Trees In Agroforestry Systems Research Articles

The potential of agroforestry to buffer climate change impacts on suitability of coffee and banana in Uganda

Coffee, an important global commodity, is threatened by climate change. Agroforestry has been considered as one option to maintain or enhance coffee production. In this study, we use a machine learning ensemble consisting of MaxEnt, Random Forest and Boosted Regression Trees to assess climate change impacts on the suitability to grow Arabica coffee, Robusta coffee and bananas in Uganda by 2050. Based on this, the buffering potential of Cordia africana and Ficus natalensis, the two commonly used shading trees in agroforestry systems is assessed. Our robust models (AUC of 0.7–0.9) indicate temperature-related variables as relevant for Arabica coffee suitability, while precipitation-related variables determine Robusta coffee and banana suitability. Under current climatic conditions, only a quarter of the total land area is suitable for growing Arabica coffee, while over three-quarters are suitable for Robusta coffee and bananas. Our results suggest that climate change will reduce the area suitable to grow Arabica coffee, Robusta coffee and bananas by 20%, 9% and 3.5%, respectively, under SSP3-RCP7.0 by 2050. A shift in areas suitable for Arabica coffee to highlands might occur, leading to potential encroachment on protected areas. In our model, implementing agroforestry with up to 50% shading could partially offset suitable area losses for Robusta coffee—but not for Arabica coffee. The potential to produce valuable Arabica coffee thus decreases under climate change and cannot be averted by agroforestry. We conclude that the implementation and design of agroforestry must be based on species, elevation, and regional climate projections to avoid maladaptation.

Performance of a winter wheat composite cross population in two temperate agroforestry systems – a Swiss case study

In agroforestry systems (AFS), where environmental conditions are highly variable at small spatial scales, the use of uniform genetic material of a single cultivar commonly grown in monoculture cropping might not be optimal. However, the use of composite cross populations (CCPs) that contain an inherent genetic variability might be a promising approach under the environmental variability created by trees in AFS. In this experimental trial, the performance of a CCP (‘CC-2 k’) of winter wheat was compared to a commercial variety (‘Wiwa’) in a split-plot design at two AFS (Feusisberg and Wollerau) in Central Switzerland. Yield of CC-2k (1.9 ± 0.7 Mg ha−1) was higher than yield of Wiwa (0.7 ± 0.4 Mg ha−1) in Wollerau, but yields did not differ between CCP and variety in Feusisberg (1.9 ± 0.7 Mg ha−1 and 2.0 ± 0.8 Mg ha−1, respectively). The interaction of site and variety was significant (p < 0.05). Wiwa had a higher protein, Fe and Ca content than CC-2k. Therefore, while the CC-2k outperformed Wiwa in terms of yield in one of the two AFS, Wiwa outperformed CC-2k in terms of quality. In this one-year field experiment, the composite cross population might have been better adapted to the heterogenous environment of agroforestry systems (found in one out of two sites) but failed to reach the high-quality product of modern cultivars. These initial results must be seen as first insights which need to be complemented by larger field experiments for generalisation. The findings of this study may be interpreted as an indication that further improvements in terms of quality might make CCPs a viable option for diversified agricultural systems with larger environmental heterogeneity than common monoculture cropping systems.

Shade tree trait diversity and functions in agroforestry systems: A review of which traits matter

Abstract Shade trees in agroforestry systems confer ecosystem services, such as enhanced soil fertility from diverse litter inputs, microclimate regulation via shade, and disease mitigation through trophic and abiotic interactions. With this thriving role of agroforestry in sustainable agriculture, particularly for tree crops, systematic and reliable methods to select shade trees for specific agroecosystem outcomes are crucial. Plant functional traits offer a framework to describe, select and manage shade trees. Over the last decade, shade tree leaf functional traits and whole plant traits have been assessed in agroforestry systems. Yet, we lack amalgamated information on (i) what we know about shade tree trait relationships with functions to achieve desired agroecosystem outcomes, (ii) how decades of shade tree selection by farmers impacts agroforests inter‐ and intraspecific trait diversity, and (iii) which shade tree traits should be considered for achieving farmer priorities. We consolidate literature on Coffea arabica (coffee) and Theobroma cacao (cocoa) agroforestry systems to summarize the role of shade tree functional traits in three key ecosystem functions: soil fertility, microclimate modification and crop productivity. We compile global and regional datasets on tree functional trait diversity to show the functional space of agroforestry tree species compared with the overall functional space observed in plants. Despite, or maybe because of, high shade tree diversity, shade tree trait characterization remains coarse and commonly measured at the community scale in the literature. Based on published trait data, we show that farmers adjust the functional composition of shade trees to increase the recycling of soil nutrients (high leaf nitrogen), the production of wood (skewing towards lower wood densities) and the production of fruits (tendency towards high seed size). Common shade trees in coffee and cocoa systems fall in the mid‐range of leaf acquisitive to conservative strategies, providing evidence that expanding shade tree portfolios can improve, or even accelerate, functions. Synthesis and applications: Based on the agroforestry literature and on trait‐environment relationships, we propose a matrix of shade tree traits that influence desirable agroecosystem outcomes for farmers, which can guide fine‐scale coordination of trait expression and agroforestry functions.

