三种植物物料对两种茶园土壤酸度的改良效果

用室内培养实验研究了稻草、花生秸秆和紫云英在 5、10 和 20 g/kg 的加入量水平下对茶园黄棕壤和茶园红壤酸度的改良效果.结果表明:除了黄棕壤加入紫云英处理会降低土壤的 pH 外,其余所有加入植物物料的处理均使土壤 pH 有不同程度的增加,使土壤交换性酸和交换性Al的数量减小,使土壤交换性盐基阳离子和盐基饱和度增加.有机物料对土壤酸度的改良效果与有机物料灰化碱和N含量有关,灰化碱和有机N的矿化使土壤 pH 升高,NH4+-N的硝化使土壤 pH 降低.3种植物物料中花生秸秆对土壤酸度的改良效果优于紫云英和稻草.加入植物物料使红壤中有毒形态Al的浓度显著减小,说明植物物料能够缓解红壤中Al对植物的毒害.     

通过调节土壤氮素转化提高有机物料对红壤酸度的改良效果

通过培养试验,比较研究了油菜秸秆、稻草、香樟叶和豌豆秸秆单独施用以及油菜秸秆、稻草和香樟叶与豌豆秸秆混合施用对红壤酸度的改良效果。结果表明,在60天培养期内,添加4种物料均提高了土壤pH。培养试验结束时香樟叶、油菜秸秆、豌豆秸秆和稻草分别使土壤pH相对对照增加0.53、0.42、0.30和0.26。对于灰化碱含量很高的非豆科物料如香樟,其对土壤酸度的改良效果主要来源于物料所含碱性物质和物料对土壤硝化反应的抑制,但对灰化碱含量较低的非豆科物料如油菜秸秆和稻草,其改良效果主要来源于后者。豆科类豌豆秸秆主要通过所含碱性物质和有机氮矿化提高土壤pH,但培养试验后期铵态氮硝化反应释放的质子抵消了其部分改良效果。将油菜秸秆、稻草和香樟叶与豌豆秸秆配合施用,使硝化反应受到一定程度的抑制,提高了物料对土壤酸度的改良效果。培养试验结束时,香樟叶、稻草和油菜秸秆与豌豆秸秆配合施用比豌豆秸秆单独施用土壤pH分别高0.25、0.18和0.12。研究发现,香樟叶灰化碱含量很高,无论单独施用,还是与豌豆秸秆配合施用均有很好的改良效果,因此在南方地区推广种植香樟可以通过其凋落物修复酸化的森林土壤。     

土壤加速酸化的主要农业驱动因素研究进展

土壤酸化是土壤质量退化的一个重要方面,农业活动对其有极其重要的驱动作用。本文从土壤酸化加速的农业主驱因素:化肥、作物及有机物料等方面阐述它们对土壤酸化的影响。认为化肥尤其是生理酸性肥料和含硫肥料的不合理施用加速土壤酸化,而氮肥的致酸除受氮素形态影响外,硝化作用及硝化产物的淋溶是重要的致酸原因,同时豆科作物的固氮致酸作用也不容忽视。作物通过选择性吸收盐基阳离子,通过秸秆和子粒转移出生产系统后,导致土壤盐基量减少,土壤表面交换性酸增加;作物根系呼吸、根系分泌物及土壤溶液中重碳酸盐的淋溶也引起土壤酸化;而秸秆和畜禽粪便对土壤酸化的影响除受土壤本身性质影响外,秸秆中的灰化碱含量、畜禽粪便中的碳及氮和盐分去向对酸化也有重要的影响。     

长期施用化肥和秸秆对活性有机质组分的影响

以长期定位试验为基础,分析了长期施用化肥和秸秆对土壤不同组分C、N的影响.结果表明:连续施肥16年后,与CK处理相比,单施化肥使土壤全N、有机C、轻组有机N、颗粒态有机N、碱解N、易氧化有机C分别增加了13.8%,9.4%,38.2%,20.0%,19.7%和26.3%,但并没有增加轻组有机C量和颗粒态有机C量.化肥与秸秆配施后,土壤全N、有机C和不同组分C、N含量都显著大于单施化肥.单施化肥显著降低了土壤有机质、轻组有机质、颗粒态有机质的C/N比,但化肥与秸秆配施后, 其C/N比并没有继续降低.此外,易氧化有机C量与土壤有机C量显著相关,颗粒态有机N量、轻组有机N量、碱解N和土壤全N间也存在显著相关性.     

