Exploring Niches for Short-Season Grain Legumes in Semi-Arid Eastern Kenya — Coping with the Impacts of Climate Variability

Climate variability is the major risk to agricultural production in semi-arid agroecosystems and the key challenge to sustain farm livelihoods for the 500 million people who inhabit these areas worldwide. Short-season grain legumes have great potential to address this challenge and help to design more resilient and productive farming systems. However, grain legumes display a great diversity and differ widely in growth, development, and resource use efficiency. Three contrasting short season grain legumes common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.] and lablab [Lablab purpureus (L.) Sweet] were selected to assess their agricultural potential with respect to climate variability and change along the Machakos-Makueni transect in semi-arid Eastern Kenya. This was undertaken using measured data [a water response trial conducted during 2012/13 and 2013/14 in Machakos, Kenya] and simulated data using the Agricultural Production System sIMulator (APSIM). The APSIM crop model was calibrated and validated to simulate growth and development of short-season grain legumes in semi-arid environments. Water use efficiency (WUE) was used as indicator to quantify the production potential. The major traits of adaptation include early flowering and pod and seed set before the onset of terminal drought. Early phenology together with adapted canopy architecture allowed more optimal water use and greater partitioning of dry matter into seed (higher harvest index). While common bean followed a comparatively conservative strategy of minimizing water loss through crop transpiration, the very short development time and compact growth habit limited grain yield to rarely exceed 1,000 kg ha−1. An advantage of this strategy was relatively stable yields independent of in-crop rainfall or season length across the Machakos-Makueni transect. The growth habit of cowpea in contrast minimized water loss through soil evaporation with rapid ground cover and dry matter production, reaching very high grain yields at high potential sites (3,000 kg ha−1) but being highly susceptible to in-season drought. Lablab seemed to be best adapted to dry environments. Its canopy architecture appeared to be best in compromising between the investment in biomass as a prerequisite to accumulate grain yield by minimizing water loss through soil evaporation and crop transpiration. This lead to grain yields of up to 2,000 kg ha−1 at high potential sites and >1,000 kg ha−1 at low potential sites. The variance of observed and simulated WUE was high and no clear dependency on total rainfall alone was observed for all three short-season grain legumes, highlighting that pattern of water use is also important in determining final WUEbiomass and WUEgrain. Mean WUEgrain was lowest for cowpea (1.5–3.5 kggrain ha−1 mm−1) and highest for lablab (5–7 kggrain ha−1 mm−1) reflecting the high susceptibility to drought of cowpea and the good adaptation to dry environments of lablab. Results highlight that, based on specific morphological, phonological, and physiological characteristics, the three short-season grain legumes follow different strategies to cope with climate variability. The climate-smart site-specific utilization of the three legumes offers promising options to design more resilient and productive farming systems in semi-arid Eastern Kenya

Treponema spp. spirochetes and keratinopathogenic fungi isolated from keratomas in donkeys

Keratoma is an aberrant keratin mass thought to originate from epidermal horn-producing cells interposed between the stratum medium of the hoof wall and the underlying third phalanx. The cause is unknown, although the presence of keratomas is frequently associated with chronic irritation, focal infection, or trauma. A total of 167 donkeys with keratomas were presented in this study. The diagnosis of a keratoma was based on clinical signs, radiography, and histopathologic examination. Surgical excision was attempted on all donkeys with lameness unless euthanasia was advised. Histopathologic examination, including Giemsa, periodic acid Schiff, and Young's silver special histochemical stains, was performed and showed the presence of fungal hyphae and spirochete bacteria within the degenerate keratin. Polymerase chain reaction (PCR) for treponeme bacteria was performed on 10 keratoma lesions and 9 healthy pieces of hoof (controls). All healthy donkey tissues were negative for the 3 recognized digital dermatitis (DD) treponeme phylogroups, whereas 3 of 10 (30%) donkey keratoma samples were positive for one of the DD treponeme phylogroups. Routine fungal culture and PCR for fungi were performed on 8 keratoma lesions and 8 healthy pieces of hoof (controls). Keratinopathogenic fungi were detected in 1 of 8 (12.5%) keratomas, while only non-keratinopathogenic, environmental fungi were detected in 8 control healthy hoof samples. This is the first time the DD treponemes phylogroup and keratinopathogenic fungi have been detected in keratomas. Further studies are required to assess the significance of this finding

