Effect of Nitrogen Applied Before Transplanting on NUE in Rice

Nitrogen （N） application before transplanting, where N fertilizers are applied in seedling-bed and carried to the paddy field with seedlings, is a novel method proposed in this article aiming for improving nitrogen utilization efficiency （NUE） in rice. The effect of this method on mineral N distribution in the rhizosphere soil was investigated in a field experiment with a japonica variety, Ningjing 2, in seasons of 2004 and 2005. There were four levels of N applied 16 h before transplanting： zero N （NO）, 207 kg ha^-1 （NL）, 310.5 kg ha^-1 （NM）, and 414 kg ha^-1 （NH）. The result indicated that N fertilizer before transplantation had positive effect of increasing mineral N content in the rhizosphere soil of rice. Generally, N content in the rhizosphere soil of rice tended to increase with the amount of N fertilizer before transplanting, with the NH treatment having the largest effect. Additionally, N fertilizer before transplanting had significant influence on rice NUE and grain yield. Compared with other treatments, the NM treatment showed the largest influence, with basal-tillering NUE, total NUE, and grain yield being 15%, 12%, and 529.5 kg ha^-1 higher than those of NO treatment. This result indicated that N fertilizer before transplantation had positive effect on mineral N distribution in the rhizosphere soil of rice, thus improving NUE and grain yield.     

Study of Dynamics of Floodwater Nitrogen and Regulation of Its Runoff Loss in Paddy Field-Based Two-Cropping Rice with Urea and Controlled Release Nitrogen Fertilizer Application

The article deals with the effects of urea and controlled release nitrogen fertilizer （CRNF） on dynamics of pH, electronic conductivity （EC）, total nitrogen （TN）, NH4^＋-N and NO3 -N in floodwater, and the regulation of runoff TN loss from paddy field-based two-cropping rice in Dongting Lake, China, and probes the best fertilization management for controlling N loss. Studies were conducted through modeling alluvial sandy loamy paddy soil （ASP） and purple calcareous clayey paddy soil （PCP） using lysimeter, following the sequence of the soil profiles identified by investigating soil profile. After application of urea in paddy field-based two-cropping rice, TN and NHa＋-N concentrations in floodwater reached peak on the 1st and the 3rd day, respectively, and then decreased rapidly over time; all the floodwater NO3--N concentrations were very low; the pH of floodwater gradually rose in case of early rice within 15 d （late rice within 3 d） after application of urea, and EC remained consistent with the dynamics of NH4^＋-N. The applied CRNF, especially 70% CRNF, led to significantly lower floodwater TN and NH4^＋ concentrations, pH, and EC values compared with urea within 15 d after application. The monitoring result for N loss due to natural rainfall runoff indicated that the amount of TN lost in runoff from paddy field- based two-cropping rice with urea application in Dongting Lake area was 7.47 kg ha^-1, which accounted for 2.49% of urea- N applied, and that with CRNF and 70% CRNF application decreased 24.5 and 27.2% compared with urea application, respectively. The two runoff events, which occurred within 20 d after application, contributed significantly to TN loss from paddy field. TN loss due to the two runoffs in urea, CRNF, and 70% CRNF treatments accounted for 72, 70, and 58% of the total TN loss due to runoff over the whole rice growth season, respectively. And the TN loss in these two CRNF treatments due to the first run-off event at the 10th day after application to early rice decreased 44.9 and 44.2% compared with urea, respectively. In conclusion, the 15-d period after application of urea was the critical time during which N loss occurred due to high floodwater N concentrations. But CRNF decreased N concentrations greatly in floodwater and runoff water during this period. As a result, it obviously reduced TN loss in runoff over the whole rice growth season.     

Increase in yield and nitrogen use efficiency of double rice with long-term application of controlled-release urea

Controlled-release urea(CRU) has better characteristics than conventional urea for synchronizing nitrogen(N) release with plant uptake. Understanding the effects of CRU on crop yield and N use efficiency(NUE) has long been the key to evaluate the performance of CRU. A long-term experiment over five consecutive years was conducted in Changsha, Hunan Province, China, to investigate the effects of polyethylene-coated urea with a 90-d release period on the yield and NUE of double rice(early and late...     

