土壤供肥量的动态结构探讨

土壤供肥量是耕作土壤重要的肥力参数之一,也是测土配方施肥所需的五大参数之一。土壤供肥量具有动态结构,有一定的弹性范围,具有不同的特征值。不同的特征值对应着不同的施肥配方,各自的准确程度也不同。要降低配方误差,应该采用缺素区代替不施肥区产量来估算施肥量,并且采用合适的目标产量。     

土壤养分与春小麦产量关系及最佳施肥量研究

土壤养分与春小麦产量关系及最佳施肥量研究结果表明 ,春小麦产量与土壤养分关系十分密切 ,尤其与土壤有机质、碱解氮含量相关性较好 ,而与速效磷和速效钾关系较差 ;土壤养分供N量严重不足、部分缺P但富K ,这与产量 养分敏感性分析结论相一致 ;春小麦最佳施N量较常规减少 10 % ,施P量减少 15 %。     

不同施肥模式对赤红壤旱地作物产量和土壤肥力的影响

采用长期定位田间试验,研究不同施肥模式对赤红壤旱地花生一甘薯轮作制产量和土壤肥力的影响.5年定位试验表明,平衡施肥平均产量最高,花生和甘薯比常规施肥增产13.1％～13.5％,净增收提高14.0％;氮磷钾对花生和甘薯的增产率逐年提高,但花生和甘薯分别对缺磷和缺钾较敏感.年际间产量变化趋势表明,常规施肥对花生和甘薯产量的变异系数大于平衡施肥;不施肥区和氮磷钾缺素区的产量均呈现逐年下降,但缺氮对花生产量的敏感性大于甘薯,甘薯缺磷或缺钾对产量的敏感性高于花生.平衡施肥的氮磷钾利用率平均分别为40.9％、17.7％和24.2％;缺素区的土壤供肥量比不施肥区提高了近1倍;土壤有机质都有所提高,施用氮肥都使土壤酸度有所增加;不施肥区和氮磷钾缺素区都使相应的土壤速效养分明显下降;常规施肥使土壤有效磷下降22.5％,碱解氮和速效钾则基本维持不变,但平衡施肥使土壤有效磷含量基本不变,碱解氮和速效钾则分别提高26.2％和38.4％.     

甘肃中部地区水砂田玉米土壤养分丰缺指标研究

采用"3414"完全试验设计,对甘肃中部地区水砂田玉米土壤养分丰缺指标和推荐施肥指标进行了研究,因地制宜选择最优施肥方案。通过比较分析历年来土壤普查结果,得出当地水砂田玉米土壤养分的变化趋势;通过对不同肥力水平下土壤速效养分与缺素区相对产量及氮、磷、钾最佳施肥量的趋势拟合,分别导出了函数模型,划定土壤养分丰缺区间,进而演算出丰缺指标和推荐施肥指标。当地水砂田玉米土壤养分的变化趋势为:1983年以来,碱解氮、有效磷均呈逐渐提高趋势,速效钾在整个过程中则总体处于明显下降趋势。从丰缺指标可以看出:当地水砂田土壤氮素养分缺乏,磷素中度较缺,而钾素养分相对较为丰富,玉米要实现高产,既要合理增施氮、磷肥,且应根据土壤钾素丰缺状况适当补施钾肥。     

长期定位施肥对潮土微生物活性和小麦养分吸收的影响

利用中国科学院封丘农业生态实验站农田生态系统养分平衡长期定位试验地,研究长期不同施肥对土壤微生物区系、土壤呼吸强度以及小麦养分吸收的影响。结果表明,施有机肥或无机肥均有利于提高土壤细菌和放线菌数量,且有机肥优于无机肥、平衡施肥优于缺素施肥,但只有施有机肥处理显著提高土壤真菌数量。此外,施有机肥也显著提高土壤呼吸强度,有机无机配施、NPK平衡施肥、NP、PK等处理效果次之,缺P施肥(NK处理)效果最差,但施有机肥或有机无机配施均会显著降低微生物个体的CO2呼吸强度。不同施肥处理小麦幼苗对养分N、P、K的吸收累积存在显著差异,其中施有机肥处理小麦对N、P、K的吸收较为均衡,而无机肥因为所供化学养分的速效性而更易于被小麦幼苗高水平吸收;与NPK平衡施肥处理相比,缺素(N、P或K)施肥均直接导致小麦植株体内相应养分的明显亏缺,且缺N施肥(PK处理)还同时制约了小麦对K素的吸收。     

