.11~24.31 g·kg^(-1)之间。综合肥料投入,施磷量为150 kg·hm^(-2)最有利于P素养分吸收和干物质积累。棉株各器官N∶P值变化范围在1.20~12.01之间,随着施磷量的增加,棉株茎、叶、蕾/铃/壳的N∶P降低,棉株生物量、籽棉产量随叶、蕾/铃/壳N∶P的降低而增加,本试验棉花生长更倾向于受N、P共同限制。磷肥利用率和磷肥农学效率随施磷量的增加呈先增后减的趋势,磷素盈余量随施磷量的增加而增加。在施磷量为150 kg·hm^(-2)时,磷肥利用率和磷肥农学效率均达到最高值,分别为10.20%和4.05 kg·kg^(-1),其磷素盈余为54.19 kg·hm^(-2),研究表明,在北疆灰漠土棉田施磷量为150 kg·hm^(-2)比较可行,值得推广应用。

不同增氧措施对牛粪有机肥矿化及烟叶生长的影响

通过增氧措施提升有机肥矿化速率,满足烤烟生长发育的需肥规律。本研究从2种物理增氧(打孔增氧与泵增氧)与3种化学增氧(过氧化钙、过氧化氢和过碳酸钠)中筛选出最利于土壤酶活性和烟株生长的增氧方式,在此基础上明确最佳增氧时间和增氧剂浓度。开展不同增氧方式田间试验,从田间产量、产值、有机肥矿化率及土壤微生物群落结构等方面评价增氧效果。结果表明:(1)综合烟株长势、农艺性状和土壤生态多样性等指标发现,化学增氧和物理增氧方式分别以过氧化钙增氧和泵增氧效果最佳。(2)牛粪有机肥增氧时间以12 h/d最优,过氧化钙用量以40 g/株为最优,二者根部干质量分别为对照的1.92倍和1.24倍。(3)田间应用牛粪有机肥联合过氧化钙增氧,遵义、毕节和黔西南的烟叶产值分别增加10.47%、12.48%和18.82%。过氧化钙增氧烟叶化学成分综合评分分别增加13.97、3.38和19.95分,工业可用性提升4.5个百分点。(4)与对照相比,打孔增氧使有机肥氮矿化率增加31.6%~57.1%,过氧化钙处理有机肥氮矿化率增加95.0%~138.9%。综上所述,打孔增氧和过氧化钙增氧可应用于田间生产,以提高碳氮转化效率,改善土壤微生物功能多样性,提升烟叶产量和品质。

有机肥料氮替代部分化肥氮对稻谷产量的影响及替代率

【目的】试图探索出有机肥料氮替代化肥氮的最适替代率,为研制水稻专用有机无机复合肥奠定基础。【方法】试验在江苏省常熟市进行,采用田间试验研究4个氮用量下(0、180、240和270kg·hm-2)有机肥料氮替代部分化肥氮对水稻(4007和常优1号)产量、氮肥利用率和土壤矿质态氮的影响。【结果】(1)与单施化学氮肥相比,氮用量为180kg·hm-2并且有机肥料氮的替代率在15%～30%或氮用量为240kg·hm-2并且有机肥料氮的替代率在10%～20%时,能够显著提高水稻的稻谷产量。两个水稻品种(4007和常优1号)的稻谷产量分别达到8242～10187kg·hm-2和10048～11654kg·hm-2;(2)与单施化肥相比,氮用量在180kg·hm-2并且有机肥料氮的替代率在15%～30%或氮用量在240kg·hm-2并且有机肥料氮的替代率在10%～20%时,两个水稻品种的氮素累积量分别为172.6～256.4kg·hm-2、185.9～235.6kg·hm-2,显著高于单施化学氮肥处理,此时,氮肥利用率也达最高,分别为36.6%～48.1%、34.3%～40.0%;(3)与单施化学氮肥相比,氮用量在180kg·hm-2并且有机肥料氮的替代率在15%～30%或者氮用量在240kg·hm-2并且有机肥料氮的替代率在10%～20%时可以获得较为平稳的氮素供应过程。【结论】有机肥料氮与化肥氮配施能获得比单施化学氮肥处理更高或持平的稻谷产量并有效地提高水稻的氮肥利用率。

