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1.
ABSTRACT

The study was aimed to determine the appropriate nitrogen (N) rate to combine with liming for enhanced maize yield and nitrogen use efficiency (NUE). Two maize varieties [Ikom White (IKW) and Obatanpa-98 (Oba-98)], two lime rates (0 kg ha?1 and 500 kg ha?1) and three N rates (0, 90 and 180 kg ha?1) were used. The treatments were laid as a split-split plot in a randomized complete block design with three replications. The growth attributes, photosynthetically active radiation (PAR), harvest index, dry matter, and grain yield increased (P ≤ 0.05) with increases in N rates, especially in plots amended with lime. Oba-98 was better yielding (2.12 versus (vs) 1.88 t ha?1) and absorbed more (P ≤ 0.05) radiation (442.06 vs 409.54 μmol m?2s?1) than IKW. The efficiency indices and partial factor productivity were best optimized at the 90 kg ha?1 N rate with Oba-98 having higher values than IKW. Therefore, liming (500 kg ha?1) plus N at 180 kg ha?1produced the best yield of the hybrid maize, Oba-98.  相似文献   

2.
ABSTRACT

Our aim was to determine the combined effect of brassinolide (BR) and lime on the growth and yield of maize on acid soils of South East Nigeria using two BR levels (0 and 250 mL), two maize varieties [Ikom White (IKW) and Oba-98] and two lime levels (0 kg ha?1 and 500 kg ha?1). The IKW was better (P ≤ 0.05) in growth morphology than Oba-98; however, Oba-98 was more (p ≤ 0.05) efficient in intercepting radiation (420.16 μmol m?2s?1) than IKW (325.08 μmol m?2s?1). The 500 kg ha?1 lime plus BR improved (P ≤ 0.05) nitrogen (N) uptake, dry matter yield, harvest index, shoot to root ratio, and grain yield, especially in Oba-98. Thus, the interactive action of BR and lime could increase the soil pH to an extent for enhanced yield of hybrid maize.  相似文献   

3.
Evaluation of any crop response to different nitrogen amounts is important for determining the amount that can be considered as optimum from economical and environmental point of view. This study was conducted to (1) evaluate the growth and yield of pumpkin (Cucurbita pepo L.) under different nitrogen rates and (2) determine the nitrogen use efficiency (NUE) of pumpkin in two growing seasons (2013 and 2014). In both growing seasons, nitrogen fertilizer (at three rates including 50, 150, and 250 kg ha?1) was band-dressed on the planted side of each furrow, coinciding with 4–6 leaves stage and flowering. Crop performance over 2 years was evaluated by measuring shoot dry matter, crop growth rate (CGR), leaf area index (LAI), leaf area duration (LAD), intercepted PAR (PARi), radiation use efficiency (RUE), shoot nitrogen uptake, water use efficiency (WUE), NUE, and fruit and seed yield. The results showed that in both growing seasons, the highest growth and yield of pumpkin were obtained by applying 250 kg N ha?1 (using urea fertilizer containing 46% nitrogen). Increased nitrogen rate from 50 to 250 kg ha?1 resulted in 87.3%, 27.0%, 62.1%, 87.5%, and 84.5% increase in shoot dry weight, RUE, WUE, fruit yield, and seed yield of pumpkin, respectively, across both growing seasons. However, higher application nitrogen rate decreased the NUE of pumpkin, i.e., the NUE decreased by 62.5% when the nitrogen rate increased from 50 to 250 kg ha?1. The effect of nitrogen applied in 2014 growing season on growth and yield of pumpkin was higher than that in 2013 growing season, which might be due to more suitable weather condition. In conclusion, the nitrogen rate of 250 kg ha?1 produced the highest amount of fruit and seed yield in pumpkin.  相似文献   

