Crop Cycle Research Articles

Rainy season and crop calendars comparison between past (1950–2018) and future (2030–2100) in Madagascar

AbstractThis paper analyzes rainfall data to characterize the rainy season and define rice and maize crop calendars for current and future conditions in Madagascar. The daily rainfall data are taken from observational climate records and climate model simulations from the CMIP6 under the SSP245 and SSP585 scenarios. Rainy season characteristics are calibrated to fit rice and maize crop growth stages. The comparison between the past (1950–2018) and the future (2030–2100) highlights changes in the onset and cessation dates, which happen later and earlier, respectively. This causes the reduction of the rainy season duration, which affects the rice and maize crop calendars, especially its sowing or seeding periods. The worst (best) case is mainly observed in the southeast (southwest). On the one hand, the southwestern region may need to adapt to grow rice and maize crops with short or medium crop cycles in the future. In the Highland or Central land, the length of the sowing or seeding period increases. On the other hand, the North and East face a significant reduction in the length of the sowing or seeding period. Rice endures more than maize. Growing rice crops twice a year may not be possible in the future. But rather, we observe minor changes in the West. Our analysis suggests the imperative necessity to advise smallholder farmers to rely on short crop cycle varieties of rice and maize crops. Predominantly, the harvesting period is postponed. It is recommended to carefully consider our results for the definition of food policies.

Morfometria e rendimento de palma forrageira 'Gigante' sob irrigação e diferentes densidades de plantio

ABSTRACT Growing forage cactus pear in semi-arid regions is an alternative when facing current climate changes, and improving its cropping systems is critical to increasing its yields. The objective was to evaluate morphometric characteristics and yield of ‘Gigante’ cactus pear under complementary irrigation with saline water and different planting densities. The research was carried out in the semiarid region of Bahia during the period from September 2017 to October 2019. A randomized block design was used with treatments arranged in split-split plots. Two irrigation intervals (7 and 14 days) were assigned to plots, four planting densities (20,000; 40,000; 60,000 and 80,000 plants per hectare) to subplots, and four irrigation levels (0, 11, 22 and 33% of ETo) to sub-subplots. High-salinity water (2.91 dS m-1), classified as C4S1, did not limit the growth and yield of ‘Gigante’ forage cactus pear for two crop cycles. Fresh matter and dry matter yields, fresh matter-based water use efficiency and dry matter-based water use efficiency were highest at planting densities of 61,465 and 67,786 plants ha-1, and 61,848 and 69,707 plants ha-1, respectively. The use of 33% ETo irrigation level increased morphometric characteristics, fresh matter yield in the first and second cycles, and dry matter yield in the first cycle. Applying increasing irrigation levels promotes reductions in fresh matterand dry matter-based water use efficiency.

English

Crop mapping and its health monitoring are of key importance for a country like Pakistan where a considerable share of the GDP originates from agricultural production. Currently, extensive capital and human resource are utilized to record the crop types and monitor crop health due to variations in crop pattern and intercropping practices being observed in many parts of the country. Satellite Remote Sensing, however, can be utilized very efficiently to identify crop types and estimate acreage by using unique phenological cycles derived from NDVI thresholds. In this research, we proposed a semi-automated, efficient and cost-effective state-of-the-art technique for crop classification using satellite remote sensing datasets and GIS techniques to replace outdated conventional survey-based crop estimations procedures. This research was conducted in Sahiwal district, Pakistan to categorise several crop types using two major inputs: satellite (Sentinel-2, 10m) imagery and local crop calendar. The research adopted a semi-automatic approach to find the main crops of Rabi (winter) and Kharif (summer) using orthorectified and atmospherically corrected Level-1C images to extract phenological information based on Normalized Difference Vegetation Index (NDVI). The complete phenological life cycle of crops including sowing, growing, and harvesting stages were deeply analyzed with the help of crop calendar and NDVI profiles. Then this information passed through iterative selforganizing (ISO Data Model) of unsupervised classification technique in the form of temporal stacked images. The NDVI profiles of each crop were synchronized with the crop calendar of the study area to develop the crop categorization procedure. The results were validated with the statistics of the agriculture department Lahore and field samples gave about 85% and 88% accuracy for Rabi and Kharif cropping seasons respectively. It is concluded from the research that the tested methodology is capable of providing a fast, cost-efficient, and reliable solution for crop mapping instead of conventional survey-based crop area assessment techniques (conventional Girdawri) which requires a vast number of resources and time, and it can be replicated in different areas with minor changes

