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1.
太湖地区水稻最适宜施氮量研究   总被引：4，自引：0，他引：4  
To determine the optimal amount of nitrogen(N) fertilizer for achieving a sustainable rice production at the Taihu Lake region of China,two-year on-farm field experiments were performed at four sites using various N application rates.The results showed that 22%-30% of the applied N was recovered in crop and 7%-31% in soils at the rates of 100-350 kg N ha 1.Nitrogen losses increased with N application rates,from 44% of the applied fertilizer N at the rate of 100 kg N ha 1 to 69% of the N applied at 350 kg N ha 1.Ammonia volatilization and apparent denitrification were the main pathways of N losses.The N application rate of 300 kg N ha 1,which is commonly used by local farmers in the study region,was found to lead to a significant reduction in economic and environmental efficiency.Considering the cost for mitigating environmental pollution and the maximum net economic income,an application rate of 100-150 kg N ha 1 would be recommended.This recommended N application rate could greatly reduce N loss from 199 kg N ha 1 occurring at the N application rate of 300 kg N ha 1 to 80-110 kg N ha 1,with the rice grain yield still reaching 7 300-8 300 kg DW ha 1 in the meantime.  相似文献   

2.
中国南方大棚蔬菜地氮平衡与损失   总被引：28，自引：0，他引：28  
High rates of fertilizer nitrogen (N) are applied in greenhouse vegetable fields in southeastern China to maximize production;however,the N budgets of such intensive vegetable production remain to be explored.The goal of this study was to determine the annual N balance and loss in a greenhouse vegetable system of annual rotation of tomato,cucumber,and celery at five N (urea) application rates (0,348,522,696,and 870 kg N ha-1 year-1).Total N input to the 0-50 cm soil layer ranged from 531 to 1 053 kg ha-1,and N fertilizer was the main N source,accounting for 66%-83% of the total annual N input.In comparison,irrigation water,wet deposition,and seeds in total accounted for less than 1% of the total N input.The fertilizer N use efficiency was only 18% under the conventional application rate of 870 kg N ha-1 and decreased as the application rate increased from 522 to 870 kg N ha-1.Apparent N losses were 196-201 kg N ha-1,of which 71%-86% was lost by leaching at the application rates of 522-870 kg N ha-1.Thus,leaching was the primary N loss pathway at high N application rates and the amount of N leached was proportional to the N applied during the cucumber season.Moreover,dissolved organic N accounted for 10% of the leached N,whereas NH3 volatilization only contributed 0.1%-0.6% of the apparent N losses under the five N application rates in this greenhouse vegetable system.  相似文献   

3.
利用叶绿素仪和叶色卡实施旱直播稻田的实地氮肥管理   总被引：3，自引：0，他引：3  
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4.
Cover crop and nitrogen(N) fertilization may maintain soil organic matter under bioenergy perennial grass where removal of aboveground biomass for feedstock to produce cellulosic ethanol can reduce soil quality. We evaluated the effects of cover crops and N fertilization rates on soil organic carbon(C)(SOC), total N(STN), ammonium N(NH_4-N), and nitrate N(NO_3-N) contents at the0–5, 5–15, and 15–30 cm depths under perennial bioenergy grass from 2010 to 2014 in the southeastern USA. Treatments included unbalanced combinations of perennial bioenergy grass, energy cane(Saccharum spontaneum L.) or elephant grass(Pennisetum purpureum Schumach.), cover crop, crimson clover(Trifolium incarnatum L.), and N fertilization rates(0, 100, and 200 kg N ha~(-1)). Cover crop biomass and C and N contents were greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1) than in the treatment of energy cane and elephant grass. The SOC and STN contents at 0–5 and 5–15 cm were 9%–20% greater in the treatments of elephant grass with cover crop and with or without 100 kg N ha~(-1)than in most of the other treatments. The soil NO_3-N content at 0–5 cm was 31%–45% greater in the treatment of energy cane with cover crop and 100 kg N ha~(-1)than in most of the other treatments.The SOC sequestration increased from 0.1 to 1.0 Mg C ha~(-1)year~(-1)and the STN sequestration from 0.03 to 0.11 Mg N ha~(-1)year~(-1)from 2010 to 2014 for various treatments and depths. In contrast, the soil NH_4-N and NO_3-N contents varied among treatments,depths, and years. Soil C and N storages can be enriched and residual NO_3-N content can be reduced by using elephant grass with cover crop and with or without N fertilization at a moderate rate.  相似文献   

