Usually there is a high correlation between N content and chlorophyll in common bean leaves, because N is part of the chlorophyll molecule. Thus, a leaf nitrogen increase may reflect directly on the IFC values. This shows the potential for non- destructive indirect measurement of chlorophyll as a means to estimate the need for N by common bean plants. However, in this study we did not find a significant influence of N application rates or a linear correlation between leaf N content and IFC readings, nor between these values and bean grain yield. This fact is probably due to the history of this agricultural area under NTS (8-9 years), during which time there has been an increase in soil organic matter and nutrients, including N, as a result of straw accumulation and the mineral fertilizer application (possible residual effect, in a clay soil), can be adequately provided this nutrient for common bean, reducing the effect fertilization on the IFC values, because not every N absorbed is allocated for the chlorophyll production.
The study site had been previously cultivated in crop rotation under a no-till system with annual crops and semi-evergreens with corn in the off-season (Zea mays) (2004), soybeans (Glycine max) (2004/2005), sorghum (Sorghum bicolor) (2005), dwarf pigeon pea (Cajanus cajan) (2006), and U. brizantha „Marandu‟ (2007). The previous crop was composed of Urochloa species in the summer, the straw from which was subsequently utilized during common bean sowing.
The greatest limitation to the sustainability of no-till systems in Cerrado environments is the low quantity and rapid decomposition of straw left on the soil surface between fall and spring, due to water deficit and high temperatures. In the 2008/2009 growing season, in an area under center pivot irrigation in Selvíria, State of Mato Grosso do Sul, Brazil, this study evaluated the lignin/total N ratio of grass dry matter , and N, P and K deposition on the soil surface and decomposition of straw of Panicum maximum cv. Tanzânia, P. maximum cv. Mombaça, Brachiaria. brizantha cv. Marandu and B. ruziziensis, and the influence of N fertilization in winter/spring grown intercropped with maize, on a dystroferric Red Latosol (Oxisol). The experiment was arranged in a randomized block design in split- plots; the plots were represented by eight maize intercropping systems with grasses (sown together with maize or at the time of N side dressing). Subplots consisted of N rates (0, 200, 400 and 800 kg ha -1 year -1 ) sidedressed as urea (rates split in four
During the first experimental year, at the end of the GP, the ASIL were lower than one. This does not necessarily mean the leaves were deprecated by the animals, but that it was rather a consequence of the lower LLA and PLL, both in the total herbage and in the consumed forage, in addition to the possible difficulty in seizing it. The lack of significance of N levels on the variables LLA and ASIL provided similar ADG and ADGA in the first year (Table 2). In the second year, although no differences were observed (P> 0.10) in ADG, the N level of 40kg ha –1 provided a higher ADG (0.551kg day –1 ), which led to a higher ADGA (Table 2). Despite the lack of effects of the N levels on the animal performance, the ADG and ADGA are quite expressive, because the BW loss is common for animals in this period (Euclides et al., 2007; Silva et al., 2009). Even in pastures with a structure unfavorable to intake, the ADG of the animals in the dry period (Santos et al., 2009a) were positive. It highlights the importance of this strategy, which can be sufficient to provide a reduction of slaughter age.
In the three previous crop cycles, in the plots, the same proportions of straw were maintained on soil surface, whose quantities varied due to total straw yield. The uncrushed straw was distributed on soil surface in successive layers, containing all the straw mass for each treatment. The experimental plots presented the dimensions of 10 m of width x 15 m of length. A randomized complete block design was used, with five treatments and four replicates. Soil water storage variation was measured at two depths, in the layers of 0.0–0.3 and 0.3–0.6 m. Sugarcane was cultivated at a spacing of 1.4 m between rows, with 15 gems per linear meter.
Because it is a tropical country, the productive potential of pastures in Brazil is high, being also the least expensive and most efficient way of providing food in livestock production (DE ALENCAR et al., 2009; DIAS-FILHO, 2011;). Thus, understanding the aspects of water availability, soil fertility conditions, temperature and luminosity is fundamental for the application of rational and efficient management strategies (OLIVEIRA et al., 2011; SKONIESKI et al., 2011). Among other factors, nitrogen fertilization promotes increase in productivity and improve forage quality (FAGUNDES et al., 2012; PEREIRA et al., 2012, PREMAZZI et al., 2011) and when this practice is associated Irrigated can reduce the seasonality of production and the benefits are intensified (QUEIROZ et al., 2012). However, the productive capacity of pastures is also conditioned by climatic factors, mainly temperature and photoperiod (ALENCAR et al., 2009; NEWMAN et al., 2007).
