基于WebGIS 中国农田养分平衡与环境风险评价系统的构建

在分析了ArcIMS的体系结构及其运行机制的基础上,基于ArcIMS9.0平台,采用空间数据引擎技术、数据库技术及ASP.NET编程技术,结合农田养分平衡模型和环境风险评价模型,设计开发基于WebGIS中国农田养分平衡与环境风险评价系统。系统主要包括远程基础数据库管理、基本数据查询分析、养分专题制图、在线养分平衡分析、环境风险评价分析及施肥策略咨询等6大功能,将农业基础数据通过模型运算的结果与地图数据相结合,实现了全国范围内基本农业数据、农田养分平衡与环境风险等信息的在线共享、评价与施肥咨询服务。     

Nutrient management for intensive animal agriculture: policies and practices for sustainability

Abstract. The intensity of animal production around the world has increased substantially during the last half-century, which has led to large problems with the disposal of manures and waste waters. The focus of this paper is on the development of national policies to improve the nutrient management of concentrated animal feeding operations (CAFOs), where nutrients are invariably in surplus. To create proper nutrient management strategies for CAFOs, and to avoid environmental problems when surplus nutrients enter air, soil and water, we need to know the number of animals/birds in the unit, the quantity of manure/slurry produced, how this material is stored and handled and how much land is available for manure spreading. In this paper, we discuss the development of nutrient management strategies for CAFOs in Europe and North America, and the voluntary measures and environmental regulations related to this. For the planning of nutrient management to be comprehensive and efficient, we need expertise from several disciplines. This planning includes development of: animal diets that reduce the amounts of excreted nutrients; efficient storage and land application technologies; land application programmes to optimize yields and reduce nutrient losses; and strategies for use of excess manure outside the farm. Also, large-scale efforts involving many stakeholders (farmers, governments and private industry) are needed to solve problems with nutrient imbalances over the long term. Efforts along these lines include manure relocation, alternative uses of manures, nutrient trading, and a general extensification of animal agriculture. The overall guiding principle for policies and planning should be a balance of nutrients, on farms as well as at larger scales.     

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。     

1980-2015年中国农田生态系统的N素平衡

Surface nitrogen （N） balances for China＇s crop production systems was estimated using statistical data collected from 1980 to 2004 at the national and provincial scale and from 1994 to 1999 at the county level. There was a surplus N balance throughout these periods, but the surplus was nearly stable in recent years. Projections using nonseasonal Box-Jenkins model or exponential models show that the N surplus for the total cultivated land in China was likely to increase from 142.8 kg ha^-1 in 2004 to 168.6 kg ha 1 in 2015. The N balance surplus in the more developed southeastern provinces was the largest, and was slightly less in the central region, which caused the nitrate pollution in the ground water. The N surplus was much less in the western and northern provinces because of lower synthetic fertilizer inputs. The region with high N risk includes Beijing Municipality and Jiangsu, Zhejiang, Fujian, Guangdong, Hubei, and Shandong provinces for 2002-2004. The projections suggested that 15 provinces （or municipalities） in the middle and southeastern part of China except Jiangxi and Shanxi provinces would become the high-risk region by 2015. The level of economic development, transportation, and labor force condition had an important effect on the N balance surplus at the county level, but the last two factors showed remarkable impact at the provincial level. To decrease the nonpoint pollution （Npp） risk from crop production, the authors suggested to reduce the target level for national grain self-sufficiency to 90%-95% and change the regional structure of grain production by moving some of the future grain production from the high Npp risk areas of eastern China to parts of the central and western provinces where the Npp risk was much less.     

不同轮作模式农田钾养分表观平衡及其对土壤速效钾含量的影响

通过连续3年监测上海郊区43块定位农田,比较了50种作物以及5种不同轮作模式农田的钾养分表观盈余状况及其对土壤速效钾含量的影响。结果表明：(1)不同作物农田的钾养分盈余趋势为水生蔬菜类、果树类>旱作蔬菜≥草皮>大田作物;不同轮作模式农田钾养分盈余大小表现为作物轮作>菜作轮作>草皮单作>菜菜轮作>果树单作;(2)不同作物及轮作模式农田收获时土壤速效钾含量随土层的加深而逐渐增加,钾养分盈余多的农田土壤的表层速效钾含量也高;(3)不同作物及不同轮作模式农田钾养分盈余量与收获时土壤表层(0~30 cm)的速效钾含量呈正相关,但未达显著水平。     

