Mixed Farming Systems Research Articles

ASSESSING LIVESTOCK WATER PRODUCTIVITY IN MIXED FARMING SYSTEMS OF GUMARA WATERSHED, ETHIOPIA

SUMMARYA monitoring study was carried out in Gumara watershed, upper Blue Nile basin, with the objective of evaluating livestock water productivity (LWP) using a life cycle assessment method. Sixty two smallholder farmers were selected for the study implemented between November 2006 and February 2008. Data on crop and livestock production were collected to allow assessment of livestock water productivity. Study sites were situated in three different rainfed mixed crop/livestock farming systems; barley/potato based system (BPS), tef/finger-millet based system (TMS), and rice/noug based system (RNS). LWP was found to be significantly lower (p < 0.01) in RNS (0.057 USD m−3 water) than in TMS (0.066 USD m−3 water) or in BPS (0.066 USD m−3 water). Notably, water requirement per kg live weight of cattle increased towards the lower altitude area (in RNS) mainly because of increased evapo-transpiration. As a result, 20% more water was required per kg live weight of cattle in the low ground RNS compared to BPS situated in the upstream parts of the study area. Cattle herd management that involved early offtake increased LWP by 28% over the practice of late offtake. Crop water productivity expressed in monetary units (0.39 USD m−3 water) was higher than LWP (0.063 USD m−3 water) across the mixed farming systems of Gumara watershed. Strategies for improving LWP, from its present low level, could include keeping only the more productive animals, increasing pasture productivity and linking production to marketing. These strategies would also ease the imbalance between the existing high livestock population and the declining carrying capacity of natural pasture.

Genetics and Genomics of Cotton Leaf Curl Disease, Its Viral Causal Agents and Whitefly Vector: A Way Forward to Sustain Cotton Fiber Security.

Cotton leaf curl disease (CLCuD) after its first epidemic in 1912 in Nigeria, has spread to different cotton growing countries including United States, Pakistan, India, and China. The disease is of viral origin—transmitted by the whitefly Bemisia tabaci, which is difficult to control because of the prevalence of multiple virulent viral strains or related species. The problem is further complicated as the CLCuD causing virus complex has a higher recombination rate. The availability of alternate host crops like tomato, okra, etc., and practicing mixed type farming system have further exaggerated the situation by adding synergy to the evolution of new viral strains and vectors. Efforts to control this disease using host plant resistance remained successful using two gene based-resistance that was broken by the evolution of new resistance breaking strain called Burewala virus. Development of transgenic cotton using both pathogen and non-pathogenic derived approaches are in progress. In future, screening for new forms of host resistance, use of DNA markers for the rapid incorporation of resistance into adapted cultivars overlaid with transgenics and using genome editing by CRISPR/Cas system would be instrumental in adding multiple layers of defense to control the disease—thus cotton fiber production will be sustained.

Effects of climate change and adaptation on the livestock component of mixed farming systems: A modelling study from semi-arid Zimbabwe

Large uncertainties about the impacts of climate change and adaptation options on the livestock component of heterogeneous African farming systems hamper tailored decision making towards climate-smart agriculture. This study addressed this knowledge gap through the development and use of a dynamic modelling framework integrating climate, crop, pasture and livestock models. The framework was applied to a population of 91 farms located in semi-arid Zimbabwe to assess effects on livestock production resulting from climate change and management interventions. Climate scenarios representing relative “cool-wet”, “hot-dry” and “middle” conditions by mid-century (2040–2070) for two representative concentration pathways were compared with the baseline climate. On-farm fodder resources and rangeland grass production were simulated with the crop model APSIM and the pasture model GRASP respectively. The simulated fodder availability was used in the livestock model LIVSIM to generate various production indicators including milk, offtake, mortality, manure, and net revenue. We investigated the effects of two adaptation packages targeting soil fertility management and crop diversification and quantified the sensitivity to climate change of both current and improved systems. Livestock productivity was constrained by dry-season feed gaps, which were particularly severe for crude protein and caused by the reliance on rangeland grazing and crop residues, both of low quality in the dry season. Effects on grass and stover production depended on the climate scenario and the crop, but year-to-year variation generally increased. Relative changes in livestock net revenue compared to the baseline climate varied from a 6% increase to a 43% decrease, and the proportion of farmers negatively affected varied from 20% to 100%, depending on the climate scenario. Adverse effects of climate change on average livestock production usually coincided with increased year-to-year variability and risk. Farms with larger stocking density faced more severe feed gaps and were more sensitive to climate change than less densely stocked farms. The first adaptation package resulted in increased stover production and a small increase in livestock productivity. The inclusion of grain and forage legumes with the second package increased milk productivity and net revenues more profoundly by 30%. This was attributed to the alleviation of dry-season feed gaps, which also reduced the sensitivity to climate change compared to the current system. Clearly, individual farms were affected differently by climate change and by improved farm management, illustrating that disaggregated impact assessments are needed to effectively inform decision making towards climate change adaptation.