The Variation ofβ-glucan and Protein Content in Barley as Affected by Agronomic Practices

The influences of N applicationrate, timing, sowing date and seeding rate on β-glucan and protein content in barley grains were studied through the field experiments in Hangzhou, China during 1997 -2001. Protein content increased with N application rate and with N proportion applied at late stage. β-glucan content also responded significantly to N application rate and timing, but with different pattern with protein content. Of three N rate treatments, the medium N rate (135 kg ha-1) had the highest β-glucan content, being significantly higher than low N rate (90 kg ha-1) and no difference with high N rate (180 kg ha-1). Among three N timing treatments, two times of N top-dressing at both tillering and booting stage had significantly higher β- glucan content than once N top-dressing at tillering or booting stage. Sowing date has the dramatic effect on both β-glucan and protein content. Protein content decreased with the delayed sowing, and kernel weight showed opposite tendency. Either earlier or later sowing caused increased β- glucan content relative to sowing in early November, which is the normal date for barley sowing locally. Seeding rate had no significant influence on both β- glucan and protein content.     

Effects of Ridge-Mulching with Plastic Sheets for Rainwater-Harvesting Cultivation on WUE and Yield of Winter Wheat

A field experiment was conducted in a manural loesial soil in middle of Shaanxi Province of China, a sub-humid area prone to drought, to study the effects of rainwater-harvesting cultivation on water use efficiency (WUE) and yield of winter wheat. Ridge-furrow tillage was used, the ridge being mulched by plastic sheets for rainwater harvesting while seeding in the furrows. Results showed that from sowing to reviving stage of winter wheat, water stored in 0-100cm layer was significantly decreased whereas that in 100-200cm layer did not change. Compared to the non-mulching, plastic mulch retained 6.5mm more water as an average of the two N rate treatments, having a certain effect on conservation of soil moisture. In contrast, at harvest, water was remarkably reduced in both the 0-100cm and the 100-200cm layers, and mulched plots consumed 34.8mm more water as an average of the two treatments: low N rate (75kg N ha^-1) with low plant density (2300000 plants ha^-1) and high N rate (225 kg N ha^-1)with high plant density (2800000 plants ha^-1) , in 0-200cm layer than those without mulching, the former being beneficial to plants in utilization of deep layer water. Mulching was significant in harvesting water and in increase of yield. Mulched with plastic sheets, biological and grain yields were 22.5 and 22.6% higher for the average of the high N rate than for the low N rate,and the high N rate with low plant density was 29.8 and 29.1% higher in both biological and grain yields than that of the low N rate with low plant density. With high N rate and high plant density, the mulched biological and grain yields were 39.5 and 28.9% higher than the corresponding treatments without mulching. Of the treatments, that with high N rate and low plant density was the highest in both biological and grain yields, and the water use efficiency reached 43.7kg mm^-1 ha^-1 for biological yield and 22 kg nn^-1 ha^-1 for grain yield, being the highest WUE reported in the world up to now.     

Non-leguminous winter cover crop and nitrogen rate in relation to double rice grain yield and nitrogen uptake in Dongting Lake Plain,Hunan Province,China

