Ha-1 Nitrogen Research Articles

Response of yield and nitrogen use efficiency to aerated irrigation and N application rate in greenhouse cucumber

Excessive irrigation and fertilization in greenhouse cultivation have a major negative impact, causing economic and environmental problems. Efficient water and fertilizer management methods to increase water use efficiency (WUE) and nitrogen use efficiency (NUE) have been studied often in greenhouses where vegetables are cultivated. However, optimizing the application of nitrogen under certain water conditions does not continue to increase yield. This may be due to oxygen deficiency caused by water saturation in the root zone after irrigation. Aerated irrigation (AI) may be an effective management measure to further reduce the application of nitrogen fertilizer and increase the yield. In order to determine the interaction among irrigation water aeration and N application, a greenhouse study was conducted in Yangling, China, setting up two irrigation methods(AI and drip irrigation)and three N application rates (0, 240, 360 kg ha−1). In this study, AI significantly improved the nitrogen use efficiency (NUE) and yield of cucumber (Qiande 777, p < 0.05). As compared to drip irrigation, the partial factor productivity of applied N (PFP) under AI increased 28.95 % and 18.53 % at 240 and 360 kg N ha-1 nitrogen levels, respectively; cucumber yield under AI was 17.50 % higher than that with drip irrigation condition. AI and N application significantly improved crop yield: the highest yield obtained at AI and nitrogen reduction treatment (I1N2) was 72.3 t ha−1, which was 1.19 and 1.29 times higher than that of non-aerated nitrogen reduction (I0N2) and conventional nitrogen application (I0N3) (p < 0.05). Therefore, AI along with nitrogen application of 240 kg ha−1 is recommended for greenhouse cultivation of cucumber.

Evaluation of nitrogen (Urea) on Zea mays L. under Balkh province climate

An experiment was conducted to evaluate effect of urea fertilizer on yield and yield components of Zea mays L. Using Randomized Complete Block Design (RCBD) split plots in three replications in agricultural research farm of Balkh University by 2019. Doses of urea used in this experiment were 0, 80, 160 and 240 kg ha-1 , respectively. It has been found that amount of nitrogen fertilizer (urea) had significant effect on yield of maize at p&lt;0.05. The higher level of nitrogen caused the higher grain yield, number of kernels per ear, the number of grains per ear row, ear diameter, cob length, grain per plant and plant height. As a result 7.76 ton ha-1 was recorded as high yield while 240 kg ha-1 urea was used, and 5.12 ton ha-1 was recorded as low yield in treatment one with 0 kg ha-1 of nitrogen fertilizer. Finally, as a result using 240 kg ha-1 nitrogen fertilizer is recommended.

Nitrogen sources on yield, mineral nutrition and bromatology of Cyclanthera pedate

ABSTRACT Caygua fruits (Cyclanthera pedata) are used both in cooking and for medicinal purposes. However, few studies on this species, considered a non-conventional vegetable, can be found in literature. This study aimed to assess the responses of caygua crop to green manure and mineral nitrogen fertilization, in relation to marketable fruit productivity, nutrient content in leaves and fruits and bromatological composition. The study was carried out in a randomized block design with four treatments and five replicates: 1) control (without nitrogen); 2) 60 kg ha-1 nitrogen (urea form); 3) green manuring using Cajanus cajans and 4) green manuring using Crotalaria juncea. The plots consisted of three caygua lines with four plants per line (spacing 2x1 m). In the treatments using green manure, three lines of these respective legumes were cultivated. We evaluated marketable fruit productivity, nutrient contents in fruits and leaves and bromatological composition of the fruits. Production of caygua fruits was higher in the treatment consisting of urea application (23.6 t ha-1), followed by Crotalaria juncea (15.6 t ha-1), Cajanus cajans (14.8 t ha-1) and control (9.2 t ha-1). Treatments did not influence the nutrient contents in fruits and leaves and the bromatological composition. However, in relation to higher productivity, the amounts of nutrients absorbed by plants and accumulated in fruits were higher in treatments using mineral fertilization due to the higher yield. The bromatological analysis of fruits showed considerable contents of crude protein and ether extract, highlighting the potential of this species to human diet.

