农业生产中轮作可持续性的研究进展

正近年来许多研究指出,轮作可以在增加粮食产量的基础上保持或者提高土壤有机质含量,实现可持续生产。土壤有机质是土壤中含有碳、氮的组成和结构不均的有机化合物,其是表征土壤质量的重要指标,影响着土壤中的各个生态过程,对土壤多种理化性质都有影响,其主要来源为土壤中的动植物残体和有机肥料。有机质含量丰富的土壤中营养元素不易流失、利用率较高,微生物活动旺盛,利于作物生长和环境保护。1对土壤有机质含量的影响     

马尾松对喀斯特石漠化地区土壤有机质的影响

以桂西北喀斯特地区为例,研究了石漠化生态恢复过程中,马尾松对土壤有机质含量的影响,并对坡向、海拔高度、恢复年限、植被类型等生态因子与马尾松样地土壤有机质含量的相关性进行了分析,结果表明:土壤水分含量、电导率、凋落量、纤维素分解强度等与马尾松林土壤有机质含量呈正相关,凋落物有机质含量与马尾松林土壤有机质含量呈负相关.坡向对土壤有机质含量有较明显的影响,东南坡土壤有机质含量比西北坡高;在一定范围内,植被恢复时间越长,土壤有机质含量就越高;马尾松林土壤有机质含量通常随海拔的升高而有下降的趋势.但是,喀斯特地区生态环境十分脆弱.极易受到人为因素的影响.人为干扰的频度和强度不同,土壤有机质的变化规律也不同,干扰越大,有机质含量越低,土壤就越贫瘠.     

土壤持水力与土壤有机质的关系

田间测定和模拟试验表明,土壤有机质含量越高,土壤持水力越强。土壤有机质含量与有效水最大贮量呈正相关,与土壤总孔隙度、毛管孔隙度和通气孔隙度呈显著正相关。有机质含量越高,土壤孔隙状况越好,土壤有效水含量越高。     

土壤理化性质对盐碱地水稻产量的影响

为全面掌握大荔县盐碱地土壤理化性质对水稻产量的影响,通过在大荔县盐碱地种植水稻,设置空白对照(CK),比较分析了土壤p H、电导率、有机质、全氮、有效磷及速效钾含量对水稻产量的影响。结果表明:土壤p H、电导率下降越多,水稻产量越高,土壤有机质、全氮、有效磷及速效钾含量提高越高,水稻产量越高。种植水稻可有效改善盐碱地土壤理化性质。     

桑根达来不同林龄榆树林土壤养分特征

[目的]研究正蓝旗桑根达来镇榆树林土壤养分随林龄增加的变化趋势及其规律。[方法]选择桑根达来镇3种不同林龄(10、25、40 a)榆树林为研究对象,测定了0～10、10～20、20～40 cm土层土壤pH、速效氮、速效磷、速效钾、有机质含量共5个指标。采用双因素分析法、相关性分析研究不同林龄榆树土壤养分在不同垂直深度土层中的含量特征及其相互关系。[结果]林龄对榆树根系土壤的速效氮、速效磷、速效钾含量及pH有显著或极显著影响;土层对土壤的速效磷、有机质含量及pH有显著影响;二者的协同作用对速效磷有极显著影响。随林龄增加,榆树林土壤有机质和速效氮、速效钾含量呈上升趋势;速效磷在表层及深层土壤中先降低后升高,在中层土壤中先升高后降低。随着土壤深度的加深,土壤有机质、速效氮、速效钾含量均呈现较明显的表聚现象。土壤pH随林龄增加逐渐降低,且与速效氮、速效磷、速效钾的含量呈显著负相关,土壤酸性越高,土壤养分含量越高。[结论]该研究可为该地区榆树林的养分管理、提质增效及近自然改造提供重要的理论依据。     

植烟土壤化学性质与酶活性的典型相关分析

分别在烤烟移栽后30、50、75、100 d采集根际土壤,测定土壤化学性质及酶活性,运用典型相关分析法分析两组变量的关系。结果表明:有机质与4种土壤酶均有较强的相关性,且有机质与脲酶活性有典型正相关关系,说明提高有机质的含量能够增强土壤脲酶活性;速效钾与土壤碱性磷酸酶活性呈典型负相关关系,说明速效钾含量越高,碱性磷酸酶活性越低,而有机质对其影响最小;速效磷与蔗糖酶、蛋白酶活性呈典型负相关关系。     

