农用矿物的特点及应用机理分析

农用矿物是指经简单加工后可直接用于农业生产的矿物,它主要用于制造天然肥料、土壤改良剂、复混肥、饲料添加剂、农药、菌肥载体、作物生长调节剂等。本文着重从肥料、土壤改良、饲料生产三方面对农业矿物的特点和应用机理进行了分析和探讨。１天然肥料矿物资源作为农用...     

设施蔬菜测土配方施肥有关问题初探

阐述了设施蔬菜测土配方施肥的特殊性,介绍设施蔬菜的营养需求和施肥特征,针对天津市目前设施蔬菜施肥及测土配方施肥存在问题,提出了设施蔬菜测土配方施肥的基本原则、对策和措施。     

韶关土壤重金属污染状况

随着工矿业的迅猛发展，韶关土壤重金属污染日益严重，直接影响到农作物的安全生产。笔者对韶关土壤重金属污染来源及其现状作了概述，并针对污染状况及其当地农作物生产的特点提出了一些治理和修复建议。     

成都地区典型土壤与农作物中砷含量研究

成都地区土壤和农作物中砷污染研究资料不多，本文以成都地区7类典型土壤和该土壤上生长的10余种常见农作物中的砷含量为研究对象，通过对监测数据的整理、分析，应用正态分布、方差分析、线性相关检验等方法对土壤和农作物中砷的分布规律以及两者的关系进行了比较详尽的分析和研究，并对比了国内相关研究结果，说明了成都地区土壤和农作物中砷污染的规律和相关性。     

测土配方施肥对农业面源污染氮防控效果研究

根据第一次全国污染源普查取得的成果之一,“农业源污染物排放对水环境的影响较大,农业源是总氮、总磷排放的主要来源”,笔者认为,要从根本上解决我国水的污染问题,必须防控好农业源中的氮、磷肥施用量。为此,结合我站正在实施农业部、财政部测土配方施肥补贴项目,为验证测土配方施肥对农业源氮污染物的防控效果,开展了农业源水稻施氮调控试验,探索水稻不同施氮量对农业源污染物氮的防控效果。本试验结果表明：在水稻施氮177kg·hm^-2,氮肥利用率最高,达35．79％;与农民习惯施氮相比,减少地下水排放含氮量5．6mg·L^-1,说明测土配方施肥对农业源氮污染物有较好的防控效果。     

成都平原农用土壤重金属污染现状及防治对策

随着工业化进程的加快和农业生产中化肥和农药不合理施用使得农用土壤重金属污染风险逐渐增大。本文对成都平原农用土壤和农作物重金属污染现状进行了综述，发现农用土壤和蔬菜中重金属污染均以Pb、Cd和Hg三种元素为主。分析了重金属离子在土壤一植物系统中迁移的一般规律及其影响因子，分析了农用土壤重金属污染的主要原因，为预防和防治污染提供了一些建议。     

重庆市大足县生态环境质量建设成效

大足生态农业县经过13年的建设，生态环境质量改善明显，通过对大足县大气、水质、农田土壤和农作物（水稻，小麦）的监测分析可知，污染程度都有比较明显的改善，特别是重金属在土壤和农作物中的含量有着显著的降低。     

非金属矿物和工业岩石在肥料中的应用与发展

非金属矿物和工业岩石在农用肥料中应用效果显著,它不仅可以提高农作物产量,改善农作物产品品质,还可以起到改良土壤、保水保肥和防止土地结块作用。随着试验、研究工作的不断深入,这一新型矿质肥料的开发应用正表现出许多新的发展趋势,研究其增产机理并结合农业地质背景的分析来应用这一新型矿质肥料则前景更为广阔。     

不同农艺措施对黑麦草修复土壤中Cd的影响

以黑麦草为研究对象，通过盆栽试验模拟施用有机肥、秸秆还田、间作3种农艺措施对黑麦草修复cd污染土壤的修复效果。结果表明，在土壤中加入一定比例牛粪可提高黑麦草对cd的吸收效率，非根际土中cd含量由14．56mg·k^-1降低至14．11mg·kg^-1，同时根际土中Cd含量由6．75mg·kg。提高至13．33mg·kg^-1，黑麦草体内吸附cd的含量也有一定程度的增加；在土壤中加入一定比例秸秆可促进cd向根际土壤的迁移，非根际土中cd含量由14．56mg·kg^-1降低至13．27mg·kg^-1，根际土中cd含量由6．75mg·kg^-1增加至13．46mg·kg^-1，且土壤与秸秆以5：2的比例混合时效果更明显；黑麦草与小麦间作处理根际土中cd含量显著增加，由6．75mg·kg^-1提高至14．77mg·kg^-1，同时黑麦草体内cd含量有大幅度降低。说明土壤中加入一定比例的牛粪、秸秆均可提高黑麦草吸收土壤中cd的能力，提高黑麦草对cd污染土壤的修复效率；小麦间作能抑制黑麦草对土壤中cd的吸收。     

