The Evolution of Organic Carbon in Chinese Mollisol Under Different Farming Systems: Validation and Prediction by Using Century Model

Soil organic carbon （SOC） is an important indicator of soil degradation process. In this study, the long-term SOC evolution in Chinese mollisol farmland was simulated and predicted by validating, analyzing, processing and assorting concerning data, based on clarifying parameters of Century model need, combined with best use of recorded data of field management, observed data of long-term experiments, climate, soil, and biology, and achieved results from Hailun Agro-Ecological Experimental Station, Chinese Academy of Sciences. The results were showed as follows： Before reclamation, SOC content was around 58.00 g kg^-1, SOC content dropped quickly in early years, and then decreased slowly after reclamation. SOC content was around 34.00 g kg^-1 with a yearly average rate of 8.91‰ decrease before long-term experiments was established. After a long-term experiment, SOC would change under different farming systems. Shift farming system changed as follows： By 20-year model simulation, SOC content decreased from 34.03 to 30.19 g kg^-1, with a yearly average rate of 5.97‰; by 100-year model simulation, SOC content decreased to 24.31 g kg^-1, with a yearly average rate of 3.36‰. Organic farming system changed as follows： By 20-year model simulation, SOC content decreased slowly from 34.03 to 33.39 g kg^-1, with a yearly average rate of 0.95‰, 5‰ less than that of shift farming system; by 100-year model simulation, SOC content decreased to 32.21 g kg^-1, with a yearly average rate of 0.55‰. ＂Petroleum＂ farming system changed as follows： By 20-year model simulation, SOC content decreased from 34.03 to 32.88 g kg^-1, with a yearly average rate of 1.72‰, much more than that of organic farming system; by 100-year model simulation, SOC content decreased to 30.89 g kg^-1, with a yearly average rate of 0.96‰. Combined ＂petroleum＂-organic farming system changed as follows： By 20-year model simulation, SOC content was increased slightly; by 100-year model simulation, SOC content increased from 34.03 to 34.41g kg^-1, with a yearly average rate of 0.11‰. The above results provided an optimal way for maintaining SOC in Chinese mollisol farmland： To increase, as much as possible within agro-ecosystem, soil organic matter returns such as crop stubble, crop litter, crop straw or stalk, and manure, besides applying chemical nitrogen and phosphorous, which increased system productivity and maintained SOC content as well. Also, the results provided a valuable methodology both for a study of CO2 sequestration capacity and for a target fertility determination in Chinese mollisol.

Agroforestry for Climate Change Adaptation,Resilience Enhancement and Vulnerability Attenuation in Smallholder Farming Systems in Cameroon

The adverse impacts of climate variability and change are felt mostly by smallholder farmers and smallholder farming systems where rain-fed agriculture is predominant.Continuous dependence on rain-fed agriculture has led to declining crop productivity and crop failure in most cases as weather patterns shift which is very problematic for crop growth.Agroforestry which is one of the climate-smart,environmentally benign and agroecological practices has been found to mitigate climate change adversities while fostering adaptation,enhancing resilience and attenuating vulnerability especially in smallholder farming systems.However,in Cameroon,limited empirical research has been done to ascertain the role played by agroforestry in climate change adaptation,resilience enhancement and vulnerability attenuation.This paper which is based on an in-depth review of literature was undertaken to uncover what has been done so far in terms of empirical studies tackling the role played by agroforestry in climate change adaptation,resilience and vulnerability attenuation in Cameroon.It was found that most of the empirical studies have been carried out in one agroecological zone-the western highlands of Cameroon,showing that smallholder farmers adopt different agroforestry practices in the face of climate change with the most common being home gardens with livestock,home gardens without livestock,scattered trees on croplands,improved fallows,live fences/hedges and windbreaks,coffee-based agroforestry,cocoa-based agroforestry,apiculture-based agroforestry,fodder banks,and plantation crop-based agroforestry practices.These agroforestry practices provide a plethora of ecosystem services categorized into provisioning,supporting,regulating and cultural which play an important role towards fostering climate change adaptation,enhancing resilience and attenuating vulnerability in smallholder farming systems.From the findings uncovered by this study,it is imperative for more empirical studies to be carried out in the other four agroecological zones of Cameroon where there is a paucity of information regarding the role played by agroforestry towards fostering climate change adaptation,enhancing resilience and attenuating vulnerability in smallholder farming systems.

