Browsing by Subject "Intercropping"

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Carry‐over effect of leguminous winter cover crops and living mulches on winter wheat as a second main crop following white cabbage
(2024) Stein, Sophie; Zikeli, Sabine; Möller, Kurt
Background: The direct effect of winter cover crops (WCCs) or living mulches (LMs) on a first vegetable crop has already been investigated. However, little is known about the effect on growth and yield of a second cash crop in the rotation. Aims: The aim of the study was to assess the carry‐over effect of legumes grown as WCC or LM on winter wheat as a second crop after cabbage, measured in yield and nitrogen release. Methods: Two field trials were carried out in Germany between 2019 and 2022. In the WCC trial, rye, rye with vetch, vetch, pea, and faba bean were used as WCC and compared to bare soil. The WCC biomass was incorporated before cabbage planting in late spring. For the LM trial, perennial ryegrass or white clover was used as LM during cabbage cultivation and compared to bare soil. The LM biomass was incorporated with the cabbage residues and compared to an early incorporation of LM biomass before cabbage planting. In both trials, winter wheat was sown in the fall as the second following main crop in the rotation. Results: Leguminous WCC species had significant higher wheat yield compared to non‐legumes but not compared to the control without WCC. Late incorporation of LM biomass resulted in increased wheat yield at 10.1–10.4 Mg ha −1 compared to an early incorporation before cabbage planting at 9.35 Mg ha −1 . Net N releases show that for WCC, the main effect of legume nitrogen fixation is achieved in the first crop cabbage immediately after incorporation of WCC biomass. In the case of leguminous LM, the effects of legume nitrogen fixation are of much higher relevance in the second main crop, winter wheat, due to LM biomass incorporation after cabbage cultivation. Conclusion: Therefore, we suggest to consider not only the direct but also the carry‐over effects of leguminous cover cropping in vegetable crop rotations.
Designing, modeling, and evaluation of improved cropping strategies and multi-level interactions in intercropping systems in the North China Plain
(2010) Knörzer, Heike; Claupein, Wilhelm
Adjusting cropping systems in order to increase their efficiency is a global issue. High yield and sustainability are the catchphrases of production in the 21st century, and agricultural production has to solve the balancing act between ecology and economy. Therefore, the requests for farmers, consultants and researchers are rising, and production modes are changing. Nevertheless, solutions have to be detected spatially explicit and locally adapted and accepted in order to be implemented successfully. Taking the North China Plain as an example, the productivity of arable land needs to be further increased by applying strategies to reduce or avoid negative environmental effects. Further yield increases are not possible by increasing input factors like N-fertilizer or irrigation water as N-fertilizer rates are extremely high and irrigation water is limited. However, yield increases might be possible by developing improved cropping strategies operated by cropping designs. Taking modeling and simulation tools into account back up the acceleration of research attainments and the understanding of cropping systems. The present thesis embraces the designing and modeling of such a potential cropping system, to wit strip intercropping. Thus, the main goals of the study were to analyze, design, evaluate, and in the end model intercropping. Intercropping systems are complex systems which strongly need to be designed and evaluated carefully in order to fulfill the premises of ecological and economical efficiency as well as sustainability. Multi-level interactions have to be weighted and taken into regard for evaluating datasets applicative for modeling and simulating intercropping. The main results of the study indicated, that traditional cropping systems like intercropping are widespread in China, where approximately one third of arable land is under intercropping. Reviewing cereal intercropping systems in China, the four agro-ecological regions ?Northeast and North?, the ?Northwest?, the ?Yellow-Huai River Valley? and the ?Southwest? could be classified, distinguished and described. Intercropping offers a great variation of species combination, benefits as well as challenges for cropping systems design and farmers. Carefully balanced between facilitation and competition, intercropping bears the potential of increased yield and yield stability, income security, resource use efficiency and biodiversity. Intercropping gives evidence about traditional cropping systems with the potential for future production systems under the paradigm of sustainability. Further, results from conducted field experiments indicated that border effects are the key component of intercropping performance. Nevertheless, analyzing strip intercropping statistically has peculiarities as they lack in randomization because the cropping system imposes alternating strips. Thus, spatial variability and its effect on yield were regarded differently within a geo-statistical analysis. In addition to the geo-statistical analysis, the crop growth modeling approach paid tribute to monocropping effects as well as to field border effects occurring in strip intercropping systems. Further on a model-based approach was tested to quantify multi-level