石灰施用对酸性土壤养分状况和甘蔗生长的影响

土壤pH低,酸化严重是湛江蔗区甘蔗生产的产要限制因子之一。为了提高甘蔗产量,改善酸性 土壤障碍因素,采用土壤培养试验与甘蔗盆栽试验相结合,研究了施用石灰对酸性土壤养分状况和甘 蔗产量、糖分的影响。土壤培养试验结果表明：石灰施用量与供试酸性土壤pH、氮、钙、镁、硫、硅等有效 含量呈显著正相关,而与铁、锰的有效性呈显著负相关,说明通过合理施用石灰,可以显著提高土壤pH 和改善土壤各有效养分状况,从而提高酸性土壤生产力。桶栽试验结果也表明：在湛江蔗区强酸性土 壤上,合理施用石灰可以提高甘蔗产量和糖分,当每千克土壤施用石灰1.2 g,甘蔗产量和糖分分别比对 照提高14.2%和2.4%,当石灰施用过多,单位石灰增施量对蔗茎产量和糖分表现出负效。     

不同改良剂对元胡-水稻轮作酸化土壤改良效果研究

探究不同改良剂对元胡-水稻轮作下酸化农田土壤的改良效果。以元胡-水稻轮作为研究对象,设置元胡单季施用改良剂和元胡-水稻两季均施用改良剂处理下,分析作物收获后土壤化学性状和作物产量经济效益。结果表明：石灰、钙镁磷肥、酸性土壤调理剂在两季作物上连续施用,提升土壤pH、交换性钙、两季作物产量的效果高于在元胡单季施用;连续施用钙镁磷肥和酸性土壤调理剂能补充土壤钾素、提高土壤交换性镁含量;连续施用钙镁磷肥还能显著增加土壤有效磷和两季作物纯效益。综合来看,在元胡-水稻轮作酸化农田土壤改良生产实践中,推荐在元胡季施用1500 kg/hm²、水稻季施用 750 kg/hm²钙镁磷肥,以获得良好的改良效果和经济效益。     

生物炭对强酸性茶园土壤酸度的改良效果研究

利用盆栽试验研究了施用石灰和不同用量生物炭对强酸性茶园土壤酸度的调控效果。结果表明：施用生物炭和石灰处理均可显著提高茶园土壤pH值。5~20 g/kg生物炭施用量处理土壤的pH值低于施用石灰处理,但当生物炭用量大于40 g/kg时土壤pH值显著高于石灰处理,说明在强酸性条件下,低用量生物炭处理在调节土壤pH值的效果不如石灰。施用生物炭处理土壤阳离子交换量比施用石灰处理提高了0.98%~8.67%,盐基饱和度提高0.85%~40.90%,土壤交换性钙、镁、钾和钠含量分别提高1.70%~11.36%、32.79%~80.52%、76.47%~1744.12%和4.93%~57.48%,说明施用生物黑炭比施用石灰可增强土壤对酸的缓冲性能。     

高寒山区作物施用锌肥效果及施用方法

近几年,氮、磷化肥施用水平日益提高,土壤对作物所需锌素的供应能力相应降低,特别是石灰比和酸性沙质缺锌土壤。导致作物锌素养分供应不足,影响作物产量。1988年5月～10月,对油菜施用硫酸锌(ZnSo_4·7H_2O)进行了试验;1989年3月～11月,对玉米施用硫酸锌(ZnSo_4·7H_2O)进行了试验。以观察     

石灰施用对酸性土壤矿物结合有机碳形成的影响

为了解石灰施用对酸性土壤矿物结合有机碳的影响并促进酸性土壤的碳固定,本研究整合已发表的相关研究并在室内设置培养试验探究石灰添加调控酸性红壤矿物结合有机碳形成的可能机制。结果表明：大部分已发表的研究发现石灰添加可以显著促进酸性土壤中矿物结合有机碳的形成。室内控制试验发现石灰添加显著促进了秸秆分解转化为微生物生物量碳,这很可能是石灰促进矿物结合碳形成的主要机制之一。室内控制试验还发现石灰添加增加了钙键结合碳的含量,但是降低了铁铝结合碳的含量。综上可知,石灰添加有利于作物秸秆在酸性土壤中被微生物分解转化为矿物结合有机碳,但可能会导致不同化学键结合碳的相对含量发生变化。     