Multidimensional assessment of smallholder farming systems’ sustainability

A holistic systems-oriented approach is strongly recommended to address the intractable challenges of complex smallholder farm and food systems in different ecologies, and cultures. In the present study, we have developed and piloted a multidimensional framework for assessing farming systems sustainability and resilience (FSSR) which is easily measurable and comparable. It considers five major sustainability domains: environmental, economic, productivity, social and human well-being. Further each domain is divided into different themes, sub-themes and indicators. The indicators have been finalized with rounds of stakeholders’ consultations involving farmers, researchers, development actors besides literature. We identified 115 measurable indicators: environmental (34), economic (29), productivity (12), social (25) and human well-being (15) in the final framework which are aggregated into an index with a maximum value of 100 representing the level of sustainability and resilience at different scales. In our case study the overall sustainability index scores ranged between 42 to 47 across farm types. The overall and domain level sustainability scores varied widely across individual households and farm types. The present framework could be very useful tool for researchers, development actors and institutions to identify entry points to design context-specific strategies to improve sustainability and resilience of farming systems in vulnerable regions

Cross-kingdom signalling regulates spore germination in the moss <i>Physcomitrella patens</i>

Plants live in close association with microorganisms that can have beneficial or detrimental effects. The activity of bacteria in association with flowering plants has been extensively analysed. Bacteria use quorum-sensing as a way of monitoring their population density and interacting with their environment. A key group of quorum sensing molecules in Gram-negative bacteria are the N-acylhomoserine lactones (AHLs), which are known to affect the growth and development of both flowering plants, including crops, and marine algae. Thus, AHLs have potentially important roles in agriculture and aquaculture. Nothing is known about the effects of AHLs on the earliest-diverging land plants, thus the evolution of AHL-mediated bacterial-plant/algal interactions is unknown. In this paper, we show that AHLs can affect spore germination in a representative of the earliest plants on land, the Bryophyte moss Physcomitrella patens. Furthermore, we demonstrate that sporophytes of some wild isolates of Physcomitrella patens are associated with AHL-producing bacteria

Understanding growth and development of three short-season grain legumes for improved adaptation in semi-arid Eastern Kenya

Short-season grain legumes play an important role in smallholder farming systems as source of food and to improve soil fertility through nitrogen fixation. However, it is not clearly understood how these diverse legumes contribute to the resilience of such systems in semi-arid environments. We describe the growth, development and resource-use efficiency (focusing on radiation, RUE) of three promising short-season grain legumes: common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.) and lablab (Lablab purpureus (L.) Sweet). Two field experiments were conducted during the short rains of 2012–13 and 2013–14 in Eastern Kenya. In the first experiment, the legumes were grown at three plant densities (low, medium, high); in the second experiment, they were subjected to three water regimes (rainfed, partly irrigated, fully irrigated). Phenological development was monitored and biomass accumulation, leaf area index and fractional radiation interception were measured repeatedly during growth; grain yield was measured at maturity. Harvest index and RUE were calculated from these data. Common bean had the shortest growing period (70 days), the most compact growth habit and relatively high RUE but limited grain yield (1000–1900 kg ha–1), thereby proving more suitable for cultivation in areas with restricted cropping windows or in intercropping systems. Cowpea had a longer growing period (90 days) and a spreading growth habit leading to high light interception and outstanding grain yields under optimal conditions (1400–3050 kg ha–1). Lablab showed stable RUE values (0.76–0.92 g MJ–1), was relatively unaffected by limited water availability and had a comparatively long growing period (100 days). Lablab grain yields of ~1200–2350 kg ha–1 were obtained across all water regimes, indicating a high potential to cushion climatic variability. Planting density strongly influenced the production success of cowpea and lablab, with high plant densities leading to vigorous growth habit with low podset establishment. Such information on temporal and spatial differences in growth, development and resource-use efficiency is highly valuable for crop-modelling applications and for designing more resilient farming systems with short-season grain legumes

Considering effects of temperature and photoperiod on growth and development of lablab purpureus (l.) Sweet in the search of short-season accessions for smallholder farming systems