interactions with special regard to changing microclimatic conditions and to optimize intercropping systems from an agronomical point of view. In comparison to other interspecific competition modeling approaches, a shading algorithm was evaluated and implemented into the process-oriented crop growth model DSSAT in order to simulate competition for solar radiation. More common in modeling mixed intercropping, a modified Beer?s law subroutine has been used instead, e.g. in APSIM. APSIM and DSSAT were compared by modeling the conducted field trials. As a result, the Beer?s law approach was not capable to model strip intercropping. In contrast, the modeling with a changed DSSAT model showed that applying a simple shading algorithm that estimated the proportion of shading in comparison to the monocropping situation and in dependency from neighboring plant height seems to be a promising approach. The results indicated that competition for solar radiation in those systems is a driving force for crop productivity but neither the most dominant nor the one and only. Resource distribution and allocation in space and time seems to be more important than the total amount of resources. Those effects have to be taken into account when simulating interspecific competition.
Development of a generic, model-based approach to optimize light distribution and productivity in strip-intercropping systems
(2014) Munz, Sebastian; Claupein, Wilhelm
Due to a growing world population, an extension of bioenergy production and the larger proportion of meat and dairy products in the human diet, with the latter particularly in India and China, the demand for agricultural products will further increase. Under decreasing resources and negative environmental impacts related to past intensification, more sustainable agricultural production systems need to be developed in order to meet the future demand for agricultural products. China, as the most populous nation with an enormous economic growth since the end of the 1970’s, plays a major role in global agricultural production. On a national level, agricultural production has to be increased by 35% during the next 20 years. However, land and water resources in China are very limited. With this in mind, the Sino-German International Research Training Group (IRTG) entitled ‘Modeling Material Flows and Production Systems for Sustainable Resource Use in Intensified Crop Production in the North China Plain’ was initiated by the Deutsche Forschungs-Gemeinschaft (DFG) and the Chinese Ministry of Education (MOE). The present doctoral thesis was embedded in the IRTG and focused, in particular, on exploring combinations of different crops produced on the same land at the same time, known as intercropping. In general, the higher productivity in intercropping, compared with monocropping, arises from the complementary use of resources (radiation, water, and nutrients) over space and time by crops that differ in physiology, morphology and phenology. The decisive question is how to optimize intercropping systems over space and time. To address this question, the present doctoral thesis combined field experiments with modeling approaches with the following aims: (i) to investigate the light availability on high temporal and spatial resolutions; (ii) to develop and validate a model that simulates the light availability for the smaller crop and accounts for the major aspects of cropping design; (iii) to determine the effect of the modified light availability on growth of maize and the smaller, shaded crop; (iv) to evaluate the plant growth model CROPGRO for its ability to simulate growth of the smaller, shaded crop; (v) to investigate the interactions between maize cultivar, cropping design and local growth conditions; and, (vi) to identify promising cropping designs and detect future research needs to increase the productivity of strip-intercropping systems. For this purpose, field experiments comprising of strip-intercropping with maize (Zea mays L.) and smaller vegetables, including bush bean (Phaseolus vulgaris L. var. nana), were carried out over three growing seasons from 2010-2012 in southwestern Germany and in the North China Plain. Growing the crops in strips facilitates mechanized management, addressing the ongoing decrease of intercropping in China due to labor scarcity in rural areas. The crop combination of maize, a tall C4-crop with erectophile leaves, and bush bean, a small, N-fixating C3-crop with a more horizontal leaf orientation, was chosen due to the large potential for a complementary resource use. Special emphasis was given on the competition for light as it plays a major role in this cropping system due to the large height differences between the crops. In this context, measurements of the photosynthetically active radiation (PAR) were conducted on high spatial (individual rows across the strip) and temporal resolutions (five-minute intervals) at the top of the bush bean canopy over a two-month co-growing period with maize. The collected data formed the basis of the simulation study towards investigating competition for light and its influence on plant growth with modeling approaches. Experimental results showed that maize yields increased in the border rows of the strip due to a higher lateral incoming radiation in years with a sufficient water supply. On average, maize yields calculated for strips consisting of 18 to four rows increased by 3 to 12% and 5 to 24% at the German and Chinese sites, respectively. Analysis of yield components revealed