A heterogeneidade espacial induzida pelo pastejo tem sido reconhecida como um componente crucial para o manejo sustentável dos ecossistemas. Ainda assim, a maioria das intervenções realizadas pelo homem tende à homogeneização dos ambientes, inclusive no manejo dos animais. Neste estudo, foi investigado o efeito da intensidade de pastejo sobre a heterogeneidade espacial da vegetação e a criação de uma estrutura ótima para a maximização da taxa de ingestão dos animais, e suas implicações em um Sistema Integrado de Produção Agropecuária (SIPA). O experimento foi conduzido durante o inverno de 2015, no estado do Rio Grande do Sul, Brasil, em um protocolo experimental de longo prazo iniciado em 2001. Os tratamentos foram arranjados em um delineamento de blocos completamente casualizados com três repetições e consistiram em diferentes intensidades de pastejo por bovinos em pasto misto de azevém anual (Lolium multiflorum Lam.) e aveita-preta (Avena strigosa Schreb.): pastejo intenso (P10), pastejo moderado (P20), pastejo moderado-leve (P30), pastejo leve (P40) e ausência de pastejo (SP). A heterogeneidade espacial da vegetação aumentou com a diminuição da intensidade de pastejo. Maior heterogeneidade e estruturação espacial foram identificadas no mês de julho, durante o período vegetativo de ambas as espécies forrageiras. O início do florescimento ocasionou uma diminuição na dependência espacial e um incremento na heterogeneidade abaixo da escala de observação. P10 apresentou dossel homogêneo espacialmente ao longo de todo o ciclo de pastejo, composto em sua maior parte por uma vegetação excessivamente pastejada (<10 cm). P20 apresentou maior participação de alturas ótimas para a maximização da taxa de ingestão (15 a 29,99 cm) ao longo do ciclo de pastejo. Com o aumento da intensidade de pastejo, aumentaram também a carga animal (CA, P<0,05) e o ganho de peso vivo por área (GPV, P<0,05). A intensidade de pastejo moderada (P20) apresentou maior ganho médio diário (GMD, P<0,05) quando comparada ao pastejo intenso (P10), não diferindo, no entanto, de P30 e P40. Sendo assim, a utilização de intensidades de pastejo moderadas constitui na melhor alternativa para conciliar produtividade e conservação ambiental em SIPA. / Spatial heterogeneity induced by grazing has been recognized as a crucial component to the ecosystems sustainable management. Even so, most of the interventions made by humans tend to homogenize the environments, including animal management. In this study, we investigated the effect of grazing intensity on vegetation spatial heterogeneity and creation of an optimal structure for maximizing animals intake rate, and the implications for an Integrated Crop-Livestock System (ICLS). The experiment was carried out during winter 2015, in the Rio Grande do Sul state, Southern Brazil, in a long-term experimental protocol implemented in 2001. Treatments were arranged in a randomized complete block design with three replicates and consisted of different grazing intensities by steers on Italian ryegrass (Lolium multiflorum Lam.) and black oat (Avena strigosa Schreb.) mixed pastures: intensive grazing (P10), moderate grazing (P20), moderate-light grazing (P30), light grazing (P40) and absence of grazing (NG). Vegetation spatial heterogeneity increased with decreasing grazing intensities. Greater heterogeneity and spatial dependence were identified in July, during both forage species growing season. The flowering initiation caused a decrease in spatial dependence and an increase in small scale spatial heterogeneity (nugget effect). P10 showed a spatially homogeneous canopy throughout the grazing cycle, composed mostly by an excessively grazed vegetation (<10 cm). P20 showed higher participation of optimal heights for maximizing the intake rate (15 to 29,99 cm) throughout the grazing cycle. Increasing grazing intensity also increased stocking rate (SR, P<0,05) and liveweight gain per area (LWG, P<0,05). Moderate grazing intensity (P20) showed higher average daily gain (ADG, P<0,05) compared to intensive grazing (P10), without difference, however, from P30 and P40. Therefore, the utilization of moderate grazing intensities is the best alternative to reconcile productivity and environmental conservation in ICLS.

No description available.