Transitioning from paternalism to empowerment of farmers in lowincome countries: Farming components to systems

Reasons for the initiation of farming systems/participatory approaches in non-Green Revolution（i.e., in more heterogeneous and less favourable production environments） areas in low-income countries is followed by a discussion of their evolution.Four phases are described along, with a brief description of some of the significant methods in which farmer participation has been sought, accessed and evaluated.They enabled/facilitated the evolutionary process.Although, over the last 40 years there has been a progress in making small-scale farmers much more visible in driving the agricultural research/development agenda through using the four basic stages embodied in the farming systems approach（i.e., descriptive, diagnosis, testing/evaluation and finally dissemination）, much still needs to be done.This leads on to a discussion as to some of the barriers still inhibiting true farmer empowerment and why further, such empowerment is imperative, if the agricultural challenges of this century are to be addressed successfully, namely substantially increasing agricultural productivity in an ecologically sustainable manner.Given the heterogeneity of the production environments and that many identified improvements are likely to be incremental rather than revolutionary in nature, this will require farmers＇ intimate involvement in their identification, evaluation and dissemination.Discussion in the paper recognizes that there is increasing globalization/commercialization of agriculture and is predicated on the need to consider the whole farmer-research-development continuum involving multiple stakeholders（i.e., farmers, scientists, extension workers, input/output service providers and policymakers）.Such a continuum has been explicitly recognized in the operational plans for the recently reformed international agricultural research（i.e., CGIAR） system.The paper concludes with a short discussion on the potential role of formal modelling.

Efficiency and productivity analysis of vegetable farming within root and tuber-based systems in the humid tropics of Cameroon

The study analyzes the technical efficiency of vegetable farmers in root and tuber-based farming systems within selected sites of the humid tropics of Cameroon. Multistage sampling was used to collect primary data from a cross-section of vegetable farmers drawn from eight selected sites in Santa sub division, Northwest region of Cameroon. Stochastic frontier analysis was used to estimate the technical efficiency of vegetable farmer and to examine its determinants. The results showed that farmyard manure was the most productive factor input, followed by farm equipment and labor. The mean technical efficiency level was 67%, revealing production shortfalls and indicating possibilities of significantly increasing production with the current input Jevels. Female, as well as more educated farmers were found to be significantly more efficient than their counterparts. The results also showed that farmers become less technical efficient as farm sizes become larger. Our study findings suggest that smallholder farmers＇ access to manure, farm implements, and increased women participation in vegetable farming, will produce huge payoffs in vegetable production efficiency in Cameroon.

Refining the Factors Affecting N_(2)O Emissions from Upland Soils with and without Nitrogen Fertilizer Application at a Global Scale

Nitrous oxide(N_(2)O)is a long-lived greenhouse gas that mainly originates from agricultural soils.More and more studies have explored the sources,influencing factors and effective mitigation measures of N_(2)O in recent decades.However,the hierarchy of factors influencing N_(2)O emissions from agricultural soils at the global scale remains unclear.In this study,we carry out correlation and structural equation modeling analysis on a global N_(2)O emission dataset to explore the hierarchy of influencing factors affecting N_(2)O emissions from the nitrogen(N)and non-N fertilized upland farming systems,in terms of climatic factors,soil properties,and agricultural practices.Our results show that the average N_(2)O emission intensity in the N fertilized soils(17.83 g N ha^(-1)d^(-1))was significantly greater than that in the non-N fertilized soils(5.34 g N ha−1 d−1)(p<0.001).Climate factors and agricultural practices are the most important influencing factors on N_(2)O emission in non-N and N fertilized upland soils,respectively.For different climatic zones,without fertilizer,the primary influence factors on soil N_(2)O emissions are soil physical properties in subtropical monsoon zone,whereas climatic factors are key in the temperate zones.With fertilizer,the primary influence factors for subtropical monsoon and temperate continental zones are soil physical properties,while agricultural measures are the main factors in the temperate monsoon zone.Deploying enhanced agricultural practices,such as reduced N fertilizer rate combined with the addition of nitrification and urease inhibitors can potentially mitigate N_(2)O emissions by more than 60%in upland farming systems.