Nitrogen dynamic in wheat (Triticum aestivum L.) agroecosystem as influenced by intra- and interspecific competition

Abstract Background: The study of both intra- and interspecific competitions in Wheat (Triticum aestivum L.) agroecosystem is quite complex and it is essential to understand the influence of nitrogen in these competitions. Objective: The aim of this study was to evaluate the effect of different competitive models on nitrogen balance in wheat ecosystem agriculture (Chamran cultivar). Methods: A field experiment was performed using split-plot based on randomized complete block design (RCBD) with three replications. The main and sub-plots consisted of different nitrogen rates (control, 50, 100 and 150 kg nitrogen ha-1) and different competitive patterns (no, intraspecific, interspecific competition and intra- and interspecific in combination) were applied to the sub-plots, respectively. Weed density in the interspecies competition was applied through the equal planting of two narrow leaves (Avena sativa L.) and broadleaf (Sinapis arvensis L.) weed species. Results: The dry matter (DM) accumulation and nitrogen content (NC) at anthesis was higher than that at maturity stage for all competition treatments as well as nitrogen rates. The trend of nitrogen translocation efficiency (NTE) and nitrogen harvest index (NHI) was different from dry matter translocation efficiency (DMTE), and both were highest in interspecific competition treatments. Moreover, the highest grain yield in no competition treatment resulted in a lower dry matter and NTE. Conclusions: It was concluded that the capacity for nitrogen accumulation in the stem, was associated with a high nitrogen uptake, nitrogen assimilation and high post-anthesis nitrogen remobilization efficiency. In additions, high NHI could be used in the development of cultivars with the desired N balance.

Nitrogen fertilization of self-seeding Italian ryegrass: effects on plant structure, forage and seed yield

ABSTRACT: This study aimed to evaluate the effect of different levels of self-seeding Italian ryegrass (Lolium multiflorum Lam.) and nitrogen rates - applied additionally after two defoliations - on plant structure, in forage and seed yield. Levels of self-seeding were classified as very high (777 kg ha-1), high (736 kg ha-1), intermediate (624 kg ha-1), and low (234 kg ha-1). Populations were fertilized with zero, 20.25, 40.50, and 60.75 kg ha-1 of supplemental nitrogen applied after two defoliations; respectively, in very high, high, intermediate, and low levels. Higher levels of self-seeding promoted greater forage yield and uniformity of vegetation structure. Number of fertile tillers and number of seeds per plant have benefited by the combination of high self-seeding and supplemental nitrogen fertilization. Despite influencing the uniformity and amount of forage obtained in two defoliations, the very high and low self-seeding levels did not differ in Italian ryegrass seed production. However, linear addition for this same variable was obtained with the inclusion of supplemental nitrogen fertilization. In pastures from low and intermediate self-seeding levels, total dry mass increases linearly with the levels of nitrogen fertilization assessed in this research.

Organic matter of tropical soil with coffee growthin CO2 enriched atmosphere

The increase of atmospheric CO2 should result in higher carbon fixation by plants of the C3 photosynthetic cycle, such as coffee. However, not much is known about the relationship between atmospheric CO2 increase, higher carbon fixation through photosynthesis and the potential carbon sequestration in soil. Based on the hypothesis that there will be greater stabilization of carbon in soil due to increase of atmospheric CO2 concentration, the study was carried a field coffee grown area with FACE (Free-Air Carbon dioxide Enrichment) system. The CO2 enrichment treatment maintained the concentration of this gas 200 ?mol mol-1 above the ambient value. The stocks of carbon and nitrogen in soil and some attributes related to the humification of organic matter were evaluated 43 months after the beginning of the experiment. In addition, the decomposition of residues of coffee plants (leaves) and the emission of N2O were also evaluated. The stocks of carbon and nitrogen in soil of at 0-5 cm layer were in average 18% higher (2.6 Mg ha-1 carbon and 0.2 Mg ha-1 nitrogen) in CO2 enrichment treatment. As the decomposition of vegetal remains was not affected by atmospheric CO2 enrichment, the increase of carbon and nitrogen in soil was due to the greater contribution of vegetal material, which resulted in a less humic organic matter. In the equilibrium between carbon soil stabilization and N2O emission, the enrichment of atmospheric CO2 in the coffee crop resulted in negative feedback for global warming due to the increased sequestration potential of carbon by soil.

