Letteratura scientifica selezionata sul tema "Cash crop intensification"

Integrating perennial groundcovers (PGC) — sometimes referred to as living mulches or perennial cover crops — into annual cash-crop systems could address root causes of bare-soil practices that lead to negative impacts on soil and water quality. Perennial groundcovers bring otherwise absent functional traits — namely perenniality — into cash-crop systems to preserve soil and regenerate water, carbon, and nutrient cycles. However, if not optimized, they can also cause competitive interactions and yield loss. When designing PGC systems, the goal is to maximize complementarity — spatial and temporal separation of growth and resource acquisition — between PGC and cash crops through both breeding and management. Traits of interest include complementary root and shoot systems, reduced shade avoidance response in the cash-crop, and PGC summer dormancy. Successful deployment of PGC systems could increase both productivity and profitability by improving water- and nutrient-use-efficiency, improving weed and pest control, and creating additional value-added opportunities like stover harvest. Many scientific questions about the inherent interactions at the cell, plant, and ecosystem levels in PGC systems are waiting to be explored. Their answers could enable innovation and refinement of PGC system design for multiple geographies, crops, and food systems, creating a practical and scalable pathway towards resiliency, crop diversification, and sustainable intensification in agriculture.

Forage crops have the potential to serve multiple functions, providing an ecological framework to sustainably intensify food production, i.e., ecological intensification. We review three categories of forages (annual forages, perennial forages, and dual-use perennial crops/forages) we believe hold the greatest promise for ecologically intensifying food production. Annual cover crops can provide additional forage resources while mitigating nutrient losses from agricultural fields when they are intercropped with, interseeded into, or following an annual crop, for instance. The integration of perennial forages either temporally, such as annual crop rotations that include a perennial forage phase, or spatially, such as the intercropping of perennial forages with an annual cash crop, provide weed suppression, soil quality, and yield and crop quality benefits. Dual-use crops/forages can provide forage and a grain crop in a single year while providing multiple ecological and economic benefits. However, tradeoffs in balancing multiple functions and limitations in reducing the risks associated with these practices exist. Advancing our understanding of these systems so we can overcome some of the limitations will play a critical role in increasing food production while promoting positive environmental outcomes.

Integrating cover cropping into crop–fallow rotation has been considered a key component of ecological intensification that could mitigate negative productivity and sustainability challenges associated with conventional fallow practices. However, the adoption of cover crops in water-limited environments has been limited by potential soil water and nitrogen (N) costs and resulting yield penalties. We examined the impacts of diverse cover crops on fallow soil water and mineral N dynamics and the legacy impacts on subsequent cash crop productivity and profitability. The cover crops used (forage oat—Avena sativa L. [grass], common vetch—Vicia sativa subsp. sativa L.)/fababean—Vicia faba L. [legume], forage rape—Brassica napus L. [brassica]) differed in functional traits related to growth, phenology, and soil water and N acquisition and use strategies. We found that grass-associated cover crops generally supported higher cash crop grain yield and profit than brassica- or legume-associated cover crops, mainly due to moderate biomass accumulation and water use and persistent groundcover. Cash crop grain yields increased by +19% and +23% following forage oat cover crop, with concomitant gains in gross margins of +96$ ha−1 and +318$ ha−1 for maize and winter wheat compared to conventional fallow. In contrast, maize grain yield following brassica-associated cover crops ranged from +8 to −21% and reduced gross margins by −229 to −686$ ha−1 relative to conventional fallow. Legume- and brassica-associated cover crops had the lowest mungbean and winter wheat grain yield and gross margins compared to conventional fallow and the added stubble. Cash crop yields were related to cover crop biomass production, biomass N accumulation, residue carbon to N ratio, and legacy impacts through effects on soil water availability at cash crop sowing. Given the additional grain yield and gross margin benefits following grass-associated cover crops, they may provide a potential alternative fallow soil water and N management option that could improve crop productivity and cropping system resilience in water-limited environments.