Identifikasi Sistem Budidaya, Pemanfaatan dan Analisis Nutrisi Sayur Hitam (Rungia Klossii) Asal Distrik Mapia Kabupaten Dogiyai

The objective of this research is to identify the farming systems and the utilization of sayur hitam (Rungia klossii) by the Mee tribe in the Regency of Dogiyai as well as to provide information about the nutrients in the R. klossii. Descriptive method with direct observation is used in the field to examine the farming system and crop nutrient content. Analytical procedures were implemented using Gravimetry and atomic absorption spectrophotometry. The analysis were conducted in the Laboratory of Chemistry, Faculty of Science, University of Papua on April 2016. The variables observed by those methods include the identification of farming systems and the crop nutrient content in the leaves. Farming systems applied by the community to cultivate Rungia klosii is a mixed farming systems based on local knowledge. Based on the analysis of the nutrient content of Rungia klossii in terms of water content, oil content of fat, iron levels, manganese content, the levels of calcium and magnesium levels, the magnesium levels in Rungia klosii is 272.0892 mg/L which is the highest.

Diversity and importance of local fodder tree and shrub resources in mixed farming systems of central Kenya

Locally available tree fodder resources are seldom considered in livestock feeding strategies despite their nutritional potential to supplement grass forages. Knowledge gaps on species availability and utilization may be the cause. This study surveyed 117 random farms locatedin humid (Githunguri and Lari) and drier parts (Kayatta) of central Kenya to identify fodder trees and shrubs diversity available to supplement existing livestock feeding options. Major forage and feed types used by farmers include napier grass (98.2%); maize and bean stover (85.7%); banana stover (60.5%), dairy meal (60.1%), hay (58.3%) and fodder trees (57.7%). A total of 60 fodder tree and shrub species were found on farm. Indigenous species comprised 65% of total richness but only 12% of the total abundance. The most common exotic and indigenous trees were Grevillea robusta and Persea americana, and Acacia tortilis and Terminalia brownii, respectively. Mean species richness per farm was 6.8 with significantly higher richness in Kayatta (10) compared to Lari and Githunguri (both 5.4, p < 0.05). Land size had a positive influence on total indigenous species richness and abundance on farms while the number of dairy cows had a negative influence. Findings confirm availability of diverse tree fodder trees to supplement current feeding options. However, where farms are small, farmers may require external feed sources as limited tree richness and abundance may not support profitable dairy farming.

Farmers’ perceptions of climate change and its implication on livestock production in mixed-farming system areas of Bale highlands, Southeast Ethiopia

Farmers’ perceptions of climate change and its implication on livestock production in mixed-farming system areas of Bale highlands, Southeast Ethiopia

Genotype by environment interactions for grain yield of perennial rice derivatives (Oryza sativa L./Oryza longistaminata) in southern China and Laos

