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1.

Purpose

Soil quality (SQ), a measure of the sustainability of land use and soil management practices, can be assessed by indicators including soil physical, chemical, and biological properties. Our primary objectives were to investigate the influence of consecutive cultivation and different crop rotation systems on individual SQ indicators and to examine the impact of rotation systems on SQ using soil quality index (SQI) model.

Materials and methods

A site-specific selection of 17 potential SQ indicators representing soil chemical and physical attributes (0–10 cm) and groundwater features on 60 sampling locations and 10 representative soil profiles was chosen in a typical coastal newly reclaimed farmland of north Jiangsu Province, China. Using ANOVA analysis, the crop rotation effect was analyzed by comparing SQ indicators between rice/rape rotation soil and cotton/barley rotation soil. An overall SQI was calculated to examine whether plant biomass indices exactly responded to the SQI value.

Results and discussion

Results indicated that cultivation had significant effect on some soil profile characteristics, including SOM, SOCD, AP, CEC, AK, ECe, and I f. Crop rotation systems also had significant influence on some SQ indicators. Compared with cotton/barley rotation soil, rice/rape rotation soil was characterized by higher organic matter, undifferentiated nutrient storage and salinity/alkalinity, lower water accommodation and infiltration, and adverse groundwater conditions. Cotton/barley rotation had higher SQI values over rice/rape rotation (0.523 vs. 0.422). SQ indicators of SARe, ECe, and WTg contributed the most to the overall SQI value for each rotation system. Plant biomass indices significantly correlated with the SQI values for both rotation systems, suggesting that the SQI values essentially reflected the status of SQ.

Conclusions

Such results allowed us to conclude that cotton/barley rotation system contributed more to the improvement of SQ than rice/rape rotation system in coastal farming area. Also, we suggested SOCD, AK, ρ b, WTg, and ECg as the minimum data set for SQ assessment, as they had potential in discriminating the effect of rotation systems on SQ between the rotation systems used here.  相似文献   

2.
Abstract

Sustainable production in the Everglades Agricultural Area (EAA) is confounded by decreasing soil depth and high annual rainfall. Formerly a sawgrass marsh, Histosols predominate much of the EAA and these soils have frequently flooded following their drainage in the early 20th century. Subsidence has increased inundation frequency as soil depth has decreased to less than 25?cm in many locations. A 2-year lysimeter study was conducted to examine alternative management practices for improved agricultural sustainability given frequent flooding and reduced oxidation rates on Histosols. Specific management factors examined included water-table, soil depth, and nitrogen (N) fertilizer effects on sugarcane leaf nutrient concentrations and soil nutrient cycling. The trial utilized soil depths of 13 and 25?cm, water tables of constant and periodically flooded, and N fertilizer rates of 0 and 168?kg ha?1?year?1. Periodic flooding increased plant uptake of manganese (Mn), silicon (Si), and boron (B). Yield increases associated with additional N indicate a potential need to develop fertilizer rate recommendations for shallow Histosols. Soil depth impacted sugarcane nutrient uptake with 25?cm of soil depth significantly affecting examined leaf nutrient concentrations except iron (Fe). Sugarcane yield may benefit if additional N and potassium (K) are added at rates specific to soil depth. Proximity to bedrock led to excessive calcium (Ca) uptake and low K and Fe DRIS (Diagnosis and Recommendation Integrated System) values were below recommendations. Data from this study can assist development of precision agricultural practices in the EAA that utilize soil depth.  相似文献   

3.
土壤芳基硫酸酯酶及其活性和农业措施影响   总被引：2，自引：0，他引：2  
张玉兰  陈利军 《土壤通报》2006,37(4):792-798
硫是作物生长发育的必需营养元素,但土壤的缺硫现象日益严重,土壤硫营养逐渐成为作物产量和质量的重要限制因子。土壤芳基硫酸酯酶能酶促土壤有机硫的矿化,在硫素的生物化学循环和植物的硫营养中具有重要的作用,是反映土壤质量的一个重要生物学指标。本文在阐述土壤芳基硫酸酯酶的重要作用、来源、存在方式等的基础上,综述了国内外该酶对农业技术措施的响应的研究,为不同农业管理制度下土壤芳基硫酸酯酶活性的调节提供参考。  相似文献   