秸秆还田对吉林黑土区土壤有机碳、氮的影响

秸秆是农业生产的重要有机肥来源之一,研究其还田过程中土壤有机碳、氮的变化,对了解土壤质量的改变具有重要意义。2011年5～9月作物生长期间,对黑土区不同秸秆全部还田、秸秆全部还田+化肥(C:N=1:10)、秸秆全部还田+化肥(C:N=1:20)后,土壤有机碳、氮的变化研究结果显示,与秸秆未还田(对照)相比,秸秆全部还田(C1.0)条件下土壤pH与土壤湿度略有降低,其他指标则相应增加;含有秸秆的处理中,土壤有机碳、pH、土壤呼吸强度、土壤温度变化趋势均为C1.0>C/N10>C/N20。土壤呼吸强度、土壤温度、湿度变化随着时间呈下降趋势。主成分分析显示,秸秆还田有利于改善土壤有机碳、全氮以及C/N等。     

长期施肥条件下黑土有机碳和氮的动态变化

以黑土地区海伦农田生态系统国家野外科学观测研究站的农田长期(1990～2004年)肥料定位试验土壤为试验材料,对不同施肥处理有机碳和氮进行了系统分析。结果表明,长期不施化肥(CK),土壤中有机碳、全氮、碱解氮及C/N呈现下降趋势;长期施用氮肥,土壤有机碳亏损速率较大,但土壤氮素变化较小,C/N保持相对稳定;长期施用磷肥,土壤有机碳含量下降速率较小,但全氮含量下降速率较大,因而C/N保持上升趋势;长期施用钾肥,土壤有机碳、氮及C/N变化趋势相同,但土壤有机碳含量下降速率较小,C/N增加较快。因此,通过调控化肥可以维持土壤的有机碳、全氮及碱解氮含量,保持土壤的持续生产力及提高作物产量。     

不同有机物料及其配施对潮棕壤轻组有机碳的动态影响

用埋袋法研究了潮棕壤中加入单一物料(玉米秸秆,稻草秸秆,苜蓿,鸡粪,猪粪)和混合物料(玉米秸秆-鸡粪-猪粪和苜蓿-鸡粪-猪粪)后土壤中轻组有机碳的一年内动态变化。结果表明:施不同有机物料后,土壤中轻组有机碳与对照相比都有较大幅度提高。随着培养时间的推移,不同处理的土壤中轻组有机碳碳含量都逐渐下降,且其下降趋势与添加物料的C/N比值呈显著的正相关。相关分析表明,施用混合物料处理中轻组有机碳的含量与单一物料处理都呈显著的正相关。     

秸秆还田施氮调节碳氮比对土壤无机氮、 酶活性及作物产量的影响

秸秆的质量,特别是C/N是影响秸秆分解速率和养分释放的重要因素。在秸秆还田条件下,如何科学合理地施用氮肥是秸秆利用和优化施肥研究的关键问题。本研究以秸秆还田施入碳氮的C/N为切入点,于2012—2013年通过田间试验(设秸秆不还田不施肥、秸秆还田不施氮、秸秆还田施用无机氮肥调节C/N为10∶1、16∶1和25∶1以及秸秆还田施用有机氮肥调节C/N为25∶1处理),研究秸秆还田不同氮输入对小麦-玉米轮作田土壤无机氮、土壤微生物量氮、酶活性以及作物产量的影响。结果表明:1)在C/N为25∶1下,施用有机氮肥和无机氮肥对土壤无机氮含量无显著影响;在施用无机氮肥的情况下,C/N越低土壤无机氮含量越高。2)秸秆还田施氮提高了土壤微生物量氮含量,但是各秸秆还田施氮处理之间差异不显著;秸秆还田不同施氮处理对脲酶活性无显著影响;秸秆还田施氮提高了FDA水解酶活性,并随C/N降低呈升高趋势,施用无机氮肥的效果强于施用有机氮肥的。3)秸秆还田施用无机氮肥显著提高了小麦和玉米地上部生物量,施用无机氮肥调节C/N为10∶1和16∶1相比于C/N为25∶1提高了小麦和玉米的苗期和成熟期地上部生物量;施用有机氮肥调节C/N为25∶1相比秸秆还田不施氮对地上部生物量无显著影响。秸秆还田施用无机氮肥提高了作物产量,施用无机氮肥调节C/N为16∶1产量最高,而施用有机氮肥调节C/N为25∶1有降低作物产量的趋势。综合以上结果来看,施用无机氮肥调节C/N为16∶1较为合理。     