Perennial grains have been proposed to stabilise fragile lands while contributing grain and grazing in mixed farming systems. Genotype by environment (GxE) interactions for grain yield were investigated in 22 perennial rice (Oryza sativa L./Oryza longistaminata) derivatives over four successive growing seasons at three sites in Yunnan in southern China and one site in Lao PDR. The GxE interaction accounted for 25.7% of the total sum of squares, with environment and genotype responsible for 57.4% and 16.9%, respectively. Cluster analysis identified seven environment and six genotype groups, which accounted for 55.6% of the GxE sum of squares. Principal component axes 1, 2 and 3 accounted for 42.3%, 19.1% and 16.5% of the GxE-SS, respectively, with PCA1 indicating yield potential, PCA2 delay in phenology under environmental stress, and PCA3 ratoon percentage. Environment groups differed in mean temperature, whether dry season or wet season, and occurrence of environmental stresses, such as periods of low minimum temperature or periods of rainfall deficit. Genotype groups differed in adaptation to these diverse environments. For genotype groups, G5 (PR23) was highest-yielding and broadly adapted across environments, while G1 (line 188, both 137s, both 139s, both 147s) was low-yielding and poorly adapted. Other genotype groups showed preferential adaptation: G3 (lines 60, 251, 264, Bt69, Bt71) to Simao/Dry Season (E3 and E4), G4 (lines 75, 243, 246, 249, 255) to Menglian/Wet Season (E1 and E2), G2 (line TZ) to Jing Hong 2013 (E7), and G6 (lines 56, 59, 214) to Jing Hong 2102 and Na Pok (E6 and E5). The results imply that regrowth success and maintenance of spikelet fertility over regrowth cycles are important for adaptation of perennial rice, especially to low minimum temperature at higher altitude and rainfall deficit at lower altitude, and future breeding programmes in perennial rice should address these environmental stresses. The high yield and broad adaptation of PR23 (G5) over environments makes it a prime candidate for release to stabilise fragile lands in the humid and subhumid tropics, while contributing grain and forage in mixed-farming systems.

Conception participative d’innovations et accompagnement des projets d’élevage familiaux au Burkina Faso : explorer, expérimenter et évaluer

Une grande majorité des polyculteurs éleveurs de l’ouest du Burkina Faso ont un projet d’élevage familial (PEF) en tête. Cependant, plus de la moitié des pro­jets ne démarrent même pas. Parmi ceux mis en place, d’importantes faiblesses sont observées au niveau de la gestion de l’alimentation du bétail, ce qui com­promet leur rentabilité économique. Cet article présente une démarche de conception et d’accompagnement de projet d’élevage familial (Capef) conduit en partenariat entre le producteur et un conseiller. Elle permet d’accompagner le producteur dans la préparation, l’exécution et l’évaluation de son projet. La démarche a été élaborée avec 10 producteurs qui avaient des PEF bovins de trait, bovins à l’engraissement ou vaches laitières en préparation. La Capef se déroule en quatre étapes : a) le diagnostic, b) le calibrage et la recherche d’options d’amélioration, c) la mise en œuvre et l’ajustement, et d) l’évaluation. Dans cette approche de conception d’accompagnement, les producteurs ont mis au point le PEF progressivement, en même temps qu’ils ont appris à le pilo­ter, en réorganisant leur travail et l’allocation de leurs moyens de production. La Capef a aidé les producteurs à développer les apprentissages permettant la maîtrise des pratiques d’alimentation et des stratégies d’élaboration d’un projet d’élevage pour mieux le réussir. Pour le chercheur, elle a permis de comprendre la rationalité des éleveurs en participant avec eux à la construction et à la mise en œuvre de leur PEF.

