Improving productivity and nutrients uptake of wheat plants using Moringa oleifera leaf extract in sandy soil

A field experiment was conducted on a sandy soil at Salhia El-Gdida, Al Sharqia government, Egypt, to study the effect of Moringa leaf extract on yield and nutrient uptake of wheat plants (Triticum aestivum cv.). Foliar spraying of Moringa leaf extract was done at 40, 70, and 90 days after planting at a rate of 0%, 1%, 2%, 3%, and 4%. Treatments of Moringa extract significantly increased straw and grain yield, biological yield, 1000 grain weight, yield efficiency, protein content, and nutrient uptake as compared to untreated plants in the both seasons. The highest values of straw and grain yield, quality yield, and nutrient uptake by plants were obtained with 4% of Moringa extract, while the lowest values were obtained with untreated plants. Also, the highest percentage increase in grain yield of 71% and 88% was recorded from the treatment 4% of Moringa extract in first and second seasons, respectively.     

Moringa oleifera Lam. leaf extract as bioregulator for improving growth of maize under mercuric chloride stress

The contamination of agriculture soils with heavy metals is increasing due to both natural and anthropogenic activities. This has resulted in lowering the yield and quality of agriculture crops. The aim of the present investigation was to determine the effect of Moringa oleifera (M. oleifera) aqueous leaf extract (MALE) on growth and Hg phytoextraction potential of maize cv. Azam under mercuric chloride (HgCl₂)-induced stress. Soil was contaminated with different concentrations of HgCl₂ (1 and 0.5?mg/kg). The MALE was applied at 5% and 2.5% as seed soaking prior to sowing of seeds in the pots. The M. oleifera leaf was a good source of macronutrients (Na, K, Ca and Mg) and micronutrients (Fe, Zn, Mn, Co and Ni) as well as natural phenolics. The induced HgCl₂ stress significantly reduced seed germination (%), shoot dry weight, root dry weight, chlorophyll content and carotenoids content. The HgCl₂-induced stress was associated with accumulation of phenolics and Hg in roots. The accumulation of Hg in roots was significantly correlated with phenolics content (r?=?.8007, p?=?.000). The exogenous application of MALE significantly ameliorated adverse effects of HgCl₂ stress on maize plants. The accumulation of Hg in roots was significantly increased by MALE. It is inferred from findings of the present investigation that MALE served as bioregulator and can be applied to reduce adverse effects of HgCl₂ on maize. Moreover, MALE can enhance the Hg phytoremediation potential of maize.     

盐胁迫下氮素形态对油菜和水稻幼苗离子运输和分布的影响

【目的】土壤盐碱化是制约农作物产量的主要因素之一,盐胁迫影响养分运输和分布,造成植物营养失衡,导致作物发育迟缓,植株矮小,严重威胁着我国的粮食生产。在必需营养元素中,氮素是需求量最大的元素,NO-3和NH+4是植物吸收氮素的两种离子形态。植物对盐胁迫的响应受到不同形态氮素的调控,研究不同形态氮素营养下植物的耐盐机制对提高植物耐盐性及产量具有重要的意义。【方法】本文以喜硝植物油菜(Brassica napus L.)和喜铵植物水稻(Oryza sativa L.)为试验材料,采用室内营养液培养方法,研究了NO-3和NH+4对Na Cl胁迫下油菜及水稻苗期生长状况、对Na+运输和积累的影响,以对照与盐胁迫植株生物量之差与Na+积累量之差的比值,评估Na+对植株的伤害程度。【结果】1)在非盐胁迫条件下,硝态氮营养显著促进油菜和水稻根系的生长;盐胁迫条件下,油菜和水稻生物量均显著受到抑制,Na Cl对供应铵态氮营养植株的抑制更为显著。2)盐胁迫条件下,两种供氮形态下,油菜和水稻植株Na+含量均显著增加,硝态氮营养油菜叶柄Na+显著高于铵态氮营养,叶柄Na+含量/叶片Na+含量大于铵营养油菜,硝态氮营养水稻根系Na+含量显著低于铵营养,地上部则相反。3)铵营养油菜和水稻Na+伤害度显著高于硝营养植株。4)盐胁迫条件下,硝态氮营养油菜地上部和水稻根系K+含量均显著高于铵态氮营养。5)盐胁迫条件下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株。【结论】与铵营养相比,硝营养油菜和水稻具有更好的耐盐性。硝态氮处理油菜叶柄Na+显著高于铵态氮处理,能够截留Na+向叶片运输。同时,供应硝态氮营养更有利于油菜和水稻吸收K+,有助于维持植物体内离子平衡。盐胁迫下,硝营养油菜和水稻木质部Na+浓度,韧皮部Na+和K+浓度及水稻木质部K+浓度均高于铵营养植株,表明硝态氮营养油菜和水稻木质部-韧皮部对离子有较好的调控能力,是其耐盐性高于铵营养的原因之一。     

