Smuts finger grass (Digitaria eriantha Cv Irene) root growth assessment and some physicochemical characteristics on coal mined land compacted soil

The coal mine soil layers contained high values of bulk density of 1.80gcm-3 and 1.90gcm-3 at depths of 0-20 and 20-40 cm respectively, low contents of organic matter, soil pH and soil nutrients concentration. A field trial was conducted to investigate root growth responses of Smuts Finger grass (Digitaria eriantha cv Irene) to compacted mine soil layers. It was revealed that the greatest root masses were noted in the upper horizons with progressively significantly less in the deeper horizons. Roots of this species penetrated compacted soil layers and decreased soil bulk density. The highest soil pH values were found in the upper layers with greatest root biomass. Soil nutrients (P, Mg, Ca, Na and K) status was also better in the upper layers. Smuts Finger grass could be used as an alternative method for rehabilitation of compacted mine soil layers.Keywords: Coal mine soil; Smuts Finger grass; Soil bulk density; Soil pH; Soil nutrient

Community gardens as a strategy for coping with climate shocks in Bikita District, Masvingo, Zimbabwe

Drought is the most important climate shock affecting rural farmers this century. In a bid to reduce the effects of climate shocks, coping strategies are being investigated. Community gardens is one such strategy. The purpose of the study was to objectively look at the dynamics involved in community gardens, that is, the significance the gardens have on poverty, food security and income of rural farmers. The study was carried out in Bikita District, Masvingo Province, Zimbabwe. Rural farmers in this area have been hit hard by drought and the effect climate change has had on agricultural production. The main findings of the study showed that community garden participants are mainly women. Many farmers expressed ignorance on the existence and risks associated with climate shocks but agreed that temperatures have increased and rainfall has decreased in the past decade. Several farmers indicated that they do not acquire income from sale of their crops and vegetables, as most are used for household consumption. However, those getting an income use it for basic necessities, children’s education and maintaining their farm business. Although there were some constraints, water insufficiency being the largest, community gardens provided many benefits, including social, economic and environmental benefits.Keywords: Community gardens, climate shocks, food security, adaptation, vulnerability, drought, extension service

Evaluation of pulp and paper making characteristics of elephant grass (Pennisetum purpureum Schum) and switchgrass (Panicum virgatum L.)

Shortage of conventional raw material for the pulp and paper products together with the increasing world demand for paper has renewed interest in non-wood fibres. Non-wood pulping capacity has been increasing steadily over the last decade. A lot of crops grown for biomass, like switchgrass (Panicum virgatum L.), are good examples of plants with potential for pulp production. Raw material chemical composition, kraft pulp yield and properties, and fibre characteristics of elephant grass or hybrid pennisetum (Pennisetum purpureum Schum. cv. SDPN3) and switchgrass (cv. Cave-in-Rock) were determined in an effort to evaluate them as raw materials for pulp and paper production. Elephant grass had α-cellulose and Klasson lignin contents of 45.6 and 17.7%, respectively. The respective values for switchgrass were 41.2 and 23.89 %. Pulp yields, following a mild kraft process, were 48 and 50% for switchgrass and elephant grass, respectively. The corresponding kappa numbers were 15.5 and 9.2. The weight-weighted fibre length averaged 1.32 mm. Pulp freeness was higher for switchgrass (330 mL) than for elephant grass (139 mL). Elephant grass had a burst index above 5.85 kP.m2 g-1. These characteristics demonstrate the suitability of both elephant grass and switchgrass for pulp production.Key words: Grass pulp, kraft pulping, non-wood fibre, elephant grass, switchgrass

Production of rape (Brassica napus L.) on soils amended with leguminous tree prunings : yield responses in relation to the chemical composition of the tree prunings

