60 research outputs found
Partition and macronutrients accumulation in pineapple under nitrogen doses and plant density
Studies related to the absorption and exportation capacity of macronutrients by irrigated pineapple are essential for the definition of adequate doses and fertilization management. The objective of this study was to evaluate the accumulation of biomass and macronutrients in the compartments (leaves, shoot, root, seedlings/slip, crown/top, and fruit) of ‘Vitória’ pineapple irrigated in the semiarid region after the use of nitrogen doses and population densities. The treatments, arranged in randomized blocks with three replicates, arranged in a 5x4 factorial scheme, consisted of five nitrogen doses (0, 5, 10, 15 and 20 g per plant) and four population densities (51,282, 76,923, 90,909, and 126,984 plants ha-1). The accumulation of biomass and macronutrients in the pineapple compartments was evaluated at the end of the growing cycle. The increase of N doses combined with the increase of the plant population promoted a linear increase in the accumulation of biomass and macronutrients by the pineapple plants. The leaves presented greater accumulation of macronutrients, followed by the seedlings, shoot, fruit, crown, and roots. The pineapple presented the following decreasing order of macronutrient absorption: K> N> Ca> P> Mg>S. At the dose of 20 g per plant of N and population of 126,984 plants ha-1 were exported from the area by fruits, 1,311 (12%), 150 (9%), 144 (11%), 52 (11%), 46 (12%) and 36 (12%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively; and by the shoots, 2,426 (22%), 480 (29%), 147 (11%), 101 (21%), 67 (18%), and 45 (15%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively.Studies related to the absorption and exportation capacity of macronutrients by irrigated pineapple are essential for the definition of adequate doses and fertilization management. The objective of this study was to evaluate the accumulation of biomass and macronutrients in the compartments (leaves, shoot, root, seedlings/slip, crown/top, and fruit) of ‘Vitória’ pineapple irrigated in the semiarid region after the use of nitrogen doses and population densities. The treatments, arranged in randomized blocks with three replicates, arranged in a 5x4 factorial scheme, consisted of five nitrogen doses (0, 5, 10, 15 and 20 g per plant) and four population densities (51,282, 76,923, 90,909, and 126,984 plants ha-1). The accumulation of biomass and macronutrients in the pineapple compartments was evaluated at the end of the growing cycle. The increase of N doses combined with the increase of the plant population promoted a linear increase in the accumulation of biomass and macronutrients by the pineapple plants. The leaves presented greater accumulation of macronutrients, followed by the seedlings, shoot, fruit, crown, and roots. The pineapple presented the following decreasing order of macronutrient absorption: K> N> Ca> P> Mg>S. At the dose of 20 g per plant of N and population of 126,984 plants ha-1 were exported from the area by fruits, 1,311 (12%), 150 (9%), 144 (11%), 52 (11%), 46 (12%) and 36 (12%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively; and by the shoots, 2,426 (22%), 480 (29%), 147 (11%), 101 (21%), 67 (18%), and 45 (15%) kg ha-1 of K, N, Ca, P, Mg, and S, respectively
Estoques de carbono e nitrogênio em frações da matéria orgânica de solos cultivados com eucalipto nos sistemas convencional e fertirrigado
O presente estudo teve o objetivo de avaliar os estoques de C e N nas frações lábeis e estáveis da MOS e da biomassa microbiana em resposta ao cultivo florestal com o uso de fertirrigação quando comparado ao cultivo convencional. Para tanto, duas áreas cultivadas com eucalipto num mesmo solo (Argissolo Amarelo), mas com manejos fertirrigado e convencional foram amostradas nas camadas de 0-10, 10-20, 20-40, 40-60 e 60-100cm de profundidade na linha e entrelinha de cultivo. A amostragem da entrelinha foi justificada pelo enleiramento e enterro de resíduos vegetais provenientes da colheita do cultivo anterior na entrelinha do cultivo atual. No final do ciclo de cultivo do eucalipto (sete anos), a deposição de serapilheira e os estoques de C e N na maioria das frações lábeis e estáveis da MOS foram maiores no sistema fertirrigado, com incremento de 50,34t ha -1 de C total (COT) e 5,62t ha -1 de N total (NT), na camada de 0- 100cm de profundidade, em comparação àqueles do sistema convencional. O solo da entrelinha de plantio, principalmente no sistema fertirrigado, apresentou maior estoque de C e N total e C nas frações das substâncias húmicas e na fração leve da MOS que no solo da linha de