5.
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   

6.
The management of fertilizer application is crucial for agricultural production and environmental safety.The objective of this study was to assess the effciency of different fertilization strategies,applying fertilizers with and without nitrification inhibitors(NIs) in split application,in Greece.The assessment criteria used were based on crop yield,soil nitrogen(N)concentrations and economic effciency.For this purpose two crops(winter wheat and cotton)were seffected in order to explore the optimum fertilization strategy for each crop.Three treatments combining fertilizers with NIs were tested compared with conventional fertilization(CF).Slight differences in the quantity and the combination of fertilizers with NIs applied resulted in variable effects on crop yield,soil N and economic return.Split N application of 102 kg ha-1,with half of the total amount applied at seeding,resulted in higher grain yield of winter wheat,lower NO3--N in soil and higher economic return.This result reveals the importance of N application at seeding in wheat crop.Fertilization strategy with 109.5 kg N ha-1 and split P application resulted in higher cotton yield and higher economic profit.Split P application seemed to increase yield,even though it is not a common practise in the area.  相似文献   

7.
Yield and N uptake of tomato (Lycopersicum esculentum Mill.) and pepper (Capsicum annuum L.) crops in five successive rotations receiving two compound fertilizers (12-12-17 and 21-8-11 N-P2O5-K2O) were studied to determine 1) crop responses, 2) dynamics of NO3-N and NH4-N in different soil layers, 3) N balance and 4) system-level N efficiencies. Five treatments (2 fertilizers, 2 fertilizer rates and a control), each with three replicates, were arranged in the study. The higher N fertilizer rate, 300 kg N ha-1 (versus 150 kg N ha-1), returned higher vegetable fruit yields and total aboveground N uptake with the largest crop responses occurring for the low-N fertilizer (12-12-17) applied at 300 kg N ha-1 rather than with the high-N fertilizer (21-8-11). Ammonium-N in the top 90 cm of the soil profile declined during the experiment, while nitrate-N remained at a similar level throughout the experiment with the lower rate of fertilizer N. At the higher rate of N fertilizer there was a continuous NO3-N accumulation of over 800 kg N ha-1. About 200 kg N ha-1 was applied with irrigation to each crop using NO3-contaminated groundwater. In general, about 50% of the total N input was recovered from all treatments. Pepper, relative to tomato, used N more efficiently with smaller N losses, but the crops utilized less than 29% of the fertilizer N over the two and a half-year period. Local agricultural practices maintained high residual soil nutrient status. Thus, optimization of irrigation is required to minimize nitrate leaching and maximize crop N recovery.  相似文献   

8.
中国太湖地区稻麦轮作农田硝态氮动态与氮素平衡   总被引：1，自引：0，他引：1  
Nitrate-nitrogen (NO 3--N) dynamics and nitrogen (N) budgets in rice (Oryza sativa L.)-wheat (Triticum aestivum L.) rotations in the Taihu Lake region of China were studied to compare the effects of N fertilizer management over a two-year period. The experiment included four N rates for rice and wheat, respectively: N1 (125 and 94 kg N ha-1 ), N2 (225 and 169 kg N ha-1 ), N3 (325 and 244 kg N ha-1 ), and N0 (0 kg N ha-1 ). The results showed that an overlying water layer during the rice growing seasons contributed to moderate concentrations of NO 3--N in sampled waters and the concentrations of NO 3--N only showed a rising trend during the field drying stage. The NO 3--N concentrations in leachates during the wheat seasons were much higher than those during the rice seasons, particularly in the wheat seedling stage. In the wheat seedling stage, the NO 3--N concentrations of leachates were significantly higher in N treatments than in N0 treatment and increased with increasing N rates. As the NO 3--N content (below 2 mg N L-1 ) at a depth of 80 cm during the rice-wheat rotations did not respond to the applied N rates, the high levels of NO 3--N in the groundwater of paddy fields might not be directly related to NO 3--N leaching. Crop growth trends were closely related to variations of NO 3--N in leachates. A reduction in N application rate, especially in the earlier stages of crop growth, and synchronization of the peak of N uptake by the crop with N fertilizer application are key measures to reduce N loss. Above-ground biomass for rice and wheat increased significantly with increasing N rate, but there was no significant difference between N2 and N3. Increasing N rates to the levels greater than N2 not only decreased N use efficiency, but also significantly increased N loss. After two cycles of rice-wheat rotations, the apparent N losses of N1, N2 and N3 amounted to 234, 366 and 579 kg N ha-1 , respectively. With an increase of N rate from N0 to N3, the percentage of N uptake in total N inputs decreased from 63.9% to 46.9%. The apparent N losses during the rice seasons were higher than those during the wheat seasons and were related to precipitation; therefore, the application of fertilizer should take into account climate conditions and avoid application before heavy rainfall.  相似文献   