Proximity to natural forests failed to rescue a declining agroforestry tree species

The conservation of species in human-modified landscapes such as agroforestry systems is central to global conservation and sustainable use of biodiversity. Understanding the dynamics of key species in agroforestry systems is important for predicting the sustainability of these systems. However, the population dynamics of agroforestry tree species are often unknown, and planning for the management of these systems is generally grounded on the untested assumption that the tree component will persist over time. Here, we developed an integral projection model for Vitellaria paradoxa (Sapotaceae), one of the most important tree species in traditional agroforestry systems in West Africa. We collected three years of demographic data from six populations around the Pendjari Biosphere Reserve in Benin to parameterize this model and test the effect of populations’ proximity to natural habitats on the short- and long-term dynamics of V. paradoxa. However, models suggest that V. paradoxa populations are projected to decline at a yearly rate of 10.6% and within the next two decades, this tree will be locally extinct. We found a significant positive effect of proximity to natural forest on the long-term population dynamics, but this failed to save populations from decline. Elasticity analyses show that the best strategy to slow down such a decline includes preserving the largest mature trees. However, traditional management systems that protect shea butter trees in agroforestry systems are now replaced by increasing tree cutting to produce firewood, charcoal and carve out mortars and pestles. The decline of this key agroforestry tree poses a broader threat to long-term sustainability of agroforestry systems.

The Argentinian experience with yerba mate in agroforestry

Agroforestry is able to address two of society’s great contemporary issues, climate change mitigation and food security. Characterised by the presence of trees within croplands and farmland, agroforestry has been recognised for its ability to enhance biomass and soil carbon while sustaining agricultural production. Agroforestry’s many environmental and ecosystem services - including water quality improvement, erosion control, and biodiversity enhancement - may also help achieve a number of other United Nations Sustainable Development Goals, including renewable energy, responsible consumption and life on land. Yerba mate (YM) is a tree species that is native to South America, which has traditionally been harvested for its leaves, which are used to prepare a traditional infusion. Over the years, new YM products have emerged, including dehydrated powder for instant preparation. The cultivation of YM has evolved from traditional forest stands to large-scale monoculture plantations, but there is recent interest in sustainable agroforestry approaches. Research in Argentina's Misiones Province has demonstrated the benefits of YM being shaded by other trees in agroforestry systems, including increased yields of YM and an enhancement of preferred flavours of the leaves, as well as increased soil fertility, carbon sequestration and protection against extreme weather conditions. To continue to improve upon YM agroforestry, the I 049 Agroforestry project plans to study YM cultivation in agroforestry arrangements to better support sustainable agroforestry practices and innovative marketing strategies in Argentina.

Diameter growth of eucalyptus trees in agroforestry systems and its relation to air temperature and precipitation

Diameter growth of eucalyptus trees in agroforestry systems and its relation to air temperature and precipitation

The impact of native trees, Cordia africana and Ficus sur, and the economically valuable Manihot esculenta on soil chemical properties in an agroforestry system

