Screening of legumes for veld reinforcement peulgewastoets vir veld verbetering

Abstract

In order to test their suitability for veld reinforcement, Desmodium intortum, D. sandwiceme, D. uncinatum,Glycine wightii, Listia heterophylla, Lotononis bainesii, Macroptilium atropurpureum, Stylosanthes frutícosa, S. humilis and three strains of S. guianensis were seeded in December 1970 in disced veld at Marandellas (sand) and near Mazoe (clay). Starting in December 1971 the legumes were grazed in common at two stocking intensities during the wet season only, the dry season only or year‐round, using a simulated rotational grazing system.

Legume seedling mortality was high on the sand and only M. atropurpureum and the five Stylosanthes lines had plant densities in the second season greater than 1 plant/m². On the clay establishment was better and all legumes except L. heterophylla had densities greater than 1 plant/m².

Oxley fine‐stem stylo was the only legume to persist and spread on the sand but on the clay a much wider range of legumes persisted, although all were adversely affected by a hot fire in July 1976. D. uncinatum, L. heterophylla and L. bainesii were the most persistent legumes on the clay and spread widely.

Grazing treatment did not greatly affect the persistence or spread of the legumes. However, at both sites the frequency of the undesirable grass Sporobolus pyramidalis increased in the plots grazed during the wet season. On the clay this was associated with a reduction in the frequency of Hyparrhenia spp.

The possible shortcomings and the applicability of this type of trial are discussed.

Uittreksel

Die volgende peulgewasse is op 10 Desember 1970 te Marandellas (sandgrond) en naby Mazoe (kleigrond) op veld, met ‘n snyeg gerol, gesaai om hulle bruikbaarheid vir veldverbetering te toets: Desmodium intortum, D. sandwicense, D. uncinatum, Glycine wightii, Listia heterophylla, Lotononis bainesii, Macroptilium atropurpureum, Stylosanthes fruticosa, S. humilis en drie seleksies van S. guianensis.

Sedert Desember 1971 is die peulgewasse in een groep teen twee beweidingspeile gedurende of die reënseisoen of die droëseisoen of ononderbroke bewei deur ‘n skyn wisselweidingstelsel

Die oorlewing van peulplante saailinge op die sandgrond was laag en slegs M. atropurpureum en die vyf Stylosanthes spp. het gedurende die tweede seisoen ‘n plantpopulasiedigtheid van 1 of meer plante m^–2 gehad. Op die kleigrond was die oorlewing beter en het slegs L. heterophylla in die tweede seisoen ‘n stand van minder as 1 plant m^–2 gehad.

Die enigste peulgewas wat op die sandgrond gedy het was die Osleyfynstam Stylo maar op die kleigrond het meer peulgewasse bly voortbestaan hoewel almal deur ‘n warm veldbrand gedurende Julie 1976 beskadig is. Op kleigrond het D. uncinatum, L. heterophylla, L. bainesii wydverspreien sterkste oorlewing getoon.

Die beweidingsbehandeling het nie die oorlewing of die verspreiding van die peulgewasse merkwaardig beihvloed nie hoewel die verskyning van Sporobolus pyramidalis as ’n ongewenste gras verhoog is deur beweiding gedurende die reënseisoen. Op kleigrond het dit gepaard gegaan met ‘n vermindering van Hyparrhenia spp.

Na moontlike tekortkominge en die toepaslikheid van die tipe ondersoek en proef is bespreek.