that yield increases in the border rows of the maize strip were mainly determined by a larger number of kernels per plant. On the other hand, shading by the taller adjacent maize induced considerable shade adaptations of bush bean, such as larger canopy dimensions and a substantially increased leaf area index due to thinner, larger leaves. These shade adaptations increased light interception, and indicated that bush bean could tolerate shading up to 30%, resulting in a total and pod dry matter similar to that of monocropped bush bean. These results suggested that there is a good potential for utilizing bush bean in strip-intercropping systems in combination with taller crops. However, higher shade levels (>40%) resulted in considerable decreases of total and pod dry matter. The high temporal and spatial resolution of the PAR measurements clearly revealed a highly heterogeneous diurnal distribution of PAR across the bush bean strip. The developed light model simulated this heterogeneity with a high accuracy under both clear and cloudy conditions. Comparison of simulated and observed hourly values of PAR across several rows within the strip of bush bean showed a root mean square error (RMSE) ranging between 47 and 87 μmol m-2 s-1 and a percent bias (PBIAS) ranging between -3.4 and 10.0%. Furthermore, the model reasonably captured the influence of different widths of the bush bean strip, strip orientations and maize canopy architecture (height, leaf area index, and leaf angle distributions). Simulations run for different latitudes and sky conditions, including different strips widths, maize canopy heights and leaf area indices (LAI), indicate that: (i) increasing the strip width might only reduce shading in the border rows of the smaller crop at lower latitudes under a high fraction of direct radiation; (ii) at higher latitudes, the selection of a maize cultivar with reduced height and LAI are suitable options to increase the light availability for the smaller crop. The present doctoral thesis presents the first approach to use the monocrop plant growth model CROPGRO to simulate growth of a legume crop grown in an intercropping system. The CROPGRO model was chosen because it provides an hourly simulation of leaf-level photosynthesis, and algorithms that account for the effects of radiation intensity on canopy dimensions and specific leaf area. CROPGRO, calibrated on data of monocropped bush bean, captured, quite well, the effects of the strongly reduced radiation on leaf area, and total and pod dry matter in the most shaded bush bean row. This indicated the models’ applicability on other intercropping systems exhibiting high levels of shading. Under a lower level of shading, cultivar and ecotype parameters had to be calibrated individually for a respective row within the bush bean strip to achieve a high accuracy of the simulations. Model simulations aided in explaining the effects arising from different shares of direct and diffuse radiation on canopy photosynthesis. This is a very important point to be further explored as diffuse radiation remains a part of light distribution and photosynthesis hardly studied in general; and, in particular, becomes more important with the increasing impact of shading. The simulation of the light availability, plant growth and yield formation within the strip of maize can be handled in a similar way as described for the smaller crop, bush bean. Modifications of the light model and a suitable plant growth model are presented and discussed. In conclusion, the main outcomes of this thesis indicate that the selection of cultivars adapted to the modified light environment have the largest potential to increase the productivity of strip-intercropped maize and bush bean. The most important characteristics of suitable maize cultivars include: (i) a high potential of kernel set; (ii) a higher water stress tolerance; and, (iii) reduced canopy height and LAI. The importance given to each of the components would subsequently be determined by the local weather and management conditions and the shade tolerance of the neighboring crop. On the other hand, to optimize yields of the smaller shaded crop, we present two options: (i) to modify the co-growing period of the intercrops temporarily to alleviate light competition during shade-sensitive growth stages; and, (ii) to modify the cropping design spatially and/or select different maize cultivars to reduce shading to the tolerated degree during the respective growth stage of the smaller crop. When the shade tolerance during the respective growth stages is determined, the light model developed can be used to optimize the cropping system temporarily and spatially. In this thesis, a promising approach, which combines a specific light partitioning model with process-oriented monocropping plant growth models, was developed. All models included in the approach can be applied at any location, and their generic nature also facilitates the integration of other crops. These attributes present a highly valuable contribution to intercropping research as their future optimization will depend strongly on the efficiency of the research efforts given: (i) the complexity of the underlying processes that determine the productivity; and, (ii) the minor share of time and money invested in intercropping research. Intercropping research has to prevent reinventing the wheel by identifying aspects in common with and already studied in monocropping systems and focus on aspects particularly inherent to intercropping systems.
