Sustainable Cultural Practices Research Articles

Nitrogen dynamics and fertilisation use efficiency: carry‐over effect of crop limitation

Background and Aims Knowing the impact of cultural practices on nitrogen (N) dynamics in perennial crops is critical to promote N use efficiency. This study focused on the impact of crop regulation on the plant N dynamics, on the fruit N composition, and on the N fertilisation use efficiency. Methods and Results A large crop load gradient was set in a homogeneous plot of the grape cultivar Chasselas. Fertilisation in the form of 15N-labelled foliar urea allowed the measurement of N uptake and partitioning among plant fractions. Dry mass, carbon, and N dynamics were assessed over two consecutive seasons. Crop regulation did not affect grape N concentration at harvest. Both N uptake and root N mobilisation were reduced in response to crop regulation. Fertilisation efficiency was higher under high-yield conditions in terms of N uptake and grape N accumulation. The carry-over effects of crop regulation in the following year were highlighted. Conclusions Crop regulation strongly affects the overall plant N cycle, that is, uptake, distribution and release. Crop regulation improves must sugar concentration at harvest, while N concentration remained unchanged. The efficiency of N fertilisation varies greatly with crop load, which limits the interest of fertilisation under low-yield conditions. Significance of the Study These results contribute to the development of accurate nutrition models and sustainable cultural practices.

Evaluation of municipal sewage sludge for Arbuscular mycorrhizal fungi inoculum production

This experiment was carried out to assess the effect of soil amendment with different concentrations of municipal sewage sludge (SS) as a substrate on inoculum production of two selected arbuscular mycorrhizal fungi (AMF) i.e., Glomus mosseae and Acaulospora laevis. The experiment was a 4 × 5 factorial design with four hosts including, maize (Zea mays L.), lemon grass (Cymbopogon nardus (L.) Rendle), palmarosa (Cymbopogon martini (Roxb.) Wats.) and Sesbania (Sesbania aculeata Poir.) and the following five SS concentrations 1) no substrate, 2) 25 g, 3) 50 g, 4) 75 g and 5) 200 g pot–1) with five replications. After 90 days, the host roots and its rhizosphere soil were examined for fungal mycorrhization in terms of percent of root colonization and AMF spore quantification. Furthermore, we calculated the response of each host in terms of increase in plant height (cm), root length (cm), root, fresh shoots, and dry weight (g). Mycorrhization pattern showed moderate to abundant intraradical mycelium, extraradical mycelium, vesicles, and arbuscules in all the host plants. This pattern varied with a change in the input level of SS. The 75 g treatment obtained the maximum mycorrhization of both the AMF, while the highest input level was detrimental to AMF and host plants' survival. Among the tested hosts, lemon grass and maize had a tremendous increment in G. mosseae and A. laevis inoculum respectively. Consequently, 75 g SS with lemon grass is the most compatible host–substrate combination capable of maximum G. mosseae and A. laevis spore production and root colonization and so far, highlights the significance of an alternative, cost–effective and affordable carrier medium that can be adopted by farmers as sustainable cultural practices for on farm AMF inoculum production.

Fusarium Wilt of Bananas: A Review of Agro-Environmental Factors in the Venezuelan Production System Affecting Its Development

Bananas and plantains (Musa spp.) are among the main staple of millions of people in the world. Among the main Musaceae diseases that may limit its productivity, Fusarium wilt (FW), caused by Fusarium oxysporum f. sp. cubense (Foc), has been threatening the banana industry for many years, with devastating effects on the economy of many tropical countries, becoming the leading cause of changes in the land use on severely affected areas. In this article, an updated, reflective and practical review of the current state of knowledge concerning the main agro-environmental factors that may affect disease progression and dissemination of this dangerous pathogen has been carried out, focusing on the Venezuelan Musaceae production systems. Environmental variables together with soil management and sustainable cultural practices are important factors affecting FW incidence and severity, excluding that the widespread dissemination of Foc, especially of its highly virulent tropical race 4 (TR4), is mainly caused by human activities. Additionally, risk analysis and climatic suitability maps for Foc TR4 in Venezuela have been developed. Although currently there are no effective management solutions available for FW control, this perspective provides an overview on the influence that environmental and agricultural variables would have on FW incidence and severity, giving some insight into management factors that can contribute to reducing its detrimental effects on banana production and how climate change may affect its development.

