Comparison of wild mustard species and green beans for leaf number during tongue cultivation and intercropping at two sites (Umbumbulu and Ukulinga). Comparison of wild mustard species and green beans for plant height during tongue cultivation and intercropping on two sites (Umbumbulu and Ukulinga) with (+) or without (-) organic fertilization. Comparison of wild mustard species and green beans for biomass during tongue cultivation and intercropping at two sites (Umbumbulu and Ukulinga) with (+) or without (-) organic fertilization.
Comparison of wild mustard species for fresh biomass six weeks after sowing under sole crops and intercropping with green beans at two sites (Umbumbulu and Ukulinga). Comparison of wild mustard - green bean polycultures (species K or M or 1 mixed with green beans) for soil equivalent conditions during autumn, winter, spring and summer production at two sites (Ukulinga and Umbumbulu).
INTRODUCTION
Literature Review
Wild mustard (Brassica spp.), is one of the wild vegetable species in rural southern Africa. The present study investigated the effect of three species of wild mustard (specia brascica) and polyculture of green bean (Phaseolus vulgaris) on plant development and yield of component crops under field conditions in two areas during four normal seasons of the year (autumn, winter, spring and summer). Morphological appearance of three types of wild mustard (I, M and K) in the vegetative stage of development approximately four weeks after emergence.
Note that the cropping system treatments compared were: sole cultivation = green bean monoculture and interculture, GB/I or /M or /K when green beans were intercropped with wild mustard species I or M or K. Comparison of wild mustard - green bean polycultures (species K or M or I mixed with green beans) for soil equivalent conditions during autumn, winter, spring and summer production at two sites (Ukulinga and Umbumbulu). There was overall significant (P Comparison of wild mustard and green beans for economic yield six weeks after sowing in tongue and intercropping system. Polyculture was found to be generally associated with better yield of green bean pods in all seasons except winter (data not shown). These results indicated that polyculture can have a beneficial effect on the harvest index of green beans, which is consistent with the observation that green beans grew taller in tongue culture than in polyculture (Figure 2.7). Therefore, interplanting green beans and wild mustard has a significant advantage for the small farmer who has limited production land. It is difficult to conclude from this study that the association between green beans, a legume with potential for nitrogen fixation, and wild mustard could have benefited the latter nutritionally. The results of an overall better yield of green beans (Figure 2.12) under polyculture showed that dry matter accumulation in green beans was not suppressed by wild mustard in a polyculture. A study of the soil nutrition aspect of the reported intercropping system with green beans and wild mustard has been reported in chapter three of this thesis. Wild mustard intercrops yielded higher gross income (Figure 2.13) than their single crops of either wild mustard species. However, legume sole crops yielded more gross economic income than both intercrops and wild mustard sole crops due to higher economic value (cash value per kg) compared to one kg of wild mustard. During the winter, legumes performed poorly and affected the overall gross income of the intercropping system. Despite the fact that heavy green bean crops yielded more gross incomes than intermediate crops, wild mustard intercropping is proving a viable option over heavy mustard crops. It would be expected that the sales value of organically produced mustard and green beans would be higher than the sales value shown in Figure 2.13 when conventional vegetable price list was used. Overall, the catch crop appears to provide a greater economic benefit than growing a single crop of wild mustard, but only by looking at output values. This study aimed to evaluate soil nutrient dynamics within the root zones of wild mustard and green beans during four seasons of the year in response to organic fertilization. For each crop treatment (see section 2.2 for the list of treatments), soil samples were taken from the top 10-15 cm of the soil in the root zone, in the flowering phase (42 days after sowing) of the wild mustard. The mineral content of selected macroelements (Ca, Mg, K and P) showed a variable pattern between fertilized and unfertilized wild mustard varieties for all treatments. For microelements (Zn, Mn, Cu and Fe), there was a general trend of increasing plant mineral content with intercropping in fertilized treatments for all types of wild mustard, while a variable pattern was observed in unfertilized treatments (Figure 3.4). Copper showed greater accumulation with catch crops in fertilized treatments for all three wild mustard species (Figure 3.4). Comparison between intercrops and individual crops of three types of wild mustard (I, K and M) in fertilized and unfertilized treatments for Ca, Mg, K and P. Comparison between intercrops and individual crops of three types of wild mustard (I, K