Summer Crops Research Articles

Contrasting effects of soil type and use of cover crops on nitrogen and phosphorus leaching in agricultural systems of the Argentinean Pampas

Agricultural systems of the Argentinean Pampas generally use rotations of summer crops under no-tillage and apply fertilization at rates that do not compensate nutrient exports with grain harvest, resulting in negative balances and soil fertility loss. However, the humid climate, long fallow periods and soil factors enhance nitrogen (N) and phosphorus (P) leaching, which has a negative impact on freshwater ecosystems. We propose to evaluate the effect of soil type and replacement of fallow periods with cover crops on drainage and N and P leaching. We used lysimeters containing two Mollisols of contrasting texture and porosity (a Typic Argiudoll and a Typic Hapludoll), and cultivated between 2014 and 2022 with a maize-soybean rotation with (M-CC-S) and without (M-S) cover crops under no tillage.The amount of drainage varied with rainfall (p<0.01), was similar between soils and higher in M-S than in M-CC-S during the intercropping period (148 vs 96 mm, p<0.05). The correlation between daily rainfall and drainage was higher for the Typic Argiudoll (r=0.46 and 0.42, for M-S and M-CC-S, respectively) than for the Typic Hapludoll (0.28 and 0.23 for M-S and M-CC-S, respectively) when considering same-day events, and it decreased for the Typic Argiudoll (r=0.31 and 0.26, for the M-S and M-CC-S, respectively) but not for the Typic Hapludoll (0.28 and 0.21 for the M-S and M-CC-S, respectively) with a 1-day lag between series. The amount of N and P lost through leaching varied with drainage (p<0.01). Cover crops reduced nitrate leaching to a greater extent in the Typic Hapludoll (from 30.4 to 3.3 kg ha−1 period−1) than in the Typic Argiudoll (from 17.6 to 2.0 kg ha−1 period−1) (p<0.05). Soil type modified P leaching in M-S (0.32 and 0.11 kg ha−1 period−1 for the Typic Argiudoll and the Typic Hapludoll, respectively) and M-CC-S had intermediate P leaching (0.17 and 0.16 kg P ha−1 period−1 for the Argiudoll and Hapludoll, respectively) (p<0.05).We conclude that: 1) water flows through different channels in each soil, the rapid flow of the Typic Argiudoll probably occurs through preferential flow channels (macropores) while the slower flow of the Typic Hapludoll is probably associated to matrix porosity, 2) P leaching is related to soil type (Typic Argiudoll > Typic Hapludoll) and drainage reduction by cover crops off-sets P leaching through macropores in the Typic Argiudoll, and 3) cover crops reduce N leaching, due to drainage reduction and N retention in cover crop biomass.

Diversification of wheat-maize double cropping with legume intercrops improves nitrogen-use efficiency: Evidence at crop and cropping system levels

Context or problemThe sustainability of traditional maize-wheat (M-W) double cropping in the North China Plain (NCP) is threatened by excessive nitrogen (N) input and surplus. Meanwhile, there is strong market demand of more protein and oil crops, such as soybean or peanut. Incorporation of legumes into M-W via intercropping with maize is emerging in the NCP to foster China’s self-sufficiency for edible oils and proteins. Objective or research questionIt is unknown how such a change in cropping system affects the required annual fertilizer N input, and the resulting N-use efficiency (NUE) and N surplus (Ns). MethodsWe conducted a four-year field experiment involving four N fertilizer rates and rotations of winter wheat with six different summer crops: maize (conventional and density-increased), peanut (P), soybean (S), and intercrops of density-increased maize and peanut or soybean (MP, MS). The “three-quadrant diagram” and NUE proposed by the EU Nitrogen Expert Panel (EUNEP) were used to assess NUE at crop and cropping system level, respectively. ResultsLand equivalent ratios of N uptake in intercrops averaged 1.02–1.07 while N fertilizer equivalent ratios averaged 1.15–1.20, indicating more efficient N uptake and more yield per unit fertilizer than sole crops. Intercropped maize exhibited greater N acquisition efficiency than sole maize. Inclusion of intercrops lowered required annual N inputs and Ns and increased the apparent recovery efficiency (RE) of applied N and EUNEP-NUE. Soybean was a more productive and N-use efficient companion species for maize than peanut. Increasing N decreased RE and EUNEP-NUE while elevated Ns of all rotation systems. N productivity responses of each rotation system to increasing N followed a “linear-plateau” model. Compared to M-W with an optimal 240–360 kg N/ha, MS-W with 210–320 kg N/ha saved 11.1–12.5% fertilizer, increased N uptake by 12.4–16.0%, augmented RE from 36.0–37.0% to 47.8%, increased EUNEP-NUE from 0.50 to 0.67 kg/kg (within the target of 0.50–0.90 kg/kg), lowered Ns by 38.8–39.2%, and reduced N emission by 48.6–49.3%. ConclusionsTherefore, here we show for the first time, using multiple N performance indicators, that MS-W with moderate N provides diversified products, higher N productivity, NUE and lower N loss than M-W, thus being a suitable option for sustainable intensification of agricultural production. Implications or significanceSuch a diversified rotation approach with legume intercropping aligns with the principles of agricultural green development and has a global relevance for countries with sequential double cropping or rotation systems.

