Differential exploitation of cashew - a low conflict crop - by sympatric humans and chimpanzees

Modification of natural areas by human activities mostly has a negative impact on wildlife by increasing the geographical and ecological overlap between people and animals. This can result in escalating levels of competition and conflict between humans and wildlife, for example over crops. However, data on specific crops and crop parts that are unattractive to wildlife yet important for human livelihoods are surprisingly scarce, especially considering their potential application to reducing crop damage by wildlife. Here we examine the co-utilization of a nationally important and spatially abundant cash crop, cashew Anacardium occidentalis, by people and chimpanzees Pan troglodytes verus inhabiting a forested–agricultural matrix in Cantanhez National Park in Guinea-Bissau. In this Park people predominantly harvest the marketable cashew nut and discard the unprofitable fruit whereas chimpanzees only consume the fruit. Local farmers generally perceive a benefit of raiding by chimpanzees as they reportedly pile the nuts, making harvesting easier. By ensuring that conflict levels over crops, especially those with high economic importance, remain low, the costs of living in proximity to wildlife can potentially be reduced. Despite high levels of deforestation associated with cashew farming, these findings point to the importance of cashew as a low-conflict crop in this area.

Determinants of crop diversity and composition in Enset-coffee agroforestry homegardens of Southern Ethiopia

Households in much of the tropics depend for their livelihoods on the variety and continued production of food and other products that are provided by their own farms. In such systems, maintenance of agrobiodiversity and ensuring food security are important for the well being of the population. The enset-coffee agroforestry homegardens of Southern Ethiopia that are dominated by two native perennial crops, Coffee (Coffea arabica L.) and Enset (Enset ventricosum Welw. Cheesman), are examples of such agricultural systems. This study was conducted in Sidama administrative zone of Southern Ethiopia to determine the factors that influence the diversity and composition of crops in the systems. Data were collected from 144 sample homegardens selected from four districts. Stepwise multiple regression analysis was used to relate indices of crop diversity and area share of major crops with the physical and socioeconomic factors. The study revealed that socioeconomic factors, mainly proximity to markets, affected negatively crop species richness. The production area of the main crops enset and coffee decreased with increasing proximity to market and road while that of maize and khat increased. At household level, farm size had a significant effect on area share of enset and coffee. As farm size increased the share of the cash crop, coffee increased but that of the staple, enset declined. Enset, which is the backbone of the system in terms of food security, is declining on small farms and the share of monoculture maize system is increasing. The trend towards declining agrobiodiversity, and reduction in the production area of the main perennial crops and their gradual replacement with monoculture fields could make the systems liable to instability and collapse. As these sites are high potential agricultural areas, intensification can be achieved by integrating high-value and more productive crops, such as fruits, spices and vegetables, while maintaining the integrated and complex nature of the systems.

Extraction of manganese peroxidase produced by Lentinula edodes

Lentinula edodes, commonly called shiitake, is considered a choice edible mushroom with exotic taste and medicinal quality. L. edodes grows very well and produces a range of enzymes when cultivated on eucalyptus residues. Development of appropriate experimental procedures for recovery and determination of enzymes became a widely important cash crop. In this work, enzymes produced by L. edodes were extracted using different pH buffer and determined regarding peroxidases and proteases. Lignin peroxidase (LiP) was not detected in the extracts based on veratryl alcohol or azure B oxidation. Proteases were very low while Mn-peroxidases (MnP) predominated. The optimal pH for MnP recovery was 5.0, under agitation at 25 degrees C. The oxidation of phenol red decreased after dark-colored small compounds or ions were eliminated by dialysis. The extract of L. edodes contained components of high molecular weight, such as proteases or high polyphenol, that could be involved in the LiP inactivation. L. edodes sample previously submitted to dialysis was also joined to UP of Phanerochaete chrysosporium and a total inhibition of UP was observed. (C) 2007 Elsevier Ltd. All rights reserved.