不同土壤改良剂对南方酸性土壤的改良效果研究

针对南方土壤酸性的问题,通过盆栽试验,选用了8种土壤改良剂并以此作为改土措施,研究了不同土壤改良剂对高粱生长特性、土壤物理性状和化学性状的影响,根据高粱、土壤和改良剂之间的相互作用,探讨了改良剂的作用机制,揭示了酸性土壤在改良剂作用下各项性能的变化规律。结果表明,XP2、脱硫灰改良剂和有机肥对高粱生长有较好的作用。酸性土壤施用腐植酸、腐植酸+石灰、XP2、有机肥和脱硫灰改良剂,分别较对照土壤容重有不同程度的下降;石灰、XP1、市售改良剂分别较对照土壤容重有不同程度的增加。经Duncan多重比较,除石灰处理外,其余施用改良剂的处理与不施改良剂（对照）之间的差异达到显著水平（P<0.05）。XP1处理和含有石灰的处理土壤pH较对照处理有较大幅度的提升,达到2个单位左右,差异呈显著水平（P＜0.05）。施用改良剂还可有效缓解酸性土壤铝毒的危害,红壤、赤红壤石灰处理分别比对照降低了18.0%、18.7%,XP1处理降低了16.4%、16.0%。     

农用石灰在酸性及镉污染稻田中试效果

在往年正规试验的基础上开展本次简比中间试验,以进一步验证在酸性及镉污染稻田施用石灰对调酸改土、水稻增产和降低稻谷镉量的效果。中试结果显示：在供试稻田土壤pH 5.64情况下,施用石灰平均750 kg/hm²能提升土壤pH 0.153个单位。施用石灰3000 kg/hm²比未施用石灰平均增产稻谷1529.98 kg/hm²,增产率14.74%,t检验达极显著水平。施用石灰3000 kg/hm²比未施用石灰平均增收1738.15元/hm²。增产的主要原因是促进了水稻长势和分蘖,增加了每蔸谷重。中试结果显示,施用石灰3000 kg/hm²比未施用石灰可降低稻谷镉量0.21 mg/kg,降低率37.8%,t检验达极显著水平。中试再次表明,在酸性及镉污染稻田中施用石灰对调酸改土、增产增收和降低稻谷镉量都具有良好效果,可以因地制宜加以科学推广应用。     

长期不同施肥对农田土壤养分与微生物群落结构的影响

为了阐明长期不同施肥对土壤养分与微生物群落的影响及影响机理,以杭嘉湖平原典型稻麦轮作区长期定位施肥试验土壤为对象,采用磷脂脂肪酸(Phospholipid fatty acid, PLFA)分析方法,研究了施用化肥(NPK)、秸秆(Straw)、栏肥(Manure)、化肥与秸秆配施(S+NPK)、化肥与栏肥配施(M+NPK)5种不同施肥方式对土壤主要养分指标与微生物量及微生物群落结构的影响,试验以不施肥处理为对照。结果表明,所有施肥处理均提高了土壤有机碳,其中秸秆与化肥配施、栏肥无论是单独施用还是与化肥配施所提高的有机碳含量均达到显著水平;施用化肥、有机肥、秸秆+化肥及有机肥+化肥均可在一定程度增加土壤氮、磷、钾养分。施用秸秆和栏肥显著提高了土壤中总PLFA、细菌、真菌、放线菌等含量以及微生物群落Shannon指数(P＜0.05),但施用化肥可引起土壤微生物量和多样性指数的下降。相关分析结果表明,土壤微生物PLFA含量及Shannon指数与土壤碳氮比呈显著正相关(P＜0.05)。典范对应分析结果表明,土壤有机碳含量(F=2.18,P=0.027)是影响微生物群落结构的主要环境因子。可得出结论,长期秸秆还田或施用栏肥可显著提高土壤微生物量并改变其群落结构,土壤有机碳含量及碳氮比对于土壤质量和肥力的提高具有至关重要的作用。     