Abstract – The majority of citrus trees in Brazil are grafted on ‘Rangpur lime’ (Citrus limonia Osb.) rootstock. Despite its good horticultural performance, search for disease tolerant rootstock varieties to improve yield and longevity of citrus groves has increased. The objective of this work was to evaluate yield efficiency of sweet oranges on different rootstocks fertilizedwith N, P, and potassium. Tree growth was affected by rootstock varieties; trees on ‘Swingle’ citrumelo [Poncirus trifoliata (L.) Raf. × C. paradisi Macf.] presented the smallest canopy (13.3 m 3 in the fifth year after tree planting) compared to those on ‘Rangpur lime’ and ‘Cleopatra’ mandarin
OM has large specific surface, negative net charge dependent on pH, ease of imbibition of water and soil solution containing metals and capacity to form organic chelates (Plaza et al., 2013). Cu can be complexed to OM in insoluble organic forms, being little available. The main bond of Cu in the OM is in the organic acids of higher molecular weight forming stable complexes of high energy (Pires & Mattiazzo, 2007; Ceretta et al., 2010). In Cu-deficient soils, the bonding force decreases with the increase of the applied amount, but increases with the higher degree of humification and with pH (Kumpiene et al., 2007; Muñoz et al., 2008).
Overseeding in general, except for T+126+89, caused no variations in productivity (VP) compared to the Tifton 85 alone (Table 5), corroborating the results reported by Moreira et al. (2006b) and Silva et al. (2012). The treatments T+MS and T+126 presented higher VP in the second grazing cycle in relation to the Tifton 85 alone and other treatments of overseeding, coinciding with the decrease in productivity of the pasture of Tifton 85 alone in this cycle (Table 2), certainly influenced by the lower temperature in June (Table 1).
2010/2011. This performance most likely resulted from the marked water deficit in the summer (Table 1). However, a significant negative linear response was observed with increased fertilisation in the spring and summer of 2011/2012, possibly due the effect of greater N availability, which increased the use of available carbohydrates in the production of cytoplasmic components rather than thickening the cell walls by the accumulation of polymeric substances (FAGERIA; CARVALHO, 2014). A reduction in the neutral detergent fibre values is important because these are the most limiting factors for forage intake according to Van Soest (1994), and values of cell wall components higher than 55-60 g kg -1 DM are negatively correlated with forage intake.
Another aspect to be considered in grain yield is the potential release of N by straw mineralization (Farinelli & Lemos, 2010; Costa et al., 2012a). In this sense, U. ruziziensis may have released a greater N amount and other nutrients in its composition to the soil relative to corn straw because of its smaller C/N ratio, allowing greater nutrient cycling. Perennial forage grasses have high root density, periodic renewal of the root system and even distribution of exudates into the soil (Cunha et al., 2011), improving soil biology and promoting biological fixation of atmospheric N 2 through rhizobia strains present in the soil (Silva et al., 2009). The use of these species in crop rotation, particularly Brachiaria, help to improve the soil structure, add organic matter, eliminate pathogens and supply N to the production system up to 45 kg ha -1 , because
Yields given by different genotypes are affected by many factors, but mostly by genotype, climatic conditions and applied growing practice. Therefore, the aim of this study was to establish productivity of many winter wheat genotypes in southern Serbia, through macro-trials. The results showed the difference of grain yield mean between the investigated seasons, and that difference amounted about 1300 kg/ha. The average yield was the highest in cultivars Toplica, Stamena, Evropa, NS- rana 5, and Renesansa. The lowest grain yield was given by cultivars Tina, Sara, Sreca, and Mina.