4.
施氮与灌水对夏玉米产量和水氮利用的影响   总被引：10，自引：3，他引：7  
通过田间裂区试验,研究了不同灌水量（900、 1200和1500 m3/hm2）和施氮量（0、 150、 210和270 kg/hm2）对夏玉米生长状况、 产量构成及水、 氮利用效率等的影响。结果表明: 当灌水量超过最低量 900 m3/hm2、 施氮量超过150 kg/hm2时,二者对玉米产量、 产量构成因素（穗粒数、 百粒重及穗粒重）和收获指数（HI）以及各生育期干物质积累量等均没有明显影响; 氮肥农学效率和氮肥偏生产力随氮肥用量的增加呈明显降低趋势; 灌水生产效率和水分利用效率随灌水量的增加也显著降低,二者均表现为900 m3/hm21200 m3/hm21500 m3/hm2。因此,在本试验条件下,以W900N150处理的水、 氮利用效率、 产量及其构成因素等较高,并且对环境造成潜在危害最小,为当地地域气候条件下夏玉米生产中节水减氮的较为适宜的水氮配比。  相似文献   

5.
ABSTRACT

The present investigation aimed to determine the effectiveness of different nitrogen (N) rates on grain yield, growth, and water use efficiencies of direct wet-seeded rice and to create a relationship of N rates with growth parameters and dry matter production at different stages. The experiments compared six rates of nitrogen (0, 40,80,120,160, and 200 kg ha–1N) replicated thrice in randomized complete block design in two conjunctive years of 2009–2010 and 2010–2011 at Bangladesh Rice Research Institute farm, Gazipur.The highest grain yield of 7.85 and 7.22 t ha?1 was observed in N200 treatment in 2009–2010 and 2010–2011, respectively. The relationship (R2) of total dry matter with leaf area index , leaf area duration, and crop growth rate indicated strong association during booting stage to achieved maximum dry matter during harvest. Water use efficiency varied 87–91% in different N levels.  相似文献   

6.
Yield, dry matter production, nitrogen (N) uptake and nitrogen use efficiency (NUE) of Bangladesh Rice Research Institute (BRRI) dhan29 were investigated during two consecutive dry (Boro) seasons of 2009–10 and 2010–11. The experiments were set up in a randomized complete block design with three replication having six nitrogen (N) levels of 0, 40, 80 120, 160 and 200 kg ha?1. Nitrogen fertilization increased yield characters, dry matter production and N uptake. The economic optimum rate of N was 166 and 155 kg ha–1 in first and second year, respectively, with corresponding yield of 7.1 and 6.5 t ha?1. NUEs were higher in the first year, decreased with increasing N rates in most cases. Gross return over fertilizer reached the highest Tk 692 in 2009–10 and Tk 489 in 2010–11 with 160 kg N ha–1. The results suggest that BRRI dhan29 should receive an average of 160 kg N ha?1 for economic optimum yield.  相似文献   

7.
Field experiments on cotton with different forms of urea applied at rates of 40 and 80 kg N/ha were carried out. The results indicated that application of nitrogen increased plant height, dry matter accumulation, number of bolls per plant, seed cotton yield and nitrogen uptake. The proportion of dry matter and nitrogen in the stem was increased and that in the leaves was reduced by N application. Sulphur coated urea (all applied at sowing) was about the same in effect as N-Serve treated urea and gave significantly more seed cotton yield than untreated urea, neem cake treated urea and sulphur coated urea (applied in two splits). Nitrogen efficiency as expressed by kg seed cotton production per kg N applied was greater with 40 kg N/ha rate than with 80 kg N/ha. Sulphur coated urea (all applied at sowing) gave the highest nitrogen efficiency followed by N-Serve treated urea.  相似文献   