Annual ryegrass(Lolium multiflorum Lam.), a non-leguminous winter cover crop, has been adopted to absorb soil native N to minimize N loss from an intensive double rice cropping system in southern China, but a little is known about its effects on rice grain yield and rice N use efficiency. In this study, effects of ryegrass on double rice yield, N uptake and use efficiency were measured under different fertilizer N rates. A 3-year(2009–2011) field experiment arranged in a split-plot design was undertaken. Main plots were ryegrass(RG) as a winter cover crop and winter fallow(WF) without weed. Subplots were three N treatments for each rice season: 0(N_0), 100(N_(100)) and 200 kg N ha–1(N_(200)). In the 3-year experiment, RG reduced grain yield and plant N uptake for early rice(0.4–1.7 t ha–1 for grain yield and 4.6–20.3 kg ha–1 for N uptake) and double rice(0.6–2.0 t ha–1 for grain yield and 6.3–27.0 kg ha–1 for N uptake) when compared with WF among different N rates. Yield and N uptake decrease due to RG was smaller in N_(100) and N_(200) plots than in N_0 plots. The reduction in early rice grain yield in RG plots was associated with decrease number of panicles. Agronomic N use efficiency and fertilizer N recovery efficiency were higher in RG plots than winter fallow for early rice and double rice among different N rates and experimental years. RG tended to have little effect on grain yield, N uptake, agronomic N use efficiency, and fertilizer N recovery efficiency in the late rice season. These results suggest that ryegrass may reduce grain yield while it improves rice N use efficiency in a double rice cropping system.     

Correlation Analysis of Rice Seed Setting Rate and Weight of 1 000-Grain and Agro-Meteorology over the Middle and Lower Reaches of the Yangtze River, China

The purpose of this study is to reveal the effects of historic climate change on rice yield over the middle and lower reaches of the Yangtze River, China, and to better adapt to climate change in the future. This study presents the relation of temperature and precipitation and rice components from 1981 to 2003 at 48 early rice stations and 30 middle rice stations. It focuses on an analysis of three stages： flowering, pre-milk, and late milk. The results show that mean maximum temperature and mean daily precipitation at the stages of flowering and pre-milk are most related to early rice yield. Yield change of middle rice is mainly because of mean precipitation change at the flowering stage. Furthermore, percentage of undeveloped grain increases as mean maximum temperature rises at the flowering stage. Over-precipitation in the reproductive stage is a major reason for reduction in yield of early rice. Consecutive rainfall and continuous high temperature can have negative effects on middle rice yield. Global warming would affect middle rice more seriously than early rice.     

Yield Effect of Chemical and Soil Nitrogen on the Mid-season and Ratooning Hybrid Rice

Using hybrid rice Yixiang1577 as the material, the mid-season and ratooning hybrid rice yield variation was studied in Southem Sichuan at different levels of nitrogen fertilizer. The results showed that rice yield by using N fertilizer increased to the most significant level than no fertilizer ones, and the mid-season rice and rice yield by using more N fertilizer increased to the significant level than less fertilizer ones. The rice yield by using no fertilizer ones increased to the most significant level than some used fertilizer, and the ratooning rice and rice yield by using more N fertilizer decreased to the most significant level than less fertilizer ones. The rice yield by using some fertilizer increased to the most significant level than no fertilizer ones for mid-season＋rationing rice and rice yield by using some fertilizer had no obvious differences at different nitrogen levels. Therefore, application of fertilizer can improve yield of mid-season rice and mid-season＋rationing rice. Soil test results showed that nutrient contents in rice field in South Sichuan were very rich in nitrogen, which could provide more adequate crop growth potential soil nitrogen nutrition. The crops with a deep root system had stronger ability of utilization on soil nitrogen. Therefore, the ratooning rice used no or little N fertilizer had a high yield performance because they made full use of soil nitrogen with deep root system.     

Soil Phosphorus Release to the Water Bodies in the Upland Fields of Yellow Soil Areas and Impacting Factor

Soil phosphorus release to the water bodies in the upland fields of yellow soil areas and impacting factor was studied in Guizhou province. The results showed that the content of dissolved active P of surface runoff from various upland fields of yellow-soil were significantly different, which the concentrations of dissolved active P of runoff correlated with the contents of available-P, amorphous oxides of A1, and organic matter in the soils. The amount of soil phosphorus release to the water bodies affected by the level of applying P fertilizer and the process of corn growth, which with fertilizing from 150 to 900 kg P205 ha^-1 in the soil with high P level, the average contents of dissolved active P in the permeability-water of the soil increased from 0.020 mg L^-1 to 0.137 mg L^-1. The amount of soil phosphorus release to the water bodies also affected by environmental factor, which the amount of soil phosphorus release significantly increased under the conditions that temperature is 30℃-35℃, water/soil ratios is 15：1-25：1, submergence-time by water is 12-18 h and pH value of acid rains is 3.82-3.73.     