Analysis of crop residue use in small holder mixed farms in Ethiopia

AbstractDeterminants of the use of cereal and pulse residue for livestock feeding and soil mulching among smallholder farmers in the mixed farming system were analyzed. Crop residue (CR) is dual purpose resources in the mixed crop–livestock systems of the Ethiopian highlands. They serve as livestock feed and inputs for soil and water conservation. They are generated predominantly from cereals and pulses. However, in view of the allocation of CR, soil conservation and livestock are two competing enterprises. Identifying the determinants of the intensity of use of cereal and pulse residue may help in designing strategies for more efficient CR utilization. Data on CR were generated and its utilization was collected in two highland regions in Ethiopia from 160 households using a structured questionnaire. The data were analyzed using the multivariate Tobit model. Results of the study showed that farmers prefer using CR from pulses over CR from cereals for livestock feeding purposes. The proportion of CR from pulses that was used as feed was positively affected by education level of the farmer, livestock extension service, number of small ruminants and CR production from the previous season. Distance of farm plots from residences of the farm households negatively affected the proportions of cereal and pulse residue used for feed. The use of pulse residue increased significantly when the women participated in decision making on CR utilization. The proportion of cereal and pulse residue used for soil mulch was positively affected by the education level of the farmer, the distance between the homestead and the cultivated land, extension service, awareness about soil mulch, the slope of cultivated land, participation in farmer-to-farmer extension and CR generated in the preceding season. In view that pulse CR have better nutritive value compared with cereal CR, better utilization of CR could be achieved by maximizing the use of pulse residue as livestock feed and optimizing the use of cereal residue as soil mulch. More livestock extension on the nutritive value of pulse residue should be provided to the farmers who cultivate sloppy plots. Encouraging the culture of labor exchange among the farmers could result in increased labor availability in the farms that would facilitate the transport and storage of pulse residue and increase its use as livestock feed. Increasing the awareness among farmers about the superiority of the pulse residue over cereal residue as feed and encouraging use of cereal residue as soil mulch could optimize the utilization of CR in the household.

Development of Animal Husbandry and Dairying in Second Five Year Plan (1956 to 1961)

&lt;p&gt;&lt;em&gt;After independence in 1947, the Government of India started organized plan for the development of the country. Visible impact was not felt during the 1&lt;sup&gt;st&lt;/sup&gt; plan period. Regular famine, division of country created a situation where supply of food to country men was a major problem before the Government. According during the second five year plan emphases was given on the development of agriculture and animal husbandry sectors. The second five year plan started in 1956. An outlay of Rs 56 crores was provided by the Government of India for development of animal husbandry and dairying. The object of animal husbandry programme was to supply milk, meat and eggs in order to balance the customary Indian diets and to provide bullock power for agricultural operations.&lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt;&lt;p&gt;&lt;em&gt;In addition to by Products of agricultural food crops, residuesgrazing areas had been the main stay for cattle. Increase in the requirements of agriculture land for food production for the human population, development of industries road &amp;amp; buildings grazing areas have steadily diminished. Cattle raising had to undergo a basic change in the sense that its future would depend on mixed farming system. Most of the fodder have to be grown on the holding of the farmers.&lt;/em&gt;&lt;/p&gt;

Soil acidity under multiple land-uses: assessment of perceived causes and indicators, and nutrient dynamics in small-holders’ mixed-farming system of northwest Ethiopia

ABSTRACTKnowledge on farmers’ perspectives is of paramount importance in order to design appropriate agricultural research and development interventions attuned to local farming systems. A participatory rural appraisal was conducted in order to understand perceived causes and indicators of soil acidity under multiple land-uses in three Districts of northwest Ethiopia. Soil samples were also collected from five dominant land-uses. The samples were analysed for soil pH, exchangeable acidity and other physico-chemical properties. The result indicated that the pH(H2O) of most of the soils in the study sites were in a strongly acidic range (4.6–5.5). Gashena Akayita of the Banja District was the most acidic of all. Among the land-uses, eucalyptus fields were the most acidic followed by crop outfields and grazing lands in that order. At all the study sites, exchangeable Al was detected in soils having a pH of less than 5.0. Overall, the nutrient dynamics showed variation across land-uses and study sites. Farmers’ perceived causes of soil acidity included: soil erosion; contending use of fertility replenishing local resources; abandoning traditional fertility management practices and minimal use of external inputs. The farmers attributed the exclusive use of acid-forming inorganic fertilizers to exhaustion of the soil. Various land and soil characteristics, plant growth attributes, changes in genetic diversity were mentioned as indicators of soil acidity. Particularly, the farmers used prevalence of acidophilic weed species on crop fields and grazing lands as marker of strongly acidic soil. Farmers’ perceived causes and indicators were in agreement with scientific facts and can be utilized as input in designing sustainable acid soil management strategies. Decline in genetic diversity of the once widespread crop species and land races, and expansion of newly introduced soil acidity tolerant species, suggests the need to undertake rescue collections in these areas.