4.
Local communities often have substantial knowledge related to trends in soil quality and the associated limiting factors. Despite this, soil quality (SQ) degradation is a critical problem in Ethiopia and there is little or insufficient scientific information documenting local community experience in assessing SQ. This paper presents experiences of local communities in diagnosis of SQ and assesses the contribution of local knowledge as a strategy for sustainable development decision making within the Mai-Negus catchment of northern Ethiopia. Participatory transect-walks, group discussions and field observation which complemented by household interview were used to acquire data. Farmers identified SQ indicators e.g., crop yield, soil depth, erosion and sedimentation as their basis of categorizing the soils into high, medium and low SQ. They were also able to identify severely degraded areas (hotspots) and underlying causes. Significant variations (P ≤ 0.05) were shown between the proportions of farmers used certain SQ indicator and those who didn't while categorizing SQ. Local farmers involved in this study demonstrated their capability to suggest appropriate land management solutions for specific problems. This study demonstrates the benefit of involving local farmers in both problem identification and solution development so that anti-degradation technologies can easily be implemented and adopted.  相似文献   

5.
为探究黄淮海旱作区耕层土壤质量特征,基于土壤物理、化学及剖面特征,建立黄淮海旱作区耕层土壤质量评价指标体系,运用主成分分析法构建耕层质量评价指标的最小数据集（minimum data set,MDS）,结合障碍因子诊断模型揭示黄淮海旱作区耕层土壤质量特征及其障碍因素。结果表明：1）研究区耕层土壤质量评价最小数据集由土壤有机质、土壤阳离子交换量、土壤pH、耕作层厚度、耕作层穿透阻力和耕作层压实度构成,基于最小数据集和全指标数据集的耕层土壤质量指数间显著正相关（R2=0.61,P＜0.05）,Nash有效系数和相对偏差系数分别为0.601和0.181,表明最小数据集的指标能够代替全部数据集指标对黄淮海旱作区耕层质量进行评价;2）研究区耕层土壤质量总体处于中等水平,质量指数为0.25～0.61;适宜耕层各项指标如下：耕作层厚度不小于17.20 cm,耕作层穿透阻力不大于896.10 kPa,耕作层土壤压实度不大于78.01%,pH值为8.01～9.37,有机质不小于17.87 g/kg,阳离子交换量不小于21.13 cmol/kg;3）黄淮海旱作区存在明显的障碍类型,耕层障碍可分为薄化紧实与养分贫瘠障碍耕层、养分贫瘠耕层、土壤紧实型耕层3类。其中有机质含量低、阳离子交换量低、耕作层压实度过高是黄淮海旱作区耕层质量主要障碍。研究为黄淮海旱作区耕层土壤质量提升和改善提供理论支撑。  相似文献   

6.
Straw incorporation is generally considered an effective agricultural management practice that improves nutrient cycling and maintains soil fertility. To study the interactive effects of straw returning factors on soil organic carbon and available nutrients, a17-month(May 6, 2016 to October 6, 2017) experiment was conducted on straw incorporation by using response surface methodology under a three-factor(straw length, amount, and burying depth), five-level quadratic orthogonal rotation experimental design. Weight was assigned to each indicator for soil carbon and nutrients and then a comprehensive indicator was established. Then, a second-order polynomial model of the three straw returning factors was established using response surface methodology. Results indicated that17 months after straw incorporation, straw amount and burying depth had significant effects on the comprehensive indicator of soil carbon and nutrients. Straw length and the interactions of straw amount and burying depth showed no significant effects on the comprehensive indicator of soil carbon and nutrients. It was concluded that 17 months after straw incorporation, the highest value of the comprehensive indicator of soil carbon and nutrients was achieved when the straw length, amount, and burying depth were approximately 17–20 cm, 740–840 g m~(-2), and 9–13 cm, respectively, which can be recommended as the most suitable parameters for use in straw returning in the study area.  相似文献   