防止农药污染土壤的措施

随着农业生产的发展,农药的用量日益增大。它们虽在防治农作物病、虫、草,促进农业增产中起到了积极的作用,但进入土壤后的有害物质超过土壤的“自净能力”,就会使土壤原来的性状逐渐变坏、从而影响农、牧业产品的产量和质量。因此,应注意农药污染土壤,做到:     

Nitrogen fertilizer recommendations for corn grown on soils amended with oily food waste

Soil and plant indices of soil fertility status have traditionally been developed using conventional soil and crop management practices. Data on managing N fertilizer for corn (Zea mays L.) produced on soils amended with C-rich organic materials, such as oily food waste (OFW) is scarce. Identification of a reliable method for making N fertilizer recommendations under these conditions is imperative. The objective of this research was to evaluate soil NO(3)-N (0- to 30-cm depth) at preplant and presidedress (PSNT) times of sampling for predicting N requirements for corn grown on fields receiving OFW. Experiments were conducted at two locations in Ontario, Canada over 3 yr (1995-1997) where OFW was applied at different rates (0, 10, and 20 Mg ha(-1)), times (fall and spring), and slope positions (upper, mid, and lower) within the same field. Presidedress soil NO(3)-N contents were higher compared with preplant time of sampling under all OFW management conditions. Corn grain yields were significantly affected by OFW management and N fertilizer application rates. Maximum economic rate of N application (MERN) varied depending on OFW management conditions. Presidedress soil NO(3)-N contents had a higher inverse relationship with MERN (r = -0.88) compared with soil NO(3)-N at preplant (r = -0.74) time of sampling. A linear regression model (Y = 180.1 - 8.22 NO(3)-N at PSNT) is proposed for making N fertilizer recommendations to corn grown on soils amended with OFW in this geographical region.     

不同有机物料还田对土壤结构与玉米光合速率的影响

为解决由于长期不合理耕作及有机物料利用率低而导致土壤养分贫瘠和土壤物理性状恶化情况,本试验针对黑土宜板结和肥力保持等问题设置了不同技术措施,研究在玉米生育时期不同有机物料还田模式对土壤结构特性及玉米光合速率的影响。结果表明：收获后浅翻深松＋秸秆还田和有机肥处理较常规处理,土壤容重下降了0.13 g＆#183;cm-3和0.09 g＆#183;cm-3,浅翻深松＋秸秆还田、有机肥、翻压绿肥和生物肥均能降低土壤紧实度,改善土壤三相比,增加土壤通气透水性,使得土壤物理结构得到改善。有机肥、秸秆还田和生物肥处理提高玉米喇叭口期光合速率,较常规处理提高2.1～7.6μmol＆#183;m-2＆#183;s-1;秸秆还田和生物肥较常规施肥处理,蒸腾速率下降57%和56%;在玉米喇叭口期各处理气孔导度均小于对照,灌浆期秸秆还田处理较常规处理气孔导度增加,导致叶片胞间CO2浓度下降,说明气孔阻力的降低导致叶片胞间CO2浓度降低。有机物料还田后可以降低土壤容重、紧实度,土壤三项比达到合理范围,并且可以提高作物的光合速率,降低蒸腾速率,尤其是秸秆还田和有机肥处理好于其他处理。保护性耕作和有机物料还田对于提高土壤肥力、改善土壤物理特性,提高作物光合速率,增加作物产量均起到积极促进作用。     

盘锦地区稻田田面水氮素动态变化及化学氮肥投入阈值研究

以水稻为供试作物,水稻土为供试土壤,采用田间定位试验的方法,以施肥后田面水中的总氮（TN）、NH4^＋-N和NO3^--N浓度为指标,进行了施氮后田面水中氮素释放规律研究。结果表明,施肥后田面水中的总氮（TN）、NH4＋-N和NO3--N浓度随着施肥量的增加而增加,随着时间的推移三者的浓度呈先上升后下降的趋势,一周后趋于稳定;以氮素表观盈余率和植株吸氮量为指标,从环境安全角度研究水稻生产化学氮肥投入阈值,初步确定试验区环境安全化学氮肥投入阈值为189.22～218.98 kg·hm^-2;以水稻产量为指标,进行了粮食安全氮肥投入阈值研究,初步确定试验区水稻生产粮食安全化学氮肥投入阈值为202.24～288.89 kg·hm^-2。综合考虑粮食安全和环境安全,试验区化学氮肥投入阈值为202.24～218.98 kg·hm^-2。     