9.
施用控释肥提高直播水稻氮的利用率   总被引：4，自引：0，他引：4  
Field trials on a silt-loamy paddy soil derived from shallow-sea deposit in direct seeding rice fields were conducted in Zhejing ,China,in 1996 to compare N efficiency of controlled release fertilizers (LP fertilizers) with the conventional urea.Six treatments including CK (no N fertilizer),conventional urea and different types of LP fertilizers at different rates were designed for two succeeding crops of early and late rice.A blend of different types of LP fertilizers as a single preplant “co-situs“ application released n in a rate and amount synchronizing with uptake pattern of direct seeding rice.A single preplant application of the LP fertilizers could meet the N requirement of rice for the whole growth period without need of topdressing,Using LP fertilizer blends ,equivalent grain yields could be maintained even if the N fertilization rates were reduced by 25%-50% compared with the conventional urea .Agronomi efficiency of the LP fertilizers was 13.6%-86.4% higher than that of the conventional urea in early rice and 100%-164.1% in late rice,depending on the amounts of the LP fertilizers applied.N fertilizer recovery rate incereased from 27.4% for the conventional application of urea to 41.7%-54.1%,for the single preplant “co-situs“ application of the LP fertilizers,Use of the LP fertilizers was promising if the increse in production costs due to the hihg LP fertilizer prices could be compensated by increase in yield and N efficiency,reduction in labor costs and improvement in environment.  相似文献   

10.
氮肥施用对冬小麦籽粒产量和氮素表观损失的影响   总被引：16，自引：0，他引：16  
Excessive nitrogen （N） fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content （Nmin） in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels （average 212 kg N ha^-1）. The average optimum N rate was 96 kg N ha^-1 for the five sites with low initial soil Nmin （average 155 kg N ha^-1） before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha^-1, whereas the farmers＇ conventional N application rate resulted in losses of more than 100 kg N ha^-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields.  相似文献   

11.
Abstract

Excessive use of nitrogen (N) fertilizers in wheat fields has led to elevated NO3-N concentrations in groundwater and reduced N use efficiency. Three-year field and 15N tracing experiments were conducted to investigate the effects of N application rates on N uptake from basal and topdressing 15N, N use efficiency, and grain yield in winter wheat plants; and determine the dynamics of N derived from both basal and topdressing 15N in soil in high-yielding fields. The results showed that 69.5–84.5% of N accumulated in wheat plants derived from soil, while 6.0–12.5%and 9.2–18.1% derived from basal 15N and top 15N fertilizer, respectively. The basal N fertilizer recovery averaged 33.9% in plants, residual averaged 59.2% in 0–200 cm depth soil; the topdressing N fertilizer recovery averaged 50.5% in plants, residual averaged 48.2% in 0–200 cm soil. More top 15N was accumulated in plants and more remained in 0–100 cm soil rather than in 100–200 cm soil at maturity, compared with the basal 15N. However, during the period from pre-sowing to pre-wintering, the soil nitrate moved down to deeper layers, and most accumulated in the layers below 140 cm. With an increase of N fertilizer rate, the proportion of the N derived from soil in plants decreased, but that derived from basal and topdressing fertilizer increased; the proportion of basal and top 15N recovery in plants decreased, and that of residual in soil increased. A moderate application rate of 96–168 kg N ha?1 led to increases in nitrate content in 0–60 cm soil layer, N uptake amount, grain yield and apparent recovery fraction of applied fertilizer N in wheat. Applying above 240 kg N ha?1 promoted the downward movement of basal and top 15N and soil nitrate, but had no significant effect on N uptake amount; the excessive N application also obviously decreased the grain yield, N uptake efficiency, apparent recovery fraction of applied fertilizer N, physiological efficiency and internal N use efficiency. It is suggested that the appropriate application rate of nitrogen on a high-yielding wheat field was 96–168 kg N ha?1.  相似文献   

