The commercial plantation of agar trees has been increasing in the Brahmaputra floodplain under the greater Mymensingh region of Bangladesh. Agar plantation in the plainland allows enough space for cultivating different crops in between the two rows of agar trees. The present field study transformed a commercial agar (Aquilaria malaccensis Roxb.) plantation into agroforestry systems, where the performance of winter vegetables (radish, spinach, broccoli, and tomato) and the annual crop papaya were evaluated at different distances from the tree row. Afterward, it was compared with their respective non-agroforestry sole crops planted in open-field (control) conditions. The findings of the investigation revealed that the yield reduction for radish, spinach, broccoli, and tomato was 40%, 58%, 37%, and 40%, respectively, in agroforestry systems compared to the control. The yields of the seasonal crops were boosted with increasing planting distances from tree rows. These findings also indicated that the light intensity, which is indispensable for crop production, was highly interfered with in the agroforestry system by the straight canopy structure of agar trees. Though having some adverse impacts on yield performances of seasonal crops, the net return, benefit–cost ratio (BCR), and land equivalent ratio (LER) were greatly higher in agar-based agroforestry systems compared to non-agroforestry systems. Compared to non-agroforestry control plots, the total nitrogen, phosphorus, and potassium content in agroforestry systems was 41%, 27%, and 150% higher, respectively. Thus, it can be concluded that the Aquilaria plantation can be transformed into an agroforestry system to ensure higher income, optimum land use, and soil fertility status, and sustain food security.
Tag: cropping systems
Reducing emissions from all land uses – REALU. An approach toward reduce emission from deforestation and degradation (REDD/REDD+) and national appropriate mitigation action – NAMA (in Vietnam language)
This sourcebook provides a consensus perspective from the global community of earth observation and carbon experts on methodological issues relating to quantifying the greenhouse gas (GHG) impacts of implementing mitigation activities related to the forest land use in developing countries (REDD+). At current status of negotiation five forest-related activities have been listed to be implemented as mitigation actions by developing countries, namely: reducing emissions from deforestation (which implies a land-use change) and reducing emissions from forest degradation, conservation of forest carbon stocks, sustainable management of forest land, Enhancement of forest carbon stocks (all relating to carbon stock changes and GHG emissions within managed forest land use, including forest expansion on non-forest land). The UNFCCC negotiations and related country submissions on REDD+ have advocated that methodologies and tools become available for estimating emissions and removals from deforestation and forest land management, including forest expansion, with an acceptable level of certainty. Based on the current status of negotiations and UNFCCC approved methodologies, the Sourcebook aims to provide additional explanation, clarification, and methodologies to support REDD+ early actions and readiness mechanisms for building national REDD+ monitoring systems. It complements the Intergovernmental Panel on Climate Change (IPCC) 2006 Guidelines for National Greenhouse Gas Inventories and it is aimed at being fully consistent with this IPCC Guidelines and with the UNFCCC reporting guidelines on annual GHG inventories. The book emphasizes the role of satellite remote sensing as an important tool for monitoring changes in forest cover, provides guidance on how to obtain credible estimates of forest carbon stocks and related changes, and provides clarification on the use of IPCC Guidelines for estimating and reporting GHG emissions and removals from forest lands.
The effect of short rotation Sesbania sesban planted fallows on maize yield.
Two provenances of Sesbania sesban var. nubica (Kakamega and Chipata) were planted in fallows for 1, 2 and 3 years at 0.5 m × 0.5 m, 0.7 m × 0.7 and 1.0 m × 1.0 m spacing. Maize crop (MM604) was grown after fallow period at 0, 37, 74 and 112 kg N ha1 to evaluate the effects of nitrogen (N) and fallow on grain yield. There were no significant differences between the two provenances of S. sesban. Wood biomass after 1, 2 and 3 years fallow at close spacing was 8.3, 17.6 and 21.4 t ha1 for the Kakamega provenance and 10.8, 14.5 and 21.2 t ha1 for the Chipata provenance. Litter fall in both provenances ranged from 0.6 t ha1 in June to 0.01 t ha1 in November. Stand mortality increased with plant density and fallow years: 27% in the first year and about 90% by the end of the third year. Weed biomass ranged from 6.8 t ha1 to 6.0 t ha1 at close and wide spacing respectively.Maize grain yield without N was 2.27, 5.59 and 6.02 t ha1 after 1, 2 and 3 years fallow respectively compared with the control plots with 1.6, 1.2. 1.8 t ha1 after 1, 2 and 3 years of continuous cropping. Even with addition of 112 kg N ha1, yield in the control plots declined from 6.09 to 4.88 and 4.28 t ha1 after 1, 2 and 3 years of continuous cropping. In the planted fallows at 112 kg N ha1, maize yield increased from 6.75 to 7.16 and 7.57 t ha1 following 1, 2 and 3 years fallow. It is concluded that short fallow rotations of 1–3 years using S. sesban have a potential in increasing maize yield even without fertilizers. Thus, increasing the fallow period decreases the effectiveness of inorganic fertilizers but increases grain yield for low fertilizer input.