8.
20062~008年在四川省广汉市开展了保护性耕作措施下水稻氮肥调控试验,设置不同秸秆还田量(0、6000、12000 kg/hm2)、施氮量水平(0、1502、10 kg/hm2)以及氮素分配比例(6∶2∶2、6∶3∶1、8∶2)。结果表明,和施N 150 kg/hm2相比,N 210 kg/hm2处理水稻分蘖力、干物质积累量、开花期的植株个体和群体质量均有升高,花后茎鞘贮藏物质的输出及光合物质积累量增加,子粒产量提高7.3%。在施N 150 kg/hm2水平和基肥∶蘖肥∶穗肥=6∶2∶2分配比例下,与旋耕无麦秸还田处理相比,免耕秸秆还田与否对水稻茎蘖消长、干物质积累及子粒产量影响较小,但花后绿叶功能期延长,光合产物积累在产量形成中所占比例增加。在施N 210 kg/hm2水平和基肥∶蘖肥∶穗肥=6∶3∶1分配比例下,免耕还田麦秸量从6000 kg/hm2增加至12000 kg/hm2,水稻分蘖力明显增强,干物质积累量增大,开花期个体和群体质量提高,单位面积穗数和穗实粒数增多,产量增加4.1%;将氮肥分配比例由6∶3∶1变为8∶2,即增加基肥用量,减少中后期的氮素供应会导致分蘖高峰后分蘖大量死亡,有效穗数降低,穗粒数减少,产量下降。以上结果说明,氮素的充分供应是保护性耕作水稻获得高产的重要前提和基础,适当提高麦秸还田量、增加中后期氮素供应,能提高氮素利用率及分蘖成穗率和结实率,利于稳产高产。  相似文献   

9.
Strawberry plants are relatively unresponsive to nitrogen (N) fertilization. Supraoptimal N application also results in excessive vegetative growth, which competes to reproductive growth. Two strawberry field experiments were conducted for two consecutive years using fertigation to investigate the effect of different nitrogen (N) application rates on yield and growth of an everbearing strawberry (cv. Evie II). N was injected weekly into the drip irrigation system at 0, 0.5, 1, 3, and 6 kg N/ha/week the first year and 0, 1, 2, and 3 kg N/ha/week the next year. Fruit yield and fruit number were not affected the first year, but were increased the second year due to N application. However, there was no effect of N nutrition on average berry weight for both years. It was concluded that N fertilization may increase yield and fruit number, but average berry weight remains unaffected.  相似文献   

10.
A field investigation was conducted at the Indian Agricultural Research Institute's Research Farm during the kharif (wet) seasons of 2002 and 2003 in a split plot design with three replications, consisting of 27 treatments, namely, main plots: three varieties (PRH-10, Pusa Sugandh-3 and Pusa Basmati-1) and three plant spacings (20 × 10, 20 × 15 and 20 × 20 cm2) and sub-plots: three levels of nitrogen (0, 80 and 160 kg N ha?1). The research results indicated that aromatic rice hybrid PRH-10 produced 33 and 6%, respectively, more grain yield than that of Pusa Sugandh-3 and Pusa Basmati-1. The appreciable higher grain yield of PRH-10 over Pusa Sugandh-3 and Pusa Basmati-1 was due to considerable improvement in most of the yield attributing characters. Application of 160 kg N ha?1 recorded 23.7 and 26.1% more grain yield over no nitrogen application whereas it was 6.4 and 6.1% more over 80 kg N ha?1, respectively, during first and second year of the experimentation. Wider plant spacing of 20 × 20 cm2 and application of 160 kg N/ha recorded significantly higher hulling, milling and head rice recovery compared to closer spacing and zero nitrogen application.  相似文献   

11.
施氮量和种植密度对高产夏玉米产量和氮素利用效率的影响   总被引：26，自引：5，他引：21  
选用DH661和ZD958为试验材料,设置0、120、240、360 kg/hm2 4个施氮水平和60000、75000、90000株/hm2 3个种植密度,研究了施氮量和种植密度对高产夏玉米产量和氮素利用效率的影响。结果表明,与低密度60000 株/hm2相比,增施氮肥可显著增加90000株/hm2高密度下玉米的单株干物质积累量、群体干物质积累量、籽粒产量、总氮素积累量、氮素转运量。90000万株/hm2种植密度条件下,随施氮量增加,氮素转运效率及贡献率呈上升趋势,而氮肥偏生产力、氮肥农学效率、氮肥利用率呈下降趋势。本试验条件下,适量增施氮肥可以显著提高高种植密度下玉米的籽粒产量和氮素利用效率。综合考虑产量和氮素利用效率两因素,ZD958和DH661两品种获得高产适宜的种植密度为90000株/hm2,施氮量为240360 kg/hm2。  相似文献   