12.
ABSTRACT

In order to formulate a nitrogen (N) management strategy under continuous full amount of straw returning (CFSR) for double cropping rice production, long-term (2013–2016) paddy field experiments were conducted in double cropping rice production area in the Jiangxi province, China. Five N fertilizer treatments under CFSR were tested, that is, (i) no N fertilizer application (CK); (ii) conventional N fertilizer application (165kg N ha?1 and 195 kg N ha?1 in early and late rice variety with the ratio of basal dressing to topdressing as 6:4, respectively) (CNF6:4); (iii) recommended N fertilizer application (135 kg ha?1 N and 165 kg ha?1 N in early and late rice variety with the ratio of basal dressing to topdressing as 4:6, 6:4, and 8:2, respectively) (RNF4:6, RNF6:4, and RNF8:2). Nitrogen fertilizer treatments under CFSR had 5.70% and 8.93% higher soil total nitrogen (TN), 1.32% and 0.80% higher available nitrogen (AN), 16.55% and 22.94% higher NH4+-N, and 13.10% and 7.93% higher NO3--N than CK treatments in early and late rice variety, respectively. There were no differences in soil TN, AN, NH4+-N, and NO3--N contents between CNF6:4 and RNF6:4 treatments, while CNF6:4 treatment showed higher or significantly higher soil N contents than RNF4:6 and RNF8:2 treatments. N fertilizer treatment under CFSR showed 88.9% and 43.20% higher grain yield and 62.15% and 42.52% higher panicle numbers than CK treatments in early and late rice variety, respectively. Compared with CNF6:4, RNF treatments did not significantly reduce grain yield and yield components in early and late rice variety, respectively, except for RNF8:2. Compared with RNF6:4 and 8:2, RNF4:6 showed higher rice grain yield, while no obvious differences in yield components were obtained among all RNF treatments. We concluded that N fertilizer under CFSR was helpful to improve soil N contents and double rice grain yield and panicle numbers. Appropriate reduction of N application (18% and 15% reduction in early and late rice variety, respectively) on the basis of adjusting ratio of basal dressing to topdressing as 4:6 and 6:4 did not significantly reduce soil TN and double rice grain yield and yield components, especially, the 40% basal N dressing and 60% N topdressing was beneficial to increase double rice grain yield under CFSR.  相似文献   

13.
研究了不同氮肥运筹对土壤硝态氮时空分布及小麦氮肥利用效率的影响。结果表明,小麦氮素利用效率随施氮量的增加而显著降低,增加追肥比例提高了产量和氮肥利用效率,品种间趋势一致。0～60 cm土层土壤硝态氮含量冬前最高,随着生育进程而逐渐降低。随施氮量增加土壤硝态氮含量升高,特别是下层土壤硝态氮含量在施氮处理下更为明显。从播种至成熟,不施氮处理土壤氮素出现了表观亏缺,施氮处理均表现氮素盈余,且随施氮量的增加而增加。因此,在小麦生产中应避免在播种时一次性大量施用氮肥,而分期施肥有利于小麦吸收利用,并且可以减少深层土壤硝态氮的累积。  相似文献   

14.
Nitrogen and weeds are two important factors that influence the productivity of rainfed upland rice (Oryza sativa L.) in tropical Asia. A low recovery of applied fertilizer N in rainfed uplands is generally associated with high nitrate leaching losses and weed interferences. Field experiments were conducted during the wet seasons of 2002 and 2003 at the research farm of Central Rainfed Upland Rice Research Station, Hazaribag, Jharkhand, India, to determine the response of upland rice to nitrogen applied at 60 kg N ha–1 as different forms of urea (single pre‐plant application of controlled‐release urea, single pre‐plant application of urea supergranules, and split application of prilled urea with or without basal N) against no N application under three weed‐control regimes (unweeded, pre‐emergence application of butachlor at 1.5 kg a.i. ha–1 supplemented with one single hand weeding or two hand weedings). The response of rice to applied N varied greatly among the three weed‐control regimes. Across the different N treatments, the application of 60 kg N ha–1 resulted in a grain‐yield increase above the unfertilized control of only 0.24 Mg ha–1 in unweeded treatments, whereas yields increased by 1.07 Mg ha–1 when butachlor application was supplemented with a single hand weeding and by 1.28 Mg ha–1 with two hand weedings. Among the weed‐control measures, hand weeding twice produced highest grain yield in both years. The comparison of different forms of urea showed that a single pre‐plant application of controlled‐release urea resulted in average grain yields of 1.57 and 1.87 Mg ha–1 compared to 1.32 and 1.30 Mg ha–1 in the case of the recommended practice of split‐applied prilled urea in the years 2002 and 2003, respectively. The highest agronomic N use efficiency of 15–20 kg grain per kg N applied and the highest apparent N recovery of 39%–45% were attained with controlled‐release urea, suggesting that this N form is particularly beneficial for upland‐rice cultivation under variable rainfall conditions, provided weeds are controlled.  相似文献   