plantio, possivelmente em virtude da maior deposição e incorporação de resíduos vegetais do ciclo anterior na entrelinha do cultivo atual. A intensificação do manejo de florestas comerciais de eucalipto com o uso de fertirrigação possibilita aumentar a deposição de resíduos vegetais e sequestrar mais C e N, tanto em frações estáveis, quanto em frações mais lábeis da MOS, especialmente nas camadas de solo de até 40cm de profundidade.The objective of this study was to evaluate the C and N stocks in fractions of labile and more stable SOM fractions in response to intensification of forest cultivation through fertirrigation when compared to conventional stands. To that end, two areas planted with eucalyptus in the same (Ultisol), but with different managements (fertilized and irrigated and conventional system) were sampled in the 0-10, 10-20, 20-40, 40-60 and 60-100cm deep soil layers in line and interrow of the cultivation. The sampling interrow soil was justified by the ridged and burial of plant residues from previous crop cultivation in-between the substrate. At seven years old, eucalypt under fertirrigation increased the litterfall and the C and N stocks in the most labile and stable SOM fractions, leading to greater stocks of C and N in the 0-100 cm deep soil layer. The increments due to fertirrigation observed for total C was 50.34 and for the labile fraction was 5.62t ha -1 . The eucalypt interrow soil, especially in the fertirrigated treatment, presented larger stocks of total C and N and also larger C stocks in humic substances and light fraction of SOM possibly due to greater deposition and incorporation of vegetable residues from the previous cycle in the interrow current cultivation. The intensification of water and nutrients usage in short-rotation eucalypt stands is an alternative to increase the deposition of vegetable residues and C sequestration in more stable and labile SOM fractions, especially in the 0-40cm soil layer
BIOMARCADORES DERIVADOS DE PLANTA E DE MICRORGANISMOS EM SOLOS DE TABULEIROS COSTEIROS CULTIVADOS COM EUCALIPTO E AC\uc1CIA
Changes in the management systems for the cultivation of different
forest stands and the use of species rotation can lead to alterations
in the quality of soil organic matter (SOM) and plant residue
deposition. This study evaluated the stage of decomposition and the
contribution of plant and microbial origin for SOM through biomarkers,
such as lignin-derived phenols, carbohydrates and amino sugars in
continuous short rotation eucalypt ( Eucalyptus urophylla x
Eucalyptus grandis hybrid) (seven years) compared to a rotation
system including acacia ( Acacia mangium Willd.) after
short-rotation eucalypt; and long-rotation eucalypt (24 years). A
native vegetation (Atlantic Forest) was used as a reference for the
original site condition representative for the northern coast of
Esp\uedrito Santo state. To do so, we estimated the content of total
organic C (TOC), total N (TN) and the contents of lignin-derived
phenols (VSC), the carbohydrates and the amino sugars derived from soil
microorganisms, and acids/aldehyde ratio of groups vanilil
((Ac/Al)vanilil) and syringyl ((Ac/Al)syringyl) of the lignin,
hexoses/pentoses (H/P) ratio of carbohydrates, besides
glucosamine/muramic acid (Gluc/Ac. Mur) and glucosamine/galactosamine
(Gluc/Gal) ratios for soil and litter samples. The results indicated
that litter of the continuous short-rotation eucalypt has greater dry
mass, lignin (VSC) and carbohydrates contents, C/N and VSC/N ratios; a
similar proportion of coarse litter to fine litter and C content, but a
lower N content in comparison to the species rotation system that
includes the leguminous acacia. In the soil, acacia cultivation
increases C, N and carbohydrates content, widened the acid/aldehyde
ratio of vanilil groups of lignin and the glucosamine/muramic acid
ratio of amino sugars derived from microbial activity. The longer
rotation of eucalypt (24 years) increased C content and decreased the
VSC/N ratio in SOM compared to the continuous short-rotation eucalypt,
but still having C and N content lower than in soil of acacia and
native forest. The smallest Ac/Al ratio of lignin-derived phenols in
soils cultivated with eucalypt (in long and short-rotation) indicates
that the SOM is in less advanced stage of decomposition (humification)
than in the soil cultivated with acacia, and that under native forest.
In soils under acacia, followed by that of short-rotation eucalypt, the
higher glucosamine/muramic acid ratio suggested a greater contribution
of fungi in SOM cycling, whereas in the native forest and long-rotation
eucalypt there is greater abundance of bacteria-derived compounds.