12.
秸秆覆盖与氮肥运筹对杂交稻根系生长及氮素利用的影响   总被引：18，自引：2，他引：18  
【目的】在我国稻-麦、稻-油等多熟制区域,富含氮素的小麦、油菜等水稻前茬作物秸秆被大量弃置、焚烧,造成极大浪费和环境污染,与此同时,稻季氮肥投入量却在逐年增加,因此在水稻生产中研究秸秆覆盖与氮肥配合施用的理论与技术,对实现秸秆还田与减少氮肥用量具有重要意义。本试验研究油菜、小麦2种秸秆覆盖方式下,3种不同的氮肥运筹方式对杂交稻主要生育时期根系生长、氮素吸收利用特征及产量的影响,并探讨其根系生长与氮素利用及产量间的关系,以期寻求最佳的秸秆还田与氮肥运筹搭配模式。【方法】本试验以杂交稻F优498为材料,采用两因素裂区试验设计,主区为小麦秸秆覆盖(S1)、油菜秸秆覆盖(S2)和无秸秆覆盖(S0);副区为氮肥运筹模式,在135 kg/hm2总施氮量条件下,设置基肥∶蘖肥∶穗肥为5∶3∶2(N1);基肥∶蘖肥∶穗肥为3∶3∶4(N2);基肥∶蘖肥∶穗肥为3∶1∶6(N3)3种氮肥运筹模式,以不施氮肥(N0)为对照。研究各处理杂交稻在移栽后20 d、移栽后30 d、齐穗期和成熟期根系生长及形态、各生育期的干物质与氮素积累,水稻茎鞘的干物质转运、产量及其构成因子以及各时期氮素积累及利用效率,同时对各生育时期根系生长与氮素利用及产量间的关系进行分析。【结果】结果表明,小麦秸秆覆盖均可有效促进杂交稻各生育时期的根系生长、改善根系形态、增加各时期的干物质与氮素积累,提高氮肥的利用效率及稻米产量。在不同种类秸秆覆盖下,基肥∶蘖肥∶穗肥(倒4叶龄期施入)为3∶3∶4(N2)时,可及时地对杂交水稻主要生育时期的根系生长进行调控,有效促进抽穗至成熟期的干物质积累与转运率,提高水稻主要生育时期的氮素积累及氮肥利用效率,显著增加稻谷产量,为本试验中最优的氮肥管理模式;而氮肥后移比例过高(基肥∶分蘖肥∶穗肥运筹比例为3∶1∶6),会限制齐穗期根系的生长,导致稻谷产量及氮肥利用效率降低。相关性分析表明,秸秆覆盖与氮肥运筹下主要生育时期根干重、根体积、总根长与产量及氮素吸收利用均存在显著或极显著的正相关(r=0.38*0.78**),尤其以齐穗期的根体积与总根长、根干重与氮素累积、产量及氮素回收利用率的相关性最好。【结论】小麦秸秆、油菜秸秆覆盖能够有效促进杂交稻根系的生长,增加干物质与氮素积累,提高氮肥利用效率,且小麦秸秆覆盖效果更显著。秸秆覆盖条件下,氮肥运筹以基肥∶蘖肥∶穗肥为3∶3∶4时的水稻根系生长旺盛,物质生产能力强,氮肥利用效率最高。因此,小麦秸秆覆盖与基肥∶蘖肥∶穗肥以3∶3∶4的比例配合的水稻的产量最高,为最优组合。  相似文献   