15.
以中筋小麦济麦22为试材,在小麦拔节期和开花期0—40cm土层土壤相对含水量均补灌至70%和总施氮量为240kg/hm~2条件下,设置5个氮肥基追比例处理:0∶10(N1)、3∶7(N2)、5∶5(N3)、7∶3(N4)、10∶0(N5),研究测墒补灌节水栽培条件下氮肥基追比例对小麦植株氮素利用和土壤氮素表观盈亏的影响。结果表明:N3处理的植株氮素积累量、籽粒氮素积累量显著高于其他基追比例处理;营养器官氮素积累量、土壤矿质氮损失量、氮肥表观残留率和氮肥表观损失率显著低于其他处理。与N1、N2、N4、N5处理相比,N3处理的氮素生理利用率分别高33.22%,12.60%,11.54%,98.14%,籽粒氮素利用率高148.65%,56.48%,59.63%,229.29%,氮肥农学效率高96.52%,34.86%,37.64%,204.98%,氮素表观盈亏量分别低35.04%,13.82%,30.36%,29.30%。根据不同氮肥基追比例下各指标的相关系数分析表明,植株氮素积累量、籽粒氮素积累量、氮素生理利用率、籽粒氮肥利用率、氮肥农学效率与土壤硝态氮积累量、成熟期0—200cm土层土壤矿质氮残留总量均呈显著负相关。综上,氮肥基追比例为5∶5的N3处理为试验条件下的最优处理。  相似文献   

16.
Controlled-release urea (CRU) and its placement method in rice production were investigated during 2007 and 2008 seasons. Controlled-release urea was applied at 62.5, 125, and 187.5 kg nitrogen (N) ha?1, and the urea was 187.5 kg N ha?1. All the CRU treatments were applied to the nursery beds once, and they were brought into the paddy field during transplanting, while the urea treatment was split into three applications from the plowing to the harvest. The results showed that rice seedlings with CRUs germinated and grow well and there was no salt damage at the nursery stage. The CRU treatment with 125 kg N ha?1 had 33% less N than urea treatment (187.50 kg N ha?1), but it produced significantly higher grain and straw yields, higher total N uptake and total apparent N uptake efficiency. In addition, all the CRU treatments effectively decreased floodwater ammonium (NH4 +)-N and nitrate (NO3 ?)-N concentrations, pH, and N runoff.  相似文献   

17.
Leaf color chart (LCC) guides fertilizer nitrogen (N) application to rice as per requirement of the crop on the basis of a critical leaf color. Two field experiments were conducted to evaluate the effect of silicon (Si) and LCC based N management in aerobic rice. Following LCC-based N management, from 60 to 90 kg N ha?1 and 75 to 100 kg N ha?1 with 10–40% and 25–30% less fertilizer N was used without any reduction in yield as compared to the package of practices of 100 (50 kg N ha?1 as basal + two split of 25 kg N ha?1) kg N ha?1 respectively, during both the seasons. The highest grain yield was noticed with 90 kg N ha?1 (30 kg N ha?1 as basal + LCC-3) and 100 kg N ha?1 (50 kg N ha?1 as basal + two split of 25 kg N ha?1) along with the application of calcium silicate (CaSiO3) at 2 t ha?1 as sources of Si and on par with 60 kg N ha?1 (no basal + LCC-3) and 75 kg N ha?1 (30 kg N ha?1 as basal + LCC-3), respectively, during the season in 2008 and 2009. Higher fertilizer N use efficiency was recorded with Si and need-based N management using LCC-3 rather than recommended dose of fertilizer N.  相似文献   