基于空间分析的河南省小麦施肥问题诊断与地理优化

基于河南小麦主产区82个县2 277个样点的"不施肥、习惯施肥、推荐施肥"对照试验数据,在绘制小麦产量图、施肥量图、土壤养分图、肥料农学效率图基础上,采用地图对比法揭示了该区域氮磷钾分配的主要问题;采用随机森林法分析了土壤养分、施肥量、地理要素(气候和土壤类型)对小麦产量变异的影响力;综合对照试验数据和多源文献,确定该区适宜的小麦氮磷钾施用范围,并按"以产定肥"、"因土施肥"原则进行施肥量地理优化。结果表明:该区农民习惯施氮、磷量普遍偏大,钾用量局部不足;推荐方案中氮、磷用量未明显降低,而钾普遍增加。两类施肥方式的共同问题是氮磷钾用量与小麦产量、土壤养分的空间匹配性欠佳。小麦产量变异的主导因素是土壤和气候资源的地理差异,施肥的影响次之,土壤养分的影响最低;小麦增产量变异同时受地理因素和施肥因素的影响,而与土壤养分丰缺无关;施肥水平高是土壤养分丰缺与小麦产量关系较弱的主要原因。根据小麦产量和土壤养分丰缺,确定氮磷钾优化施用量变化范围分别为120～210 kg·hm–2、45～105 kg·hm–2和45～120 kg·hm–2;按区域总量计,氮磷钾优化施用量较地方专家推荐量分别节约14.2%、40.0%和39.5%,较农民习惯用量分别节约20.9%、41.1%和17.5%。     

泰宁县水稻土壤氮、磷、钾丰缺指标初步研究

为摸清水稻土壤养分丰缺状况,2009年在泰宁九个乡镇进行了水稻"3414"施肥效应试验,获得了缺素区水稻的相对产量。采集各试验点土壤样品进行养分含量分析,获得了大量土壤养分数据。根据水稻相对产量和土壤养分数据,建立了水稻氮、磷、钾丰缺指标体系。该研究成果可以用来指导当地水稻施肥。     

泰宁县水稻土壤氮、磷、钾丰缺指标初步研究

为摸清水稻土壤养分丰缺状况,2009年在泰宁九个乡镇进行了水稻"3414"施肥效应试验,获得了缺素区水稻的相对产量。采集各试验点土壤样品进行养分含量分析,获得了大量土壤养分数据。根据水稻相对产量和土壤养分数据,建立了水稻氮、磷、钾丰缺指标体系。该研究成果可以用来指导当地水稻施肥。     

玉米生育特性及推荐施肥技术要点

玉米在生长发育过程中需要吸收大量营养元素,其中氮、磷、钾三元素需求量最多,其次是钙、镁、硫、硼、锌、硅等元素。玉米的施肥原则是:施足基肥、轻施苗肥、重施拨节肥、巧施粒肥。基于此,通过分析玉米生育特性和需肥规律,对氮、磷、钾、锌按土壤养分含量和作物目标产量需要量进行玉米推荐施肥,土壤本身供肥能力较强,对应的最佳施肥量减少,反之,施肥量增加。     

不同施肥处理对水稻养分吸收和稻田土壤微生物生态特性的影响

在水稻长期定位肥料试验条件下研究了不同施肥处理对水稻养分吸收动态变化和土壤微生物生态特性的影响。该长期定位试验设有CK(不施肥对照)和PK、NK、NP、NPK五个肥料处理和常规稻、杂交稻品种对比处理。研究结果表明,水稻产量分别与水稻吸氮总量、吸磷总量和吸钾总量显著相关;在连续种植水稻条件下,水稻对所缺养分的吸收量呈逐年下降趋势,表明缺肥区土壤相应的有效养分库消耗很快。土壤微生物特性测定表明,不平衡施肥降低了土壤微生物量N,使微生物量C/N比增加。与缺肥区相比较,NPK配施处理促进了土壤微生物的功能多样性,同时增加了土壤微生物总量。可见,土壤中养分不足或供应不平衡,不仅影响水稻养分的吸收,而且对土壤微生物总量和群落多样性产生重要影响。     

