Effects of Nitrogen Forms on Root System Development, Physiological Traits, and Dry Matter Production of Rice

The objective of this work was to study morphogenic characteristics, and dry matter production of roots and shoots of marandu palisadegrass (Brachiaria brizantha cv. Marandu) submitted to combinations of nitrogen and potassium, in a nutritive solution, employing silica as substrate. The experiment was carried out in a greenhouse during the summer. It was used a 5² fractionated factorial scheme with 13 combinations of nitrogen and potassium, which were distributed in a randomized block design, with four replications. The nitrogen × potassium interaction was significant for the number of tillers and leaves, for leaf area, for shoots and root section dry mass, for total length and surface and specific length and surface in the roots. Production of aerial part dry mass positively correlated with the number of tillers and leaves and grass leaf area. Nitrogen rates modulated the root system development, and the root specific length and surface decreased when high rates of nitrogen and potassium were supllied. Nitrogen and potassium influence Marandu palisadegrass morphogenic characteristics, which are determinant for grass dry matter production.

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Effect of the use of pre- and post-emergence herbicides on nodulation and production of cowpea (Vigna unguiculata L.) in the Amazonian savannah

Agronomía Colombiana ◽

10.15446/agron.colomb.v38n2.82196 ◽

2020 ◽

Vol 38 (2) ◽

pp. 280-286

Author(s):

Anna Bárbara De Souza Cruz ◽

José de Anchieta Alves de Albuquerque ◽

Paulo Roberto Ribeiro Rocha ◽

Leandro Torres de Souza ◽

Diego Lima de Souza Cruz ◽

...

Keyword(s):

Grain Yield ◽

Root System ◽

Weed Control ◽

Dry Matter ◽

System Development ◽

Control Strategies ◽

Control Measure ◽

Block Design ◽

Root System Development ◽

Randomized Block Design

As a control measure against weeds, the use of herbicides is an effective and inexpensive alternative. However, there are no products recommended for the cultivation of cowpea in Brazil, making it necessary to search for alternative solutions. The objective of this study was to evaluate the effect of herbicides applied in the pre- and post-emergence on cowpea nodulation and production under conditions of the Amazonian savannah. Two experiments were carried out in a randomized block design with four replicates, using the cowpea cultivar BRS Aracê subjected to the pre-emergence herbicides: Metribuzin, Sulfentrazone, Smetolachlor, Pendimethalin, Oxadiazon, Alachlor, Metribuzin + Pendimethalin, Metribuzin + Alachlor and Quizalofop-p-ethyl, Bentazon, Fomesafen, Imazethapyr, Imazamox + Bentazon, Quizalofop-p-ethyl + Imazethapyr, Quizalofop-p-ethyl + Imazamox and Quizalofop-p-ethyl + Bentazon, and post-emergence herbicides: Quizalofop-p-ethyl, Bentazon, Fomesafen, Imazethapyr, Imazamox + Bentazon, Quizalofop-p-ethyl + Imazethapyr, Quizalofop-p-ethyl + Imazamox, and Quizalofop-p-ethyl + Bentazon. The number of nodules in each plant, the dry matter of nodules, dry matter of roots and the grain yield were evaluated. According to the results obtained, the management of weeds in pre- or post-emergence according to the herbicide used affects the nodulation and productivity of cowpea under the conditions of the Amazonian savannah. The herbicides Metribuzin in preemergence,and Fomesafen and the mixture of Quizalofop-pethyl + Imazethapyr in post-emergence are not recommended for weed control in cowpea. The application of Oxadiazon, Alachlor, and Pendimethalin in pre-emergence can be considered interesting because they do not inhibit the development of the root system or the nodulation of cowpea which provides agreater grain yield. Regarding weed control strategies at postemergence, the application of the herbicide Imazethapyr and the combination of the herbicides quizalofop-p-ethyl + imazamox, Quizalofop-p-ethyl + Bentazon and Imazamox + Bentazon allow satisfactory levels of grain yield, root system development and nodulation of cowpea.

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Simulating Root System Development of Short-duration Pigeonpea

Experimental Agriculture ◽

10.1017/s0014479700025874 ◽

1996 ◽

Vol 32 (1) ◽

pp. 67-78 ◽

Cited By ~ 4

Author(s):

Gayatri Devi O. Ito ◽

R. Matsunaga ◽

S. Tobita ◽

T. P. Rao ◽

N. Vidyalakshmi ◽

...

Keyword(s):

Root System ◽

Dry Matter ◽

System Development ◽

Chemical Properties ◽

Climatic Data ◽

Growth Data ◽

Soil Layers ◽

Root System Development ◽

Physico Chemical ◽

Logistic Functions

SUMMARYLength and weight of pigeonpea roots were measured weekly in different soil layers and compared with estimates obtained from a root simulation model using daily climatic data, soil physico-chemical properties and dry matter allocation to roots. Daily moisture content and temperature at different soil depths were well simulated using sub-routines from the CERES-Maize model. Daily allocation of dry matter to roots was calculated from logistic functions fitted to the growth data for shoots and roots. Although root length and weight tended to be underestimated by the model, regressions between measured and simulated root growth were highly significant so that the model could, with a few modifications, be used to predict root system development.

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