不同轮作模式农田磷养分表观平衡及其对土壤Olsen-P含量的影响

通过连续3年监测上海郊区43块定位农田研究,比较了50种作物以及5种不同轮作模式农田的磷养分表观盈余状况及其对土壤Olsen-P含量的影响。结果表明:(1)不同作物农田的磷养分盈余趋势为水生蔬菜类果树类旱作蔬菜≥草皮大田作物;不同轮作模式农田磷养分盈余趋势为菜菜轮作果树单作菜作轮作草皮单作作物轮作;(2)不同作物及轮作农田收获后土壤Olsen-P含量随土壤深度的增加而逐渐降低,磷养分盈余量多的农田土壤Olsen-P含量也高;(3)不同作物以及轮作农田磷养分盈余与收获时土壤表层(0~30cm)的Olsen-P含量呈显著正相关。     

海南农田养分平衡状况及环境风险评价

  【目的】  海南是我国区域经济作物种植面积占比最高的省。以海南主要农作物为对象,研究海南农田养分投入强度和作物养分平衡状况,从活性氮损失、温室气体排放和水体富营养化等方面评价施肥引起的环境风险。  【方法】  根据《海南统计年鉴》中的农作物种植结构,将海南省农作物分为粮食、蔬菜、水果和其他经济作物4类。采用随机抽样方法进行大样本农户问卷调研,共获取1199个有效样本。通过统计分析定量了海南岛主要农作物和各市县养分投入强度,化肥、有机肥施用结构,计算海南岛典型农作物体系水稻–辣椒轮作、香蕉和菠萝的氮磷养分平衡;采用相应环境模型,定量评价由于施肥带来的活性氮损失、温室气体排放以及富营养化效应等环境影响。  【结果】  目前海南主要作物化肥N、P₂O₅、K₂O养分的平均投入分别为261、206、225 kg/hm2,分别高出全国平均水平10%、101%、148%,其中蔬菜磷和钾养分投入量分别高出全国平均水平164%和138%。全海南省各市县相比,沿海市县化肥养分施用强度高于中部市县,以昌江、海口的氮磷钾养分投入量大,高于投入最低的白沙、琼中等市县1.0～2.2倍。单质化肥以尿素、过磷酸钙和氯化钾为主,复合肥主要为N–P₂O₅–K₂O 15–15–15型。有机肥占总养分投入比例较低,粮食、蔬菜和水果的有机氮投入量分别为粮食、蔬菜和水果类作物总氮投入量的4%、20%和12%,低于全国平均水平。水稻–辣椒轮作、香蕉、菠萝种植体系的氮素单季盈余分别为N 520、675和668 kg/hm2,磷素单季盈余分别为P 217、277 和228 kg/hm2,香蕉和菠萝种植体系氮素盈余是环境安全阈值的8倍以上。3个作物体系中,菠萝生产的单位面积活性氮损失、单位面积温室气体排放和富营养化效应最高,分别达到N 201 kg/hm2、CO₂-eq 13112 kg/hm2和PO₄-eq 121 kg/hm2。活性氮损失的4个途径中,贡献最大的是施用环节,硝酸盐淋洗高达85%,其次是氨挥发、氧化亚氮排放和肥料生产运输阶段产生的活性氮损失。肥料生产运输过程产生的温室气体排放与施用阶段相当。肥料施用阶段排放带来的单位面积富营养化潜值大于生产阶段,氮肥和磷肥施用对富营养化效应的贡献度分别为62.5%和35.7%。  【结论】  海南省农业生产中经济作物占比高,养分投入强度大,磷、钾施用过量问题尤为突出,有机肥施用占比低,养分总体盈余高。由于经济作物多分布于沿海市县,沿海地区的养分盈余大于中部。养分施用阶段带来的环境风险远大于生产阶段。硝酸盐淋洗是活性氮损失的主要形式,氮肥和磷肥是水体富营养化的主要贡献者。菠萝生产体系的环境风险最高,其养分管理模式亟需优化。     

