Alley Cropping Research Articles

Integrating Livestock with Crops and Forestry for Sustainability

Global per capita consumption of animal protein is set to rise, particularly in developing economies, leading to a dramatic increase in meat consumption from 133 million tons in 1980 to 452 million tons by 2050. Notably, 86% of this increase, or 279 million tons, is expected to occur in developing countries. The expansion of animal-based agricultural systems, which cover 45% of the Earth's land area, presents significant challenges. These systems contribute substantially to agricultural emissions, including greenhouse gases such as nitrous oxide (N2O) and methane (CH4), and account for 8% of global water usage. The livestock sector is largely comprised of resource-constrained smallholders in developing nations. Environmental impacts arise from the lack of integration with other agricultural and forestry practices, disrupting the natural cycles of carbon, water, nitrogen, phosphorus, and sulfur. This disruption leads to increased emissions of N2O and CH4, water contamination, land degradation, and biodiversity loss. To address these challenges and support the United Nations' Sustainable Development Goals (SDGs) related to poverty reduction (SDG #1), hunger alleviation (SDG #2), clean water and sanitation (SDG #6), and climate action (SDG #13), it is essential to integrate livestock with crop and tree farming. Strategies to improve sustainability include incorporating pastures into crop rotations, using controlled grazing techniques, practicing agro-forestry such as alley cropping, and implementing systems like ley farming. Additional measures include precision feeding and protein matching to reduce enteric fermentation, repurposing emissions of CH4 and N2O, and effective manure management. Addressing greenhouse gas emissions through diverse approaches, reducing product wastage, minimizing antibiotic use, and restoring rangelands to enhance soil carbon storage are also critical for achieving sustainable livestock practices.

Changes in Clitoria ternatea Canopy Cover and its Relation to Forage Productivity under Leucaena leucocephala Alley Cropping and NPK Fertilization in Arid Agroforestry Systems of Saudi Arabia

Background: There is an increased need for intercropping practice in drylands to increase land-use efficiency. Canopy cover is a great tool to assess agricultural yield, as it is an indicator of plant health and productivity. Methods: The smartphone-based application Canopeo was used to measure the canopy cover (CC) of Clitoria under mixed intercropping with Leucaena and with four (4) fertilization levels (Control, 200 kg, 300 kg and 400 kg of NPK). Forage yield and (CC) were measured during six (6) consecutive harvests. Moreover, forage quality (NPK and protein) was analyzed. Result: The results revealed a high positive correlation between (CC) with crop yield and quality. Also, the application of fertilizers produced higher (CC) associated with higher yield and forage quality. The relatively low correlation of (CC) with yield in intercropping may be due to the high competition of the Leucaena tree. However, the whole intercropping system was positive (with an LER of 2.4), indicating better land-use efficiency. The results concluded that intercropping in drylands would result in better land use. While the application of NPK fertilizers will increase crop (CC), which in turn will reflect in higher forage yield and quality.

Poplar based agroforestry system: Symmetry to maximize productivity and optimized nutrient acquisition in fodder sorghum–wheat rotation in semiarid region of Haryana

A field experiment was conducted during the kharif and rabi season of 2 years (2022–24) at the farm of agroforestry of Chaudhary Charan Singh Haryana Agricultural University, Hisar to evaluate the impact of different geometry of poplar on the yield and nutrient uptake of sorghum and wheat under poplar-based agroforestry sys- tems. The experiment was laid out in a randomized block design with 3 replications. The sorghum and wheat were sown as per the treatment comprising different spacing of poplar i.e. 3 m × 3 m, 4 m × 3 m, 5 m × 3 m, 6 m × 3 m, 7 m × 3 m, 8 m × 3 m and control (sole crops without trees). The results showed that sorghum (14.02 and 14.48 t/ ha) dry fodder yield and wheat grain yield (5.14 and 5.30 t/ha) and straw yield (7.17 and 7.28 t/ha) were maximum under control in 2022–23 and 2023–24, respectively. The yield of sorghum (13.62 and 15.54%), wheat grain (44.55 and 45.66%) and wheat straw (39.05 and 39.15%) were lower at 3 m × 3 m spacing compared to control in 2022–23 and 2023–24, respectively. The increase in spacing of poplar increase the yield of sorghum and wheat during both the years of study i.e. least yields at 3 m × 3 m popular spacing and highest under 8 m × 3 m spacing. However, popular based system yields of sorghum (8.01 and 8.42%), wheat grain (50.18 and 50.00%) and wheat straw (42.56 and 42.44%) were higher under 8 m × 3 m than 3 m × 3 m spacing in 2022–23 and 2023–24, respec- tively. Similar significant results were obtained in case of nutrient uptake N, P and K as yield of sorghum (143.9, 147.2, 18.3, 19.9 and 31.4, 29.2 kg/ha) and wheat in grain (81.8, 83.4, 13.7, 14.3 and 13.3 14.4 kg/ha) and straw (26.8, 28.4, 7.5, 8.7 and 64.2, 66.3 kg/ha) under 8 m × 3 m during 2022–23 and 2023–24, respectively. Hence, control has significant effect on the yield and nutrient uptake of crops than under agroforestry systems. While, among all the treatments of poplar-based alley crop systems, spacing of 8 × 3 m the significantly higher green for- age, and grain yields and nutrient uptake.