The effects of leguminous living mulch intercropping and its growth management on organic cabbage yield and biological nitrogen fixation
(2022) Stein, Sophie; Hartung, Jens; Möller, Kurt; Zikeli, Sabine
In organic horticulture, living mulches (LM) are used for weed suppression and erosion prevention. In addition, leguminous LM can contribute to higher nitrogen (N) import into vegetable cultivation systems via biological N2 fixation (BNF). In order to investigate the effect of LM systems, a two- as well as three-year field experiment was conducted between 2019 and 2021 at two locations in Southwest Germany. White cabbage was intercropped with two different clover varieties (Trifolium repens cv. ‘Rivendel’, with regular growth and T. repens cv. ‘Pipolina’, a micro clover) and perennial ryegrass (Lolium perenne cv. ‘Premium’). Bare soil (with spontaneous vegetation) without intercropping was the control treatment. The second factor was the growth management of the LM: incorporation by rototilling before planting the cabbage, intercropping with the cabbage and no LM growth management, and intercropping with mulching of the LM during the cabbage growing. The results show that rototilling LM before planting the cabbage did not lead to higher weight of cabbage residues or differences in total head yield among the treatments for growth management. Intercropping without further LM growth management did not result in a reduced total head yield of cabbage compared to mulching. The micro clover ‘Pipolina’ showed no reduced competition with cabbage compared to the regular-growing white clover ‘Rivendel’. Therefore, we conclude that leguminous LM systems, regardless of growth management, can achieve high yields with sufficient irrigation and additional fertilization while increasing the inputs of N via BNF into the entire cropping system.
Effects of stand density and N fertilization on the performance of maize (Zea mays L.) intercropped with climbing beans (Phaseolus vulgaris L.)
(2022) Villwock, Daniel; Kurz, Sabine; Hartung, Jens; Müller-Lindenlauf, Maria
Maize is Germany’s most important fodder and energy crop. However, pure maize cultivation has ecological disadvantages. Moreover, its yield is low in crude protein, an important feed quality parameter. Maize–bean intercropping can potentially address both issues. A bean variety specially developed for intercropping was first introduced in 2016. Using this variety, a network of institutions conducted 13 field trials from 2017 to 2020 on four sites in Germany. We sought to determine the effects of stand density and nitrogen (N) fertilization on dry matter yield, crude protein yield, and soil mineral N content (Nmin) at harvest of intercropped vs. pure maize. The three intercropping bean densities we tested (7.5, 5.5, and 4 plants/m2) produced non-significantly different yields of dry matter or crude protein, given a maize density of 7.5–8 plants/m2. Intercropping was inferior to pure maize in dry matter yield, but non-significantly different in crude protein yield. Under neither cropping strategy were significant losses in dry matter or crude protein yield recorded with reduced compared to full N fertilization. At full fertilization, however, both pure maize systems and the 8/4 maize–bean intercrop system left significantly higher Nmin at harvest than the other variants of the corresponding system or N fertilization level and thus an increased risk of nitrate leaching. We encourage further optimization of yield performance in maize–bean intercropping, e.g., through breeding or promotion of biological N fixation via rhizobia inoculation. Furthermore, we recommend reducing N fertilization levels in maize cultivation.