中国农业生态系统氮磷钾平衡时空变异研究

Nitrogen, phosphorus, and potassium balances for agroecosystems in China from 1993 to 2001 were calculated at national and provincial levels using statistical data and related parameters, and their spatial and temporal variabilities were analyzed with GIS to estimate the potential impacts of nutrient N, P and K surpluses or deficits to soil, water and air. At the national scale, the N and P balances from 1993 to 2001 showed a surplus, with the nitrogen surplus remaining relatively stable from 1997-2001. Although during this period the P surplus pattern was similar to N, it had smaller values and kept increasing as the use of phosphate fertilizer increased year by year. However, K was deficient from 1993 to 2001 even though from 1999 to 2001 the K deficit decreased. The spatial analysis revealed higher N surpluses in the more developed southeastern provinces and lowest in the western and northern provinces where there was less chemical fertilizer input. The serious K deficit mainly occurred in Shanghai and Beijing municipalities, Jiangsu, Zhejiang and Hubei provinces, and Xinjiang autonomous regions. For the years 1992, 1996 and 2001, N surpluses and K deficits had significant positive spatial correlations with per capita gross domestic product (GDP), per capita gross industrial output value, and per capita net income of rural households. This showed that the level of economic development played an important role on nutrient balances in the agroecosystems.     

黑龙江垦区农田土壤养分平衡分析与评价

养分资源高效利用是农业绿色发展的重要环节。黑龙江垦区是中国粮食主产区之一,对其进行农田土壤养分平衡评价至关重要。该研究以黑龙江垦区为研究对象,采用农田土壤养分平衡方法,分析与评价其2000-2018年农田土壤氮、磷、钾养分输入与输出情况。结果表明:1)2000-2018年黑龙江垦区农田土壤氮、磷、钾输入与输出整体呈现"平稳-增长-下降后平稳"的趋势,养分输入以化肥为主,养分输出以籽粒和秸秆为主。2)黑龙江垦区农田土壤单位面积养分输入量较为稳定,并且所带来的经济效益在增加。3)2017年以来黑龙江垦区农田土壤氮和钾处于养分平衡状态,而磷处于养分盈余状态。2018年黑龙江垦区氮、磷、钾利用效率分别为51.03%、27.98%、10.04%。建议黑龙江垦区大力推广有机无机肥配施,开展农田土壤养分平衡长期调查与监测,促进区域农业绿色发展。     

环渤海低平原农田生态系统养分循环与平衡研究

了解农田养分输入、输出和平衡状况,以及土壤肥力现状与变化特征,对实现养分资源优化管理、地力的持续提升、肥料利用率提高和农业可持续发展具有重要意义。基于1985年、2000年和2014年河北省南皮县国民经济统计资料,分析了从1985年到2014年县域农田生态系统养分循环与平衡状况;利用1981年第2次土壤普查和2015年实测南皮县域土壤耕层养分含量数据,探讨了耕层土壤养分变化及空间分布格局特征。结果表明,1985—2014年南皮县农田养分输入输出均呈持续上升趋势, NPK养分输入由10701 t增加至23386 t,年递增率2.33%; NPK养分来源结构略有不同, NP来源以化肥为主,其次是人畜粪尿和作物秸秆有机肥源;而K素来源主要是有机肥源。农田养分输出以作物吸收为主,占养分总输出的80%以上, NPK总输出由1985年的9093 t增加到2014年的18846 t,年均增速2.17%。从养分表观平衡的角度看,从1985年到2014年NP始终有大量盈余, P素盈余大于N素, N和P表观平衡率分别为16.8%~34.2%和26.9%~65.5%;若考虑有机氮的有效性问题,1985—2000—2014年3个时段有效氮盈亏率依次为18.1%、6.5%和-7.8%,有效氮平衡由盈余转向亏缺;而K素经历了由赤字逐渐向盈余的转变过程,由1985年的-33.5%赤字发展至2014年的33.6%盈余。受农田养分平衡状况的影响,南皮县土壤有机质、全氮、有效磷发生了显著变化,1981—2015年有机质由8.62 g·kg-1增至14.0 g·kg-1,增幅62.4%;全氮由0.542 g·kg-1增至0.908 g·kg-1,增幅67.5%;有效磷由2.0 mg·kg-1增加到20.8 mg·kg-1,增加了9.4倍。而碱解氮和有效钾变化不明显,分别由70.5 mg·kg-1和141 mg·kg-1增加到71.8 mg·kg-1和147 mg·kg-1,相对增幅仅为1.8%和4.2%。建议今后南皮县在农业生产中大力推广科学施肥技术,重视有机肥和化肥配施,推广秸秆还田,通过改进施肥方法提高肥料利用效率;养分管理中应提倡“稳氮、控磷、补钾”的施肥对策,避免过多的盈余养分进入环境。     