Soil Carbon Dioxide Emissions and Carbon Sequestration with Implementation of Alley Cropping in a Mediterranean Citrus Orchard.

Agroecological ecosystems produce significant carbon dioxide fluxes; however, the equilibrium of their carbon sequestration, as well as emission rates, faces considerable uncertainties. Therefore, sustainable cropping practices represent a unique opportunity for carbon sequestration, compensating greenhouse gas emissions. In this research, we evaluated the short-term effect of different management practices in alleys (tillage, no tillage, alley cropping with Rosmarinus officinalis and Thymus hyemalis on soil properties, carbon sequestration, and CO2 emissions in a grapefruit orchard under semiarid climate). For two years every four months, soil sampling campaigns were performed, soil CO2 emissions were measured, and rhizosphere soils were sampled at the end of the experimental period. The results show that alley cropping with Thymus and Rosmarinus contributed to improve soil fertility, increasing soil organic carbon (SOC), total nitrogen, cation exchange capacity, and nutrients. The CO2 emission rates followed the soil temperature/moisture pattern. Tillage did not contribute to higher overall CO2 emissions, and there were no decreased SOC contents. In contrast, alley crops increased CO2 emission rates, especially Rosmarinus; however, the bigger root system and biomass of Rosmarinus contributed to soil carbon sequestration at a greater rate than Thymus. Therefore, Rosmarinus is positioned as a better option than Thymus to be used as an alley crop, although long-term monitoring is required to evaluate if the reported short-term benefits are maintained over time.

Role of Calliandra Calothyrsus Alley Cropping for Soil Fertility and Maize Production at Bako, Western Oromia

Role of Calliandra Calothyrsus Alley Cropping for Soil Fertility and Maize Production at Bako, Western Oromia

Tree effects on litter mass loss at different soil depths in a young temperate alley cropping system revealed with tea bag method

Tree effects on litter mass loss at different soil depths in a young temperate alley cropping system revealed with tea bag method

Tackling climate change: Agroforestry adoption in the face of regional weather extremes

The cultivation of agroforestry systems is regarded as an effective strategy that can help synergistically mitigate and adapt to the adverse impacts of climate change and regional extreme weather events. This study addresses the question of whether, and under what conditions, farmers are likely to adopt agroforestry systems in response to regional weather extremes and presents a novel research approach to tackle this question. A discrete choice experiment was conducted to elicit farmers’ preferences for agroforestry and wood-based land use systems. The results were combined with geospatial weather information. Assuming adaptive weather expectations, land users’ dynamic responses to extreme weather were simulated in terms of adoption probabilities. Farmers in the case study region in southeastern Germany were found to have a negative preference for alley cropping systems (i.e. agroforestry) and short rotation coppice, compared to an exclusively crop-based land use system. However, the results from the simulation of a 2018-like extreme weather event showed that alley cropping has a high probability of being adopted in the long-term. This study provides novel insights into the adaptive uptake of climate-resilient agroforestry systems. This information can be used to develop more effective policies and programs to promote agroforestry as a climate-resilient land-use strategy.

