Zornia (Zornia glabra)

Datasheet

Description

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Common names

Mariguana do Brasil, zornia [Portuguese, Brazil]; alverjilla, cargadita, encarrugada, urinaria, zarzabacoa de dos hojas, zornia [Spanish]

Species

Zornia glabra Desv. [Fabaceae]

Synonyms

Zornia diphylla (L.) Pers. var. elatior Benth., Zornia diphylla (L.) Pers. var. perforata (Vogel) Kuntze, Zornia diphylla (L.) Pers. var. reticulata (Sm.) Benth., Zornia perforata Vogel

Taxonomic information

Many Zornia spp. have bifoliolate leaves and have been classified as or confused with Zornia diphylla. The above common names have been associated with Zornia diphylla (Cook et al., 2020).

Related feed(s)

Description

Zornia (Zornia glabra Desv.) is a perennial legume grown for forage in Latin America and Africa despite its relatively low palatability. It was investigated in the 1980-1990s as a promising forage, but interest in the plant has decreased since.

Morphology

Zornia glabra is a leafy perennial legume up to 60 cm tall, largely glabrous. The stems are ascending to erect. The leaves are bifoliolate, glabrous or puberulent. The inflorescence is an axillary spike of papillonaceous, yellow with red striations flowers (Cook et al., 2020).

Uses

Zornia glabra is grown as a forage legume in improved pastures and in intercropping systems (Cook et al., 2020). It has been undersown in cassava fields to prevent erosion but caused a decrease in cassava production (Leihner, 2002).

Distribution

Zornia glabra is native to Brazil, French Guiana, Guyana, Suriname. It is found in humid and subhumids tropics where annual rainfall is over 1500 mm and annual average temperature is 23-27°C. It does well on ultisols in its native environment, and could adapt to ultisols and oxisols in the wet tropics elsewhere. These soils have low fertility and pH as low as 4. Zornia does not tolerate shade but is able to recover from fire thanks to soil seeds and below ground crown (Cook et al., 2020).

Forage management

Management

Zornia glabra can be sown at 2–3 kg/ha., alone or in association with grasses like gamba grass (Andropogon gayanus or Megathyrsus maximus) (Cook et al., 2020). Zornia glabra reseeds readily. . Zornia does not seem to establish readily as the percentage of ground covered after 22 weeks remained below 30% and was the lowest of all forage legumes assessed in the same experiment (Muhr et al., 1999). It was recommended to cut zornia every 6 weeks so as to have a good trade-off between forage quality (CP >12%) and yield (>4 t DM/ha)(Agbemelo-Tsomafo et al., 1993). A later study suggested to have it cut every 3 weeks (Barnes et al., 1996). In an attempt to limit soil erosion, Zornia glabra was undersown in cassava crop but it had deleterious effect on cassava root development (- 40%) (Leihner, 2002).

Yields

In 1989, in the Eastern Plains of Colombia, yield was 0.9 t/ha for Zornia glabra CIAT 7847 (Pizarro et al., 1989). These yields were in the same range in Ghana, in 1996. An interesting fact was that Zornia glabra yields did not vary with season and were identical in wet and dry season. Compared to other legumes, Zornia's yield ranked poorly (Barnes et al., 1996). Recent report suggest however higher yields of 2-2.5 t DM /ha/season (Cook et al., 2020).

Environmental impact

Soil improver and soil erosion control

Zornia glabra is a N-fixing legume that readily nodulates when it is sown in its native environment. It was shown that its integration in natural fallow, despite dry season forage utilisation, increased grain yields of subsequently grown maize by up to 52% on experimental site in Nigeria (Muhr et al., 1998). As a ground cover, zornia could hardly cover 30% of the ground in two sites (one experimental and one managed by farmer) of South West Nigeria (Muhr et al., 1999).

Nutritional aspects

Nutritional attributes

Despite the numerous trials that assessed Zornia glabra in the 1980s, there are few data on its composition, except on its protein content. Zornia glabra is generally a protein-rich forage, with a protein content over 20% DM recorded in Colombia, though values lower than 15% or even 10% DM have been noted in West Africa.

Ruminants

Palatability

Zornia glabra was reported to have fairly low palatability, inferior to that of Centrosema acutifolium, and comparable to that of Desmodium velutinum (Cook et al., 2020). However, this was not consistent with earlier observations of zebu steers, who were found to have a high utilization of zornia or to prefer zornia among 11 other forages in cafeteria grazing trials (Abaunza et al., 1991; Schultze-Kraft et al., 1989). In Colombia, a 14-day experiment showed that Zornia glabra did not cause any digestive issues in wethers and that animals could have high (81 g DM/kg BW^0.75/day), though variable, forage intake with this forage. Zornia ranked second after Centrosema sp. and it was concluded that it had a medium palatability (CIAT, 1984).

Digestibility and degradability

In Columbia, the in vitro DM digestibility of Zornia glabra was quite high (72%) and higher than than of other tested legume forages. (Abaunza et al., 1991). DM digestibility obtained in sheep was 60% (CIAT, 1984). In southwest Nigeria, Zornia glabra assessed among 12 forages legumes to improve natural fallow was found to rank second behind Arachis pintoi for DM degradability. Zornia DM degradability was above 50% in wet and dry season while there was a decrease in mid season to 40% (Muhr et al., 1999).

Rabbits

No information seems available in the international literature (July 2021) on the possibility of use of Zornia glabra forage, fresh or dry, in rabbit feeding. However, this forage could be used in cattle feeding, and an other forage of the same genus (Zornia glochidiata) could be included in rabbit diets at up to 30% in the diet without causing health problems, with an optimum at 10% (Ogunsane al 2011). Based on its chemical composition, estimated digestible energy of Zornia glabra forage is similar to that of dehydrated alfalfa (8.3 MJ/kg DM). It would be interesting to test this forage in rabbit nutrition through direct experiments.

Nutritional tables

Tables of chemical composition and nutritional value

Zornia (Zornia glabra), aerial part, fresh

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used