Enhancing growth,yield, biochemical,and hormonal contents of snap bean (Phaseolus vulgaris L.) sprayed with moringa leaf extract

Increasing growth and productivity of food crops via safe biostimulants is a very important issue in the current years. This study aimed to investigate the potential of moringa leaf extract (MLE) in improving the performance of snap bean (Phaseolus vulgaris L.) cv. ‘Paulista’ under field conditions. Hormonal analysis of MLE revealed its richness of various classes of phytohormones particularly salicylates. The results revealed that all MLE concentrations had a positive effect on growth, biochemical, yield, and yield related traits as well as yield quality of snap bean compared to control, and the effect was dose-dependent. Moreover, increasing pods yield of snap bean may be related to gibberellins (GA₇) content than other plant hormones. In conclusion, the leaf extract of moringa provides a good source of phytohormones that have a positive role to stimulate growth and productivity of snap bean plants.     

Using Moringa oleifera extract as biostimulant enhancing the growth,yield and nutrients accumulation of pea plants

Trials on the potentials of moringa for organic farming have shown that leaves contain substances, which when sprayed on crops enhance growth and yield of crops. Moringa is nutrient-rich plant with combination of antioxidants, amino acids, nutrients, potassium (K), calcium (Ca), iron (Fe) and vitamins. A field experiment was conducted on a sandy soil conditions at Salhia El-gdida county, El-Sharkia Government, Egypt during the growth seasons of 2014/2015 to study the effect of moringa leaves extract (MLE) at different rates on yield and nutrient accumulation of pea plants (pisum sativum L.). Foliar spraying of MLE was done in three equal doses at 25, 35 and 45 after planting at a rate of 0%, 1%, 2%, 3% and 4%. All treatments of MLE significantly increased fresh pods yield, shoot and seeds dry weight, biological yield, 100 seed weight, yield efficiency, protein content and nutrient accumulation as compared to control. The highest values of photosynthetic pigments, growth parameters and nutrient accumulation of plants were obtained with 4% of MLE. Also, the highest percentage increase in fresh pods yield and protein content of 82.5% and 45%, respectively, was recorded from the treatment of 4% MLE.     

施磷量对小麦物质生产及吸磷特性的影响

在低磷土壤条件下,以中筋小麦扬麦12号和弱筋小麦扬麦9号为材料,研究了施磷量对小麦物质生产和吸磷特性的影响。结果表明,在施磷量(P2O5)0～180.kg/hm2范围内,植株对磷的吸收量、吸收速率和磷的积累量随施磷量增加而上升;以施磷量108.kg/h2处理的叶面积指数(LAI)、植株茎蘖数、茎蘖成穗率、干物质积累量、花后干物质积累量和子粒产量最高。当施磷量超过108.kg/hm2时,相关物质生产指标则呈下降趋势,说明即使在缺磷土壤上,施磷量有其适宜值。小麦一生对磷的吸收存在两个高峰,出苗至越冬始期为第一个吸收高峰,拔节至孕穗期为第二个吸收高峰。植株磷素积累量的70%～75%是在拔节后吸收,表明拔节期施磷对满足小麦第二个吸磷高峰和磷的最大积累期需磷有重要意义。     