基于养分专家系统推荐施肥在东北玉米上的长期综合效应

为明确养分专家系统推荐施肥对东北玉米产量与收益、肥料利用率与土壤养分的长期综合效应,于2012-2020年开展了田间定位试验,共设置5处理：分别为1）不施肥（CK）;2）农民习惯施肥（FP）;3）养分专家系统推荐施肥（NE）;4）在NE基础上配施缓/控释氮肥（NER）;5）土壤测试推荐施肥（ST）。探究9 a 产量与收益、肥料利用率、土壤养分和养分平衡的变化规律。结果表明,NE和ST处理较FP处理显著降低了氮磷肥用量（P<0.05）,显著增加了钾肥用量（P<0.05）。与FP处理相比,NE、NER和ST处理提高了玉米产量、收益及其稳定性。其中均以NE处理最高,之后依次为ST和NER处理。NE、NER和ST处理肥料平均回收利用率、农学利用率和偏生产力较FP处理分别提高了29.0%～40.1%（P<0.05）、31.3%～44.3%（P<0.05）和22.0%～31.7%（P<0.05）,且均以NE处理最高。与FP处理相比,NE、NER和ST处理提高了0～30 cm土壤无机氮含量,降低了30～90 cm土壤无机氮和0～30 cm土壤有效磷含量,而不同施肥处理土壤速效钾含量差异未达显著水平（P>0.05）,其中NE处理与试验起始养分含量最为接近。9 a养分平衡结果显示,FP、NE、NER和ST处理氮、磷均表现为盈余,而钾素表现为亏缺,且NE处理氮、磷盈余量和钾亏缺量均为最低。综上,与农民习惯施肥和土壤测试推荐施肥相比,养分专家系统推荐施肥不仅可提高玉米产量、收益和肥料利用效率,并可保持土壤养分稳定。因此,它是一种适用于中国东北玉米的推荐施肥方法。     

Nutrient Balances of New Zealand Kiwifruit (Actinidia deliciosa cv. Hayward) at High Yield Level

The productivity of kiwifruit (Actinidia deliciosa) orchards varies widely in New Zealand. We hypothesized that such variation was attributable in part to nutrient imbalance. However, nutrient imbalance is currently diagnosed using critical nutrient ranges that are noisy and biased. Unbiased diagnosis can be performed using the isometric log ratio (ilr) technique for ad hoc balances. Our objective was to present, calibrate, and validate ilr balance standards to diagnose nutrient problems in New Zealand kiwifruit orchards. We collected leaf analytical data [nitrogen (N), sulfur (S), chloride (Cl), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe)] in 433 kiwifruit orchards grown under conventional or organic farming in various agroecological zones of the North Island of New Zealand. Nutrients were arranged into sound balances illustrated by a mobile-fulcrums-buckets metaphor with balance sliders at fulcrums (domain of balances where statistics are computed) and concentrations in buckets (domain of concentrations where nutrient levels are examined relatively to each other). We developed optimum ranges of ilr balances to reach high yield levels and computed a nutrient imbalance predictor as the Mahalanobis distance. The critical Mahalanobis distance was 4.45 ± 0.13 at high yield level (>44 049 ± 334 kg ha^?1), averaged from a five-fold cross-validation test; the test performance was 85 percent using the receiver operating characteristic curve, indicating that the test was informative for diagnostic purposes. After assessing relative nutrient levels in the concentrations domain, the most limiting nutrients appeared to be Cl, Mg, and Fe in poor-yield imbalanced specimens and Cl and S in organic orchards. Indeed, kiwifruit has high demand for Cl. Balance standards should be further tested in field trials.     

苏南地区农田养分循环特征及平衡调控途径

从宏观计算和田间模拟试验两方面分析了江苏南部农田养分循环和平衡特征的变化趋势，农田养分投入结构由有机养分为主转向以无机养分为主，农田养分内循环变弱，农田养分平衡N素由亏损转为过剩，P由亏损转为持衡，但K素亏缺愈加严重。指出增加P、K肥投入，适当控制N肥投入，在机械化条件下增加有机肥的投入是合理调控该地区农田养分平衡的重要途径。     

Balance and concentration of nitrogen and potassium affect growth and nutrient status in soilless cultivated lisianthus

Purpose: Nitrogen (N) / potassium (K) nutrient balance has been studied for some ornamental plants, however, available information is limited. Here we investigate the optimum N and K balance and concentration for lisianthus production in soilless medium.