Produção da pereira cv. Triunfo sob sistemas e lâminas de irrigação no submédio São Francisco

ABSTRACT Aiming at the search for a new alternative for the sustainability of the properties in the irrigated areas of the Brazilian Northeast, the objective of this study was to identify the ideal irrigation system and depth for a better yield and quality of pear fruits in the Sub-middle São Francisco region. The experiment was conducted in the commercial orchard of the Frutos do Sol farm, located in the municipality of Petrolina, PE, Brazil, from October 2016 to November 2017. The treatments consisted of four irrigation depths (60; 80; 100 and 120% of crop evapotranspiration - ETc), under two irrigation systems (drip and micro-sprinkler), in two crop cycles of ‘Triunfo’ pear. Yield, average fruit weight, water productivity, pulp firmness and titratable acidity, total soluble solids and lightness of the fruits were analyzed. Irrigation depths of 96.04% and 94.84% ETc promote, respectively, the highest marketable yields for the first (43.48 t ha-1) and second (26.55 t ha-1) cycle of ‘Triunfo’ pear in the Brazilian semi-arid region. Drip irrigation system in the warmer period promotes higher yield. The cultivation of ‘Triunfo’ pear irrigated by drip and micro-sprinkler promotes fruits with good commercial quality in the Brazilian semi-arid region.

How agrometeorological and water deficit variations influence the growth and yield of sugarcane

Edaphoclimatic variables play a crucial role in shaping both the growth and yield of sugarcane. This study aimed to evaluate the intricate relationships among plant variables, agrometeorological factors, and water stress conditions in three successive crop cycles of sugarcane (cane plant, ratoon 1, and ratoon 2). The investigated plant variables included stem height, stalk diameter, number of tillers, leaf area, leaf area index, and stalk fresh yield, alongside growth rates (growth/time). Concurrently, climate variables, such as air temperature, humidity, rainfall, wind speed, solar and net radiation, reference evapotranspiration, and degree-days, were monitored. Additionally, water stress parameters, including water deficit and water surplus, were quantified. Statistical models were skillfully fitted (r2 > 0.90) to the biometric data, employing thermal time as a critical determinant. Surprisingly, no adverse agrometeorological or soil moisture conditions, as indicated in the literature, were detected when growth rates started to decline. This suggests that other unmeasured stress factors may have influenced the plants during that period. The analysis of the ratio between actual and maximum crop evapotranspiration (ETa/ETc) revealed the most pronounced sensitivity to water deficit during the vegetative growth phase (phase III). Moreover, the study identified that growth achieved satisfactory levels when at least 60% of the maximum crop evapotranspiration was met during the initial phases. A comprehensive cluster analysis encompassing height, leaf area, leaf area index, relative air humidity, soil moisture, and actual evapotranspiration rates provided valuable insights into the interrelated dynamics of these variables. Furthermore, a significant exponential reduction in yield was observed as the number of harvests increased. This decline in yield was attributed to the combined effects of 50% of biometric variables, 63% of agrometeorological variables, and 50% of water stress variables, all of which exhibited negative correlations with yield. Approximately 82%, 63%, and 71% of the correlations among biometric, agrometeorological, and water stress variables, respectively, were strong or very strong (r ≥ 0.70). As a result, this study highlights that: i) estimating sugarcane growth and tracking its developmental stages can be accomplished by employing appropriate models based on thermal time; ii) most biometric measurements exhibit correlations of r < 0.70 with agrometeorological variables; iii) an integrated understanding of biometric, agrometeorological, and water stress variables can effectively explain the observed reductions in sugarcane yield