Grazing winter and spring wheat crops improves the profitability of prime lamb production in mixed farming systems of Western Australia

Grazing immature cereal crops, particularly different varieties of wheat, has become widely adopted in the high rainfall areas of southern Australia. Recently, there has been growing interest in applying this technology in drier parts of the mixed farming zones of Western Australia. A modelling study was conducted to examine farm business returns with or without the grazing of immature wheat (winter and spring varieties) in different locations of Western Australia (Merredin, Wickepin and Kojonup), representing the low to high rainfall (319–528 mm) cropping regions, respectively. A combination of APSIM (crop simulation model) and GrassGro (pasture and livestock simulation model), were used to evaluate the changes in farm gross margins with the grazing of cereal crops at three locations of Western Australia. The results of the study showed that grazing the two wheat varieties (dual-purpose winter and spring) at the high rainfall location increased the profitability of the livestock enterprise by 2.5 times more than grazing crops at both low rainfall locations (P &lt; 0.05). Across all years and sites, the average supplementary feeding costs were reduced by the inclusion of grazed winter (12%) and spring (2%) wheat crops in the lamb production system. The comparative reduction in the cost of supplementary feeding varied between locations and by crop variety within locations, due to both the frequency and average duration of the grazing of wheat crops in these regions, and the farm-stocking rate that was chosen. Both wheat varieties were grazed frequently at the lowest rainfall site (68% and 30% of years for winter and spring wheat varieties respectively), whereas grazing spring wheat was less frequent at the higher rainfall location and averaged 16% of years due to a greater difference in the relative availability of wheat crops versus pasture for grazing among regions. The grazing model assumed that there were abundant productive mixed ryegrass and subterranean clover pasture in the farming system. Overall, this study suggests that both winter and spring wheat crops are likely to supply green feed during the winter feed shortage (April–July) and reduce supplementary feed requirements for a short period of time in some seasons. The value of grazing crops is likely to be higher on farms with poorer soils and less productive pastures.

The Analysis of Potato Farming Systems in Chencha, Ethiopia: Input, Output and Constraints

A household survey was conducted for mixed farming systems in Chencha, Ethiopia. Goals of the survey were to establish a baseline for the current production system, to quantify the variation in input and output, and to identify constraints hindering expansion of potato production. Descriptive statistics and principal component analysis were computed using SPSS and XLSTAT. Input and product use constraints varied over household characteristics. Using improved varieties, inorganic fertilizers, and selling products strongly and positively correlated with the households’ wealth, adoption, and education levels. Problems of cash and inadequate produce negatively correlated with wealth, adoption factors, and education levels. Access to improved varieties, training, and fertilizer were positively correlated with age, family size and gender. Land and labour shortages and pests were identified as cross-cutting constraints. Results of the analysis identify a need for a pluriform advisory model recognizing and building upon alleviation of the diversity of constraints identified in this analysis.

Effects of changing farm management and farm structure on energy balance and energy-use efficiency—A case study of organic and conventional farming systems in southern Germany