Native trees in agroforestry systems sustain soil properties by building up and recycling nutrients in a sustainable manner. This manuscript aimed to assess the impact of different agroforestry species on soil chemical properties. Soil samples were collected from within and outside the canopy zones of native tree species (Cordia africana, Ficus sur) and a perennial tuber crop (Manihot esculenta) in agroforestry systems at three different elevations. The results showed that, the soil chemical properties were significantly better within the canopy zones of all agroforestry species compared to outside. However, there was insignificant difference in pH between the soil inside and outside the canopy of Manihot esculenta. With a few exceptions, the evaluated soil chemical parameters exhibited minimal variations between Cordia africana and Ficus sur. Interestingly, Manihot esculenta had the least positive impact on soil chemical properties in the agroforestry system, indicating that native tree species enhance soil chemical properties more effectively than the tuber crop. The influence of agroforestry species on soil chemical properties remained consistent across all elevation ranges, suggesting that elevation does not alter the effects of agroforestry species on soil properties. In general, native trees, Cordia africana, and Ficus sur, positively contribute to soil chemical properties, while Manihot esculenta has a negative impact, particularly on cation exchange capacity, soil pH, and available potassium in comparison to the native tree species. These findings highlight the importance of using native tree species in agroforestry systems to promote healthy soil chemical properties and enhance the resilience of forest ecosystems.

Allometric relationships between stem diameter, height and crown area of associated trees of cocoa agroforests of Ghana

Allometric models which are used to describe the structure of trees in agroforestry systems are usually extrapolated from models developed for trees in forest ecosystems. This makes quantitative assessment of the functions of shade trees in agroforestry systems challenging since increased availability of light and space in these systems may induce structural differences from those growing under forest conditions. We addressed this issue by providing species-specific allometric information on the structural characteristics of associated shade trees on cocoa agroforestry systems and assessed if allometries conformed to theoretical predictions. At the plot level, stand and soil characteristics affecting tree structural characteristics were assessed. The study was conducted in cocoa agroforestry systems at Suhum, Ghana. The height-diameter at breast height (H-DBH) allometry had the best fits (R2 = 53–89%), followed by the crown area (CA)-DBH allometry (R2 = 27–87%) and then the CA-H allometry (R2 = 22–73%). In general, the scaling exponents of the CA-DBH, H-CA and H-DBH allometries conformed to the metabolic scaling theory (MST). However, both the CA-DBH and H-DBH allometries diverged from the geometric similarity model. Though forest tree species had similar crown areas as fruit trees, they were slenderer than fruit trees. Tree slenderness coefficients were positively correlated with soil P, Ca, Cu and the ratios (Ca + Mg):K, (Ca + Mg):(K + Na) and Ca:Mg, but not C:N while DBH and H were correlated with soil P and C:N ratio. Our results show that critical soil nutrients and their ratios affects shade tree structural attributes (e.g. slenderness and CA), which possibly restrict variations in species-specific allometries to a narrow range on cocoa systems. Furthermore, shade tree species richness and density are better predictors of relative canopy projection area (a proxy for shade intensity) than tree species diversity. In conclusion, the results have implications for shade tree species selection, monitoring of woody biomass and maintenance of biodiversity.

Growth and carbon sequestration in biomass of Cordia alliodora in Andean agroforestry systems with coffee

Timber production and carbon sequestration in trees in agroforestry systems (AFS) are key to productivity and climate change mitigation. There are no studies about dynamics of growth and carbon sequestration of Cordia alliodora during all plantation cycle. The objective of this study was to develop models for diametric growth and carbon sequestration in aboveground biomass of C. alliodora in AFS with coffee in Líbano, Tolima, Colombia. Nonlinear models of growth and carbon sequestration in aboveground biomass of C. alliodora in AFS with coffee were developed. A total of 90 trees, ranging in age from 1 to 19 years, were randomly selected in farms and measured (diameter at breast height -dbh- and total height -h) in AFS with a basal area of C. alliodora between 0.22 and 17.8 m2/ha. Timber volume and aboveground biomass were estimated with allometric models, while carbon was estimated by multiplying aboveground biomass by 0.47. The best-fit models were selected according to the coefficient of determination (R2), Akaike's information criterion (AIC), predicted residual error sum of squares (PRESS), biological logic and a residual analysis. The highest growth rate of this species was reached at 4–6 years for dbh and h (3.6 cm/year and 2.9 m/year, respectively) and at 20 years for timber and carbon (0.60 m3/tree/year and 88.9 kg C/tree/year, respectively). In 20 years, a C. alliodora tree would store 1.1 Mg C and a AFS with 60 trees/ha would sequester between 260 Mg CO2/ha in aboveground biomass. The results show that C. alliodora trees could be maintained in the field for more than 20 years, thus increasing the volume per individual and carbon sequestration for a longer time. This demonstrates the importance of this species mainly when timber production and carbon sequestration are priorities for its profitability.