Resource use efficiency, ecological intensification and sustainability of intercropping systems

The rapidly growing demand for food, feed and fuel requires further improvements of land and water management, crop productivity and resource-use efficiencies.Combined field experimentation and crop growth modelling during the past five decades made a great leap forward in the understanding of factors that determine actual and potential yields of monocrops.The research field of production ecology developed concepts to integrate biological and biophysical processes with the aim to explore crop growth potential in contrasting environments.To understand the potential of more complex systems（multi-cropping and intercropping） we need an agro-ecosystem approach that integrates knowledge derived from various disciplines： agronomy, crop physiology, crop ecology, and environmental sciences（soil, water and climate）.Adaptation of cropping systems to climate change and a better tolerance to biotic and abiotic stresses by genetic improvement and by managing diverse cropping systems in a sustainable way will be of key importance in food security.To accelerate sustainable intensification of agricultural production, it is required to develop intercropping systems that are highly productive and stable under conditions with abiotic constraints（water, nutrients and weather）.Strategies to achieve sustainable intensification include developing tools to evaluate crop growth potential under more extreme climatic conditions and introducing new crops and cropping systems that are more productive and robust under conditions with abiotic stress.This paper presents some examples of sustainable intensification management of intercropping systems that proved to be tolerant to extreme climate conditions.

A comprehensive approach for assessing the economic contribution of forage and livestock improvement options to smallholder farming enterprises

The importance of livestock production activities to improving the livelihoods of smallholder farming households and the efficiency of their underlying farming systems is increasingly recognized.A rapid increase in livestock numbers, especially beef cattle, and special purpose forages is being promoted for smallholder farms which have traditionally undertaken subsistence cropping activities or simple livestock rearing activities using low quality feedstuffs.Because limited plantings of specialized forages combined with a poor knowledge of animal nutrition are a challenge to establishing sustainable livestock enterprises, much public policy and research is now being focused on the use of new forages and improved feeding practices.A number of economic studies have suggested that specialized forage growing and livestock feeding activities can make a positive contribution to smallholder welfare.The studies have typically compared the total level of farm or household income with and without livestock activities.Little attention is given to how much the new forage or livestock activities actually contribute to or draw resources from other farm activities to assess their real economic contribution to the enterprise, and the availability of simple tools to assist in making such assessments are limited.This paper describes a simple modelling approach that was developed for an Australian Centre for International Agricultural Research（ACIAR）-supported project to explore the real as opposed to apparent economic impact of integrating improved forages and livestock within smallholder farming systems in the Red Soils region of south-central China.Application of the model is demonstrated using a simple case study of a smallholder enterprise that plans to introduce a new beef cattle rearing activity to its existing farm activity mix.The case study highlights the importance of explicitly valuing transfers of resources between different farm activities to gauge the real contribution of those activities to economic returns.

Nutrient Intake of Rural Households That Participated in a Farming System for Nutrition Study in India

Food based approach can prove effective in improving access and availability of nutrients from foods required for daily life where most of the people depend on agriculture for their livelihood. A study on feasibility of Farming Systems for Nutrition (FSN) approach was undertaken from 2013 to 2018 in a few villages of Koraput district, Odisha state and Wardha district, Maharashtra state in India. Interventions were done to increase crop diversity, intercropping of pulses and cereals, promotion of seasonal vegetables and fruits along with nutrition awareness. The endline survey showed increase in production diversity leading to improved household dietary diversity. This paper demonstrates the impact of FSN interventions on household nutrient intake. The results show that the intake of nutrients like protein, vitamin C, iron and calcium increased significantly in Koraput and all the nutrients including energy and vitamin A increased significantly in Wardha. The evidence shows that Farming System for Nutrition approach improves individual nutrient intake which in the long run can address the problem of undernutrition.

Heterogeneity in agricultural households and transition paths in southern Tibet

Smallholder livelihoods in agricultural areas in Tibet Autonomous Region,China(Tibet for short)have traditionally been based on subsistence mixed crop-livestock systems.Like many parts of China and the developing world,rural Tibet is undergoing rapid change in agricultural development,boosted by links with the off-farm sector.However,the agricultural transition process in Tibet has not been linear,is affected by policies particular to the region,and varies significantly for different categories of rural actors.This paper analyses heterogeneity of household types in agricultural areas of southern Tibet and how household structures and characteristics result in different agricultural development pathways.Data is drawn from a stratified random survey of 144 households in three townships in southern Tibet and analysed through three methods:cluster analysis,bio-economic modelling,and analysis of household perceptions and attitudes to change.The analysis allows for the identification of three key household types-semisubsistence,pluriactive and semi-commercial-organised along a continuum of intensification,commercialisation,specialisation and productivity.The study demonstrates the diversity of household farming systems in Tibet which in turn highlights the need for disaggregated analysis and tailored development policies and strategies.However,the analysis also reveals commonalities in development paths between groups,where all farm types are more interested in pursuing income and livelihood goals through an increase in productivity than through an increase in scale.Farmers in all systems choose to retain agriculture as a base from which to pursue livelihood strategies,especially through off-farm activities.Accounting for this household heterogeneity is important on several levels.First,it provides more granular detail on the process of development in rural areas of Tibet that have been very difficult to access in English literature especially in recent years.Second,the characteristics of the case study in agricultural areas of Tibet-especially the mixed agricultural-pastoral systems,high levels of seasonality,heavy state investment and increased integration with the other regions of China-may contribute to the broader agricultural development study.Third,policymakers in the central and local governments may be interested in how the household heterogeneity may affect-or be affected by-policies to increase agricultural productivity,intensify systems,change the composition of crop-livestock systems,promote rural-urban transformation and pursue environmental objectives,especially grassland degradation.

