The contribution of Cassia siamea hedgerows and mulch to erosion control was evaluated on a 14% slope of a Lixisol/Alfisol at Machakos, Kenya. The four treatments, in 400 m2 runoff-plots were: hedgerows with prunings applied as mulch to the crop, hedgerows and crops with prunings removed, mulch only applied to the crop and a control. The hedgerows were planted on the contour, 4 m apart and 0.25 m between plants. Maize and cowpea were planted in sequence. The control plot sustained an average annual water loss over 3 y of 31 mm runoff and soil loss of 19 t ha1. The best treatment, hedgerows with mulch, reduced losses to 13% and 2% of the control. Hedgerows without mulch reduced losses respectively to 23% and 7%, while mulch without hedgerows reduced losses to 41% and 17%. Soil loss was considerably influenced by one single storm in April 1990 due to the nature of that storm and to the susceptibility of the soil to erosion at that particular time. Differences in crop yield between treatments were small. The hedgerow treatments depressed cowpea yield slightly in less than normal rainy seasons but improved cowpea yields in wet seasons.
Tag: crop yield
Population, land tenure, and natural resource management: the case of customary land in Malawi
This paper uses cross section-time series data on 57 communities in Malawi to determine statistically the factors determining changes in land use, tree cover, and crop yield.The econometric model is developed from a theoretical model which also endogenizes population growth and prevailing land tenure institutions within the customary sector of Malawi. The analysis reflects changes between 1971 and 1995, utilizing aerial photos taken a t these dates and complementing these with field surveys. The data show a deterioration ofMalawi’s natural resource base: declining yields, loss of tree cover, and near exhaustion of land for agricultural expansion. Key findings are that population pressure induces landconversion but not yield or tree cover change; the matrilocal system of household residence is negatively associated with tree cover but induces agricultural conversion; and there is someimprovement in management of resources as their scarcity increases. Policy recommendationsinclude greater focus on agroforestry to increase tree cover as woodland areas are poorlymanaged, and increased effort to improve market integration since this benefits crop yieldswithout adverse effects on tree cover.
Proximity to natural habitat is not consistently associated with pollination services in tropical smallholder farms: A systematic review and meta‐analysis
Proximity to natural habitat is known to enhance pollination services in large‐scale agriculture, but it remains unclear whether this holds in tropical smallholder farms. These systems are embedded in ecologically complex landscapes, central to global food security, and depend heavily on biodiversity‐derived ecosystem services. We conducted a systematic review and meta‐analysis of 35 studies assessing the relationship between distance to natural habitat and pollinator abundance, species richness, and crop fruit set in tropical smallholder farms. We found no consistent patterns in pollinator abundance and crop fruit set with increasing distance, with relationships highly variable across studies. Similarly variable, yet slightly negative, was the relationship between distance and pollinator species richness. Our findings suggest limited support for the ‘proximity to natural habitat’ hypothesis in tropical smallholder farms, indicating that the inherent complexity of these landscapes may buffer negative effects of distance on pollination. This underscores the importance of maintaining and restoring landscape complexity to sustain biodiversity and ecosystem services such as crop pollination. We also highlight the need for greater methodological consistency and publicly available raw data in future studies to strengthen the evidence base and support management strategies for safeguarding pollination services in tropical smallholder farms.
Can improved plant nutrition buffer against water-related yield losses in oil palm?
Oil palm is the main source of vegetable oil in the world, with Indonesia accounting for 60 % of global production. Maintaining stable oil palm yields amidst changing climate is important given the implications for processing mills, supply chains, and socio-economic outcomes. Using monthly yield data collected over 7–9 years from four fertilization trials in water-limited environments in Indonesia, we assessed the impact of plant nutrition on the stability of oil palm yield. Each trial included three fertilization treatments (low, standard practice, and high) leading to differences in plant nutritional status across treatments as determined using leaf tissue analysis. Average yield was 77 % higher in the high- versus low-fertilizer treatments (27.1 and 15.3 t ha⁻¹, respectively), with temporal yield variation driven by water stress and vapor pressure deficit. Improved plant nutrition increased the yield response to favorable weather, leading to a concomitant increase in absolute yield variation (standard deviation and inter-quartile range), but smaller relative variation (coefficient of variation and sustainable yield index). On the other hand, improving plant nutrition had little impact on yield during low-yielding cycles due to water limitation. Despite the key role of plant nutrition to sustain high oil palm yields, our study shows limited room to stabilize yield and/or avoid climate-related yield losses. On the other hand, our findings suggest that future yield improvement will depend more on reducing yield constraints under favorable conditions, which will require greater flexibility to adjust field and mill operations to the larger yield variation.