Soil Physicochemical Properties, Water Use Efficiency and Productivity of Wheat - Maize Yields under Clay Soil Conditions as Affected by Rice Straw and Compost Application

Two field experiments were implemented at El-Gemmieza Agric., Res. Station, Agric., Res., Center in El Gharbiah Governorate, Egypt through (2017/2018) seasons to investigate the impact of rice straw and compost application on soil physicochemical properties, water use efficiency and production of both wheat and maize yields. The design of experiment was complete randomized blocks design with three replicates, the experiment comprises the following treatments: T1: (control), T2: 2.50 t ha-1 (RS), T3: 5.00 t ha-1 (RS), T4: 5.00 t ha-1 (C), T5: 2.50 t ha-1 (RS) + 5.00 t ha-1 (C) and T6: 5.00 t ha-1 (RS) + 5.00 t ha-1 (C). Results showed that the applied of all organic treatments improved organic carbon, total N, C/N ratio and pH in soil when in all sample that was taken monthly at (30, 60, 90, 120, 150, 180,210, 240, 270, 300, 330 and 360 days from incubation rice straw and compost as compared to control treatment. Results show that applied T6 gave the best values of total porosity and hydraulic conductivity but the bulk density decreased than other treatments. The same trend was noticed concerning application T6 treatment which improved crops and water use efficiency of both wheat and maize as well as increased content (%) and uptake (Kg ha-1) of nitrogen, Phosphors, and potassium of grains and straw of both wheat - maize crops as compared to other treatments. It seems that the characteristics parameters of soil and plants has followed the sequence T6> T5 > T4> T3 > T2> T1.

بررسی برهمکنش تنشهای شوری، خشکی و کود نیتروژن بر عملکرد، اجزای عملکرد و برخی صفات فیزیولوژیک ذرت (.Zea mays L)

به‌منظور بررسی برهمکنش شوری، خشکی و نیتروژن بر روی برخی صفات فیزیولوژیک، عملکرد و اجزای عملکرد ذرت (هیبرید متوسط ­رس 604) آزمایشی به‌صورت کرت‌های دو بار خردشده در قالب طرح بلوک­های کامل تصادفی در سه تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه ایلام در بهار و تابستان 1396 اجرا شد. تیمارهای آزمایش شامل چهار سطح شوری (صفر، 2، 4 و 6 دسی­ زیمنس بر متر) از منبع سنگ نمک سدیم به‌عنوان عامل اصلی، سه سطح آبیاری (100، 80 و 60 درصد نیاز آبی گیاه) به‌عنوان عامل فرعی و سه سطح کود نیتروژن از منبع اوره (صفر، 100 و 150 کیلوگرم در هکتار) به‌عنوان عامل فرعی فرعی در نظر گرفته شد. نتایج نشان داد که اثر متقابل شوری، آبیاری و نیتروژن بر صفات تعداد دانه در بلال، تعداد ردیف در بلال، تعداد دانه در ردیف، عملکرد دانه، عملکرد زیستی و شاخص برداشت معنی‌دار شد. این صفات در بالاترین سطوح تنش اعمال‌شده نسبت به شرایط بدون تنش و کاربرد 150 کیلوگرم در هکتار نیتروژن، به ترتیب برابر 59، 40.6، 40، 69، 65 و 46 درصد کاهش نشان دادند.بیشترین میزان نشت یونی (45 درصد) در بالاترین میزان شوری، حداقل آبیاری و بدون مصرف نیتروژن مشاهده شد. محتوای نسبی آب برگ، کلروفیل a، b، کل و کارتنوئید نیز تحت اثرات دوگانه شوری و خشکی، در بالاترین میزان تنش اعمال‌شده به نسبت شرایط بدون تنش، به ترتیب برابر 18، 46، 32، 40 و 44 درصد کاهش یافتند. نتایج نشان داد کاربرد 100 و 150 کیلوگرم در هکتار نیتروژن در سطوح مختلف تنش، موجب کاهش اثرات تنش‌ها شد و افزایش عملکرد را در پی داشت. همچنین مشاهده شد، تمامی صفات موردبررسی در بالاترین میزان تنش‌ها، پاسخ تقریبا یکسانی به تیمار کودی 100 و 150 کیلوگرم در هکتار نیتروژن داشتند؛ بنابراین به نظر می­رسد که به جهت افزایش مقاومت گیاه ذرت و رسیدن به حداکثر عملکرد در شرایط تنش، کاربرد 100 کیلوگرم در هکتار نیتروژن نسبت به مقادیر بیشتر آن ازلحاظ زیست‌محیطی و اقتصادی مناسب­تر باشد.

