Effect of Neem Leaf (Azadirachta indica L.) on Growth and Yield of Low Land Rice

The farmers of tropical Asia are applying neem leaves to rice fields as green manure traditionally. Neem cake blending of urea is recommended for inhibition of nitrification and increasing nitrogen use efficiency. Field experiment conducted at the Tamil Nadu Agricultural University, Coimbatore, India, during kharif and rabi seasons in 1984–85 with a short duration (105 days) rice cv. IR 50 showed that application of fresh neem leaf at 5 t/ha or dry neem leaf 1.25 t/ha with urea resulted in higher N recovery per cent and N response ratio and gave increased grain yield compared to the yield obtained due to the application of urea alone. Besides increasing the grain yield, neem leaf application could save about 50 per cent N application and give greater net returns to the farmer.     

Effect of Integration of Fertilizer and Green Manure Nitrogen on Yield Attributes, Nitrogen Uptake and Yield of Lowland Rice (Oryza sativa L.)

Field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, India, during the wet seasons of 1992 and 1993 to study the effect of full and partial substitution of fertiliser N with green manure N (Sesbania rostrata) on nitrogen uptake, yield attributes and yield of rice. The experiment consisted of eight treatments with two levels of N (100 and 200 kg ha⁻¹) and three sources of N application viz., fertilizer, integrated (1:1 fertilizer and green manure N) and green manure N compared to the recommended practice (150 kg fertilizer plus 6.25 t ha⁻¹ (72 kg N) green manure) and a no N control. Nitrogen application markedly increased the N uptake. Combined use of the two N sources at 200 and 222 kg N ha⁻¹ and of single fertilizer N at 200 kg N ha⁻¹ recorded the maximum N uptake, increased the yield attributes such as number of panicles per unit area, weight per panicle, number of total and filled grains per panicle and test weight. At 200 kg N ha⁻¹ full substitution of N by green manure reduced the grain yield but only partial substitution of N by green manure resulted in almost similar yield as single fertilizer N. Thus 200 kg N ha⁻¹ applied in equal proportions of fertilizer and green manure N can be recommended for medium duration rice cultivars.     

N肥和栽插密度对杂交稻“两优培九”产量及N素吸收利用的影响

以两系杂交稻两优培九为试材,研究不同N肥用量(纯N 0、112.5、225.0、337.5 kg/hm²)和栽插密度（22.5×10⁴、27.0×10⁴、31.5×10⁴穴/hm²）对产量形成及N素吸收利用的影响。结果表明,(1)栽插密度对结实率和千粒重影响较小,对单位面积穗数和每穗粒数影响较大,在22.5×10⁴~31.5×10⁴穴/hm²的密度范围内,穗数与每穗粒数之间具有良好的互补性,因而产量差异未达显著水平。(2)N肥用量对每穗粒数影响较小,对穗数、结实率和千粒重影响较大,纯N用量为337.5 kg/hm²时,增穗作用不显著,反而极显著降低结实率和千粒重,导致减产。(3)稻株吸N量随供N水平的提高而增加,但植株含N率和N素累积量过高不利于叶鞘茎中的N素向穗部运转,降低籽粒N素积累量,导致结实率和千粒重显著下降而减产。(4)在中等肥力土壤上,施纯N 225.0 kg/hm²,栽插密度22.5×10⁴穴/hm²,高峰苗控制在500.0万/hm²左右,有利于两优培九抽穗前茎鞘叶N素积累和抽穗后向穗部运转,能较好地协调穗数、结实率和千粒重的关系而获得高产。     

Optimum Seed Rate and Nitrogen Fertilizer Requirement of Rice Under Semi-deepwater Ecosystem

The effect of varying seed rates (100–1000 seeds m⁻²) and nitrogen fertilizer (0–60 kg N ha_-1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi-deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m⁻² at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m⁻². The grain yield of rice was significantly higher at 400 seeds m⁻² in 1993 and at 600 seeds m⁻² in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha⁻¹ was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha⁻¹ and seeding density of 400–600 seeds m⁻², resulting in 40–50 % seedling emergence and 150–200 panicles m⁻², each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.     

