不同种植年限日光温室土壤盐分和养分变化研究

以山西省临汾市不同种植年限的蔬菜日光温室土壤为研究对象，分析了土壤有机质、碱解氮、硝态氮、速效磷、速效钾等养分指标的累积状况以及温室土壤电导率、可溶性盐、pH值的变化情况。结果表明，与大田土壤相比，温室土壤电导率和可溶性盐含量逐年增加，pH值下降，种植8a的日光温室土壤盐分累积量已接近黄瓜的生育障碍临界点；土壤养分均有不同程度的累积，尤其是土壤速效磷、硝态氮的累积严重；日光温室特殊的环境条件以及过量施用化肥是土壤盐分累积和养分富集的主要原因。     

西安市郊区日光温室大棚番茄施肥现状及土壤养分累积特性

调查了西安市郊区100余个日光温室栽培番茄的施肥现状,并采集了60个日光温室土壤剖面样品,测定了土壤养分及盐分含量。结果表明,当地番茄的氮磷钾化肥的平均施用量分别为N 600 kg hm-2,623 kg P2O5hm-2和497 kgK2O hm-2。过量施肥特别是过量施用磷肥比较普遍。日光温室土壤0~20 cm和20~40 cm土层有机质、有效磷、速效钾含量均明显高于露地。不同地点日光温室土壤0~100 cm土层硝态氮含量及土壤电导率存在差别,但其含量均高于露地土壤,其中日光温室土壤0~100 cm土层硝态氮含量较露地的增加幅度在127%~433%之间。由于研究地区土壤多发育在河流冲积物上,地下水位埋藏浅,土壤质地相对较粗,因此,不合理施肥引起的土壤养分累积及损失,以及由此带来的环境问题值得关注。     

甘肃省几种主要农田土壤肥力监测结果

对甘肃省几种主要耕种农田土壤肥力连续5年的定位监测结果进行分析。结果表明:农田土壤耕层有机质、全氮、速效磷均比第二次土壤普查值增加,速效钾均比普查值下降;施肥结构不合理,土壤耕层养分盈亏量为氮盈余,磷富积,钾亏缺。     

日光温室土壤养分含量及比例与种植年限的关系

对陕西省泾阳县的日光温室蔬菜施肥情况与土壤养分状况进行了研究。结果表明,泾阳县日光温室氮磷钾养分的纯投入量平均为N·651 kg hm~(-2)、P2O5·485 kg hm~(-2)和K2O·855 kg hm~(-2),养分投入量明显偏高。温室耕层土壤速效磷、速效钾、水溶性钾和水溶性钙与种植年限之间都存在极显著的线性正相关关系,相关系数分别为0.995、0.973、0.973和0.979。种植7年后,硝态氮、速效磷、速效钾的含量分别是农田土壤的1.8、5.1和3.6倍,水溶性钾、钙、镁分别是农田的12.2、4.5和2.6倍。随种植年限的延长,温室土壤K、Ca、Mg三者的比例严重失衡,由养分不合理施用带来的养分损失及可能引起的环境问题值得关注。     

甘肃省几种主要农田土壤肥力监测结果

对甘肃省几种主要耕种农田土壤肥力连续5年的定位监测结果进行分析，结果表明：农田土壤耕层有机质、全氮、速效磷均比第二次土壤普查值增加，速效钾均比普查值下降：施肥结构不合理，土壤耕层养分盈亏量为氮盈余，磷富积，钾亏缺。     

日光温室栽培对土壤养分累积及交换性养分含量和比例的影响

研究了日光温室栽培下陕西关中地区不同土壤养分累积及交换性养分含量及比例的变化,结果表明：日光温室栽培下土壤有机质、硝态氮、有效磷和速效钾等养分显著累积,土壤阳离子交换量明显增加,而土壤pH却出现下降趋势。日光温室土壤交换性K^＋含量显著增加;日光温室和大田土壤交换性Ca^2＋含量相比无明显差异,而日光温室土壤交换性Mg^2＋的含量及其离子饱和度有所提高。日光温室土壤钙饱和度、Ca/K和M g/K均明显低于大田土壤。认为日光温室栽培下大量施用钾肥,是土壤钙离子饱和度及Ca/K和M g/K比例降低的主要原因,建议在评价日光温室土壤养分有效性时,应综合考虑交换性养分的含量、饱和度及离子间的比例关系。     