不同肥料配合施用土壤有机碳盈亏分布

几种施肥处理的田间试验结果表明：连续四年不施肥，土壤有机碳亏缺主要来自松结态有机无机复合体及缩合程度较低的腐殖质。因此，四年间土壤供肥能力明显降低。仅施化肥保持高产，土壤有机磷亏缺不多，亏损主要来自稳结态和紧结态腐殖质，由于残体“自然归还”的补偿，松结态碳尚有盈余，因此，对土壤复合体和供肥性能的不良影响较轻。有机肥与化肥配合施用，土壤有机碳均呈盈余平衡。土粪与化肥配合，盈余碳几乎在松结态与稳结态及     

Effects of mulch location on banana weevil,soil and plant nutrients,soil water and biomass in banana fields

Major constraints to banana (Musa spp., genome group AAA) production, a dietary staple for over 70 million people in sub-Saharan Africa, are pest infestations, poor nutrition and inadequate water. Although mulch can improve soil water and nutrient status, many farmers believe it also promotes the proliferation of banana weevil (Cosmopolites sordidus), one of the most serious banana pests. In this study, we evaluated the effects of mulch location (mulch to base of banana pseudostem; mulch recessed 1 m from the pseudostem) on banana weevil, soil and plant nutrient status, soil water, and banana growth and development. After 3 years, the fully mulched plots had significantly more soil Ca and Mg than plots that did not receive mulch. Banana foliar K concentration was significantly higher in both mulch treatments (full and recessed) than in the control (no mulch) plots. The mulched plots had greater recharge after rainfall events and higher soil water contents during dry periods due to increased infiltration in the mulched plots. However, the mulched plots also exhibited significantly higher banana weevil densities and greater plant damage than the control plots. There was no difference in weevil damage with mulch location, although weevil density was higher in the fully mulched plots throughout most of the trial. Despite greater weevil damage, the treatments that were mulched yielded significantly heavier bunches. Hence the effects of the mulch on soil water infiltration and banana foliar nutrient status outweighed the detrimental effects of banana weevil damage.     

Effects of the annual invasive plant Impatiens glandulifera on the Collembola and Acari communities in a deciduous forest

Invasive plants can disturb interactions between soil organisms and native plants and thereby alter ecosystem functions and/or reduce local biodiversity. Collembola and Acari are the most abundant microarthropods in the leaf litter and soil playing a key role in the decomposition of organic material and nutrient cycling. We designed a field experiment to examine the potential effects of the annual invasive plant Impatiens glandulifera on species diversity, abundance and community composition of Collembola and Acari in leaf litter and soil in a deciduous forest in Switzerland. Leaf litter and soil samples were obtained from plots invaded by I. glandulifera since 6 years, from plots in which the invasive plant had been removed for 4 years and from plots which were not yet colonized by the invasive plant. The 45 leaf litter and soil samples were equally distributed over three forest areas, which were differently affected by a wind throw 12 years prior to sampling representing a natural gradient of disturbance. Collembola species richness and abundance in the leaf litter and soil samples were not affected by the presence of the invasive plant. However, the species composition of Collembola was altered in plots with I. glandulifera. The abundance of leaf-litter dwelling Acari was increased in invaded plots compared to the two other plot types. Furthermore, the presence of the invasive plant shifted the composition of Acari individuals belonging to different groups. Our field experiment demonstrates that an annual invasive plant can affect microarthropods which are important for nutrient cycling in various ecosystems.     