Comparing the economic performance of poplar-based alley cropping systems with arable farming in Brandenburg under varying site conditions and policy scenarios

Agroforestry can address multiple environmental challenges across the agricultural sector, for example biodiversity loss and soil degradation. However, agroforestry uptake remains low in Germany. Since economic considerations are important for farmer uptake, this paper compares the economic performance of conventional arable farming with silvoarable alley cropping in Brandenburg. Using a modelling approach, the net present value (NPV) is calculated to assess the competitiveness of alley cropping with poplar compared to arable farming under different scenarios. These scenarios cover a range of crops, rotation schedules, alley widths, woodchip prices, and yield levels. Additionally, policy measures that can compensate for potential economic losses associated with transitioning to agroforestry are considered. Results show that short rotation alley cropping had higher NPVs than medium rotation alley cropping, mainly due to cash-flow characteristics. Short rotation alley cropping can be competitive at high woodchip prices without policy support, while at low or average prices alley cropping needs subsidies to be competitive. Medium rotation systems at all price levels were not competitive unless policy support was provided. Current policy payments were unable to make silvoarable alley cropping competitive except at high woodchip prices. When subsidies increase, alley cropping can be competitive even at low or average woodchip prices and over a range of site conditions. Besides policy support, economic performance was strongly influenced by woodchip prices, relative yield potential of poplar and arable crops, and site conditions.

Agro-Ecological Practice for Sustaining Higher Productivity of Fennel Plant Using Alley Cropping System and Endophytic Fungi

Sustainable ecological agriculture is achieved by regulating the benefits of trees. The application of leguminous trees as alley cropping protects and increases soil fertility, improves the quality of water by intercepting pesticides, changes the local climate, improves biodiversity, and thus improves productivity. In order to evaluate the impact of alley cropping upon the growth and productivity attributes of fennel, an experiment was carried out during two seasons. The experiment included eight treatments. Fennel seeds were cultivated between Sesbania alleys and treated with N and endophytic fungi according to the eight treatments. After harvesting the fennel, different parameters were determined and biochemical analyses were conducted. All of the alley cropping treatments showed remarkable superiority in all measures of fennel growth and productivity compared to the sole crop treatment. Among the different alley cropping treatments, applying Sesbania at 4 m spacing with N fertilizer and EF increased most of the studied parameters in terms of the least number of days from planting until harvesting of fennel, herb dry weight, number of umbels, fruit yield, essential oil, N, P, and K content, and pigments. In contrast, the highest plant height was recorded with fennel–Sesbania at 2 m spacing + N fertilizer + EF. Applying fennel–Sesbania at 6 m spacing + N fertilizer + EF treatment resulted in higher stem diameter and increased the number of main branches compared to the other treatments.

The Influence of Trees on Crop Yields in Temperate Zone Alley Cropping Systems: A Review

Agroforestry is a multifunctional land use system that represents a promising approach to mitigate the environmental impact of agriculture while enhancing the resilience of agricultural systems and ensuring sustainable food production. However, the tree rows in agroforestry systems, particularly in alley cropping systems (ACS), can affect crop productivity on adjacent agricultural fields through various mechanisms. Hence, concerns about declining yields and reduced farm profitability persist and explain the reluctance of farmers to implement ACS on their land. In this review, we examine the available literature on the effects of temperate ACS on yields of various agricultural crops to evaluate if and to what extent crop yields in ACS are affected by tree presence. We identified that ACS crop yields often vary substantially across different species, geographical locations, weather conditions and ACS designs. Our analysis also revealed that several parameters are modified in ACS by the presence of tree rows affecting crop yields positively or negatively and that ACS design aspects play a crucial role in determining crop productivity.