Overall, the results indicate that there was a recovery in the quality
of the soils cultivated with eucalypt for a longer rotation and also
with acacia in relation to the continuous short-rotation eucalypt.Altera\ue7\uf5es no sistema de manejo pelo cultivo de diferentes
povoamentos florestais e a utiliza\ue7\ue3o de rota\ue7\ue3o de
culturas podem levar a altera\ue7\uf5es na qualidade da
mat\ue9ria org\ue2nica do solo (MOS) e deposi\ue7\ue3o de
res\uedduos vegetais. O presente estudo avaliou o est\ue1dio de
decomposi\ue7\ue3o e a contribui\ue7\ue3o de compostos de
origem vegetal e microbiana para a MOS por meio de biomarcadores, tais
como: fen\uf3is derivados de lignina, carboidratos e
aminoa\ue7\ufacares em monocultivos do Eucalyptus urograndis (clone
do Eucalyptus urophylla S. T. Blake x Eucalyptus grandis W. Hill ex
Spreng) de ciclo curto (sete anos), sistemas de cultivo de
rota\ue7\ue3o de ac\ue1cia ( Acacia mangium Willd.) ap\uf3s
monocultivo de eucalipto, monocultivo de eucalipto de ciclo longo (24
anos) e mata nativa (Mata Atl\ue2ntica) como condi\ue7\ue3o
original de solo do litoral Norte do Esp\uedrito do Santo. Para
tanto, foram estimados nas amostras de solo e serapilheira os teores de
C org\ue2nico total (COT), N total (NT), teores de fen\uf3is
derivados de lignina (VSC), carboidratos e aminoa\ue7\ufacares
derivados da atividade microbiana no solo e, as rela\ue7\uf5es
\ue1cidos e alde\ueddos dos grupamentos vanilil ((Ac/Al)Vanilil) e
siringil ((Ac/Al)Siringil) da lignina, rela\ue7\ue3o
hexoses/pentoses (H/P) dos carboidratos e, rela\ue7\uf5es
glucosamina/\ue1cido mur\ue2mico (Gluc/Mur.) e
glucosamina/galactosamina (Gluc/Gal) dos aminoa\ue7\ufacares. Os
resultados indicaram que na serapilheira do monocultivo de eucalipto de
ciclo curto houve maior deposi\ue7\ue3o da mat\ue9ria seca, teor
de lignina (VSC) e carboidratos, rela\ue7\ue3o C/N e VSC/N;
Semelhante propor\ue7\ue3o de res\uedduos grossos, res\uedduos
finos e teor de C e, menor teor de N, comparado \ue0quela sob
rota\ue7\ue3o de ac\ue1cia. No solo, o cultivo de ac\ue1cia
aumentou os teores de C, N e carboidratos, aumentou a rela\ue7\ue3o
\ue1cido/alde\ueddo do grupamento vanilil da lignina e a
rela\ue7\ue3o glucosamina/\ue1cido mur\ue2mico dos
aminoa\ue7\ufacares derivados da atividade microbiana. O aumento do
tempo de cultivo do eucalipto (24 anos) incrementou o teor de C e
reduziu a rela\ue7\ue3o VSC/N na MOS em compara\ue7\ue3o ao
monocultivo de eucalipto de ciclo curto, e apresentou teor de C e N
inferiores \ue0queles observados no solo de ac\ue1cia e mata
nativa. A menor rela\ue7\ue3o \ue1cidos/ alde\ueddos (Ac/Al)
dos fen\uf3is derivados de lignina no solo cultivado com eucalipto
(de curto e longo ciclo) indica que a MOS encontra-se em est\ue1dio
menos avan\ue7ado de decomposi\ue7\ue3o do que no solo cultivado
com ac\ue1cia, e naquele de mata nativa. Nos solos de ac\ue1cia,
seguido por aquele de eucalipto, a maior rela\ue7\ue3o
glucosamina/\ue1cido mur\ue2mico sugere maior
participa\ue7\ue3o de fungos na comunidade microbiana, enquanto nas
\ue1reas de mata nativa e eucalipto de ciclo longo h\ue1 mais
abund\ue2ncia de compostos derivados de bact\ue9rias. Neste
sentido, observou-se a recupera\ue7\ue3o na qualidade do solo
cultivado com eucalipto de ciclo longo e rotacionado com ac\ue1cia em
rela\ue7\ue3o ao monocultivo de eucalipto de ciclo curto
Chickpea production in response to fertilization with zinc and doses of phosphorus
Chickpea cultivation in Brazil has not yet been consolidated, and studies aiming at the adequate nutritional management for this crop are necessary. This work aimed to evaluate the production of chickpea plants (cultivar BRS Aleppo) subjected to fertilization with zinc and P doses. The experimental was completely randomized, with four replications, in a 3 x 5 factorial scheme, corresponding to three fertilization treatments with Zn (without Zn addition; 50% of Zn applied at sowing, via soil + 50% applied at flowering, via leaves; and 100% applied at sowing, via soil) and five doses of phosphorus (0, 60, 120, 180, and 240 kg ha-1 of P2O5). The 100-grain mass (M100), pod mass (MV), number of pods (NV), number of grains (NG), total grain mass (MGT), yield (PROD), dry matter of the shoot part (MSPA) and plant residues (MSRV), and agronomic efficiency (EA) were characterized. There was an isolated effect of the P doses on the M100, MGT, PROD, MSPA, and MSRV characteristics. The application of 240 kg ha-1 resulted in an increase in the production components and a maximum yield of 3,018 kg ha-1, indicating the need to adopt higher doses of P2O5 to increase chickpea production in tropical soils. However, the highest agronomic efficiency was obtained after the application of 60 kg ha-1 of P2O5, along with Zn at sowing.Chickpea cultivation in Brazil has not yet been consolidated, and studies aiming at the adequate nutritional management for this crop are necessary. This work aimed to evaluate the production of chickpea plants (cultivar BRS Aleppo) subjected to fertilization with zinc and P doses. The experimental was completely randomized, with four replications, in a 3 x 5 factorial scheme, corresponding to three fertilization treatments with Zn (without Zn addition; 50% of Zn applied at sowing, via soil + 50% applied at flowering, via leaves; and 100% applied at sowing, via soil) and five doses of phosphorus (0, 60, 120, 180, and 240 kg ha-1 of P2O5). The 100-grain mass (M100), pod mass (MV), number of pods (NV), number of grains (NG), total grain mass (MGT), yield (PROD), dry matter of the shoot part (MSPA) and plant residues (MSRV), and agronomic efficiency (EA) were characterized. There was an isolated effect of the P doses on the M100, MGT, PROD, MSPA, and MSRV characteristics. The application of 240 kg ha-1 resulted in an increase in the production components and a maximum yield of 3,018 kg ha-1, indicating the need to adopt higher doses of P2O5 to increase chickpea production in tropical soils. However, the highest agronomic efficiency was obtained after the application of 60 kg ha-1 of P2O5, along with Zn at sowing
Are biomass partitioning and nutrient accumulation in industrial tomato influenced by NPK fertilization?