Environmental and agricultural benefits of a management system designed for sandy loam soils of the humid tropics

A sustainable management of soils with low natural fertility on family farms in the humid tropics is a great challenge and overcoming it would be an enormous benefit for the environment and the farmers. The objective of this study was to assess the environmental and agronomic benefits of alley cropping, based on the evaluation of C sequestration, soil quality indicators, and corn yields. Combinations of four legumes were used in alley cropping systems in the following treatments: Clitoria fairchildiana + Cajanus cajan; Acacia mangium + Cajanus cajan; Leucaena leucocephala + Cajanus cajan; Clitoria fairchildiana + Leucaena leucocephala; Leucaena leucocephala + Acacia mangium and a control. Corn was used as a cash crop. The C content was determined in the different compartments of soil organic matter, CEC, available P, base saturation, percentage of water saturation, the period of the root hospitality factor below the critical level and corn yield. It was concluded that alley cropping could substitute the slash and burn system in the humid tropics. The main environmental benefit of alley cropping is the maintenance of a dynamic equilibrium between C input and output that could sustain up to 10 Mg ha-1 of C in the litter layer, decreasing atmospheric CO2 levels. Alley cropping is also beneficial from the agricultural point of view, because it increases base saturation and decreases physical resistance to root penetration in the soil layer 0 - 10 cm, which ensures the increase and sustainability of corn yield.

Effects of changing water availability on land use in irrigated mountain oases of Al Jabal Al Akhdar, northern Oman

In Oman, during the last three decades, agricultural water use and groundwater extraction has dramatically increased to meet the needs of a rapidly growing population and major changes in lifestyle. This has triggered agricultural land-use changes which have been poorly investigated. In view of this our study aimed at analysing patterns of shortterm land-use changes (2007-2009) in the five irrigated mountain oases of Ash Sharayjah, Al’Ayn, Al’Aqr, Qasha’ and Masayrat ar Ruwajah situated in the northern Oman Hajar mountains of Al Jabal Al Akhdar where competitive uses of irrigation water are particularly apparent. Comprehensive GIS-based field surveys were conducted over three years to record changes in terrace use in these five oases where farmers have traditionally adapted to rain-derived variations of irrigation water supply, e.g. by leaving agricultural terraces of annual crops uncultivated in drought years. Results show that the area occupied with field crops decreased in the dry years of 2008 and 2009 for all oases. In Ash Sharayjah, terrace areas grown with field crops declined from 4.7 ha (32.4 % of total terrace area) in 2007 to 3.1 ha (21.6 %) in 2008 and 3.0 ha (20.5 %) in 2009. Similarly, the area proportion of field crops shrunk in Al’Ayn, Qasha’ and Masayrat from 35.2, 36.3 and 49.6 % in 2007 to 19.8, 8.5 and 41.3 % in 2009, respectively. In Al’Aqr, the area of field crops slightly increased from 0.3 ha (17.0 %) in 2007 to 0.7 (39.1 %) in 2008, and decreased to 0.5 ha (28.8 %) in 2009. During the same period annual dry matter yields of the cash crop garlic in Ash Sharayjah increased from 16.3 t ha-1 in 2007 to 19.8 t ha-1 in 2008 and 18.3 t ha-1 in 2009, while the same crop yielded only 0.4, 1.6 and 1.1 t ha-1 in Masayrat. In 2009, the total estimated agricultural area of the new town of Sayh Qatanah above the five oases was around 13.5 ha. Our results suggest that scarcity of irrigation water as a result of low precipitation and increased irrigation and home water consumption in the new urban settlements above the five oases have led to major shifts in the land-use pattern and increasingly threaten the centuries-long tradition and drought-resilience of agriculture in the oases of the studied watershed.

Atributos físicos do solo e produtividade de milho em resposta a culturas de pré-safra

O objetivo deste trabalho foi avaliar os atributos físicos de um Latossolo Vermelho distrófico argiloso e a produtividade de milho em sistemas de manejo que incluem plantas de cobertura cultivadas em pré-safra (setembro a novembro). Foram utilizadas, durante quatro anos, as seguintes plantas de cobertura: crotalária (Crotalaria juncea); milheto (Pennisetum americanum sin. tiphoydes); lab-lab (Dolichus lablab) em sistema de semeadura direta; e pousio cultivado em sistema de preparo convencional, antecedendo o cultivo de milho. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e quatro repetições. Amostras de solo indeformadas foram coletadas para determinações físicas e avaliou-se a produtividade de milho em área de 22,5 m². As plantas de cobertura no sistema de semeadura direta promoveram maior estabilidade de agregados e maior densidade do solo na camada superficial, sem alteração do conteúdo de água disponível às plantas. A utilização de lab-lab, em pré-safra, promoveu a menor produtividade de milho. A utilização de plantas de cobertura em pré-safra no sistema de semeadura direta de milho é viável no Estado de São Paulo.