SDEWES 2023: Barriers and Possibilities for the Development of Short-Rotation Coppice as an Agroforestry System for Adaptation to Climate Change in Central European Conditions

This article compares different production, economic, and selected environmental aspects of agroforestry systems in a standard (alley cropping) and a newly proposed design with fast-growing trees grown in short-rotation coppice. Our models of agroforestry systems (AFSs) are as follows: (i) alley cropping AFS with cherry and walnut trees in single rows (tree strips) with 28 m-wide arable fields between them (crop strips), and (ii) coppiced tree belt AFS with poplars and willows and 25 m-wide arable fields between them (crop strips). To evaluate the production characteristics of trees, we used yield curves from experimental plantations in conditions of the Czech Republic from previous research projects. Cost data were collected from long-term experimental plantations and combined with current operation and energy prices. The article presents an economic methodology for assessing the competitiveness of biomass production in AFSs under the current identified market conditions. Our results show that AFSs with short-rotation coppice can have similar economic and production results as annual crops if grown on suitable sites and with appropriate quality of agronomy. In comparison, alley cropping AFSs with fruit trees would not be economically viable for farmers without a significant subsidy for establishment and maintenance in the first years after establishment. Concerning the latest economic and political developments, the product from SRC (energy woodchips) can be evaluated as strategic, increasing the producer’s independence from purchased energy fuels.

Tree lines influence soil temperatures, sward growth dynamics and litter decomposition in permanent grassland

Climate change is likely to have a negative impact on soil functions in agro-ecosystems in the future. Alley cropping combines trees and agricultural crops or grassland on the same agricultural area. It has recently been discussed as more sustainable and resilient than comparable systems without trees for the temperate zone. So far, the influence of tree lines on biomass growth and decomposition of aboveground litter in the adjacent grassland is not fully clear. We measured the effect of tree lines on soil temperatures of an adjacent grass sward at five positions differing in distance and orientation (facing the tree line in the East or West) in a temperate alley-cropping system. Growth dynamics (sward height and soil cover) as well as litter half-life times for two cutting frequencies (four vs. two annual cuts) were monitored during two experimental years. The botanical composition at the transect positions was evaluated using the dry weight rank method. We found lower soil temperatures close to the trees, even though the proportion of soil cover was slightly lower close to the trees. The sward heights did not show a consistent pattern with respect to distance to the trees. Annual biomass accumulation was greatest at 6 m distance to the trees. An intermediate distance to the trees had a beneficial effect on productivity compared to the position with the lowest tree effect (25 m). Litter half-life times decreased with increasing sward height without a consistently positive/negative influence of the tree line over the examined growth periods. Lower litter half-life times in taller grass swards indicate that the sward height is the main factor driving litter decomposition while the influence of the trees is of minor importance.

Planting patterns in rubber agroforestry (Hevea brasiliensis) developed by the communities of Menggala Mas Village, Lampung Province, Indonesia

Abstract The agroforestry system provides important economic and ecological benefits for local communities, one of which is obtained from the application of planting patterns and plants species in it. This research aims to explain the planting pattern of rubber agroforestry developed by the community in Menggala Mas Village, Lampung Province, Indonesia. The approach in this research is qualitative. Data collection methods included observation, in-depth interviews, and documentation studies. The planting patterns of agroforestry system on their rubber plants were analysed. The research results showed that there are three agroforestry planting patterns implemented by the community, namely, alley cropping, trees along border and random mixture. The dominant combinations in alley cropping were rubber/karet (Hevea brasiliensis) – pulai (Alstonia scholaris) and rubber–mentru (Schima wallichii) – kayu afrika (Maesopsis eminii). The dominant combinations in trees along border were rubber–akasia (Acacia auriculiformis), rubber–jackfruit (Artocarpus heterophyllus) – cempedak (Artocarpus integer) and rubber–petai (Parkia speciosa) – jati (Tectona grandis). The dominant combinations in the random mixture were rubber–jengkol (Pithecellobium lobatum), rubber–petai–jengkol–akasia, rubber–jackfruit–cempedak, rubber–pulai–mengkudu (Morinda citrifolia L.) – jengkol and rubber–banana (Musa paradisiaca) – gadung (Dioscorea hispida) – sungkai (Peronema canescens Jack). Forty-one plant species were found. The local community wants to develop this planting pattern because the rubber agroforestry planting pattern can provide direct and indirect benefits such as a greater variety of plants which can increase their income; also, the products can be sold or consumed by the family, as a fence, fire break or barrier to other farmers’ land, can provide shade to reduce hot temperatures when farmers are working, and can reduce the risk of flooding and soil erosion to support soil and water conservation within the ‘Omou’ (garden/forest). The government and agricultural extension workers need to carry out regular guidance and outreach programmes regarding rubber agroforestry development strategies to increase public knowledge.