Investigation the implications of climate change on crop water requirements in Western Nile Delta, Egypt

Investigation the implications of climate change on crop water requirements in Western Nile Delta, Egypt

How to account for irrigation withdrawals in a watershed model

Abstract. In agricultural areas, the downstream flow can be highly influenced by human activities during low-flow periods, especially during dam releases and irrigation withdrawals. Irrigation is indeed the major use of freshwater in the world. This study aims at precisely taking these factors into account in a watershed model. The Soil and Water Assessment Tool (SWAT+) agro-hydrological model was chosen for its capacity to model crop dynamics and management. Two different crop models were compared in terms of their ability to estimate water needs and actual irrigation. The first crop model is based on air temperature as the main determining factor for growth, whereas the second relies on high-resolution data from the Sentinel-2 satellite to monitor plant growth. Both are applied at the plot scale in a watershed of 800 km2 that is characterized by irrigation withdrawals. Results show that including remote sensing data leads to more realistic modeled emergence dates for summer crops. However, both approaches have proven to be able to reproduce the evolution of daily irrigation withdrawals throughout the year. As a result, both approaches allowed us to simulate the downstream flow with a good daily accuracy, especially during low-flow periods.

Agricultural land management extends the duration of the impacts of extreme climate events on vegetation in double–cropping systems in the Yangtze–Huai plain China

Extreme climate events can have severe impacts on both vegetation and the carbon cycle. However, whether land management exacerbates or mitigates the effects of extreme climate events on vegetation remains unknown. We investigated the case of an extreme precipitation event that occurred in a region dominated by double–cropping (DC) systems located in the Yangtze–Huai plain in China. Waterlogging disasters were triggered by an extreme precipitation event in October 2016, which severely affected the sowing and seedling emergence of winter crops (mainly winter wheat). The lack of sowing and low seedling emergence rate subsequently led to months of low growth, as evidenced by negative enhanced vegetation index (EVI) anomalies, especially from March to May 2017. Local agricultural meteorological monthly reports, government announcements, and winter wheat data based on statistics and remote sensing confirmed the reduced yields. The influence on vegetation ended in June 2017, when summer crops were planted. Our results demonstrate that, in such a DC system, when extreme events occur during the key sowing period, the impacts will continue through the entire crop growth period, until the next sowing. More generally, agricultural land management could extend the duration and magnitude of the impacts of extreme climate events on vegetation.

Cover crop diversity for sustainable agriculture: Insights from the Cerrado biome

