SESSION I - CROP MANAGEMENT
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Lesson 1
Lesson 1
Agro-Ecosystem functioning in drylands, with special emphasis to cactus pear
by Francesco G. S. Angeletti, Irma Terracciano and Sergio Saia
Introduction to Lesson 1
Introduction to Lesson 1
Covering about 41% of the world’s surface, drylands can be found in all continents and are characterised to a greater or lesser extent by low water availability, high solar radiation and soils typically low in organic matter and nutrients and prone to erosion and desertification. Based on the annual average precipitations and of the potential of evapotranspiration, drylands can be classified in three main typologies: semi-arid drylands, arid drylands and hyper-arid drylands.In semi-arid drylands precipitations range between 800 and 300 mm per year and are mainly concentrated in winter. These areas permit rain-fed agriculture with more or less sustained levels of production as well as sedentary livestock production. In arid drylands precipitations vary from 300 to 100 mm per year and are characterised by sparse native vegetation consisting of annual and perennial grasses, shrubs and small trees. The main farming activity is pastoralism while farming becomes possible only with irrigation or growing drought resistant plants. The hyper-arid drylands show annual rainfall lower than 100 mm and sometimes and rains may also not come for several years. Vegetation is absent or consists in scattered shrubs, while only nomadic pastoralism can be practised. Despite the harsh environmental conditions, drylands are characterised by unique landscapes and host a high diversity in fauna, vegetation and micro-organisms. They are also inhabited by nearly 2 billion of people, predominantly involved in agriculture. Most of the farming systems are characterized by mixed crop - livestock and pastoral system with low productivity.Water scarcity and reduced soil fertility are probably the most limiting factor for farming activity. To cope these issues, local farmers rely on different strategies. As an example, water-harvesting systems are commonly used to increase water availability. Soil fertility can be improved through the application of manure and crops residues, by growing leguminous and applying the crop rotation. Although its beneficial effects on soil fertility, green manuring results harder to apply for small-farmers due to the low yield and the necessity to produce feed and food. Growing stress-tolerant plants is another key aspect in ensuring sustainable production. In the arid and semi-arid areas of the Mediterranean basin, winter cereals like barley, wheat, and oat, and different legumes as lentil, chickpea, field bean, sweet-vetch and berseem trefoil are the main crops cultivated by small-farmer to ensure forage and grain production. However, also perennials like grapevine, olives tree, fig tree and plants belonging to the genus Opuntia are important for local agroecosystem. Tree and shrub species are important not only for the products they generate, but also for the ecosystem-services they carry out, as in example the protection of crops and livestock from the harmful atmospheric effects, the carbon stock increase and the biodiversity promotion. Opuntia plants are particularly well adapted to drought and high temperatures and grow easily in low fertility soils. They generate income for local farmer and offer nourishment and protection to fauna, contemporarily acting an important role in soil fertility protection and restauration. There are many Opuntia species but Opuntia ficus-indica, commonly known as cactus pear, is the only one cultivated in the Mediterranean basin, where it is used for a variety of purposes.