Agricultural systems where monoculture prevails are characterized by fertility losses and reduced contribution to ecosystem services. Including cover crops (CC) as part of an agricultural system is a promising choice in sustainable intensification of those demanding systems. We evaluated soil microbial functionality in cash crops in response to the inclusion of CC by analyzing soil microbial functions at two different periods of the agricultural year (cash crop harvest and CC desiccation) during 2013 and 2014. Three plant species were used as CC: oat (Avena sativa L.), vetch (Vicia sativa L.) and radish (Raphanus sativus L.) which were sown in two different mixtures of species: oat and radish mix (CC1) and oat, radish and vetch mix (CC2), with soybean monoculture and soybean/corn being the cash crops. The study of community level physiological profiles showed statistical differences in respiration of specific C sources indicating an improvement of catabolic diversity in CC treatments. Soil enzyme activities were also increased with the inclusion of CC mixtures, with values of dehydrogenase activity and fluorescein diacetate hydrolysis up to 38.1% and 35.3% higher than those of the control treatment, respectively. This research evidenced that CC inclusion promotes soil biological quality through a contribution of soil organic carbon, improving the sustainability of agrosystems. The use of a CC mixture of three plant species including the legume vetch increased soil biological processes and catabolic diversity, with no adverse effects on cash crop grain yield.

Based on farmer and value chain actor interviews, this comparative study of five emerging dairy clusters elaborates on the upgrading of farming systems, value chains, and context shapes transformations from semi-subsistent to market-oriented dairy farming. The main results show unequal cluster upgrading along two intensification dimensions: dairy feeding system and cash cropping. Intensive dairy is competing with other high-value cash crop options that resource-endowed farmers specialize in, given conducive support service arrangements and context conditions. A large number of drivers and co-dependencies between technical, value chain, and institutional upgrading build up to system jumps. Transformation may take decades when market and context conditions remain sub-optimal. Clusters can be expected to move further along initial intensification pathways, unless actors consciously redirect course. The main theoretical implications for debate about cluster upgrading are that co-dependencies between farming system, market, and context factors determine upgrading outcomes; the implications for the debate about intensification pathways are that they need to consider differences in farmer resource endowments, path dependency, concurrency, and upgrading investments. Sustainability issues for consideration include enabling a larger proportion of resource-poor farmers to participate in markets; enabling private input and service provision models; attention for food safety; and climate smartness.

SummaryThis article deals with cash crop production and its impact on labour relations in postcolonial African peasant agriculture. The focus is on the Lilongwe Land Development Programme (1968–1981) in Malawi. The aim of the programme was to enable African farmers to increase yields and make them shift from the cultivation of tobacco and local maize to groundnuts and high-yielding varieties of maize. The programme failed to meet its goals, because of contradictory forces set in motion by the programme itself. The LLDP enabled a larger segment of farmers to engage in commercial agriculture, which caused a decline in supplies of local labourers ready to be employed on a casual or permanent basis. Increased commercial production was thus accompanied by a de-commercialization of labour relations, which hampered the scope for better-off farmers to increase yields by employing additional labourers. By using both written and oral sources, this article thus provides an empirical case that questions the conventional view that increased cash-crop production in twentieth-century rural Africa was accompanied by a commercialization of labour relations. It concludes that the history of rural labour relations cannot be grasped by simple linear models of historical change, but requires an understanding of local contexts, with a focus on farming systems and factors that determine the local supply of and demand for labour.