7.
Sustainability of agricultural management systems has become an issue of wide public concern and international debate. One result is that soil quality assessment has been suggested as a tool for evaluating sustainability of soil and crop management practices. Our objective was to adapt a soil quality index to assess the effects of three long-term tillage systems on sloping Grantsburg silt loam soil. Soil quality was evaluated using a framework that included three soil functions: (1) resist erosion (water relations), (2) provide plant nutrients (nutrient relations), and (3) provide a favorable root environment (rooting relations). A score for each of these functions was computed using measurements (indicators) that were normalized with one of the three (more is better, optimum, or worse) scoring functions. Six different indices were developed from a basic framework. Modifications included changing the weighting factors, threshold limits, or type of scoring function applied to indicators, and the addition of air-filled and water storage porosity to the nutrient and rooting relations functions. Changing threshold limits and the type of scoring function used for surface residue improved the correlation between water relations and soil loss. The addition of porosity indicators increased the sensitivity of nutrient and rooting relations functions to yield and cone index, respectively, and resulted in a better correlation between porosity indicators and plant population. Computing soil quality indices helped to combine different soil properties and processes into a simple tool that explained changes in complex soil properties in response to different tillage practices. This supports previous studies suggesting that computing soil quality indices and functions could be useful for selecting management practices to maintain or improve soil quality. Our results demonstrated that adjusting threshold limits for local conditions can make the function ratings more or less sensitive to the management practices being evaluated.  相似文献   

8.
赵贺  王绪奎  刘绍贵  高飞  李鹏  李其胜  李辉信  焦加国 《土壤》2020,52(6):1230-1238
为明确江苏稻麦轮作区土壤质量状况，本研究基于2008～2015年期间江苏省稻麦轮作区10681个测土配方施肥样点的数据，通过相关性和主成分分析筛选了江苏省稻麦轮作区的最小数据集(Minimum data set, MDS)，并对土壤质量进行评价。结果表明：基于水稻产量分析，江苏省稻麦轮作区的最小数据集包括有机质、有效磷、速效钾、有效铁和有效硼。基于最小数据集得出的江苏省土壤质量指数(SQI-MDS)变化范围在0.136～1.000之间（均值0.674），与基于全量数据集得出的土壤质量指数（SQI-TDS）之间呈极显著正相关关系（R2=0.720），这说明最小数据集能够较好的代替全量数据集指标。本研究结果可为江苏省不同地区的稻麦耕地质量恢复和提升及稻麦粮食生产提供科学指导。  相似文献   

9.
The use of variable rate technology has become increasingly popular for applying plant nutrient elements. The most widely used method for determining variable fertilizer rates is presently based on soil testing and yield mapping. Three field studies (Bumeyville 1995, Burneyville 1996, and Ardmore 1996) were initiated in established Midland bermudagrass [Cynodon dacrylon (L) Pers.] pastures to determine the relationship between spectral radiance at specific wavelengths with forage nitrogen (N) removal and biomass, and to determine field variability of soil test parameters. Variable N (applied to 1.5 × 2.4 m subplots within 2.4 × 45.7 m main plots), fixed N and check treatments were evaluated at each location. Spectral radiance readings were taken in the red (671±6 nm), green (570±6 nm), and near infrared (NIR) (780±6 nm) wavelengths. The normalized difference vegetation index (NDVI) was calculated as NIR‐red/NIR+red. Variable N rates were applied based on NDVI. The highest fixed variable N rate was set at 224, 336, and 672 kg N ha‐1 for Burneyville, 1995, 1996, and Ardmore, 1996, respectively. At Bumeyville, soil samples were collected in all variable rate plots (1.5 × 2.4 m) and analyzed for various soil test characteristics. NDVI, red, green, and NIR spectral radiance readings were correlated with bermudagrass forage N removal and yield. Correlation of forage yield and N removal with red, NIR, and NDVI were best with maximum forage production, however, when forage production levels were low correlation decreased dramatically for the red wavelength compared with NIR and NDVI. Forage yield and forage N removal in variable rate treatments increased when compared to the check while being equal to the half‐fixed and fixed rates where higher N rates were applied. Also, variability about the mean in variable rate plots was significantly lower than half‐fixed and fixed rates which supports adjusting N rates based on indirect NDVI measurements. Variable N rate plots reduced fertilizer inputs by 60% and produced the same yield as fixed rate plots, while fixed and half‐fixed rates did not increase N content in the forage over that of the variable rate treatment. Soil sample data collected from small consecutive plots (<4 m2) was extremely variable indicating that intense sampling would be needed if variable fertilizer application were to be based on soil test results.  相似文献   