甘薯缺锌及防治措施

通过对甘薯缺锌原因、症状、测试诊断及防治措施的分析研究，为甘薯高产提供技术支撑。１缺锌原因作物的矿物养分供给不仅取决于土壤中这种养分的总含量，而且也取决于在任何时候都以有效形式存在的养分总量的比例。一般酸性土壤含锌量较低，而碱性土壤因其锌元素溶解度降低，有效锌也低。而且全部养分中通常只有一小部分可被吸收，所以均会出现缺锌现象。由于提高土壤pH值能降低其锌元素的可溶性，因此，对含锌量低的酸性土壤施石灰便会导致缺锌。另外施用含铜元素肥料或是大量施磷肥，也可以加剧缺锌。２缺锌症状甘薯缺锌的主要症状是其…     

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尿素施用小技巧尿素是酰胺态氮肥,施入土壤后除少部分直接被作物吸收利用外,大部分是在土壤中脲酶的作用下转化成碳酸铵再供作物吸收;碳酸铵的化学性质很不稳定,容易分解释放出氨。尿素施在地表,也会引起氨的挥发;如果施在石灰性土壤或碱性土壤     

Analysis of Water Supply of Plants Under Saline Soil Conditions and Conclusions for Research on Crop Salt Tolerance

Abstract In the dry areas of the world there is an increasing pressure to apply low quality brackish waters for plant irrigation (agriculture, horticulture, landscape greening). Consequently there is a demand to improve salt tolerance of conventional crops and to develop adequate irrigation techniques too. The efforts in the past decades to approach the understanding of salt stress mechanism by focusing on biochemical and physiological research were disappointing with respect to progress for crop growth and yields under saline soil conditions. However, it is generally agreed by all disciplines involved in research for crop salt tolerance that under saline soils conditions the reduced water supply of crops is the most critical growth factor. The paper presents some model calculations and field investigations that demonstrate the effect of root water uptake on the salinity of the root surrounding soil fraction (rhizospheric soil). It is shown that root hair length and rhizospheric soil volumes are factors most relevant for understanding crop salt tolerance, when growing in soils. It is postulated that short root hairs contribute to a lower salt tolerance (onions), whereas long root hairs enhance water uptake from saline soils and crop salt tolerance (rape). As interactions between roots and soil contribute to the salt tolerance of crops under field conditions, it is doubtful that selection for salt tolerant varieties and breeding for salt tolerance under conditions of water and flow culture experiments is very efficient. Breeding for more salt-tolerant crops and brackish irrigation techniques should consider root morphology and soil/root contact zone.     

钢渣对辽宁地区水稻土壤镉素吸收的影响

硅素肥料降低重金属毒性和减少重金属在植物体内积累的研究报道尚不多见。因此,开展这一领域的研究工作,将为合理应用硅素肥料修复、利用被重金属污染的土壤提供重要的理论依据。试验通过对辽宁不同地区水稻土施加钢渣,来研究钢渣对土壤吸附镉的影响。试验结果表明:施用钢渣能够增加大石桥、辽中、抚顺地区土壤对镉的吸附能力,而对盘锦、康平、苏家屯地区吸附能力影响不大;土壤对镉的等温吸附曲线,符合Langmuir等温吸附方程和Frendlich等温吸附方程,且加入钢渣前后,最大吸附量和吸附常数在不同程度上发生变化。     

长期施肥对菜地土壤氮磷钾养分积累的影响

以皖北地区菜地土壤为供试土壤,以其相邻粮田为对照,研究了菜地土壤氮磷钾含量变化及其分布特征,结果表明:经过长时间种植蔬菜,菜地土壤氮磷钾养分发生了不同变化,与一般粮田相比,菜地土壤铵态氮含量没有发生明显变化,而菜地土壤硝态氮含量明显增加,菜地土壤0￣60cm土层中硝态氮含量一般为相邻粮田土壤的3￣20倍;菜地土壤磷素积累特别明显,主要积累于0￣40cm土层中,菜地土壤全磷积累量为粮田的1￣5倍,有效磷积累量为粮田的7￣20倍;菜地耕层土壤速效钾含量也明显高于粮田土壤,为粮田土壤的0.6￣4倍左右。种植蔬菜时间越长,土壤养分积累量越高。     