Societal Well-Being: Embedding Nudges in Sustainable Cultural Practices

This study provides a behavior-analytic framework for a previous nudging experiment from Kallbekken and Saelen (Economics Letters 119(3), 325–327, 2013). We are concerned with achieving societal well-being from a selection-of-cultures perspective, and we call for increasing synergies between the 2 fields. The original experiment achieved a 20% reduction in food waste among restaurant customers by implementing 2 independent nudges: reducing plate size and socially approving multiple servings. We use this experiment as an example to introduce an analysis of the social contingencies (metacontingencies) responsible for not only establishing but also maintaining sustainable behavioral repertoires. We show how reducing food waste can be a simple, economic, effective example of a behavioral intervention when programmed with contingencies of cooperation. Furthermore, we generalize our model to social architectures that create and sustain cultural practices. Namely, our model addresses the long-term effects of nudging as a result of cooperation between stakeholders and how these effects are maintained by feedback loops. Whereas the aggregate effect of individual choice behavior can affect food consumption significantly, it may not suffice to change an enduring cultural practice. We argue that a behavior-analytic approach in studying complex systems informs nudging applications at the policy-making level.

The Crop Load Affects Brown Rot Progression in Fruit Orchards: High Fruit Densities Facilitate Fruit Exposure to Spores but Reduce the Infection Rate by Decreasing Fruit Growth and Cuticle Cracking

Brown rot, triggered by Monilinia spp., causes significant economic losses in fruit crop and it is mainly controlled by chemicals with inherent environmental costs. Controlling brown rot spreading by diminishing fruit susceptibility to the disease, via sustainable cultural practices, is a promising approach. In a two years experiment (2014-2015) on a peach (Prunus persica) orchard, we controlled fruit growth rates by varying the fruit load. Fruit thinning practices enhanced the fruit growth and laboratory analyses showed that, in both 2014 and 2015 samples, fast growing fruits were more susceptible to infection when in contact with conidia suspension of Monilinia laxa. In the field, brown rot infection took place in 2014 and not in 2015. In 2014, trees subject to moderate thinning intensities had the highest brown rot incidence. We argue that this is due to the fact that, for null thinning, slow growing fruits are less susceptible to the infection while, for intense thinning, even if faster growing fruits are more susceptible to infection, the lower fruits density reduces per-contact probability of infection. We compared meteorological data of 2014 and 2015 and we argue that brown rot did not spread in 2015 due to an absence of favorable conditions, summarized as the number of rainy days with mean temperature between 22 and 26 °C , in the period of fruit susceptibility.

Wine Resveratrol: From the Ground Up.

The ability of the grapevine to activate defense mechanisms against some pathogens has been shown to be linked to the synthesis of resveratrol and other stilbenes by the plant (inducible viniferins). Metabolized viniferins may also be produced or modified by extracellular enzymes released by the pathogen in an attempt to eliminate undesirable toxic compounds. Because of the important properties of resveratrol, there is increasing interest in producing wines with higher contents of this compound and a higher nutritional value. Many biotic and abiotic elicitors can trigger the resveratrol synthesis in the berries, and some examples are reported. Under the same elicitation pressure, viticultural and enological factors can substantially affect the resveratrol concentration in the wine. The production of high resveratrol-containing grapes and wines relies on quality-oriented viticulture (suitable terroirs and sustainable cultural practices) and winemaking technologies that avoid degradation of the compound. In general, the oenological practices commonly used to stabilize wine after fermentation do not affect resveratrol concentration, which shows considerable stability. Finally the paper reports on two sirtuin genes (SIRT) expressed in grapevine leaves and berries and the role of resveratrol on the deacetylation activity of the encoded enzymes.