Nutrient Uptake,Water Relations,and Yield Performance lf Different Wheat Cultivars (Triticum aestivum L.) under Salinity Stress

A pot experiment was conducted in the wire house of Department of Crop Physiology, University of Agriculture, Faisalabad to evaluate the effect of salinity stress on water relations, nutrient uptake and yield of six local spring wheat cultivars. The seeds were sown in plastic pots (25 × 15 cm) and experiment was laid out in a randomized complete block design in factorial arrangement with three repeats. De-ionized water was used as control treatment while salinity stress was imposed by irrigating plants with sodium chloride (NaCl) solution of 10 mM at tillering, stem elongation, anthesis, and grain development stages. Results of the study demonstrated that salinity stress decreased water potential by 32%, osmotic potential by 12%, and relative water contents by 20% as compared to control treatment. The nitrogen (N) uptake was decreased by 36% under salinity stress, while phosphorous (P) and potassium (K) uptake were decreased by 56% and 42%, respectively. The yield of wheat plants was also significantly reduced under salinity stress. It reduced grain yield by 25% and grain weight by 7%. The response of different cultivars was also different to salinity stress as cultivars ‘Lasani-08’ and ‘FSD-08’ were found to be more tolerant as compared to other cultivars.     

Effects and rates of broiler and layer manures on the leaf yield and tissue nutrient contents of moringa (Moringa oleifera Lam.) in Swaziland

Abstract

Moringa (Moringa oleifera Lam) has been gaining increasing attention in Swaziland as a medicinal plant increasingly being exploited due to its medicinal value especially amongst people living with HIV/AIDS. The tree is being cultivated in most homesteads and fertilized using poultry manure. A pot experiment was conducted in the greenhouse during the 2016/2017 cropping season. The aim was to investigate the effects two sources of manure (i.e. broiler and layer) at five rates (0, 15, 30, 45 and 60 tonnes/ha) on dry matter yield (i.e. leaves, petioles, stems and roots) and tissue nutrient contents of moringa. The experimental design was a randomized complete block design (RCBD) in a factorial arrangement with four replicates. Data collected (i.e. number of leaves/plant, dry matter of leaflets, stems, roots and tissue nutrients- Fe, Mn, Zn, Cu and Cd) were analyzed using Statistical Analysis Software. Results showed that the application of broiler and layer manures at different rates had no significant effect (p?>?0.05) on the number of leaves/plant. The dry matter yields were significantly different considering the sources and rates of manure applications. Furthermore, results showed that the tissue nutrient contents of micronutrients (i.e. Fe, Mn, Zn and Cu) and Cd were generally higher than the maximum permissible limits (MPL) of the World Health Organization as well as daily dietary intake for medicinal plants. Evidence from this study suggest that moringa can successfully be grown using poultry manures however, the application of the aforementioned manures was found to result in elevated contents of micronutrients and cadmium in plant tissue which may be harmful for human consumption.     

长期定位施肥对冬小麦干物质生产、产量形成及钾素吸收分配的影响

采用田间试验、室内分析与数理统计相结合的方法研究了潮土区长期定位施肥对冬小麦干物质生产、产量形成及钾素吸收分配的影响。结果表明,长期施用化肥(NPK),有机无机肥配施(MNPK),无机肥配合秸秆还田(SNPK)均能显著提高冬小麦茎蘖数、地上部干物质积累量、籽粒产量及钾素积累量,但三者之间并无显著差异。冬小麦吸钾量在整个生育期内呈"低-高-低"单峰曲线变化,在扬花期至灌浆前期达最大值,拔节期吸钾量与冬小麦生长关系最为密切,与产量、地上部干物质积累量、穗数、穗粒数、株高及穗长均呈显著正相关。冬小麦在生育后期存在钾素外排现象,外排的钾素量达43.05～114.81kg/hm2,是冬小麦成熟期钾素积累量的1.55～3.09倍,冬小麦生育后期钾素管理不容忽视。     

Comparative effects of compost and NPK fertilizer on vegetative growth,protein, and carbohydrate of Moringa oleifera lam hybrid PKM-1