Nitrate leaching of winter wheat grown in lysimeters as affected by fertilizers and irrigation on the North China Plain

Proper application of nitrogen(N) fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency(NUE). A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons(response variables were nitrate transport, N leaching, and NUE). Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha-1 rate in 2011–2012(season 3). In terms of grain yield(GY), dry matter(DM) or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010(season 1), yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake(NU) were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.     

双季杂交稻高产施肥技术研究

采用田间试验研究施肥水平与杂交水稻产量的关系,以及不同生育阶段养分吸收量,据此,提出了夺取杂交水稻高产的施肥技术。 杂交早稻亩产540公斤,需吸收氮10.9公斤、五氧化二磷4.9公斤、氧化钾15.9公斤、二氧化硅43.8公斤;杂交晚稻亩产560公斤,需吸收氮15.9公斤、五氧化二磷5公斤、氧化钾19公斤、二氧化硅63.8公斤.同一施肥水平,杂交晚稻比杂交早稻多吸收氮20％～27.5％,钾7％～24.1％,磷相似。杂交晚稻秧苗期、分蘖盛期吸钾量高于杂交早稻,齐穗后低于杂交早稻;杂交稻要获高产在氮磷水平中上稻田,施钾是第一位因素,杂交早稻应重视中后期施钾,杂交晚稻应重视苗期及早施钾肥;早晚杂交稻要获超500公斤产量其氮磷钾最佳拖肥量分别为12、4、10.7公斤/亩和12、4、12公斤/亩。     

早籼新品种浙408氮肥运筹技术研究

[目的]为浙408的推广应用提供科学依据。[方法]在金华红壤稻区进行浙408全程不同纯氮施用水平及基肥、分蘖肥、穗肥不同比例的氮肥运筹试验,明确浙408对氮肥的需求量。[结果]随着施氮量的增加,浙408的始蘖期、抽穗期和成熟期推迟,生育期延长,单位面积有效穗数、每穗粒数、千粒重和产量先上升后下降。在全程施氮总量相同的情况下,前期施氮量较大处理的始蘖期早,有效分蘖期短。基肥、蘖肥、穗肥按6∶3∶1施用时,浙408的单位面积最高苗数、有效穗数和产量最高,按4∶4∶2和5∶3∶2施用时,每穗实粒数、结实率和千粒重较高。[结论]浙408全程纯氮总量为172.5~210.0 kg/hm2,基肥、分蘖肥、穗肥按5∶3∶2或6∶3∶1施用可获得较高产量。     

氮用量运筹对免耕早稻产量构成的研究

[目的]探索氮肥在免耕早稻水稻的合理应用。[方法]以皖稻143为供试品种,小区试验,塑盘旱育,氮肥施用量设5个处理(0、135、180、225、270 kg/hm2),研究了施氮对免耕早稻产量构成的影响。[结果]各处理的早稻群体茎蘖动态随氮素用量增加而增加,生育期随着施氮量的增加而延长。早稻产量随施氮量的增加而提高,施氮处理产量比对照增产3 601.80～4 869.15 kg/hm2,提高131.71%～177.29%。产量和效益均能获得较好的施氮用量处理是180 kg/hm2,其中基施90 kg/hm2,促蘖肥施45 kg/hm2,保花肥45 kg/hm2。早稻增施氮肥可延长生育期,每增施3 kg氮素可延长1 d生育期。[结论]氮用量运筹对免耕早稻茎蘖动态、产量及构成因素有一定的影响。     

双季稻种植下不同类型土壤连续施用控释氮肥的效应研究(英文)

