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The suitable management of nitrogen (N) fertilization can increase barley grain yield, since it is the nutrient required in greater quantity. In this sense, the source and timing of nitrogen application are relevant factors. The objective was to evaluate the effects of N sources and splitting on the performance of barley. The experiment was carried out under a clayey Cambisol (550 g kg-1), in Curitibanos, Santa Catarina. Factorial randomized blocks were used: three mineral sources of N: urea (45% N); urea with urease inhibitor-NBPT (45% of N) and nitrate (30% of N), associated with two nitrogen splitting fertilization: i) split of the rate of N in two seasons: beginning of tillering and full tillering and ii) single application at full tillering. 100 kg ha-1 of N were applied. There was no interaction between the factors and there was no effect of treatments for plant height, ear length, grains per ear, ears per m? and mass of a thousand grains. Yield was influenced by the N source, where nitrate exceeded the yield from amidic sources by 16%. The splitting of N in two times did not present advantages over the single application. Urea with NBPT was not viable in relation to readily soluble forms of N, with the highest yield obtained with a nitric source. [ABSTRACT FROM AUTHOR]

Maize is highly demanding and responsive to nitrogen (N) fertilization, inserted in several production systems, with the recent highlight for integrated production systems. This study aimed to assess the effect of N rates on maize, as well as the economic aspect in an integrated production system. The experimental design was a randomized complete block design with four replicates. Four N rates in topdressing (0, 40, 80, and 120 kg ha-1) were assessed. Maize was cultivated under black oat and ryegrass mixed straw. Stem diameter, main ear insertion height, and ear parameters, except for the number of rows per ear, which increased linearly as a function of N rates, in turn, plant height responded quadratically until 81 kg N ha-1. Grain yield increased significantly as a function of N, indicating a residual effect of winter fertilization and high N use efficiency in the production system. The highest grain yield and profitability were obtained at the rate of 120 kg N ha-1. [ABSTRACT FROM AUTHOR]

Soil compaction periodic monitoring through soil penetration resistance (PR) has been a rapid, easy, andeconomic way to evaluate the different management systems on soil physical attributes effect. The aim was to evaluate thegrazing intensities and nitrogen fertilization effect in two winter/summer seasons (black oat/corn/black oat/soybean) on soil PRin an integrated crop-livestock system. The experimental design was in randomized blocks, in a factorial 2×3 [2 black oat pastureresidual heights (15 and 7 cm), under rotational grazing × 3 nitrogen rates applied to pasture (0, 75 and 150 kg N ha-1)], with 4repetitions. Soil PR was measured using an electronic penetrograph to an 80 cm depth. Soil samples were collected to determinegravimetric moisture. In the first year, 75 kg N ha-1 resulted in the highest depth compaction while intensive grazing (7 cm)resulted in the highest PR. In the second year, plots without N resulted in lower PR levels, mainly in the superficial layers. However, the rate of 150 kg N ha-1 presented greater compaction in the 15-20 cm layer after grazing. The high moisture levelsin depth reduced PR in all evaluated periods, highlighting the close relationship between both variables. General grazing heightsdid not affect PR, but the use of systems that increase residues production, as moderate grazing and nitrogen fertilization mightbe an alternative to mitigate the soil compaction in surface layers effects. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilization is essential for obtaining high garlic yields and satisfying commercial requirements for bulb diameter. However, excess nitrogen may favor the development of lateral shoots. This study aimed to examine the effect of different N application strategies on garlic yield and quality. The experiment was conducted in the field using garlic cv. Chonan and four N fertilization strategies (T1, N fertilizer applied at 15-day intervals; T2, N fertilizer applied before and after clove differentiation; T3, N fertilizer applied before clove differentiation; and T4, N fertilizer applied after clove differentiation). All treatments received the same N rate (210 kg ha-1). A single N application before clove differentiation (T3) favored lateral shoot growth, resulting in the highest incidence of this defect (11.66%). The other treatments did not differ in lateral shoot incidence. Four classes (3-6) of bulb diameter were observed, with treatments ranked in decreasing order as T2 > T1 > T3 > T4. There were no significant differences in garlic yield between single N application treatments (T3 and T4). However, garlic yield differed by 73% between T1 (13,329 kg ha-1) and T4 (7,679 kg ha-1), by 55.31% between T2 (11,927 kg ha-1) and T4, and by 36% between T1 and T3 (9,783 kg ha-1). These results indicate that two N fertilization strategies can be adopted in high-quality garlic production: fortnightly N fertilization or split N application before and after clove differentiation. A single N application is not recommended, regardless of application timing, as it promotes lateral shoot growth and reduces garlic quality and yield. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of off-season crops and fertilization with N mineral at soybean sowing on the nitrate and ammonium contents in the soil during the off-season and soybean development cycle. The experimental design was of randomized complete blocks, with five replications and in split plod scheme. Six off-season treatments were evaluated in the plots: fallow, maize with 0 or 80 kg of N ha1, wheat, Urochloa ruziziensis and Crotalaria spectabilis. In the subplots two levels of N were evaluated in the soybean sowing (0 and 30 kg N ha-1). From April 2016 to February 2017, 26 soil samples were collected in the 0.0-0.1 m layer, and the nitrate and ammonium contents in the samples were evaluated. During the off-season, the highest contents of nitrate were observed in maize fertilized with 80 kg de N ha-1, while ammonium contents varied less among off-season crops. The off-season crops did not influence the soil nitrate and ammonium content during the soybean cycle. In the vegetative phase of soybean, nitrate contents were higher when the soybean received nitrogen fertilization in relation to the absence of fertilization, but in the pod and grain formation there was no effect of the nitrogen fertilization on the contents of inorganic N. [ABSTRACT FROM AUTHOR]