This study aimed to evaluate the uptake, accumulation, and partitioning of nitrogen (N), phosphorus (P), and potassium (K) in the tomato crop fertilized with doses of NPK. The main plots consisted of three doses of N: 90, 135, and 180 kg ha-1, P: 270, 405, and 540 kg ha-1, and K: 225, 337, and 450 kg ha-1 (equivalent to 50, 75, and 100 % of the fertilization recommendation for industrial tomato), while the subplots consisted of the evaluation periods: 20, 40, 60, 80, and 100 days after transplanting (DAT). The dry matter and the accumulation of N, P, and K were characterized in the different plant components (leaves, stems, fruits, and total). The order of nutrient uptake for the hybrid BRS Sena was defined as K> N> P. The dose corresponding to 50 % NPK resulted in the maximum accumulation of total dry matter of 400 g per plant at 64 DAT and the total accumulation of 10, 1.14, and 14.51 g per plant of N, P, and K, respectively. The intermediate dose of NPK resulted in the maximum accumulation of total dry matter of 468 g and accumulations of 14, 1.6, and 19 g per plant of N, P, and K. At 100 % of the NPK recommendation, there was 514 g per plant of total dry matter, with maximum accumulations of 15, 1.6, and 18 g per plant of N, P, and K. The maximum accumulation rate of N, P, and K occurs at 60, 64, and 70 DAT for the fertilization recommendations corresponding to 50, 75, and 100 % NPK, respectively.Objetivou-se avaliar a absorção, acúmulo e partição de nitrogênio (N), fósforo (P) e potássio (K) pelo tomate rasteiro irrigado com doses de NPK. O delineamento experimental foi blocos ao acaso, com quatro repetições. As parcelas principais foram constituídas de três doses de N: 90, 135 e 180 kg ha-1, P: 270, 405 e 540 kg ha-1 e K: 225, 337 e 450 kg ha-1 (equivalentes a 50, 75 e 100% da recomendação de adubação para o tomateiro industrial) e nas subparcelas foram amostradas plantas nas épocas: 20, 40, 60, 80 e 100 dias após o transplantio (DAT). Caracterizou-se a matéria seca e acúmulo de N, P e K, nos componentes da planta (folha, haste, frutos e total). A ordem de absorção de nutrientes para o BRS Sena foi K>N>P. Na dose 50% de NPK houve máximo acúmulo de 400 g por planta de matéria seca total aos 64 DAT, e acúmulo total de 10; 1,14 e 14,51 g por planta de N, P e K, respectivamente. Na dose intermediária da recomendação de adubação NPK com produção 468 g por planta de matéria seca total houve acúmulos de 14; 1,6 e 19 g por planta de N, P e K. Em 100% da recomendação de adubação NPK, houve 514 g por planta de matéria seca total com máximos acúmulos de 15; 1,6 e 18 g por planta de N, P e K. A taxa de máximo acúmulo de N, P e K ocorre aos 60, 64 e 70 DAT para as recomendações de adubação 50, 75 e 100% NPK, respectivamente. A exportação dos macronutrientes seguiu a ordem decrescente K>N>P, para todas as recomendações de adubação NPK
ABUNDÂNCIA NATURAL DE 15N E FORMAS DE NITROGÊNIO EM ARGISSOLO CULTIVADO COM EUCALIPTO E ACÁCIA
http://dx.doi.org/10.5902/1980509821121The nutrients nitrogen and one of the most demanded by plant species, and its presence in soil under organic or mineral forms available to plants is linked to quality and quatity of plant residues added to the soil. The study aimed to evaluate the influence of cultivation of eucalyptus and acacia in the composition of organic and inorganic N forms and the natural abundance of 15N in an Ultisol. For this, we collected soil and litter samples in continuous short-rotation eucalypt (Eucalyptus urophylla x Eucalyptus grandis hybrid) (seven years) compared to a rotation system including acacia (Acacia mangium Willd.) after short-rotation eucalypt; and long-rotation eucalypt (24 years). A native vegetation (Atlantic Forest) was used as a reference for the original site condition representative for the northern coast of Espírito Santo state. To do so, we evaluated the content of total organic C, total N, N-NH4+, N-NO3-, C/N ratio, fractionation of organic N and 15N natural abundance in soil and litter. Among the forms of organic-N hydrolyzed, the N-amino was the fraction with the highest contribution of organic N (39%), followed by the fraction of N-unidentified (27%), the fraction of N-amide (18%) and N-hexosamine (15%). The acacia plantation presented smaller natural abundance of 15N and higher levels of total N and soil organic C, and increased organic forms of N-hydrolyzed, when compared to the eucalyptus short-rotation soil. This indicates the increase of labile N-organic forms in the soil for the plants and reduction of humification of soil organic matter (SOM) of acacia. Thus, the crops rotation with acacia after eucalyptus contributed to the increase of organic forms in the soil, important for the nutrition of plants, because they are potential sources of nutrients to the plants in a short-time period.The nutrients nitrogen and one of the most demanded by plant species, and its presence in soil under organic or mineral forms available to plants is linked to quality and quatity of plant residues added to the soil. The