Tree Effects on Coffee Leaf Rust at Field and Landscape Scales.

Although integrating trees into agricultural systems (i.e., agroforestry systems) provides many valuable ecosystem services, the trees can also interact with plant diseases. We demonstrate that a detailed understanding of how plant diseases interact with trees in agroforestry systems is necessary to identify key tree canopy characteristics, leaf traits, spatial arrangements, and management options that can help control plant diseases at different spatial scales. We focus our analysis on how trees affect coffee leaf rust, a major disease affecting one of the world's most significant crop commodities. We show that trees can both promote and discourage the development of coffee leaf rust at the plot scale via microclimate modifications in the understory. Based on our understanding of the role of tree characteristics in shaping the microclimate, we identify several canopy characteristics and leaf traits that can help manage coffee leaf rust at the plot scale: namely, thin canopies with high openness, short base height, horizontal branching, and small, dentate leaves. In contrast, at the edge of coffee farms, having large trees with high canopy volume and small, thick, waxy leaves is more useful to reduce throughflow wind speeds and intercept the airborne dispersal of urediniospores, an important consideration to control disease at the landscape scale. Seasonal pruning can help shape trees into the desired form, and trees can be spatially arranged to optimize desired effects. This case study demonstrates the added value of combining process-based epidemiology studies with functional trait ecology to improve disease management in agroforestry systems.

Establishment and Natural Regeneration of Native Trees in Agroforestry Systems in the Paraguayan Atlantic Forest

The establishment of planted trees and the natural regeneration of trees in agroecosystems is challenging. This study evaluated the establishment and natural regeneration of the following six native tree species in two agricultural systems in the Atlantic Forest in Paraguay: Cedrela fissilis Vell., Cordia trichotoma (Vell) Arráb. ex Steud., Handroanthus albus (Cham.) Mattos, Handroanthus impetiginosus (Mart. ex DC.) Mattos, Peltophorum dubium (Sprengel) Taubert, and Cordia americana (L.) Gottschling and J.S.Mill. At the study site in Caaguazú, 18 plots of 100 m2 each were established in 2 agronomic systems (conventional or agroecological) featuring 3 plantation types (pathsides, agricultural field edges, and islets). Trees were planted at this site in spring 2010 at a density of 1800 individuals ha−1, and the site was monitored for six years. At the study site in Itapúa, 30 plots of 50 m2 each were established in three agronomic systems (conventional, traditional, or agroecological). Trees were planted at this site in spring 2012 at a density of 1600 individuals ha−1, and the site was monitored for four years. Survival and relative growth rates of the planted species and natural regeneration were analyzed using generalized linear mixed models that considered species, agronomic system, and plantation type as fixed factors, and time and plot as random factors. At both sites, survival varied among species. Here, C. fissilis showed lower survival and C. trichotoma higher growth than the other species. Naturally regenerated species were C. trichotoma, H. albus, and P. dubium. The agronomic system and species affected growth and natural regeneration at both locations. Plantation type affected survival and growth in Caaguazú only. We conclude that species contributes more than agronomic system or plantation type to determining the survival, relative growth rate, and natural regeneration in agroforestry systems in the Paraguayan Atlantic Forest.

Different factors drive the assembly of pine and Panax notoginseng-associated microbiomes in Panax notoginseng-pine agroforestry systems.

Land-use conversion affects the composition and assembly of plant-associated microbiomes, which in turn affects plant growth, development, and ecosystem functioning. However, agroforestry systems, as sustainable land types, have received little attention regarding the dynamics of different plant-associated microbes. In this study, we used high-throughput sequencing technology to analyze the assembly mechanisms and the driving factors of pine- and Panax notoginseng (P.n.)-associated microbiomes during the conversion of different pine forests (Pinus kesiya var. langbianensis and Pinus armandii) into P.n.-pine agroforestry systems. The results showed that the conversion of pure pine forest into P.n.-pine agroforestry systems significantly altered the diversity of pine-associated fungi rather than the community structure, and the community structure of P.n.-associated fungi rather than the diversity. Additionally, plant-associated fungi were more responsive to land-use change than bacteria. Main effect analysis revealed that compartment rather than genotype was the driving factor of pine- and P.n.-associated microbiomes, but P.n. cultivation also significantly affected the assembly of pine-associated microbiomes. In addition, there was a transfer of P.n. endophytes to pine trees in agroforestry systems and the beneficial microbiomes (Massilia, Marmoricola, Herbaspirillum, etc.) were enlarged in pine roots. Therefore, the diversity of the assembly mechanisms of P.n.- and pine-associated microbiomes played an important role in the P.n.--pine agroforestry systems and were the basis for the sustainable development of the P.n.--pine agroforestry systems.