Processing rubber latex (Hevea brasiliensis) in agroforestry in Menggala Mas Village, Tulang Bawang Tengah District, Tulang Bawang Barat Regency

Local knowledge of rubber latex processing is important for village communities that depend on rubber plants for their livelihood. This research aims to determine the processing of rubber latex in agroforestry carried out by the community in Menggala Mas Village, Lampung Province, Indonesia. This research approach is qualitative. Data was obtained by observation, in-depth interviews, and documentation studies. Then, the data was processed by making data transcripts, coding, categorizing, drawing temporary conclusions, triangulating, and drawing conclusions so that the results obtained could be analyzed to determine the data processing. Local communities carry out rubber in agroforestry. The research results showed that three applications of agroforestry planting patterns were found, namely alley cropping (alley pattern), Trees along border (fence pattern), and random mixture (random pattern). The dominant combination in alley cropping is rubber-pulai, and rubber-mentru-afrika wood. The dominant combinations in Trees along the border are rubber-acacia, rubber-jackfruit-cempedak, rubber-petai-teak. The dominant combinations in the random mixture are rubber-jengkol, rubber-petai-jengkol-acacia, rubber-jackfruit-cempedak, rubber-pulai-noni-jengkol, rubber-banana-gadung-sungkai. The rubber latex processing process in agroforestry is carried out traditionally, starting from the tapping process, sap acidification, sap harvesting (napeu), sap separation, and sales and harvesting of agroforestry crops. The community's local knowledge has been passed down from their parents to reduce the costs of processing rubber latex from expensive materials so that the community can gain more profits. This has been proven if local communities can manage their land well, which can become a long-term source of livelihood. The government needs to assist with strategies for processing rubber latex as well as managing rubber agroforestry land to increase farmers' knowledge and harvest yields

The Effect of Fertilizer Rate and Pruning Material on Growth and Yield of Carrot (Daucus carota) under Alley Cropping System

The study was conducted at the Agroforestry Farm of Sylhet Agricultural University from October 2020 to March 2021 to evaluate the growth and yield performance of carrot and determine soil fertility status during the hedge establishment period of alley cropping. Hedges for alley cropping were established using ipil-ipil (Leucaena leucocephala) and vegetable hummingbirds (Sesbania grandiflora) tree species. The experiment was laid out in a randomized complete block design (RCBD). During the hedge establishment period, the carrot was cultivated in the alley of the hedgerow using four different treatments with three replications. The treatments were T0 (No application of fertilizer and pruning materials), T1 (application of recommended fertilizer dose), T2 (application of half dose of the recommended fertilizer + pruning materials), and T3 (application of pruning materials). The results exhibited that growth parameters, viz. plant height (cm), leaf number per plant, root length (cm), and root diameter (cm) of carrot were almost similar in all treated plots, except control (T0). The carrot yield was statistically similar in all fertilizer and pruning materials treated plots, but it was drastically reduced in the control plots and decreased by about 40-45% compared to fertilizer and pruning materials applied plots. During hedgerow establishment, soil pH among different plots has not changed significantly compared to the initial field, but organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) in different alleys found to be increased significantly in treatment T2 and treatment T1 after carrot cultivation. Improvement in soil fertility was also found in the alleys between the hedgerows of ipil-ipil and vegetable hummingbirds when only pruning material was applied to the soil. Therefore, an alley cropping system with Leucaena leucocephala and Sesbania grandiflora may enhance the yield performance of carrot and organically improve soil fertility during the hedge establishment period.

Agroforestry and Its Potential for Sustainable Land Management and Climate Action: A Review