13.
Abstract

Sulfur (S) deficiency has been reported in some upland soils of the southern United States and S application has improved forage quality on the low‐S soils. A field experiment was conducted for three years to determine ryegrass (Lolium multiflorum L.) dry matter yield and forage quality response to S fertilization. Prilled elemental S was applied each year at two rates (0 and 45 kg S/ha) in combinations with three rates of nitrogen (N) (168, 224, and 280 kg/ha). Wet depositions of S in rain were monitored over the seasons. Sulfur fertilization generally did not increase seasonal dry matter yield and plant uptake of S. Nitrogen application generally increased dry matter yield and protein content during the season. Averaged over the three‐year period, however, forage yield and S uptake increased from 7.7 to 10.5 Mg/ha and 13.9 to 18.8 kg/ha, respectively, as N fertilization increased from the lowest to highest treatment rates. Forage dry matter for each harvest ranged from 0.6 to 2.2 Mg/ha, while S, protein, in vitro dry matter digestibility (TVDMD), and N/S ratio tended to decline seasonally from 2.5 to 1.8, 266 to 142, and 795 to 716 g/kg, and 17.8 to 11.9, respectively. Sulfur input from rainfall was small with a three‐year average of 5.8 kg/ha (±0.64 SE). In some locations of the southern United States, S may not be limiting even when applying high rates of N to high‐yielding forages which annually remove large quantities of S. Because of the lack of yield response from S application and low inputs of S from wet deposition, S from sources other than rainfall may have been considerable.  相似文献   

14.
Greenhouse experiments were conducted to determine the effects of nitrogen (N), phosphorus (P), and potassium (K) fertilizer on biomass yield and flavonoid content of American skullcap (Scutellaria lateriflora). Each experiment was carried out two times and consisted of six levels of each nutrient. The regressions gave maxima for dry matter, baicalein yield, and chrysin yield at 446, 412, and 351 kg N/ha for N fertilizer, respectively. Dry matter yield exhibited linear response to P application. The yield of scutellarein, baicalin, baicalein, and chrysin increased with addition of P. The regression gave maximum for dry matter at 208 kg K/ha for K fertilizer. A linear response to K fertilization was observed for scutellarein concentration. P application had the greatest effect on the flavonoids analyzed, whereas K had least, which may be attributed in part to the presence of K in the fritted clay medium.  相似文献   

15.
In Northern Spain, winter wheat is usually fertilized with 180–220 kg N/ha split in two applications. To reduce this rate, a strategy was tested which comprised three nitrogen (N)-applications, the latter being tuned to the nutritional needs of the crop using a chlorophyll meter. N-fertilization experiments were performed on winter wheat (Soissons variety). Treatments consisted of three N-broadcasts of 40, 60, and either 0, 40, 60, or 80 kg N/ha respectively applied at Zadoks scale growth stages 21, 30, and 37. An over-fertilized treatment of 220 kg N/ha was included for normalization of chlorophyll-meter values. Chlorophyll-meter readings were performed at growth stage 37, before fertilization. When normalized chlorophyll-meter values were below 92%, yield and grain protein contents attained with 40+60+0 kg N/ha could be respectively enhanced with third applications of 60 or 80 kg N/ha and 40 kg N/ha.  相似文献   

