The intensive use of the soil, associated with the application of chemical fertilizers, contribute to degradation processes that affect soil quality and crop production. The use of techniques that contribute to soil conservation and reduction of external inputsis important for the success of the agriculture, and hedging is an alternative. The objective of this study was to evaluate the phytomass production nutrient accumulation and contents, as well as rate of decomposition of different species used as cover plants. The experimental design was randomized blocks, with nine treatments distributed in three blocks. The treatments were: Canavalia ensiformes (L.) DC., Crotalaria spectabilis Roth, Crotalaria ochroleuca G. Don., Crotalaria juncea L., Dolichos lablab L., Stizolobium niveum (Roxb.) Kuntze, Stizolobium aterrimum Piper & Tracy, Neonotonia wightii (Wight & Arn.) J.A. Lackey and Pennisetum glaucum (L.) R.Br. The most recommended species as cover plants are C. ochroleuca and C. spectabilis for they produce more dry matter on the tops, 5.89 and 4.04 kg ha-1, in addition to greater accumulation of nutrients. C. ochroleuca and C. spectabilis had higher accumulation of N, P, K, Mg and S, and soil coverage with those species can be a good source of green manure. The recommended species for the highest coverage rate are: N. wightii; S. niveum and S. aterrimum. The recommended species for the lowest rate of decomposition are: S. aterrimum; S. niveum; P. glaucum and C. ochroleuca (0.245; 0.260; 0.264 and 0.276% month-1).
Guava is a perennial fruit, highly preferred by the Brazilian consumer and in increasing commercial exploitation in almost all the national territory. The most required nutrients are nitrogen, followed by potassium and calcium with great participation in the growth and physiology of guava. The objective of this study was to evaluate the effects of potassium doses in the soil without and with calcium in the physiology of Paluma guava plants. The experiment was carried out in a randomized complete block design in a 5 × 2 factorial arrangement, with K 2 O of 0, 45, 90, 135 and 180 g plant-1 year-1 , without and with 120 g plant-1 year-1 calcium from calcium nitrate. The variables analyzed were chlorophyll indices (a, b and total), chlorophyll fluorescence and gas exchange. The results were submitted to analysis of variance by the "F" test and the potassium doses were submitted to regression analysis, using SAS © software version 9.3. Guava plants fertilized with only potassium in the soil had higher photosynthetic rate, water use efficiency and instantaneous carboxylation efficiency. The addition of calcium and potassium to the soil increased chlorophyll a, b, total, variable fluorescence, maximum fluorescence, quantum efficiency, stomatal conductance, transpiration rate and internal carbon concentration in guava.
A B S T R A C TThis study aimed to evaluate the tolerance of castor bean cultivars under salt stress during the initial growth stage. The experiment was set in randomized blocks, in a 5 x 4 factorial scheme, resulting in 20 treatments, 5 salinity levels (0.6-control, 1.2, 1.8, 2.4 and 3.0 dS m -1 ) and 4 castor bean cultivars (BRS Energy, LA Guarani, BRS Gabriela and IAC 028)] with 3 replicates. At 30 days after sowing, plants were evaluated for growth, dry matter accumulation and salt tolerance. Increased salinity levels in the water used for irrigation reduced the growth of all the studied cultivars. The salt tolerance of the studied castor bean cultivars follows the following order: BRS Energia > BRS Gabriela = IAC 028 > LA Guarani.Tolerância de cultivares de mamoneira sob estresse salino R E S U M O Propôs, com este estudo, avaliar a tolerância de cultivares de mamoneira sob estresse salino durante a fase inicial de crescimento. Utilizou-se esquema fatorial 5 x 4, em delineamento em blocos casualizados, resultando em 20 tratamentos (5 níveis de salinidade (0,6 -controle; 1,2; 1,8; 2,4 e 3,0 dS m -1 ) x 4 cultivares de mamoneira (BRS Energia; LA Guarani; BRS Gabriela e IAC 028)] com 3 repetições. Aos 30 dias após a semeadura as plantas foram avaliados para crescimento, acúmulo de matéria seca e tolerância à salinidade. O aumento dos níveis de salinidade da água usada na irrigação reduziu o crescimento de todas as cultivares estudadas; a tolerância à salinidade das cultivares de mamoneira obedece a seguinte sequência: BRS Energia > BRS Gabriela = IAC 028 > LA Guarani.
R E S U M OObjetivou-se, neste trabalho, avaliar o crescimento e produção da mamona cv. BRS-188 Paraguaçu que tem sido recomendada para a região Nordeste do Brasil em relação à adubação orgânica, cobertura morta e níveis de reposição de água. Para isto foi desenvolvido o experimento em condições de campo, na cidade de Catolé do Rocha, PB, usando-se um delineamento experimental em blocos casualizados com fatorial 2 x 2 x 4, constituído de dois níveis de reposição de água em função da evapotranspiração da cultura -ETc de 100 e 50% no solo sem e com cobertura morta (Cenchrus ciliares L) e quatro níveis de biofertilizante bovino (0; 1,2; 2,4 e 3,6 L planta -1 ), aplicados ao solo totalizando 16 tratamentos com três repetições e dez plantas por tratamento totalizando 48 parcelas experimentais. As plantas irrigadas com 50% da ETc, no solo com cobertura morta e biofertilizante bovino na dose de 3,6 L planta -1 atingiram áreas foliares e produções semelhantes às plantas cultivadas em sistema convencional sem cobertura e irrigadas com 100% da ETc.Growth and production of castor bean BRS Paraguaçu under irrigation, soil mulching and organic fertilization A B S T R A C TThe objective of this study was to evaluate the growth and production of castor bean BRS-188 Paraguaçu, which has been recommended for the Northeast of Brazil in relation to organic fertilization, mulching and levels of water replacement. For this, an experiment was conducted under field conditions in the municipality of Catolé of Rocha-PB, using a randomized complete block design with factorial 2 x 2 x 4, consisting of two levels of replacement of water through irrigation due to the crop evapotranspiration -ETc 100 and 50%, with and without mulch (Cenchrus ciliares L) and four levels of bovine biofertilizer (0, 1.2, 2.4 and 3.6 L plant -1 ), applied to the soil, totaling 16 treatments with three replications and ten plants per treatment totaling 48 experimental plots. Plants irrigated with 50% of ETc, under mulch and bovine fertilizer at a dose of 3.6 L plant -1 reached leaf area and similar productions to plants grown in conventional system without mulch cover and irrigated with 100% ETc. Palavras-chave:Ricinus communis L. sistema de cultivo manejo de água
Onion is the third vegetable crop in economic importance for Brazil, only behind potato and tomato, and responds with increased production to the use of organic and mineral fertilizers. The objective of this study was to evaluate the effect of doses of cattle manure and nitrogen (N) on onion growth and yield. The experimental design used was randomized blocks, in 6 x 2 factorial scheme, corresponding to six doses of cattle manure (0; 10; 20; 30; 40 and 50 t ha-1), in the presence and absence of N, with four repetitions. The variables studied were: shoot fresh and dry masses, total and marketable bulb yields, percentage of bulbs classified and leaf N content. There was an interactive effect (p ≤ 0.05) of cattle manure and N doses on shoot fresh and dry masses, total and marketable yields, classification of bulbs according to transverse diameter and N concentration in onion bulbs. The optimal dose for marketable yield of bulbs is 27 t ha-1 of cattle manure in the presence of N.
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