Materials and methods: The effect of three N / K balances: 1.43, 2.14 and 4.29, prepared by varying the concentration of N and K, were evaluated in lisianthus grown in soilless medium (volcanic rock).

Results: Plants fertigated with a N / K balance of 2.14 exhibited enhanced height and stem dry weight when compared to plants fertigated with a balance of 4.29, and a higher flower buds count and total dry weight than those fertigated with a balance of 1.43 or 4.29. Plants fertigated with a balance of 2.14 exhibited increased dry weight when N was reduced from 15 to 9?meq?L^?1 and K from 7 to 4.2?meq?L^?1, suggesting that lisianthus does not require high levels of these nutrients. Although shoot N concentration was not correlated with N concentration in the nutrient solution or balance, increasing N in the shoot was associated with higher P and Mg in the plant tissues. In general, P, Ca, and Mg in plant tissues were unaffected by the external N / K balance, however, the internal P and Mg concentrations were positively correlated with shoot dry weight. Shoot K concentration significantly increased when the N / K balance decreased, which is related to the higher concentrations of external K when the balance decreased.

Conclusions: The optimum N / K balance for lisianthus was 2.14. However, there was a concentration effect, as fertigation with solutions containing a N / K balance of 2.14 and an N and K concentration of 9 and 4.2?meq?L^?1 respectively, resulted in plants with the greatest dry weight.     

湖北潮土区不同轮作制度下土壤养分平衡状况与评价

通过连续5年定点调查和取样分析,研究了湖北省2个潮土区域农田土壤养分平衡状况,并用允许养分平衡盈亏率进行了评价.结果表明:①在几种主要轮作制中,所有作物的K肥施用量及施用比例均明显比N肥低,但几乎所有作物的K素吸收量均明显高于N素吸收量,早、晚稻吸收P、K的比例明显高于其它作物.②不同轮作制中土壤养分平衡状况表现为N素有不同程度的盈余、P素基本平衡、K素总是亏缺的,且水田K素亏缺量明显高于早地.在此基础上,作者提出"减N稳P增K"和以一个轮作周期为单位进行统筹施肥的养分平衡调控措施,以实现作物生产的高产稳产和土壤养分平衡的良性循环.     

Impact of planted hedgerow fallows on nutrient balances in a groundnut/maize/cassava intercrop

ABSTRACT

To assess if the nutrient supply through planted tree fallows meets crop nutrient uptake and export, N, P, K, Ca and Mg uptake and export by a groundnut/maize/cassava intercrop was compared with the nutrient uptake by three planted fallow systems (Senna spectabilis, Flemingia macrophylla, Dactyladenia barteri) and a no-tree control. Three cycles of two years fallow and one year cropping on Ultisol in southern Cameroon were studied. Fallows were slashed and burned. The fallow system had no consistent effect on nutrient uptake by individual crops. Crop nutrient uptake was most often highest in the S. spectabilis system. Nitrogen balances were generally negative due to N loss in the burn. Across three cropping cycles, the balance of fallow nutrient uptake versus total crop nutrient uptake was only in the S. spectabilis system positive for all nutrients. Nutrient export by all crops (mean of three years) was unaffected by fallow systems. The fallow nutrient uptake versus crop nutrient export balance was positive for all nutrients and systems. Planted fallows appear capable of acquiring sufficient nutrient stocks during fallow phases, covering the crops’ demand. Fallow N and K uptake and crop export declined with every fallow/cropping cycle.     

Characterizing farming systems around Kakamega Forest,Western Kenya,for targeting soil fertility–enhancing technologies