Agroforestry, the integration of trees and shrubs with crops and/or livestock, stands as a pivotal strategy in sustainable land management and climate action. This review synthesizes current knowledge and practices of agroforestry, focusing on its diverse systems, contributions to sustainable land management, role in climate change mitigation and adaptation, and the challenges and future prospects, with a special emphasis on the Indian context. Agroforestry systems, classified into silvopastoral, agrosilvicultural, and silvoarable, along with specialized practices like alley cropping and forest farming, demonstrate significant adaptability across various climatic and geographical regions. These systems have shown promising results globally, evident in case studies highlighting their effectiveness in different environmental settings. In the realm of sustainable land management, agroforestry is instrumental in soil conservation, enhancing soil fertility, and nutrient cycling. It also plays a critical role in biodiversity conservation and the enhancement of ecosystem services, such as water regulation and pollination. Socioeconomically, agroforestry contributes to improving livelihoods and economic resilience, as demonstrated in various local community case studies. In addressing climate change, agroforestry systems are notable for their carbon sequestration capabilities. Compared to traditional agricultural practices, these systems exhibit a higher potential for carbon storage, both above and below ground. They also enhance resilience to climate extremes, offering adaptive strategies for farmers and communities facing climatic variability. Policy and global initiatives increasingly recognize agroforestry's role in climate action, with international agreements and organizations fostering its integration into national policies. The implementation of agroforestry is not without challenges. Technical complexities, the need for site-specific knowledge, economic and policy barriers, and sociocultural factors pose significant hurdles. For India, a country with diverse agro-ecological zones, these challenges are coupled with opportunities for research, technological innovation, policy improvement, and global-local collaborations. The future prospects for agroforestry are vast, particularly in the Indian context, where it can significantly contribute to sustainable agriculture and rural development. Continued research, policy support, and collaborative efforts are essential to fully realize the potential of agroforestry in environmental conservation, climate change mitigation, and socioeconomic development.

Comparative analysis of effects of climate-smart agriculture practices and conventional agriculture on selected soil physicochemical properties in Nyimba district, Zambia

Background. Many smallholder farmers in the developing world live in adverse poverty and rely on agriculture as their primary source of income and household food. In Zambia, agriculture production is the main activity for people in rural areas of the country. The study evaluated the effects of climate-smart practices: Gliricidia sepium alley cropping, conservation agriculture basin, ripping, and conventional agriculture cropland on selected physicochemical properties of soil among smallholder farmers’ croplands in Nyimba district, Zambia. Materials and Methods. Cropland under conservation agriculture basin, ripping, agroforestry gliricidia alleyed cropping, and conventional agriculture cropland hosting the practices for more than five years were considered for soil sample collection. Thirty (30) composite soil samples were collected: gliricidia alley cropping (n = 6), conservation agriculture ripping (n = 6), basin (n = 6), conventional agriculture one (n = 6), and conventional agriculture two (n = 6) following a zigzag pattern on soil surface depth of 0–30 cm. The collected composite soil samples were analyzed at the University of Zambia Soil Science Laboratory. Soil laboratory results were analyzed with Minitab Statistical Software version 17 for mean squares, standard deviations, and Tukey’s LSD. Results and Discussion. The study revealed significant effects (p <0.05) of gliricidia alley cropping, conservation agriculture ripping, and basin on soil bulk density, porosity, power of hydrogen (pH), cation exchange capacity, available phosphorus, total nitrogen, exchangeable bases sodium, calcium, and potassium. Exchangeable base magnesium was recorded as insignificant across the considered practices off-course with minimal mean variations with conventional agriculture cropland. Conclusion. The study shows that implementing climate-smart agriculture practices has the potential to improve crop productivity per hectare through reclaiming and amending depleted soil physicochemical properties in a mid and long run. This also indicates the importance of climate-smart agricultural practices implementation among smallholder farmers’ cropping fields.

Tracking earthworm fluxes at the interface between tree rows and crop habitats in a Mediterranean alley cropping field

Alley cropping is the combination of tree rows and crop alleys. The tree row is covered by an understory vegetation strip (UVS), providing a beneficial habitat for many soil fauna, which could disperse through spillover to the crop alleys. However, such movements have never been directly studied. Our experiment investigated earthworm fluxes in the tree row vicinity using a trap technique, in a Mediterranean agroforestry alley cropping field cultivated with peas and planted with walnut trees. We assessed earthworm density at different distances from the UVS (0 m, 0.3 m, 1 m and 6 m) by hand sorting soil monoliths (25*25*30 cm) in spring 2019, at the start and the end of a two-month experiment. During this period, we detected earthworm fluxes by placing directional traps at 30 cm from the UVS border. Traps consisted of three glued plastic walls placed vertically in the soil. They delimited a soil block of 25*25 cm by 20 cm depth and were open on one side. More epigeic earthworms were found in the UVS and up to 30 cm from the UVS border than in the middle of the crop alley. By contrast, the earthworm Allolobophora chlorotica presented a homogeneous distribution in the plot. Trapped earthworms were mostly of the All. chlorotica species, and 1.6 times more earthworms were found in traps open towards the crop alley than in traps open towards the UVS. These results suggest that in spring, earthworms are moving more from the crop alley towards the UVS than in the other direction, probably using the tree row and its vicinity as a refuge against adverse summer conditions in the crop alley.