Adubação verde e sistemas de manejo do solo na produtividade do algodoeiro

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The effects of soil moisture, field-scale toposequential position, and slope on yields in irrigated upland rice fields in Flores, Comayagua, Honduras

Rice (Oryza sativa L.) is an important cash crop in Honduras because of the rice lobby’s size, willingness to protest, and ability to negotiate favorable price guarantees on a year-to-year basis. Despite the availability of inexpensive irrigation in the study area in Flores, La Villa de San Antonio, Comayagua, the rice farmers do not cultivate the crop using prescribed methods such as land leveling, puddling, and water conservation structures. Soil moisture (Volumetric Water Content) was measured using a soil moisture probe after the termination of the first irrigation within the tillering/vegetative, panicle emergence/flowering, post-flowering/pre-maturation and maturation stages. Yield data was obtained by harvesting on 1 m2 plots in each soil moisture testing site. Data was analyzed to find the influence of toposequential position along transects, slope, soil moisture, and farmers on yields. The results showed that toposequential position was more important than slope and soil moisture on yields. Soil moisture was not a significant predictor of rice yields. Irrigation politics, precipitation, and land tenure were proposed as the major explanatory variables for this result.

Shifting cultivation stability and change: Contrasting pathways of land use and livelihood change in Laos

Rural areas in Laos are experiencing a rapid transformation from traditional rice-based shifting cultivation systems to more permanent and diversified market-oriented cultivation systems. The consequences of these changes for local livelihoods are not well known. This study analyzes the impact of shifting cultivation change on the livelihood of rural people in six villages in three districts of northern and central Laos. Focus group discussions and household interview questionnaires were employed for data collection. The study reveals that the shifting cultivation of rice is still important in these communities, but it is being intensified as cash crops are introduced. Changes in shifting cultivation during the past ten years vary greatly between the communities studied. In the northern study sites, it is decreasing in areas with rubber expansion and increasing in areas with maize expansion, while it is stable in the central site, where sugarcane is an important cash crop. The impacts of land use change on livelihoods are also diverse. Cash crop producers hold more agricultural land than non-cash crop producers, and rubber and sugarcane producers have fewer rice shortages than non-producers. In the future, livelihood improvements in the central study site may be replicated in the northern sites, but this depends to a large extent on the economic and agricultural settings into which cash crops and other development opportunities are introduced. Moreover, the expansion of cash crops appears to counteract Lao policies aimed at replacing shifting cultivation areas with forests.

Linking livelihood strategies with a regional level landscape mosaic to explore trade-offs between forest conservation and human wellbeing in a Madagascar biodiversity hotspot

The north-eastern escarpment of Madagascar contains the island’s last remaining large-scale humid forest massifs surrounded by diverse small-scale agricultural mosaics. There is high deforestation mainly caused by shifting cultivation practiced by local land users to produce upland rice for subsistence. Today, large protected areas restrict land users’ access to forests to collect wood and other forest products. Moreover, they are no more able to expand their cultivated land, which leads to shorter shifting cultivation cycles and decreasing plot sizes for irrigated rice and cash crop cultivation. Cash crop production of clove and vanilla is exposed to risks such as extreme inter-annual price fluctuations, pests and cyclones. In the absence of work opportunities, agricultural extension services and micro-finance schemes people are stuck in a poverty trap. New development strategies are needed to mitigate the trade-offs between forest conservation and human well-being. As landscape composition and livelihood strategies vary across the region, these strategies need to be spatially differentiated to avoid implementing generic solutions, which do not fit the local context. However, up to date, little is known about the spatial patterns of shifting cultivation and other land use systems at the regional level. This is mainly due to the high spatial and temporal dynamics inherent to shifting cultivation, which makes it difficult to monitor the dynamics of this land use system with remote sensing methods. Furthermore, knowledge about land users’ livelihood strategies and the risks and opportunities they face stems from very few local case studies. To overcome this challenge, firstly, we used remote sensing data and a landscape mosaic approach to delineate the main landscape types at the regional level. Secondly, we developed a land user typology based on socio-ecological data from household surveys in 45 villages spread throughout the region. Combining the land user typology with the landscape mosaic map allowed us to reveal spatial patterns of the interaction between landscapes and people and to better understand the trade-offs between forest conservation and local wellbeing. While shifting cultivation systems are being transformed into more intensive permanent agricultural systems in many countries around the globe, Madagascar seems to be an exception to this trend. Linking land cover information to human-environmental interactions over large areas is crucial to designing policies and to inform decision making for a more sustainable development of this resource-rich but poverty-prone context.