10.
沂蒙山区是北方土石山区水土流失治理重点区域,定量评价不同治理模式下的土壤质量,进而优选适宜的生态恢复措施,是推进沂蒙山区生态环境建设的关键。以沂蒙山区4种治理模式(乔草混交、土坎梯田+果树种植、撂荒、封禁植草)为研究对象,基于主成分分析、相关性分析和Norm值计算,对土壤养分、孔隙、水分、容重4类9项土壤属性指标进行筛选,构建土壤质量评价最小数据集。结果表明：(1)治理模式对土壤理化性质具有明显影响,硝态氮属于极敏感指标,全氮为高度敏感指标,而有机质、全磷、无机磷、田间持水量与饱和含水量属中度敏感指标,土壤容重为低度敏感指标;(2)影响沂蒙山区土壤质量的最小数据集指标包括全氮、土壤孔隙度、容重,经总数据集验证所构建的最小数据集可体现沂蒙山区土壤质量有效信息、准确性较高;(3)沂蒙山区不同治理模式下土壤质量指数介于0.41～0.53,土壤质量属于中等水平,且0—5 cm和5—10 cm土层的土壤质量指数较10—20 cm分别增加136.20%和37.60%。土壤质量表现为乔草混交>土坎梯田+果树种植>撂荒>封禁植草。综上,在水土流失严重、土壤较为贫瘠的沂蒙山区,生态恢复...  相似文献   

11.
为了探索黄淮海小麦生产适宜的耕作模式,该研究设计长期定位试验（2017年—2022年）对比了简化耕作模式深耕（deep tillage, DT）、轮耕（rotational tillage, RT）和免耕（no-tillage, NT）对冬小麦产量和土壤水肥状况的影响。结果表明：RT处理显著提高了冬小麦苗期0～20 cm土层土壤水分吸收利用情况,冬小麦孕穗期、灌浆期RT处理0～20、>20~40 cm土层土壤含水量显著高于DT、NT处理。RT处理0～20、>20～40 cm土壤全氮、有机质含量和碳氮比含量较DT、NT处理显著提高, 2021—2022年0～20 cm土壤全氮、有机质含量、碳氮比RT处理较DT和NT处理分别显著提高40.45%和31.58%、56.66%和45.34%、11.62%和9.91%。2020—2021年和2021—2022年RT处理冬小麦产量较DT、NT处理分别显著提高20.20%、13.39%和20.35%、18.74%。RT处理显著增加了冬小麦千粒质量,其产量变异系数最低,产量可持续指数最高,说明RT处理有助于增加冬小麦生产力稳定性和可持续性,可以实现黄淮海冬小麦高产稳产。研究可为黄淮海平原冬小麦生产应用一年深耕、两年免耕的轮耕耕作模式提供理论指导与技术支撑。  相似文献   

12.
为探究滇中高原华山松植物多样性与土壤生物肥力的关系,运用野外调查法和实验室分析法对玉溪市磨盘山国家森林公园的华山松天然次生林进行了研究。结果表明:1磨盘山华山松天然次生林形成以华山松为优势种的针阔混交林,其物种组成单一、植物多样性较低,共出现维管束植物13科15属15种。2华山松林下有机质、全氮、碱解氮、全磷、有效磷、速效钾含量,酶活性及微生物数量随土层深度的加深呈递减趋势,pH、全钾含量随土层深度的加深而呈递增趋势。3主成分分析结果显示,土壤养分、过氧化氢酶、转化酶和微生物都能较好地反映土壤生物肥力特征,多样性指数、优势度指数以及丰富度指数这3个因子能够较好地反映植物多样性。4华山松植物多样性与土壤肥力特征具有明显的相关性,其中对植物多样性影响较大的土壤肥力指标有真菌、过氧化氢酶、全氮、速效钾、全钾、转化酶、细菌、全磷、有效磷。  相似文献   