有机质添加对铅污染农田土生态功能稳定性的影响研究

应用磷脂脂肪酸(PLFA)分析方法,研究有机质的添加对受到不同程度铅污染的土壤中微生物群落的结构和多样性的影响,探讨土壤有机质含量与铅污染土壤稳定性的相关关系。结果表明:在受到重金属铅污染的土壤微生物群落中细菌占主导地位;土壤铅污染越严重、有机质含量越低,土壤微生物的多样性越低,反之多样性越高;革兰氏阴性菌和真菌与有机质含量和土壤稳定性呈显著正相关关系(P0.01)。可通过提高铅污染土壤中有机质含量来增强土壤的生态功能稳定性。     

滩涂互花米草生境土壤微生物特征及土壤酶研究

互花米草在沿海滩涂可有效助淤及护坡,在滩涂定植后对滩涂生态有一定的影响。对沿海滩涂互花米草生境土壤取样,分析微生物的类型、土壤酶活性,并与脱盐水稻土比较。结果表明,互花米草生境土壤地表水呈碱性,土壤中盐分含量较高,表层积累有可溶性盐,土壤中理化性状指标、土壤微生物类群、土壤酶活性三者之间有密切联系。有机质含量越高,营养成分越高,其微生物的数量越多,则纤维分解菌数量多;土壤含氮量高,则脲酶活性高,固氮菌数量多;土壤有效磷的含量越高,磷酸酶的活性越高。     

龙山植烟土壤有机质分布特征及其与主要养分的关系

为了探明龙山植烟土壤有机质分布及其对主要养分的影响,2014年对龙山县300个土壤样品有机质含量及土壤主要有效养分含量进行检测。结果表明:龙山植烟土壤有机质平均为27.15 g/kg,仍有39.00%的植烟土壤有机质含量偏低;龙山不同母质植烟土壤有机质含量由高到低依次为:洪积物(38.33 g/kg)残积物(27.71 g/kg)坡积物(26.96 g/kg);龙山植烟土壤有机质含量随海拔升高有机质呈先上升后趋于稳定的趋势,海拔837 m是土壤有机质含量的重要拐点;植烟土壤主要养分与有机质含量均呈极显著正相关关系,土壤有机质对主要养分含量的影响在23.00和29.00 g/kg附近有2个极显著的拐点。     

太仓市农田土壤有机质与全氮含量关系分析

土壤有机质含量和全氮含量是土壤肥力诸因素中很重要的2个因素。在化学测定技术上,土壤全氮的测定较繁琐,而土壤有机质的测定较为容易。通过对测定的大量数据进行回归分析,找出太仓市土壤有机质含量与全氮含量之间的关系,从而根据土壤有机质的测定结果估算土壤全氮的含量。结果表明,土壤有机质与全氮呈显著线性相关关系,回归方程为:y=0.039x+0.5。土壤有机质含量高低对土壤供氮水平有明显影响。     

石家庄地区耕地土壤有机质含量时空变异特征及提升对策

石家庄自2005年开始实施测土配方施肥技术项目,在该项目实施过程中测定了大量的土壤样本。通过对土样有机质化验数据进行分析,研究了石家庄地区耕地土壤有机质含量时空变异特征。结果表明：从时间上看,近30a来石家庄地区耕地有机质含量呈逐步上升趋势,其中中西部增长迅速、东部增长缓慢;从空间上看,中南部（高邑、栾城等）褐土类耕地有机质含量较高,东部（晋州、辛集）潮土类耕地有机质含量较低,西部和北部山区丘陵地耕地有机质含量居中;粮食高产县（市、区）耕地有机质含量较中低产县（市、区）耕地有机质含量高。通过分析耕地土壤有机质时空变异规律及影响因素,提出了今后石家庄地区耕地有机质提升的对策和建议。     

鄂伦春旗耕地土壤有机质含量的时空变化趋势及其与大豆产量的关系

为全面分析鄂伦春旗土壤有机质含量随着时间推移发生的变化及在空间上的分布情况,比较该区域不同土壤类型有机质含量的差异,探讨土壤有机质和全氮含量之间的关系,对2008-2014年在鄂伦春旗域内均匀采集的7722个耕地土壤样品进行土壤类型判别及有机质、全氮含量测定,并与1986年全国第二次土壤普查数据进行对比,同时通过盆栽试...     

