Crop rotation biomass and arbuscular mycorrhizal fungi effects on sugarcane yield

Abstract

Sugarcane (Saccharum spp.) is an important crop for sugar production and agro-energy purposes in Brazil. In the sugarcane production system after a 4-to 8-year cycle crop rotation may be used before replanting sugarcane to improve soil conditions and give an extra income. This study had the objective of characterizing the biomass and the natural colonization of arbuscular mycorrhizal fungi (AMF) of leguminous green manure and sunflower (Helianthus annuus L.) in rotation with sugarcane. Their effect on stalk and sugar yield of sugarcane cv. IAC 87-3396 grown subsequently was also studied. Cane yield was harvested in three subsequent cuttings. Peanut cv. IAC-Caiapó, sunflower cv. IAC-Uruguai and velvet bean (Mucuna aterrimum Piper and Tracy) were the rotational crops that resulted in the greater percentage of AMF. Sunflower was the specie that most extracted nutrients from the soil, followed by peanut cv. IAC-Tatu and mung bean (Vigna radiata L. Wilczek). The colonization with AMF had a positive correlation with sugarcane plant height, at the first cut (p = 0.01 and R = 0.52) but not with the stalk or cane yields. Sunflower was the rotational crop that brought about the greatest yield increase of the subsequent sugarcane crop: 46% increase in stalk yield and 50% in sugar yield compared with the control. Except for both peanut varieties, all rotational crops caused an increase in net income of the cropping system in the average of three sugarcane harvests. Key words: green manure, legumes, biological nitrogen fixation, sugarcane stalk yield Produção de biomassa e presença de fungos micorrízicos arbusculares em culturas utilizadas em rotação com a cana-de-açúcarRESUMO: A cana-de-açúcar (Saccharum spp.) vem sendo cultivada no Brasil para produção de açúcar e agroenergia. Em seu sistema de produção, após um ciclo de 4 a 8 anos, é possível a rotação com plantas de cobertura, antes do seu replantio, para melhoria do solo e geração de renda. Estudou-se a caracterização e produtividade de biomassa de leguminosas (como adubos-verdes) e girassol (Helianthus annuus L.), a ocorrência natural de micorrizas, o teor de açúcar e a produtividade em colmos da cana-de-açúcar IAC 87-3396 e a viabilidade econômica desse sistema com cultivo após as opções de rotação, com quantificação da produtividade durante três cortes consecutivos. O amendoim (Arachis hypogaea L.) cv. IAC-Caiapó, girassol cv. IAC-Uruguai e mucuna-preta (Mucuna aterrimum Piper and Tracy) foram as culturas que apresentaram maior percentagem de colonização por fungos micorrízicos. O girassol foi a planta de cobertura que mais extraiu nutrientes do solo, seguido por amendoim (Arachis hipogaea L.) cv. IAC-Tatu e feijão-mungo (Vigna radiata L. Wilczek). A colonização por fungos micorrízicos mostrou correlação positiva com a altura de plantas de cana no primeiro corte (p = 0,01 e R = 0,52), mas não se correlacionou com a produtividade de colmos ou açúcar. No primeiro corte, o girassol foi a cultura de rotação que ocasionou o maior aumento de produtividade, da ord...

15N-labeled nitrogen from green manure and ammonium sulfate utilization by the sugarcane ratoon

“…Sugarcane crops in Brazil are replanted every five to ten years. In southeastern Brazil, the interval between the last sugarcane harvest and the new plantings occurs during the spring-summer season, under high temperature and heavy rainfall (almost 1,000 mm in six mont hs - Ambrosano et al, 2010).…”

Challenges, Opportunities and Recent Advances in Sugarcane Breeding

“…Low P soil conditions (e.g., ~20 mg kg -1 ) tend to foster symbiotic infection rates (Takashasi, 2005). Crop rotation also benefits mycorrhizal association (Ambrosano et al, 2010) with observed 30% yield increase during three harvests along with increase of sugar content. The plant's genetic inheritance regarding mycorrhization is still elusive, but sugarcane geneticists and physiologists should put efforts in providing tools to enable breeding programs to create genotypes with higher mycorrhization potential, which would certainly have great impact on crop management costs, plant's fitness to adverse conditions and plantation sustainability.…”

Crop Rotation Biomass and Effects on Sugarcane Yield in Brazil

“…Above ground dry matter 2 Grain yield 2 Natural infection of AMF 2 Analysis of variance were made after data transformation to log (×).Adapted from [14]. Table 4.…”

“…Sugarcane crops in Brazil are replanted every five to ten years. In southeastern Brazil, the interval between the last sugarcane harvest and the new plantings occurs during the spring-summer season, under high temperature and heavy rainfall (almost 1,000 mm in six months) [14].…”