Effect of genotype-environment interaction on soybean (Glycine max (L.) Merrill) germination, vigor index, and seed yield

The adverse edaphoclimatic conditions in the Orinoquía region affect the soybean crop cycle, deteriorating seed quality. The aim of this study was to investigate the effect of the genotype (G), the environment (E), and their interaction (GxE) on the yield and seed quality of six soybean varieties (Corpoica Superior 6, Orinoquía 3, Soyica P34, Corpoica Taluma 5, and Agrosavia Primavera 11 of Colombian origin and Barreira of Brazilian origin) in five environments of the Orinoquía Colombia region, two in the second half of 2020 (LIBB: La Libertad and TALB: Taluma) and three in the first half of 2021 (LIBA: La Libertad, TALA: Taluma, and LEONAS), to determine their adaptation domain. Highly significant differences (P<0.01) were observed between G, E, and GxE for germination (GER) and seed yield (SY). A similar situation was shown by the vigor index (VI), although without differences between environments. The GGE biplot for GER, and SY separated environments by year halves. Taluma during the first half was the most discriminating environment for the response variables, useful for genetic breeding programs with a seed quality approach. Only in La Libertad during the second half was GER above 80%. The most stable variety per environment was Soyica P34 in two response variables, and the best with specific adaptation were Corpoica Superior 6 and Orinoquía 3. These last two reached higher average values in GER (69.6%; 63.1%), VI (13.3; 13.4), and SY (1473 kg ha-1; 1404 kg ha-1).

Behaviour of five banana cultivars in their first cropping cycle under permanent cover of tree species, legumes and non-legumes, and fruit trees in Kinshasa, DRC

Pour améliorer la production des bananes à Kinshasa, une étude évaluative des systèmes sylvo-bananiers a été menée dans les conditions du plateau des Batéké. Il était question de comparer les différentes associations de bananiers avec les espèces arborescentes, en vue de connaitre leur impact sur la productivité des bananiers. Cinq cultivars de bananiers ont été associés avec douze essences arborescentes, réparties en trois groupes : forestières légumineuses arborescentes, forestières arborescentes non-légumineuses et arbres fruitiers. Les bananiers ont évolué sous couverture de ces agroforêts et leur comportement a été systématiquement évalué au cours de leur premier cycle de production. De tous les cultivars de bananiers mis sous étude, le cultivar Nsikumuna était le plus productif (rendement, poids de régimes, poids de doigt, etc…) en association avec toutes les essences forestières ; suivi des cultivars Gros Michel (en association avec Pterocarpus indicus Willd, Millettia laurentii et Inga edulis) et Ndongila (en association avec P. indicus Willd). Cependant, le cultivar Bubi s’est révélé moins productif en association avec toutes les essences forestières considérées par rapport à tous les autres cultivars. Ce travail est un outil qui peut contribuer à la promotion des pratiques et technologies agroforestières/sylvo-bananières, lesquelles pourraient être appliquées par les producteurs de bananiers œuvrant dans la zone sud-ouest du pays.

Evaluation of the productivity of banana plants in the second crop cycle, planted in a corridor of leguminous trees on the Batéké Plateau (Kinshasa, DR Congo)

Dans le contexte de changement climatique, le système sylvobananier est une réponse favorable d’une part aux problèmes de l’intensification de la production de bananes, à la préservation des forêts, surtout dans les régions où la déforestation est accrue d’autre part. L’objectif de cette étude était d’améliorer la production de bananiers au plateau des Batéké. Cinq cultivars de bananiers ont été intégrés en culture intercalaire avec quatre légumineuses forestières arborescentes âgées de deux ans. Après la récolte du premier cycle, les pieds reproducteurs ont été remplacés par les rejets successeurs. Les analyses multivariées, particulièrement, l’analyse en composantes principale (ACP), a permis de démontrer la corrélation existante entre les associations bananiers-légumineuses arborescentes et les caractéristiques des rejets successeurs des cultivars de bananiers évaluées. Au regard des résultats obtenus, il est à noter que les associations formées avec les légumineuses arborescentes Pterocarpus indicus Wild, Milletia laurentii et Inga edulis Mart se sont révélées les plus performantes au deuxième cycle cultural de bananier, il s’agit respectivement des associations : Nsikumuna avec Pterocarpus indicus Wild ; suivi de Nsikumuna avec Milletia laurentii et de Gros Michel avec Pterocarpus indicus Wild. Ces combinaisons peuvent être recommandées aux producteurs afin de rentabiliser et de pérenniser la production de bananes dans le plateau de Batéké. Cependant, la contreperformance a plus été observée sur les associations formées avec l’espèce Acacia auriculiformus Benth.