等高植物篱控制紫色土坡耕地侵蚀的特点

应用等高植物篱能在较低投入下有效控制坡地土壤侵蚀和养分流失。三峡库区紫色土 2 5°坡地的大雨强模拟降雨实验表明 ,香根草等高植物篱能减少相当于对照坡耕地的 82 .2 %的侵蚀量 ( 1 997年 1 1月 ) ,通过施肥促进植物篱生长密闭能进一步提高对流失土壤的拦截效率 ,效果不逊于带间覆盖。经过 31个月的侵蚀过程 ,各植物篱小区最明显的坡形变化是篱带处及其前部堆淤成接近水平的淤积带。由于植物篱的阻滞和坡形的变缓 ,径流和表土作用的时间延长 ,由径流携带的养分损失成为坡面养分流失的重要途径 ,控制径流损失是控制养分流失的重要方式之一 ,同时也有助于减少坡面侵蚀     

Wild boar and red deer affect soil nutrients and soil biota in steep oak stands of the Eifel

In sloping oak forests of the German low mountain range high wild boar (Sus scrofa) and red deer (Cervus elaphus) population densities may affect soil ecological processes by grubbing, grazing, trampling and dunging. We simulated wild boar grubbing in a fenced exclosure and an unfenced replicate and established two adjacent control plots, one fenced, the other unfenced. We evaluated if repeated soil bioturbation and game exclusion by fencing influence soil texture, soil chemical and soil biotic properties in the upper soil over a time period of 2 years. Soil bioturbation was conducted in November 2000 and 2001 creating a grubbing pattern similar to that found in naturally grubbed areas. Soil and fauna sampling was performed in spring and fall of the years 2001 and 2002.Soil bioturbation did not affect soil texture, pH and the contents of organic carbon and nitrogen. In contrast, the contents of potassium and magnesium, the microbial activity and the abundance of saprophageous and predatory soil arthropods were generally lower in grubbed plots compared to ungrubbed control plots (p≤0.05).The exclusion of game did not improve soil quality. On the contrary, microbial activity and the contents of organic carbon and total nitrogen were elevated outside the fenced exclosure (p≤0.05) which may be related to the deposition of urine and dung.Our study found that large mammals affect soil nutrient cycling in sloping oak forests either directly by the deposition of urine and dung or indirectly by accelerating nutrient leaching and disturbing the decomposer system in the soils.     

不同养分条件下太子参根部土壤环境变化及综合评价

研究不同养分条件下太子参根部土壤环境变化的时间动态,探索太子参根部土壤环境的综合评价方法,可为指导太子参高效栽培提供理论基础。于3个不同土壤养分地块上分别种植太子参,定期监测其根部土壤化学性质、土壤酶活性及微生物种群结构变化,用主成分分析进行综合评价。结果表明：太子参整个生长时期,不同土壤养分条件下太子参根部土壤均以全磷、缓效钾、有效磷、速效钾含量以及土壤酸性转化酶（S-AI）和土壤过氧化氢酶（S-CAT）活性变异度最大;有机质及氮素含量、土壤酸性磷酸酶（S-ACP）、土壤脲酶（S-UE）及土壤多酚氧化酶（S-PPO）活性变异度较小;太子参成熟后,细菌和放线菌菌群数量显著增加,真菌菌群数量显著减少。测定的16个土壤环境指标中较多指标间显著相关,出现信息重叠,影响评价结果的客观性;以基本特征值大于1抽取5个成分,利用5个成分函数表达式进行综合评分,结果得出,各土壤养分含量越高,综合得分值越大,土壤环境越优。上述结果说明：太子参生育期内磷、钾素变化较大,及时补足磷、钾肥可能是改善太子参根部土壤环境的有效方法之一。利用主成分综合评分方法能客观、高效评价太子参根部土壤环境情况。     

Long-term conservation tillage results in a more balanced soil microbiological activity and higher nutrient supply capacity

Soil health depletion due to intensive tillage operations is a global issue in the agricultural sector. Conservation tillage (CT) which involves non-inversion tillage and leaving ∼30% of the soil surface covered with crop residues, is a strategy designed to enhance soil health. However, no comprehensive study to investigate the long-term effect of CT on soil biological activity and the soil nutrient supply has yet been widely carried out. Biological and chemical soil properties were assessed at depths 0–5, 10–15, and 20–25 cm depths after 18 years of CT and conventional tillage practice (PT). Various stages in the vegetative growth of maize were investigated in 2021 in Hungary. The findings indicated that tillage intensity, soil depth, and growth stages all significantly influenced soil enzyme activities and the concentration of soil nutrients. Less soil disturbance resulted in a significantly larger concentration of soil carbon parameters (total organic carbon and labile carbon) in CT plots, where the activity of β-glucosidase and dehydrogenase (DHA) in the upper soil layer increased significantly (0.7–2.6 and 2.6–4.7 times, respectively) compared to PT. The high amount of organic matter and the greater resistance to erosion observed in CT also contributed to the higher concentration of available nutrients (NH₄, NO₃, Ca, K) and total P in the surface soil layer. Phosphatase activity was highest in the mid-stage of vegetative growth and was positively correlated to the total P concentration. The alterations in soil water content were clearly negatively correlated with the change in DHA and phosphatase activity. Overall, due to the more balanced environmental conditions, the decomposition of organic substances was more balanced and slower in CT than in PT. This implied that the mobilization of nutrients in the soil was more balanced as well, and that the nutrients were released gradually. The enhancement of the soil nutrient-supplying capacity achieved by means of long-term conservation tillage provides a promising strategy for sustainable nutrient management.     

