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1.
1980-2015年中国农田生态系统的N素平衡   总被引:5,自引:0,他引:5  
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.  相似文献   

2.
Global nitrogen (N) budgets for intensive agricultural systems were compiled for a 0.5 by 0.5 degree resolution. These budgets include N inputs (N fertilizer, animal manure, biological N fixation and atmospheric N deposition) and outputs (N removal from the field in harvested crops and grass and grass consumption by grazing animals, ammonia volatilization, denitrification and leaching). Data for the historical years 1970 and 1995 and a projection for 2030 were used to study changes in the recovery of N and the different loss terms for intensive agricultural systems. The results indicated that the overall system N recovery and fertilizer use efficiency slowly increased in the industrialized countries between 1970 and 1995, the values for developing countries have decreased in the same period. For the coming three decades our results indicated a rapid increase in both the industrialized and developing countries. High values of > 80% for fertilizer use efficiency may be related to surface N balance deficits, implying a depletion of soil N and loss of soil fertility. The projected intensification in most developing countries would cause a gradual shift from deficits to surpluses in the coming decades. The projected fast growth of crop and livestock production, and intensification and associated increase in fertilizer inputs would cause a major increase in the surface N balance surplus in the coming three decades. This implied increasing losses of N compounds to air (ammonia, nitrous oxide and nitric oxide), and groundwater and surface water (nitrate).  相似文献   

3.
西红柿对聚烯烃控释肥这种新的施肥方法的反应   总被引:2,自引:0,他引:2  
The response of tomato (Lycopersicon esculentum) plants basically fertilized with 0.3 g N per plant of compound fertilizer with a N:P2O5:K2O ratio of 20:10:20 to sticks of polyolefin-coated fertilizer (POCF) (LongT0 with a N:P2Os:K2O ratio of 14:12:14) applied 23 d after transplanting was investigated using rooting boxes in the greenhouse. The results at 26 and 40 d after stick fertilizer treatment showed that the use of the stick fertilizer greatly increased the production of many new fine roots from the tomato plants. Compared to the unfertilized control, root length and root length density in the stick fertilizer treatment increased by 3.6-6.7 fold. In the soil zones near the stick fertilizer, root weight and root mass density were also significantly higher for the stick fertilizer treatment. Additionally, the use of the stick fertilizer increased the N, P and K concentrations in the leaves and stems of the tomato plants. The new fine roots growing near the stick fertilizer not only absorbed more nutrients and translocated them to the shoots, but also contained more nutrients within themselves. The soil ammonium and nitrate N data showed that N released from the stick fertilizer played a major role in inducing the production of new fine roots. These results indicated that stick fertilizer could be used as an alternative to the co-situs application technique to change and control the root distribution of crops as well as to increase the potential capacity of roots for water and nutrient absorption.  相似文献   

4.
在施钾条件下灌溉水稻的养分吸收和利用效率研究   总被引:1,自引:0,他引:1  
HU Hong  WANG Guang-Huo 《土壤圈》2004,14(1):125-130
Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.  相似文献   

5.
Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N,P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.  相似文献   

6.
轮作体系下冬油菜养分利用效率的区域研究   总被引:1,自引:0,他引:1  
Fertilization is essential for oilseed rape because it is sensitivity to nutrient deficiency, especially for winter oilseed rape(Brassica napus L.). To investigate regional nutrient efficiency and nutrient uptake-yield relationship of winter oilseed rape in an intensive cropping system, this study used data from 619 site-year on-farm experiments carried out in the winter oilseed rape planting area of the Yangtze River Basin, China from 2005 to 2010, with large yield in the range of 179–4 470 kg ha~(-1). Currently recommended application rates of N, P and K fertilizers increased rapeseed yield at different levels of soil indigenous nutrient supply(INS) in this region. Boundary values of plant nutrient uptake were established to analyze the nutrient uptake-yield relationship of winter oilseed rape(internal nutrient efficiency), i.e., 128 kg N ha~(-1), 24 kg P ha~(-1), and 122 kg K ha~(-1). The internal nutrient efficiency declined by 48.2%–64.1% when nutrient uptake exceeded the boundary value, resulting in excessive nutrient uptake(i.e., low yield response with high nutrient uptake), especially for K. In the intensive cropping system, agronomic efficiencies of N, P, and K were 5.9, 3.4, and3.6 kg kg~(-1), and recovery efficiencies of N, P, and K were 35.6%, 24.1%, and 36.8%, respectively. These findings showed that the fertilization rate should be optimized by considering INS, nutrient status, and nutrient efficiency of winter oilseed rape. In this study,considering the lower yield improvement to high K uptake levels and low K fertilizer efficiency, application rate of K fertilizer should be reduced since soil K deficiency has already been mitigated.  相似文献   