高肥力土壤氮钾配施对鲜食型甘薯产量及品质的影响

为了探明高肥力土壤氮钾配施对烟薯25产量和品质的影响,采用二因素三水平完全随机区组试验设计,分别设3个N处理(0,45,90 kg/hm~2)和3个K_2O处理(0,75,150 kg/hm~2),共计9个氮钾组合处理,分别于收获期调查甘薯地上部性状,测定块根干鲜质量、Vc、淀粉、蛋白质、蔗糖、葡萄糖、果糖、Ca、Mg、Fe、Mn、Cu、Zn含量。结果表明:高肥力土壤上施用氮肥可增加甘薯蔓长、茎叶鲜质量、T/R值,并提高甘薯块根内蛋白质、葡萄糖和蔗糖的含量,高肥力土壤上施用氮肥情况下,块根干鲜质量、淀粉和果糖含量有所降低。施用钾肥能显著提高块根干鲜质量、薯干率及淀粉和葡萄糖的含量;促进了甘薯对Mg的吸收,降低了甘薯对Ca的吸收。在氮钾互作条件下,甘薯分枝数、结薯数及Vc、蛋白质、蔗糖、葡萄糖、果糖含量与不施肥处理相比均有所提高;鲜薯产量与氮肥、钾肥的施用存在交互作用,即在不施N、施K_2O 150 kg/hm~2时,甘薯产量达到最高,较不施肥处理增产10 825.5 kg/hm~2,增幅为29.2%。同时在施N 90 kg/hm~2、不施K_2O时,甘薯产量最低,较不施肥处理减产1 435.5 kg/hm~2,降幅为3.9%。因此,在高肥力土壤,应不施或少施氮肥并配施适量钾肥以期获得鲜食型甘薯的高产优质。     

盐逆境下缓/控释肥对水稻生长发育、产量和品质的影响

为探明盐逆境下缓/控释肥对水稻生长发育、产量和品质的影响，以南粳5055为材料开展盆栽试验。设置3个盐分水平：0.0g/kg(S0)、1.5g/kg(S1)、3.0g/kg(S2)和4种氮肥处理：常规尿素（F1）、有机缓释水稻专用肥（F2）、大颗粒尿素（F3）和硫包衣尿素（F4），各处理的施氮量和磷钾肥用量相同，以不施氮肥处理为对照（CK）。结果表明，盐逆境下，F2的最大茎蘖数、株高和成穗率均最高；在S0下，F2、F3和F4的产量比F1分别高出11.89%、5.58%和17.14%；在S1和S2下，F2的产量比F1分别高出30.28%和37.20%，而F3和F4的增产效果不佳。在盐逆境下，F2主要通过增加有效穗数、穗粒数和千粒重提高产量。盐逆境下穗粒重、一次枝梗的粒重、千粒重和结实率，二次枝梗的粒重和千粒重均以F2最高。盐逆境下，F2具有较高的糙米率、精米率、胶稠度和较低的直链淀粉、蛋白质含量。由本研究可得出，盐逆境下，F2的增产效果最佳，且对稻米品质具有一定的有利影响，在一定程度上能缓解盐逆境对水稻的危害。     