Grasping the complexity of intercropping - developing and testing an integrated decision support system for vegetable production in the North China Plain
(2010) Feike, Til; Claupein, Wilhelm
This cumulative dissertation consists of six papers published, accepted or submitted to international high standard journals or books. To detect and describe the status quo of vegetable intercropping in the North China Plain (NCP), a survey was conducted from autumn 2007 to spring 2008. The results of the interviews with researchers, extensionists and farmers embedded in the first article revealed a huge variety of intercropping systems being practiced by farmers in the region. The first article furthermore elaborated farmers? underlying motives and concepts and described the knowledge transfer systems involved. When evaluating the prevailing systems against the background of the rapidly changing socio-economic frame conditions for farming in rural China, it became obvious that a great proportion of the systems practiced nowadays are prone to extinction in a long run. Therefore the second article discussed possible adjustments of the intercropping systems to fit the demands of modern agriculture, while maintaining their potential agronomic and environmental benefits. To enable mechanization, it was suggested to either adjust the machinery to the traditional row intercropping systems, or adjust the cropping system to the prevailing and available machinery. The latter approach was then followed throughout the thesis, using an agronomic modeling approach. The combination of Chinese cabbage and maize was selected, as it is a traditional intercropping system, with strong interspecific effects. In the course of this study, the two crops were strip intercropped in four field experiments at three sites in Germany and in China in 2008 and 2009. To understand, explain and predict plant behavior under the impact of complex cropping structures, crop growth models present a viable and powerful tool. However, two constrains had to be overcome within the framework of this thesis i) Chinese cabbage is not integrated in the common process-oriented crop growth models, ii) a method had to be developed to quantify resource competition and simulate intercropping. Therefore the integration of Chinese cabbage, the number one field vegetable of China, into the CROPGRO model constituted the first step for the simulation of intercropping systems in China. Two greenhouse experiments, testing crop growth and development under different temperature regimes, served as the data base for the accurate parameterization of Chinese cabbage and built the baseline for the third article. Cardinal temperatures of Chinese cabbage were identified by correlating mean relative growth rates and mean leaf appearance rates to temperature. Minimum growth temperature was identified at 0 °C, optimum temperature ranges between 14 °C and 24 °C, and maximum temperature is 34 °C. The further adjustment and testing of the model, which was executed on up to six independent data sets, is presented in the fourth article. The key to successfully simulate intercropping systems is the knowledge on changes in resource availability compared to monocropping. Therefore, a method was developed to quantify the availability of the most crucial growth factor solar radiation at any location within a Chinese cabbage strip, presented in the fifth article. The method was extended in the sixth and final article to enable the estimation of available radiation in Chinese cabbage strips of different widths. The ?environmental modifications? option of CROPGRO was employed to simulate the effects of the estimated reduction in incoming radiation in Chinese cabbage strips of different width. Simulations were conducted over up to thirty years of weather data of 12 locations throughout the NCP, and were additionally tested on different soil texture types. The results were extended over the entire NCP by linking them to a GIS-system. The developed approach constitutes a reliable decision support for the optimization of the spatial arrangements in Chinese cabbage strip intercropping systems, according to local soil and climate conditions. The described approach can be extended to develop a comprehensive decision support system that allows testing of various intercrop combinations under a wide range of climate and especially radiation environments. The presented thesis is a valuable contribution to the development of sustainable vegetable production systems in the NCP. A new method to quantify availability of solar radiation in strip intercropping was developed, which can be applied in various other intercropping systems. The integration of Chinese cabbage into CROPGRO, offers great opportunities not only for studying intercropping systems, but also for improving input levels and resource use efficiency in Chinese cabbage production in China and throughout the world. Understanding farmers? concepts and estimating the production potential of intercropped Chinese cabbage created additional value, which substantially contributes to realizing the potential of intercropping in the NCP.