Chemical attributes of soil irrigated with treated sewage effluent and cultivated with bell pepper

The use of treated sewage effluents (TSE) for irrigation purposes is a viable alternative for wastewater reuse and nutrient supply to the soil, which represent the two main environmental benefits. This work therefore evaluated the effect of the application of TSE on the quantity of nutrients added to the soil and changes in the chemical attributes of a Red-Yellow Latosol in the layer from 0.0 to 0.2 m cultivated with the bell pepper F1 Canary hybrid and surface drip irrigated. The experiment was carried out under field conditions from September 2015 to January 2016 in a randomized block statistical design with four replications, including the following treatments: river water, TSE, river water with base fertilization, TSE with base fertilization, TSE with cover fertilization, and TSE with cover and base fertilization. Irrigation of the bell pepper cultivation with TSE increased the level of potassium but did not affect the levels of phosphorus, organic matter and pH of the soil at the end of the growing cycle. The following amounts of nutrients were added to the soil by irrigation with TSE: 10 kg ha-1 of total nitrogen, 10 kg ha-1 of total potassium and 0.5 kg ha-1 of total phosphate. In general, TSE induced greater productivity of the peppers than those irrigated with river water, even when including mineral fertilization.

WATERMELON YIELD AND EFFICIENCY OF USE OF WATER AND NITROGEN

ABSTRACT The evaluation of the yield of crops and their efficiency of use of water and nitrogen is essential to optimize the management of production factors. The objective of this study is to evaluate the effect of irrigation regimes and nitrogen doses in fertigation on fruit yield and efficiency of use of water and nitrogen by the Top Gun watermelon hybrid. The study was conducted in Bom Jesus, Piauí, Brazil, from August 4 to October 15, 2015. The study used a completed randomized block design with four repetitions, five irrigation depths (110.17, 156.86, 221.16, 268.87, and 317.09 mm), and five doses of nitrogen in fertigation (0, 50, 100, 150, and 200 kg ha-1 applied as urea). Fruit yield and water use efficiency were not affected by nitrogen doses; however, there was a significant interaction of the factors for the efficiency of nitrogen use. The highest yield (39,549.45 kg ha-1) was obtained using 233.48 mm of water during the growth cycle. The water depth that promoted the maximum efficiency of water use was 110.42 mm, and nitrogen use was most efficient using 232.21 mm of water and 50 kg ha-1 of nitrogen.

Incidence of Brown Plant Hopper in the Rice Field with the Use of Different Doses of Fertilizers

The rice brown planthopper is a rice pest, which one is very harmful when the nitrogen fertilizer is applied at a higher rate. To evaluate the effect of brown plant hopper by using different fertilizers on transplanted basmati rice, a field experiment was conducted at the experimental farm of School of Agriculture, in Lovely Professional University, Punjab during Kharif season 2015–2016. The different fertilizer doses were used, and the experiment comprised of 15 treatments. The results showed that the nitrogen fertilizer did not harm to rice crop, but the attack of brown planthopper was icreased due to more succulent tissues of a rice plant. The nitrogen increased the photosynthesis effect and ratio in the plant due to more production of chlorophyll. In case of another fertilizer P and K (P2O5 and K2O) are not promoting but also nor affecting to insect/pests attack. Zinc sulfate proved that its effect was much positive towards crop because the zinc sulfate making less susceptibility of plants to pest attack at all doses. The rice crop was showed highest brown plant hopper attack at 50 kg ha-1 of nitrogen and also showed maximum plant height, number of tillers, panicles/plant, and 1000 grain weight. Maximum grain and straw yield (7093 kg/ha, 8753 kg/ha) was recorded in T9 where N- 50, P-40 kg ha-1 was applied. The grain yield and straw yield was recorded maximum in treated plots as compared to the control.

Environmental Hazards and Agronomic Benefits of Organic and Inorganic Nitrogen Fertilization to Sandy Soils Monocropped with Radish. المخاطر البیئیة والفوائد الزراعیة للتسمید النیتروجینی العضوی وغیر العضوی للأراضی الرملیة المزروعه بالفجل.