Distribution, ecology and management of Chromolaena odorata: proceedings of the Third International Chromolaena Workshop, Abidjan, Cote d’Ivoire, November 1993
The perennial shrub Chromolaena odorata (L.) King and H.Robinson, was first introduced intoWest Africa in the late 1930s. It has since spreadrapidly throughout West and Central Africa, from Guineato northern Angola and central Zaire. C. odorata has become a troublesome weed in open spaces, clearings around humansettlements, in early secondary succession, crop andpasture lands, and in young tree crop plantations
The ongoing journey of modelling intercropping systems: A conceptual resource sharing intercomparison from model developers and expert users
Context
The global shift toward sustainable agriculture has increased interest in using process-based models to design and optimize intercropping systems. However, these models differ fundamentally in how they represent trade-offs (competition for light, water, and nutrients) and synergies (facilitation, complementarity) in resource sharing between species. This conceptual variation creates uncertainty in model selection and application, particularly since most models were originally developed for monoculture and subsequently adapted for intercropping.
Objective
In this study, we describe how current crop models represent interspecies resource-sharing mechanisms, analyse their structural differences, and synthesize findings from existing validation studies to understand how their structural differences affect model performance. The models examined include APSIM (APSIM-Canopy, APSIM-Micromet, APSIM-Strip, APSIM-Alternating, APSIM-APSwim, APSIM-SoilArbitrator), DayCent, DSSAT-Mixed, DSSAT-MPI, LandscapeDNDC, LUCIA, MONICA, SIMPLACE Lintul5-Intercrop, STICS-Big-Leaf, STICS-Multilayer, and WaNuLCAS.
Methods
Through the Agricultural Model Intercomparison and Improvement Project (AgMIP) platform, we engaged with model developers and expert users to collect detailed information on how crop models represent intercropping systems using structured interviews and questionnaires. We then developed a framework that groups models by their core conceptual approaches to simulating resource sharing. Finally, we synthesize findings from existing quantitative validation studies to connect conceptual intercomparison to predictive performance across different intercrop characteristics and environments.
Results and Conclusions
Our analysis identifies six distinct conceptual approaches for simulating light sharing and four for belowground resource (water and nutrient) competition. Intercrop models show greater structural divergence in canopy than in belowground representation. Furthermore, competitive trade-offs (light, water, and nutrients) are widely represented while facilitative and other complex processes like N₂-fixation, plasticity (shoot and root), microclimate effects or hydraulic lift are often simplified or omitted. Our analysis of model validation studies reveals a critical trade-off: structurally complex models often perform well in simulating intercropping when calibration is done on sole crops, whereas simpler models require extensive intercrop-specific calibration to achieve better prediction performance. This distinction is vital for model application in data-scarce environments, as more complex architectures can leverage existing sole-crop data to effectively simulate intercrop systems. The classification of the structural resource capture differences in combination with the evaluated model performance analysis allowed us to devise an evidence-based model selection criteria framework useful also for for non-specialist, while the unique detailed description provided are highly valuable for the model research community.
Significance
This study establishes a conceptual framework that provides the necessary foundation for a meaningful quantitative intercomparison of intercrop models, as structural understanding enables the interpretation of numerical differences in model outputs. It also guides hypothesis testing, model choice, priorities in model development and improvements.