种植花生、施用尿素对红壤酸化作用及有机物料的改良效果

通过连续2年盆栽试验,比较研究了种植花生和施用尿素对红壤pH和交换性Al含量的影响,以及施用几种有机物料(稻草、紫云英、猪粪)对土壤酸化的改良效果,为花生种植地区合理施用有机物料缓解土壤酸化、提高产量提供参考依据。结果表明,与同一季中相同施肥处理不种花生的土壤相比,种植花生1季和2季后土壤pH分别降低了0.06～0.28和0.08～0.27,土壤交换性Al则分别增加了7.69%～72.94%和8.49%～46.20%;施用尿素增加了花生产量,但同时也加剧了土壤酸化,同一季中有机物料施用相同情况下,与低尿素水平处理的土壤相比,高尿素水平处理1季和2季后土壤pH分别下降了0.02～0.10和0.01～0.16;不同有机物料对土壤酸化的改良效果:猪粪稻草紫云英,且有机物料施用量越大,土壤pH升幅越大,土壤交换性Al含量则越低;几种有机物料中,猪粪处理显著增加了花生产量,2季中花生秸秆干重平均增加了11.12%～59.28%,花生籽粒干重平均增加了12.42%～68.20%;紫云英效果次之,稻草增产效果不明显。     

多种有机物料混施对苹果幼苗生长、氮素利用及土壤特性的影响

以"M9T337"苹果幼苗为试材,利用~(15)N同位素示踪技术,研究了等氮量投入下,不同有机物料单施及混施对苹果幼苗生长、~(15)N吸收利用及土壤特性的影响。试验设置CK(只施用化学肥料,不施有机物料)、S(秸秆)、B(生物炭)、F(牛粪)、SB(1/2秸秆+1/2生物炭)、SF(1/2秸秆+1/2牛粪)、FB(1/2牛粪+1/2生物炭)、SFB(1/3秸秆+1/3牛粪+1/3生物炭)8个处理。结果表明:施用有机物料可以促进苹果幼苗的生长,其中SFB处理植株鲜重、株高、茎粗、叶面积、根系活力达到最优,显著高于CK和单施有机物料的处理。添加有机物料能降低土壤容重、增加孔隙度、提高土壤含水量,其中施用生物炭的处理土壤容重降幅较大、孔隙度较高。处理期间,有机物料混合施用的处理土壤矿化氮含量、土壤酶活性及微生物数量均优于有机物料单独施用的处理。与CK和单施有机物料的处理相比,有机物料混合施用显著提高了苹果幼苗~(15)N利用率和土壤~(15)N残留率,降低了~(15)N损失率,其中3种有机物料混施效果最好。综合分析可知,有机物料能促进苹果幼苗生长,改良土壤性质,促进植株对~(15)N的吸收利用,其中牛粪、秸秆和生物炭混合施用的处理(SFB处理)效果最佳。研究结果以期为有机物料在苹果园土壤质量提升和化肥减施增效中的应用提供依据。     

Use of crop residues with alkaline slag to ameliorate soil acidity in an Ultisol

Information regarding the interaction between liming agents and crop residues on soil acidity amelioration is limited. A laboratory incubation study was undertaken to investigate the combined application of alkaline slag (AS, the major component is CaO) and crop residues with different C/N ratios and ash alkalinity content. Incorporation of amendments was effective in reducing soil exchangeable acidity and Al saturation and increasing exchangeable base cations (P < 0.05), but the effect of AS on soil pH adjustment was reduced when added with a high amount of residue with a low C/N ratio. Initial increases in soil pH were attributed to the release of alkalinity from the combined amendments and the mineralization of organic nitrogen (N). During subsequent incubation, the soil pH decreased because of nitrification. Crop residues with a high C/N ratio increased N immobilization and reduced net nitrification, resulting in a slight pH decrease. Crop residues with a low C/N ratio resulted in a sharp decrease in soil pH when applied with low levels of AS because of stimulated soil nitrification, whereas high AS had no consistent effect on net nitrification. Hence, compared to the control (pH = 4.21), a large increase in soil pH occurred, especially when peanut straw was applied at 10 g/kg (pH = 5.16). It is suggested that crop residues with high C/N ratio and also combined with a liming agent such as AS are preferred to ameliorate soil acidity. The liming effect of AS is likely to be negated if added in combination with residues with high N contents.     