Effects of Elicitors, Viticultural Factors, and Enological Practices on Resveratrol and Stilbenes in Grapevine and Wine

The ability of grapevine to activate defense mechanisms against some pathogens has been shown to be linked to the synthesis of stilbenes by the plant (inducible viniferins). Metabolized viniferins may also be produced or modified by extracellular enzymes released by the pathogen in an attempt to eliminate undesirable toxic compounds. Due to the important properties of resveratrol, there is increasing interest in producing foods with higher contents of this compound and higher nutritional value. The production of high resveratrol-containing grapes and wines relies on quality-oriented viticulture (suitable terroirs, sustainable cultural practices) and wine-making technologies which avoid degradation of the compound. The technique of skin extraction and enzymatic hydrolysis of glucoside forms in wine-making plays an important role in resveratrol wine concentration. Other factors affecting its final concentration and balance in wine are conditions for promoting trans-cis isomerization of aglycones, the type of yeast used, and the presence of lactic bacteria with β-glucosidase activity. In general, the enological practices commonly used to stabilize wine after fermentation do not significantly affect resveratrol concentrations, which show considerable stability.

Response of `Thompson Seedless' Grapevines to Sustainable Viticultural Practices

Consumer concerns about pesticide residues and environmental degradation are having a significant impact on the California grape industry. Growers are using a variety of practices, from integrated pest management to certified organic production, to reduce the amount of pesticides and other synthetic inputs used in vineyards. This experiment was established to test selected sustainable cultural practices in a mature `Thompson Seedless' vineyard. Treatments included in the experiment were row middle management (cultivated vs. perennial legume cover crop) and nitrogen fertilization (compost vs. synthetic). Vine nutritional status, yield, fruit composition, pruning weight, and population levels of the variegated leafhopper were monitored each season (1992–1994). In addition, efforts were expanded during the 1994 season to include assessment of spider, herbivorous mite, and beneficial arthropod densities. Conventional cultural practices (cultivation and synthetic fertilizer) produced the highest yields during the 1992 and 1993 seasons. This result may have been due to the nutritional status of vines, which was generally better for the cultivation and synthetic fertilizer treatment, especially in 1992. In 1994, significant treatment effects on yield were not observed, indicating that legume cover crop plots had become fully established. Sustainable cultural practices had little impact on growth, fruit composition, or insect pest pressure. `Thompson Seedless' grapes were grown for three seasons without the use of insecticides or herbicides. Vine diseases were managed by cultural practices and application of sulfur.

An evaluation of sustainable cultural practices for rainfed sorghum production on Vertisols in east Sudan

Cultural practice trials have been conducted in east Sudan since 1986 to demonstrate that Vertisols can be managed successfully for sorghum production using only shallow tillage (0.08 m depth) or manual no-till planting. The trials have compared tillage inputs and crop yields (outputs) of traditional manual no-till planting methods with shallow overall weeding tillage, using tractor-drawn shallow discing (one-way or wide-level discs) at three levels of manual weeding (none, once and twice). Four systems of field preparation were compared: (1) manual operations with broadcast seeds; (2) manual operations with row planting using the Saluka planting stick; (3) broadcast seed using tractor-drawn one-way discs; (4) crops planted in rows using the one-way discs fitted with a seed box. The results for three consecutive growing seasons, with very different total rainfall and distribution, show that (1) early weed control after planting has a very significant influence on grain yield; (2) shallow discing provides effective weed control and reduces the need for subsequent manual weeding; (3) crop yield is related to rainfall distribution rather than the seasonal total. These results confirm and justify the need for long-term tillage trials to clarify the temporal effect climate has upon crop yield and the local economy in semi-arid regions.