Soil erosion is one of the major threats to soil functions in many parts of the world. To- day’s challenge is to adapt agriculture practices in order to reduce soil erosion and at the same time consider local conditions. One solution that has been proposed for hilly regions is agroforestry, a land-use system in which woody perennials are grown on the same piece of land as agricultural crops and/or animals. This Master thesis was conducted in two sites in Northwest Vietnam, in Son La and Dien Bien province. Northwest Vietnam is characterized by a mountainous landscape and agri- culture is practiced in the hills, often as monoculture of sole crops. This type of land use in combination with seasonal large high-intensity rains aggravates soil erosion. In this study, agroforestry (AF) practices’ capacity for erosion control was evaluated, and compared to sole crops of the dominant species in the area. An Experimental Trial in form of replicated field plots of block design and a larger Exemplar Landscape were used. The Experimental Trials and the Exemplar Landscape had two treatments, one AF system and one control treatment with sole crops. The AF system included crops, fruit trees and grass strips with the aim to form terraces naturally. To evaluate the AF’s capacity for erosion control, average amount of lost soil was es- timated in the Experimental Trials by three methods; erosion traps, erosion pins (both field methods) and a WEPP model. Another function of the erosion pins was to evaluate the movement of soil along the hillside. Soil texture, structure, color and signs of bio- logical activity were analyzed from soil profiles. Soil samples were also taken for soil analyzes of parameters needed for calculations and the WEPP model. A method was also developed to assess the terrace formation over a longer a time scale. Results of this study showed that agroforestry in combination with grass strips perform well in decreasing soil loss in the Son La study site. The soil loss in Son La was found to be 43% less two years after establishment compared to the sole maize system figuring as the control. The results also showed that grass strips have the ability to start forming terraces already one year after establishment of the Experimental Trial in both study sites. The terraces showed further development several years after the establishment at land- scape level.

MSCAGR (Soil Science) / Department of Soil Science / Soil resilience is the ability of a soil to recover its function or capacity after applied stress such as crusting. Some soils have high potential for recovery while others have poor resilience. Soils with poor resilience are much more vulnerable to degradation. Many soils in South Africa are susceptible to crust formation, which affects many soil surface properties and processes and hence productivity. The objectives of this study were to demonstrate how soil resilience to crust formation is affected by conventional tillage and conservation agriculture in selected soils in South Africa. Soil samples were collected from four different soils (Hutton, Shortland, Glenrosa and Dundee) using PVC pipes with the length of 20 cm and diameter of 5cm and scanned using micro xray computed tomography for total pores. Total porosity from Luvisols, Ferrosols, Leptsols and Fluvisols under both conventional tillage and conservation agriculture was used to find soil resilience index. Soil crusting was influenced by both soil texture and clay mineralogy. The dominance of kaolinitic mineral caused the soil to be more stable as compared to soil dominated by quartz. Luvisols, Ferrosols and Leptsols were more stable and had aggregate stability of 57%, 69,5% and 32,7%, respectively. On the other hand, Fluvisols had poor aggregate stability with the value of 14,2%. Total porosity was in the order of 34,3%>32,2%>23,5%>16,3% for Ferrosols, Luvisols, Leptsols and Fluvisols, respectively. Soil crusting influenced the total porosity. Tillage practices had influence on soil crust formation hence, total porosity of the soils. Total porosity was higher under conservation agriculture as compare to conventional tillage. Resilience total porosity was in the order of 37,5> 23,9> 4,1> -30,1 on Luvisols, Ferrosols, Leptsols and Fluvisols, respectively. Soil resilience to crust formation was influenced by tillage practices. Soil resilience of Luvisols, Ferrosols and Leptsols can be achieved through conservation agriculture however, soil resilience of Fluvisols can be achieved through conventional tillage. / NRF

In most of the developing countries, small scale farmers (SSFs) are usually the primary agricultural producers of staple crop. Furthermore, they highly depend on rainfall for their rain-fed agricultural production. SSFs have limited capacity to adapt to extreme climate variability, thus rendering them to be among the most vulnerable to climate change. Some recent studies show that agricultural production and productivity is being negatively impacted by climate change and variability in most parts of Southern Africa. This is likely to continue for decades into the future, unless corrective or adaptation measures are implemented to reduce the impact on agriculture. Conservation Agriculture (CA) is one of the climate change and weather variability adaptation measures being promoted for SSFs in Kalomo District of Zambia. CA is not only being promoted to improve production and productivity for food security for the majority rural population, but also as an adaptation measure for sustainable agricultural production. The present study analysed the CA practices being promoted in Kalomo district of southern Zambia and the associated challenges in the management and implementation, as well as, how best these challenges can be addressed. Semi-structured interviews and literature review were used as methodologies of data collection for the study. The findings of the study indicate that among the three principles of CA, minimum tillage is mostly practiced compared to crop rotation and retention of crop residue. Within minimum tillage, ripping was found to be practiced on a larger scale compared to making basins. The major challenges include planning and human resource development, financial resource and policy constraints and cultural barriers to adoption of CA.

No description available.