AbstractBrazil is one of the largest soybean producer of the world and the Cerrado biome has played a pivotal role in this expansion. Because of the economic and agronomic challenges associated with the maize production as a second summer crop in this region, cover crops are gaining popularity as a strategy to diversify the agricultural system while enhancing soil health. This study assessed the benefits of single species of cover crops and a mix of cover crop species in between harvest seasons to the soybean grain yield and nematode suppression. The study was carried out for 3 years in two locations within the Cerrado biome. We evaluated six cover crop treatments after soybean cultivation: (1) Mix of cover crops (Pennisetum glaucum, Crotalaria spectabilis and Urochloa ruziziensis), (2) P. glaucum (Pearl millet), (3) C. spectabilis, (4) U. ruziziensis (Congo grass) (5) Urochloa brizantha cv. Marandu (Marandu palisadegrass) and (6) U. brizantha BRS Paiaguás (Paiaguás palisadegrass). Pennisetum glaucum and U. brizantha cv. Marandu produced highest amounts of biomass on a 3‐year average. In one site, P. glaucum produced more biomass than other cover crops by 210%. Tropical grasses (U. ruziziensis, Marandu and Paiaguás), along with the cover crop mixture, exhibited intermediate biomass levels in the site with higher P. glaucum biomass production and did not differ from P. glaucum in the other site. Cover crops varied nutrient uptake depending on the species. Decomposition rates varied among cover crops as expected, with C. spectabilis decomposing rapidly and releasing substantial amounts nutrients, particularly nitrogen. In contrast, the cover crop mixture had a slower decomposition. The choice of cover crop significantly influenced soybean population and yield, with some variability across years and locations. The cover crop mixture consistently supported higher soybean populations and yields, highlighting its potential for enhancing soybean production, nutrient cycling and nematode suppression. It effectively reduced nematode abundance in soybean roots, highlighting its role in nematode management. Our findings emphasize the robustness and versatility of cover crop mixtures in mitigating weather variability across years and sites. They consistently performed well in terms of biomass production, nutrient uptake, soybean yields and nematode control. This study highlights the vital role of cover crops in the Cerrado ecosystem, enhancing soil health, crop productivity and environmental sustainability. The choice of cover crop species and mixtures offers a valuable tool for farmers seeking resilient and sustainable agricultural practices amid changing environmental conditions.

Potato agriculture research Station Batakundi, naran, a hot spot for cyst nematode (Globodera spp.) of potato in Pakistan

In Pakistan, potato summer crop in being cultivated in different agro-ecologies of Khyberpukhtun Khwa and in valleys of Gilgit Baltistan provinces. To understand the current biotic stresses scenario in the potato germplasm developed by National Institute of Genomics and Advanced Biotechnology (NIGAB) was cultivated in 2022-23. The valleys comprised on Sharan Forest Kaghan, Potato Agriculture Research Station, Batakundi Naran of KPK and Babusar valley as well as Mountain Agriculture Research Station, Chillas of Gilgit Baltistan were systematically surveyed. The soil samples were analyzed in for the cyst nematode (Globodera spp.) in potato fields as an invasive and quarantine regulated pest. Severe infestation of PCN was observed in PARS, Batakundi Naran. However, there were no any cyst was found in the rest of ecologies surveyed. The population dynamics of PCN was estimated ranges from 113-150 cysts in 100grams of soil samples. The center is being used as potato monoculture and crop breeding. The egg count estimates ranges from 270-320 eggs/cyst. There are some cysts showed the suppressive soil state as the eggs were infested with endophytes or rhizospheric microorganisms (bacteria or fungi). The cysts were morphologically characterized and identified in Crop Diseases Research Institute (CDRI) and National Nematological Research Center Pakistan.

Grain yield and quality characteristics of some grass pea (Lathyrus sativus L.) genotypes grown as summer and winter crop under ecological conditions of Yozgat

Amaç: Türkiye’de uzun yıllardır kaliteli kaba yem açığı bulunmaktadır. Bu durum hayvanların kalitesinde ve verimlerinde düşüşler meydana getirmektedir. Diğer taraftan kurak ve yarı kurak iklim kuşağında yer alan Türkiye iklim değişikliğinden en fazla etkilenmesi beklenen ülkeler arasında yer almaktadır. Yem bitkileri açığı ve iklim koşullarında beklenen olumsuzluklar koşullarına uygun bitkilerin yetiştirilmesini zorunlu hale getirmektedir. Baklagiller familyasında yer alan mürdümük (Lathyrus sativus L.) hayvan besleme açısından oldukça önemli bir yere sahip olup, kuraklığa toleransı yüksektir ve çok farklı topraklarda rahatlıkla gelişme gösterebilmektedir.&#x0D; Materyal ve Metot: Bu çalışmada; Yozgat ekolojik koşullarında kışlık ve yazlık olarak ekilen farklı mürdümük genotiplerinin (Gap Mavisi, Eren, İptaş, Karadağ, 1603, 2006, 2401, 4301, 4403, 5001, 6408, 6410 ve S3) tane verimi ve kalitesinin belirlenmesi amaçlanmıştır. Çalışma 2019-2020 vejetasyon döneminde ve Bölünmüş Parseller Deneme Desenine göre 3 tekerrürlü olarak kurulmuştur.&#x0D; Araştırma Bulguları: Bitkilerin tohumlarında, tane verimi, ham protein oranı, ODAP (N-oxalyl-L-alpha,beta-diaminopropionic acid), toplam fenolik, toplam flavonoid, radikal kovucu aktivite (DPPH) ve kondanse tanen içerikleri belirlenmiştir.&#x0D; Sonuç: Çalışmadan elde edilen verilere göre, yazlık ekimlerin kışlık ekimlere göre daha üstün olduğu, hayvan besleme ve verimlik açısından ise bazı popülasyonların çeşitlerden daha iyi sonuçlar sergilediği tespit edilmiştir.