A field study evaluated the effects of NPK (21:17:17) and compost on vegetative growth, proteins, and carbohydrates of Moringa oleifera. The experimental design was randomized complete block design (RCBD) with six treatments replicated three times. Compost and NPK fertilizers were applied together which include control (without fertilizer) 5 t ha^?1 (Compost), 120 kg ha^?1 (NPK), 50 + 50% ha^?1 (NPK + Compost), 10 + 50% ha^?1 (NPK + Compost), and 50 + 10% ha^?1 (NPK + Compost) per plot. For NPK fertilizer, the rate was 10 and 50% of 120 kg ha^?1 and for compost it was 10 and 50% of 5 t ha^?1. The measured growth parameters were plant height (cm), stem girth (mm), number of leaves, and number of branches per plant. Results showed that 120 kg ha^?1 (NPK) treatment produced plants of more height, stem girth, more number of leaves, maximum number of branches as compared to other treatments at week 8 with higher protein. Carbohydrate content was high in 50 + 50% (NPK + Compost) compared to others.     

Seed Treatment to Overcome Salt and Drought Stresses During Germination in Safflower (Carthamus tinctorius L.)

Although safflower is drought and salt tolerant, it is susceptible to drought and salinity at the germination and seedling stages. Priming techniques have been used to overcome salinity and drought tolerance at germination stage. Osmopriming potassium nitrate (KNO₃) and hydropriming were used to determine drought [by polyethylene glycol (PEG)-6000 at water potentials of 0, ?0.3 and ?0.6 MPa] and salt electrical conductivity (EC) (values of the sodium chloride (NaCl) solutions were 0, 6 and 12 ds.m^?1) tolerance of primed seeds of safflower. Germination index, shoot/root ration, germination uniformity, days to 50% germination (D50) and abnormal germination percentage were measured. Treatment 0f seeds with hydropriming increased germination index, shoot/root ration and germination uniformity, while decrease days to 50% germination under salt and water stress. Seed treated with KNO₃ reduced abnormal germination percentage in salt stress. KNO₃ improved germination uniformity and germination index of the low water potentials. As salinity increased, germination index and shoot/root ration were decreased, while germination uniformity, days to 50% germination and abnormal germination percentage were increased. Hydropriming enhanced germination under both salt and drought stresses and non-stress conditions. Therefore, hydropriming could be used to improved seed performance of safflower under saline and drought stress. This treatment dose not needs expensive chemicals or sophisticated equipment.     

Arbuscular mycorrhizal fungi affect the growth,nutrient uptake and water status of maize (Zea mays L.) grown in two types of coal mine spoils under drought stress

Drought stress greatly affects the growth and development of plants in coal mine spoils located in the Inner Mongolia grassland ecosystem. Arbuscular mycorrhizal fungi (AMF) can increase plant tolerance to drought. However, little is known regarding the contribution of AMF to plants that are grown in different types of coal mine spoils under drought stress. To evaluate the mycorrhizal effects on the drought tolerance of maize (Zea mays L.) grown in weathered (S1) and spontaneously combusted (S2) coal mine spoils, a greenhouse pot experiment was conducted to investigate the effects of inoculation with Rhizophagus intraradices on the growth, nutrient uptake, carbon:nitrogen:phosphorus (C:N:P) stoichiometry and water status of maize under well-watered, moderate and severe drought stress conditions. The results indicated that drought stress increased mycorrhizal colonization and decreased plant dry weights, nutrient contents, leaf moisture percentage of fresh weight (LMP), water use efficiency (WUE) and rehydration rate. A high level of AMF colonization ranging from 65 to 90% was observed, and the mean root colonization rates in S1 were lower than those in S2. In both substrates, inoculation with R. intraradices significantly improved the plant growth, P contents, LMP and WUE and decreased the C:P and N:P ratios of plants under drought stress. In addition, maize grown in S1 and S2 exhibited different wilting properties in response to AMF inoculation, and plant rehydration after drought stress occurred faster in mycorrhizal plants. The results suggested that inoculation with R. intraradices played a more positive role in improving the drought stress resistance of plants grown in S2 than those grown in S1. AMF inoculation has a beneficial effect on plant tolerance to drought and effectively facilitates the development of plants in different coal mine spoils.     