Much of Haitian agriculture is characterized by subsistence farming systems on eroded and nutrient-poor soils. Implementation of Conservation Agriculture systems has proven effective at improving soil quality and crop yield in many areas of the world, including areas similar to those in Haiti. While most Haitian smallholder farmers are highly resource-limited and adoption of new technologies is limited, these farmers are known to adopt new crops and practices if benefits that outweigh risks are demonstrated. Cover crops that help provide soil cover and increase nutrient mineralization are one of the most potentially beneficial changes that could be made on most smallholder farms. However, before specific cover crop recommendations can be made, their potential benefits need to be quantified. One field experiment in the summer of 2013 assessed decomposition rates and nutrient mineralization from common cash crops and two potential cover crops either on the soil surface or buried at 15 cm. The relative difficulty and expense of conducting these types of field trials led to the development and assessment of a laboratory-based system that could be used to simulate plant residue decomposition and nutrient release under controlled conditions. Additional benefits of a laboratory-based study include the ability to test significantly more treatment combinations than would likely be possible under field conditions and to control nearly all other experimental variables, other than the desired treatment comparisons. / Master of Science

L’intensificazione sostenibile delle pratiche agricole rappresenta un paradigma per il passaggio da sistemi agricoli tradizionali all’applicazione di tecnologie e tecniche moderne per la produzione agricola. A livello globale si è diffuso l’interesse verso il modello di Agricoltura Sostenibile (AS), in vista di alcuni problemi che possono minacciare la sicurezza alimentare mondiale: crescita della popolazione mondiale, cambiamenti nella domanda delle produzioni agricole, percentuale elevata di persone sottonutrite, cambiamenti climatici, diminuzione delle risorse naturali. Il progetto “Produzione di cibo appropriato: sufficiente, sicuro, sostenibile”, ancora in corso, lavora per raggiungere alcuni scopi: (1) rilevare e valutare la disponibilità quantitativa e qualitativa degli alimenti destinati al consumo umano, (2) proporre nuovi sistemi di produzione agro-zootecnica, (3) sviluppare tecniche appropriate per processare e conservare gli alimenti, al fine di ottenere uno stato di sicurezza alimentare e sostenibilità ambientale ed economica. L’obiettivo generale di questo lavoro è quello di mostrare quali sono le possibili alternative ai sistemi agricoli tradizionali, sia nei Paesi Sviluppati sia in quelli in Via di Sviluppo, al fine di aumentarne l’efficienza e diminuirne gli impatti sull’ambiente, aumentando lo stato globale di sicurezza alimentare. Per i Paesi in Via di Sviluppo l’attenzione si concentra sulle pratiche di sviluppo rurale integrato, al fine di implementare quantitativamente la produzione alimentare e, conseguentemente, la sicurezza alimentare, preservando nel contempo l'ambiente. Per i Paesi Sviluppati, in cui i rendimenti agricoli sono già potenzialmente molto elevati, l’attenzione viene focalizzata sul migliorare la produttività del suolo, riducendo gli input esterni e le emissioni di gas ad effetto serra, attraverso l’adozione di sistemi agricoli conservativi. / Sustainable intensification of agricultural practices represents a paradigm shift from traditional farming systems to the application of modern technologies and techniques to crop production. At global level it has been widespread interest towards Sustainable Agriculture (SA) model, in view of some issues that will may threaten the world food security: growing world population, changes in agricultural product’s demand, high prevalence of undernourishment, climate changes, decreasing of natural resources. The project “Production of proper food: sufficient, safe, sustainable" is still working to achieve some purposes: (1) to detect the availability quantity and quality of food for human consumption, (2) to propose new agro-livestock production systems, (3) to develop appropriate techniques for processing and storage of foodstuffs, in order to achieve food security, environmental and economic sustainability. The objective of this work is to show what are the possible alternatives ways at traditional agricultural systems, both in Developed and Developing Countries, in order to increase the efficiency and to decrease the impacts on the environment, raising a global condition of food security. For Developing Countries the attention is focused on integrated rural development practices in order to implement food production and the state of food security, while preserving the environment. For Developed Countries, in which yields are already potentially higher, the attention is focused on enhance soil productivity while reducing external farming input and greenhouse gases emission by the adoption of conservation agricultural systems.