河北省饶阳县土壤养分特征分析及分区施肥研究

为摸清饶阳县土壤养分特征,实现针对性分区指导施肥,采用田间试验和室内分析相结合的方法,明确了该县耕地土壤养分供应状况和分布特征。结果表明:目前饶阳全县土壤有机质、碱解氮、有效磷、速效钾平均含量分别为15.5 g/kg、77.1 mg/kg、29.1 mg/kg、108.0 mg/kg。耕层土壤有机质及大量元素在各乡镇分布差别明显,变异系数表现为有效磷速效钾碱解氮有机质。与第二次土壤普查结果比,全县土壤有机质、碱解氮、有效磷分别增加37.2%、29.1%和314.3%;而速效钾减少29.5%。结合该县多年田间试验和专家实践经验、农户调查和土壤养分分布特征,建立了小麦施肥指标体系,并编绘了针对区域养分供应特征的氮、磷、钾肥施用量图件,便于指导农民优化平衡施肥。     

半旱地不同栽培模式及施氮下农田土壤养分表观平衡状况研究

以在陕西关中地区连续7年的夏玉米冬小麦轮作体系定位试验为对象,采用养分投入量与作物养分携出表观平衡法分析了不同栽培模式及施氮量下土壤氮磷钾养分的平衡状况及其与土壤养分含量间的关系。结果表明,两种秸秆覆盖的模式（即覆草模式和垄沟模式）土壤氮磷钾养分的亏缺状况均较常规模式及控水模式低,说明秸秆还田在平衡土壤养分状况方面具有重要作用。当施氮量为每季N 120 kg/hm2时,土壤氮素基本达平衡状况;而施氮量达N 240 kg/hm2时,土壤氮素盈余量显著增加,平均达1471 kg/hm2。不同处理土壤氮平衡值与土壤 02 m剖面累积的硝态氮以及土壤磷、钾的总平衡值与土壤有效磷及速效钾间呈极显著正相关,土壤氮平衡值每增加100 kg/hm2,02 m土壤剖面硝态氮累积量增加约 38.3 kg/hm2;土壤磷、钾的平衡值每降低 100 kg/hm2,土壤有效磷和速效钾含量分别降低约 3.5 mg/kg和1.0 mg/kg,说明农田养分平衡盈亏决定了土壤养分的消长规律。     

不同使用年限蔬菜大棚土壤溶质含量变化的试验研究

在石灰性褐土上分别选取种植1、3、6、9年蔬菜的大棚土壤,旨在研究不同种植年限对土壤养分、盐分、微量元素及重金属的影响。结果表明,随着种植年限的增加,大棚土壤的养分、盐分等均显著高于对照,其年度增长率表现为有机质＜氨态氮＜全盐量＜速效钾＜硝态氮＜速效磷,其中速效磷、硝态氮、全盐量依次较对照提高21.8倍、15.9倍、2.3倍。微量元素的年度增长幅度表现为Mn＜Zn＜Cu＜Fe,其中有效态Cu、Zn、Fe含量均高于临界值。重金属年度的增长幅度表现为Pb＜Cr＜Cd,虽然Cr、Cd、Pb均未超标,但大棚土壤养分、盐分、微量元素与重金属含量均随大棚利用年限的增加呈递增趋势,须引起人们的关注。     