滴灌磷钾肥基追比对滴灌玉米干物质积累、产量及养分吸收的影响

通过田间小区试验,研究了磷钾肥滴灌追施对玉米干物质、产量及养分吸收的影响。结果表明,磷钾肥部分基施、部分滴灌追施玉米的生物量和产量要优于磷钾肥全部基施,其中磷肥75%基施和25%滴灌追施比磷肥全部基施的玉米干物质提高4.36%,产量增加8.14%;钾肥50%基施和50%滴灌追施比钾肥全部基施的玉米干物质增加4.86%,产量增加4.98%。磷钾肥部分基施、部分滴灌追施显著提高了玉米氮、磷、钾的吸收量和利用率,其中磷肥75%基施和25%滴灌追施的氮、磷、钾肥的利用率分别为46.65%、28.42%、46.33%,比磷肥全部基施分别提高了6.0、8.44和8.95个百分点;钾肥50%基施和50%滴灌追施的氮、磷、钾肥的利用率分别为45.46%、27.92%、46.95%,比钾肥全部基施分别提高了4.26、0.99和11.89个百分点。     

Effect of shade and level of fertilizer application on nutrient uptake and dry matter partitioning in cocoyam (Xanthosoma sagittifolium L.)

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.     

膜下滴灌水氮耦合对棉花干物质积累和氮素吸收及水氮利用效率的影响

在膜下滴灌条件下,设3个氮素水平和2个水分水平,研究了水氮耦合对棉花干物质积累、氮素吸收及产量、水氮利用效率的影响。结果表明,增加水分或氮素供应,花铃期根冠生物量和氮素吸收增加; 增加灌水量,吐絮期地上部干物质和氮素积累量增加,根干物质积累量在低氮或高氮下增加,中氮降低; 产量和氮素利用效率增加,水分利用效率下降。水分胁迫条件下,增加氮素的供应吐絮期地上部干物质、氮素积累量、产量差异不大,根干物质积累量以N276处理最高,氮素利用率下降,水分利用率增加。水分充分条件下,增加氮素的供应吐絮期根干物质下降,地上部干物质、氮素积累、产量和水氮利用效率以N276处理最高。水分不足或高氮限制了干物质在花铃期至吐絮期的积累、导致棉花提早衰退,引起产量下降。     

苗期渍水和氮肥用量对直播冬油菜产量及氮肥利用率的影响

【目的】秋涝是冬油菜生产中的常见限制因子,本研究通过大田试验研究苗期渍水和氮肥用量对直播冬油菜产量及氮肥利用率的影响,以期为渍水胁迫下直播冬油菜氮肥合理施用提供理论依据。【方法】 选用华油杂9号为试验材料,采用直播栽培方式。两因素裂区试验设计,主处理为土壤水分状况,包括排水处理和苗期渍水处理,副处理为6个氮肥水平,施氮量分别为0、60、120、180、240和300 kg/hm2。研究各试验处理直播冬油菜在苗期、薹期、花期和成熟期的生长状况,各时期的干物质、氮素累积以及氮肥利用效率,同时对籽粒产量及其构成因素做了相应调查。【结果】 苗期渍水明显抑制了直播冬油菜生长发育和产量形成。相同氮肥水平下,与排水处理相比,渍水处理冬油菜各生育期叶片数、叶面积和SPAD值均有不同程度下降,生育期干物质量降幅为19.1%~26.5%,收获指数减少了5.2个百分点。渍水处理显著降低了籽粒产量,减产达23.6%,成苗密度和单株角果数下降是引起产量降低的重要原因,分别下降7.6%和20.4%。此外,渍水处理明显影响了冬油菜氮素吸收,渍水处理冬油菜生育期植株氮含量较排水处理下降了8.0个百分点,氮素累积量降幅为23.2%~32.4%。渍水处理引起了氮肥偏生产力、农学利用率和表观利用率的下降,降幅分别为22.8%、20.4%和18.6%。氮肥可以缓解苗期渍水造成的产量损失,并且缓解效应与氮肥投入量存在直接关系。施氮显著提高了冬油菜叶片数、叶面积和SPAD值,增加了冬油菜成苗密度,提高了冬油菜氮素含量,改善了群体质量,进而提高了籽粒产量,降低了油菜产量的相对受害率（RIR）,其中产量相对受害率随施氮量增加从35.3%下降到13.8%。高氮量（240~300 kg/hm2）水平下各时期干物质量和氮素累积量的下降幅度显著低于中低施氮量（0~180 kg/hm2）,其中高氮量水平下平均降幅分别为9.5%和15.0%,而中低氮水平下的平均降幅分别为27.6%和32.9%。一定范围内增施氮肥对苗期渍水后直播冬油菜生长恢复具有很好的补偿效应。在保证产量（2500 kg/hm2）不下降的情况下,排水处理要比渍水处理节省氮肥59.2 kg/hm2。【结论】 苗期渍水胁迫对油菜生长的抑制不仅作用于渍水期,其负面效应同样会延伸至整个生育阶段,最终导致产量损失。施氮可以明显缓解渍害的负面效应,优化冬油菜群体质量,实现高产。因此,合理氮肥用量和实时排水可以达到施氮减渍和排水减氮的双重效果。     