Long-term effects of sustained beef feedlot manure application on soil nutrients, corn silage yield, and nutrient uptake

A field study was initiated in 1992 to investigate the long-term impacts of beef feedlot manure application (composted and uncomposted) on nutrient accumulation and movement in soil, corn silage yield, and nutrient uptake. Two application strategies were compared: providing the annual crop nitrogen (N) requirement (N-based rate) or crop phosphorus (P) removal (P-based rate), as well as a comparison to inorganic fertilizer. Additionally, effects of a winter cover crop were evaluated. Irrigated corn (Zea mays L.) was produced annually from 1993 through 2002. Average silage yield and crop nutrient removal were highest with N-based manure treatments, intermediate with P-based manure treatments, and least with inorganic N fertilizer. Use of a winter cover crop resulted in silage yield reductions in four of ten years, most likely due to soil moisture depletion in the spring by the cover crop. However, the cover crop did significantly reduce NO3-N accumulation in the shallow vadose zone, particularly in latter years of the study. The composted manure N-based treatment resulted in significantly greater soil profile NO3-N concentration and higher soil P concentration near the soil surface. The accounting procedure used to calculate N-based treatment application rates resulted in acceptable soil profile NO3-N concentrations over the short term. While repeated annual manure application to supply the total crop N requirement may be acceptable for this soil for several years, sustained application over many years carries the risk of unacceptable soil P concentrations.     

The myth of nitrogen fertilization for soil carbon sequestration

Intensive use of N fertilizers in modern agriculture is motivated by the economic value of high grain yields and is generally perceived to sequester soil organic C by increasing the input of crop residues. This perception is at odds with a century of soil organic C data reported herein for the Morrow Plots, the world's oldest experimental site under continuous corn (Zea mays L.). After 40 to 50 yr of synthetic fertilization that exceeded grain N removal by 60 to 190%, a net decline occurred in soil C despite increasingly massive residue C incorporation, the decline being more extensive for a corn-soybean (Glycine max L. Merr.) or corn-oats (Avena sativa L.)-hay rotation than for continuous corn and of greater intensity for the profile (0-46 cm) than the surface soil. These findings implicate fertilizer N in promoting the decomposition of crop residues and soil organic matter and are consistent with data from numerous cropping experiments involving synthetic N fertilization in the USA Corn Belt and elsewhere, although not with the interpretation usually provided. There are important implications for soil C sequestration because the yield-based input of fertilizer N has commonly exceeded grain N removal for corn production on fertile soils since the 1960s. To mitigate the ongoing consequences of soil deterioration, atmospheric CO(2) enrichment, and NO(3)(-) pollution of ground and surface waters, N fertilization should be managed by site-specific assessment of soil N availability. Current fertilizer N management practices, if combined with corn stover removal for bioenergy production, exacerbate soil C loss.     

Effect of bioremediation on the growth of Okro (<Emphasis Type="Italic">Abelmoshus esculetus</Emphasis>) in the Niger Delta soils

This paper communicates the effect of bioremediation on the performance of Okro plant (Abelmoshus esculentus) in a typical Niger Delta soil that has received 5% crude oil pollution level. Biodegrading bacteria such as Pseudomonas fluorescen, Acinetobacteria iwofii, Bacillus subtilus, Arthrobacter globiformis that was isolated from previously polluted soils was introduced into the samples. The treatment combinations are as follows (A) = control without crude oil; B = soil + crude oil, (C) = soil + crude oil + microbes, (D) = soil + crude oil + microbes, (E) = soil + crude oil + microbes + fertilizer (F) soil + microbes and (G) = soil + fertilizer. The treatment (E) gave the highest number of leaves, % crop emergence, plant biomass, microbial population and degradation of petroleum hydrocarbon compared to any of the treatments that had received crude oil. This suggested that fertilizer application does not only stimulate microbial growth but it provides the plant with more available nutrients required for plant growth.     