控释氮肥运筹对钵苗摆栽籼粳杂交稻甬优1540产量及氮肥利用的影响

研究籼粳杂交稻钵苗摆栽超高产栽培模式下适宜的控释氮肥运筹。试验于2016—2017年在安徽庐江进行,以当地高产籼粳杂交稻甬优1540为供试品种,设置控释氮肥一次性基施(single basal application of CRNF,BC)、与尿素分蘖肥配施(basal application of CRNF combined with urea top-dressing at the tillering stage,BC+TU)、与尿素穗肥配施(basal application of CRNF combined with urea top-dressing at panicle initiation,BC+PU)三种运筹模式,以尿素分次施肥(conventional high-yield fertilization,SU)和不施氮肥(0N)为对照,研究控释氮肥运筹对钵苗摆栽籼粳杂交稻产量、氮肥吸收利用及相关农艺指标的影响。结果表明,控释氮肥阶段释放基蘖肥:穗肥比例为7∶3,较传统优化氮肥运筹SU(6∶4)整体表现基蘖肥冗余,穗肥不足,因而BC和BC+TU处理显著降低了钵苗摆栽籼粳杂交稻产量和氮肥利用效率。与BC和BC+TU处理相比,BC+PU通过基肥减量和尿素穗肥配施,在保证水稻营养生长期基本氮素供应的同时,显著增加了穗分化至成熟期氮素吸收,促进了穗分化至成熟期光合物质生产能力,在稳定有效穗数和千粒重的同时,显著提高了钵苗摆栽籼粳杂交稻每穗粒数、结实率和产量,很好的匹配了钵苗摆栽籼粳杂交稻全生育期氮素需求。BC+PU两年的产量和氮肥利用率分别为12.2~13.1 t hm^-2和43.8%~44.1%,分别较BC显著提高7.4%~9.2%和48.5%~59.9%,较BC+TU显著提高8.0%~11.9%和63.9%~74.5%。另外,BC+PU的产量和氮肥利用率与SU无显著差异,但由于大幅降低了施氮人工成本,最终提高净收益6.5%~12.3%。在籼粳杂交稻钵苗摆栽超高产栽培模式下,采用70%控释氮肥+30%尿素穗肥处理可有效取代常规尿素分次施肥,获得无显著差异的水稻产量和氮肥利用效率,同时进一步提高经济效益。     

氮肥配施纳米镁对水稻产量、品质和氮肥利用率的影响

以水稻品种南粳9108为试验对象,于2019-2020年在扬州大学校内试验基地采用盆栽试验研究纳米镁（12kg Mg/hm²）在0、225、270、315kg N/hm²条件下对水稻的产量、稻米品质及氮素利用率的影响。结果表明,纳米镁的施用能有效提高产量和氮肥利用率。相同氮肥施用水平下,施用纳米镁处理的水稻产量均高于不施镁处理,2年籽粒产量分别提高2.85%~8.86%和5.22%~7.16%,单位面积穗数和穗粒数显著提高。与不施镁处理相比,施用纳米镁处理的氮肥利用率提高了4.18%~5.97%,稻米品质也有一定改善。施用纳米镁处理的稻米整精米率和蛋白质含量分别提高了3.51%和6.26%,垩白粒率、垩白度和直链淀粉含量分别降低了2.45%、2.40%和4.30%,胶稠度变化不明显。与不施镁处理相比,施用纳米镁处理的稻米食味值、峰值黏度、热浆黏度和崩解值分别提高了0.79%、1.35%、1.64%和0.48%,最终黏度降低了0.66%,但均未达到显著差异。兼顾产量和稻米品质,在225~270kg/hm²的施氮量下,施用纳米镁有利于实现水稻的高产高效优质栽培。     

氮、磷、钾肥对南方双季稻区水稻产量及产量构成因子的影响

为明确氮、磷、钾肥对南方双季稻区水稻产量及产量构成因子的影响,于2019年在广西象州县、岑溪市、龙州县（早季）及港北区、福绵区（晚季）进行田间试验。设置对照（不施肥）、全肥（180kg N+45kg P₂O₅+135kg K₂O/hm²）、缺氮（45kg P₂O₅+135kg K₂O/hm²）、缺磷（180kg N+135kg K₂O/hm²）和缺钾（180kg N+45kg P₂O₅/hm²）5个处理,于成熟期测定产量和产量构成因子。结果表明,氮、磷、钾肥对水稻产量及其构成因子均有显著影响。与全肥处理比较,缺氮、缺磷、缺钾和对照处理分别减产17.43%、6.64%、4.83%和25.58%。氮肥主要影响有效穗数和结实率,磷肥主要影响穗粒数,钾肥主要影响千粒重。水稻产量与有效穗数（r=0.544）和穗粒数（r=0.852）呈极显著正相关,与结实率的相关性不显著。     