Abstract Fossil energy input, energy output, and energy use- efficiency (EUE) are important indicators of the environmental effects, resource consumption and economic performance of farming systems. In this study, the energy balance (process analysis) and EUE of different organic and conventional farming systems – mixed farming, arable farming, and agroforestry (AGFS) systems – were analyzed due to their importance in Germany. The analysis was based on long-term experiments at the Scheyern Research Farm in southern Germany. The results showed that the conversion from multi-structured organic mixed farming to a specialized organic arable farming system reduced the fossil energy input in crop production only marginally (from 5.9 to 5.5 GJ ha −1 yr −1 ), but considerably decreased dry matter yield (from 5.4 to 2.5 Mg ha −1 yr −1 ), energy output (from 99 to 46 GJ ha −1 yr −1 ) and EUE (from 16.8 to 8.3). Improved management in the conventional arable farming system (with high-yielding varieties and better N management) reduced the energy input from 14.0 to 12.2 GJ ha −1 yr −1 , increased the energy output from 155 to 179 GJ ha −1 yr −1 , and elevated the EUE from 11.1 to 14.6. The establishment of AGFS with short rotation trees (without fertilization and pesticide use) led to the reduction of energy input. Based on the results, we concluded that mixed farming is one of the best ways of producing food with high EUE under the conditions of organic farming. Therefore the conversion from organic mixed farming to an organic arable farming system is not recommended. Our AGFS results were from the first stage of a long-term experiment; it showed no negative effects on DM yield and energy output and positive effects on energy-use efficiency at this stage. However, further research is needed to know the long-term influence of AGFS.

Impact of climate changes on existing crop-livestock farming systems

The state of Western Australia is a major producer and exporter of crops and livestock. Mixed farming systems are typical agricultural enterprises in the Western Australian wheatbelt where climate drives the productivity and profitability of these farms and therefore the effects of likely climate change on their performance need to be understood. Here the effects of climate change projected at 2030 were evaluated compared to a baseline period (1980–1999) on mixed farming systems at paddock, enterprise and whole farm scales using the coupled APSIM and GRAZPLAN biophysical simulation models. The yield of different crops, livestock production and gross margins were assessed under current and projected climates using current farming technology and management practices. Representative mixed-farm systems were selected along a climate transect. Modelling analysis suggests that current production levels and gross margins of mixed farm systems in Western Australia will not be sustained in 2030 climate conditions except in areas of moderately high-rainfall. Whole farm gross margin declined at all site×potential climate scenarios between 1% and 22% except in moderately high rainfall where gross margin increased by up to 4% under a ‘hot and moderate change in rainfall’ climate. Projected crop yields declined for most of the crop×site×potential climate combinations, with greatest declines under a hot and dry climate (at driest margin of transect) in which wheat, barley, canola, and lupin yield declined up to 16%, 15%, 21%, and 27%, respectively. Increase in yield was predicted for wheat and barley at some of the site×potential climate s. Wheat yield increased only under moderately high rainfall region by 6% while barley increased by 1%. Simulated cropping gross margin was also shown to decline by between >1% and 23%, except for the moderately high-rainfall site where cropping gross margins were projected to increase by up to 3%. Changes in simulated livestock production were smaller and less variable than for crop production. The change in weight of livestock sold across sites×potential climate combinations ranged between −3% and +3%. Livestock gross margin varied between −11% and +6%. Modelling results indicated a greater fertilisation effect of the elevated CO2 on pasture production than on crop yield and biomass particularly in drier sites. But however, this could not offset negative impact of climate change under hot potential climates. The main negative environmental impacts from the projected climate change were declines in annual net primary production (ANPP), ground cover and water use efficiency mostly at drier sites. Whole farm N2O emission declined significantly for the majority of site×potential climate combinations, while smaller decreases in ruminant CH4 emission were predicted. In 2030, returns from livestock enterprises are predicted to be smaller, but less variable than from cropping and with increasing probability of success in drier regions. Reduced variability in financial return is important from the perspective of whole farm risk management. Shifts in enterprise mix in dryland mixed-farming systems towards increased livestock may be a helpful strategy in adapting to climate change and managing the associated financial risks.

Livestock feed resources utilization practices in Tanqua-Abergelle district of Tigray, Northern Ethiopia.