不同改良剂对塑料大棚土壤理化性质及甜瓜品质的影响

土壤质量退化已成为制约现代设施农业可持续发展的瓶颈,采取适宜措施开展设施土壤改良活动对于促进设施农业持续健康发展具有重要意义。该研究以西安市塑料大棚土壤改良研究为例,分别探讨了土香香(T1)、腐殖酸(T2)、富活素(T3)、蚯蚓粪(T4) 4种改良剂处理对大棚土壤基本理化性质、盐分离子组成、作物产量及品质的影响。结果表明：（1）所有改良剂处理较CK均能在一定程度上降低塑料大棚土壤容重,提高土壤孔隙度,并小幅调节土壤pH使其更接近中性。其中T1和T4处理对土壤容重和孔隙度的改良效果更好一些,T3处理后的土壤pH更接近7.00。（2）所有改良剂处理较CK均能大幅显著降低土壤盐分离子总量和电导率,尤以T3处理的效果最为明显,土壤盐分离子总量和电导率降幅可分别达到68.21%和75.89%。（3）与CK相比,不同改良剂均具有增产效果,尤以T3和T4处理的增产效果最佳,产量增幅分别达到14.37%和21.01%。（4）与CK相比,所有改良剂处理均能显著提高甜瓜的可溶性固形物,其中T3处理的效果最佳;所有处理间甜瓜可滴定酸无显著性差异;甜瓜固酸比和维生素含量有升有降,其中T1和T3处理甜瓜的固酸比较高,而T3处理甜瓜的维生素含量显著高于其他处理,达到146.21 mg/kg。总体而言,就改土、降盐、提质、增产等综合效果来看,T3处理,即施用富活素改良剂的效果最佳。     

Effect of insecticide-tolerant and plant growth-promoting Mesorhizobium on the performance of chickpea grown in insecticide stressed alluvial soils

An experiment was carried out to determine the plant growth-promoting activities of fipronil- and pyriproxyfen-tolerant Mesorhizobium isolates in the presence and absence of insecticides. The bioremediation and plant growth-promoting potentials of Mesorhizobium isolate (MRC4) was assessed using chickpea as a test crop grown under fipronil- and pyriproxyfen-stressed soils. In this study, the most promising mesorhizobial isolate (MRC4) tolerated fipronil and pyriproxyfen up to a concentration of 1600 μg ml^?1 and 1400 μg ml^?1, respectively. Isolate MRC4 produced a substantial amount of indole acetic acid (44.3 μg ml^?1), salicylic acid (35 μg ml^?1), 2,3 di-hydroxybenzoic acid (19 μg ml^?1), and exo-polysaccharides (21 μg ml^?1) in the absence of insecticides. The plant growth-promoting substances displayed by the isolate MRC4 declined progressively with increasing concentrations of each insecticide. The insecticide tolerant isolate MRC4 was further tested for its effect on chickpea plants grown in fipronil- and pyriproxyfen-treated soils. The insecticide-tolerant isolate MRC4 increased the dry matter accumulation progressively. A maximum increase of 80 (at 600 μg kg^?1 soil of fipronil) and 118% (at 3900 μg kg^?1 soil of pyriproxyfen) was recorded 135 days after sowing when compared to noninoculated plants treated with the same rates of each insecticide. Moreover, Mesorhizobium isolate MRC4 when used in fipronil- and pyriproxyfen-treated soil also increased symbiotic properties (nodulation and leghaemoglobin content), root N, shoot N, root P, shoot P, seed yield, and seed protein compared to the un-inoculated but treated solely with insecticide. The present finding suggests that the mesorhizobial isolate endowed with multiple properties could be used to facilitate the productivity of chickpea under insecticidestressed soils.     

Diallel analysis of acid soil tolerant and susceptible maize inbred lines for grain yield under acid and non-acid soil conditions

Maize is not inherently tolerant to soil acidity but due to the ever increasing demand for the crop in the developing world, production of maize on acid soils continues to expand. Breeding for maize acid soil tolerance is the best strategy to improve yield under these conditions. Therefore, the current study was done to determine the general combining ability (GCA) of eight acid-soil tolerant and susceptible inbred lines and the specific combining ability (SCA) of cross combinations of these lines for grain yield under acid and non-acid soils. The eight lines were crossed using a diallel mating design to produce 28 single cross hybrids for evaluation under acid and non-acid soils at four sites for two seasons. Line C2 was the best general combiner under both soil environments while A2/C1 and A1/C2 had the highest desirable SCA effects under optimal conditions. Loss in grain yield and sensitivity to low pH stress was higher among genotypes in light textured soils than heavy soils. Non-additive gene action was more important than additive gene action in conditioning grain yield under both environments. Results revealed that it was feasible to improve grain yield under low pH and optimum soils from the set of genotypes used in the current study.     