Leguminous tree leaf litter has potential as a nutrient source for smallholder vegetable production systems. However, quality of the leaf litter influences yield responses by the crops grown. Comparative yield responses of rape (Brassica napus L.) to legume prunings of different chemical composition were evaluated in a three block randomized complete block design (RCBD) field experiment. Prunings of Leucaena leucocephala, Calliandra calothyrsus, Acacia angustissima and Acacia karoo were applied to the soil at 5 t ha-1. Two controls, 0 N and mineral N applied at 150 kg N ha-1, were used. Total biomass, leaf number and size, and area were measured over a 9 week period after transplanting. The mean total biomass yields following amelioration with the various prunings ranged from 2.56 to 11.12 t DM ha-1. The mean saleable leaf harvests ha-1 were 10.04, 7.56, 5.02, 3.00, 1.28 and 0.86 t for 150 N, L. leucocephala, A. angustissima, C. calothyrsus, A. karoo and 0 N, respectively. These results were corroborated by the resource quality of the respective organic ameliorants. The results indicated that biomass transfer technology could be used as an alternative to mineral fertilizers for vegetable production and that yields were dependent on resource quality of prunings.http://www.academicjournals.org/AJAR/index.htmam201

Weed species composition and density under conservation agriculture with varying fertiliser rate

Conservation agriculture (CA) is a sustainable management system that optimises yield while reducing input costs. However, reduction in tillage intensity and frequency as practised under CA generally alters weed densities and composition. The objective of the study was to evaluate the effect of tillage, cropping system and fertiliser rate on weed density and diversity under CA systems compared with conventional tillage (CT). An on-station field trial with a split-plot, randomised complete block design, was used and included two tillage systems, three cropping systems and two fertiliser levels. Reduced tillage had significantly (p < 0.05) higher weed density (42 m−2) but lower weed biomass (154 g m−2) in contrast to CT with lower weed density (36 m−2) and higher weed biomass (242 g m−2). In a principal component analysis ordination, Datura ferox and Tribulus terrestris were more strongly associated with high fertiliser rate, whereas Zinnia peruviana was associated with CT. The increase in weed density and diversity under reduced tillage is likely to restrain the adoption of CA. Therefore, there is a need for alternative weed management options depending upon the weed spectrum, cropping system and fertiliser management.The ARC–Institute for Climate, Soil and Water, the Maize Trust and University of Pretoria .http://www.tandfonline.com/loi/tjps202019-04-13hj2018Plant Production and Soil Scienc

Nutritive value of grasses in semi-arid rangelands of Ethiopia : local experience based herbage preference evaluation versus laboratory analysis

We examined the nutritive value of common grass species in the semi-arid rangelands of Borana in southern Ethiopia using local experience based herbage preference (LEBHP) perception and laboratory techniques. Local pastoralists in the study area were asked to identify common grass species and rank them according to the species’ preferences and palatability to cattle. The pastoralists listed a total of 15 common grass species which were then sampled during the main rain and cold dry seasons and analyzed for crude protein (CP), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF) and ash content to verify pastoralists’ claim regarding the quality of individual species. The relative feed value (RFV) and dry matter digestibility (DMD) were also calculated using NDF and ADF contents. Spearman’s rank correlation was used to examine possible relationships between laboratory results and pastoralists’ experience on grass quality. Cenchrus ciliaris, Chrysopogon aucheri, Digitaria milanjiana, Eragrostis papposa and Panicum maximum were the top five species based on LEBHP perception. There were indications of inconsistency in terms of LEBHP perception among the different pastoral communities. The chemical composition of all grass species showed significant (p<0.05) variation between sites, seasons and species. The results showed that the CP values for the Borana rangelands were in the range of 8.7% in the main rain season to 5.1% for the cold dry season. The fiber constituents were relatively low in the main rain season compared to the cold dry season. Overall, Digitaria milanjiana had the highest CP (16.5%) content, while the least was recorded with Heteropogon contortus (10.8) and Aristida adoensis (9.8%) during the main rain season. It seems that the spatial variability of landscapes within the wider geographical regions, soil properties and texture, and land-use patterns probably contributed to site differences in species quality. Generally, the RFV of individual grass species was significantly (p<0.05) varied between and within sites. The ranking of species by pastoralists according to their preferences by cattle was highly correlated with the chemical composition of laboratory results of individual grass species with ‘r’ values for CP (0.94), ash (0.95), NDF (-0.98), ADF (-0.93) and ADL (-0.93). We suggest the complimentary use of LEBHP and laboratory techniques in evaluating the nutritive quality of rangeland forage species for sustainable animal production.The Federal Democratic Republic of Ethiopia, Ministry of Agriculture through Rural Capacity Building Project (RCBP)http://www.ajas.infoam201