7.
中国东部精细农业中N肥施用的最新动态和建议   总被引:21,自引:0,他引:21  
The Taihu Region in eastern China is one of China‘s most intensive agricultural regions and also one of the economic ally most developed areas. High nitrogen balance surpluses in the summer rice-winter wheat double-cropping systems are leading to large-scMe non-point source pollution of aquifers. In an interdisciplinary approach, four-year (1995-1998) field trials were carried out in two representative areas (Jurong County and Wuxi City) of the Taihu Region. Five farmers‘ field sites were chosen in each of the 2 locations, with each site divided into “standard“ (farmers‘ practice) and “reduced“ (by 30%-40%) N fertilization. For both fertilization intensities, N balance surpluses and monetary returns from grain sales minus fertilizer expenditures were calculated in an economic assessment. Based on the field trials, the mineral N fertilizer application rates reduced by about 10% for rice and 20%-30% for wheat were recommended in 1999. Since 1999, the research focused on the trends in N fertilizer application rates and changes in grain and agricultural commodities prices. Summer rice N fertilizer use, in Wuxi City as of 2001, dropped by roughly 25%, while for winter wheat it decreased by 10%-20%, compared to the 1995-1998 period. This has been achieved not only by grain policy and price changes, but also by an increased environmental awareness from government officials. Nitrogen balance surpluses in Anzhen Town (of Wuxi City) have consequently diminished by 50%-75% in rice and by up to 40% in wheat, with reductions being achieved without concomitant decreases in physical grain yields or returns from sales minus fertilizer costs.  相似文献   

8.
Over-use of fertilizer in paddy fields could lead to agro-environmental pollution. Therefore, the Paddy Fertilizer Recommendation System (PFRS) application package was designed to aid in the dissemination of fertilizer recommendations for paddy fields. PFRS utilized geographical information system (GIS) ActiveX Controls, enabling the user to select a location of interest linked to a spatial database of paddy field soil characteristics. The application package also incorporated different soil fertilizer recommendation methods, forming a relational database. The application‘s structure conaiated primarily of building database queries using Standard Query Language (SQL) constructed during run-time, baaed on user provided spatial parameters of a selected location, the type of soil desired and paddy production criteria. PFRS, which was comprised of five modules including: File, View, Edit, Layer and Fertilizer/Model, provided the user with map-baaed fertilizer recommendations based on selected soil nutrient P and K map layers as well as N characteristica and land use maps.  相似文献   

9.
A series of field experiments from 1990 to 1994 in Yingtan, Jiangxi Province, were conducted on an upland red soil derived from Quaternary red clay which had been reclaimed three years before the experiments, in order to study the fertility characteristics and fertilizer requirements of the newly reclaimed soil. The field experiments included that on nutrient characteristics and fertilizer effect, that on K-supplying potential and K-Mg relationship, that on fertilization rates of K and N, etc. The newly reclaimed upland soil was low in both N and P, and its responses to nitrogen and phosphate application were very significant. The K-supplying potential was also low, so the soil was highly responsive to K fertilizer. The effect of Ca and Mg fertilizers was not so great for the reason that certain amounts of Ca and Mg were incorporated into the soil through application of calcium magnesium phosphate during land leveling before the experiments. Among the four micronutrients, B, Mo, Zn and Cu, B had the greatest effect on the soil. The fertilizer requirements of the soil were in an order of P and N > K > lime and B > Mg > Mo, Zn and Cu. Eight crops tested had different fertilizer-requiring characteristics. Rapeseed was very sensitive to P and B fertilizers. Barely was especially sensitive to P and lime and it also responded to B, Mo, Zn and Cu. And sweet potato was especially sensitive to K.  相似文献   

10.
江苏省外生菌根真菌资源调查   总被引:16,自引:0,他引:16  
A total of 1400 soil samples from the plow layer (0-20 cm) at an approximate interval of 5 km were collected in the autumn of 2002 over the entire black soil arable crops region to determine the spatial variability of seven variables, such as total organic matter content (OMC), total N, total P, total K, alkali-dissolvable N (AN), available P (AP) and available K (AK), with classical statistics and geostatistical analysis across the entire black soil area in Northeast China. In nonsampled areas ordinary kriging was utilized for interpolation of estimated nutrient determinations. Classical statistics revealed highly significant (P ≤ 0.01) correlations with all seven of the soil properties, except for OMC with AP and total K with AK. In addition, using coefficients of variation, all soil properties, except for total K, were moderately variable. A geostatistical analysis indicated that structural factors, such as parent material, terrain, and water table, were the main causes of the spatial correlations. Strong spatial correlations were noted with OMC, total N, total P, AN, and AP, while they were moderate for total K and AK. The effective spatial autocorrelation of OMC, total N, total P, and AN ranged from 1 037 to 1353 km, whereas the ranges of total K, AP, and AK were only from 6 to 138 km. The fit of the experimental scmi-variograms to the theoretical models indicated that except for AN, kriging could successfully interpolate other six variables. Thns, the geostatistical method used on a large scale could accurately evaluate the spatial variability of most black soil nutrient properties in Northeast China.  相似文献   