study aimed to evaluate the influence of cultivation of eucalyptus and acacia in the composition of organic and inorganic N forms and the natural abundance of 15N in an Ultisol. For this, we collected soil and litter samples in continuous short-rotation eucalypt (Eucalyptus urophylla x Eucalyptus grandis hybrid) (seven years) compared to a rotation system including acacia (Acacia mangium Willd.) after short-rotation eucalypt; and long-rotation eucalypt (24 years). A native vegetation (Atlantic Forest) was used as a reference for the original site condition representative for the northern coast of Espírito Santo state. To do so, we evaluated the content of total organic C, total N, N-NH4+, N-NO3-, C/N ratio, fractionation of organic N and 15N natural abundance in soil and litter. Among the forms of organic-N hydrolyzed, the N-amino was the fraction with the highest contribution of organic N (39%), followed by the fraction of N-unidentified (27%), the fraction of N-amide (18%) and N-hexosamine (15%). The acacia plantation presented smaller natural abundance of 15N and higher levels of total N and soil organic C, and increased organic forms of N-hydrolyzed, when compared to the eucalyptus short-rotation soil. This indicates the increase of labile N-organic forms in the soil for the plants and reduction of humification of soil organic matter (SOM) of acacia. Thus, the crops rotation with acacia after eucalyptus contributed to the increase of organic forms in the soil, important for the nutrition of plants, because they are potential sources of nutrients to the plants in a short-time period.http://dx.doi.org/10.5902/1980509821121O nitrogênio e um dos nutrientes mais demandados pelas espécies vegetais, sua presença no solo, sob formas orgânicas ou minerais disponíveis para as plantas, está vinculada à qualidade e quantidade dos resíduos vegetais aportados ao solo. O estudo teve o objetivo de avaliar a influência do cultivo do eucalipto e da acácia na composição das formas orgânicas e inorgânicas de N e, na abundância natural de 15N em um Argissolo Amarelo. Para isso, foram coletadas amostras de solo e serapilheira em monocultivos do Eucalyptus urograndis (clone do Eucalyptus urophylla S. T. Blake x Eucalyptus grandis W. Hill ex Spreng) de ciclo curto (sete anos), sistemas de cultivo de rotação de acácia (Acacia mangium Willd.) após monocultivo de eucalipto, monocultivo de eucalipto de ciclo longo (24 anos) e mata nativa (Mata Atlântica) como condição original de solo do litoral Norte do Espírito do Santo. Foram avaliados os teores de C orgânico total, N total, N-NH4+, N-NO3-, relação C/N, fracionamento do N orgânico e abundância natural de 15N no solo e serapilheira. Das formas de N-orgânico hidrolisado, o N- amino foi a fração que apresentou maior contribuição (39%), seguida pela fração de N- não identificado (27%), da fração N-amida (18%) e N-hexosamina (15%). O povoamento de acácia promoveu menor abundância natural de 15N e maiores teores de N total e C orgânico no solo e aumentou as formas orgânicas de N-hidrolisado, quando comparado àqueles de eucalipto de ciclo curto. Isto indica o aumento de formas lábeis de N orgânico no solo para as plantas e redução da humificação da matéria orgânica do solo (MOS) de acácia. Neste sentido, a rotação de cultivos florestais com acácia após eucalipto de ciclo curto contribuiu para o aumento de formas orgânicas no solo, importantes para a nutrição de plantas, por serem potenciais fontes de nutrientes às plantas em curto período de tempo
CARBON AND NITROGEN STOCKS IN THE ALFISOL SUBMITTED TO THE Eucalyptus urograndis MONOCULTURE AND Acacia mangium ROTATION
A busca de sistemas sustent\ue1veis de manejo do solo tem levado
pesquisadores a desenvolverem novas t\ue9cnicas de cultivo. Dentre
elas, destacam-se no Brasil estudos realizados com esp\ue9cies
florestais capazes de fixar N2 atmosf\ue9rico e aumentar o estoque de
C e N em fra\ue7\uf5es l\ue1beis e est\ue1veis da mat\ue9ria
org\ue2nica do solo (MOS). O presente estudo teve por objetivo
avaliar as altera\ue7\uf5es nos estoques de C e N em
fra\ue7\uf5es das subst\ue2ncias h\ufamicas, da
fra\ue7\ue3o leve da MOS e da mat\ue9ria microbiana em solos
cultivados com Eucalyptus urograndis em rota\ue7\ue3o curta,
eucalipto em rota\ue7\ue3o longa e povoamentos de Acacia mangium
que sucederam plantios de eucalipto em rota\ue7\ue3o curta, tendo
como refer\ueancia o solo de floresta nativa (Mata Atl\ue2ntica)
adjacente. Foram quantificados os estoques de C org\ue2nico total e N
total (COT e NT), nas fra\ue7\uf5es das subst\ue2ncias
h\ufamicas (fra\ue7\ue3o \ue1cido f\ufalvico-AF,
fra\ue7\ue3o \ue1cido h\ufamico-AH e fra\ue7\ue3o
humina-H), C e N da fra\ue7\ue3o leve da MOS (C-MOL e N-MOL) e
estoque de C e N da mat\ue9ria microbiana (C-BM e N-BM). Os
resultados indicaram que o cultivo do eucalipto em rota\ue7\ue3o
curta apresentou menores estoques de COT e NT, nas fra\ue7\uf5es
das subst\ue2ncias h\ufamicas e, de N na mat\ue9ria microbiana em
compara\ue7\ue3o ao solo sob rota\ue7\ue3o com Acacia mangium.