Soil erosion and participatory remediation strategy for bench terraces in northern Thailand

This study was carried out in Pang Prarachatan village, which is located in Chiang Rai province of northern Thailand. The farmers in this village construct bench terraces to reduce soil erosion and increase plant productivity. However, severe soil erosion occurs frequently on the bare bench terraces. This study investigates the impact of bench terracing on soil erosion. The use of weeds and plant residues to control soil and nutrient losses were also investigated using model slope plots and an artificial rainfall system. Finally, the knowledge gained from this study was transferred to the farmers through a workshop in the village, and their acceptance of the results was evaluated by means of a questionnaire. The severity of soil erosion is thought to vary according to the structure of the bench terrace and the ground cover conditions. Rills are the primary form of erosion on bare bench terraces. In addition, some rills develop into gullies that can run from the upper terrace down to the lower terrace. Nevertheless, rills and gullies are rarely found on weed-covered terraces. Moreover, the results of an erosion experiment using model slope plots and artificial rainfall systems showed that plots covered with weeds and plant residues had much less surface runoff and soil and nutrient losses than bare soil. The amounts of nitrogen and phosphorus absorbed by weeds were 4.7 and 2.3 times smaller than the nitrogen and phosphorus losses due to soil erosion, respectively. The results of the field surveys and model slope experiment were announced to the farmers through participatory workshop in August 2003. The first questionnaire, conducted just after the workshop, clearly showed that around 90% of the farmers agreed to cover their slopes with weeds and plant residues so long as it did not affect soil fertility and plant growth. However, the second questionnaire, conducted in January 2004, showed that only 29% of farmers were covering the bench terraces or non-terraced slopes in their farmlands with weeds and plant residues. Therefore, participatory activities should continue to be held regularly in order to ensure greater acceptance and practice of soil conservation on the part of the farmers.     

EM堆肥对土壤生物影响的研究

长期定点施用EM堆肥试验结果表明:EM有机堆肥能提高土壤细菌、真菌、放线菌数量;相同有机物料投入水平下,EM堆肥处理的微生物总量最高;随着有机物料投入水平的降低,土壤微生物数量下降;施用EM能提高土壤微生物活性,增加微生物的分布密度。施用EM堆肥土壤蚯蚓数量均显著高于其他施肥处理。EM堆肥各处理平均土壤螨虫数量高,但在相同的有机物料投入水平下,差异不显著。在大部分作物生长期,施EM 15t/hm2处理与化肥处理和对照处理土壤生物总量差异显著。     

Nutrient losses in eroded sediment after fire in eucalyptus and pine forests in the wet Mediterranean environment of northern Portugal

Nutrients sorbed onto eroded sediment from small bounded plots installed in newly burned and unburned Eucalyptus globulus and Pinus pinaster forests in the Águeda Basin, north-central Portugal were measured over an 18-month period. The data are used to determine: (i) the effects of fire on nutrient loss, (ii) the importance of fire-induced losses on soil fertility, and (iii) temporal variations in nutrient losses. Fire increased losses of total nitrogen, exchangeable potassium and available phosphorus by 3–4 orders of magnitude. This is attributed to increased erosion and high nutrient concentrations at the soil surface in the burned forests, where burning of organic matter and vegetation increased nutrient availability. Enhanced rates of loss were sustained for at least 3 years, resulting in much greater post-fire nutrient losses than reported in drier regions of the Mediterranean. Losses of available P had the greatest potential for reductions in soil fertility.