The impact of tillage system and herbicides on weed density, diversity and yield of cotton (Gossipium hirsutum L.) and maize (Zea mays L.) under the smallholder sector

The study was carried out to evaluate the impact of tillage system in combination with different herbicides on weed density, diversity, crop growth and yields on 18 farms in Kadoma, Zimbabwe. Experiments were set up as a split plot design with three replications on each farm. Tillage was the main plot (Conservation Tillage (CT), Conventional Tillage (CONV)) and weeding option (hand weeding, cyanazine, atrazine, glyphosate only and mixture of cyanazine + alachlor and atrazine + alachlor) as the sub-plots. Due to the heterogeneous nature of farmers' resource base, the farms were grouped into three farm types: high (Type 1), medium (Type 2) and poorly resourced farmers (Type 3). The hand hoe weeded treatments had 49 percent higher total weed densities in CT relative to CONV, and was statistically similar to the glyphosate treatment. The mixed pre-emergence herbicides reduced the diversity indices by 69 and 70 percent when compared to the hand hoe weeded treatment under CT in cotton and maize, respectively. The effectiveness of all pre-emergence herbicides were not influenced by tillage but were affected by farmers resource endowments with pronounced effect in Farm Type 1. Maximum plant heights of 85 and 238 cm were recorded for mixed pre-emergence herbicides under CT for cotton and maize, respectively. Minimum plant heights of 75 and 217 cm were recorded for the respective hand hoe weeded treatments. The hand hoe weeded treatments resulted in average cotton lint yield of 1497 and 2018 kg ha−1 for maize. The mixed pre-emergence herbicides treatments gave yields of 2138 and 2356 kg ha−1 of cotton and maize, respectively. The higher weed densities in CT under hand weeded treatments underscored the need for other weeding options. Similarly, a mixture of cyanazine + alachlor in cotton and atrazine + alachlor in maize is recommended for suppressing broad and grass weed populations and enhancing yields in CT systems

Manure from cattle as fertilizer for soil fertility and growth characteristics of Tall Fescue (Festuca arundinacea) and Smuts Finger grass (Digitaria eriantha)

Applying cattle manure to soil in optimum rates can enhance soil fertility and plant growth. The objectives of this study were to investigate the influence of different rates of cattle manure application on soil fertility and the growth and productivity of Tall Fescue (Festuca arundinaceae) and Smuts Finger grass (Digitaria eriantha), two popular pasture species in South Africa. These field trials were established on a uniform sandy clay loam (Hutton) soil on the Hatfield Experimental Farm, of the University of Pretoria in Pretoria. There were five treatments comprising five rates of cattle manure incorporation (0, 20, 40, 80 and 120 tonnes/ha). During the growing season, Tall Fescue plants from cattle manure-amended plots were significantly taller in the 80 tonnes/ha treatment, while Smuts Finger grass reached the maximum height in the 40 tonnes/ha treatment.Coaltech 2020http://www.lrrd.orghb201

Is the soil seed bank a reliable source for passive restoration of bush-cleared semi-arid rangelands of South Africa?