Effects of Root Growth of Deep and Shallow Rooting Rice Cultivars in Compacted Paddy Soils on Subsequent Rice Growth

Rice is often grown as multiple seasons in one year, alternating between flooded and upland systems. A major constraint, introduced from the flooded system, is a plough pan that may decrease rooting depth and productivity of follow-on upland rice. Roots penetrating the plough pan under flooded rice system can leave a legacy of weaker root growth pathways. Deeper rooting rice cultivars could have a bigger impact, but no direct evidence is available. To explore whether a deep rather than a shallow rooting rice cultivar grown in a flooded cropping cycle benefited deeper root growth of follow-on rice in an upland, reduced tillage cropping cycle, a simulated flooded paddy in greenhouse was planted with deep (Black Gora) and shallow (IR64) rooting cultivars and a plant-free control. Artificial plough pans were made in between the topsoil and subsoil to form different treatments with no plough pan (0.35 MPa), soft plough pan (1.03 MPa) and hard plough pan (1.70 MPa). After harvest of this ‘first season’ rice, the soil was drained and undisturbed to simulate zero-tillage upland and planted rice cultivar BRRI Dhan 28. The overall root length density (RLD), root surface area, the numbers of root tips and branching of BRRI Dhan 28 did not vary between plough pan and no plough pan treatments. Compared with the shallow rooting rice genotype, the deep rooting rice genotype as ‘first season’ crop produced 19% greater RLD, 34% greater surface area and 29% more branching of BRRI Dhan 28 in the subsoil. In the topsoil, however, BRRI Dhan 28 had 28% greater RLD, 35% greater surface area and 43% more branching for the shallow rather than deep rooting genotype planted in the ‘first season’. The results suggested that rice cultivar selection for a paddy cycle affects root growth of a follow-on rice crop grown under no-till, with benefits to subsoil access from deep rooting cultivars and topsoil proliferation for shallow rooting cultivars.

Pyruvate supplementation in cotton under water restriction varying the phenological phases

Cotton is one of the largest agricultural commodities that generate various sources of foreign exchange and employment worldwide. However, water deficiency is an environmental factor that limits the production of this crop, especially in semi-arid regions. We evaluated pyruvate supplementation to mitigate the effects of water stress on colored cotton. Experiments were conducted in a greenhouse. We studied two forms of pyruvate supplementation (SP1- via seed and foliar and SP2- only via foliar); three conditions of irrigation management of the plants: water restriction in the vegetative phase (VE), flowering (FL), and vegetative and flowering (VE/FL); and additional treatment (total irrigation throughout the crop cycle and without pyruvate supplementation). The experimental design included a randomized block in a 2 × 3 + 1 factorial scheme. The factors resulted in seven treatments with three replications, with a total of 21 experimental units. Gas exchange, enzyme activity, and production of components were evaluated. Water restriction in the vegetative phase does not cause losses in BRS Jade cotton when supplemented with pyruvate. However, in the flowering and vegetative phases plus flowering, it reduces gas exchange and production components and increases the activity of antioxidant enzymes in relation to plants under full irrigation. Supplementation with pyruvate via seed plus foliar (SP1) was better for BRS Jade cotton grown under water restriction.