辽西褐土施肥及养分循环再利用中长期试验Ⅲ.磷和氮在堆腐过程中的循环率及有机肥料中养分利用率

9年的试验结果表明 ,农产品中N、P经堆腐后损失率平均为 30 % .在丰产条件下 ,6 0 %的收获产品直接堆腐回田 ,可循环回田的养分量为N 5 5～ 70kg·hm-2 、P 9～ 11kg·hm-2 ,相当于这一系统中每年化肥N用量的 37%～ 4 7%和P肥用量的 36 %～ 4 4 % .有机肥料中N和P的表观利用率随施肥年限延长而有增长趋势 ,表明有残效叠加效应存在 .有机肥料中N和P的当季表观利用率 8年平均分别为 2 3%～5 0 %和 37%～ 6 5 % .通过此项研究可以证明 ,农业生态系统养分的循环再利用是保持土壤肥力 ,提高养分利用效率 ,减少化学肥料消费的重要措施 .

氮和磷在饲养-堆腐环中的循环率及有机肥料养分利用率

A five-year experiment indicated that the average loss rate of N and P in harvested products through a feeding-composting cycle was about 50% and 15%,respectively.Under high yield condition,the amount of recycled N and P from 80% harvested products and through a feeding-composting cycle in farming systems was about 3751 and 814 kghm-2,equivalent to 25%34% of N and 32%56% of P from chemical fertilizers applied each year to the systems.The apparent recoveries of N and P in organic manure increased with the prolongation of fertilization,indicating a synergetic residual effect existed,and was 61% and 39% in average in the five-year experiment.The use of nutrients recycled in the farming systems could not only improve soil fertility,but also increase the recoveries of nutrients and reduce the use of chemical fertilizers.

不同施肥制度对作物产量及肥料贡献率的影响

通过17年的长期定位肥料试验,研究了不同施肥制度对作物产量及肥料贡献率的影响,结果表明:化肥N、P、K的施用均能明显提高作物产量,其增产率分别为32.10%、15.06%、10.95%;循环回田的农家肥养分对作物增产有明显的残效叠加作用,且具有良好的稳产作用,可以满足作物对不同气候年景的适应性。在本试验中,若将保持养分循环再利用基础上施用NPK化肥视为最佳施肥制度,则在保持其他农业技术不变条件下,最大施肥贡献率为0.44。在下辽河平原土壤、气候和生产力水平等条件下,为保证作物持续高产,应同时施用化肥和循环肥。

有机肥氮替代化肥氮提高玉米产量和氮素吸收利用效率

【目的】有机肥替代部分化肥是实现中国化肥零增长的重要技术途径之一。利用在紫色土上8年定位试验研究有机肥氮连续替代化肥氮玉米生产力和氮素吸收利用效率的变化,为紫色土区合理利用有机养分资源和玉米施肥结构的调整提供科学依据。【方法】本试验为8年定位试验,试验施肥模式有5种:不施氮肥对照(CK)、农民常规施肥(FP)、化肥优化施用(OP)、在化肥优化的基础上有机肥(鸡粪)氮替代50%化肥氮(MF)、有机肥(鸡粪)氮替代100%化肥氮(OM)。试验研究了不同施肥处理下玉米产量、生物量和氮素吸收利用的变化。【结果】有机肥氮替代部分化肥氮能够显著增加玉米籽粒产量和生物量。相比常规施肥(FP)、有机肥氮替代100%化肥氮(OM)和化肥优化施用(OP),有机肥氮替代50%化肥氮处理(MF)的8年玉米籽粒平均增产率分别为13.7%、13.5%和12.5%,地上部生物量增产11.3%、7.0%和8.6%。与对照相比,各施肥模式均降低了玉米产量年度变异系数,提高了可持续指数和收获系数,其中有机肥氮替代50%化肥氮(MF)年度变异最小、可持续指数和收获指数最高。有机肥氮替代部分化肥氮促进了玉米对氮的吸收累积和向籽粒的转运。与化肥优化施(OP)和有机肥氮替代100%化肥氮(OM)处理相比,有机肥氮替代50%的化肥氮处理(MF)籽粒中氮素累积吸收量增加7.0%和29.6%,氮的总表观利用率提高2.5个百分点和26.5个百分点。有机肥氮替代50%化肥氮处理(MF)的氮肥偏生产力、氮收获指数和氮肥贡献率分别比OP提高6.2 kg·kg^(-1)、3.5个百分点和6.3个百分点,比OM提高6.6 kg·kg^(-1)、0.8个百分点和5.8个百分点。不同施肥处理每生产1 t玉米对氮素的需求量存在明显差异,化肥优化(OP)和有机肥氮替代50%的化肥氮(MF)处理生产1 t玉米籽粒对氮素的需求量(9.4 kg和10.8 kg)明显低于FP和OM处理(14.5 kg和12.9 kg),提高了氮素的生产效率。【结论】有机肥氮替代50%化肥氮显著提高了玉米经济产量和生物产量,提高了产量的稳定性和可持续性;促进了玉米对氮素的吸收和向籽粒的转运,提高了氮的利用效率。有机肥氮替代部分化肥氮是西南紫色土地区玉米增产稳产、氮肥增效的合理施肥方式。

