Family ministry in a postmodern church

This article is a revised version of aspects of the PhD thesis of Dr Thinus van Staden with Prof. Yolanda Dreyer as promoter.The aim of the article is to reflect on the necessity for family ministry in the church today, and to explore different models and methods for doing it. This article must be understood against the backdrop of the challenges facing mainline churches, of which the decline in numbers, the lack of support for programmes and initiatives on behalf of families, and the apparent inability to minister effectively to young people, are the most pressing. Since the early church there has been a close relationship between church and home. Not only did rituals and liturgies spill from the gathered congregation into homes; metaphors from family life also provided images and language to the early church. In the last few decades there has been a rekindled interest in the home as the primary incubator for faith formation. Several books, articles, organisations, programs, consultants and churches have described their approach as ‘family ministry’. From a practical-theological viewpoint, there must be a set of criteria by which these approaches could be evaluated. This article aims to contribute in this regard, and to critique different approaches to family ministry.http://www.hts.org.zaam201

Biblical perspectives on family ministry in a postmodern church

The aim of the article is to reflect on biblical-theological perspectives on family in order to enrich postmodern faith communities. In the post-biblical period the biological family was central to the process of the institutionalisation of the church and the spiritual aspect of family was underplayed. The church father, Augustine, indowed marriage with sacramental status. This emphasised the presence of God in the family, but ‘procreation’ dominated his theology of marriage. The sacramental status of marriage along with the dominance of patriarchy made marriage indisputable. This obstructed any possibility of thinking creatively about marriage in a postmodern context. In his reformation of marriage Martin Luther succeeded in deconstructing the sacramental status of marriage, but did not succeed in overturning patriarchal dominance. The reality of postmodern families differs vastly from that of biblical times and the times of Augustine, Aquinas and Luther. The challenge of the church in a postmodern world is to reflect in a responsible biblical theological way on the relationship between adults and children from the perspective of the kingdom of God. This article aims to contribute in this regard.This article represents a reworked version of aspects from the PhD dissertation (University of Pretoria) with Prof. Dr Yolanda Dreyer as supervisor. (http://hdl.handle.net/2263/40208)Hierdie artikel is ’n verwerkte weergawe van aspekte van die PhD-verhandeling van J.M.v.S. (Universiteit van Pretoria), met Y.D. (Universiteit van Pretoria) as promotor. (http://hdl.handle.net/2263/40208)http://www.hts.org.zaam201

Photosynthesis rate, radiation and water use efficiencies of irrigated potato in a semi-arid climate using Eddy covariance techniques

Understanding the photosynthetic behaviour, radiation use efficiency (RUE) and water use efficiency (WUE) of potatoes in response to diurnal and seasonal fluctuations in weather, is important for optimizing growth and production. The net ecosystem exchange (NEE) of carbon dioxide (CO2), is a parameter used to measure the balance between gross CO2 assimilation (also referred to as gross primary production (GPP)) and ecosystem respiration (Reco). The objectives of this study were (i) to quantify the NEE of potato grown in two contrasting agro-ecologies and partition NEE into Reco and GPP; (ii) to describe seasonal patterns in daily photosynthesis, RUE and WUE in potato; and (iii) to analyse the variability in photosynthesis rate, RUE and WUE as affected by weather and crop growth stage. We measured CO2 and water vapour fluxes using eddy covariance techniques in potato fields in two production regions of South Africa. The winter crop had higher mean RUE and WUE values, whereas the summer crop absorbed more CO2. RUE had a negative relationship with incident radiation. To optimize dry matter production, WUE and RUE, potato crops must be well established and develop a full canopy early during the season. Maintaining the crop for a longer period in the field has yield benefits, although they appear to decline over time due to reduced efficiencies as the crop matures. The RUE observed over the growing period in the present study was high, relative to findings by other field studies, despite relatively warm growing conditions that were likely sub-optimal for potato.Potatoes South Africa.http://journals.cambridge.org/action/displayJournal?jid=AGSPlant Production and Soil Scienc