16.
氮硫配施对生姜生长和氮素吸收的影响   总被引：5，自引：1，他引：5  
【目的】施肥显著影响生姜的产量及品质,在施氮的基础上合理增施硫肥可通过协调氮代谢的能力,促进干物质的合成与积累,从而提高生姜产量。本文在砂姜黑土区采用田间试验,研究氮硫配施对生姜不同生育期干物质积累、产量及氮素吸收的影响,为提高生姜产量及养分吸收提供理论依据。【方法】试验设置4个N水平(0、300、450、600 kg/hm2)和2个S水平(S 0、50 kg/hm2),在发棵期、根茎膨大期和收获期取样,测定茎、叶及根茎的干物质量及含氮量。【结果】生姜的茎和叶生长主要集中在前期,根茎膨大期时的茎和叶干物质量分别为5.49.3 g/plant和7.0 11.6 g/plant;根茎则在后期快速积累,至收获期时根茎干物质量达20.0 36.8 g/plant。随施氮量的增加,不同生育期茎和叶的干物质量均随之增加。适宜施氮量内,生姜根茎干物质量和产量表现出随施氮量增加而增加的趋势,以N450S50处理最高。相较于N0S0处理和N0S50处理,不同施氮量处理生姜增产率分别在33.1%74.3%和25.4%64.2%之间。同一施氮量下,增施硫肥处理的生姜干物质量和产量较高。氮硫配施对生姜根茎、茎和叶氮含量有不同影响。各器官中叶的氮含量在不同生育时期均高于根茎和茎,其中以根茎膨大期较高,为24.3 28.4 g/kg;而根茎和茎的氮含量均在发棵期较高,分别为18.3 24.5和16.3 22.2 g/kg。不同处理中,根茎氮含量在N600S50处理中较高,而茎和叶氮含量则是在N450S50处理中最高。收获期生姜各器官氮累积量表现为根茎叶茎,其中N450S50处理的根茎氮累积量高于其他处理,而茎和叶中则是N600S50处理的氮累积量最高。整株氮累积量随施氮量的增加而增加,N450S50处理最高,较N0S0处理和N0S50处理分别上升116.2%和99.0%,过量施氮反而降低氮素累积。增施硫肥能提高氮累积量,增加幅度在8.1%15.8%之间。【结论】生姜根茎干物质量主要在根茎膨大期积累,实际生产中在这一时期追施氮、钾肥,对于提高生姜根茎生物量,获得高产具有重要作用。氮和硫存在很强的内在联系,适宜施氮量下增施硫肥能够促进同化产物的形成,使养分向生长旺盛部位转移,从而提高生姜干物质积累和产量,促进植株对氮素的吸收。过量施氮或氮硫比例不合理则会导致产量提升受限。  相似文献   

17.
不同氮营养水平对茶叶产量和品质的影响   总被引：13，自引：2，他引：11  
采用田间试验,研究了年施纯N 90 kg/hm2、180 kg/hm2、360 kg/hm2、720 kg/hm2 4种不同氮素营养水平对茶叶干物质产量和品质的影响。结果表明,氮肥对茶叶的干物质产量和品质有明显的影响,合理的施氮量能显著提高茶叶产量并改善其品质。所有处理中,年施纯N 360 kg/hm2获得了最高干物质产量,超过这一施肥量,产量便开始下降。在同一基础肥力土壤条件下,茶叶干物质产量表现为随施氮量的加大先增加后降低,呈抛物线趋势。品质结果分析显示施用适量氮肥能明显提高茶叶中的游离氨基酸、咖啡碱和水浸出物含量,而茶多酚含量降低; 茶树叶片中的叶绿素含量也呈升高趋势。在4种施肥水平条件下,茶叶增产幅度为19.59%、25.19%,平均22.39%; 茶叶品质成分,特别是游离氨基酸含量有明显提高。  相似文献   

18.
施氮量对枣棉间作棉花干物质积累，产量与品质的影响   总被引：4，自引：1，他引：3  
研究了枣棉间作下棉花干物质积累与产量品质对不同施氮量的响应机制,确定枣棉间作的合理施氮量,为果棉间套作立体种植模式的合理氮肥运筹,提高棉花产量与品质提供理论依据。以在南疆的主栽棉花品种中棉所49为材料,研究了4个氮素水平（N 0、 150、 450 和750 kg/hm2）下棉花干物质的积累和产量的差异。结果表明,不同施氮量下棉花干物质累积存在显著差异,氮素缺乏或过量均影响其干物质在不同生育时期的累积量,使产量降低。施氮量对棉花品质也有显著影响,合理的氮肥用量不但能提高棉花单株结铃数和单铃重,从而提高产量,而且可使其有较好的整齐度,棉纤维长度,比强度和马克隆值。因此,在枣棉间作条件下,施氮量为N 450 kg/hm2 时棉花的干物质积累量较高,增产效果显著,品质较好。  相似文献   