Golla B (2021) Agricultural production system in arid and semi-arid regions. J Agric Sc Food Technol 7(2): 234-244. DOI: 10.17352/2455-815X.000113Maestre, F.T., Biancari, L., Chen, N. et al. Research needs on the biodiversity–ecosystem functioning relationship in drylands. npj biodivers 3, 12 (2024). https://doi.org/10.1038/s44185-024-00046-6Yu, X., Liu, Y., Niu, S., Zhao, W., Fu, C., Chen, Z. (2024). Structure, Functions, and Interactions of Dryland Ecosystems. In: Fu, B., Stafford-Smith, M. (eds) Dryland Social-Ecological Systems in Changing Environments. Springer, Singapore. https://doi.org/10.1007/978-981-99-9375-8_3
Golla B (2021) Agricultural production system in arid and semi-arid regions. J Agric Sc Food Technol 7(2): 234-244. DOI: 10.17352/2455-815X.000113Maestre, F.T., Biancari, L., Chen, N. et al. Research needs on the biodiversity–ecosystem functioning relationship in drylands. npj biodivers 3, 12 (2024). https://doi.org/10.1038/s44185-024-00046-6Yu, X., Liu, Y., Niu, S., Zhao, W., Fu, C., Chen, Z. (2024). Structure, Functions, and Interactions of Dryland Ecosystems. In: Fu, B., Stafford-Smith, M. (eds) Dryland Social-Ecological Systems in Changing Environments. Springer, Singapore. https://doi.org/10.1007/978-981-99-9375-8_3
Video Lesson
Video Lesson
In Depth
In Depth
Everything you need to know about drylands https://thinklandscape.globallandscapesforum.org/50717/everything-you-need-to-know-about-drylands/
The problem of agriculture in the semi-arid regionshttps://www.fao.org/4/t0321e/t0321e-08.htm#TopOfPage
Rural landscape in the Mediterranean basin
Olive tree cultivation on a hill
Olive orchard during the summer
A farmer herding her sheep grazing in an olive orchard
Lesson 2
Lesson 2
Crop management under arid areas to increase the potential, attainable and actual yields
by Giorgia Liguori and Sonia Labidi
Introduction to lesson 2
Introduction to lesson 2
Cactus pear (Opuntia ficus-indica) is considered among the most adapted plant species to semi-arid and arid conditions characterized by high water deficits and repetitive droughts. To enhance the productivity of this species in such harsh conditions, the good management of production techniques is necessary. Firstly, we must master the technique of plantation to ensure a good growth of plants but also effectively control erosion and valorize the low quantity of precipitation. For these reasons, in arid region a distance of 5.0 m between the plants and on the line is recommended to have about 400 plants/ha.After the operation of plantation, we must be careful with the weeding operation because young plants are very sensitive to weeds at this stage of growth. The weeding can be done manually (for small areas), mechanically or chemically. To enhance the production of cactus, the pruning of the plants is essential and it consists in balancing the shape, lightening the branches and stimulating flowering (video linked). Concerning the fertilization, it depends basically on the fertility of the soil (amounts of organic matter and mineral elements) and the kind of production: fruits or cladodes. For fruits, a quantity of 20 to 30t/ha of organic manure, 100kg of phosphorus and 20kg of nitrogen per hectare is recommended before planting followed by 50 to 100kg of nitrogen and 50kg of phosphorus per hectare each year, after plantation. For cladodes production, an annual quantity of nitrogen (160kg/ha) to enhance vegetative growth is preconized. Biological fertilization based on beneficial microorganisms like mycorrhizal biofertilizers (photo 1 b) and bacterial ones is an advised technique to improve the sustainability of Opuntia production. In addition to good fertilization management, the irrigation of cactus field seems to be an effective solution to increase fruits and cladodes yields, despite the high resistance of this species to water stress. The most critical period for irrigation is during the time of issuing the flower buds, because the fruits obtained will have large sizes, fleshy, juicy and very sweet.Moreover, to improve the quality of the fruit and expand the period of production, an Italian technique called “Scozzolatura” is largely practised and it consists in eliminating, between mid-May and mid-June (from 2 weeks before full bloom to 2 weeks after full bloom), the flower buds and young cladodes emitted in spring, permitting the apparition of a second wave of flowering 30 to 40 days after. This operation offers the possibility to farmers to improve their income given the out-of-season production of fruits.