Kakamega district in Western Kenya represents the smallholder farming systems typical for much of the densely populated humid highlands in East Africa. A specific feature, however, is the presence of a protected forest reserve (Kakamega Forest National Park), covering some 20% of the district area. Year‐round crop production with little use of external inputs is resulting in declining soil fertility and crop yields. Technologies to counteract fertility constraints are rarely implemented, as they do not consider system diversity or farm‐specific characteristics. We surmised that farm type–specific targeting of technology options to address soil fertility–related production constraints would reduce the anthropogenic pressure on the resources of the adjacent Kakamega rainforest reserve. Based on Kenyan national census data, we selected 168 farms in physical proximity of the Kakamega forest and characterized them regarding production system and soil attributes. Cluster and principal component analyses identified five distinct farm categories. Three representative farms from each cluster group were subsequently selected to establish labor‐use patterns, draw resource‐flow maps, and determine NPK balances. Small subsistence‐oriented farms were most common (> 50%), with maize yields of 0.9 t ha^–1 (Cluster 1). Most farmers relied on the forest to provide fire wood, animal feed, and medicinal plants. Mixed farms, combining subsistence maize with industrial crops, were differentiated by soil type, with tea being grown on Ferralsol (Cluster 3), and sugar cane being grown on Acrisol (cluster 4). The dependence on forest resources was limited to animal grazing and the collection of feed stuff (Cluster 3), or the extraction of medicinal plants (Cluster 4). Only few farms showed a high degree of market orientation of the food‐crop production. These comprised either small farms with high investments in fertilizer and maize yields close to 2 t ha^–1 (Cluster 2), or larger farms (1.6–3.9 ha) with low fertilizer but high hired‐labor use (Cluster 5). Their reliance on forest resources was generally low. Resource flows showed mainly patterns of nutrient export in subsistence farms, and more complex flow patterns, involving several farm compartments, in the diversified farms. Partial nutrient balances were strongly negative for N and K, irrespective of soil or farm type. Soil‐fertility characteristics reflected the nutrient balances with generally low C and N in all farms on Acrisol, and low P in farms not applying mineral fertilizers or farmyard manure. The proposed typology is expected to improve the targeting of technologies addressing soil fertility–related production constraints, and to reduce the pressure on forest resources. This is of particular importance in the case of small‐scale subsistence and mixed farms close to the forest margin.     

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。     

红壤稻田不同施肥制度对土壤钾平衡和水稻产量的影响

基于14年田间定位试验,研究了红壤稻田系统在不同化肥配施条件下,有机养分循环利用对土壤K素平衡和水稻产量的影响。结果表明:不施肥或仅施化肥,土壤K素严重亏缺,其中以不施K的NP处理最严重,平均每年亏损K120.1kg/hm2,有机物养分循环利用的施肥制度可大幅度降低稻田土壤K素的亏损甚至出现K素盈余,NP C处理平均每年亏损K素2.2kg/hm2,而NPK C处理平均每年盈余K素154.5kg/hm2,但过高的K输入可能导致K营养元素的大量流失,降低K肥资源利用效益并增加环境污染风险,实行有机物养分循环利用时应适当减少化肥K的施用量;在不同施肥基础上的有机物养分循环利用都能显著提高水稻产量,但“循环”增产率随化肥配施程度提高而降低,不施肥基础上有机物养分循环利用的稻谷增产率为56%,与NP配施后,有机物养分循环利用的增产率降至18.8%,而在NPK配施基础上有机物养分循环利用的增产率只有10.2%,处理NPK C2与处理NPK之间的稻谷产量却没有显著差异,可见有机养分循环利用可以代替化肥K的施用;有机养分循环利用降低了K内部利用效率(IKUE)值,大小顺序为NPK C相似文献   

Nutrient flows and balances in intensively managed vegetable production of two West African cities

This study reports and analyzes nutrient balances in experimental vegetable production systems of the two West African cities of Tamale (Ghana) and Ouagadougou (Burkina Faso) over a two‐year period comprising thirteen and eleven crops, respectively. Nutrient‐use efficiency was also calculated. In Tamale and Ouagadougou, up to 2% (8 and 80 kg N ha^?1) of annually applied fertilizer nitrogen were leached. While biochar application or wastewater irrigation on fertilized plots did not influence N leaching in both cities, P and K leaching, as determined with ion‐absorbing resin cartridges, were reduced on biochar‐amended plots in Tamale. Annual nutrient balances amounted to +362 kg N ha^?1, +217 kg P ha^?1, and –125 kg K ha^?1 in Tamale, while Ouagadougou had balances of up to +692 kg N ha^?1, +166 kg P ha^?1, and –175 kg K ha^?1 y^?1. Under farmers' practice of fertilization, agronomic nutrient‐use efficiencies were generally higher in Tamale than in Ouagadougou, but declined in both cities during the last season. This was the result of the higher nutrient inputs in Ouagadougou compared to Tamale and relatively lower outputs. The high N and P surpluses and K deficits call for adjustments in local fertilization practices to enhance nutrient‐use efficiency and prevent risks of eutrophication.