Application of organic in combinations with inorganic N fertilizers can supply plants with all necessary nutrients in slowly available forms without environmental pollution. Vegetable field trials were conducted under controlled greenhouse conditions for two successive seasons using radish as a catch crop in order to evaluate environmental hazards and agronomic benefits of applying different combinations of organic and inorganic N fertilizers to sandy soil. Over both seasons of this study, improvements in growth quality parameters of radish plants were in most cases not significantly different at the higher fertilizer application rates of 120 and 180 kg ha-1. This finding indicates that radish response as a catch crop owing to the increasing of fertilizer application rate is subjected to diminishing returns, beyond which further additions will not improve the yield but pollute soil environment.Results of this research showed that, major considerations in applying of inorganic N fertilizers alone on sandy soils monocropped with catch crops are the increase in residual nitrate in soils, the increase in groundwater contamination potentials by nitrate, and the threat of nitrates build-up in plant tissues. Under conditions of this study, high application rates of inorganic nitrogen fertilizer (180 kg ha-1) caused high levels of nitrate accumulation in radish, and on being con­sumed by human beings, pose serious health hazards. In general, at the rate of 120 kg ha-1 equal combined organic and inorganic fertilizers, no health problems could be foreseen to humans or animals from food chain movement of nitrates. From this research it could be concluded that incorporation of combined organic and inorganic fertilizers into sandy soil monocropped with catch crops at the rate of 120 kg ha-1 nitrogen using drip irrigation system was the best management strategy practice to reach optimum agronomic benefits while minimizing environmental and health hazards.

Effect of Nitrogen Rates on the Forage Yield of Maize Genotypes under Superadhesion

Maize production is directly linked to the genetic potential of the variety and management practices, among them, sowing density and soil fertility. The objective of this work was to analyze the effect of the application of nitrogen doses and its efficiency and use in maize genotypes grown under over - densification conditions, in the city of Rio Largo, Alagoas. The experiment was carried out from November 2015 to March 2016, and a randomized complete block design was used in the 3 x 4 factorial scheme (three maize genotypes: Branca, Viçosense and Nordestino, and four nitrogen doses: 80, 160, 240 and 320 kg ha-¹) with three replications, at seeding density of 167 thousand plants per hectare. The dry matter production of the forage and its qualitative characteristics were evaluated: dry matter, mineral matter, crude protein, neutral detergent fiber, acid detergent fiber and hemicellulose. Under the conditions of over-counting, it is concluded: (a) the corn genotypes Viçosense, Branca and Nordestino, for the productive and qualitative characteristics of the forage, presented similar and satisfactory behavior, except for the variable HC, where the genotype Branca stood out in relation to the others, presenting the highest levels of hemicelluloses, which gives it the highest concentrations of energy and digestibility of its forage; (b) the dose 80 kg ha-¹ of nitrogen was the most satisfactory for the productive and qualitative characteristics of maize fodder, since its effect was similar to increasing nitrogen dosages, in addition to providing a higher percentage of NDF.

Carbon Sequestration under Saffron (Crocus sativa) Cultivation as Influenced by Different Levels of Organic Manure and Inorganic Nitrogen

The effect on carbon sequestration under saffron (Crocus sativa) cultivation as influenced by different levels of organic manure and inorganic nitrogen was investigated in a field experiment at Dryland (Karewa) Agriculture Research Station, Budgam, Kashmir. The farm yard manure was applied at 0, 30 and 60 t ha-1 and inorganic nitrogen at 0, 45 and 90 kg ha-1, respectively along with Azotobacter. The organic carbon content was recorded at three stages, immediately after flowering (Oct-Nov), during vegetative growth stages in (Feb- March) and (April-May), respectively. The pooled data indicated that at stage I, there was a significant increase in the organic carbon in the soil with the application of maximum amount of FYM and nitrogen. The mean organic carbon content of the soil increased from 9.22 g kg-1 to 15.34 g kg-1 when FYM was applied in conjugation with inorganic nitrogen. However, the highest and significant organic carbon (17.50 g kg-1) was observed in the treatment in which nitrogen was applied at 90 kg ha-1 and FYM at 60 t ha-1 an increase of 156.9 per cent over the control (6.81 g ha-1). Similar trends were also observed at stage II and III, respectively. However, the effect of Azotobacter was found significant only at stage-III.