Co-designing technical innovations in the context of agricultural living landscapes
Codesign was a major focus of work package 1 that deals with the Transdisciplinary co-creation of innovations in Agroecological Living Landscapes (ALLs) in the target countries during 2023. This report provides an overview of progress achieved in 2023 with respect to codesign of technological innovations in 7 countries (Zimbabwe, Kenya, Tunisia, Burkina Faso, Senegal, Peru, Laos). It highlights the commonalities, contrasts and originalities among them in terms of actual approaches, existing practices, types of technologies selected for experimentation, experimental set-ups and monitoring and evaluation protocols. Hardly any experimental results per se are presented, as most countries did not yet have time to process them.
Production and decay of structural root material of winter wheat and sugar beet in conventional and integrated cropping systems
Production of structural root material of sugar beet and winter wheat was quantified by analysis of root growth and decay in a time series of minirhizotron images, combined with a single auger sampling. Cumulative root production of winter wheat was about 1700 kg ha1 for conventional crp management and 1960 kg ha1 for integrated (less pesticides and mineral fertilizer, less intensive soil tillage and more organic manure) crop management; in 1990 the difference between the two management systems was statistically significant. At harvest time 85% and 68% (in 1986 and 1990, respectively) of this structural root production remained as intact roots in the soil in both management systems. For sugar beet total fine root production was estimated at 1150 kg ha1 in 1987 and 1989, with a significantly lower amount on the field on which minimum tillage was introduced in 1986; on average 47% of total root production remained as intact roots at harvest.Winter wheat root decay was studied with litter pots after crop harvest and in the following growing season. Initially, the N concentration in remaining roots increased while dry weight decreased. No net immobilisation or mineralisation of N and P during autumn was evident. During the next growing season net mineralisation was proportional to loss of root weight in an exponential decay with a half-life of 600 degree days (daily temperature sum). This N release pattern during the next growing period thus contributes to the synchrony between N demand and supply, but no difference between the two management systems was found.
Factors influencing adoption and use of Tephrosia vogelii in Malawi: Role of by-laws and other drivers
Soil nutrient deficiency poses great challenge to efforts aimed at improving agricultural productivity in Southern Africa. Agroforestry fertilizer tree technologies have potential to improve soil productivity in cropping systems. As such understanding the socio-economic and biophysical drivers in promoting adoption, and use of Tephrosia vogelii (T. vogelii) would provide requisite knowledge to stakeholders who promote integration of fertilizer tree technologies. This study conducted an analysis of effectiveness of by-laws, other socio-economic drivers, and biophysical factors in promoting the adoption and use of T. vogelii in Kasungu district in the central region of Malawi. The study used multistage sampling technique and data from 432 farmers. A Double Hurdle model was used where Probit regression and Truncated regression models were incorporated in the first and second hurdle, respectively. The study found that by-laws, seed availability, frequency of extension officer’s visits before planting, technology provider and field characteristics influenced adoption and utilization intensity of T. vogelii in Kasungu district, Malawi. Awareness creation on developed by-laws and enforcement, promoted the adoption of intercropping of T. vogelii in the maize-based cropping system.
Rooting depth in cropping systems in the humid tropics in relation to nutrient use efficiency
A simple model is presented for calculating the rooting depth of a crop or crop combination required to intercept leaching nutrients for different climatic and soil conditions. Important parameters in this model are the amount of water moving through the soil, which depends on excess of rainfall over evapotranspiration, and the apparent adsorption constant, which depends on the nutrient and soil type involved. Calculations for three time patterns of nutrient supply in relation to nutrient demand show moderate effects of the degree of synchronization on rooting depth required if a high interception fraction is desired. In shifting cultivation systems a deep-rooted fallow vegetation can recover nutrients leached to the subsoil during the cropping phase. The simple leaching model can indicate the combinations of climate zone and apparent adsorption constant for which such interception is possible. It appears that recovery of leached nitrate is only possible in the subhumid zone. In the humid tropics the continuous presence of a deep root system as part of the crop combination on the field is necessary to use nitrogen efficiently, except when acid soil conditions keep all nitrogen in the ammonium form or when an almost ideal synchronization exists of nitrogen supply and demand during the growing season. Some data are discussed on the root distribution of food crops and on the possibilities to establish a “safety-net” under the crops grown in alleys between deep-rooted hedgerow trees.