Amelioration Effects of Crop Residues with Different Chemical Components on an Acidic Tea Garden Soil

Various crop residues were applied to a strongly acidic tea garden soil to investigate their performance in ameliorating soil acidity. A laboratory study found the performance of crop residues on soil acid amelioration was mainly determined by the combined effect of nitrogen (N) transformation, cation exchange, and ash alkalinity. Nitrogen transformation was varied for different crop residues added, but followed N regulation, resulting in an adverse liming effect. It was assumed that during the release of ash alkalinity, cations replaced soil exchangeable acidity in soil solution, which largely diminished the liming effect of ash alkalinity. That was why soil pH was highly correlated with N transformation process. Furthermore, soil pH was positively correlated with carbon (C)/N ratios of crop residues both in low-level treatment (R ² = 0.955) and in high-level treatment (R ² = 0.981). Therefore, crop residues with relative high C/N ratios were considered to be more suitable for long-term pH adjustment of tea garden soils.     

The amelioration effects of low temperature biochar generated from nine crop residues on an acidic Ultisol

Biochar was prepared using a low temperature pyrolysis method from nine plant materials including non‐leguminous straw from canola, wheat, corn, rice and rice hull and leguminous straw from soybean, peanut, faba bean and mung bean. Soil pH increased during incubation of the soil with all nine biochar samples added at 10 g/kg. The biochar from legume materials resulted in greater increases in soil pH than from non‐legume materials. The addition of biochar also increased exchangeable base cations, effective cation exchange capacity, and base saturation, whereas soil exchangeable Al and exchangeable acidity decreased as expected. The liming effects of the biochar samples on soil acidity correlated with alkalinity with a close linear correlation between soil pH and biochar alkalinity (R² = 0.95). Therefore, biochar alkalinity is a key factor in controlling the liming effect on acid soils. The incorporation of biochar from crop residues, especially from leguminous plants, can both correct soil acidity and improve soil fertility.     

复配改良剂表施对高降雨量地区茶园底层强酸性土壤酸度的调控

Strongly acidic soils (pH < 5.0) are detrimental to tea (Camellia sinensis) production and quality. Little information exists on the ability of surface amendments to ameliorate subsoil acidity in the tea garden soils. A 120-d glasshouse column leaching experiment was conducted using commonly available soil ameliorants. Alkaline slag (AS) and organic residues, pig manure (PM) and rapeseed cake (RC) differing in ash alkalinity and C/N ratio were incorporated alone and in combination into the surface (0--15 cm) of soil columns (10 cm internal diameter × 50 cm long) packed with soil from the acidic soil layer (15--30 cm) of an Ultisol (initial pH = 4.4). During the 120-d experiment, the soil columns were watered (about 127 mm over 9 applications) according to the long-term mean annual rainfall (1 143 mm) and the leachates were collected and analyzed. At the end of the experiment, soil columns were partitioned into various depths and the chemical properties of soil were measured. The PM with a higher C/N ratio increased subsoil pH, whereas the RC with a lower C/N ratio decreased subsoil pH. However, combined amendments had a greater ability to reduce subsoil acidity than either of the amendments alone. The increases in pH of the subsoil were mainly ascribed to decreased base cation concentrations and the decomposition of organic anions present in dissolved organic carbon (DOC) and immobilization of nitrate that had been leached down from the amended layer. A significant (P < 0.05) correlation between alkalinity production (reduced exchangeable acidity -- N-cycle alkalinity) and alkalinity balance (net alkalinity production -- N-cycle alkalinity) was observed at the end of the experiment. Additionally, combined amendments significantly increased (P < 0.05) subsoil cation concentrations and decreased subsoil Al saturation (P < 0.05). Combined applications of AS with organic amendments to surface soils are effective in reducing subsoil acidity in high-rainfall areas. Further investigations under field conditions and over longer timeframes are needed to fully understand their practical effectiveness in ameliorating acidity of deeper soil layers under naturally occurring leaching regimes.     

农业废弃物制备的生物质炭对红壤酸度和油菜产量的影响

利用自行研制的生物质炭化炉在田间条件下制备花生秸秆炭和油菜秸秆炭,采集秸秆气化站产生的稻壳炭,研究了这3种生物质炭对酸性土壤的改良效果和对油菜产量的影响。结果表明:施用稻壳炭、花生秸秆炭和油菜秸秆炭均可提高土壤p H,降低土壤交换性酸含量,效果随施用量的增加而增强。生物质炭对酸性土壤的改良效果主要决定于其本身的含碱量,施用花生秸秆炭和油菜秸秆炭显著增加土壤交换性盐基阳离子、有效磷、有效阳离子交换量和盐基饱和度,并提高油菜籽产量。田间条件下施用花生秸秆炭和油菜秸秆炭3年后土壤p H仍明显高于对照处理,说明生物质炭对土壤酸度的改良具有持续性。因此,花生秸秆炭和油菜秸秆炭是优良的酸性土壤改良剂。     