Tree diversity and shade rate in complex cocoa-based agroforests affect citrus foot rot disease

The role of agroforest systems in pathogen regulation through structural characteristics such as shade and tree diversity is recognized. However, few studies have examined the importance of these factors on the spread of diseases of associated fruit trees in agroforestry systems, especially cocoa-based agroforestry systems (CBAS). The aim of this study was to evaluate the effect of associated tree diversity and shade rate into CBAS on citrus Phytophthora foot rot disease (PFRD) intensity. The study was carried out in five citrus production basins of Cameroon, contrasted by ecology and rainfall regimes. A set of 33 CBAS plots was mapped and their species composition and vertical structure were determined. Field data were used to reconstruct CBAS in 3D with Shademotion 5.1.47 software. Using static simulations with shadow overlays, shade rate received by each citrus tree was calculated. Subsequently, citrus trees were grouped into three categories according to the shade rate they received: (i) full sun, with shade rate <30%; (ii) light shade with shade rate 30–70% and, (iii) dense shade, with shade rate >70%. PFRD intensity was determined by measuring the canker extent relatively to the citrus crown circumference. A significant difference in PFRD intensity was observed between the different shade rates. Citrus trees receiving no shade were significantly more attacked by PFRD than those receiving little shade or dense shade. The antagonistic effect of shade was demonstrated. At the expense of factors related to the specific composition of the CBAS, shade, temperature, relative humidity and rainfall were found to be the main factors explaining PFRD intensity in CBAS. This study shows that microclimatic alterations due to the biodiversity in tropical agroforestry systems contribute to sustainable pest management.

Digging deeper: microbial communities in subsoil are strongly promoted by trees in temperate agroforestry systems

AimsTemperate alley-cropping agroforestry systems maintain agricultural production while offering several environmental benefits. Central benefits of agroforestry systems such as the ‘safety-net’-role of the trees for leached nutrients are mainly due to processes occurring below the soil surface: the subsoil. Microorganisms in the subsoil may play a key role in the ‘safety-net’-function as they can improve the capturing and uptake of nutrients by the trees. Systematic investigations of microbial communities in temperate agroforestry systems, however, are restricted to topsoil.MethodsWe quantified bacteria, fungi, and functional groups of microorganisms in the topsoil and subsoil of two alley-cropping systems using real-time PCR. Topsoil and subsoil samples were collected in the tree rows and at multiple distances from the trees within the crop rows of the agroforestry systems as well as at an adjacent monoculture cropland.ResultsMicrobial population size decreased with soil depth likely due to limited resource availability in subsoil. Tree rows in agroforestry systems not only promote soil microbial populations in both the topsoil and subsoil but the promotion also extends gradually into the crop rows of the systems. The promotion of microorganisms through trees is stronger in subsoil than topsoil, pointing at more intense resource scarcity in the subsoil than topsoil.ConclusionsWe propose that tree root-derived resources and root litter, which are scarce in agricultural subsoils, triggered the strong positive response of the subsoil community to the trees. Finally, we provide initial evidence that subsoil microorganisms contribute to the ‘safety-net’-role of the trees in agroforestry systems.

Effect of intercrops complexity on water uptake patterns in rubber plantations: Evidence from stable isotopes (C-H-O) analysis