低分子量有机酸对土壤无机磷形态转化的影响

采用无机磷分级方法研究了有机酸对石灰性土壤和红壤无机磷形态转化的影响,结果表明,有机酸对石灰性土壤和红壤无机磷形态有明显的影响。石灰性土壤经柠檬酸和草酸浸提后,其Ｃａ２－Ｐ、Ｃａ８－Ｐ和Ｏ－Ｐ的含量增加;而Ｃａ１０－Ｐ、Ｆｅ－Ｐ和Ａｌ－Ｐ的含量下降。柠檬酸手酒石酸对红壤无机磷的形态也产生明显影响,表现为Ａｌ－Ｐ含量增加,Ｆｅ－Ｐ和Ｃａ－Ｐ含量下降,Ｏ－Ｐ变化不大。有机酸通过影响土壤中无机磷组分,促     

不同时期施用土壤改良剂对河灌区苏打盐碱地土壤及青贮玉米生长的影响

为明确盐碱地改良剂不同时期施用对河灌区盐碱地土壤的改良效果以及对青贮玉米生长的影响,采用田间试验方法,以青贮玉米‘瑞德2号’为供试作物,研究了河灌区重度苏打盐碱地国产DS、脱硫石膏、脱硫石膏配合DS 3种改良剂的秋季施用和春季施用对青贮玉米出苗率和鲜草产量的影响,分析了土壤(0~20 cm)pH、EC和碱化度的变化。结果表明：与对照（不施用改良剂）相比,施用改良剂处理的青贮玉米出苗率提高6.8%~72.7%,鲜草产量增加1223.2~28144.8 kg/hm2;土壤pH下降0.09~0.83,EC增加0.13~1.26 mS/cm,碱化度降低1.6%~19.8%;秋施和春施脱硫石膏、脱硫石膏配合DS均显著提高了青贮玉米的出苗率与鲜草产量。由此得出,3种盐碱地改良剂秋季施用效果均优于春季施用,其中以脱硫石膏配合DS的秋季施用效果最好。     

晋南石灰性土壤钾素变化及小麦施钾效果

晋南石灰性土壤钾素动态研究表明：潮土、褐土土壤速效钾含量均呈下降趋势，其中潮土下降３１．２５ｍｇ／ｋｇ，褐土下降１５．７５ｍｇ／ｋｇ。土壤质地类型、农业生态区及种植制度不同，土壤速效钾含量下降不同。小麦钾肥试验结果表明：亩施Ｋ２ＳＯ４５～２０ｋｇ，产量增加５２．９～１１１．５ｋｇ／亩，净增收益３２．７～６２．６元／亩。同时获得了小麦最高产量施肥量和经济最佳施肥量     

Seed quality of soya bean based on mineral composition of seeds of 45 varieties grown in a Brazilian Savanna acid soil

Summary The Brazilian Savannas (Cerrados), a vast area covering one fourth of the country's territory, has acidic soils that are devoid of nutrients and must be amended before cultivation. Mineral disorder on the soya bean crop has been frequent, mainly due to unbalanced liming and fertilization. There is no information on varietal differences and the impact of these practices on the seed quality. Chemical analyses were performed to assess the levels of elements in seed samples of 45 soya bean varieties from an experiment in a partly- and fully-limed acid soil. The levels of phosphorus, potassium, iron, aluminium, manganese, zinc and copper were inversely proportional to the level of liming. Calcium, magnesium, sodium, molybdenum and titanium did not show statistical differences for seed accumulation in the liming levels. There was a high frequency of varieties derived from Al-intolerant parents to increased levels of P, K, Ca and Mg, contrasting with respective lower levels in the leaves. The varietal differences suggest further investigation on the genetics of mineral element accumulation in the soya bean seeds. Aluminium levels varied between 8.7 to 5.5 mg/kg, respectively, for the partly- and the fully-limed soil, indicating that cultivation of soya beans in these acid soils produced little effect on the quality of seeds.