and M) in fertilized and unfertilized treatments for Zn, Mn, Cu and Fe. Compared to monoculture, intercropping generally showed reductions in N, Ca, Mg, and K in fertilized and unfertilized treatments of broad bean intercropped with any of the three wild mustard species (Figure 3.5). The concentration of nitrogen in green beans was higher in intercropping than in leaf cultivation in all three wild types of mustard in fertilized treatments by 17.7% in types I, K and M (Figure 3.7). Intercropping reduced protein content in wild mustard plants by 6.1% and 23.9% in species I and K respectively in fertilized treatments while 7% protein reduction was observed for species I, K and M respectively in unfertilized treatments ( Figure 3.8). Magnesium, Cu and Mn showed a general decreasing trend in the soil during the study, suggesting that wild mustard may have absorbed a lot of these elements. Intercropping reduced the accumulation of protein content in wild mustard leaves in all species in both fertilized and unfertilized treatments (Figure 3.8). We could therefore conclude from these results that interculture reduces the protein content in the leaves of wild mustard for all three species. These results surprisingly suggest that fertilization may have reduced protein accumulation in wild mustard leaves. The aim of this study was to determine the effects of origin and season on the production and seed quality of wild mustard seeds. Species M had higher (P < 0.05) yields than both species I and K across seasons at the two sites. Comparison of seed yield of three wild mustard varieties (inset) during three seasons at the two locations. There were no significant differences between species in terms of IOOO seed weight (Figure 4.2). However, there was a significant difference (P <0.05) between species for 100-pod seed weight at both sites (Figure 4.3). Comparison of three species of wild mustard (inset) for pod weight of 100 pods at both sites. Seed germination of three wild mustard species (inset) harvested from intercropping and self-cropping systems. Germination of seeds of three wild mustard species (inset) in three seasons at two locations. K-type seeds grown in Umbumbulu in winter had a low germination percentage than seeds grown in autumn and spring (Figure 4.5). At Umbumbulu, there were no significant differences between seeds of the M species produced during the three seasons, with a germination capacity of ~. The results of this study showed that the highest seed yield for wild mustard was obtained during the winter season. The results also showed that the difference in seed yield was due to the growth habit of wild mustard. For seed production, this study found winter to be the best season for wild mustard. Further investigation of aspects of seed quality (other than germination) of wild mustard relative to production seasons is needed. This study showed that organic fertilization improved the vegetative growth of both wild mustard and green bean. The results of the soil analysis showed that the balance of some mineral elements in the root zone is positively affected by the presence of wild mustard. The positive effects suggest that wild mustard may have the ability to improve mineral availability. It is therefore recommended that further investigations be undertaken into the role of wild mustard in soil quality. This fertilizer application increased biomass at all sites and suggests that the species and their companion crops in the polyculture require additional fertilization and that the effect of wild mustard on increasing soil mineral nutrients may not be sufficient to recommend no fertilizer application. However, based on the results of non-fertilized treatment, it can be concluded that wild mustard will grow with a low nutrient value of the soil. The results of this study showed increased Mg, Zn, Ca and K in intercropped wild mustard. In conclusion, this study showed that wild mustard and green beans were compatible in polyculture. Although spring and fall crops produced the highest yields of vegetative material, it is clear that wild mustard can be grown year-round. The main objective of this study was to determine the intercropping compatibility of wild mustard and green beans and to gain insight into the understanding of soil nutrient dynamics in a wild mustard/green bean polyculture, with or without organic fertilization. Note that the analysis shows 9 df for cultivation system as . in a crop analysis. . takes into account the component cropping system for the purposes of data collection and a) Autumn. Note that the analysis shows 9 cif for cropping system, which takes into account the component crops of an intercropping system for the purpose of data collection and analysis. Analysis of variance for plant biomass 42 weeks after sowing at the two sites (Ukulinga and Umbumbulu). 1 Analysis of variance for selected mineral elements 42 days after planting during autumn, winter, spring and summer at Ukulinga and Umbumbulu.
Discussion
SOIL NUTRIENT DYNAMICS IN WILD MUSTARD-GREEN BEANPOLYCULTURE
SEED PRODUCTION AND GERMINATION CAPACITY
GENERAL DISCUSSION AND CONCLUSIONS
Locations of the research sites (red dots), Umbumbulu and Ukulinga (Ukulinga is in Pietermaritzburg)