SUMMARYForests are an important source of environmental services and livelihoods in Africa, thus it is important to determine potential drivers of forest loss. Over recent decades, forest cover has been declining steadily in Malawi. This paper attempts to evaluate the influence of agricultural input subsidies on forest conversion in Malawi. A two-stage regression model analysis of 2009 farm survey data from Chimaliro and Liwonde Forest reserves in Kasungu and Machinga districts, respectively, did not reveal direct evidence of policy-induced forest clearing for agricultural expansion. Instead, subsidy-induced agricultural intensification of food crops, especially maize, appeared to have reduced the rate and extent of forest clearing among households in Malawi compared with households not benefiting from subsidies. However, indirect negative impacts on forests arose due to offtake of trees to construct drying sheds for tobacco, a local cash crop. These findings have implications for designing strategies for simultaneously conserving forests while promoting food security in rural areas, and shed light on the direct and indirect effects of input subsidies.

SUMMARYAn action research process was conducted with communities in Gununo, southern Ethiopia (2000–2003), to develop alternative cropping strategies for achieving their food security and cash needs. Farmers identified three major production objectives depending on their household priorities and socio-economic status. In Group I, farmers are currently food insecure and want to produce enough food from their own farms. In Group II, they produce enough food but want to fulfil their financial needs. In Group III, farmers rely on off-farm activities and want to increase cash income. The current system mostly fulfils the nutritional requirement of Group II. Groups I and III were highly food deficit from their own farms, with production covering less than seven months per year and fulfilling <50% of the recommended daily allowances (RDA) for human nutrition. Using a linear programming optimization model, it was possible to fulfil the RDA of Group I by reallocating the cropping area of maize, sweet potato, coffee and wheat to potato, enset and kale in proportions of 50, 29 and 15%, respectively. To satisfy both financial and nutritional needs of Group II, an increase in the proportion of coffee and beans by about 29 and 7.3%, respectively, over the current land allocation was needed. This shift would triple their cash income. The cash income of Group III increased four-fold by full replacement of the cereals and root crops by coffee (48%) and teff (52%), though the total income was not enough to secure food security due to their small landholdings. In farms of Groups I and II, the shift to the suggested cropping will reduce soil erosion by about 40%, while it will have no effect on farms of Group III. This shift will reduce the quantity and quality of livestock feed, except for Group I. Moreover, it will increase the farm crop water requirement 17.5 and 37% in Groups I and III (resource poor households) and reduce it in resource rich households of Group II. These changes did not imply extra labour in any groups. Whilst this model can optimize systems for food security and cash income, its research for development value is in identifying possible intensification strategies for farming systems and their implications on the farming systems, rather than generating practical recommendations for all cropping systems.

Smallholder farming households in the Small Island Development State (SIDS) of Vanuatu have been observed to withhold family labour from cash crop production in order to contribute to participate in inter-household transfers of resources presided over by local elites, despite rising demand for income. Research throughout the Pacific suggests that inter-household transfers are principally motivated by differences in household social capital and the payment of tribute to high status households. Contributing labour to these transfers restricts the adoption of smallholder cash-crop intensification, complicating development program efforts to increase rural household incomes. This study investigates the benefits of cash-crop intensification (CCI) to cocoa growing smallholders on Malekula Island, in the north of the Vanuatu archipelago. The research presents an empirical investigation analyzing how the relationship between inter-household transfers and the adoption of labour intensive cocoa production methods, with the objective of informing the design of more effective rural development interventions in SIDS. The specific objectives of the study are to analyze: (1) the factors affecting the assignment of household labour to inter-household transfers; (2) the factors affecting the assignment of group or village labour to private households; (3) the impact of the assignment of group or village labour on household labour supply responses to on and off-farm production activities; and (4) the implications of the supply of household labour to village or group labour activities, for labour-led CCI among remote rural communities in SIDS. This study provides empirical evidence from a survey of 530 households. The analysis demonstrates that private households supply labour to village labour activities to both obtain public good benefits and as well as improve their access to shared land and labour resources in the future. The research identifies that households which are assigned village labour tend to possess higher levels of asset and social capital endowments. Households assigned village labour, tend to reallocate family labour to off-farm activities offering higher returns to their efforts. Rather than help address deficits in the supply of labour to support cash crop production at times of peak demand, smallholder households transfer labour to elite households in order to strengthen these strategic relationships and improve future access to farm inputs (land and labour). Elite households gain additional utility by using inputs of village labour to substitute on-farm family labour, releasing it to engage in off-farm employment and deliver higher income levels. This study determines that smallholder households in the study group are not sufficiently incentivised to increase their supply of labour inputs to cash crop intensification, preferring to shift surplus labour into off-farm employment and inter-household exchanges due to the higher returns to labour and potential long-run economic rewards offered by those activities. Subsequently, this study concludes that labour-led cash crop intensification programs are not the most effective method for increasing smallholder household incomes; and that national authorities and technical agencies should prioritise interventions which reduce cash crop marketing costs, facilitate improved access to income generating opportunities in off-farm employment and reduce demand for household labour from village authorities for public good production.
Thesis (Ph.D.) -- University of Adelaide, School of Global Food Studies, 2015.