O cultivo de Acacia mangium e o aumento do tempo da rota\ue7\ue3o
do eucalipto incrementaram os estoques de C e N da maioria das
fra\ue7\uf5es l\ue1beis (C-MOL, N-MOL e C-BM) e est\ue1veis (C
e N nas subst\ue2ncias h\ufamicas), indicando tend\ueancia de
recupera\ue7\ue3o dos seus estoques para valores pr\uf3ximos
daqueles originais (mata nativa), sendo superiores aos estoques obtidos
na \ue1rea de eucalipto em rota\ue7\ue3o curta.The pursuit of sustainable systems of soil management has led
researchers to develop new techniques of cultivation. Among them,
studies with forest species able to fix atmospheric N2 and increase C
and N stocks in labile and stable soil organic matter (SOM) stand out
in Brazil. The study aimed to evaluate changes in stocks of C and N in
fractions of humic substances, light fraction of SOM and microbial
biomass in soils of short-rotation Eucalyptus \u201curograndis\u201d,
long rotation plantations and stands of Acacia mangium which
succeeded short rotation eucalyptus monoculture, in comparison to the
soil of native forest (Atlantic Forest). It was obtained the total
organic carbon (TOC) and total nitrogen (TN) stocks, C and N stocks in
the fractions of humic substances (fulvic acid fraction-AF, humic acid
fraction-HA and humin fraction-H), C and N in light fraction of SOM
(C-LOM and N-LOM) and C and N microbial biomass (CMB and N-MB). The
results indicated that the short rotation eucalyptus cultivation
reduced total organic carbon stocks, total nitrogen, C and N in the
humic substances, and N storage in the microbial biomass compared to
Acacia mangium soil. The cultivation of Acacia mangium and the increase
of the eucalyptus rotation time increased stocks of C and N of the
labile (C-LOM, N-LOM and C-MB) and stable fractions (C and N in humic
substances) indicating a significant recovery of their stocks to levels
approaching those original (native), and higher than stocks obtained in
the soil of short rotation eucalypt
THE 15N NATURAL ABUNDANCE AND NITROGEN FORMS IN ULTISOL CULTIVATED WITH EUCALYPTUS AND ACACIA
O nitrog\ueanio e um dos nutrientes mais demandados pelas
esp\ue9cies vegetais, sua presen\ue7a no solo, sob formas
org\ue2nicas ou minerais dispon\uedveis para as plantas, est\ue1
vinculada \ue0 qualidade e quantidade dos res\uedduos vegetais
aportados ao solo. O estudo teve o objetivo de avaliar a
influ\ueancia do cultivo do eucalipto e da ac\ue1cia na
composi\ue7\ue3o das formas org\ue2nicas e inorg\ue2nicas de N
e, na abund\ue2ncia natural de 15N em um Argissolo Amarelo. Para
isso, foram coletadas amostras de solo e serapilheira em monocultivos
do Eucalyptus urograndis (clone do Eucalyptus urophylla S. T. Blake
x Eucalyptus grandis W. Hill ex Spreng) de ciclo curto (sete anos),
sistemas de cultivo de rota\ue7\ue3o com ac\ue1cia ( Acacia
mangium Willd.) ap\uf3s monocultivo de eucalipto, monocultivo de
eucalipto de ciclo longo (24 anos) e mata nativa (Mata Atl\ue2ntica)
como condi\ue7\ue3o original de solo do litoral Norte do
Esp\uedrito do Santo. Foram avaliados os teores de C org\ue2nico
total, N total, N-NH4+, N-NO3-, rela\ue7\ue3o C/N, fracionamento do
N org\ue2nico e abund\ue2ncia natural de 15N no solo e
serapilheira. Das formas de N-org\ue2nico hidrolisado, o N-amino foi
a fra\ue7\ue3o que apresentou maior contribui\ue7\ue3o (39%),
seguida pela fra\ue7\ue3o de N-n\ue3o identificado (27%), da
fra\ue7\ue3o N-amida (18%) e N-hexosamina (15%). O povoamento de
ac\ue1cia promoveu menor abund\ue2ncia natural de 15N e maiores
teores de N total e C org\ue2nico no solo e aumentou as formas
org\ue2nicas de N-hidrolisado, quando comparado \ue0queles de
eucalipto de ciclo curto. Isso indica o aumento de formas l\ue1beis
de N org\ue2nico no solo para as plantas e redu\ue7\ue3o da
humifica\ue7\ue3o da mat\ue9ria org\ue2nica do solo (MOS) de
ac\ue1cia. Nesse sentido, a rota\ue7\ue3o de cultivos florestais
com ac\ue1cia ap\uf3s eucalipto de ciclo curto contribuiu para o
aumento de formas org\ue2nicas no solo, importantes para a
nutri\ue7\ue3o de plantas, por serem potenciais fontes de
nutrientes \ue0s plantas em curto per\uedodo de tempo.The nutrients nitrogen and one of the most demanded by plant species,
and its presence in soil under organic or mineral forms available to
plants is linked to quality and quatity of plant residues added to the