Determination of crop coefficients and evapotranspiration of potato in a semi-arid climate using canopy state variables and satellite-based NDVI

This article belongs to the Special Issue titled 'Remote Sensing for Irrigation and Water Management in Agriculture'.Estimating crop coefficients and evapotranspiration (ET) accurately is crucial for optimizing irrigation. Remote sensing techniques using green canopy cover, leaf area index (LAI), and normalized difference vegetation index (NDVI) have been applied to estimate basal crop coefficients (Kcb) and ET for different crops. However, analysis of the potential of these techniques to improve water management in irrigated potato (Solanum tuberosum L.) is still lacking. This study aimed to assess the modified nonlinear relationship between LAI, Kcb and NDVI in estimating crop coefficients (Kc) and ET of potato. Moreover, Kc and ET were derived from the measured fraction of green canopy cover (FGCC) and the FAO-56 approach. ET estimated from the FAO-56, FGCC and NDVI approaches were compared with the ET simulated using the LINTUL-Potato model. The results showed that the Kc values based on FGCC and NDVI were on average 0.16 lower than values based on FAO-56 Kc during the mid-season growing stage. ET estimated from FAO-56, FGCC and NDVI compared well with ET calculated by the LINTUL-Potato model, with RMSE values of 0.83, 0.79, and 0.78 mm day−1 , respectively. These results indicate that dynamic crop coefficients and potato ET can be estimated from canopy cover and NDVI. The outcomes of this study will assist potato growers in determining crop water requirements using real-time ETo, canopy state variables and NDVI data from satellite images.Potatoes South Africa.https://www.mdpi.com/journal/remotesensingPlant Production and Soil SciencePlant ScienceSDG-02:Zero HungerSDG-12:Responsible consumption and productio

Potato crop response to genotype and environment in a subtropical highland agro-ecology

Potato response to environment, planting date and genotype was studied for different agro-ecological zones in Lesotho. Field experiments were conducted at four different sites with altitudes ranging from 1,655 to 2,250 m above sea level during the 2010/2011 and 2011/2012 summer growing seasons. Treatments consisted of three cultivars that varied in maturity type, two planting dates and four sites differing in altitude and weather patterns. Various plant parts were measured periodically. To understand and quantify the influence of abiotic factors that determine and limit yields, the LINTUL crop growth model was employed which simulated potential yields for the different agro-ecological zones using weather data collected per site during the study period. Observed actual crop yields were compared with model simulations to determine the yield gap. Model simulations helped to improve our understanding of yield limitations to further expand potato production in subtropical highlands, with emphasis on increasing production through increased yields rather than increased area. Substantial variation in yield between planting date, cultivar and site were observed. Average tuber dry matter (DM) yields for the highest yielding season were above 7.5 t DM ha−1 or over 37.5 t ha−1 fresh tuber yield. The lowest yield obtained was 2.39 t DM ha−1 or 12 t ha−1 fresh tuber yield for cultivar Vanderplank in the 2011/2012 growing season at the site with the lowest altitude. Modelled potential tuber yields were 9–14 t DM ha−1 or 45–70 t ha−1 fresh yield. Drought stress frequently resulted in lower radiation use efficiencies and to a lesser degree harvest indices, which reduced tuber yield. The site with the lowest altitude and highest temperatures had the lowest yields, while the site with the highest altitude had the highest yields. Later maturing cultivars yielded more than earlier maturing ones at all sites. It is concluded that the risk of low yields in rain-fed subtropical highlands can be minimised by planting late cultivars at the highest areas possible as early as the risks of late frosts permit.http://link.springer.com/journal/11540hb201

Climate change and potato production in contrasting South African agro-ecosystems 2 : Assessing risks and opportunities of adaptation strategies

