Green Manures in 'Kent' Mango Orchard

Abstract

Continuous and intensive use of the soils of the Lower-Middle São Francisco River Valley (Vale do Submédio São Francisco) through the growing of mango trees in irrigated systems has caused soil degradation and consequently threatened the quality and sustainability of this agribusiness activity in the region. The predominant soil cover in this region has a sandy texture and low organic matter content and water retention capability, which are further compromised by high temperatures and insolation which cause serious restrictions to agricultural productivity when associated with inadequate irrigation management. The aim of this paper was to study crop systems (green manures) used as cover crops and green manure in the establishment of a 'Kent' mango tree orchard by means of quantification and mineral composition of the plant matter resulting from each one of the formative prunings. The leguminous plants used in the intercropped plant mixture were: Calopogonium mucunoide Desv., Crotalaria juncea L., Crotalaria spectabilis Roth., Canavalia ensiformes DC., Cajanus cajan L., Dolichos lablab L., Mucuna aterrina L., and Mucuna conchinchinensis L. The mixture also included non-leguminous species, such as: Sesamum indium L., Chysantemum peruviamum maius, Ricinus communis L., Penissetum americanum L. and Sorghum vulgare Pers. Three plants per plot in four replications were used for evaluations. The mean value of fresh matter production resulting from each one of the four prunings of establishment of the orchard showed that the intercropped plant species mixture with 75% leguminous plants and 25% non-leguminous plants increased plant vigor. Increases were 16.6, 19.7, 45.1 and 23.9% at pruning 1, 2, 3 and 4, respectively, when compared to the treatment of spontaneous vegetation without soil turnover. Significant differences were observed between the treatments in relation to total content of nitrogen, phosphorus, potassium, calcium, and magnesium in the leaves and accumulated branches at the end of the formative prunings of the plants. The use of intercropped plant species mixtures allows the orchard establishment period to be shortened, which makes it possible to advance the time for beginning management of flower induction and production of mango trees of the 'Kent' cultivar.

Nitrogen fixation of Poaceae and Leguminoseae in a green manure experiment in the Brazilian semiarid region

“…As C4 species have higher photosynthesis potential than C3 species, they can produce more biomass than legume species (Pedroso et al, 2014). Planting these Poaceae species as sole green manure crops is not a common practice but they have been lately tested as part of mixtures of several species planted together (Snapp et al, 2005;Miyazawa et al, 2010;Pimentel et al, 2011;Feitosa et al, 2015;Mouco et al, 2015;Pereira Filho et al, 2016). These mixtures have the potential to maximize biomass production but little is known of their capacity to fix N. Perhaps the lack of information comes from the variability of fixation in the Poaceae, apparently high in some places (Montañez et al, 2009;Morais et al, 2012;Taulé et al, 2012;Baptista et al, 2014;Santos et al, 2017) but completely absent in other places (Biggs et al, 2002;Hoefsloot et al, 2005).…”

“…Green manure may counterbalance the rapid decrease in soil organic matter brought by the high rates of organic matter decomposition, which occur under conditions of high temperature and ultraviolet radiation (Parton et al, 2007;King et al, 2012) and high soil humidity (Lee et al, 2014). In spite of green manure mixtures being a growing practice in the region (Pimentel et al, 2011;Feitosa et al, 2015;Mouco et al, 2015;Pereira Filho et al, 2016), determinations of their biomass production and especially N fixation are scarce. Periodical incorporation of spontaneous vegetation is also a growing and less studied practice in the region.…”

Optimizing multifunctional agroecosystems in irrigated dryland agriculture to restore soil carbon – Experiments and modelling

“…To estimative of C input from aboveground and belowground biomass we assumed a C content of 45% dry matter. Further details about the long-term field experiments can be found elsewhere (Antonio et al, 2019;Brandao et al, 2017;Freitas et al, 2019;Giongo et al, 2016;Mouco et al, 2015).…”

Cover crops mixtures with more legumes maximize biomass and N input in irrigated fruit crops in Brazil

“…Although many studies concluded that these green manures are a viable practice (Hunter et al, 2021;De Notaris et al, 2021;Hu et al, 2023) they are not used in many irrigated areas of the world. In the large irrigated fruit producing areas in the São Francisco river valley, in the Brazilian semi-arid northeast region, the practice of cover crops is almost completely absent (Pimentel et al, 2011;Feitosa et al, 2015;Mouco et al, 2015;Pereira Filho et al, 2016). To promote their use, appropriate species must be sellected and the best management of the produced biomass has to be determined (Ferreira Neto et al, 2017;De Notaris et al, 2021).…”