Avaliação de diferentes densidades de semeadura e da poda na produtividade de sementes de Crotalaria juncea L.

Abstract

Evaluation of different plant densities and pruning in seed yield of Crotalaria juncea L.There is currently a growing interest in the practice of green manure and its effects on agricultural production systems. In order to evaluate different seeding rates and effects of pruning on seed production of C. juncea an experiment was conducted in the Unit of Research Support in UENF in Campos -RJ. The experiment was arranged in split-plots, with pruning (and without) in the plots and sowing densities (10, 15, 20, 25 and 30 per plant) in the subplots in a randomized block design with four replications. The experimental units consisted of six rows spaced 0.5 m apart, and 4 feet long. Without pruning, crotalaria plants were 0.634 m higher. The number of branches of pruned crotalaria plants was larger than the non-pruned plants and the density of 10 and 15 plants per meter had lager number of branches. At the density of 30 plants per meter, the plants produced higher amount of dry matter. With pruning, the crotalaria plants showed on average 7.2 small pods, while the non-pruned plants had mean of 5.1 small pods. At the density of 30 plants per meter, there was approximately 25% more seeds per large pod of pruned plants in relation to the seeds of large pods of non-pruned plants. Besides, at this density, plants had larger number of seeds per large pod compared with other densities. It is recommended pruning and density of 10 plants per meter due to the lower cost of seeds and seeds with more vigor.

Biomass of Crotalaria juncea as a function of plant densities in the semiarid region of Northeastern Brazil

“…1). This result is corroborated by other studies, like that of Eiras and Coelho (2012), who observe an increase in SDM as plant density increased from 20, 30, 40, 50 and 60 plants m -2 , keeping 50 cm between rows. With the same spacing, Teodoro et al (2016) obtain an increase in SDM with higher densities of 20, 40 and 60 plants m -2 .…”

“…In the study by Pereira et al (2005), the highest SDM is obtained both by increasing the number of plants in the row (5, 10, 20 and 40) as well as by decreasing the row spacing (120, 60 and 30 cm). As plant densities tested by Eiras and Coelho (2012) result in similar dry mass per plant, the increase in plant density per area is determinant for the increase in SDM, as stated by Teodoro et al (2016). Similarly, in our study the SDM increased with higher plant density per area, but SDM per plant decreased.…”

“…The development of species like this one is influenced by the interaction between photoperiod and temperature, the sowing date and the latitude (Amabile et al, 2000). Sunn hemp is a photoperiod-sensitive species and its flowering is induced by the shortening of day length, resulting in a decrease in biomass production (Lima et al, 2010;Eiras and Coelho, 2012). In Mossoro, the length of the day varies slightly, ranging from 11.8 h in June to 12.4 h in December, which is the photoperiod range in which Santos and Campelo Júnior (2003) observe the shortest time until sunn hemp flowering.…”

“…Mitigation of soil degradation can be achieved by more sustainable management practices, such as crop rotation and cultivation of species for green manuring and soil cover (Lima et al, 2010;Eiras and Coelho, 2012). Green manures, incorporated into soil management or used to cover the soil (Espíndola et al, 2005) protect and enrich the soil with SOM and nutrients and reduce the use of industrialized inputs while mitigating environmental degradation (Mateus and Wütke, 2006).…”

Microbial Communities in Soil Cultivated with Muskmelon under Different Management Systems

“…The use of plant soil cover has been considered one of the main alternatives for conservation and improvement of the agricultural environment, reducing soil degradation, especially in regard to organic matter, since this practice improves the physical, chemical, and biological properties of the soil (Eiras and Coelho, 2012).…”