Estimating plant-available nitrogen release from manures, composts, and specialty products

Recent adoption of national rules for organic crop production have stimulated greater interest in meeting crop N needs using manures, composts, and other organic materials. This study was designed to provide data to support Extension recommendations for organic amendments. Specifically, our objectives were to (i) measure decomposition and N released from fresh and composted amendments and (ii) evaluate the performance of the model DECOMPOSITION, a relatively simple N mineralization/immobilization model, as a predictor of N availability. Amendment samples were aerobically incubated in moist soil in the laboratory at 22 degrees C for 70 d to determine decomposition and plant-available nitrogen (PAN) (n = 44), and they were applied preplant to a sweet corn crop to determine PAN via fertilizer N equivalency (n = 37). Well-composted materials (n = 14) had a single decomposition rate, averaging 0.003 d(-1). For uncomposted materials, decomposition was rapid (>0.01 d(-1)) for the first 10 to 30 d. The laboratory incubation and the full-season PAN determination in the field gave similar estimates of PAN across amendments. The linear regression equation for lab PAN vs. field PAN had a slope not different from one and a y-intercept not different than zero. Much of the PAN released from amendments was recovered in the first 30 d. Field and laboratory measurements of PAN were strongly related to PAN estimated by DECOMPOSITION (r(2) > 0.7). Modeled PAN values were typically higher than observed PAN, particularly for amendments exhibiting high initial NH(4)-N concentrations or rapid decomposition. Based on our findings, we recommend that guidance publications for manure and compost utilization include short-term (28-d) decomposition and PAN estimates that can be useful to both modelers and growers.     

Net global warming potential and greenhouse gas intensity in irrigated cropping systems in northeastern Colorado

The impact of management on global warming potential (GWP), crop production, and greenhouse gas intensity (GHGI) in irrigated agriculture is not well documented. A no-till (NT) cropping systems study initiated in 1999 to evaluate soil organic carbon (SOC) sequestration potential in irrigated agriculture was used in this study to make trace gas flux measurements for 3 yr to facilitate a complete greenhouse gas accounting of GWP and GHGI. Fluxes of CO2, CH4, and N2O were measured using static, vented chambers, one to three times per week, year round, from April 2002 through October 2004 within conventional-till continuous corn (CT-CC) and NT continuous corn (NT-CC) plots and in NT corn-soybean rotation (NT-CB) plots. Nitrogen fertilizer rates ranged from 0 to 224 kg N ha(-1). Methane fluxes were small and did not differ between tillage systems. Nitrous oxide fluxes increased linearly with increasing N fertilizer rate each year, but emission rates varied with years. Carbon dioxide efflux was higher in CT compared to NT in 2002 but was not different by tillage in 2003 or 2004. Based on soil respiration and residue C inputs, NT soils were net sinks of GWP when adequate fertilizer was added to maintain crop production. The CT soils were smaller net sinks for GWP than NT soils. The determinant for the net GWP relationship was a balance between soil respiration and N2O emissions. Based on soil C sequestration, only NT soils were net sinks for GWP. Both estimates of GWP and GHGI indicate that when appropriate crop production levels are achieved, net CO2 emissions are reduced. The results suggest that economic viability and environmental conservation can be achieved by minimizing tillage and utilizing appropriate levels of fertilizer.     

合理施肥与农业的可持续性发展初探

合理施肥可以提高作物产量和品质,降低农业生产成本,增加农民收入,减少环境污染;但是,在我国农业发展过程中,农民施用化肥时存在化肥的过量施用、化肥的错误选用以及化肥施用方法不科学等问题;不合理施肥引发了水污染、大气污染和土壤污染。从农业可持续性发展的角度,提出了根据作物性质选择合适肥料,测定土壤性质,根据土壤性质选择合适的肥料,采取科学的方法施肥等建议。     

Improved understanding of hyperaccumulation yields commercial phytoextraction and phytomining technologies

This paper reviews progress in phytoextraction of soil elements and illustrates the key role of hyperaccumulator plant species in useful phytoextraction technologies. Much research has focused on elements which are not practically phytoextracted (Pb); on addition of chelating agents which cause unacceptable contaminant leaching and are cost prohibitive; and on plant species which offer no useful phytoextraction capability (e.g., Brassica juncea Czern). Nickel phytoextraction by Alyssum hyperaccumulator species, which have been developed into a commercial phytomining technology, is discussed in more detail. Nickel is ultimately accumulated in vacuoles of leaf epidermal cells which prevents metal toxicity and provides defense against some insect predators and plant diseases. Constitutive up-regulation of trans-membrane element transporters appears to be the key process that allows these plants to achieve hyperaccumulation. Cadmium phytoextraction is needed for rice soils contaminated by mine wastes and smelter emissions with 100-fold more soil Zn than Cd. Although many plant species can accumulate high levels of Cd in the absence of Zn, when Cd/Zn>100, only Thlaspi caerulescens from southern France has demonstrated the ability to phytoextract useful amounts of Cd. Production of element-enriched biomass with value as ore or fertilizer or improved food (Se) or feed supplement may offset costs of phytoextraction crop production. Transgenic phytoextraction plants have been achieved for Hg, but not for other elements. Although several researchers have been attempting to clone all genes required for effective hyperaccumulation of several elements, success appears years away; such demonstrations will be needed to prove we have identified all necessary processes in hyperaccumulation.