Spotlight on agroecological cropping practices to improve the resilience of farming systems: a qualitative review of meta-analytic studies
(2025) von Cossel, Moritz; Scordia, Danilo; Altieri, Miguel; Gresta, Fabio
The capacity of agriculture to withstand or recover from increasing stresses (i.e., resilience) will be continuously challenged by extreme climate change events in the coming decades, altering the growing conditions for crop species. By prioritizing natural processes, agroecology seeks to foster climate change adaptation, boost resilience, and contribute to a low-emission agricultural system. Nineteen different agroecological practices using resilience-related terms and “meta-analysis”, within the subject areas ‘Agriculture and Biological Science’ and ‘Environmental Science’ were addressed, and 34 meta-analyses were reviewed to summarize the state-of-the-art agroecological adaptative strategies applied globally, and the current knowledge gaps on the role of agroecological practices in improving farming system resilience. Two main agroecological strategies stand out: i) crop diversification and ii) ecological soil management. The most frequent diversification practices included agroforestry, intercropping, cover cropping, crop rotation, mixed cropping, mixed farming, and the use of local varieties. Soil management practices included green manure, no-till farming, mulching, and the addition of organic matter. The analyzed studies highlight the complex interplay among soil, plant, climate, management, and socio-economic contexts within the selected agroecological practices. The results varied—positive, null, or negative—depending largely on site-specific factors. Developing and understanding more complex systems in a holistic approach, that integrates plants and animals across multiple trophic levels (feeding relationships, nutrient cycling, and aligning with the principles of a circular economy) is essential. More research is, therefore, needed to understand the interactions between crop diversity and soil management, their impacts on resilience, and how to translate research into practical strategies that farmers can implement effectively.
Technology adoption and farm performance in sub-Saharan Africa: evidence from Mozambique and Ghana
(2025) Asravor, Jacob; Zeller, Manfred
Increasing the productivity of agriculture in sub-Saharan Africa (SSA) is fundamental to achieving many of the Sustainable Development Goals (SDGs) in the region and, by extension, in the world. Given its importance to rural livelihoods and national economies in SSA, productivity growth in this crucial sector has the potential to stimulate broad-based poverty reduction (SGD 1) and further address the persistent food insecurity and malnutrition challenges (SDG 2) faced by the region. However, despite its potential for growth and importance to the region, productivity growth in agriculture has either stagnated or declined in SSA over the years. Efforts to tackle this persistent challenge have been focused on the promotion of improved technological packages and modern farming practices in various parts of the region. Nonetheless, adoption has mostly remained sluggish across SSA, stressing the continuing need for a deeper understanding of the underlying barriers to sustained adoption, as well as the effects of adopted technologies and farming practices on farm performance, particularly in terms of technical efficiency and technological gains. The smallholder farming contexts of Mozambique and Ghana offer distinct cases for gaining useful insights into the underlying barriers to sustained adoption of modern technologies and farming practices, as well as their effects on farm performance. Specifically, despite ongoing efforts by the Mozambican government and development partners to promote sustainable intensification practices, such as integrated soil fertility management (ISFM) practices (including mineral fertilizer, improved seeds and depending on the location, organic inputs such as manure and compost), adoption remains low among farm households. As a result, resource-poor farmers often resort to unsustainable land use practices, such as shifting cultivation, slash-and-burn agriculture, deforestation and forest degradation, along with low-cost agronomic practices like crop rotation, crop residue retention and intercropping to safeguard soil fertility. However, evidence is scarcely available on the underlying barriers to sustained adoption of promoted ISFM practices, along with the technological and technical efficiency gains associated with integrating improved versus recycled seeds with agronomic practices in Mozambique. Furthermore, one of the key challenges to technology adoption, as well as to farm performance and the long-term sustainability of agriculture, is the issue of aging farming population. This issue is particularly pressing in Ghana, where, in addition to the growing disinterest of young people in farming and an estimated life expectancy ranging from 55 – 65 years, the average age of farmers is reported to be 55. Given that the majority (73.5%) of Ghana’s population is below the age of 36, an improved understanding of how farm operators’ age influences their managerial performance and technology