18.
Dry direct-seeded aerobic rice (DSR) is an emerging attractive alternative to traditional puddled transplanted rice (PTR) production system for reducing labour and irrigation water requirements in the Indo-Gangetic plains (IGP) of India. The fertilizer N requirement of DSR grown with alternate wetting and drying water management may differ from that of PTR grown under continuous flooding due to differences in N dynamics in the soil/water system and crop growth patterns. Limited studies have been conducted on optimizing N management and application schedule for enhanced N use efficiency in DSR. Therefore, field experiments were conducted over 3 years in NW India to evaluate the effects of N rate and timing of its application on crop performance and N use efficiency. Interaction effects of four N rates (0, 120, 150, and 180 kg ha?1) as urea and four schedules of N application on yield and N use efficiency were evaluated in DSR. The N schedules included N application in three equal split doses (0, 35 and 63, and 14, 35 and 63 days after sowing, DAS) and four equal split doses (0, 28, 49 and 70; 14, 28, 49 and 70 DAS). There was no significant interaction between N rate and schedules on grain yield. Significant response to fertilizer N was observed at 120 kg N ha?1 and economic optimum dose for three equal split doses and skipping N at sowing was 130 kg N ha?1. Highest mean grain yield of 6.60 t ha?1 was obtained when N was applied in three equal split doses at 14, 35 and 63 DAS which was about 8.5% higher compared with N applied in four equal split doses at 14, 28, 49 and 70 DAS. Under the best N application schedule, agronomic N use efficiency (26 kg grain kg?1), recovery efficiency (49%) and physiological efficiency (53 kg kg?1) were comparable to the values reported in Asia for PTR. Results from our study will help to achieve high yields and N use efficiency in DSR to replace resource intensive PTR.  相似文献   

19.
【目的】黄河流域棉区是我国三大棉区之一,氮肥管理在棉花生产中至关重要,氮肥供应不足或过量会影响棉花的皮棉产量和纤维品质,过量施氮可能导致棉花营养生长过旺,产量下降,也会造成不必要的浪费及棉田环境污染,氮肥供应不足会导致棉花生物量较小,皮棉产量降低,纤维品质下降。本文通过3年不同氮肥用量的田间小区定位试验,研究施氮量对棉花功能叶生理特性、氮素利用效率及籽棉产量的影响,旨在探讨黄河流域棉区华北平原亚区中等肥力棉田适宜施氮量,揭示棉花氮素高效利用的相关机理。【方法】田间试验于2011 2013年在河南安阳县中棉所试验农场进行,供试田块为多年连作棉田,土壤为壤质潮土,2011年播种前0—20 cm土层土壤有机质、全氮、速效氮(N)、速效磷(P)、速效钾(K)含量分别为11.24 g/kg、0.82 g/kg、77.43 mg/kg、16.69 mg/kg、129.82 mg/kg。以转Bt+Cp TI中熟棉花品种中棉所79为材料,采用随机区组设计,重复4次,设置0、90、180、270、360、450 kg/hm26个施氮水平,氮肥底施和初花期追施各半,磷(P2O5)、钾(K2O)全部底施,施用量均为120kg/hm2。试验小区长10 m,宽4.8米,每小区6行棉花,种植密度57500 plant/hm2。2011年4月17日播种,2012年4月25日播种,2013年5月3日播种。2013年研究了施氮量对初花期棉花功能叶光合速率、不同生育期棉花群体叶面积指数(LAI)、不同生育期棉花功能叶叶绿素含量、丙二醛(MDA)含量、谷氨酰胺合成酶(GS)活性的影响,2012、2013年研究了施氮量对棉花氮素内在利用率、氮肥农学利用率、氮素生理利用率、氮肥回收率及籽棉产量的影响。【结果】随施氮量的增加,不同生育期棉花群体LAI、功能叶叶绿素含量、GS活性、初花期棉花功能叶净光合速率呈增加的趋势,而功能叶MDA含量呈下降趋势。施氮量270、360 kg/hm2处理棉花在盛铃期群体LAI较适宜,吐絮期棉花功能叶能维持较高的生理活性,可为棉花高产提供物质保障。棉花氮素积累量、籽棉产量与施氮量间均呈二次曲线关系,棉花氮肥农学利用率和氮素内在利用率随施氮量增加显著下降,施氮量超过180 kg/hm2时氮素生理利用率下降,施氮量为270 kg/hm2时氮肥回收率高于其他处理。施氮量360 kg/hm2时,籽棉平均产量最高,显著高于施氮量为0、90 kg/hm2的处理,但与施氮量180、270、450 kg/hm2处理间差异不显著。棉花3年籽棉平均产量(Y)与施氮量(N)的效应方程为Y=3143.8036+4.2057N-0.006220N2(R2=0.9805,P=0.002717);棉花的最高产量施氮量为338.1 kg/hm2,经济最佳施氮量为299.7 kg/hm2。【结论】黄河流域棉区华北平原亚区中等肥力棉田施氮量超过270 kg/hm2时,棉花氮肥农学利用率、氮素内在利用率、氮素生理利用率、氮肥回收率开始下降,该区棉田推荐经济施氮量299.7 kg/hm2。  相似文献   

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