Besides being used in folk medicine for therapeutic purposes, plants are important sources of various pharmaceutical drugs. Although many of these compounds can be synthesized in the laboratory, the synthesis is complex, resulting in low yields and an unfeasible economic production. Among the various plant species, Catharanthus roseus G. L Don (periwinkle) contains more than 130 different terpenoid indole alkaloids (cyclic and nitrogen-containing compounds), several of which have important pharmaceutical uses, such as ajmalicine, found in roots and used as an antihypertensive (Almagro et al., 2015). Plants often produce alkaloids to defend themselves against adverse environmental conditions and external biological stimuli (Zeng et al., 2013).
soluble polymers marketed by Wirstchat Polímeros do Brasil. Each experimental plot had six rows, spaced 0.2 m, and six meters long. Four central rows were considered in these experiments and two guard rows were discarded. The cultivar Primavera CL was sown on 10 th November, 2009 at Santo Antônio de Goiás and on 15 th November, 2011 at Paraúna, after fertilizers (100 kg MAP + 100 kg KCl ha -1 ) application in the sowing furrow. Treatments were applied on soil surface at 20 days after plant emergence. Weed, pest and disease controls were made. Foliar sampling (MALAVOLTA et al., 1997), was made at Paraúna’s experiment in order to evaluate N content. The number of panicles/m 2 , number of grains/panicle, mass of 1000 grains and rice yield (with moisture corrected to 13%) were evaluated at harvest.
The two-way ANOVA analyses indicated that the rice grain yields were significantly affected by the year and fertilizer treatment (Table 2). The farmers’ practice plot (RN300) had an average rice grain yield of 8395 kg ha −1 , with an NUE of 31.35 %, over the two growing seasons from 2013 to 2014. Compared with RN300, reducing the N fertilizer rate by 20 % (RN240) slightly improved the grain yield and NUE to 8576 kg ha −1 and 34.58 %, respectively. Further N reduction, without additional agricultural managements, could decrease the rice yield by 8.15 % (RN180) and 15.18 % (RN120; Ta- ble 3). The response of rice yield to the synthetic N applica- tion rate in our study successfully fitted a quadratic model (Fig.2), as has been reported in previous studies (Xia and Yan, 2012; Cui et al., 2013a). Reducing N application reason- ably, therefore, is considered essential to reduce environmen- tal costs, without sacrificing grain yield (Chen et al., 2014). Our study showed that lowering the N input adopted by local farmer (300 kg N ha −1 ) by 20 % could still enhance the grain yield and NUE. However, a further reduction of N by 40 % (RN180) would largely impair the rice yield (Table 3).
Silva et al. (2001) applied increasing doses of sewage sludge in soil and, despite the fact that they were applied separately to mineral phosphorus sources, they found very similar results to those obtained in the present work. The results obtained by Chueiri et al. (2007) showed that the increasing doses of alkaline biosolid added to mineral phosphorus fertilization, despite the high initial soil P concentration, resulting in a linear increase in the extractable P (Mehlich-1). These authors attributed the fact to the high values of soil pH occasioned by the incubation of alkaline biosolid during 20 days which should have solubilized the nutrient and increased the values of extractable P. However, it must be considered that these results may be due to the extractant used which extracted both the available and the unavailable soil P (Novais & Smith, 1999). In this work there was no incubation but it seems the time spent during the bean plant growth was enough to provide the very similar results.
winter wheat (Triticum aestivum L.). Experiment was realised on the experimental bases of Slovak University of Agriculture in Nitra – Dolná Malanta. Locality of Dolná Malanta is in 175 – 185 m above sea level and belongs to warm climate zone. The studied soil was a Haplic Luvisol (loess parent material). In the experiment three main tillage systems for winter wheat were used: B1 = conventional soil cultivation (to 0.25 m); B2 = shallow soil cultivation (to 0.20 m); B3 = minimalization soil tillage (to 0.15 m). Within each treatment was used of NPK fertilization according to its content in soil + plough down of post harvest residues. Preceding crop was pea (Pisum sativum). Soil samples were taken in the two-weeks intervals, in each growing period was made 11 takings of soil samples. In the collected samples were determined contents of inorganic nitrogen forms (N-NO 3 - and N-NH 4 + ) in 1% solution of
justified. It is also worth mentioning the positive effect of nitrogen on gas exchanges, potentiating the photosynthetic rate of the forage plant (Pompeu et al., 2010; Lopes et al., 2011b). Among the components of total biomass, the green leaf blade is the most relevant fraction in the photosynthetic potential of the pastures, besides being the essential structural variable for grazing animal performance, since it is the fraction with better nutritional composition and greater acceptability by the animals.