Potassium Increases Nitrogen and Potassium Utilization Efficiency and Yield in Foxtail Millet

Field experiments were conducted to investigate the effects of K application on the nitrogen and potassium utilization efficiency and yield of foxtail millet (Setaria italica L.). The experiment was performed with a completely randomized design with two millet cultivars (Jingu 21 and Zhangza 10) and five K2O rates (0, 60, 120, 180, and 240 kg/hm2) in 2020 and 2021. We found that K promoted K and N absorption; significantly increased dry matter (DM), N, and K accumulation in millet organs; caused dry matter accumulation to peak earlier; and increased the DM accumulation rate. In addition, K accumulation preceded that of DM or N. Relative to the crop cycle, most K (61.07%) accumulated at booting, whereas N accumulated mostly (33.86%) during grain filling. N absorption efficiency increased by 31.87%, and the apparent and agronomic utilization rate of K fertilizer remained high, increasing millet yield, which peaked at a K rate of 180 kg/hm2 for both cultivars, by 29.91% and 31.51% in Jingu 21 and Zhangza 10, respectively, relative to untreated controls. Stepwise regression and path analysis showed that the leaf and spike K accumulation, stem N accumulation, and stem DM were the main factors affecting yield, with DM having the greatest direct effect, followed by leaf K accumulation. The K concentration (0.77–3.04%) in Zhangza 10 was higher than that in Jingu 21 (0.69–2.91%) in untreated plants. Under the same K application rate, N and K accumulation and the harvest index were higher for Zhangza 10 than those for Jingu 21, and the nutrient utilization ability was greater for Zhangza 10. The results demonstrated that rational K fertilizer application can increase K concentration and accumulation in leaves, promote N metabolism and accumulation, increase N and K utilization efficiency, and improve DM accumulation and millet yield.

A robust approach for large-scale cropping intensity mapping in smallholder farms from vegetation, brownness indices and SAR time series

Multiple cropping is a widespread agricultural intensification for increasing food production. National-scale Cropping Intensity (CI) mapping is important for achieving sustainable development goals. However, previous studies have largely relied on vegetation indices (VI) waves for detecting valid cropping cycles, which is challenged by the complexity of agricultural systems. i.e. winter crops with multiple VI waves and double rice with less distinctive waves. This study proposed a robust framework for Mapping cropping Intensity through better-characterizing crop Life cycles based on combined considerations of vegetative and productive Stages (MILS). The number of cropping cycles was estimated by the frequency of valid coupled patterns of vegetation and brownness indices from Sentinel-2 (S2) MultiSpectral Instrument (MSI) time series and further improved through fusing Sentinel-1 (S1) SAR and S2 data to reduce the omission errors of double rice. The MILS algorithm was implemented using the Google Earth Engine platform and applied to China, which is dominated by smallholder farms with diverse cropping patterns. This study produced the first 10 m updated CI map over conterminous China (CIChina10m) in 2020 by fusing S1 and S2 time series. The CIChina10m had an overall accuracy of 93.93% when validated with 14,468 widely spread reference sites. The cropping intensity was 1.2769 on the national scale, which illustrated higher values in the Middle and lower reaches of the Yangtze River plain (CI = 1.5879) and South China (CI = 1.5503). There were 1086,620, 412,620 and 1,441 km2 areas cultivated by single, double and triple cropping in China, which accounted for 72.4%, 27.5% and 0.1% of cropland, respectively. The proposed MILS algorithm showed good performances in detecting complex agricultural systems, which can be further applied to generate continental or global 10-m CI products with good quality. Codes of the MILS algorithm are publicly available at https://code.earthengine.google.com/a7f24f76291bf901ee25a130025a7ce6, and the first 10m national CI data products in China with good accuracy (ChinaCI10m) are also publicly accessed at https://doi.org/10.6084/m9.figshare.23939505.