13.
Abstract

Root length and root distribution in the soil profile is important in determining the amount of nutrients and water taken up by the plant. Data about year to year variation of corn (Zea mays L.) root growth and its relation to nutrient uptake are limited. An evaluation of the importance of root system size and distribution on P and K uptake and corn yield was made from samples taken annually from a long‐term fertility experiment on Raub silt loam, fine silty, mixed, mesic Aquic Argiudolls. Root density varied with soil depth among years, whereas P and K fertilizer treatment had no measureable influence on total root length. Ear leaf P concentration was highly correlated with the amount of roots in the 0 to 15 cm layer which contained most of the available P. Since P was not appreciably limiting corn yield, no significant relation was found between yield and P content of the ear leaf. Yields on K deficient plots were positively correlated with root density in the topsoil. Correlations of root densities in the deeper soil layers with both yield and ear leaf nutrient concentration became increasingly smaller with depth in the soil profile. The results indicate that root length plus root distribution in the soil may influence year to year variation in yield particularily on soils having low available nutrient levels. This variation in root growth may be responsible for differences among years in the response of crops to applied P and/or K.  相似文献   

14.
The aim of this study is to examine the horizantal and vertical spatial changes of soil quality (SQ) in rice-cultivated soils located on the Bafra Deltaic Plain—one of the most important alluvial deltaic plains and production centers of Turkey. The study examines these spacial changes by calculating the soil quality index (SQI) for soils 0–30 cm and 30–60 cm deep. For SQI calculations, seventeen potential physicochemical SQ indicators of eighty-three soil samples were assessed. Quality indicators to be used in these calculations were selected by considering the clay content, correlation relationship, and principal components analysis (PCA) of potential quality indicators. Clay, silt, sand, electrical conductivity (EC), exchangeable calcium (Caexc), and exchangeable magnesium (Mgexc) were selected as quality indicators, and silt was found to be the most important quality indicator for both soil depths. The SQ of researched soils changed from low to high for both soil depths.  相似文献   

15.
基础地力产量是表征土壤生产能力的重要指标,对基础地力产量及土壤养分影响因子的研究可为河北省中南部冬小麦产区地力提升及增产提供指导和理论依据。该文利用河北省2006—2013年测土配方施肥项目布置的876个示范试验数据,研究了河北中南部冬小麦基础地力产量、产量差及基础地力贡献率,利用边界线分析方法,将农田土壤养分因子对基础地力产量差的贡献率进行了定量化,解析了土壤养分影响因子。结果表明:河北冬小麦基础地力产量在1 080～7 404 kg/hm~2之间;以最高产量为参照,各试验点的基础地力产量差为69～6 324 kg/hm~2(平均值为2 831 kg/hm~2)。基础地力对农户产量的贡献率均值为71.1%,基础地力贡献率随基础地力产量的增加而提高,呈显著正相关关系,基础地力小麦产量每提高1 000 kg/hm~2,基础地力贡献率提高8%。应用边界线分析方法对土壤养分因子与基础地力产量进行分析,土壤pH、有机质、碱解氮、有效磷和速效钾5种土壤养分因子与边界点均有较好的拟合关系(R2分别为0.837、0.881、0.750、0.682和0.951),土壤基础养分对基础地力产量差的贡献率以有机质、pH值和碱解氮最高,分别为16.6%、10.9%和10.5%,速效钾和有效磷的贡献率分别为4.1%和2.9%,河北省农田土壤培肥时应优先提升有机质与碱解氮,并优先调节土壤pH。河北省冬小麦田土壤在pH值8.1、有机质24.6 g/kg、碱解氮120.6 mg/kg、有效磷12.4 mg/kg、速效钾89 mg/kg时养分效率最高,是农田土壤最优养分目标。边界线方法能够对区域尺度基础地力产量土壤养分影响因子进行分析,可为农田土壤培肥指明方向。  相似文献   