Legumes have gained increased importance in smallholder farming systems of sub-Saharan Africa due to their contribution to household nutrition and health and their ability to grow in low fertility soils. With unpredictable and highly variable rainfall characteristics of the semi-arid areas, short-season grain types are seen as a promising option for drought avoidance. Knowledge of phenological development and, in particular, time to flowering is crucial information needed for estimating the possible production success of new accessions to new environments. The photoperiod-sensitivity of 10 promising short-season Lablab purpureus (L.) Sweet accessions (CPI 525313, CPI 52533, CPI 52535, CPI 52535, CPI 52552, CPI 52554, CPI 60795, CPI 81364, CQ 3620, Q 6880B) were evaluated for their response to varying temperature and daylength regimes in field trials in Limpopo province, South Africa and under controlled conditions in growth chamber experiments in Göttingen, Germany. Photoperiod sensitivity was quantified using the triple-plane rate model of flowering response with time to flowering expressed in thermal time (Tt, °Cd). Additionally, piecewise regression analysis was conducted to estimate the critical photoperiod (Pc) above which time to flowering was delayed significantly. Relatively high variation of time to flowering amongst and within accessions in days after planting (DAP) was observed, ranging from 60 to 120 DAP depending on sowing date or daylength/temperature regime. Furthermore, a clear positive effect of temperature on growth and development of the tested accessions was found and time to flowering expressed as thermal time were consistent for the tested accessions, ranging from 600 to 800 °Cd for daylength 110 DAP. The tested lablab accessions are therefore considered photoperiod insensitive, or weakly photoperiod responsive and are classified as short-day plants (SDP). Since daylength does not exceed 13 h between the latitudes 30 N to 30 S, these lablab accessions are recommended for further testing as short-duration grain legumes

Multidimensional framework for measuring sustainability and resilience of farming systems

Natural resources, are fundamental for the structure and function of agricultural systems and for social and environmental sustainability in support of life on earth. Historically, global agricultural development has been narrowly focused on increased productivity rather than on a more holistic integration of natural resource management with food and nutritional security. Now it is strongly suggested that a holistic, or systems-oriented approach, will be needed to address the intractable challenges associated with the complexity of food and other production systems in different ecologies, locations and cultures. In the present study we have developed and piloted a multidimensional framework for assessing farming systems sustainability and resilience (FSSR). The quantification framework is easily measurable and comparable across farm households, farming systems and beyond. It considers five major domains of the farming systems namely environmental, economic, productivity, social and human well-being. In the subsequent stages of measurement each domain is divided into different themes, then sub-themes and indicators. The indicators in our study have been finalized with rounds of stakeholders’ consultations involving farmers, researches, development experts besides literature. Finally, we identified a total of 115 indicators: environmental (34), economic (29), productivity (12), social (25) and human well-being (15) in the final framework which are measurable and would be able to provide an index value representing level of sustainability of farming systems at different scales: farm household, domain and farming system considering appropriate weights of different domains. The FSSR framework could be a very useful tool for designing the context specific strategies to address farm sustainability challenges

Combined application of nitrogen and phosphorus to enhance nitrogen use efficiency and close the wheat yield gap on varying soils in semi‐arid conditions

A primary driver of the wheat yield gap in Australia and globally is the supply of nitrogen (N) and options to increase N use efficiency (NUE) are fundamental to closure of the yield gap. Co‐application of N with phosphorus (P) is suggested as an avenue to increase fertiliser NUE, and inputs of N and P fertiliser are key variable costs in low rainfall cereal crops. Within field variability in the response to nutrients due to soil and season offers a further opportunity to refine inputs for increased efficiency. The response of wheat to N fertiliser input (0, 10, 20, 40 and 80 kg N ha‐1) under four levels of P fertiliser (0, 5, 10 and 20 kg P ha−1) was measured on three key low rainfall cropping soils (dune, mid‐slope and swale) across a dune‐swale system in a low rainfall semi‐arid environment in South Australia, for three successive cropping seasons. Wheat on sandy soils produced significant and linear yield and protein responses across all three seasons, while wheat on a clay loam only produced a yield response in a high rainfall season. Responses to P fertiliser were measured on the sandy soils but more variable in nature and a consistent effect of increased P nutrition leading to increased NUE was not measured