[目的]研究水稻控释氮肥在洞庭湖区双季水稻种植体系下的连续施用效应。[方法]在洞庭湖区3种主要类型土壤上进行连续4年的微区试验,试验设不施肥(CK)、尿素、等氮量控释氮肥及70%氮量控释氮肥4个处理。[结果]等氮量控释氮肥的处理所获得的水稻产量最高,在河沙泥、紫潮泥和红黄泥上比尿素处理分别增产10.3%、8.0%和2.4%;70%N量控释氮肥处理分别增产6.1%、2.6%和-0.8%;在3种土壤上早、晚稻及全年平均吸N量均表现为等N量控释氮肥>70%N量控释氮肥>尿素>对照。等N量控释氮肥处理在上述3种土壤上的肥料利用率分别为60.7%、59.6%和56.3%,比尿素处理分别高23.8%、19.4%和16.3%,早稻随施用年份的延长其利用率呈增加趋势,且高于70%N量控释氮肥处理,晚稻连续施用3年时利用率由上升转为下降趋势。[结论]连续施用控释氮肥可缓解土壤氮素肥力和有机碳含量的下降,特别是在河沙泥稻田中。施用控释氮肥有利于水稻增产、氮肥利用率的提高及土壤培肥。     

Measurement of Ammonia Emission Following Surface Application of Urea Fertilizer from Irrigated Paddy Rice Fields

Ammonia emission is one of the most important pathways of nitrogen loss from agricultural cultivated field. In this paper, we report the measurement of ammonia emission from paddy rice field obtained by surface application of urea fertilizer with water management. The main objective of the present study were to assess the amount of NH3 emission and the loss of nitrogen from paddy field as affected by various N doses, i.e., 0 (control), 90 (N1), 180 (N2), 270 (N3) and 360 (N4) kg ha-1, following field surface application of urea fertilizer with water management. Ammonia emissions were measured by continuous airflow enclosure method from plots fertilized with the application of surface urea. Increase in urea-N dosage increased NH3 emission thatwas measured from paddy rice field. Ammonia emission started immediately and was almost complete within 12 days after top dressing of urea application to the soils. Ammonia emissions were nearly constant in all treatments from 12 days after fertilizer application. Highest ammonia emission rate was 28 g/day and total amount of ammonia emission was 56.21 kg ha-1 for 360 kg N ha-1 dose. No remarkable observation was found about temperature for ammonia emission. Due to proper water management practices less emission was observed throughout the experiment period. The results also show that N loss through NH3 emission accounted for 11 to 16% during the ricegrowing season. These magnitudes of loss of N appear to be most important for environmental point of view.     

两系杂交中籼华安3号高产栽培技术

华安３ 号最适宜的秧龄、密度、纯氮分别是３８ｄ、２２．５ 或１５．０ 万穴／ｈｍ ２、１８７．５ｋｇ／ｈｍ ２。必须施足基面肥,不施促蘖肥,以促苗早发、快发,奠定大穗基础;超前搁田,在每公顷茎蘖苗达１５０ 万时即开始搁田,以稳苗健株,协调群体发展,控制无效分蘖,增加有效积累;合理巧施穗粒肥,养根保叶,活熟到老,提高结实率和千粒重,夺取高产。     