This study aims to assess the risks and opportunities posed by climate change to potato growers in South Africa and to evaluate adaptation measures in the form of changes in planting time growers could adopt to optimise land and water use efficiencies in potato, using a climate model of past, present-day and future climate over southern Africa and the LINTUL crop growth model. This was done for distinct agro-ecosystems in South Africa: the southern Mediterranean area where potato still is grown year round with a doubling of the number of hot days between 1960 and 2050, the Eastern Free State with summer crops only and Limpopo with currently autumn, winter and spring crops where the number of hot days increases sevenfold and in future the crop will mainly be grown in winter. A benefit here will be a drastic reduction of frost days from 0.9 days per winter to 0. Potato crops in the agroecosystems will benefit considerably from increased CO2 levels such as increased tuber yield and reduced water use by the crop, if planting is shifted to appropriate times of the year. When the crop is grown in hot periods, however, these benefits are counteracted by an increased incidence of heat stress and increased evapotranspiration, leading in some instances to considerably lower yields and water use efficiencies. Therefore year-round total production at the Sandveld stabilizes at around 140 Mgha−1 (yield reduction in summer and yield increase in winter), increases by about 30% in the Free State and stays at about 95 tha−1 at Limpopo where yieldPotatoes South Africa and the Netherlands Ministry of Economy, Agriculture and Innovation Agriculturehttp://link.springer.com/journal/11540hb201

The effect of drought stress on yield, leaf gaseous exchange and chlorophyll fluorescence of dry beans (Phaseolus vulgaris L.)

Global food production relies on irrigation, especially in low rainfall areas such as South Africa. The study was conducted to determine the effect of drought stress on growth, yield, leaf gaseous exchange and chlorophyll fluorescence parameters of dry bean under field conditions and the after effects of drought stress upon lifting drought stress. A rain shelter field trial was conducted at the Hatfield Experimental Farm of the University of Pretoria, Pretoria, South Africa. Dry bean cultivar DBS 360 was subjected to five levels of moisture stress arranged in a randomized complete block design with six replications. The plants were exposed to the following drought stress levels: the control: Irrigated to field capacity (S1), Withholding irrigation from 36 days after planting (DAP) for 24 days (S2), Withholding irrigation from 49 DAP for 24 days (S3), Withholding irrigation from 73 DAP to the end of the growing season (S4) and irrigated to field capacity on a fortnightly bases for the rest of the season from 36 DAP to the end of the growing season (S5).The results revealed that drought stress reduced dry matter production, leaf area index, number of pods per plant, number of seeds per plant, hundred seed weight and grain yield. Treatments S1, S4 and S5 produced statistically similar grain yield. Drought stress towards the end of the growing season may not cause serious harm in grain yield. Drought stress resulted in a reduction in photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance and transpiration. Chlorophyll fluorescence was also affected by drought stress. The highest WUE was found in the treatment which was irrigated on fortnightly bases from 36 DAP. This indicates that with appropriate irrigation it is possible to save water without a great yield loss in dry bean.http://www.elsevier.com/locate/agwat2018-01-31hb2017Plant Production and Soil Scienc

Growth and yield responses of commercial sugarcane cultivars to mulching in the coastal rainfed region of South Africa

The perceived negative cultivar responses to mulching has limited the adoption of this practice in the South African sugarcane industry. This study was aimed at evaluating cane yield and quality responses and population dynamics of popular cultivars to mulching in the rainfed region of South Africa. A four-replicate field trial was established using a strip-plot design. Cane and tonnes estimated recoverable crystal yields (TERC) yields, and yield components were determined in three summer ratoons and one winter ratoon. In-season soil water and temperature were monitored. Mulching significantly improved cane and TERC of all cultivars across ratoons. The highest improvements in cane and TERC were 85% (N45) and 92% (N39), respectively. The improvements were attributed to the higher soil water content under the mulch blanket. Stalk height, mass and population (winter ratoon) were improved at harvest for most cultivars across ratoons with mulching. Mulching reduced emergence and tillering presumably due to lower soil temperatures under the mulch blanket. The highest mulch-yielding cultivars were N47 and N42, for which yield increased by 15 and 13 t ha−1, respectively. Mulching was beneficial for sugarcane production, regardless of the cultivar and ratooning season, and can be recommended for all current cultivars in the coastal rainfed region.http://www.tandfonline.com/loi/tjps202018-02-27hb2016Plant Production and Soil Scienc