Improving the productivity of millet based cropping systems in the West African Sahel: Experiences from a long-term experiment in Niger

Resource-poor farmers who are living in the harsh environments of the West African Sahel (WAS) depend on subsistence orientated, low-input farming systems for meeting their livelihood needs. These largely extractive farming systems have resulted in nutrient depletion, soil fertility decline, low productivity and land degradation. A study conducted over 25 years in Niger, aimed to evaluate the long-term effects of organic and mineral fertilizers, cropping systems (CS) of millet and cowpea on crop productivity. The traditional millet/cowpea intercrop system without P fertilizer (TrM/C) was compared with four improved CS receiving P fertilizer: sole millet (MM), millet/cowpea intercrop (M/C), millet-cowpea rotation (M-C), and M/C and rotation with cowpea (M/CC). Nitrogen fertilizer (N) and the residues of millet (CR) were applied alone or in combination in all five cropping systems. CR were always applied as mulch. The traditional system (TrM/C) produced the lowest millet grain yields (GY) (0.02–0.43 t/ha). All the four improved CS (MM, M/C, M-C and M/C-C) increased GY compared with the traditional system (TrM/C). The M/C and MM systems increased millet GY 3 and 3.3 times compared with the TrM/C, respectively. The M/C-C and M-C systems produced 4 and 4.2 times more GY than that of the TrM/C system, respectively. The lowest revenue was obtained with the TrM/C system. Except for the TrM/C, the revenue of the MM system was lower compared with combined cultivation of millet and cowpea. Compared with the TrM/C system, M/C and M/C-C provided 2 times more revenue. By providing 2.4 times more revenue than the TrM/C system, the M-C system was the most productive system. Cowpea provided from 54% and 56% of the revenue in M/C-C and M-C system, respectively. Soil organic carbon decreased in all the CS from 46% to 63% compared with the soil kept under natural vegetation fallow. The improved CS increased soil P from 3.4 to 4 times. Over the 25 years of cropping, the highest millet yields were obtained with the lower levels of rainfall indicating the role of nutrients in the system. The four improved systems maintained millet yields over the 25 years of cropping. By improving water and nutrient use efficiency, integrated management of mineral fertilizers, CR and cowpea affected more crop productivity than the rainfall. We concluded that cereal-legume based cropping systems treated with small doses of mineral fertilizers and CR could be used for sustainable management of soil fertility in low-input farming systems

Health service changes to address diabetes in pregnancy in a complex setting: perspectives of health professionals

Background: Australian Aboriginal and Torres Strait Islander women have high rates of gestational and pre-existing type 2 diabetes in pregnancy. The Northern Territory (NT) Diabetes in Pregnancy Partnership was established to enhance systems and services to improve health outcomes. It has three arms: a clinical register, developing models of care and a longitudinal birth cohort. This study used a process evaluation to report on health professional's perceptions of models of care and related quality improvement activities since the implementation of the Partnership. Methods: Changes to models of care were documented according to goals and aims of the Partnership and reviewed annually by the Partnership Steering group. A 'systems assessment tool' was used to guide six focus groups (49 healthcare professionals). Transcripts were coded and analysed according to pre-identified themes of orientation and guidelines, education, communication, logistics and access, and information technology. Results: Key improvements since implementation of the Partnership include: health professional relationships, communication and education; and integration of quality improvement activities. Focus groups with 49 health professionals provided in depth information about how these activities have impacted their practice and models of care for diabetes in pregnancy. Co-ordination of care was reported to have improved, however it was also identified as an opportunity for further development. Recommendations included a central care coordinator, better integration of information technology systems and ongoing comprehensive quality improvement processes. Conclusions: The Partnership has facilitated quality improvement through supporting the development of improved systems that enhance models of care. Persisting challenges exist for delivering care to a high risk population however improvements in formal processes and structures, as demonstrated in this work thus far, play an important role in work towards improving health outcomes.R. Kirkham, J.A. Boyle, C. Whitbread, M. Dowden, C. Connors, S. Corpus, L. McCarthy, J. Oats, H.D. McIntyre, E. Moore, K. O’Dea, A. Brown, L. Maple-Brown (On behalf of the NT Diabetes in Pregnancy Partnership