adoption is crucial for shaping evidence-informed policies aimed at attracting, retaining and leveraging this demographic dividend within the Ghanaian agricultural sector. From the foregoing, this thesis has three key objectives: (1) to explore context-specific evidence on the systemic barriers to sustained adoption of integrated soil fertility management (ISFM) practices by Mozambican smallholder farmers; (2) to examine the technological and technical efficiency gains associated with integrating improved versus recycled seeds with agronomic practices such as crop rotation, intercropping and crop residue management by Mozambican smallholder farmers; and (3) to assess how the age of farm operators – disaggregated into the youth, middle-aged and aged – influences their managerial performance and farm technology adoption in Ghana. The objectives of this thesis were achieved using data from both primary and secondary sources. Relying on mixed-methods research design, qualitative data were drawn using key informant interviews (KIIs) and focus group discussions (FGDs), and quantitative data via a household survey in the Central and Northern zones of Mozambique. These primary data were used to address the first and second objectives of the thesis. Overall, 32 qualitative interviews, consisting of 8 FGDs, 5 medium- and large-scale farmer KIIs and 19 expert KIIs were conducted in Mozambique. This was followed by a household survey which was conducted in the Central and Northern zones of Mozambique, involving 607 farming households who were selected through a multi-stage sampling technique. Both datasets were collected in 2022. To address the third objective of the thesis, secondary data from two nationally representative surveys in Ghana were used. These include all seven waves of the Ghana Living Standards Survey (GLSS) which were conducted from 1987/88 – 2016/17 and the two waves of the Ghana Socio-economic Panel Survey (GSPS) conducted between 2009/10 and 2014/15. While the GLSS was implemented using a repeated cross-sectional design, the GSPS followed a panel design. Overall, 24,596 farm households across Ghana were included in the sample for analysis. This thesis is organized into five chapters. Chapter 1 introduces the research topic by providing a general overview of the study within the global and sub-Saharan African contexts, followed by background information on agriculture and technology adoption in both Mozambique and Ghana. Chapter 2 explores the systemic barriers that continue to impede the sustained uptake of ISFM practices among Mozambican smallholder farmers. Chapter 3 evaluates the technological and technical efficiency gains associated with existing farmer practices of integrating improved versus recycled seeds with agronomic practices in Mozambique. Chapter 4 examines the relationship between farm operators’ age, technology adoption and managerial performance in Ghana. Finally, chapter 5 presents the conclusion of the thesis, outlines its limitations and makes recommendations for policy and future studies. Chapter 2 relies on mixed-methods research design to explore the systemic barriers to sustained adoption of ISFM practices among Mozambican resource-poor farmers. Complementing content analysis of qualitative data with descriptive analysis of data from a household survey, the findings indicate that whereas Mozambican smallholder farmers have generally recognized the compelling need for ISFM practices in high-value crop production systems such as vegetables, cotton, sugarcane and tobacco, they are reluctant to make similar investments in food crops. Instead, they adopt low-cost agronomic practices such as crop residue management, intercropping, crop rotation and shifting cultivation to safeguard soil fertility in food crop systems. Evidence further shows that the use of improved seeds, mineral fertilizers and depending on the location, external organic inputs such as manure and compost, is more prevalent among three groups of Mozambican smallholder farmers: independent vegetable producers, farmers participating in contract farming schemes and those residing in districts bordering Malawi, Zambia and Zimbabwe. Additionally, despite expressing strong willingness to invest in these inputs, farmers’ access to and use of these inputs are hindered by a complex set of systemic barriers, including unfavorable market conditions which limit profitability and intensify risk; institutional limitations such as credit constraints and human capital limitations; liquidity constraints; challenges associated with key ISFM components; an existing culture of dependency shaped by past experiences of farmers with free inputs; and entrenched perceptions among both farmers and professionals that Mozambican soils are inherently “fertile” or “virgins” and “fertilizers destroy the soil”. Given these findings, the study recommends that interventions aiming to promote sustainable land use practices like ISFM in land-abundant contexts of SSA like Mozambique, should prioritize addressing these systemic barriers to ensure sustained adoption of these practices. For instance, to raise productivity in food crop systems, agrarian interventions should adopt a holistic value chain approach which goes beyond the