Soil Greenhouse Gas Emissions in Intercropped Systems Between Melon and Cowpea

There is a need to assess alternative cropping systems for climate change mitigation. Hence, we aimed to evaluate if cowpea, a legume crop with high climate adaptability and active rhizodeposition, can reduce GHG emissions when intercropped with melon, if different intercropping patterns can affect these soil GHG emissions, and elucidate if GHG emissions are related by soil and crop properties. We compared a cowpea and melon monocultures with different melon-cowpea intercropping patterns during two crop cycles. The different melon-cowpea intercropping patterns were: row intercropping 1:1 (melon:cowpea), row intercropping 2:1 (melon:cowpea) and mixed intercropping (alternate melon/cowpea plants within the same row), receiving 30% less fertilizers than monocrops. Results showed that CO2 emission rates were higher in the row 2:1 and row 1:1 intercropping systems compared to mixed intercropping, melon monocrop and cowpea monocrop, with the lowest emissions, likely due to the highest density of both plant species, which may stimulate microbial communities. Soil N2O emission rates were not affected by crop diversification, with very low values. Soil CO2 and N2O emissions were not correlated with environmental factors, soil properties or crop yield and quality, suggesting that crop management and plant density and growth were the main factors controlling GHG emissions. When the GHG emissions were expressed on a crop production basis, the lowest values were observed in mixed intercropping, owing to higher crop production. However, the 1:1 and 2:1 cowpea intercropping systems, with the lowest overall crop production, showed higher values of GHG emissions per unit of product, compared to cowpea monocrop. Thus, intercropping systems, and mostly mixed intercropping, have the potential to contribute to sustainable agriculture by increasing land productivity, reducing the need for synthetic fertilizers and decreasing GHG emissions per unit of product. These results highlight the importance of considering both agricultural productivity and greenhouse gas emissions when designing and implementing intercropping systems.

DIVERSIDAD DEL MAÍZ EN TRES ZONAS GEOMORFOLÓGICAS DE YUCATÁN, MÉXICO

<p><strong>Background: </strong>Maize (<em>Zea mays</em> L.) is the main sustenance in the daily diet of Mexican families. As a crop, it is one of the most important in the country of Mexico, and in Yucatan state, it is grown under rainfed conditions in milpas with no mechanizable lands. In this study, an analysis of the phenotypic variability from cob collects of native maize from Yucatan state was carried out, with ethnobotanical information collected within passport data. <strong>Objectives:</strong> To introduce the genetic diversity of maize into a germplasm bank, to know the genetic diversity of native populations based on the characteristics of cob, to know its distribution, to find the potential populations in each collection area for its use in genetic improvement programs. <strong>Methodology: </strong>66 Tuxpeños, 13 Dzit bacal, 6 Nal tel, 13 Xmejen nal, and 2 Nal xoy were collected in the southern, central, and eastern regions of the state, from January to March 2020, by sampling the four cardinal points in each community visited. A vector map of collections in Yucatan was developed and quantitative data of 13 biometric cob variables were recorded in 100 populations (crop cycles: late n=68; intermediate n=26; early n=6), a general data analysis of variance (ANOVA) and by crop cycles were made, principal component analysis (PCA), hierarchically clustered with the average linkage method and discriminant analysis were made. Qualitative data from ethnobotanical surveys with mixed questions applied to milperos at the time of collection are presented. <strong>Results: </strong>The diversity of native maize in Yucatan is made up of three main groups based on the crop cycle: late, intermediate, and early. The southern and eastern regions of Yucatan preserve greater diversity, representing 44 and 40% of the total collections, respectively. There were significant differences in all ear variables; in a late growth cycle, only the grain thickness did not show differences between populations, and in the early growth cycle the grain thickness, width, and length variables were not significant. The PCA explained 80% of the total variation, seven different groups were formed, with greater differentiation in early maize Nal tel, intermediate Xmejen nal and Dzit bacal, contrary to the Tuxpeños late maize. Ten promising populations were identified for selection in each geomorphological region: eight correspond to the southern, two to the eastern, and one to the center of Yucatan state. The main factors to select for sowing corn in the region are: white and yellow maize for yield, the resistance to weevil attack for red maize, and the perception of color and palatability in purple maize. <strong>Implications: </strong>A complete phenotypic characterization in the field is required with a special interest in red-pigmented maize.<strong> Conclusions: </strong>The interest of the milperos in conserving and sowing the different native maize are based on the color of the grain, the benefits and uses that they can obtain from them, which determine the planting area in the milpas of the different races/varieties of maize. Red grain maize is being planted in a lower area in relation to other colors. The southern and eastern geomorphological regions showed a genetic flow between them.</p>

Coffee Berry Borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae): Activity and Infestation in the High Mountain and Blue Mountain Regions of Jamaica.