11.
湖北潮土区不同轮作制度下土壤养分平衡状况与评价   总被引:4,自引:0,他引:4  
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.  相似文献   

12.
环渤海低平原农田生态系统养分循环与平衡研究   总被引:7,自引:2,他引:5  
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。  相似文献   

13.
N, P and K budgets for crop rotations on nine organic farms in the UK   总被引:2,自引:0,他引:2  
Abstract. Nitrogen (N), phosphorus (P) and potassium (K) budgets were calculated for nine organic farms in the UK. The farms were situated on sandy loams, silty clay loams and silty loams over chalk with stockless farming systems and cattle, pig and poultry enterprises with a significant proportion of arable cropping. A soil surface nutrient budget was calculated for the target rotation on each farm using information about field management and measurements of the soil, crops and manure. Losses of N through leaching and volatilization were calculated independently using the nitcat and manner models. Nutrient budgets for seven of the farm rotations showed an N surplus, six a P surplus and three a K surplus. The ratio of N inputs supplied in the form of biological fixation : manure : atmospheric deposition was approximately 2 : 2 : 1 for stocked systems and 2 : 0 : 1 for stockless systems. Phosphorus surpluses resulted from supplementary P fertilizer (rock phosphate) and additional feed for non-ruminant livestock. The stockless system without P fertilizer resulted in a large P deficit and stocked systems, which relied on recycling manure alone, a small P deficit. Only rotations with large returns of manure or imported feed showed a K surplus or a balanced K budget.  相似文献   

14.
为科学测度粮食主产区耕地保护外部性盈余/赤字,论文基于耕地保护外部性多层次边界,构建了省级边界和全国边界下典型区域耕地保护外部性盈余/赤字测度模型,并以河南省18个地市为研究区域展开实证分析。结果表明:(1)同一边界下河南省各地市耕地保护外部性盈余/赤字空间分布差异性明显。省级边界下,河南省耕地保护外部性盈余区和赤字区各有9个地市,整体表现为西北部处于赤字区,东北部处于轻度盈余区,西南部处于中高度盈余区。全国边界下,随着人均粮食消费量标准的提高,耕地保护外部性盈余区数量比重降低、赤字区数量比重加大。在人均粮食消费量为380 kg、400 kg、420 kg和435 kg标准下,耕地保护外部性盈余区(地市)数量占比分别为88.89%、83.33%、77.78%和72.22%。(2)多层次作用边界下河南省各地市耕地保护外部性盈余/赤字空间分布差异性明显。具体表现为:同一地市从省级边界到全国边界下耕地保护外部性赤字减弱、盈余增强,或由赤字区转变为盈余区。总之,未来研究应依据不同作用边界下耕地保护外部性盈余/赤字的空间分布规律,结合主体功能区划,构建多层次一体化的耕地保护经济补偿体系,科学界定耕地保护经济补偿的接受区和给付区,制定科学的耕地保护区际经济补偿标准。  相似文献   

15.
The nitrogen, phosphorus and potassium balances for agriculture in Germany during the period 1970 to 1995 (western states) and 1990 to 1995 (entire Germany including the states of the former German Democratic Republic), respectivly, are calculated according to the PARCOM guidelines. The surplus of the basic national mineral balance is subdivided into the crop production surplus and the livestock production balance surplus. In the former West German states, P and K basic surpluses have declined about 60% since 1980, while the N-surplus has dropped 23% since 1987. The efficiency of agricultural nutrient use has improved correspondingly. A sensitivity analysis and an error estimation reveal the accuracy of the results. The relevance and limits of interpreting nutrient balances on a national scale are clarified by a critical appraisal of the balance surplus values.  相似文献   

16.
Abstract

At the moment, Hungarian agriculture is confronted with a certain duality as far as nutrients are concerned. On the one hand, national soil nutrient balances show substantial deficits, and on the other hand, agricultural nutrient use is responsible for a part of the nitrogen (N) and phosphorus (P) losses to the environment. To understand this duality and help optimize farm nutrient management, the farm gate N and P balances of 12 farms, representing a variety of Hungarian agriculture, were calculated for the year 2002. The farm gate N and P surpluses/deficits in the east of the country were lower than in the west. This was correlated with a lower fertilization rate. The low soil fertility level due to a prolonged period of low fertilization in combination with continuing nutrient deficits can lead to possible future reduction in crop yields.  相似文献   

