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Accueil du site → Master → Afrique du Sud → 2022 → Growth, leaf gaseous exchange and nutritive value of selected summer forage legumes and their contributions to succeeding winter grass (Secale cereale) in District Agro-ecological zone of Limpopo Province

University of Limpopo (2022)

Growth, leaf gaseous exchange and nutritive value of selected summer forage legumes and their contributions to succeeding winter grass (Secale cereale) in District Agro-ecological zone of Limpopo Province

Lekgothoane, Philemon Lesetja

Titre : Growth, leaf gaseous exchange and nutritive value of selected summer forage legumes and their contributions to succeeding winter grass (Secale cereale) in District Agro-ecological zone of Limpopo Province

Auteur : Lekgothoane, Philemon Lesetja

Université de soutenance : University of Limpopo

Grade : Master of Science (MS) Pasture Science 2022

Résumé partiel
In South Africa, livestock production is a rapidly growing business in the agricultural sector contributing up to 46.9% of the gross domestic value. The shortage of adequate, good quality forage during the winter months is one of the biggest problems confronting livestock farmers in the Limpopo Province. This study was initiated in 2019 to evaluate the production potential and nutritive value of different summer annual forage legumes, namely sunnhemp (Crotalaria juncea), forage cowpea (Vigna unguiculata), lablab bean (Lablab purpureus), and pigeon pea (Cajanus cajans), and their impact on succeeding winter stooling ryegrass (Secale cereale), at the University of Limpopo experimental farm Syferkuil and a Cooperative farmers’ field at Ofcolaco. The study was evaluated in a randomized complete block design with four replications. Dry matter yield, crude protein, crude protein yield, leaf chlorophyll content, Normalized Difference Vegetative Index (NDVI), and leaf gaseous exchange parameters of forage crops were statistically analysed with Statistical Analysis System (SAS), Enterprise Version 9.4, using the least significant difference (LSD) method for mean comparison. Pigeon pea biomass accumulation was 57% lower than the average of the three other legumes at Syferkuil. Sunnhemp produced superior biomass (P<0.05) compared to the other three species, reaching a peak yield of 3142.4 kg.ha-1 and 8970.8 kg ha-1 at Syferkuil and Ofcolaco, respectively. Cowpea and lablab produced similar biomass at Syferkuil. The crude protein content of the forage species ranged from 22.91% to 26.82% at Syferkuil and 17.03% to 23.84% at Ofcolaco. Leaf chlorophyll content differed (P<0.001) among the forage legume species at both locations with cowpea producing the highest chlorophyll content at Syferkuil, whereas at Ofcolaco, pigeon pea constantly produced the highest chlorophyll compared to other species. Pigeon pea was the only species rated moderately healthy with Normalised Difference Vegetative Index (NDVI) readings at Syferkuil, unlike at Ofcolaco where all forage legumes were rated as very healthy. At Syferkuil, no root nodules were observed among all the forage legumes at all sampling dates but at Ofcolaco, nodules were produced at 44 DAE with cowpea producing the highest, 92.32% higher than the average of sunnhemp, lablab, and pigeon-pea. At this location pigeon pea did not nodulate. The transpiration rate at Syferkuil was significant (P<0.01) among the species starting with a low transpiration rate from 24 days after planting and reaching their peak at 66DAE. Overall, pigeon pea had the highest (P<0.05) mean transpiration rate compared to the other species. At Ofcolaco the forage legume treatment did not have any significant (P>0.05) influence on transpiration rate, stomatal conductance and sub-stomatal conductance.

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Page publiée le 16 janvier 2023