Jamaica produces coffee marketed as Blue Mountain and high mountain (grown outside the Blue Mountains). Since the discovery of the coffee berry borer (CBB; Hypothenemus hampei) in Jamaica in 1978, chemical control has traditionally been the primary approach used to protect the crop from the pest. However, in the last 20 years, there has been an effort to shift towards more sustainable management strategies. The study was conducted to determine CBB activity (trap catch) and field infestation on coffee farms in the high mountains and Blue Mountains of Jamaica, over a crop cycle. A total of 27,929 and 12,921 CBBs were captured at high mountain and Blue Mountain farms, respectively. Peak CBB activity occurred in April in the high mountain region (365 CBBs/trap/month) and February in the Blue Mountain region (129 CBBs/trap/month). The highest levels of infestation were in November (33%) and October (34%) in the high mountain region and Blue Mountain region, respectively. There was no significant difference in the patterns of CBB activity and infestation between the study locations, and neither were related to the temperature or relative humidity. However, there was a significant relationship with rainfall. These data suggest that the population dynamics of the CBB may involve complex interactions among weather conditions, berry development, and agronomic practices.

Rethinking the potential productivity of crassulacean acid metabolism by integrating metabolic dynamics with shoot architecture, using the example of Agave tequilana.

Terrestrial CAM plants typically occur in hot semiarid regions, yet can show high crop productivity under favorable conditions. To achieve a more mechanistic understanding of CAM plant productivity, a biochemical model of diel metabolism was developed and integrated with 3-D shoot morphology to predict the energetics of light interception and photosynthetic carbon assimilation. Using Agave tequilana as an example, this biochemical model faithfully simulated the four diel phases of CO2 and metabolite dynamics during the CAM rhythm. After capturing the 3-D form over an 8-yr production cycle, a ray-tracing method allowed the prediction of the light microclimate across all photosynthetic surfaces. Integration with the biochemical model thereby enabled the simulation of plant and stand carbon uptake over daily and annual courses. The theoretical maximum energy conversion efficiency of Agave spp. is calculated at 0.045-0.049, up to 7% higher than for C3 photosynthesis. Actual light interception, and biochemical and anatomical limitations, reduced this to 0.0069, or 15.6 Mg ha-1 yr-1 dry mass annualized over an 8-yr cropping cycle, consistent with observation. This is comparable to the productivity of many C3 crops, demonstrating the potential of CAM plants in climates where little else may be grown while indicating strategies that could raise their productivity.

Germplasm Diversification in Citrus Orchards in a Mesothermal Climate in Brazil

The limited scion-rootstock combinations used in sweet orange orchards in Brazil reduce the commercial potential of citrus and lead to greater susceptibility to pests and diseases. Aiming to provide germplasm diversification, the research evaluated the Folha Murcha (FM) and Charmute de Brotas (CB) orange trees grafted onto ‘Rangpur’ lime (RL) and ‘Swingle’ citrumelo (SC) rootstocks. The study was conducted in the southern center of the state of São Paulo, in the subtropical region of southeastern Brazil. The grafted trees were planted in September 2016. The field experiment was conducted over two seasons. The combinations were evaluated based on the duration in days and degree-days of the phenological intervals, growth and yield performance, alternate bearing, fruit ripening, and quality. The trees of the two scion cultivars grafted onto RL had the shortest crop cycle, the earliest fruit ripening, and the largest canopy volume. SC produced fewer alternate bearings with greater production efficiency. The CB/SC combination produced fruits with a better color index, higher total soluble solids content, and a higher technological index. This assessment can be useful in planning orchards for dual-purpose markets, such as table fruit and the juice industry.

A first look at the ability to use genomic prediction for improving the ratooning ability of sugarcane.