17.
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.  相似文献   

18.
红壤稻田不同施肥制度对土壤钾平衡和水稻产量的影响   总被引:5,自引:1,他引:4  
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   

19.
当前我国农业生产中的养分需求分析   总被引:10,自引:6,他引:4  
【目的】估算当前我国不同区域农业生产中的养分需求和化肥需求,对如何实现2020年化肥零增长以及零增长下如何进行养分资源的合理分配、科学管理和施用具有重要的指导意义和参考价值。【方法】本研究依据国家统计最新数据、研究结果和文献资料,以省级为单元,系统估算了农作物、林地、草地、水产养殖全面实现平衡施肥条件下对氮磷钾养分的需求量。在考虑有机肥养分有效还田基础上,分析当前化肥消费量与化肥需求量的差异。【结果】当前我国农业生产需要氮磷钾养分共8410万t,其中N 3746万t、P2O5 2024万t、K2O 2640万t,粮食作物、蔬菜/瓜果、果树和茶叶、油料作物、纤维作物、糖料作物、饲草/草地、水产养殖的养分需求分别占总需求的41.8%、20.8%、13.1%、5.1%、2.3%、2.1%、10.6%和2.2%。华北、长江中下游、西北、西南、东南、东北地区的养分需求分别占20.3%、23.2%、18.8%、16.8%、11.1%和9.8%,其中山东、河南和四川对养分的需求高于其他省份。当前全国化肥消费量为6023万t,其中N、P2O5、K2O分别为3001万t、1943万t和1079万t,东北、华北、长江中下游、东南、西南、西北地区的化肥消费量分别占全国化肥消费量的10.6%、27.7%、24.4%、11.5%、11.4%、14.2%。我国当前有机肥养分资源潜力为N 3200万t、P2O5 1440万t和K2O 3400万t,但还田的有效养分约为N 484万t、P2O5 411万t和K2O 1273万t。有机肥还田主要在河北、河南、山东、四川和湖南省,其次是广东、广西、云南,而西北、东北及东南沿海地区各省有机肥还田的有效养分量相对较少。化肥消费与需求差表明,全国氮肥和钾肥供应不足,分别亏缺约N 261万t和K2O 288万t,而磷肥投入过量约P2O5 330万t。但不同省份和区域间化肥供需具有较大差异,东北、华北、长江中下游或东南地区的一些省份如吉林、河北、河南、山东、安徽、江苏、湖北、广东省氮磷钾肥均过量,而西北和西南地区多数省份的化肥投入不足。【结论】粮食作物是养分需求的主体,其次是蔬菜和果树。在全面实现平衡施肥的情况下,氮、钾肥投入不足,磷肥投入过量。养分需求地区间差异明显,东北、华北、长江中下游和东南沿海地区需适当减少肥料消费,而西北和西南地区需要依据需求适量增加肥料的投入。  相似文献   

20.
Abstract

Results of 240 annual N fertilizer trials in 1991–2007 in spring and winter cereals are presented. On average, spring barley and oat yields increased little beyond 120 kg N ha?1 in fertilizer. Somewhat higher figures were found for spring and winter wheat. Regression equations for yield and N uptakes in grain and straw were derived, related to N fertilizer input and the yield level in individual trials (indicator of yield expectancy). These equations accounted for 90% of the variation in yield and 80% of that in N uptake. Quadratic N responses were significant in all cases, as were interactions between N responses and yield level. They were verified with data from 27 separate trials performed in 2008–2010. The yield equations were used to calculate economically optimum N fertilizer levels with varying ratios of product price to fertilizer cost at contrasting levels of yield. The optimum N fertilizer level for barley and oats was found to increase by 8.3 kg N ha?1 per Mg increase in expected yield. The equivalent figure in wheat was 16.3 kg N ha?1. Optimum N fertilizer levels decreased by 4.1 and 6.7 kg N ha?1, for barley/oats and wheat respectively, per unit increase in the cost/price ratio. The equations for N uptake were used to calculate simple N balances between fertilizer input and removal in crop products. Large N surpluses were indicated at low levels of yield expectancy, but the surplus declined markedly with increasing yield level, despite greater N fertilizer inputs at high yield. Calculations made for national average yield levels in recent years showed N surpluses of 50–60 kg N ha?1 when only grain is removed and 25–40 kg N ha?1 when straw is removed also. Limiting N input to obtain zero balance reduces yields considerably at average levels of yield expectancy.  相似文献   

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