Controlling Bacterial Wilt in Muskmelon with Perimeter Trap Cropping

Perimeter trap cropping (PTC) involves planting one or more rows of a cucurbit crop that is highly attractive to cucumber beetles around the border of a main cucurbit cash crop that is less attractive to the beetles. Cucumber beetles attempting to migrate into the field are concentrated in the relatively more attractive border crop, where they can be controlled by insecticides. In New England, perimeter trap cropping using Blue Hubbard squash as the border crop around pumpkin, cucumber, or butternut squash controlled cucumber beetle/bacterial wilt with as few as one border spray of insecticide. This strategy reduced insecticide use on the main crop by up to 94 percent, nearly eliminating sprays on the main cash crop. In on-farm trials, 8 of 10 Massachusetts growers found that using perimeter trap cropping saved them money. The same tactic also effectively managed cucumber beetles on muskmelon and squash in Oklahoma.

Regional differences regarding land tenancy in rural Rwanda, with special reference to sharecropping in a coffee production area

This paper examines land tenancy systems and tenant contracts in Rwanda, with respect to socioeconomic contexts. Our research in southern and eastern Rwanda produced data suggesting that land borrowing with fixed rents has been generally practiced, and that rent levels have been low in comparison to expected revenues from field production. In the western areas of coffee production, however, the practice of sharecropping has recently appeared. This system is advantageous to landowners, as they are able to acquire half of the harvests; in addition, the fixed rent levels in this region are much higher than those of other regions. In the southern and eastern regions, because land borrowing with fixed rents has been the only tenancy pattern and rent levels have remained low, the economic situation should be interpreted in the context of a continuing traditional Rwandan land tenure system. In contrast, in the western coffee production area, the soaring of fixed rents and the emergence of sharecropping have been brought about by high pressures for land use, which were caused not only by a population increase but also by the development of cash crop production and the existence of a labor exchange system. The increase in rent levels has therefore been offset by a corresponding increase in agricultural productivity.

The role of cover crops in irrigated systems: water balance, nitrate leaching and soil mineral nitrogen accumulation

Soil salinity and salt leaching are a risk for sustainable agricultural production in many irrigated areas. This study was conducted over 3.5 years to determine how replacing the usual winter fallow with a cover crop (CC) affects soil salt accumulation and salt leaching in irrigated systems. Treatments studied during the period between summer crops were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3 m and used with the numerical model WAVE to calculate drainage. Electrical conductivity (EC) was measured in soil solutions periodically, and in the soil saturated paste extracts before sowing CC and maize. Salt leaching was calculated multiplying drainage by total dissolved salts in the soil solution, and use to obtain a salt balance. Total salt leaching over the four winter fallow periods was 26 Mg ha−1, whereas less than 18 Mg ha−1 in the presence of a CC. Periods of salt gain occurred more often in the CC than in the fallow. By the end of the experiment, net salt losses occurred in all treatments, owing to occasional periods of heavy rainfall. The CC were more prone than the fallow to reduce soil salt accumulation during the early growth stages of the subsequent cash crop.

The role of cover crops in irrigated systems: Soil salinity and salt leaching

Soil salinity and salt leaching are a risk for sustainable agricultural production in many irrigated areas. This study was conducted over 3.5 years to determine how replacing the usual winter fallow with a cover crop (CC) affects soil salt accumulation and salt leaching in irrigated systems. Treatments studied during the period between summer crops were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3 m and used with the numerical model WAVE to calculate drainage. Electrical conductivity (EC) was measured in soil solutions periodically, and in the soil saturated paste extracts before sowing CC and maize. Salt leaching was calculated multiplying drainage by total dissolved salts in the soil solution, and use to obtain a salt balance. Total salt leaching over the four winter fallow periods was 26 Mg ha−1, whereas less than 18 Mg ha−1 in the presence of a CC. Periods of salt gain occurred more often in the CC than in the fallow. By the end of the experiment, net salt losses occurred in all treatments, owing to occasional periods of heavy rainfall. The CC were more prone than the fallow to reduce soil salt accumulation during the early growth stages of the subsequent cash crop.

Economic efficiency of smallholder maize producers in Western Kenya:a DEA meta-frontier analysis

Maize is the main staple food for most Kenyan households, and it predominates where smallholder, as well as large-scale, farming takes place. In the sugarcane growing areas of Western Kenya, there is pressure on farmers on whether to grow food crops, or grow sugarcane, which is the main cash crop. Further, with small and diminishing land sizes, the question of productivity and efficiency, both for cash and food crops is of great importance. This paper, therefore, uses a two-step estimation technique (DEA meta-frontier and Tobit Regression) to highlight the inefficiencies in maize cultivation, and their causes in Western Kenya.