The sugarcane ratooning ability (RA) is the most important target trait for breeders seeking to enhance the profitability of sugarcane production by reducing the planting cost. Understanding the genetics governing the RA could help breeders by identifying molecular markers that could be used for genomics-assisted breeding (GAB). A replicated field trial was conducted for three crop cycles (plant cane, first ratoon, and second ratoon) using 432 sugarcane clones and used for conducting genome-wide association and genomic prediction of five sugar and yield component traits of the RA. The RA traits for economic index (EI), stalk population (SP), stalk weight (SW), tonns of cane per hectare (TCH), and tonns of sucrose per hectare (TSH) were estimated from the yield and sugar data. A total of six putative quantitative trait loci and eight nonredundant single-nucleotide polymorphism (SNP) markers were associated with all five tested RA traits and appear to be unique. Seven putative candidate genes were colocated with significant SNPs associated with the five RA traits. The genomic prediction accuracies for those tested traits were moderate and ranged from 0.21 to 0.36. However, the models fitting fixed effects for the most significant associated markers for each respective trait did not give any advantages over the standard models without fixed effects. As a result of this study, more robust markers could be used in the future for clone selection in sugarcane, potentially helping resolve the genetic control of the RA in sugarcane.

Intercropping organic melon and cowpea combined with return of crop residues increases yields and soil fertility

The growth of legumes, reduced tillage and addition of crop residues can be regarded as a good alternative in intercropping systems to increase soil organic matter, soil fertility and biodiversity while enhancing crop production and reducing the use of fertilizers. Despite the potential benefits, there is still a research gap about using the combination of cowpea and melon in intercropping to increase productivity and reduce external inputs. Thus, the aims of this study were to: i) assess if crop yield, crop quality and soil physicochemical properties can be improved by intercropping systems between melon (Cucumis melo L.) and cowpea (Vigna unguiculata (L.) Walp.) with reduced tillage and addition of crop residues, compared with a melon monoculture with intensive tillage and removal of crop residues, all grown under organic management; and ii) evaluated if cowpea grown as intercrop with fertilization reduced by 30% in the diversified plots can partially replace the use of fertilizers with no negative effects on total crop production. In this study we compared over three crop cycles monocrops with three different melon-cowpea intercropping patterns: mixed intercropping, row intercropping 1:1 (melon:cowpea) and row intercropping 2:1 (melon:cowpea). Our results, presented in this study, showed that intercropping systems, regardless of the pattern, kept soil organic C levels, while it significantly decreased in melon monoculture. Intercropping also significantly increased soil total N, available P and exchangeable K (0.13%, 62 mg·kg-1 and 387 mg·kg-1, respectively), compared to the melon monocrop (0.11%, 25 mg·kg-1 and 306 mg·kg-1). Total crop production was significantly higher under diversified systems, with land equivalent ratios > 1. Hence, the introduction of cowpea associated with melon, combined with reduced tillage and the incorporation of crop residues could be considered as a feasible strategy for sustainable agriculture, with environmental gains and economic savings for fertilizers and water.

Environmental Life Cycle Analysis of Açaí (Euterpe oleracea) Powders Obtained via Two Drying Methods

Açaí is a fruit native to Brazil that is found in Colombia, and it is recognized for containing more than 90 compounds with anticancer, anti-inflammatory, and other biological activities. In this study, a cradle-to-gate life cycle analysis (LCA) was conducted for the production of açaí powder, following the methodology outlined in the ISO 14040 standard. The investigation focused on examining the impact of utilizing or not utilizing the residues generated during the pulp extraction step as fertilizers. Four scenarios were analyzed and compared: (i) production of açaí powder via vacuum drying, (ii) via spray drying, and via the same two types of drying but using residues from the pulping operation as fertilizer (Scenarios 3 and 4). It was found that to produce 1 kg of açaí in a crop cycle, 1.17 kg of CO2 eq is produced. The drying stage in Scenarios 1 and 2 generated 8.04 and 7.93 kg of CO2 eq, respectively. Similarly, when solid waste is used as fertilizer, CO2 emissions barely increased for Scenarios 3 and 4, respectively. To the authors’ knowledge, this is the first carbon footprint study of the production of açaí powder whit these scenarios.