Dry Mass Accumulation, Nutrients and Decomposition of Cover Plants

Abstract

The use of cover crops is an important strategy for soil management in the Brazilian Cerrado to improve no-tillage (NT) systems. For this, it is necessary know the potential of cover crop species for biomass production, nutrient cycling, and persistence of residues on the soil surface in soils and climatic conditions of this biome. Thus, the experiment was developed to evaluate the agronomic potential of cover crops cultivated on an Oxisol (Latossolo Amarelo) in the Cerrado of Piauí, Brazil. The experiment was conducted from January 2015 to July 2016. The experimental design was in randomized blocks with 11 treatments and four replicates. The treatments consisted of single and intercropped cover species. The evaluations were: dry mass production, nutritional composition of the plants, nutrient accumulation by dry mass produced and decomposition rate of the dry mass produced for each treatment. The higher dry matter production was obtained with Crotalaria juncea, Cajanus cajan (cv. IAC-Fava larga), Pennisetum glaucum and Brachiaria ruziziensis. The lower dry matter production was obtained with Mucuna aterrima, and mix of Crotalaria spectabilis + Pennisetum glaucum. The higher nutrients accumulation in the plants occurred for Cajanus cajan (cv. IAC-Fava larga), Crotalaria juncea and Crotalaria spectabilis. The cover plants studied presented good potential for soil conservation, due to the permanence of residues on the surface, except for Mucuna aterrima and Crotalaria spectabilis.

Grasses and Legumes as Cover Crops Affect Microbial Attributes in Oxisol in the Cerrado (Savannah Environment) in the Northeast Region1

“…Microbial biomass carbon (mg 100 g -1 ) for 105 days of incubation after incorporation of grasses and legume straw in an Oxisol. The straw of Pennisetum glaucum (PG) and Brachiaria brizantha (BB) have a C/N ratio > 30.0 (Table 1) and approximately 40% of the accumulated phytomass of Pennisetum glaucum is from the stem, which consists of lignified tissues with a higher C/N ratio than the leaves (SOUSA et al, 2019). This means that the N immobilization process predominates over N mineralization (MOREIRA;SIQUEIRA, 2006).…”

“…Knowing the temporal dynamics of N mineralization or immobilization of the different cover crops it is important to manage the agricultural systems in the Cerrado. It is also necessary to choose the correct species to be used and the ideal moment to sow the following crop so that the decomposition and release of nutrients by the cover plants can happen in the period of greater demand by the following crop (SOUSA et al, 2019).…”

“…The southwest region of Piauí is part of the Brazilian agricultural frontier called MATOPIBA (Maranhão, Tocantins, Piauí and Bahia), which is currently undergoing a great agricultural expansion and intensification of land use for the cultivation of grains, fibers, energy materials, perennial crops and irrigated agriculture (FONTANA et al, 2016;SOUSA et al, 2019). Management systems aimed at soil conservation have been widely discussed and applied, such as crop rotation, the use of cover plants, non-till or minimal tilling, which are directed at mitigating the negative effects of conventional management practices in soils, due to the loss of nutrients, of organic matter, the reduction of microbial diversity, changes in the structure of the edaphic fauna, increased gas emission, besides chemical and physical degradation (GUO et al, 2018;ZHANG et al, 2016).…”

Carbono E Nitrogênio Do Solo Em Povoamento De Schizolobium Parahyba Var. Amazonicum Estabelecido Em Diferentes Espaçamentos

“…A maior disponibilidade de N do solo resulta em maiores processos de mineralização da matéria orgânica. Espécies da família Fabaceae, por possuírem alto teor de N em seus tecidos vegetais, consequentemente apresentam baixa relação C/N (SOUSA et al, 2019). WANG et al (2014), esclarecem que relações C/N maiores que 30 indicam a imobilização de N no solo, enquanto valores menores que 20 favorecem a mineralização e maior disponibilidade de N para as plantas.…”

Organic matter compartments in an Ultisol under integrated agricultural and livestock production systems in the Cerrado

“…Maize intercropped with Urochloa contribute residues to the surrounding system that have a high C/N ratio and high lignin quantity compared to the residues derived from soybean/ millet crops, which allows the straw greater perenniality (GARCIA et al, 2014;SOUSA et al, 2019). In this sense, when observing the trends of the results presented here, which were processed through uni and multivariate statistical analyses showed that the area without recent history of soil tillage which had the CLI system introduced 4 years ago, was most efficient in increasing soil C (121 t/ha) and N (3.4 t/ha) (Table 2), since it is linked to the largest number of studied C and N response variables (Figure 4).…”