长期免耕与施用有机肥对土壤微生物生物量碳、氮、磷的影响

通过设置在江苏省句容农科所的田间定位试验研究长期免耕及施用有机肥料对土壤微生物生物量碳、氮、磷的影响。结果表明 :经过 1 6年 32茬稻—麦水旱轮作后 ,表土层 ( 0～ 5cm)土壤微生物生物量碳、氮、磷含量比亚表层 ( 5～ 1 0cm)分别高 2 7.5 %、43.6%和1 1 %。与常规耕翻相比长期免耕处理表土层土壤微生物生物量碳、氮含量分别增加了2 5 .4%和 45 .4% ,而微生物生物量磷无明显变化规律 ;亚表层的土壤微生物生物量碳、氮、磷免耕与耕翻两种耕作方式间的差异不显著。尽管各施肥处理施用的氮、磷、钾数量完全相等 ,但土壤微生物生物量碳、氮、磷的含量却因肥料种类的不同而异。综合 0～ 5和 5～ 1 0cm土层 ,微生物生物量碳、磷为 :猪粪 +化肥 >秸秆 +化肥 >绿肥 +化肥 >化肥 >不施肥 ,微生物生物量氮则为 :猪粪 +化肥 >绿肥 +化肥 >秸秆 +化肥 >化肥 >不施肥。相关分析结果显示 ,土壤微生物生物量碳、氮与土壤有机碳、土壤全氮和土壤碱解氮之间均呈极显著的正相关 ,表明其与土壤肥力关系密切 。

长期不同施肥对甘蔗产量稳定性、肥料贡献率及养分流失的影响

【目的】分析长期不同施肥对甘蔗产量稳定性、肥料贡献率及氮磷养分地表径流流失的影响,明确其对甘蔗产量、肥料利用及环境效应,为南方赤红壤蔗区合理施肥,维持甘蔗高产、稳产及降低环境污染,改善农田生态系统质量提供依据。【方法】以长期肥料径流定位监测试验为基础,选取不施肥(CK)、推荐施肥(OPT)、过量施氮(OPT+N)、过量施磷(OPT+P)4个处理,分析甘蔗蔗茎8年产量变化、肥料贡献率及氮磷地表径流流失量。【结果】在种植的前4年,CK处理甘蔗蔗茎产量急剧下降,之后保持在50 t·hm-2并趋于平衡。施肥处理不同年份间波动性较大,但在相同年份内波动较小。与CK相比,施肥显著提高甘蔗蔗茎产量和稳定性,8年平均,蔗茎产量施肥处理增幅均高达70%以上。施肥处理下,蔗茎产量OPT与OPT+P处理差异不显著,但显著高于OPT+N处理。蔗茎产量稳定性三者间均差异不显著。蔗地地力贡献率在试验前4年急剧下降,肥料贡献率急剧上升。之后,两者均基本稳定在50%左右。肥料贡献率及肥料农学利用率OPT处理均显著高于或相当于OPT+N和OPT+P处理。施肥显著提高氮磷养分地表径流流失量。过量施入氮磷肥显著增加相应氮磷流失量,但对氮(磷)肥径流流失率无显著影响。【结论】长期过量施入氮磷化肥不仅没有增产、稳产优势,还造成养分流失。推荐施肥是南方赤红壤蔗区兼顾甘蔗高产稳产、高肥料贡献率及低养分流失的较好施肥模式。