System dynamics model for sustainable rice estate development to achieve food security with low carbon emissions
Key messages
- We developed a system dynamics model – sustainable rice estate for food security with low carbon emissions (SECURE) – to explore different scenarios and develop plans for food security, especially for rice, while minimizing the impact of carbon emissions.
- The baseline simulation shows a clear need for Indonesia to be food self-sufficient (swasembada pangan), particularly for rice. There will be a gap of 4.2 million metric tons of rice needs by 2030, and the gap will continue to increase after 2030. Climate change, increased population, and shrinking paddy rice fields widen the supply and demand gap.
- Our system dynamics model highlights that food estate development in Papua and Kalimantan requires caution as it could undermine Indonesia’s climate change commitment through FOLU (Forest and Land Use) Net Sink 2030, which aims to have net-zero emissions in 2030.
- Simulating conversion of convertible production forests (Hutan Produksi Konversi – HPK) to rice estates contributed to most of the emissions, including in Kalimantan and Papua. Although this is a legal conversion, our model shows that it will potentially emit 301 million metric tons of CO₂e, as HPK still consists of forest cover.
- We propose scenarios for food–climate solutions by examining land areas with fewer or no trees and developing rice food estates. In our simulation, the combination of rice planting in non-forested areas with increased rice yield productivity and staple food diversification is the best option to fulfil rice demand, along with reducing emissions.
- We identify institutional arrangements for this scenario under the current administration.
Influence of Eucalyptus camaldulensis Dehnh on the growth, productivity and physiology of three associated crops in the Sudano-Sahelian zone of Burkina Faso, West Africa
Eucalyptus camaldulensis Dehnh is an exotic species found in Sahel agroecosystems, often growing alongside annual crops. However, there is limited documentation regarding its ecological impacts on these crops. This study aims to assess the influence of eucalyptus on crop physiological traits and yield. To accomplish this, on-farm experiments were conducted over two years (2022 and 2023), employing a tree effect gradient called a gradient-based design with 4–7 replications for cowpea, millet, and sorghum. The experimental design included three plot locations based on their proximity to the eucalyptus trunk: one directly under the crown, another centred at 11 m, and a control plot situated 22 m away. Various parameters, such as height, relative chlorophyll content, leaf area index, photosynthetically active radiation, and yields of grain straw, were measured across all plots and years. Results from pairwise tests indicated significant differences among the plots for most parameters studied. Notably, plant height significantly decreased in proximity to eucalyptus (p < 0.000) throughout the two years. For relative chlorophyll content, the millet and sorghum in 2022 presented significant differences between plots located at 22 m and plots under the crown (p = 0.000). The photosynthetically active radiation indicated significant differences between the plot located at 22 m and the plot under the crown in cowpea, sorghum (2022 and 2023). Additionally, grain and straw yields were significantly lower near the eucalyptus in both years (p < 0.05). These findings suggest potential ecological risks associated with growing certain crops close to eucalyptus in the Sahel context.
Reproductive Biology of Tamarindus indica L.: Insights Into Floral Morphology, Pollination Ecology, and Breeding System
Tamarindus indica L. plays a crucial role in sustainable forestry and agroforestry systems due to its nutritional and economic potential. This study provides insight into the biology of reproduction in Tamarind and deals with its floral morphology, pollen biology, stigma receptivity, breeding system, and floral visitation. Comprehensive observations were conducted on five clonal selections across two flowering seasons. Tamarind is adapted to annual flowering with varying durations among individuals. Selections display notable variations in leaf flushing that corresponded with flowering and fruiting phases. Anthesis starts 11:00 p.m. and is complete by 4:00 a.m. Anther dehiscence occurs 3–4 hours after anthesis. Pollen is dimorphic (25–40 μm), with high pollen fertility (87.625 ± 3.20%). In vitro pollen germination studies indicate varying responses to gradient sucrose concentrations. The stigma is wet-papillate, peaking by 12:00 noon. Flowers are entomophilous, presenting pollen and nectar to over eight groups of visitors. Bees of the Apis genus, are the primary pollinators, foraging throughout the day. Breeding system studies indicate open pollination fruit set from 4.04% to 30.09%. Cross-pollination (xenogamy) yielded the highest fruit set percentages (75.31%–88.03%). Geitonogamy yielded minimal fruit set, and apomixis showed none, indicating self-incompatibility. Variations in phenology, floral traits, and fruit pulp coloration, such as the unique red pulp in some selections, highlight the genetic diversity of Tamarind. The findings underscore the importance of clonal selection for genetic conservation, pollination efficiency, and enhanced fruit yield in agroforestry systems.