阿维菌素土壤淋出液对水生植物影响作用的研究

通过室内模拟耕作层土壤。用土柱法以浮萍为指示作物研究了阿维菌素的3种不同土壤淋出液对水生植物的影响作用。结果表明：阿维菌素3种土壤淋出液均对浮萍有一定的影响作用,其中土壤有机质含量对药剂的淋溶性影响明显。在有机质含量高的土壤中,阿维茵素的淋出液对浮萍的影响较小．说明药剂在土壤中淋溶作用就越弱,即阿维菌素土壤淋出液对水生植物的影响作用与土壤的有机质含量戍负相关。     

有机无机肥料配合施用对草甸暗棕壤有机质含量及作物产量的影响

经过20年长期定位试验,研究施用不同种类肥料对草甸暗棕壤有机质含量及作物产量的影响。结果表明:长期不施肥使土壤有机质含量持续下降;长期单施NP化肥能有效缓解有机质含量下降的趋势;长期单施有机肥以及有机、无机肥料配合施用能有效地提高土壤有机质的含量。尤其是有机、无机肥料配合施用不仅能有效提高土壤有机质的含量,并且在产量上较无肥及单施肥料的处理有明显的增产效果。     

土壤酸度对大豆、油菜生长和产量的影响

 两个盆栽试验结果显示，施用石灰石粉和钙镁磷肥能显著促进大豆生长和根瘤形成，并能提高产量，施用石灰增加了大豆植株Ca含量，但减少其K含量；施用磷肥增加植株的P含量，但减少植株的Ca的含量，大豆的根瘤数和籽粒产量与土壤pH、交换性Ca和Al及铝饱和度之间呈显著相关。10年的石灰石粉长期定位试验结果表明，在施用钙镁磷肥的条件下，施用3750kg/hm#+2石灰石粉即可使油菜获得高产，但适当过量施用石灰并未使油菜减产。要使红壤油菜获得最佳产量，必须使土壤pH值提高到5.9以上,而交换性铝降至1.0cmol(+)/kg以下。     

丛枝菌根真菌对温室有机土栽培黄瓜的作用研究

研究了2种丛枝菌根真菌在有机土基质和普通土壤中对温室黄瓜生长、产量及营养品质的影响。结果表明:接种GM后黄瓜的光合速率,叶片可溶性糖都显著高于对照;接菌可显著提高黄瓜产量,在有机土中接种Glomous mosseae(GM)和Glomous versiforme(GV)可使黄瓜产量分别比对照提高28.5%和25.4%,而土壤中接种GM和GV亦可使其产量分别比对照提高58.1%和31.3%,同时接种菌根菌后瓜条中的总糖、VC、干物重均明显提高,营养品质得到明显改善。因此可以认为在黄瓜生产中应用菌根苗可以明显提高黄瓜的产量品质。     

不同施肥措施对黄泥田土壤养分及水稻产量的影响

为农业有机废弃物的合理科学利用提供参考,在湖北省孝昌县单季稻区利用田间试验研究6种施肥措施对黄泥田土壤肥力及水稻产量的影响。结果表明:不同施肥措施对黄泥田土壤有效磷与速效钾含量的影响显著,对有机质、全氮及碱解氮含量的影响不明显。在6种施肥措施中,以化肥+畜禽粪肥配施黄泥田土壤的有机质、全氮、碱解氮、有效磷和速效钾含量最高,分别为23.06 g/kg、1.34 g/kg、111.66mg/kg、30.77mg/kg和148.33mg/kg,且有效磷和速效钾含量显著高于其他施肥措施(P0.05);稻谷和稻草产量也最高,分别为9 638.38kg/hm~2和11 118.39kg/hm~2,也显著高于其他施肥措施(P0.05);水稻的综合农艺性状好。因此,在黄泥田水稻生产过程中,采用化肥和畜禽粪肥配施可有效培肥其土壤,提高水稻产量。     