Crop rotation for management of plant‐parasitic nematodes in forage corn production

AbstractCorn (Zea mays L.) is an important silage source for dairy cattle production in the southeastern United States. Silage corn is often grown continuously, which frequently results in severe pressure from plant‐parasitic nematodes such as sting nematode (Belonolaimus longicaudatus). Crop rotation is one of the few nematode management options available in forage production. The research objective was to assess summer‐planted rotation crops, preceding spring silage corn, for management of plant‐parasitic nematodes. Rotation crops included field corn, pearl millet [Cenchrus americanus (L.) Morrone]—with or without fertilizer—, sorghum‐sudangrass [Sorghum bicolor (L.) Moench × Sorghum sudanense Piper], and sunn hemp (Crotalaria juncea L.), which was either incorporated into soil or harvested. Rotation crops were assessed in a 3‐year field study in central Florida. Sunn hemp treatments significantly reduced sting nematode soil abundances relative to corn by 84%, 90%, and 84% before spring corn planting in 2019–2020 and 2020–2021 and at rotation crop termination in 2021–2022, respectively. Abundances of other plant‐parasitic nematodes were not consistently influenced by rotation. Biomass of winter rye (Secale cereale L.)—a bridge cover crop between summer and spring crops—was consistently increased following sunn hemp with significant increases of 87%, 106%, and 186% relative to following corn in 2019–2020, 2020–2021, and 2021–2022, respectively. Similarly, sunn hemp significantly increased spring corn yield by 70% and 136% relative to double‐cropped corn in 2020–2021 and 2021–2022, respectively. Overall, rotation with sunn hemp improved plant‐parasitic nematode management in forage corn production relative to rotations with only gramineous crops.

Impact of Sclerotinia sclerotiorum Infection on Lettuce (Lactuca sativa L.) Survival and Phenolics Content-A Case Study in a Horticulture Farm in Poland.

Sclerotinia sclerotiorum is a cause of a prevalent and destructive disease that attacks many horticultural food crops, such as lettuce. This soil-borne necrotrophic fungal pathogen causes significant economic losses in worldwide lettuce production annually. Furthermore, current methods utilized for management and combatting the disease, such as biocontrol, are insufficient. In this study, three cultivars of lettuce (one Crispy and two Leafy cultivars of red and green lettuce) were grown in central Poland (Lodz Voivodeship), a widely known Polish horticultural region. In the summer and early autumn, lettuce cultivars were grown in control and S. sclerotiorum-infected fields. The lettuce cultivars (Templin, Lollo Rossa, and Lollo Bionda) differed phenotypically and in terms of the survival of the fungal infection. The Crispy iceberg Templin was the most susceptible to S. sclerotiorum infection compared to the other cultivars during both vegetation seasons. The total content of phenolic compounds, flavonoids, and anthocyanins varied among cultivars and fluctuated during infection. Moreover, phenolic content was affected by vegetation season with alterable environmental factors such as air temperature, humidity, soil temperature, and pH. The most increased levels of phenolics, both flavonoids and anthocyanins in infected plants, were observed in the Leafy red Lollo Rossa cultivar in both crops. However, the highest survival/resistance to the fungus was noticed for Lollo Rossa in the summer crop and Lollo Bionda in the autumn crop.