production phase to strengthen other critical segments of the value chain, such as extending agro-dealer networks to major production areas, as well as enhancing access of smallholder farmers to output markets that offer stable and fair prices. Again, there is the urgent need to intensify education and raise awareness among both farmers and professionals to dispel the widespread misconception that fertilizers damage the soil and on the need for farmers to implement ISFM as a package rather than in isolation. Addressing these systemic constraints holds an enormous prospect for fostering the sustained uptake of sustainable intensification practices like ISFM in Mozambique. Drawing on the findings from chapter 2, which indicates that Mozambican smallholder farmers seldom invest in purchased inputs for food crops, chapter 3 utilizes the same data to assess the technological and technical efficiency gains associated with existing farmer practices of integrating improved versus recycled seeds with agronomic practices, including crop rotation, intercropping and crop residue management in food crop systems. Relying on an endogeneity-corrected stochastic frontier and metafrontier functions to analyze the quantitative data, results from this first-stage analysis were contextualized and reinforced with evidence from the qualitative data. The findings suggest that farm households who integrated improved seeds with agronomic practices achieve a modest technological advantage (4%) relative to their peers who integrated recycled seeds with these same practices. Nonetheless, the results reveal no significant difference in technical efficiency between both groups. Instead, farm households in both groups performed these agronomic practices so poorly, such that each group could expand its total farm production by more than 50% simply by implementing these existing agronomic practices more efficiently. Consequently, the greatest potential for raising farm output in food crop systems in Mozambique lies in the capacity of resource-poor households to effectively implement these existing agronomic practices. Based on the findings, it is recommended that programs aiming to boost productivity in food crop systems in Mozambique should prioritize building the capacity of farm households to enable them implement these agronomic practices more efficiently. Encouraging resource-poor farmers to strictly adhere to recommended agronomic protocols, such as selecting the right crop mixes for intercropping and rotation, retaining crop residues on the field and using inoculants to boost nitrogen fixation in legumes can considerably enhance soil fertility and support productivity in subsequent crops. Given the increasingly aging farming population in Ghana and the urgent need for evidence-informed policies aimed at attracting and retaining the country’s growing youth population in agriculture, chapter 4 of the thesis relies on a nationally representative data from the GLSS and GSPS to evaluate how the age of resource-poor farmers influence their farm-level decision-making in terms of technology adoption and managerial performance. Drawing on a three-decade dataset from cereal-producing households and guided by the definitions of youth provided by the African Youth Charter and Ghana’s National Youth Policy, farm households were categorized into three age-based groups: youth (15–35 years), middle-aged (36–59 years) and aged (60 years and above). The findings indicate that farm operator age does not have a statistically significant effect on the type or level of agricultural technology adopted by farming households in Ghana. This finding remains robust even when the analysis is disaggregated by cereal type (i.e., maize, rice, millet and sorghum). However, the findings reveal marked differences in managerial performance between younger and older farmers, with the youth exhibiting greater managerial proficiency relative to their older peers. These findings suggest that when offered equal access to productive resources, younger farmers are better equipped to drive agricultural productivity growth in Ghana, thereby significantly contributing to the sector’s growth in the country. The study recommends for policymakers to pursue youth-focused agrarian initiatives that ensure easy access of the youth to productive resources such as land, credit and improved technologies, aimed at enabling younger farmers to leverage their potential in driving agricultural productivity gains. Overall, the findings of this thesis bring to the fore the existing systemic barriers that continue to obstruct smallholder investment decisions in sustainable land use practices like ISFM in land-abundant contexts like Mozambique and further underscore the urgent need for policy measures aimed at addressing them. It further stresses that the greatest potential for sustainably raising farm performance in low-input food crop systems in Mozambique lies in the ability of resource-poor farmers to implement these low-cost agronomic practices more efficiently. Finally, the findings highlight the need to focus on enhancing the managerial skillsets of farm operators across all age groups, especially the younger ones, rather than just concentrating on technological advancements.