有机肥对旱地春小麦的生产效应及土壤肥力的影响

经过3年的研究表明，合理施用有机肥料，不仅能提高旱地春小麦产量，获得高产和稳产，而且能有效地提高土壤肥力，增加土壤养分。只增施化肥，不施或少施有机肥，不仅春小麦产量较低，而且导致土壤养分逐渐减少，土壤有机质逐年下降，土壤板结。     

Effects of long-term full straw return on yield and potassium response in wheat-maize rotation

The effect of long-term straw return on crop yield, soil potassium(K) content, soil organic matter, and crop response to K from both straw and chemical K fertilizer(K_2SO_4) were investigated in a fixed site field experiment for winter wheat-summer maize rotation in 6 years for 12 seasons. The field experiment was located in northern part of North China Plain with a sandy soil in relatively low yield potential. Two factors, straw return and chemical K fertilizer, were studied with two levels in each factor. Field split design was employed, with two straw treatments, full straw return of previous crop(St) and no straw return, in main plots, and two chemical K fertilizer treatments, 0 and 60 kg K2 O ha~(–1), as sub-plots. The results showed that straw return significantly increased yields of winter wheat and summer maize by 16.5 and 13.2% in average, respectively, and the positive effect of straw return to crop yield showed more effective in lower yield season. Straw return significantly increased K absorption by the crops, with significant increase in straw part. In treatment with straw return, the K content in crop straw increased by 15.9 and 21.8% in wheat and maize, respectively, compared with no straw return treatment. But, straw return had little effect on K content in grain of the crops. Straw return had significant influences on total K uptake by wheat and maize plants, with an increase of 32.7 and 30.9%, respectively. There was a significant correlation between crop yield and K uptake by the plant. To produce 100 kg grain, the wheat and maize plants absorbed 3.26 and 2.24 kg K2 O, respectively. The contents of soil available K and soil organic matter were significantly affected by the straw return with an increase of 6.07 and 23.0%, respectively, compared to no straw return treatment. K_2SO_4 application in rate of 60 kg K2 O ha~(–1) showed no significant effect on wheat and maize yield, K content in crop straw, total K uptake by the crops, soil available K content, and soil organic matter. The apparent K utilization rate(percentage of applied K absorbed by the crop in the season) showed difference for wheat and maize with different K sources. In wheat season, the K utilization rate from K_2SO_4 was higher than that from straw, while in maize season, the K utilization rate from straw was higher than that from chemical fertilizer. In the whole wheat-maize rotation system, the K absorption efficiency by the two crops from straw was higher than that from K_2SO_4.     

Effects of maize-soybean relay intercropping on crop nutrient uptake and soil bacterial community

Maize-soybean relay intercropping is an effective approach to improve the crop yield and nutrient use efficiency, which is widely practiced by farmers in southwest of China. To elucidate the characteristics of different planting patterns on crop nutrient uptake, soil chemical properties, and soil bacteria community in maize-soybean relay intercropping systems, we conducted a field experiment in 2015–2016 with single factor treatments, including monoculture maize(MM), monoculture soybean(MS), maize-soybean relay intercropping(IMS), and fallow(CK). The results showed that the N uptake of maize grain increased in IMS compared with MM. Compared with MS, the yield and uptake of N, P, and K of soybean grain were increased by 25.5, 24.4, 9.6, and 22.4% in IMS, respectively, while the N and K uptakes in soybean straw were decreased in IMS. The soil total nitrogen, available phosphorus, and soil organic matter contents were significantly higher in IMS than those of the corresponding monocultures and CK. Moreover, the soil protease, soil urease, and soil nitrate reductase activities in IMS were higher than those of the corresponding monocultures and CK. The phyla Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria dominated in all treatments. Shannon's index in IMS was higher than that of the corresponding monocultures and CK. The phylum Proteobacteria proportion was positively correlated with maize soil organic matter and soybean soil total nitrogen content, respectively. These results indicated that the belowground interactions increased the crop nutrient(N and P) uptake and soil bacterial community diversity, both of which contributed to improved soil nutrient management for legume-cereal relay intercropping systems.