Horseradish roots, due to the content of many valuable nutrients and substances with healing and pro-health properties, are used more and more in medicine, food industry and cosmetics. In Poland, the cultivation of horseradish is considered minor crops. In addition, its limited size causes horseradish producers to encounter a number of unresolved agrotechnical problems. Infectious diseases developing on the leaves and roots during the long growing season reduce the size and quality of root crops. The small range of protection products intended for use in the cultivation of horseradish generates further serious environmental problems (immunization of pathogens, low effectiveness, deterioration of the quality of raw materials intended for industry, destruction of beneficial organisms and biodiversity). In order to meet the problems encountered by horseradish producers and taking into account the lack of data on: yielding, occurrence of infectious diseases and the possibility of combating them with methods alternative to chemical ones in the years 2012–2015, rigorous experiments have been carried out. The paper compares the impact of chemical protection and its reduced variants with biological protection on: total yield of horseradish roots and its structure. The intensification of infectious diseases on horseradish leaves and roots was analyzed extensively. Correlations were examined between individual disease entities and total yield and separated root fractions. A very important and innovative part of the work was to learn about the microbial communities involved in the epidemiology of Verticillium wilt of horseradish roots. The effect was examined of treatment of horseradish cuttings with a biological preparation (Pythium oligandrum), a chemical preparation (thiophanate-methyl), and the Kelpak SL biostimulator (auxins and cytokinins from the Ecklonia maxima algae) on the quantitative and qualitative changes occurring in the communities of these microorganisms. The affiliation of species to groups of frequencies was arranged hierarchically, and the biodiversity of these communities was expressed by the following indicators: Simpson index, Shannon–Wiener index, Shannon evenness index and species richness index. Correlations were assessed between the number of communities, indicators of their biodiversity and intensification of Verticillium wilt of horseradish roots. It was shown that the total yield of horseradish roots was on average 126 dt · ha–1. Within its structure, the main root was 56%, whereas the fraction of lateral roots (cuttings) with a length of more than 20 cm accounted for 26%, and those shorter than 20 cm for 12%, with unprofitable yield (waste) of 6%. In the years with higher humidity, the total root yield was higher than in the dry seasons by around 51 dt · ha–1 on average. On the other hand, the applied protection treatments significantly increased the total yield of horseradish roots from 4,6 to 45,3 dt · ha–1 and the share of fractions of more than 30 cm therein. Higher yielding effects were obtained in variants with a reduced amount of foliar application of fungicides at the expense of introducing biopreparations and biostimulators (R1, R2, R3) and in chemical protection (Ch) than in biological protection (B1, B2) and with the limitation of treatments only to the treatment of cuttings. The largest increments can be expected after treating the seedlings with Topsin M 500 SC and spraying the leaves: 1 × Amistar Opti 480 SC, 1 × Polyversum WP, 1 × Timorex Gold 24 EC and three times with biostimulators (2 × Kelpak SL + 1 × Tytanit). In the perspective of the increasing water deficit, among the biological protection methods, the (B2) variant with the treatment of seedlings with auxins and cytokinins contained in the E. maxima algae extract is more recommended than (B1) involving the use of P. oligandrum spores. White rust was the biggest threat on horseradish plantations, whereas the following occurred to a lesser extent: Phoma leaf spot, Cylindrosporium disease, Alternaria black spot and Verticillium wilt. In turn, on the surface of the roots it was dry root rot and inside – Verticillium wilt of horseradish roots. The best health of the leaves and roots was ensured by full chemical protection (cuttings treatment + 6 foliar applications). A similar effect of protection against Albugo candida and Pyrenopeziza brassicae was achieved in the case of reduced chemical protection to one foliar treatment with synthetic fungicide, two treatments with biological preparations (Polyversum WP and Timorex Gold 24 EC) and three treatments with biostimulators (2 × Kelpak SL, 1 × Tytanit). On the other hand, the level of limitation of root diseases comparable with chemical protection was ensured by its reduced variants R3 and R2, and in the case of dry root rot, also both variants of biological protection. In the dry years, over 60% of the roots showed symptoms of Verticillium wilt, and its main culprits are Verticillium dahliae (37.4%), Globisporangium irregulare (7.2%), Ilyonectria destructans (7.0%), Fusarium acuminatum (6.7%), Rhizoctonia solani (6.0%), Epicoccum nigrum (5.4%), Alternaria brassicae (5.17%). The Kelpak SL biostimulator and the Polyversum WP biological preparation contributed to the increased biodiversity of microbial communities associated with Verticillium wilt of horseradish roots. In turn, along with its increase, the intensification of the disease symptoms decreased. There was a significant correlation between the richness of species in the communities of microbial isolates and the intensification of Verticillium wilt of horseradish roots. Each additional species of microorganism contributed to the reduction of disease intensification by 1,19%.