A study was carried out with the objective to assess the utilization practices of local feed resources. It was implemented in Tanqua-Abergelle district of the Tigray region, Northern Ethiopia. Lemlem and Gera peasant associations (PAs) were selected purposively based on their potentiality in livestock resources and road access for household (HH) interview purpose. Likewise, Sheka-Tekli and Hadinet PAs were chosen for the purpose of focus group discussion (FGD). A total of 60 HHs (30 from each PA) were selected randomly for interview using semi-structured questionnaire. About 16% of the respondents were female HHs. Two FGDs were held with key informants. The collected data were analyzed using SPSS (2013, version 21) statistical software procedures. The study area is characterized by mixed crop-livestock farming system with high interaction between crop and livestock. Livestock are the mainstay for the farm community with many benefits as sources of draught, meat, milk, income, and manures. Cattle are kept primarily for the purpose of draught power with meat and milk as secondary products, whereas shoats are kept mainly for cash income, manure, meat, and milk. The land holding size per HH was 1.44ha while the herd size was 4.93 tropical livestock unit (TLU). Almost all the land holding (97%) is allocated for crop cultivation with lesser for forage production (<1%) indicating poor attention for fodder harvesting. The cattle herd is composed of local breeds (99%) with less exotic/crossbred (1%), indicating that the livestock rearing is practiced using local breed. Crop residues, natural pastures, stubble grazing, hay, and browsing are the main feed resources for animals. The availability and contribution of each feed vary with season and areas. Sorghum stover is the main feed source in the area and followed by maize stover, Eragrostis tef straw, and pulse straws. Crop residues are fed as basal diet with no or less supplementation using local concentrates like Attela and mill by-products. Industrial by-products are rarely used in the livestock feeding system for their high price and less availability. Likewise, improved forages are not widely utilized as feed sources.

Climate change adaptation and mitigation in smallholder crop–livestock systems in sub-Saharan Africa: a call for integrated impact assessments

African mixed crop–livestock systems are vulnerable to climate change and need to adapt in order to improve productivity and sustain people’s livelihoods. These smallholder systems are characterized by high greenhouse gas emission rates, but could play a role in their mitigation. Although the impact of climate change is projected to be large, many uncertainties persist, in particular with respect to impacts on livestock and grazing components, whole-farm dynamics and heterogeneous farm populations. We summarize the current understanding on impacts and vulnerability and highlight key knowledge gaps for the separate system components and the mixed farming systems as a whole. Numerous adaptation and mitigation options exist for crop–livestock systems. We provide an overview by distinguishing risk management, diversification and sustainable intensification strategies, and by focusing on the contribution to the three pillars of climate-smart agriculture. Despite the potential solutions, smallholders face major constraints at various scales, including small farm sizes, the lack of response to the proposed measures and the multi-functionality of the livestock herd. Major institutional barriers include poor access to markets and relevant knowledge, land tenure insecurity and the common property status of most grazing resources. These limit the adoption potential and hence the potential impact on resilience and mitigation. In order to effectively inform decision-making, we therefore call for integrated, system-oriented impact assessments and a realistic consideration of the adoption constraints in smallholder systems. Building on agricultural system model development, integrated impact assessments and scenario analyses can inform the co-design and implementation of adaptation and mitigation strategies.F

Nitrogen balances and nitrogen-use efficiency of different organic and conventional farming systems

Nitrogen (N) is the most important yield-limiting factor in agricultural systems, however, N application can lead to emissions and environmental problems such as global warming (N2O) and groundwater contamination (NO3 −). This study analyses the N balance, nitrogen-use efficiency, and N loss potential of conventional farming systems (arable farming, improved arable farming, and agroforestry) and organic farming systems (mixed farming, arable farming, and agroforestry) based on long-term field experiments in southern Germany. The effects of the conversion of farm structure and N management are identified. The conventional farming systems in this study were high N-input and high N-output systems. The conventional arable farming system had the lowest nitrogen-use efficiency and the highest N surplus. An optimised N management and the use of high-yielding crop varieties improved its nitrogen-use efficiency. The establishment of conventional agroforestry resulted in the reduction of N input, N output and N surplus, while maintaining high yields. The organic mixed farming system is characterised by a relatively high N input and N output, the accumulation of soil organic nitrogen, the highest nitrogen-use efficiency, and the lowest N surplus of all analysed systems. These good results can be attributed to the intensive farm N cycle between soil–plant–animal. The shift from organic mixed farming to organic arable farming system extensified the N cycle, reduced N input, crop yield and N output. The change from organic arable farming to organic agroforestry reduced the N input, increased the biomass yield, and remained the N surplus within an optimal range.