Variation of Nutrient Value in Selected Composted Farm Wastes

Smallholder farming is promoted for its environmental friendliness, assurance of food security sovereignty and conservation of indigenous knowledge. However, in actual practice, Smallholder farmers recycle farm plant waste to improve soil fertility. By so doing, they contribute to environmental pollution, emissions, and global warming. This situation is a Smallholder farmers’ challenge worldwide. One of these challenges is the inability to find cheaper sources of plant nutrients. These sources of nutrients are associated with environmental pollution, such as the release of Methane. This study focused on farm wastes (bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry) commonly produced by smallholder farmers in two farming systems of Masaka and Lyantonde Districts to explore the effects of composting and surface decomposition on nutrients contained in farm wastes by specifically: estimating baseline nutrient contents in farm wastes before disposal, determining the variation of nutrients of farm wastes managed by composting and surface decomposition and the potential source of major nutrients among selected farm wastes. Through carbon analysis, Calorimetric determination of Nitrogen and Phosphorus analysis using a block digester and UV-Visible spectrometer, Carbon, Nitrogen, Potassium and Phosphorus were determined from bean trash, maize trash, banana trash, cattle slurry, goat slurry, and pig slurry. Results revealed that goat slurry, chicken waste, maize trash and pig slurry contained more and retained more P, K, C and N, respectively, as compared to other farm wastes. Significant volumes of N and P were retained in composted materials as compared to those managed by surface decomposition.

REINTEGRATION OF CROP-LIVESTOCK SYSTEMS IN EUROPE:AN OVERVIEW

Ongoing specialization of crop and livestock systems provides socioeconomic benefits to the farmer but has led to greater externalization of environmental costs when compared to mixed farming systems.Better integration of crop and livestock systems offers great potential to rebalance the economic and environmental trade-offs in both systems.The aims of this study were to analyze changes in farm structure and review and evaluate the potential for reintegrating specialized intensive crop and livestock systems,with specific emphasis on identifying the co-benefits and barriers to reintegration.Historically,animals were essential to recycle nutrients in the farming system but this became less important with the availability of synthetic fertilisers.Although mixed farm systems can be economically attractive,benefits of scale combined with socio-economic factors have resulted in on-farm and regional specialization with negative environmental impacts.Reintegration is therefore needed to reduce nutrient surpluses at farm,regional and national levels,and to improve soil quality in intensive cropping systems.Reintegration offers practical and cost-effective options to widen crop rotations and promotes the use of organic inputs and associated benefits,reducing dependency on synthetic fertilisers,biocides and manure processing costs.Circular agriculture goes beyond manure management and requires adaptation of both food production and consumption patterns,matching local capacity to produce with food demand.Consequently,feed transport,greenhouse gas emissions,nutrient surpluses and nutrient losses to the environment can be reduced.It is concluded that reintegration of specialized farms within a region can provide benefits to farmers but may also lead to further intensification of land use.New approaches within a food system context offer alternatives for reintegration,but require strong policy incentives which show clear,tangible and lasting benefits for farmers,the environment and the wider community.

Creating adaptive farm typologies using Naive Bayesian classification

The applicability of statistical typologies that capture farming systems diversity in innovation and development projects would increase if their adaptability would be enhanced,so that newly encountered farms can be classified and used to update the typology.In this paper we propose Naıve Bayesian(NB)classification as a method to allocate farms to types by using only a few variables,thus allowing the addition of new entries to a typology.We show for two example datasets that the performance of NB classification is already acceptable when 50% of the original survey dataset to construct the typology is used for training the NB classifier.For our datasets,the performance of Naı¨ve Bayesian classification was improved when probabilities for observations to belong to multiple types were used,requiring a sample size of 30% of the survey dataset.Based on the results in this paper,we argue that NB classification is a powerful and promising statistical approach to increase the adaptability and usability of farm typologies.