Carbon Sequestration under Saffron (Crocus sativa) Cultivation as Influenced by Different Levels of Organic Manure and Inorganic Nitrogen

The effect on carbon sequestration under saffron (Crocus sativa) cultivation as influenced by different levels of organic manure and inorganic nitrogen was investigated in a field experiment at Dryland (Karewa) Agriculture Research Station, Budgam, Kashmir. The farm yard manure was applied at 0, 30 and 60 t ha-1 and inorganic nitrogen at 0, 45 and 90 kg ha-1, respectively along with Azotobacter. The organic carbon content was recorded at three stages, immediately after flowering (Oct-Nov), during vegetative growth stages in (Feb- March) and (April-May), respectively. The pooled data indicated that at stage I, there was a significant increase in the organic carbon in the soil with the application of maximum amount of FYM and nitrogen. The mean organic carbon content of the soil increased from 9.22 g kg-1 to 15.34 g kg-1 when FYM was applied in conjugation with inorganic nitrogen. However, the highest and significant organic carbon (17.50 g kg-1) was observed in the treatment in which nitrogen was applied at 90 kg ha-1 and FYM at 60 t ha-1 an increase of 156.9 per cent over the control (6.81 g ha-1). Similar trends were also observed at stage II and III, respectively. However, the effect of Azotobacter was found significant only at stage-III.

Nitrogen Management in Maize Under Rainfed Conditions in the Brazilian Semiarid Region

Zea mays L. presents socioeconomic and cultural importance for the Northeast region of Brazil, its yield is directly related to the productive system, to the edaphoclimatic conditions and to the soil management. The aim of this work was to evaluate the development and the yield of maize under different nitrogen doses in rainfed conditions in the Brazilian semiarid. The experimental design was in randomized blocks, with four treatments and five replications, totalizing 20 experimental plots, with 24 plants each. The treatments were: T1 (0 kg ha-1 of N); T2 (40 kg ha-1 of N); T3 (60 kg ha-1 of N) and T4 (80 kg ha-1 of N). Were evaluated: plant height, culm diameter and number of leaves at 30, 45, 60, 75 and 90 days after emergence; leaf temperature, stomatal conductance, transpiration, liquid photosynthesis and intercellular carbon concentration at 65 days after emergence; yield, shoot dry mass and nitrogen content in the soil after harvest. The different nitrogen doses significantly influenced the plant height, culm diameter and the number of leaves in the different evaluation periods, also influencing the nitrogen levels in the soil after the harvest. There was no difference among treatments for the yield, the registered average was 5,205 kg ha-1. The development of the crop and the nitrogen absorption may have been influenced by the water deficit during the crop cycle. The maize presented better agronomic performance with the dose of 60 kg ha-1 of nitrogen.

Response of Lawn Grass Cultivars to Various Nitrogen Levels

A study entitled Response of lawn grass cultivars to various nitrogen levels was conduct at Cantonment Board Nursery Nowshera Cant. Khyber Pakhtunkhwa. The experiment was laid out in Randomized Complete Block Design with two factors factorial arrangement and replicated three times. Three cultivars of lawn grass (Korean grass, Australian grass, and Fine Dhaka grass) were subjected to various levels (control, 50kg ha-1, 100kg ha-1, and 150kg ha-1) of nitrogen. Urea was used as a source of nitrogen. According to the result, the application of nitrogen to different grass cultivars significantly influenced all parameters except quantity of newly emerged leaves and days to new growth.

Productivity of jambu (Acmella oleracea) using different soil water tensions and nitrogen rates under greenhouse condition

Acmella oleracea (L.) R.K. is a native Amazon vegetable, known as jambu, which is widely used in regional cuisine and has aroused the interest of the pharmaceutical and cosmetic market. Thereby, this work aimed to study the effect of different soil water tensions and nitrogen rates on Jambu cultivation in the State of Pará. The experiment was conducted in a greenhouse for 30 days in 2016 testing Jamburana cultivar in a 10 × 10 cm spacing in the experiment. The experimental design was based on randomized blocks in a 4 × 4 factorial scheme with three replications. The treatments consisted of four soil water tensions (12, 18, 24 and 30 kPa) adjusted using drip irrigation, and four doses (0, 50, 100 and 150 kg ha-¹) of nitrogen. The analyzed variables were fresh mass, plant height, productivity and water use efficiency. There was no interaction between soil water tensions factors and nitrogen rates for all variables. The results showed that the best water tension in the soil and nitrogen dose that provided better development and productivity of jambu were 18 kPa and 79 kg ha-¹, respectively.