我国耕地土壤养分变化与肥料投入状况

根据全国耕地地力监测点 10余年监测结果 ,分析了我国耕地土壤养分变化与肥料投入状况。结果表明 ,有机肥投入量有逐渐减低的趋势 ,而化肥投入量稳中有升 ;常规施肥区土壤有机质、速效氮、速效钾年度间基本稳定 ,而速效磷稳中有升 ;空白区土壤有机质、速效氮基本稳定 ,速效磷、速效钾有下降趋势。养分收支平衡分析表明 ,氮磷盈余、钾亏缺。氮盈余量北方旱地、南方旱地和水田随年度稳中有升 ,而北方水田逐渐下降 ;磷盈余均稳中有升 ;钾亏缺南方水田在缓解 ,而其他农田在逐渐加大     

NUTRIENT UPTAKE AND USE EFFICIENCY BY TROPICAL LEGUME COVER CROPS AT VARYING PH OF AN OXISOL

Oxisols comprise large soil group in tropical America. These soils are acidic and have low fertility. Use of tropical legume cover crops in cropping systems is an important strategy to improve fertility of these soils for sustainable crop production. Data are limited on nutrient uptake and use efficiency of tropical cover crops under different acidity levels. The objective of our study was to evaluate growth and nutrient uptake parameters of sixteen tropical legume cover crops under three soil pH (5.1, 6.5, and 7.0) of an Oxisol. Shoot dry weight was influenced significantly by pH and cover crop treatments and their interactions, indicating that cover crops used had differential responses to changing soil pH levels. Overall, shoot dry weight decreased when soil pH was raised from 5.1 to 7.0, indicating acidity tolerance of cover crops. Nutrient concentration (content per unit of dry weight), uptake (concentration X dry weight), and nutrient use efficiency (dry weight of shoot per unit of nutrient uptake) varied significantly among cover crops. The variation in nutrient uptake and use efficiency among cover crop species was associated with variation in shoot dry matter production. Significant variation among crop species in dry matter production and low C/N ratios (average value of 14.25) suggest that cover crops which produced higher dry matter yield like white jack bean, gray mucuna bean, black mucuna bean, mucuna bean ana, and lablab are important choices for planting in tropical soils to recover large amount of macro and micronutrients, and to prevent such nutrient leaching in soil plant systems.     

黄土丘陵草地土壤营养元素含量迁移及分布

系统研究黄土丘陵草地土壤理化性质、草地和农地营养元素迁移与富集,以及土壤养分剖面分布特征的基础上,试验结果表明:黄绵土、灰钙土及黑垆土为黄土丘陵区主要土壤类型;（2）黑垆土与黄绵土土壤颗粒组成含量差异较大,黑垆土成壤过程有隐粘化现象;（3）黑垆土表层及深层养分含量普遍高于黄绵土;（4）土壤养分在坡面与土壤剖面呈指数分布,土壤有效N、P、K含量北坡>西南>南坡;（5）提高草地生产力,防治土壤肥力退化的根本途径是增加草地养分输入,（6）提高豆科牧草对土壤深层养分的利用,可实现“生物聚肥”效应,培肥土壤。     

Light Intensity Effects on Growth and Micronutrient Uptake by Tropical Legume Cover Crops