Rubber monoculture plantations are expanding but may cause environmental problems, and rubber-based agroforestry can provide ways of more environmentally friendly rubber cultivation. The general objective of this study was to investigate plant soil water uptake in different rubber agroforestry systems with water stable isotopes (δ2H and δ18O), and water use efficiency with leaf δ13C. We studied rubber trees in a monocultural plantation, and in three agroforestry systems which were mixed with (a) orange trees, (b) tea trees, and (c) both orange and tea trees, respectively. The results indicated that soil water content was enhanced in the agroforestry systems, especially for rubber-tea and rubber-orange-tea agroforesty systems. The soil water uptake of rubber trees varied seasonally, and exhibited significant different among the cultivation systems. Rubber trees in agroforestry systems seemingly absorb water from deeper soil horizons more than monocultural plantations. We also found that rubber trees adjusted their water source according to their growing stage: they increased their uptake of water from deeper soil horizons to meet water requirements during their leaf flushing stage. For the soil water uptake of intercrops, we found that they use a shallow soil horizon as their primary source of water uptake, with little seasonal variation in vertical water extraction patterns. Changes in leaf δ13C values indicate that rubber trees adjusted their water use efficiency seasonally, which helps to cope with seasonal drought and growth requirements. However, neither intercrops nor rubber trees’ δ13C values differ with sites, indicating that intercropping has little influence on intercrops and rubber trees’ water supply. In conclusion, rubber trees have a flexible water use strategy, as intercropping shaped the soil water uptake patterns of rubber trees without apparent consequences on water use efficiency. These findings provide valuable insights into agroforestry systems’ interspecific water use patterns that can help intercrop selection for rubber agroforestry systems in this region.

Impact of Olive Trees on the Microclimatic and Edaphic Environment of the Understorey Durum Wheat in an Alley Orchard of the Mediterranean Area

In the current context of climate change, the impact of trees in agroforestry systems is expected to mitigate water and heat stresses, particularly in semi-arid environments. Within this framework, in a two-year trial conducted at INRAE in Southern France, the dynamics of microclimatic parameters and the edaphic environment of durum wheat were investigated under a yearly-pruned (AF) and a never-pruned (AF+) 6-m apart alley olive orchard, in comparison with controls under full sun. Here it was recorded a reduction of photosynthetic active radiation (PAR) by 30% and 51% in AF and AF+, respectively, during the wheat cycle, together with a marked reduction of wind speed compared to controls (–85% in AF and −99% in AF+). A significant buffer effect was also highlighted for air temperature, averagely +1.7 °C during the night and −3.2 °C during the daytime under the moderate shading of AF. The positive effect of trees on soil water conservation increased with the intensity of shading, particularly during the critical wheat stage of grain filling, with benefits on wheat root mycorrhization, and NH4+ and NO3− abundance in the arable layer. Despite some of the environmental modifications being favorable for the understorey wheat, these were not translated into yield improvements, suggesting that the severe shading associated with the small inter-row and evergreen trees has a prevailing effect, that requires to be managed through appropriate tree pruning.

Support trees in vanilla agroforests of Madagascar: diversity, composition and origin

Trees in agroforestry systems provide multiple ecological and economic functions. Smallholder vanilla agroforests include shade trees common across agroforestry systems, and small-statured support trees carrying the vanilla vine. Support trees have received little scientific attention so far. The objectives of our study were to assess the diversity, composition and geographic origin of support trees in vanilla agroforestry systems of north-eastern Madagascar. The region is a global biodiversity hotspot, has been undergoing a rapid land-use change and produces a large share of the globally traded vanilla spice. The studied vanilla agroforests differed in land-use history: established either directly inside forest (forest-derived) or on land previously used for slash-and-burn agriculture (fallow-derived). Among the support trees, we found 122 species of which 25% were endemic to Madagascar. The species richness per plot was four times higher in forest-derived than in fallow-derived vanilla agroforests. The species distribution was particularly uneven in fallow-derived vanilla agroforests with one species (Jatropha curcas) comprising 52% of all individuals. In forest-derived vanilla agroforests, 44% of all trees were native or endemic to Madagascar, whereas in fallow-derived vanilla agroforests only 11% were native or endemic. We conclude that there is a considerable diversity among support trees in Malagasy vanilla agroforestry. The support tree diversity is strongly affected by land-use history. Fallow-derived vanilla agroforests currently have a comparatively low species richness, yet they can play an important role in land rehabilitation, and more emphasis on growing native and endemic tree species would contribute to aligning production with conservation goals.