soil. The study aimed to evaluate the influence of cultivation of
eucalyptus and acacia in the composition of organic and inorganic N
forms and the natural abundance of 15N in an Ultisol. For this, we
collected soil and litter samples in continuous short-rotation eucalypt
( Eucalyptus urophylla x Eucalyptus grandis hybrid) (seven years)
compared to a rotation system including acacia ( Acacia mangium
Willd.) after short-rotation eucalypt; and long-rotation eucalypt (24
years). A native vegetation (Atlantic Forest) was used as a reference
for the original site condition representative for the northern coast
of Esp\uedrito Santo state. To do so, we evaluated the content of
total organic C, total N, N-NH4+, N-NO3-, C/N ratio, fractionation of
organic N and 15N natural abundance in soil and litter. Among the forms
of organic-N hydrolyzed, the N-amino was the fraction with the highest
contribution of organic N (39%), followed by the fraction of
N-unidentified (27%), the fraction of N-amide (18%) and N-hexosamine
(15%). The acacia plantation presented smaller natural abundance of 15N
and higher levels of total N and soil organic C, and increased organic
forms of N-hydrolyzed, when compared to the eucalyptus short-rotation
soil. This indicates the increase of labile N-organic forms in the soil
for the plants and reduction of humification of soil organic matter
(SOM) of acacia. Thus, the crops rotation with acacia after eucalyptus
contributed to the increase of organic forms in the soil, important for
the nutrition of plants, because they are potential sources of
nutrients to the plants in a short-time period
Carbon and nitrogen stocks in organic matter fractions in alfisol under eucalypt and pasture
O cultivo de florestas plantadas de eucalipto em \ue1reas de pastagem
tem propiciado altera\ue7\uf5es no estoque de C e N no solo, em
especial pelas diferentes caracter\uedsticas de cada planta e manejo
dos res\uedduos vegetais; o eucalipto pode localizar maior estoque de
C e N origin\ue1rio de res\uedduos da parte a\ue9rea na camada
superficial do solo, e aumentar a rela\ue7\ue3o C/N dos
res\uedduos vegetais em decomposi\ue7\ue3o. Tais diferen\ue7as
podem causar redu\ue7\ue3o no estoque de C e N nas
fra\ue7\uf5es qu\uedmicas, f\uedsicas e biol\uf3gicas do
solo, tanto nas fra\ue7\uf5es mais l\ue1beis, quanto nas mais
recalcitrantes. Este trabalho teve como objetivo avaliar os estoques de
C org\ue2nico total (COT) e N total (NT), estoque de C e N nas
subst\ue2ncias h\ufamicas (\ue1cidos f\ufalvicos, h\ufamicos
e h\ufaminas), fra\ue7\ue3o leve (C-MOL e N-MOL) e biomassa
microbiana (C-BM e N-BM) em amostras de solos coletadas nas camadas de
0-0,10, 0,10-0,20, 0,20-0,40, 0,40-0,60 e 0,60-1,00 m de profundidade,
na linha (EL) e entrelinha (EEL) do solo sob cultivo de eucalipto na
quarta rota\ue7\ue3o com seis anos de idade, e em \ue1rea de
pastagem cultivada com brachiaria (P). O estoque de carbono
org\ue2nico total e de carbono na fra\ue7\ue3o leve do solo nas
primeiras camadas do solo (at\ue9 0,60 m) foi superior na entrelinha
do eucalipto em compara\ue7\ue3o \ue0quele cultivado com pastagem
e na linha de cultivo do eucalipto, possivelmente favorecido pela
incorpora\ue7\ue3o de res\uedduos da colheita do ciclo anterior
de eucalipto na atual entrelinha. Por meio da determina\ue7\ue3o da
abund\ue2ncia natural de 13 na camada de 0-0,20m de solo verificou-se
que 29 e 37% do carbono presente na mat\ue9ria org\ue2nica do solo
(MOS) ap\uf3s 28 anos de cultivo derivaram do eucalipto (planta C3),
respectivamente, na linha e entrelinha, o que correspondeu \ue0 taxa
de ciclagem m\ue9dia da MOS nesse solo de 1,04% (linha) e 1,32%
(entrelinha) ao ano. No solo da entrelinha, observou-se que o C-C3
proveniente do eucalipto incrementou o estoque de C org\ue2nico do
solo, mesmo com a substitui\ue7\ue3o do C-C4 proveniente da
pastagem, ap\uf3s 28 anos de cultivo do eucalipto. Para o
nitrog\ueanio nas subst\ue2ncias h\ufamicas, verificou-se
estoques semelhantes entre o solo da entrelinha do eucalipto e o de
pastagem, e superior ao do solo da linha do eucalipto, at\ue9 1 m de
profundidade. O solo de eucalipto (EL e EEL) teve estoques de C e N na
biomassa microbiana semelhante \ue0quele cultivado com pastagem.The cultivation of eucalypt in areas of pasture has resulted in changes
of C and N storage in soil, mainly due to the different characteristics