Evaluation of Yield and Yield Attributes in Various Rice Genotypes under Different Nitrogen Levels

The experiment was conducted during 2017, Pishanam season at Rice Research Station, Ambasamudram with the objective to screen the efficient and responsive rice genotypes based on nitrogen use efficiency and yield and yield attributes of different genotypes by N levels with 32 rice genotypes as main plot treatments and four nitrogen levels N0 (control), N1 (50% recommended dose of N ha-1), N2 (100% recommended dose of N ha-1) and N3 (150% recommended dose of N ha-1) as subplot treatments. The experimental results showed that, the highest grain and straw yields were recorded at N3 (180 kg ha-1) by the most of the rice genotypes, except the AS 12051, ACK 14004, CB08702, CB 13539 and PM 12009 which were not responded genotypes for higher dose of (180 kg ha-1) nitrogen. In the genotypes ASD 16, ADT 43, ADT 45, CO 51, MDU 5, CB 14508, CB 14533, TR 0927, TR 13069 and TM 12061 the AE was increasing with increasing level of nitrogen, other genotypes showed decreasing trend with increasing level of nitrogen levels. The genotypes viz., ASD16, ADT39, ADT45, TPS 5, AD09206, CB06803, ACK14001, TM10085, TM12007, PM12009 and EC725224 are under Efficient and responsive (ER) category which gives average yield at low level and high N use efficiency. The plant height, productive tillers, total grains, harvest index, panicle length and 1000 grain weights given verified results among the genotypes due to genetic characters. Among the N levels the plant height, panicle length, productive tillers per hill and total grains showed highest in 180 kg N ha-1. 1000 grain weight increased at low level of 50% of RDN (21.0) and decreased to 20.8 in N2 and N3 treatments which indicated higher doses of N. N harvest index were decreased with increasing level of N application from 0.70 (N0), 0.65(N1), 0.64 (N2) and 0.63 (N3).

Nitrogen Contribution by Groundnut (Arachis hypogaea L) Genotypes in the Northern Guinea Savanna of Nigeria

Most grain legumes irrespective of their ability to fix substantial amount of nitrogen to the soil, could impact negatively on the soil nitrogen balance, particularly if the fix nitrogen is exported from the field with harvested biomass (Shoot, root, grain/kernel). Thus, for agronomic purposes, it is important to quantify the potential amount of nitrogen from this source that will become available to the soil for subsequent crop uptake and/or ecosystem balance. The field trial was undertaken at the teaching and research field of the Institute for Agricultural Research (IAR) Samaru Zaria in the wet planting season of 2011 and 2012. The treatments consist of ten groundnut genotypes (SAMNUT 24, SAMNUT 22, ARRORSICGX-SM 00017/5/P15/P2, SAMNUT 10, ICIAR 7B, ARRORSICGX 000201/5/P4P10, SAMNUT 21, 6AT, SAMNUT 23 and SAMNUT 14), and two rates (0 and 30 kg N ha-1) of nitrogen (urea) fertilizer arrange in a split plot design. Nitrogen balance was estimated as the difference in nitrogen fix by the plant and nitrogen content of kernels/haulms. Results of the analysis of variance indicate that there was significant variation among the selected groundnut genotypes in their net contribution of nitrogen in both 2011 and 2012 at instances where both the groundnut kernel and haulms were exported from the field. Nitrogen contributions by the genotypes were not consistence in both years. In 2011, while SAMNUT 14 left the highest value of 9.79 kg N ha-1, ICIAR 7B returned the highest value in 2012. ICGX-SM 00017/5/P15/P2 (-16.55 kg N ha-1) and SAMNUT 22 (-56.07 kg N ha-1) contributed the least amount of nitrogen in 2011 and 2012 respectively when the kernel were removed from the field. On the other hand, 6AT was relatively stable in both years, and contributed close to 1 kg N ha-1. Even though negative nitrogen balances were reported at instances where the kernels were exported from the field, a more severe N depleting effect was observed when both haulms and kernels were removed from the field. Although, negative N balance was predominant at both rates (0 and 30 kg N ha-1) of N application, but the average nitrogen contribution was significantly higher (-1.10 kg N ha-1) with the application of starter nitrogen than the control (-13.23 kg N ha-1). In view of these findings, groundnut genotypes 6 AT, SAMNUT 14 and ICIAR 7B could be elite genotypes if building a resilience sustainable ecosystem is a priority due to their high biological nitrogen fixing abilities and nitrogen contributing potential.