施氮量对超级杂交稻Y两优900产量与氮肥利用率的影响

为探明施氮量对超级杂交稻Y两优900产量形成与氮肥利用的影响,于2020-2021年在湖南省浏阳市开展大田试验,研究不同施氮量(N0:0kg/hm²;N1:120kg/hm²;N2:180kg/hm²;N3:240kg/hm²)处理下Y两优900的产量以及氮肥利用率差异。结果表明,Y两优900在N2处理下2年产量分别为8.77和8.82t/hm²,高于N0和N1处理,与N3处理差异不显著。穗数和穗粒数在各施肥处理间无显著差异,结实率在N2处理下高于其他2个处理,千粒重有随着施氮量增加而增加的趋势。N2处理的总干物质积累量低于N3处理,但其收获指数高于N3处理。随施氮量的增加,各处理氮肥农学利用率和氮肥偏生产力逐渐降低。N2处理的氮肥籽粒生产效率和氮收获指数均高于N3处理。由此可见,在本试验条件(中产区)下,180kg/hm²施氮量有利于在保证超级杂交稻Y两优900高产的同时,实现较高的氮肥利用率。     

不同施肥水平对超级稻产量和肥料利用率的影响

为了给超级稻合理施用氮磷钾肥提供科学依据,以超级稻组合‘两优293’为材料,研究了氮、磷、钾不同施肥水平对超级稻产量和肥料利用率的影响。结果表明,不同施氮水平对超级稻产量和肥料利用率影响最大,其次是施钾水平,最后是施磷水平;氮、磷、钾肥合理配施能最大的提高超级稻的产量,在每公顷施N、P2O5、K2O为270 kg、150 kg、270 kg时,可得到最高产量,此时肥料的回收利用率、农学利用率最大;氮磷钾肥配合施用对超级稻产量的贡献是有效提高了肥料利用率、有效穗数、每穗总粒数和结实率。     

辽河三角洲稻区施氮水平对水稻生长发育及产量的影响

辽河三角洲单季稻区属于辽河平原水稻的主产区、高产区。长期以来,该地区主要以追加化肥来提高水稻产量,导致氮肥投入过高,利用率较低。根据水稻生育周期内对氮素的生物学响应,分析了辽河三角洲代表性水稻产区内不同氮素条件下水稻的生长发育及产量表现,以期获得适合该地区的合理氮肥推荐用量。研究表明,水稻的株高、功能叶片的SPAD值、茎蘖总量与氮素用量呈显著正相关,同时分蘖期的长短也受氮素水平的控制,即施氮量越高分蘖期越长。从产量及构成因子来看,有效穗数、穗粒数、千粒重对籽粒产量有显著贡献,中高氮处理（N210、N260、N315）的产量构成因子都处于较优水平,因此产量最高;低氮处理（N160）与极高氮处理（N420）的产量构成因子指标较差,产量显著低于中高氮处理。产量与施氮量符合线性加平台的肥料效应方程,基于该方程得出辽河三角洲地区最佳氮肥推荐用量为225kg/hm ²。由于土壤-水稻系统是一个整体,基于系统内的氮素平衡理论估算出辽河三角洲地区推荐氮素用量为221~235kg/hm ²。鉴于以上研究结果,推荐辽河三角洲地区合理氮素施用阈值为225~235kg/hm ²。     

水旱轮作下穗肥氮用量对机插粳稻生长特性及经济效益分析

为了研究水旱轮作系统中水稻氮肥减量施用技术,在高原粳稻区小麦–水稻和蚕豆–水稻模式中,以当地主栽水稻品种隆科16为材料,在不施基蘖氮肥的条件下,分别施纯氮0、90、120、150、180和210kg/hm²作穗肥,按促花肥:保花肥=6:4进行施肥,并以常规施纯氮285kg/hm²作为对照（基肥:分蘖肥:促花肥:保花肥=0.25:0.25:0.25:0.25）,分析了水稻的群体生长特性和经济效益。结果表明,2种轮作模式中,不施基蘖氮肥,只施用适量（180kg/hm²）穗肥氮,水稻产量与对照相持平。在水稻有效分蘖临界叶龄期,小麦–水稻和蚕豆–水稻模式不施基蘖氮肥处理的最低水稻分蘖数分别达到对照的91.09%和87.62%,最高分别达到对照的95.05%和91.11%,成熟期有效穗数与对照差异不显著,不施基蘖氮肥只施穗肥氮能显著提高水稻成穗率。与对照相比,施穗肥氮后水稻的有效穗数、干物质积累量和阶段增量以及群体生长速率明显加快。小麦–水稻和蚕豆–水稻模式中,穗肥氮用量为180kg/hm²处理,氮肥投入比对照减少36.84%,水稻经济效益最高,达到了节本增效的目的。     