Video Lesson
Video Lesson
Lesson 3
Lesson 3
Intercropping of perennials with annual crops
Intercropping of perennials with annual crops
by Francesco G. S. Angeletti, Irma Terracciano, Laura Righetti, Daniela Pacifico and Sergio Saia
Introduction to lesson 3
Introduction to lesson 3
Intercropping consists of growing two or more crops on the same field contemporarily. Intercropped plants normally have different abilities to use resources available for growth, which leads to yield advantages and increased stability compared to a single crop in a low input system.There are several types of intercropping but generally is possible to classify them based on the design (mixed, row, strip, or relay), duration (temporary or permanent) and management (species combination, plant density, harvesting time, etc). Intercropping can be realised also associating perennials plants with annual crops. When firsts are planted in rows creating alleys within seconds grew, we talk about “alley cropping”.Cactus pear is a perennial arid-resistant plant well-suited to be associated in alley cropping for fruit, vegetables, forage, and grain production in the Mediterranean region. Main benefits are:- Improvement of production and economic return;- Reduction of soil erosion and nutrients loss;- Enhanced carbon sequestration;- Promotion of biodiversity.Cactus pear acts as barrier against wind improving within-row crops production by reducing water loss and increasing water availability in soil. Moreover, intercropped cereals can stimulate an increase in the number of cactus fruits and cladodes while integrating forage legumes in cactus orchard provides protein supplement for livestock, and increases Nitrogen availability in the system.Soil erosion and nutrients loss can be effectively countered by cactus pear-annual crop association: cladodes break down wind action and enable through shading the development of the annual crop sown between the rows of cactus pear, thus protecting the otherwise exposed soil from pouring rain and water run-off.In the rainy season, cactus pear produces great amounts of small roots which die in the dry period. This improves soil organic matter content and consequently its fertility.As a perennial, the inclusion of cactus pear in cropping systems is an important tool to enhance long-term carbon sequestration.Moreover, cactus pear promotes biodiversity by providing nourishment and shelter to animals and through facilitation interactions to other plants.
Video Lesson
Video Lesson
Lesson 4
Lesson 4
Other agronomic aspects
by Francesco G. S. Angeletti, Irma Terracciano, Laura Righetti Daniela Pacifico and Sergio Saia
Introduction to lesson 4
Introduction to lesson 4
Prickly pear can grow in low fertility soils and in limited water availability conditions. Despite its good adaptability to harsh environmental conditions, when cultivated for obtaining high yields, an adequate management must be implemented. Irrigation, soil salinity and biotic stress management are among the main aspects that farmers should pay attention.Prickly pear shows higher tolerance to drought and better water use efficiency (WUE) compared to many other crops, surviving even with only 200 mm year-1 of water. However, to ensure high yield and good fruit quality, between 300- and 600- mm year-1 are required. For this reason, in areas where rainfall is less than 300 mm year-1 irrigation become necessary. Since in the Mediterranean region the rainy period coincides with the winter, irrigation should be acted during the summer. Moreover, adequate water supplies must be ensured during flowering: a lack of water in stage, will negatively affect fruit quality. In contrast, 2-3 irrigations of 30-50 mm each can increase fruit size and pulp proportion.Cactus pear is sensitive to salts dissolved in soil and high concentration can affect fruit productions as well as the plant growth, by reducing both the shoots and the roots. Due to the disintegration of the rocks, mineral salts are naturally present in the soil, and are at the basis of its chemical fertility. However, in consequence of environmental and anthropic factors, the concentration of some salts can rise beyond values tolerable by plants.The intensive exploitation of fresh water for agricultural, industrial, and domestic purposes has led over the years to a lowering of the groundwater level, which induces marine water intrusion towards freshwater basins. As a result of this phenomenon, the water used in agriculture for irrigation often has an excessive content of salts. For this reason, water quality used in irrigation system should be tested to determine its suitability to be used. To avoid salinity problems NaCl in irrigation water for prickly pear does not exceed 25 mol m-3. Furthermore, salinisation is increased by dryness that accelerate water evaporation from the soil, thus leading to a further concentration of the salts present, coming both from unsuitable irrigation water and from irrational fertilization practices.Different strategies can be put in practice to prevent soil salinisation: increasing soil organic matter content, mulching to reduce water evaporation and thus salt upward movement, using micro irrigation systems and microbial-based solutions.Prickly pear can be affected by several pathogens and pest insects which can compromise not only production but also the plant itself. In the Mediterranean area the main pests are represented by the cottony cochineal (Dactylopius opuntiae) and the fruit fly (Ceratitis capitata). However, also snails and slug can also contribute to limiting plant production. Concerning pathogens, these are primarily fungi like those belonging the genus Phytophtora. The expansion of its cultivation, the high planting densities as well as the climate changes may increase diseases incidences and even promote the emergence of new diseases and pests. Early detection, precise identification, and strict monitoring of the diseases are essential to prevent their diffusion.
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Video Lesson
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