19.
The effect of shade and fertilizer application on nutrient uptake and dry matter (DM) partitioning in cocoyam was evaluated by growing the plant under different levels of shade and fertilizer application at Forest and Horticultural Crops Research Centre, Kade, within a period of 9 months. The shade levels used were 80%, 70%, and 50% shade, and full sunlight exposure. The fertilizer rates used were 112 kg/ha nitrogen, phosphorus and potassium (NPK) (15-15-15 120 kg/ha NPK (15-15-15) in a form) of mineral fertilizer, 112 kg/ha NPK organic fertilizer and no fertilizer (control). The split-plot design was used with shade levels as the main plot factor and fertilizer levels as the sub plot factor. The interaction effect of shade and fertilizer had a significant effect (p ≤ 0.05) on DM of cocoyam leaves, petioles, corm, and cormels as well as nutrient accumulation in plant parts. Cocoyam leaves of plants grown under 50–70% shade stored significantly higher (p ≤ 0.05) quantities of nutrients (1.51 ppm of N, 6.61 ppm of P, and 53.10 ppm of K) and accumulated more DM (71.30 g) than leaves of plants grown under full sunlight exposure which accumulated 1.37 ppm of N, 4.31 ppm of P, 26.06 ppm of K, and 30.7 g DM, at the two rates of the chemical fertilizer application. Under full sunlight exposure, significantly higher amounts of DM were accumulated in the corms and cormels at mineral fertilizer level of 112 kg/ha. At mineral fertilizer rate of 120 kg/ha, nutrient accumulation was significantly higher (p ≤ 0.05) in the corm and cormels (1.72 ppm of N and 7.72 ppm of P) of plants grown under full sunlight exposure than those grown under 70% shade level (0.6 ppm of N and 2.94 ppm of P). Nitrogen and phosphorus accumulation was significant in the petioles of plants grown under the 70% shade level at fertilizer rate of 120 kg/ha. It is recommended that cocoyam be grown under 50–70% shade at a fertilizer rate of 112–120 kg/ha for leaf production and under full sunlight exposure at 112 kg/ha (NPK) for cormel production.  相似文献   

20.
东北黑土区大豆生长、结瘤及产量对氮、磷的响应   总被引：6，自引：0，他引：6  
氮肥和磷肥显著影响大豆的结瘤和产量。然而在土壤肥力较高、速效养分有效性差的东北地区,有关氮肥和磷肥施用量对大豆结瘤和产量影响的研究较少。本试验采用裂区田间试验,设置3个氮（N）水平（0、20 和 50 kg/hm2）和 3 个磷（P）水平（0、 20 和 40 kg/hm2）,研究氮、 磷及其交互作用对大豆生长发育、 结瘤特征及产量的影响。结果表明, 单施氮肥大豆生物量和产量随着施氮量的增加而增加,而根瘤数量、 干重、 大小和结瘤指数呈逐渐下降的趋势。单施磷肥促进大豆生物量、 产量、 根瘤数量、 干重、 大小和结瘤指数的增加,但其增幅低于施氮处理下的增幅。氮磷对大豆生长和产量促进作用高于单施氮和单施磷处理,但差异不显著;氮磷处理下的根瘤数量、 干重、 大小和结瘤指数低于单施磷处理;氮磷处理下N2（N 50 kg/hm2）处理下的大豆根瘤数量、 干重、 大小和结瘤指数高于N1处理（N 20 kg/hm2）下的,随着施磷量的增加大豆根瘤数量、 干重、 大小和结瘤指数增加,施磷能够抵消氮对大豆根瘤产生和形成的抑制。氮、 磷及其交互作用对大豆根瘤的影响都是直接的,并且不是通过促进大豆生长间接促进的。因此氮和磷均是限制东北地区大豆结瘤和产量的因素,但氮是主导因素。若要获得大豆高产,氮肥施用量需要控制在50 kg/hm2,磷肥在40 kg/hm2;但若想最大的发挥大豆的结瘤固氮功能,那么应该不施或者减少氮肥的施用量到20 kg/hm2,磷肥仍在40 kg/hm2。  相似文献   

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