BACKGROUND : Bush clearing of encroached rangelands is crucial for restoration of herbaceous cover and diversity. Regeneration after bush clearing depends largely on the soil seed bank (SSB) size and composition. To assess the potential of the SSB to facilitate post-clearing herbaceous restoration, we examined the SSB density, composition and diversity and similarity between SSB and aboveground vegetation (AGV). METHODS : The study was conducted in semi-arid rangelands of Maseding and Kgomokgomo in North-West Province of South Africa. In each rangeland, all woody plants in three 1250 m2 plots were cut using saws and loppers, with the stumps treated with picloram. Paired observations were conducted in cleared and uncleared microsites. Soil samples were collected at three depths (0–10, 10–20 and 20–30 cm) in each microsite in April (pretreatment), August, October and December 2016 and in April and August 2017. SSB was assessed using seedling emergence method, whereas pre- and post-clearing surveys of AGV were conducted in February 2016 and 2017, respectively. RESULTS : Cleared microsites had significantly (p < 0.01) higher seed bank densities (1872 and 693 seeds m-2 at Maseding and Kgomokgomo, respectively) relative to uncleared microsites in August 2017, with grasses accounting for higher densities than other plant functional groups in the upper 0–10 cm. Pioneer grasses (Aristida congesta subsp. barbicollis, Brachiaria eruciformis and Tragus berteronianus) and invasive forbs (Bidens pilosa and Schkuhria pinnata) dominated the SSB in cleared microsites at Maseding, whereas succulents (Portulaca spp.) and pioneer grasses (T. berteronianus and Urochloa mosambicensis) were abundant at Kgomokgomo in August 2017. SSB and AGV were dissimilar until December 2016; thereafter, similarity increased significantly (p < 0.05) in cleared microsites (Sørensen’s coefficient = 0.60 to 0.66 at Maseding and 0.43 to 0.52 at Kgomokgomo) compared to uncleared microsites. Species diversity was highest in August 2016 and April 2017 at Maseding, but it did not differ between two microsites (p > 0.05). At Kgomokgomo, SSB was more diverse in cleared than uncleared microsites in April and August 2017. CONCLUSION : High seed bank densities in the upper soil layer in cleared microsites would promote passive restoration, but regeneration is likely to be initiated by early successional species. However, close monitoring and eradication of invasive forbs and succulents is necessary following bush clearing. The tendency of SSB resembling AGV over time in cleared microsites signifies that seed production from AGV is important for passive restoration following bush clearing.Fig. S1. A diagram showing the layout of the experiment and the distribution of plots at Maseding and Kgomokgomo rangelands. The small white shaded squares are 1.7-m2 quadrats used for herbaceous vegetation assessment. Table S1. Species abundance (%) of the AGV during pre-treatment (PTT) in 2016 and in cleared and uncleared microsites in 2017 at Maseding. Table S2. Species abundance (%) of the AGV during pre-treatment (PTT) in 2016 and in cleared and uncleared microsites in 2017 at KgomokgomoThe Agricultural Research Council (MMN 3014) and National Research Foundation (NRF) of South Africa.https://ecologicalprocesses.springeropen.comam2020Plant Production and Soil Scienc

Factors affecting the choice of conservation agriculture practices adopted in smallholder cotton farmers in Zimbabwe

Conservation agriculture (CA) has been widely promoted in Zimbabwe as an antidote to non-viable agricultural production and continual land degradation. However, the adoption process had been quite slow and has not yet entered into the exponential uptake phase. This study aimed at identifying factors that influence the level of adoption of CA components. A cluster analysis from results of a household survey administered to 146 households in Muzvezve II, Kadoma District, Zimbabwe identified five dominant CA strategies (clusters) practiced by cotton growing farmers. A multinomial logit model revealed that the choice of CA components adopted is positively influenced by farmer’s age, formal education, access to extension services, labour, animal draught power availability and land size. The empirical results suggests that, to promote adoption of a complete package of CA policies that increase access to formal education and extension of CA should make strategic intervention through innovative methods of farmer to farmer extension services. Promotion of longer-term and effective CA can only be accomplished through targeting young educated farmers. It is of paramount importance as well to address the main factors leading to non-adoption and slow adoption such as labour and animal draught power availability.The National Research Foundation (NRF) of South Africa and International Foundation of Science (IFS), Food and Agriculture Organization of the United Nations (FAO), through Union Project in Zimbabwe.http://www.academicjournals.org/AJARam201