Foliar-applied trehalose modulates growth,mineral nutrition,photosynthetic ability,and oxidative defense system of rice (Oryza sativa L.) under saline stress

A tub experiment was conducted to assess the effect of exogenously applied trehalose (0, 10, and 20 mM) on various attributes of two rice cultivars (Bas-385 and Bas-2000) under salt stress (0, 50, 100, and 150 mM). Salinity decreased growth, gas exchange characteristics, shoot and root potassium (K⁺) ions, hydrogen peroxide (H₂O₂), total soluble proteins, activity of catalase (CAT), and yield attributes, while it increased chlorophyll contents, shoot and root sodium (Na⁺) and calcium (Ca²⁺), malondialdehyde (MDA), glycinebetain (GB), free proline, and peroxidase (POD) activity. Foliar-applied trehalose improved growth attributes, net photosynthetic rate, GB, total soluble proteins, superoxide dismutase (SOD) and yield. Yield was not obtained at 150 mM salt stress. The rice cultivar Bas-2000 showed better performance with respect to gas exchange attributes and activities of enzymatic antioxidants. Overall, varying levels of foliar-applied trehalose proved to be effective in ameliorating adverse effects of salt stress on rice.     

氮肥运筹对晚稻产量和氮素利用率的影响

用杂交水稻中优679为试验材料,研究氮肥运筹对晚稻产量和氮素利用率的影响。结果表明,在目标产量7 500 kg/hm2,总施氮量150 kg/hm2条件下氮肥运筹不同处理中,以基蘖肥∶穗肥=6∶4且基肥采用碳铵深施方式,其实际产量、齐穗后干物质生产量、成熟期干物质积累量、氮素利用率等均为最高。     

氮肥运筹对棉花干物质积累、氮素吸收利用和产量的影响

通过膜下滴灌田间试验,研究不同氮肥运筹模式对棉花干物质积累、氮素吸收利用及产量的影响。结果表明,各处理棉花干物质及氮素积累均符合Logistic方程;棉花干物质积累最快时期出现在出苗后83～139 d。不同的氮肥运筹可明显影响到棉花氮素吸收最大速率及其出现日期,以有机无机氮肥配施（N2+M）处理的氮素吸收最大速率较高,且其出现日期相对较早。棉株对干物质分配中心与氮素吸收分配中心一致。各施氮处理氮肥利用率在32.11%～49.24%之间,N2+M处理氮肥利用率最高,其它处理氮肥利用率随施氮量的增加而降低。本试验中,N2+M处理产量达1890 kg/hm2,显著高于其它处理。     

Nitrogen application in direct wet-seeded rice under alternate wetting and drying irrigation condition: Effects on grain yield,dry matter production,nitrogen uptake and nitrogen use efficiencies

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.