of each plant and their biomass management; the largest stock of C and
N can be found under eucalypt, originating from the biomass at the soil
surface layer and increasing the C/N in decomposition of plant
residues. These differences may cause a decrease in the storage of C
and N fractions in the chemical, physical and biological soil, both in
the more labile, an the more recalcitrant fractions. This study aimed
to evaluate the stocks of total organic carbon (TOC) and total N (TN),
the stock of C and N in humic substances (fulvic acids, humic and
humin), the light fraction (C-MOL and N-MOL) and the microbial biomass
(C-BM and N-BM) in samples of collected from the layers 0-0.10,
0.10-0.20, 0.20-0.40, 0.40-0.60 and 0.60-1.00 m in depth, line (EL) and
interline (EEL) from the soil under eucalypt in the fourth rotation
with six years of age, and from an area of cultivated pasture with
Brachiaria (P). The total organic carbon stock and carbon in the light
fraction in the first layers of soil (0.60 m) was higher in the
interline of eucalypt compared with that from the cultivated pasture
and the line of eucalypt, probably favored by harvest residue from the
previous cycle of eucalypt buried in the current interline. By
determining the natural abundance of 13 in the 0-0.20m soil, it was
found that 29% and 37% of carbon present in the soil organic matter
(SOM) after 28 years of cultivation in the line and interline,
respectively, was derived from eucalypt (C3 plants), which corresponded
to an average rate of cycling of SOM in this soil of 1.04% (line) and
1.32% (interline) per year. In the soil interline it was observed that
the C-C3 from the eucalypt increased the stock of soil organic C, even
with the replacement of C-C4 from the pasture, after 28 years of
eucalypt cultivation. For nitrogen in humic substances, a similar stock
was obtained for the soil of the interline of eucalypt and that of the
pasture, which was higher than that of the soil line of eucalypt, up to
1 m deep. The soil of eucalypt (EL and EEL) showed a stock of C and N
in microbial biomass similar to that of cultivated pasture
Technologies for reducing water consumption by pineapples in the semi-arid region
ABSTRACT: In irrigated systems, the adoption of management methods like soil cover, polymers which absorb the water present in the soil and the utilization of shading screens can decrease the water consumption by the plants. This is achieved as these means protect the plant and soil against radiation and wavelengths of light undesirable for cultivation. However, for pineapple cultivation in the semi-arid climate regions, very little study has been done regarding these technologies. Hence, the present study conducted to assess the pineapple growth, production and quality when various kinds of soil cover, red shading screen and water absorption polymers are employed. To accomplish this, a field trial was performed utilizing four types of soil cover in the plots (plastic mulching; organic matter; organic matter + red shading screen 50%; plastic mulching + red shading screen 50% and the control (no cover).Two treatments were included in the subplots namely, either the absence or presence of a water-absorbing polymer in the planting hole (0.5 g per plant), arranged in subdivided plots. We adopted the Randomized Complete Block (RCB) , with three replications. The following aspects of the plants were studied: naturally flowering, stem diameter; leaf area index; D-leaf area and total leaf area; fruit weight with crown; fruit weight without crown; fruit length with crown; and fruit length without crown, as well as the traits of the post-harvest fruit, soluble solids, titratable acidity, pH and the soluble solids/titratable acidity ratio. Further, the productivity in t ha-1 and efficiency of water use (EUA) were ascertained. It was evident that the plastic mulching + 50% red shading screen favored the vegetative development and productivity of the ‘IAC Fantástico’ pineapple plants. The characteristics of the quality of the postharvest fruit were unaffected by the treatments. The shading screen reduced the percentages of natural flowering in the treatments which included organic matter + red shading screen 50% and plastic mulching + red shading screen 50%
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