N-Dynamik des Bodens, Ertragsbildung und Stickstoffentzug von Winterweizen bei unterschiedlicher Höhe und Verteilung der mineralischen N-Düngung

NO₃ dynamics in the soil, yield formation and N uptake of winter wheat as influenced by dosage and distribution effects of N-fertilizer application
In a 4 year series of field trials carried out with 9 regimes of nitrogen fertilizer application at two trial sites with rather shallow top soil layers but large deviations in soil characteristics, grain yield varied between 50 dt/ ha and 120 dt/ha with nitrogen doses from 0–170 kg N/ha. Soil nitrogen supply for wheat grain formation on unfertilized plots reached 80 kg N/ha/year within the narrow range of 75–95 kg N/ha in different years at both sites which amounts to 1.5 % and 0.5 % of the highly different N-content of the trial sites.
The most successful nitrogen application regimes are characterized by modest fertilizer doses in early spring and the delay of supplemental fertilizer doses until growth stage EC 32. They resulted into modest NO) soil content from EC 29 to EC 32 and/or a noticable decrease of soil NO₃ content during growth stage EC 30–32, which seems to be responsible for the development of only modest stand densities and reduced straw yield, while the delayed supplementation with nitrogen fertilizer overcompensated these effects mainly by increased grain numbers/ear and a remarkable improvement of harvest index.
The contribution of soil borne nitrogen to kernel yield formation started to decrease with even low dosages of supplemental nitrogen fertilization with the exception of the highest yielding season 1987/88. Top levels of grain yield have been regularly obtained with supplemental nitrogen fertilizer dosages about 40 kg N/ha below grain yield nitrogen extraction if they were added within favorable application regimes.     

Effect of Azolla as an Organic Source of Nitrogen in Rice-Wheat Cropping System

Increasing area under high yielding varieties require more quantity of fertilizers and other inputs for higher yield. However, utilization of available biomass could reduce the dependence on costly crop production inputs like fertilizers. In light of this, field experiments were carried out at Agricultural Engineering Department, Indian Institute of Technology, Kharagpur for two years i.e. 1982–83 and 1983–84 to find out the possibilities to meet at least a part of nitrogen requirement through incorporation of Azolla in rice-wheat cropping system. Incorporation of 10 t/ha of fresh Azolla before planting + 30 kg N/ha through fertilizer as basal proved to be the best and recorded maximum land productivity in rice-wheat cropping system. This treatment recorded 117.69 and 103.30 per cent higher grain yield of rice and wheat respectively over control. About 30 kg N could be supplemented through preplanting incorporation of 5 t fresh Azolla. The result indicated that Azolla could be utilized as an alternative source of N-fertilizer for higher production of crops in rice-wheat cropping system.     

氮肥运筹对超级杂交粳稻产量、品质及氮素利用率的影响

在高产施氮量条件下(225 kg hm-2),按基蘖肥、穗肥不同施氮比例且穗肥依不同叶龄期追氮共设计了20种施氮模式,研究了其对超级杂交粳稻常优1号产量、氮素利用率及主要米质性状的影响。结果表明:氮肥运筹对常优1号产量影响极大,基蘖肥与穗肥施氮比例为58.34∶41.66,穗肥以叶龄余数4、2叶等量施氮时,产量最高;产量与总吸氮量、氮肥农学利用率、氮肥表观利用率、生理利用率呈极显著正相关关系,氮收获指数和百千克籽粒需氮量与产量呈二次曲线关系;随着穗肥施氮比例的下降,稻米整精米率、蛋白质含量、垩白率、垩白度逐渐下降;胶稠度、直链淀粉含量呈直线上升趋势;穗肥随追肥叶龄期推迟,整精米率、蛋白质含量提高,而直链淀粉含量下降。胶稠度、外观品质因基蘖肥施氮比例的不同而异。综合来看,基蘖肥、穗肥施氮比例为6∶4,穗肥以倒4、2叶期追肥可使该品种超高产、优质、高效得到较好的协调统一。     