Leucaena-Based Alley Cropping System: An Approach for Reclaiming Degraded Land, Reducing the Use of Inorganic Nitrogen Fertilizer, and Improving Crop Productivity
Alley cropping, an agroforestry system that integrates trees and arable crops, holds the potential to improve both crop yields and soil health. It has been found to be effective for upland crops in many countries of the world. However, the utilization of alley cropping to improve soil health in the terrace ecosystem of Bangladesh is poorly understood. Therefore, this study was undertaken to assess the changes in soil biochemical properties and quantify the cabbage yield under three alley widths of Leucaena leucocephala (3.0, 4.5, and 6.0 m size) and five nitrogen (N) levels [0, 40, 80, 120, and 160 kg N ha−1 (0, 25, 50, 75, and 100% of recommended N rates, respectively) with the addition of pruned materials of L. leucocephala (Ipil-ipil)]. The field experiment was conducted following a split-plot design, where alley width was considered as the main-plot factor and N rate as the sub-plot factor. Within each main plot, the five N rates were replicated thrice. Control plots with similar N doses were applied accordingly without addition of pruned materials to compare the results with alley cropping. Data were collected on the biochemical properties of the soil [soil pH, organic carbon (C), total N, available phosphorus (P), exchangeable potassium (K), microbial biomass C, and biomass N] and the yield of cabbage quantified [edible head weight (kg plant−1) and head yield (t ha−1)] under different alley widths and control. Findings revealed that organic C, total N, available P, exchangeable K, microbial biomass C, and biomass N in the topsoil exhibited maximum values in the L. leucocephala-based alley plot, which is proved to be a possible solution of restoration of degradable land. Additionally, L. leucocephala-based alley cropping improved the soil pH, indicating a potential avenue for more-sustainable land management practices. Results also showed that alley widths and N rates have significant effects on cabbage (Brassica oleracea L. var. capitata) yield. Alley width of 6.0 m along with 100% N provided the highest cabbage yield followed by 75% N in 6.0 m alley, and the control with 100%. The wider alley minimizes tree–crop competition, allowing for optimal cabbage production. These aforementioned results suggest that alley cropping with L. leucocephala is a promising approach to enhance soil fertility and crop productivity in the terrace ecosystem of Bangladesh.
Enhancing maize (Zea mays) productivity through integrated soil fertility management: a participatory approach in the degraded soils of Kigoma, Tanzania
Maize yields in sub-Saharan Africa remain low due to poor soil fertility, inadequate crop management, and erratic rainfall. This study evaluated the effects of integrated soil fertility management (ISFM) practices—using combinations of manure, lime, and NPK fertilizer—on soil chemical properties and maize yields. Conducted through participatory methods (InPaC-S), the study found that lime + NPK significantly improved yields by 149% and enhanced soil health indicators such as CEC, organic carbon, and nutrient content. While this treatment had the highest production cost, it also yielded the greatest net revenue. Sensitivity analysis revealed that rising fertilizer costs could reduce profitability, making alternative ISFM combinations (e.g., lime or manure alone) more viable. The findings support scaling up ISFM to improve food security and rural livelihoods across the region.
Soil moisture changes and maize productivity under alley cropping with leucaena and flemingia hedgerows at Chalimbana, near Lusaka, Zambia.
Soil moisture changes and maize yield were studied in 2-year-old alleys of Leucaena leucocephala and Flemingia macrophylla at Chalimbana, Zambia. Field tensiometers were installed at 15, 30 and 45 cm depth, in fertilizer and unfertilized alleys within the double hedgerows, and the first, second and third rows of maize, and were monitored throughout one maize growing season in 1989/1990. In general, maize growth (indicated by height and dry matter measured at roughly fortnightly interval) was higher (P <0.01) in fertilized alleys than in unfertilized alleys, and there were no differences between Leucaena and Flemingia alleys. In both fertilized and unfertilized alleys, the maize plants were 20% shorter (P <0.01) in the first row (nearer the hedgerows) than in the second and third maize rows. Maize dry matter yield was 30% more (P<0.01) in unfertilized Flemingia alleys than in corresponding Leucaena alleys. The grain yield was similar in the fertilized alleys of Leucaena and Flemingia. However, in unfertilized alleys, the grain yield in Flemingia alloys was 50% more than that of the corresponding Leucaena alleys. The fertilized alleys produced twice as much grain as unfertilized alleys when hedgerow prunings were added to the plots. The prunings as a source of nutrient did not appear to have any noticeable effect on crop productivity. The soil moisture content under both Leucaena and Flemingia hedgerow was higher than under the maize rows in the alleys throughout the growing season. The study shows that, under conditions of low fertility and no addition of fertilizers, Leucaena is twice as competitive, as Flemingia for soil resources, and reduces yield of alley-cropped maize from 2.2 t ha1 to 0.7 t ha1. If, however, fertilizer is added, there are no short-term differences between the two hedgerow species.