• We assessed impacts of grazing and N rates on N 2 O and CH 4 emission in an integrated crop-livestock system (ICLs); • Intensive grazing and N fertilization in winter pasture increased annual soil N 2 O emission; • N fertilization and grazing in winter pasture increased N 2 O emissions in soybean in summer; • Moderate grazing did not increase soil N 2 O or CH 4 emissions compared to no grazing; • N fertilization in moderate grazing enhanced crops yields. Attending the global demands for primary resources without jeopardizing the environment's sustainability has become a challenge in recent decades. The adoption of conservationist systems, such as integrated crop-livestock systems (ICLs), has been widely discussed as a promising strategy. However, there is still scarce knowledge concerning pasture management, optimal fertilizer rates, and effects of livestock on soil processes, especially in the greenhouse gas emissions in subtropical climate regions. We aimed to assess soil nitrous oxide (N 2 O) and methane (CH 4) emissions, crop yield, and nitrogen use efficiency (NUE) in an ICLs under grazing intensities and nitrogen (N) fertilization rates. A field experiment was conducted during the winter and summer crop seasons. In winter, black oat (Avena strigosa Schreb.) pasture was subject to grazing intensities: ungrazed, moderately grazed, and intensively grazed by heifers; and fertilized with different N rates: 0, 75, and 150 kg N ha−1. In the summer, soybean (Glycine max (L.) Merr.) was grown over those winter treatments. Soil N 2 O and CH 4 emissions were measured by the static chamber method, and the fluxes and cumulative emissions were calculated. Simultaneously, we measured the crops' productivity and the NUE. Moderate grazing did not affect N 2 O and CH 4 emissions relative to ungrazed but reduced the NUE in black oat. Conversely, intensive grazing combined with 75 and 150 kg N ha−1 increased soil N 2 O emissions, mainly during the winter. Grazing and N application did not change soil CH 4 fluxes, characterized by CH 4 uptake most of the time. Nitrogen fertilization, regardless of the rate, increased soil N 2 O emissions, but this fertilization and its residual effects were crucial to achieving high black oat and soybean yields. Results indicate that black oat can reach high yields in ICLs under moderate grazing and N fertilization rates of 75 and 150 kg N ha−1, with lower N 2 O emissions than under intensive grazing. Our study provided a quantitative assessment of an ICLs production efficiency in the Brazilian subtropics, regarding crop yield, NUE, and the emissions of important greenhouse gases to the atmosphere. The findings suggest that the use of moderate grazing with N fertilization on black oats may determine the trade-offs between food production and the harmful effects induced by land use. [ABSTRACT FROM AUTHOR]

Sowing density in the soybean crop promotes several morphophysiological changes in the plants, which can alter plant growth and grain yield. The objective of this study was to evaluate the effect of soybean plant densities on the leaf area index (LAI) and Soil Plant Analysis Development (SPAD) index during the soybean crop development cycle and correlating these data with grain yield. The experiment was conducted in the experimental area of Embrapa Soja, Londrina, ParanáState, Brazil, under a randomized complete block design, with five replications. The densities of 120, 230, 340 and 380 thousand viable plants ha-1 were evaluated in row spacing of 0.45 m using the BRS 359 RR cultivar, which has indeterminate growth type and compact architecture. The increased plant density promotes an increment in LAI from the V4 stage to R3, however, after this stage, LAI is similar among densities. Plant density did not change the SPAD index before R5.4. During the vegetative growth there is no correlation between LAI and SPAD and grain yield, but in the grain filling period there are positive correlations between these variables. [ABSTRACT FROM AUTHOR]

The dual-purpose wheat is intended to forage production and subsequently grain production. The objective was to evaluate BRS Tarumã and BRS Umbu cultivars for forage mass production and grain yield under nitrogen (N) rates. The experiment was conducted in 2014, in experimental randomized blocks with split plot design, using two cultivars of dual-purpose wheat (BRS Umbu and BRS Tarumã) and four nitrogen rates (0, 30, 60, and 120 kg N ha-1), adding a control (0 kg N ha-1),four replicates, the application was split. There was no interaction between cultivars and nitrogen rates. BRS Umbu cultivar was distinguished by plant height, ear length, number of grains per spike, and grain yield. In the dry mass production, the cultivars did not differ. There was linear and positive response with increasing N rates for all yield components and dry mass of forage. It was concluded that the N rate application up to 120 kg ha-1 provided the highest yield in all analyzed parameters, that in relation to yield components, as well as grain yield to BRS Umbu, stands out in relation to BRS Tarumã. [ABSTRACT FROM AUTHOR]