Effect of Sesbania rostrata on Nitrogen Uptake and Yield of Lowland Rice

Nitrogen inputs into rice fields can be increased by cultivation of green manure crops. Many Sesbania species have been generally grown by the rice farmers in India and these green manures are capable of contributing significant amount of nitrogen in 45 to 90 days period by their association with the nitrogen fixing symbiotic bacterium – Rhizobium . Field experiments conducted at the Tamil Nadu Agricultural University, Coimbatore, India, during Dry and Wet seasons in 1987–88 with medium duration (145 days) rice variety CO 43. Sesbania rostrata produced higher biomass on 60th day after sowing and accumulated higher percentage of nitrogen. Application of fertilizer nitrogen with S. rostrata have increased the nitrogen uptake and yield of rice.     

氮硅互作对水稻营养和产量的影响

为氮硅合理配施提供充分的理论依据,通过小区试验研究了氮硅互作对水稻营养与产量的影响。结果表明,施硅可明显增加穗实粒数与千粒重,而施氮可明显增加有效穗数,氮硅配施可以提高水稻产量。增施硅肥可明显提高土壤有效硅含量,而施氮明显降低了土壤有效硅含量。施氮对水稻各时期氮磷钾含量提高有促进作用,而施硅则影响不显著。说明氮硅配施具有相互平衡作用,中氮水平下(180 kg/hm2)配施SiO2 30 kg/hm2水稻营养较为均衡,产量最高。     

氮、钾施用量对中粳稻群体质量和产量的影响

以中粳品种“皖稻68”为材料,研究N、K施用量对单季中稻群体质量和产量的影响。结果表明,在施N量为262.5kg/hm2和施kcl为375.0kg/hm2时产量最高,达11211.1kg/hm2。水稻的总茎蘖数、叶面积指数、干物质积累量、有效穗数和每穗粒数随着施氮量的增加而增高,而分蘖成穗率、有效和高效叶面积率、抽穗后干物质生产积累量和总颖花量以施N量为262.5kg/hm2为最高,进一步增施氮肥则下降,不利于群体质量的提高。钾肥对水稻的有效穗和穗粒数影响不大,但能提高结实率和千粒重,随着施钾量的增加,穗下节间长度占株高的比例增加,有利于提高植株抗倒性,而抽穗后干物质生产积累量也随着施钾量的增加而增加,水稻的群体质量得到优化,产量有增高的趋势,但是不显著。     

施肥方式和施氮量对川西平原机插稻产量和氮肥利用的影响

为研究施肥方式和施氮量对川西平原机插稻产量形成和氮肥利用的影响,本研究以‘天优华占’为材料,采用裂区试验设计,主区因素为2种施肥方式（人工撒施和机械侧深施）;副区因素为2种施氮量（180 kg/hm2和144 kg/hm2,分别记为N180和N144）。分析各处理水稻齐穗期和成熟期干物质积累量、产量及产量构成因素。结果表明：机械侧深施肥能够显著提高川西平原单季稻产量及氮肥利用率。与人工撒施处理相比,机械侧深施处理有效穗、每穗粒数、产量、氮肥偏生产力和氮肥农学利用率分别增加0.39%、6.60%、4.97%、4.79%和18.54%。侧深施肥条件下,N180处理干物质积累量、有效穗数和籽粒产量显著高于N144处理。180 kg/hm2氮肥撒施处理的产量比144 kg/hm2氮肥机械侧深施处理增加2.87%。可见,机械侧深施技术既能降低施肥成本,又能稳产,值得大面积推广应用。