Comparing the environmental performance of mixed and specialised dairy farms: the role of the system level analysed

Mixed crop–livestock systems are often considered more environmental friendly compared to specialised systems, but due to the interactions between different farming activities, it is not trivial to quantify possible benefits. Using life cycle assessment (LCA), we tested different allocation procedures and system expansion through avoided burden to compare the environmental impact of milk from either specialised or mixed dairy production systems (product level). In a second approach, we compared the whole farming systems with additive system expansion, where the functional unit comprised milk, live animals sold for meat production and crops (farm level). On the product level, milk from the mixed farm had higher non-renewable cumulative energy demand, terrestrial ecotoxicity and phosphorus use, but lower aquatic eutrophication N, independently of the allocation method. For all other impact categories, differences were not significant. On the farm level, results were partially reversed. The mixed system had a lower energy demand and potassium use, while phosphorus use was higher. All other differences were not significant on farm level. The different rankings on product and on farm level were caused by the way manure was attributed to the farming activities. In order to avoid allocation, manure management was sub-divided into storage and application processes. Storage was attributed to dairy production, application to dairy production only if applied on grassland or feed crops, and to cash crops when applied to produce these crops. Manure applied on cash crop areas was thus out of the scope of the product approach, and mineral fertilisers that could be saved within the cash crop production were thus not attributed to milk production. We conclude that only system expansion was able to cope with the complexity of mixed farming systems in LCA. Based on our results with modelled farms, mixed farming showed the potential to reduce environmental impacts compared to specialised farming. Nevertheless, due to the complexity of the system regarding farm management and interactions between cropping and livestock activities, only an assessment with real farm data could reveal the actual benefits of such systems.

Variation in feed utilisation by sheep undergoing compensatory growth following underfeeding with and without additional dietary nitrogen in western China

Small mixed farming systems in developing economies often rely on compensatory growth to recover livestock weight lost during seasonal feed shortages; however, deficit feed management may continue to affect the capacity of livestock to efficiently use feeds even after adequate feeding has resumed. Accordingly, we compared the difference in liveweight gain and feed utilisation over time in Tan weaner sheep in western China, during a period of ad libitum compensatory feeding after alternative feed deficit scenarios. During the feed deficit period, sheep were offered, at 80% maintenance requirements, corn straw, corn grain and lucerne hay in a respective ratio of either 80 : 20 : 0 (S1 ration: metabolisable energy = 7 MJ/kg DM, crude protein = 40 g/kg DM) or 55 : 20 : 25 (S2 ration: metabolisable energy = 8 MJ/kg DM, crude protein = 65 g/kg DM) for 20 days. All sheep were then offered an ad libitum supply of the S2 ration for a further 20 days, during which DM digestibility (DMD), energy intake and liveweight was measured and compared at 5-day intervals. Results indicated that sheep previously fed the S1 ration were not able to digest as much of the ad libitum S2 ration as those previously fed the S2 ration, experiencing significantly lower DMD, energy intake and average daily weight gain. The difference in the effect of the two restrictive feeding treatments on the digestibility of the ad libitum S2 ration gradually decreased over time, indicative of a recovery adaptation during ad libitum feeding period. The rate of DMD recovery post-realimentation was greater in the S1 sheep, likely due to their significantly lower DMD values immediately following underfeeding. We concluded that the comparatively higher nutritive value of the S2 ration sustained rumen digestive function throughout the restrictive feeding period, permitting sheep to commence re-feeding under conditions that are more favourable. Additionally, it is evident that reliance on livestock winter rations typical in western China, as expressed by the S1 ration, degraded ruminant digestive conditions to such an extent that feed was used with reduced efficiency even after being supplied in adequate quantities.