丰华占和粤香占对水肥互作的产量效应

通过大田试验研究了常规水作(P)和覆草旱作(M)、肥料种类、肥料用量(高量,HD;低量,LD)及其 交互作用对丰华占和粤香占水稻籽粒产量的影响。结果表明,肥料种类对早稻、晚稻产量均无明显影响,基肥1次 施用芭田包膜控释肥(BT)和华南农大控释肥料(AgroBB)的产量与分3次施用尿素(Urea)的相同。早稻尿素处 理,M的产量>P的产量,两种控释肥均表现为P的产量>M的产量;晚稻均是P的产量>M的产量。晚稻覆草旱 作Urea,BT,AgroBB处理较常规水作的相应肥料处理分别减产17．6％,21．5％和12．1％。早、晚稻水作BT和 AgroBB的效果优于旱作,旱作下晚稻的效果优于早稻,两种控释肥料间AgroBB的效果优于BT。施N量150 kg／hm2的产量显著大于225 kg／hm2。早稻LD的产量较HD高4．6％-7．2％,晚稻的高7．1％-9．7％。早晚稻 尿素处理LD的增产率最大,BT和AgroBB的无显著差异。早稻、晚稻各种肥料处理下,丰华占和粤香占的产量均 无明显差异。除AgroBB处理早稻的水分管理X施肥量X品种,及晚稻的水分管理X施肥量、施肥量X品种的交互 作用对水稻产量有显著影响外,其余的肥料,施肥量、水分管理、品种间的交互作用对水稻产量无显著影响。试验中 施用尿素和BT的稳产性差,而AgroBB具有稳产效果。在珠江三角洲栽培丰华占,建议早稻采用浅灌和利用降雨, 结合稻草覆盖的水分管理措施,每公顷施用150 kg N(尿素),并按基肥40％,分蘖初期30％和分蘖末期30％分 配。晚稻可采用同样的施肥量和分配原则,但建议在孕穗期和抽穗期采用常规水作以获得最大产量。     

化肥减量条件下不同施用方法对土壤养分有效性及水稻产量的影响

大田试验条件下,采用裂区试验研究了翻压紫云英后化肥减量施用条件下不同施肥方法对土壤养分有效性及水稻产量的影响。结果表明:翻压紫云英22500kg/hm2后,配施80%化肥,底肥:分蘖肥:穗肥=5:5:0,与习惯施肥方法相比,早稻和晚稻收获后土壤中有效氮分别平均增加5.6%和9.8%;而底肥:分蘖肥:穗肥=3:4:3更有利于提高有效K含量,分别平均增加8.9%和13.2%;配施60%化肥,按底肥:分蘖肥:穗肥=5:5:0施肥显著增加早稻收获后土壤中有效K含量,增幅为27.1%;肥料全部用作分蘖肥时降低晚稻或早稻收获后土壤有效N、K含量;配施60%～80%化肥,早稻和晚稻产量均以施肥方法底肥:分蘖肥:穗肥=0:7:3最佳。     

Effects of Long-Term Application of Sulfur-Containing and Chloride-Containing Chemical Fertilizers on Rice Yield and Its Components

Impacts of 33-yr of application of S-containing and Cl-containing chemical fertilizers on rice (Oryza sativa L.) yield and its components were investigated in a red paddy field experiment, south China. The treatments included: 1) adding 302 kg SO42-S ha-1 yr-1 with application of (NH4)2SO4, K2SO4, and calcium superphosphate (SO42-); 2) adding 56 kg SO42--S and 176kg CI ha-1 yr-1 with application of urea, calcium superphosphate, and KC1 (C1-+SO42-); 3) adding 516 kg C1 ha-1 yr-1 with application of NH4C1, KC1, and KH2PO4 (Cl-). Under each treatment, the applied N, P, and K nutrients were controlled at conventional rates of 150 kg N ha1- yr-1, 75 kg P2O5 ha-1 yr-1, 225 kg K2O ha-1 yr-1, respectively. Under the S-containing fertilizer application, soil SO42--S content showed a first increasing then decreasing trend with years, and was significantly negatively correlated with annual rice yield. Average annual yield significantly declined in an order of Cl-, C1-+SO42-, and SO42-. Under the Cl- treatment, soil SO42--S content was maintained at about 26.5 mg kg-1, not showing deficiency. From 1990 to 2000, rice yield declined rapidly under the SO42- treatment, and was significantly lower than that under the C1-treatment. After then, there was no significant difference in yield among the treatments. Our results demonstrated that long-term application of S-containing fertilizer could result in excessive accumulation of SO42--S in the red paddy soils of south China, therefore producing a certain threat to rice growth. The Cl-containing fertilizer could be relatively safe.