Yield decline in mechanically harvested clonal tea (Camellia sinensis (L) O. Kuntze) as influenced by changes in source/sink and radiation interception dynamics in the canopy

High labour costs and shortages and the cost of production has resulted in tea (Camellia sinensis (L)O. Kuntze) industries in central and southern Africa becoming unprofitable. This has led to the fullmechanization of shoot harvesting, however, a reduction in yield has been observed with mechani-cal harvesting. It was hypothesized that the decline in yield as a result of mechanical harvesting is aresult of the indiscriminate harvesting of shoots which leads to a change in sink/source and radiationinterception dynamics within the canopy. As a result whole plant photosynthesis is impacted; whichultimately impacts tea bush productivity. Studies conducted at Tingamira estate, Chipinge, Zimbabweshowed significant yield differences between hand plucking and machine harvesting treatments, withhigher yields under hand plucking across all seasons (43 945 kg green leaf ha−1) as compared to hand-held(35 114 kg green leaf ha−1) and ride-on machines (36 268 kg green leaf ha−1) (p < 0.05). This reduction inyield was associated with a decrease in both the number and mass of desirable shoots over each season.The cause of this change was largely attributed to the indiscriminate removal of foliage by the machineswhich resulted in the proliferation of immature shoots, with an associated increase in sink strengthand competition for available photo-assimilates. In addition, the depletion of the maintenance layer inmechanically harvested bushes, as indicated by reduced fractional interception of photosyntheticallyactive radiation in the top 10 cm in these bushes and reduced photosynthetic rates in these bushes, sug-gests that these bushes were also source limited, as compared to hand plucked bushes. Therefore thechanges in tea bush architecture, as a result of mechanical harvesting, resulted in changes in sink/sourcedynamics which led to a proliferation of immature shoots which competed for limited photo-assimilates.Tea Research Foundation of CentralAfrica for the study leave, Tanganda Tea Company, Tingamira estatefor hosting the trials and SABINA and POL/SABINA.http://www.elsevier.com/locate/scihorti2016-10-31hb201

Irrigation amounts affect the compositional changes of Moringa oleifera seeds throughout different developmental stages

The compositional development of Moringa oleifera seed across a range of growth stages was monitored at three irrigation treatments, simulating total annual rainfall of 900 mm, 600 mm and 300 mm/annum over two consecutive growing seasons (24 months). Fruit developmental stages were categorized according to fruit diameter (0 mm – 28 mm) at 2 mm increments. Starch was the first to accumulate during the initial histo-differentiation phase (fruit diameters of 0 mm-12 mm), while oil levels remained comparatively low. During the subsequent expansion phase (fruit diameters of 12 mm – 24 mm) however, stored starch was mobilized and used in oil biosynthesis, reducing the starch content. The bulk of oil and protein were synthesised throughout this phase with their content increasing sigmoidally. As the seed moisture content decreased during the final maturation phase (fruit diameters of 24 mm – 28 mm), the average oil content reached 24.8%, while the protein contents were 24.8% and the starch contents were 8.7%. The different irrigation treatments had less of an effect on the final starch, oil and protein content than on the time and rate of their synthesis throughout seed development. Higher irrigation levels principally favoured oil biosynthesis. The highest final oil contents were measured at the intermediate irrigation treatment (600 mm/annum), suggesting that both lower and higher irrigation levels could possibly reduce final oil contents. The reduction in irrigation amount delayed the onset of oil biosynthesis and as a result the starch content reached higher levels prior to its remobilization during oil biosynthesis.© 2014 Friends Science Publishershttp://www.fspublishers.orgam201