ABSTRACT

Cover crops are important components of a sustainable crop-production system in plantation crops such as cacao (theobroma cacao), coffee (Coffee arabica), oil palm (Elaeis Spp.), and banana (Musa Spp.). Optimal growth of cover crops in plantation agriculture is determined by adaptability of crop species, light intensity reaching their leaf canopies, and their nutrient-use efficiencies, including those of micronutrients. An experiment was conducted in a climatically controlled growth chamber to evaluate the influence of levels of light intensity on growth and micronutrient [boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn)] uptake parameters in legume cover crops. Two photosynthetic photon flux density (PPFD, 200 and 400 μmol m^?2 s^?1) light treatments were imposed on nine legume species (joint vetch (Aeschynomene americana), sunhemp (Crotalaria juncea L.), Crotalaria rchroleuca, showy crotalaria (crotalaria spectabilis), hairy indigo (Indigofera hirsute L.), lab-lab (Lablab purpureus), sesbania (Sesbania microcarpa), Brazilian stylo (Stylosanthes guianensis), and cowpea (Vigna unguiculata)). Overall, light intensity significantly affected growth, micronutrient uptake, and use-efficiency ratios; with few exceptions, interactions between cover crop species and PPFD were also significant. Such PPFD × crop species interactions show that the cover crops used in this study differed in growth and nutrient-uptake parameters under the conditions imposed. Sunhemp, cowpea, sesbania, and lab-lab species were superior in producing shoot dry weight and in nutrient accumulation compared with other species at lower as well as at higher PPFD levels. Interspecific differences in nutrient influx and transport were observed. Influx and transport of micronutrients was in the order Mn > B > Fe > Zn > Cu. Overall, growth, nutrient uptake, and use-efficiency ratios were higher at higher PPFD than at lower PPFD. Results of this study indicate that the use of proper crop species at adequate light intensities is an important component of successful cultivation of cover crops in plantation agriculture.     

陵县试区土壤速效磷、钾养分的演变浅析

本文研究了山东省陵县土壤养分定位监测试区土壤速效磷、钾养分随时间的变异。结果表明,1992～2002年10年间,耕层土壤速效磷含量呈上升趋势,增加0 33mg L-1 a-1;而土壤速效钾含量呈下降趋势,降低1 52mg L-1 a-1。土壤速效磷和速效钾养分时间变异趋势与土壤磷养分平衡处于盈余状态和钾养分平衡处于亏缺状况有关,土壤 作物系统内磷素(P)盈余平均为38 6kg hm-2 a-1,其实际平衡盈余率大大超过合理的范围,磷肥用量明显偏高,未得到合理高效利用;而钾素(K)亏缺平均为95 7kg hm-2 a-1,其实际平衡亏缺率略低于允许平衡亏缺率,若试区土壤钾素长期处于亏缺状态,会明显降低土壤供钾能力。     

上海郊区农田氮养分平衡及其对土壤速效氮含量的影响

通过对上海郊区的43块定位农田连续3年的跟踪监测分析，比较了50种作物以及5种不同轮作农田的氮养分平衡状况及其对土壤速效氮含量的影响。结果表明：（1）不同作物农田的氮养分盈余趋势为水生蔬菜类≥水果类〉旱作蔬菜≥大田作物≥草皮；不同轮作农田氮养分盈余大小表现为：菜菜轮作〉果树单作〉菜作轮作〉草皮单作〉作物轮作；（2）不同作物及不同轮作农田收获时土壤速效氮含量随土层的加深而逐渐降低，氮养分盈余多的农田土壤的速效氮含量也高；（3）不同作物以及不同轮作农田氮养分盈余与收获时土壤表层（0～30cm）的硝态氮和铵态氮含量呈正相关。     

Analysis of Foliage Phosphorus Requirements of Radiata Pine Plantations

Monitoring of foliage nutrients in forest plantations is used as a method to identify nutritional problems and recommend ameliorations. A requirement is the development of nutrient bench marks and these are usually a single concentration based on the level at which symptoms appear. The critical level is defined as 90% of optimum growth below which it is expected that growth responses to applied nutrients would be obtained. The phosphorus critical level at different ages in radiata pine has been developed showing a decline with age from 0.18% P at 2 years to 0.12% after 15 years. A typical standard level applied is 0.14% P which would underestimate young stands and overestimate older stands. Routine assessments in plantations show patterns of decline in P over time, on some soils they generally remain above the critical levels, others below, and some move into deficiency with time.     

华北冬绿肥作物二月兰的营养特征研究

二月兰可作为冬季绿肥作物引入华北地区农田种植,与春玉米等作物形成良好的粮肥复种体系,在华北地区有着广阔前景.本试验调查分析了二月兰从返青到成熟的养分含量及累积状况,结果表明,二月兰植株体的养分含量较高,盛花期其干物质氮、磷、钾含量分别为2.99％、0.42％和2.99％,且产量较高.二月兰对氮、钾的累积量大,对磷的累积量较小.盛花期二月兰的养分已累计完成了总量的86.3％～94.0％,是进行翻压的最适宜时期.二月兰的养分累积过程符合Logistic方程y=k/(1 +ae-bx),氮、磷、钾最大累积速率出现的先后顺序为磷最早、氮次之、钾最晚.     