16.
中国东北农田土壤质量评价的最小数据集选择   总被引：2，自引：0，他引：2  
Soil quality assessment provides a tool for agriculture managers and policy makers to gain a better understanding of how various agricultural systems afect soil resources.Soil quality of Hailun County,a typical soybean (Glycine max L.Merill) growing area located in Northeast China,was evaluated using soil quality index(SQI)methods.Each SQI was computed using a minimum data set(MDS) selected using principal components analysis(PCA)as a data reduction technique.Eight MDS indicators were selected from 20 physical and chemical soil measurements.The MDS accounted for 74.9% of the total variance in the total data set(TDS).The SQI values for 88 soil samples were evaluated with linear scoring techniques and various weight methods.The results showed that SQI values correlated well with soybean yield (r=0.658**) when indicators in MDS were weighted by the regression coefcient computed for each yield and index.Stepwise regression between yield and principal components (PCs) indicated that available boron(AvB),available phosphorus (AvP),available potassium (AvK),available iron (AvFe) and texture were the main factors limiting soybean yield.The method used to select an MDS could not only appropriately assess soil quality but also be used as a powerful tool for soil nutrient diagnosis at the regional level.  相似文献   

17.
不同施氮水平下水稻的养分吸收、转运及土壤氮素平衡   总被引：19，自引：7，他引：12  
【目的】为解决东北地区水稻合理施用氮肥问题,系统研究了不同施氮水平条件下,东北水稻产量及构成因素、养分吸收、转运、氮肥利用效率及土壤氮素平衡的变化,并探讨各养分间及其与产量间的关系,为东北地区水稻合理施氮提供理论基础。【方法】于2012~2013年在吉林省松原市前郭县红光农场,选用当地主栽水稻品种富优135和吉粳511为材料,设置施N 0、60、120、180和240 kg/hm25个水平。于水稻返青期、分蘖期、抽穗期、灌浆期及成熟期采集植株样本,分为茎鞘、叶片和籽粒三部分,测定氮、磷、钾含量,计算水稻主要生育期植株养分吸收、转运、氮素利用特性的相关参数及各养分吸收、转运与产量间的关系。水稻移栽前和收获后采集0—100 cm土壤样品,每20 cm为一层(共5层),测定铵态氮、硝态氮含量,并根据各层土壤容重计算0—100 cm土体无机氮积累量,分析土壤氮素平衡状况。【结果】施氮量60~180 kg/hm2范围内,水稻产量随着施氮水平的提高而增加,氮肥用量超过180 kg/hm2水稻产量下降。结合当年水稻和肥料价格,根据水稻产量(y)和施氮量(x)拟合方程,得出最高产量氮肥用量分别为212.8 kg/hm2和220.6 kg/hm2,施氮范围在202.2~231.6 kg/hm2之间,最佳经济产量氮肥用量分别为203.0和209.1 kg/hm2,施氮范围在192.9~219.6 kg/hm2之间。施用氮肥可显著提高水稻主要生育期氮、磷、钾吸收量,且能提高水稻抽穗期氮、磷、钾养分向籽粒的转运,施氮量180 kg/hm2处理抽穗期各养分累积量与籽粒转运量呈正比,当氮肥用量超过180 kg/hm2后,氮、磷、钾养分向籽粒转运出现负效应。氮素农学利用率和偏生产力随着施氮水平的提高而显著下降,氮肥当季回收率以施氮量180 kg/hm2处理最高。相关分析表明,水稻主要生育期氮、磷、钾的吸收、转运与产量间均存在显著或极显著的正相关性,其中灌浆期氮、磷、钾的吸收状况与产量间的相关系数最大。施用氮肥可显著提高收获后0—100 cm土壤中残留无机氮(Nmin),氮素表观损失量随施氮水平的提高而增加。【结论】适宜的氮肥用量可显著提高水稻产量,各生育时期养分吸收总量,提高水稻生育后期秸秆中氮、磷、钾向籽粒的转运量,并能降低土壤氮素表观损失量。综合考虑提高水稻产量、效益、氮肥当季回收率及维持土壤氮素平衡等因素,在本试验条件下,施氮范围在192.9~219.6 kg/hm2。  相似文献   