Growth and yields of two varieties of maize (Zea mays L.) intercropped with peanut (Arachys hypogaea L.) applied by bokashi plus fertilizer between the rows of teak trees based agroforestry system

Nutrient shortages are the main problems faced by farmers, so as to improve soil fertility using organic fertilizer is compulsory. The main objective was to analyze the effects of bokashi plus fertilizer on the growth and yields of two varieties of maize intercropped with peanut under three years old teak trees in agroforestry system. The research was arranged in randomized completely block design in factorial pattern with two factors, maize variety: local maize and hybrid corn bisi-2; and bokashi plus fertilizer doses: 0, 3, 6 and 9 t ha-1. Maize growth recorded were plant height, leaf number, stem diameter and leaf area at 2, 4, 6 and 8 WAP and maize yields recorded were cob weight with cornhusk, cob weight without cornhusk, cob length, diameter, row number, 100 seeds dry weight, biomass dry weight, yield and LER. The results showed that interaction between maize variety and bokashi plus fertilizer had significant effect on the growth and yield of maize intercropped with peanut under three years of teak trees in agroforestry system. The best effects of maize growth and yield were obtained at 9 t ha-1 with highest yield of local maize and hybrid maize of 4,69 and 5,79 t ha-1.

Pests and diseases on Falcataria moluccana trees in agroforestry systems with pineapple in East Java, Indonesia

Abstract. Rahayu S, Triyogo A, Widyastuti SM, Musyafa’, Ardianyah F. 2021. Pests and diseases on Falcataria moluccana trees in agroforestry systems with pineapple in East Java, Indonesia. Biodiversitas 22: 2779-2788. The agroforestry system using Falcataria moluccana (Sengon) and Ananas comosus (pineapple) is considered as a profitable intercropping system in Indonesia. To make it viable, it is necessary to evaluate the effect of mixed cropping on the incidence and severity of diseases and pests on Sengon trees and apply management measures. The present study was conducted (i) to assess the pest and disease problems on Sengon trees in the agroforestry system and (ii) to identify the most harmful pathogen/pest which affects the growth and causes mortality of Sengon trees at the beginning of intercropping and after the removal of pineapple from the system. Incidence of pests and diseases were assessed in 3 replicate blocks with one-year-old Sengon trees mixed with pineapple, and in another 3 plots with four-year-old Sengon trees from where pineapple was removed after harvesting. Sengon and pineapple were planted in the plots using alley cropping method with 3 x 4 m2 spacing. The results showed that there were no significant pest and disease problems on pineapple. However, Sengon was infested by the white grub Lepidiota stigma, gall rust caused by the fungus Uromycladium falcatarium, the stem borer Xystrocera festiva, and mistletoe Scurrula sp. However, stem borer and gall rust were the only pest and disease issues recorded in the monocultures of Sengon in Indonesia. The occurrence of stem borer and gall rust disease had a significant effect on the diameter growth of trees and in some instances, these caused mortality of one-year-old trees. Significant mortality of four-year-old trees was caused by mistletoe infestation only. Although the incidence of gall rust and stem borer in the agroforestry system was not significantly low compared to the monoculture, the former had wider spacing between trees, more open canopy and resultant low humidity and faster wind speed reduced the severity of the gall rust disease and stem borer attack. However, the intercropping resulted in the white grub attack on young Sengon trees which calls for application of contaminant-free fertilizers in pineapple plantings.

Modelling and Comparing Shading Effects of 3D Tree Structures with Virtual Leaves

Reduced solar radiation brought about by trees on agricultural land can both positively and negatively affect crop growth. For a better understanding of this issue, we aim for an improved simulation of the shade cast by trees in agroforestry systems and a precise estimation of insolation reduction. We present a leaf creation algorithm to generate realistic leaves to be placed upon quantitative structure models (QSMs) of real trees. Further, we couple it with an enhanced approach of a 3D model capable of quantifying shading effects of a tree, at a high temporal and spatial resolution. Hence, 3D data derived from wild cherry trees (Prunus avium L.) generated by terrestrial laser scanner technology formed a basis for the tree reconstruction, and served as leaf-off mode. Two leaf-on modes were simulated: realistic leaves, fed with leaf data from wild cherry trees; and ellipsoidal leaves, having ellipsoids as leaf-replacement. For comparison, we assessed the shading effects using hemispherical photography as an alternative method. Results showed that insolation reduction was higher using realistic leaves, and that the shaded area was greater in size than with the ellipsoidal leaves or leaf-off conditions. All shading effects were similarly distributed on the ground, with the exception of those derived through hemispherical photography, which were greater in size, but with less insolation reduction than realistic leaves. The main achievements of this study are: the enhancement of the leaf-on mode for QSMs with realistic leaves, the updates of the shadow model, and the comparison of shading effects. We provide evidence that the inclusion of realistic leaves with precise 3D data might be fundamental to accurately model the shading effects of trees.