Amelioration of an acid ultisol by agricultural by‐products

Ultisols are widely distributed in the subtropical regions of China as well as in the world. High acidity of Ultisols limits plant growth and reduces crop yields. Amelioration of an acid Ultisol was investigated by incorporating the residues of canola (Brassica campestris L.), wheat (Triticum aestivum L.), rice (Oryza sativa), corn (Zea mays), soybean (Glycine max), peanut (Arachis hypogaea), faba bean (Vicia faba L.) and pea (Pisum sativum) and Chinese milk vetch (Astragalus sinicus L.) shoots after incubation of the agricultural by‐products for a maximum of 75 days, soil pH was increased by each of the plant materials. The degree of amelioration of the soil acidity by the plant materials was found to depend on the ash alkalinity and N content of the materials; the legumes of higher ash alkalinities and lower N contents, such as peanut straw and faba bean straw, led to the largest increases in soil pH, while the legumes of higher N contents showed less amelioration of the acidity to a certain degree, because of the release of protons during nitrification of NH from mineralisation of organic N. The non‐leguminous materials have medium amelioration effects and increased soil pH by 0·42–0·56 units at the end of incubation. The incorporation of the plant materials also increased exchangeable base status and reduced exchangeable Al, and thus decreased the toxicity of Al in the soil. This study demonstrates that plant materials, especially crop residues, can be used as amendments for acidic soils to restore degraded land in subtropical regions. Copyright © 2010 John Wiley & Sons, Ltd.     

不同产地油菜秸秆制备的生物质炭对红壤酸度和土壤pH缓冲容量的影响

  目的  明确不同产地油菜秸秆制备的生物质炭对红壤酸度的改良和土壤pH缓冲容量的提升效果。  方法  将不同添加量的油菜秸秆炭分别与两种酸性红壤混合,然后进行室内培养试验,测定培养实验前后土壤pH、pH缓冲容量、土壤交换性盐基离子和土壤交换性酸。  结果  添加油菜秸秆炭显著提高了土壤的pH、pH缓冲容量、交换性盐基离子含量,显著降低了土壤交换性酸含量。说明添加油菜秸秆炭不仅可以改良红壤酸度,还能提高红壤的抗酸化能力,因而可以减缓土壤的复酸化。生长在碱性土壤上的油菜秸秆制备的生物质炭对红壤酸度的改良效果和对土壤pH缓冲容量的提升效果均优于生长在酸性土壤上的油菜秸秆制备的生物质炭,在5%添加水平下,前者使湖南红壤pH相比对照提高37.4%,后者使该土壤的pH提高22.4%;相应地,2种生物质炭分别使该土壤的pH缓冲容量分别提高41.4%和37.3%。2种油菜秸秆炭对红壤pH和pH缓冲容量的提升效果与其碱含量和表面官能团多少相一致。  结论  碱性土壤上生长的油菜秸秆制备的生物质炭对红壤具有更好的改良效果。     

Effect of crop residue biochar on soil acidity amelioration in strongly acidic tea garden soils

Strongly acidic soil (e.g. pH < 5.0) is detrimental to tea productivity and quality. Wheat, rice and peanut biochar produced at low temperature (max 300 °C) and differing in alkalinity content were incorporated into Xuan‐cheng (Ultisol; initial pH_{soil/water = 1/2.5} 4.12) and Ying‐tan soil (Ultisol; initial pH _{soil/water = 1/2.5} 4.75) at 10 and 20 g/kg (w/w) to quantify their liming effect and evaluate their effectiveness for acidity amelioration of tea garden soils. After a 65‐day incubation at 25 °C, biochar application significantly (P < 0.05) increased soil pH and exchangeable cations and reduced Al saturation of both tea soils. Association of H⁺ ions with biochar and decarboxylation processes was likely to be the main factor neutralizing soil acidity. Further, biochar application reduced acidity production from the N cycle. Significant (P < 0.05) increases in exchangeable cations and reductions in exchangeable acidity and Al saturation were observed as the rate of biochar increased, but there were no further effects on soil pH. The lack of change in soil pH at the higher biochar rate may be due to the displacement of exchangeable acidity and the high buffering capacity of biochar, thereby retarding a further liming effect. Hence, a significant linear correlation between reduced exchangeable acidity and alkalinity balance was found in biochar‐amended soils (P < 0.05). Low‐temperature biochar of crop residues is suggested as a potential amendment to ameliorate acidic tea garden soils.