18.
Sustainable land management decisions at all scales require solid, science-based information. Soil quality assessment can provide this regarding soil physical, chemical, and biological characteristics and the ability to provide ecosystem and societal services. Our objective was to make a regional assessment of soils in the Garhwal Himalayas to determine their ability to perform various functions and respond to external influences. Five functional categories were assessed using 13 soil parameters focused on ecological sustainability. Human land use effects on soils were referenced to natural woodlands at each landscape position. Within upper-slope regions, flora and fauna habitat, moisture retention, organic matter and nutrient cycling, air and water infiltration and resistance to erosion were decreased 35, 27, 24, 24, and 9%, respectively. At mid-slope positions the order and magnitude of decrease were organic matter and nutrient cycling, flora and fauna habitat, and moisture retention (26, 22, and 16%, respectively). Changes within the valley were lowest, averaging − 3% for flora and fauna habitat and − 13% for organic matter and nutrient cycling. We conclude that the minimum data set (MDS) used provided a representative assessment of soil quality and could serve as a basis for assessment in similar tropical watersheds.  相似文献   

19.
Abstract

Plant analysis is an important component of soil fertility and plant nutrition research. Plant analysis at harvest of the crop forms the basis for constructing nutrient balances and assessing the nutrient needs of production systems. Amounts of macro‐ and micronutrient elements removed by improved, upland and lowland rice cultivars were determined in field experiments at two sites in Ivory Coast. Amounts of nitrogen (N), zinc (Zn), and manganese (Mn) removed for 11 rice grain yield by upland and lowland rice cultivars were similar, but the amounts of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) removed were higher for lowland than upland rice. The nutrient element harvest indexes (amount in grain/amount in grain plus straw) varied between the cultivars, but more importantly, among nutrient elements. On average the nutrient harvest index was highest for P (69%) and lowest for K (10%). The results suggest that the nutrient requirement of rice for K can be met to a large extent through the recycling of K in rice straw. The amounts of other major nutrients, N and P in the straw were small and hence less scope for supplying these nutrients through the recycling of rice straw.  相似文献   

20.
不同覆盖方式对新复垦区土壤水热及春玉米产量的影响   总被引：2，自引：0，他引：2  
随着城市化进程的加速发展,我国净耕地面积持续减少,合理开发利用潜在土地资源,对于保障我国粮食安全具有重要意义。为了探讨不同覆盖耕作方式对新复垦区土壤水热及作物生长的影响,通过2018年和2019年连续两年田间试验,研究了传统耕作(CK)、地膜覆盖(FM)、秸秆深埋(BS)和秸秆深埋+地膜覆盖(F+S) 4种处理对土壤水分、温度和春玉米生长及产量的影响。结果表明:2018年,F+S、BS、FM处理玉米生育期内0～20cm及20～40 cm土层平均土壤含水率分别较CK增加24.4%、16.5%、12.6%及9.1%、3.2%、3.7%。2018年玉米苗期, 0～100 cm土壤蓄水量表现为FMF+SCKBS,明显表现为有覆膜处理(F+S和FM)的土壤蓄水量高于不覆膜处理(BS和CK)。2019年玉米苗期,土壤蓄水量则表现为F+SBSFMCK。与CK相比,春玉米全生育期不同覆盖耕作处理条件下各土层(5～25 cm)土壤温度均有所提高,具体表现为F+SFMBSCK,各处理土壤温度随土层深度表现为降低趋势。以表层5 cm土壤温度增幅最大,覆盖耕作处理的增温效应在全生育期表现为前期明显而后期弱化。各处理株高变化趋势一致,在播种后70d左右达到峰值,随后出现小幅度下降并最终保持稳定。试验期,株高和叶面积均表现为地表有覆膜的处理高于未覆膜处理(P0.05)。2018年, F+S、BS和FM处理玉米产量均显著高于CK(P0.05),2018年和2019年,各处理产量分别较CK增加17.0%、13.5%、6.6%和30.5%、23.9%、3.8%。产量构成逐步回归分析结果表明,穗长对产量的影响最大,产量与穗行数和百粒重呈正相关关系。秸秆深埋+地膜覆盖处理(F+S)可以综合发挥二者优势,有效调节土壤水热状况,改善土壤环境,促进作物生长发育,从而获得较高的产量,可作为新复垦区春玉米适宜的种植管理方式。  相似文献   

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