Abstract Conservation Agriculture (CA)-based Sustainable Intensification (CASI) practices in this study comprised minimum soil disturbance, permanent soil cover, intercropping of maize and legumes, and use of improved crop genotypes and fertilizers, and were tested on-farm in different agroecologies in northern and eastern Tanzania. The results for six consecutive years of study indicate increased adoption of CASI practices compared to the baseline year (2010). The major impacts of these practices were reduced production costs, labour savings and overall increased crop and land productivity. The average area allocated to improved maize-legume (ML) intercrop rose during the project period by 5.28 ha per household, of which 15% was under complete CASI practices. Adoption trends show that, on average, 6.5% of adopters across the study and spillover communities started adoption in the 2nd year and about 14% of farmers adopted the practices over the next 3-5 years. Demographic and human capital (family size, education, age and farming experience), on-farm CASI demonstrations, farmer to farmer exchange visits, social capital (farmers' group or a cooperative), access to input and output markets (improved seeds, herbicides, fertilizers, insecticides and equipment) and food security were found to have positive and significant effects on adoption of a range of CASI practices. These results suggest continued and long-term efforts in investments in demonstrations, institutionalizing CASI practices in NARS, and good links to input and output markets, including appropriate machinery, are necessary to achieve sustained adoption.

Improving low efficiency of phosphorus (P) use in agriculture is an imperative because P is one of the key nutrients underpinning sustainable intensification of food production and the rock-phosphate reserves, from which P fertilisers are made, are finite. This paper describes key soil, root and microbial processes that influence P acquisition with a focus on factors that can be managed to ensure optimal use of fertiliser, and development of root systems for improved P acquisition. A case study describes grasslands in southern Australia where the P-balance efficiency of production is very low, mainly because soils are P deficient and moderately to highly P-sorbing. Use of soluble P fertiliser, P-banding and soil testing to guide soil P management ensures effective use of P fertiliser. Progress towards improved P efficiency using pasture legumes with high P-acquisition efficiency is outlined. Development of a ‘whole-of-system’ understanding for effective P acquisition by roots is highlighted.