Diversified cropping systems effect on the water status of mandarin trees under deficit irrigation

The diversified cropping systems has several environmental benefits, but there is no certainty about their effect on the water status of trees, especially in areas with permanent low availability of irrigation water. Therefore, our objective was to evaluate the effect of the establishment of diversified cropping systems in a traditional monoculture (MC) of adult mandarin trees on its water status and yield under sustained deficit irrigation (SDI) and regulated deficit irrigation (RDI). Six treatments were tested during three consecutive seasons: (i) a mandarin monoculture under SDI (MC-SDI), with permanent bare alleys and irrigated at ∼70 % ETc during the entire season (actual amount of irrigation water available in the area); (ii) a diversified mandarin crop (D1-SDI), irrigated as MC-SDI, with a rotation of fava bean and barley/vetch in the alleys; and (iii) a second diversified mandarin crop (D2-SDI), irrigated as MC-SDI, with a seasonal rotation of fava bean, purslane and cowpea. Additionally, three RDI treatments were evaluated, denoted as (iv) MC-RDI, (v) D1-RDI and (vi) D2-RDI, irrigated as MC-SDI, except during the stage II of fruit growth, when it was reduced by 50 % with an irrigation threshold of a solar midday stem water potential of ∼ –1.5 MPa. The mandarin yield was not affected by the effect of diversified cropping systems, but the RDI reduced it on average by 30.1 % with respect to SDI. The alley cropping of fava bean and barley/vetch during winter and spring under sustained deficit irrigation conditions reduced the water stress intensity of mandarin trees by 26.9 % over the entire season, while cultivation of purslane or cowpea during summer increased it by 60–144 %. Both diversifications required a greater amount of water than the monoculture, in these terms an additional reduction in the irrigation of mandarin trees, as in the RDI treatment, allowed to solve this additional water requirement, but promoted an increase in the water stress intensity of the trees, which may affect their productivity in the mid and long-term.

Intercropping in rainfed Mediterranean olive groves contributes to improving soil quality and soil organic carbon storage

Given the current degradation problems that Mediterranean soils endure, the implementation of alley cropping in olive orchards has been suggested as a sustainable strategy to increase agricultural productivity and improve carbon storage and soil fertility. Therefore, the objective of this study was to evaluate in the short term (3 years) the effect of alley cropping with minimum tillage versus conventional tillage in a traditional rainfed olive grove on soil organic carbon, total nitrogen concentrations, and stocks. Changes in soil quality through a stratification index, and the success of the 4‰ strategy in these soils with this type of management were also evaluated. Three intercropping strategies were tested: Crocus sativus (D-S), Vicia sativa and Avena sativa in rotation (D-O), and Lavandula x intermedia (D-L), all with minimum tillage versus olive with conventional tillage without intercropping, which was used as a control. Intercropping increased soil organic carbon in topsoil (0–10 cm) by 41.1, 28.5, and 30.5% for D-S, D-O, and D-L, respectively, compared to conventional tillage. At a depth of 10–30 cm, the soil organic carbon and the soil organic carbon stock increased slightly, although significant differences were found only in D-L. In the diversified plots, total nitrogen did not vary. However, total nitrogen increased in olive with conventional tillage due to fertilisation. Concerning soil quality, no significant differences were observed when evaluating the soil carbon and nitrogen stratification index in any of the treatments. However, the implementation of intercropping reached the objectives set by the 4‰ initiative in these soils with an increase in soil carbon per hectare and per year of 80, 87.4, and 86.4% for D-S, D-O, and D-L, respectively. Therefore, based on these results, in the short term, intercropping treatment enhances carbon storage in these soils, effectively achieving the objectives of the 4‰ initiative.