O ambiente de terras baixas no sul do Brasil é predominantemente explorado com a cultura do arroz irrigado. Baseado em um sistema agrícola pouco diversificado, é comum o uso sucessivo das mesmas áreas ano após ano, com práticas de manejo que envolvem o revolvimento do solo. Isto acarreta em prejuízos tais como a degradação do solo e recursos naturais, além de recorrente baixa rentabilidade da atividade. O cultivo de espécies forrageiras hibernais, associado com o não revolvimento do solo, pode trazer melhorias ao sistema produtivo, seja com seu uso como plantas de cobertura ou com o pastejo animal. O objetivo deste trabalho foi avaliar os benefícios e potencialidades que a utilização destas espécies podem proporcionar e, para tanto, dois estudos principais foram realizados. O primeiro, conduzido no município de Cachoeirinha, RS, avaliou o estado de agregação e o incremento do teor de carbono orgânico do solo, comparando cultivos sucessivos de arroz irrigado em um experimento de longa duração. Os tratamentos foram um sistema manejado na forma convencional, com revolvimento do solo, e outros três sob semeadura direta, com coberturas de: azevém, cornichão e vegetação espontânea. Os resultados indicaram que, na camada de 0 a 5 cm de profundidade, os tratamentos sob semeadura direta apresentaram maiores teores de carbono orgânico e agregação do que o convencional. Já na camada de 5 a 10 cm, para os agregados, o tratamento azevém se destacou em relação aos demais. O segundo estudo foi conduzido no município de Cristal, RS. Foram avaliadas a produção animal e de forragem durante três anos no período hibernal, em diferentes combinações de sistemas integrados de produção agropecuária (SIPA). Os cultivos estivais trataram-se de arroz irrigado, soja, capim sudão e campo de sucessão, enquanto as pastagens hibernais consistiram de azevém e consórcios desta espécie com trevo branco e cornichão. Os resultados confirmaram a adaptabilidade destas espécies forrageiras ao ambiente de terras baixas e demonstraram as potencialidades que a exploração pecuária possui, sendo necessários, porém, novos estudos para o melhor ajuste do manejo das áreas. Por fim, foi realizado um terceiro estudo, comparando a relação entre a massa de forragem e altura de pastos hibernais em SIPA conduzidos em terras altas com SIPA em terras baixas. A relação no ambiente de terras baixas é menor, corroborando a necessidade de maiores estudos neste ambiente, visto que as alturas ótimas preconizadas para o manejo do pasto se originam de estudos conduzidos em terras altas. / The lowland environment in Southern Brazil is predominantly explored with the irrigated rice crop. Based on a very low diversified system, in such environment is very common the successive use of the same areas year after year, with management practices that involve soil tillage. This leads to damages such as the degradation of soil and natural resources, in addition to recurrent profitability problems. The insertion of winter pasture species associated with the no-till, as cover crops or for animal grazing, may bring improvements to the system. The objective of the current work was to evaluate the benefits and potentialities that the utilization of such plants can provide. For this, two main studies were performed. The first, conducted in the Cachoeirinha County (Rio Grande do Sul State – RS), evaluated the soil aggregation status and its organic carbon content, by comparing successive irrigated rice croppings in a long-term experiment. The treatments consisted of one system under conventional soil tillage and three others under no-till, being the treatments the following cover crops: Italian ryegrass, birdsfoot trefoil and spontaneous vegetation. The results indicated that, in 0 to 5 cm soil layer, the treatments under no-till presented higher organic carbon contents and greater aggregation, as compared to the conventional system. In the 5 to 10 cm soil layer, the treatment with Italian ryegrass has its aggregation highlighted among the others. The second study was conducted in the Cristal County (RS). The animal and pasture production was evaluated during three years in the winter season, under different combinations of integrated crop-livestock systems (ICLS). The summer croppings were irrigated rice, soybean, Sudan grass and a succession field (native pasture), while the winter pastures consisted of Italian ryegrass and its mix with white clover and birdsfoot trefoil. The results confirmed the adaptability and potentiality of such pasture species and livestock exploration in the lowland environment. However, it is needed further studies for a better management adjustment of the areas. Finally, a third study was performed, comparing the relationship between forage mass and winter pasture height in ICLS conducted in highland and lowland. It was demonstrated that in lowland such relationship is lower, corroborating the necessity of more studies in these conditions, because the optimum heights preconized for pasture management are originated from studies conducted in highlands.

<p>The aim of the research was to identify what female and male farmersthink are the best strategies to enhance the role of conservation farming as a buffer against social, economic and environmental hazards, and a means of ensuring livelihood sustainability and food security. The study also aimed at coming up with information useful to policy and other decision makers on how to improve adoption of these technologies. The empirical component of the research included a questionnaire survey of one hundred and fifty two(152) selected households in one identified ward in Insiza District, focus group discussions and semi-structured interviews with key informants and in-depth interviews of individual male and female members of a few selected farming households from the sampled population. The desktop portion of the study used secondary data from non-governmental organizations (NGOs), government and other stakeholders involved in conservation farming. Collected data was then disaggregated by gender and analyzed using the Statistical Package for the Social Sciences (SPSS). Perception statements that emerged as significant in chi-square tests of independence were be subjected to factor analysis and weighted factor scores from factor analysis were then used as independent variables in binary logistic regression analysis. The study concluded that both practising and non practising farmers were of the opinion that conservation farming was good though they indicated that information on conservation farming was not readily available The study found out that most farmers agreed on the possible positive effects of CA in addressing livelihood challenges effected by hazards such as HIV and AIDS and environmental hazards such as declining soil fertility but it had is labour intensive therefore is not suitable for people affected and infected by HIV and AIDS...</p>