兴电灌区主要带田养分循环与平衡研究

以兴电灌区6种主要带田种植模式为对象,采用田间实地调查,在典型地块划定小区按籽粒、秸秆和根茬三部分测重并取样分析化验的方法,研究了各模式的养分输入与输出状况及其养分循环与平衡特征。结果表明:除小麦/黄豆带田出现氮亏空外,其它5种带田种植模式的氮、磷、钾循环都是良好的,但其平衡条件是有足够的农家肥投入和有豆科作物的共生固氮。农家肥提供了总氮量4.62%~8.93%、总磷量17.34%~22.31%、总钾量72.61%~82.07%的养分;豆科作物提供了总氮量14.08%~42.45%的养分;化肥氮和磷占其养分输入总量的52.27%~76.06%和61.40%~70.91%;由降水和灌水携入的N,P,K分别占其养分输入总量的8.35%~12.04%,3.72%~7.74%和9.20%~17.48%。从施肥结构来看,6种带田种植模式的氮、磷、钾养分输入比例极不合理,在生产上应提倡"控氮、增磷"策略,同时注重化学钾肥的施用,并推行秸秆还田和高茬收割技术,以提高养分循环再利用的效率。     

Management practices of macronutrients for potato for smallholder farming system at alluvial soil (Entisols) of India

In the present study, seven fertilizer treatments [T₁, 50% NPK; T₂, 100% NPK (Recommended dose of fertilizer, 200–65.4–124.5 kg N-P-K ha^?1); T₃, 150% NPK; T₄, 100% PK; T₅, 100% NK; T₆, 100% NP and T₇, control (zero NPK)] with four replications were assessed in the new alluvial soil zone (Entisols) of West Bengal, India. The objectives of the study were to generate information on potato productivity, profitability, indigenous nutrient supply and net gain/loss of NPK in post-harvest soil. Plants grown under higher NPK supply resulted in higher tuber yield and there were significant (p ≤ 0.05) reductions in total yield with nutrient omissions. Nutrient?limited yields were 19.78, 2.83 and 1.77 t ha^?1 for N, P and K, considering total tuber yield (28.24 t ha^?1) obtained under 100% NPK as targeted yield. Indigenous nutrient supply of N, P and K were estimated at 24.1, 22.34 and 110.22 kg ha^?1, respectively that indicates higher K?supplying capacity of experimental soil as compared to N and P. Net income (US$1349 ha^?1 year^?1) and B:C ratio (1.91) was highest with 100% NPK, and further addition of NPK (150%) resulted in decrease on net return (US$1193 ha^?1 year^?1) and B:C ratio (1.73).     

25年来种植业结构调整驱动的县域养分平衡状况的变化——以山东惠民县为例

本文以山东省惠民县为例,采用1984年全国第二次土壤普查和2004年土壤调查的实测数据以及历年农户调查结果和统计数据,系统分析了过去25年来惠民县种植业结构调整对该县养分平衡和土壤养分特征的影响。结果表明,惠民县种植业结构由以粮棉为主演变为以棉粮菜为主;该县的养分平衡状况为氮盈余6089～19405t,磷盈余259～7001t,钾亏缺2532～6712t;该县土壤有机质含量、全氮含量、速效磷含量分别增加了57%、22%、303%,速效钾含量则降低了6%。种植业结构的改变影响了农田氮、磷、钾养分的投入,进而影响到整个县域的养分收支平衡和土壤的养分含量,因此如何合理进行作物种植布局并优化不同种植体系的施肥技术将成为今后区域农业生产优质高效的主要方向。