Chlorophyll Fluorescence Parameter as a Tool in Selecting Heat-tolerant Summer-flowering Chrysanthemum (Dendranthema ×grandiflorum)

Chrysanthemum ‘Bai Tian Xing’, ‘Huang Ching Chin’, ‘Pink Pearl’, and ‘NCHU-001’ plants were preheated at 35 °C for 24 hours to induce heat tolerance. The recently fully expanded leaves were detached, kept in a moist Ziploc bag, and then subjected to 35, 40, 45, 47.5, 50, 52.5, 55, 60, or 65 °C for 20 minutes. After dark-acclimatized at room temperature for 30 minutes, leaves were measured for Fv/Fm value with a chlorophyll fluorescence parameter. Results showed that ‘Bai Tian Xing’ had the highest critical (Tcrit) and midpoint temperature (Tmid). Mean Tcrit and Tmid were shown to be 47 and 50 °C, respectively, and Tmid gave greater distinguishment of Fv/Fm value among cultivars. Plants of four cultivars were acclimatized at 15 to 40 °C for 3 days and 35 °C being the most effective temperature to induce a heat-tolerant response in chrysanthemum. Required inducing time to reach a stable leaf Fv/Fm value ranged from 4.6 to 11.1 hours among cultivars. All cultivars had similar required time to reach visible bud between summer and autumn crops (except NCHU-001), but all had delayed flowering in the summer crop. There is a negative linear relationship between flowering heat delay and leaf Fv/Fm value (R2 = 0.93). Progenies from reciprocal crossing of ‘Bai Tian Xing’ × ‘NCHU-001’ and ‘Huang Ching Chin’ × ‘Pink Pearl’ were also subjected to treatments for Fv/Fm measurements and observed for time to flowering in the summer crop. All combinations showed negative linear relationship between time to flowering and leaf Fv/Fm value (R2 = 0.70–0.87). Two plants, 109-W001Y and 109-W003Pi, showed early flowering habit and good flower performance under heat conditions were selected. All four cultivars and the two selected lines were measured for photosynthetic parameters under day/night temperatures of 35/30 or 25/20 °C in growth chambers. All cultivars and lines showed decreased net photosynthetic rate and dark respiration rate under 35/30 °C when compared with 25/20 °C. Relatively higher net photosynthetic rate and lower dark respiration rate in ‘Bai Tian Xing’, ‘109-W001Y’, and ‘109-W003Pi’ under 35/30 °C, when compared with the other three cultivars, might have contributed to better flowering performance in the summer.

Phenology and radial growth of poplars in wide alley agroforestry systems and the effect on yield of annual intercrops in the first four years of tree age

Silvoarable agroforestry systems have the potential to combat the negative effects of climate change while also enhancing productivity per unit land. Although the growth rate of large-spaced trees remains poorly investigated and the yield of annual intercrops uncertain, silvoarable agroforestry systems with poplar are receiving an ever-growing interest. This study assessed the growth of the new HES (High Environmental Sustainability) poplar clone, Moncalvo, arranged in 40-m spaced parallel alleys with a density of 35 trees ha−1 (SA, silvoarable). Their growth was compared to those cultivated in a specialized poplar plantation (C, control) with 277 trees ha−1, and the agronomic impact on wheat and soybean as intercrops was explored. Measurements took place between 2018 and 2021 during the first 4 years, which represents the midpoint of the expected poplar rotation. Here it was demonstrated that at the end of the investigated period, diameter at breast height was significantly greater (23.8 vs. 20.5 cm, +16%) and the plant height lower (14.3 vs. 15.5 m, −8%) in poplar grown in SA as compared to those in C, likely due to reduced intraspecific competition for environmental resources. In SA, seasonal tree phenology was delayed by approximately two weeks in spring, possibly due to the high sensitivity of poplar to low soil water content and cooler night air temperatures in springtime. The grain yield of wheat was not impaired by tree shading but instead occasionally improved when neighboring the poplar alley (e.g., year 2021: +28% at 12 m from the tree row vs. full sun conditions), while soybean yield was generally reduced (maximum −38% at 6 m from the tree row). This study innovatively studied the growth response of HES poplar clones in silvoarable systems by providing valuable insights into the growth dynamics of trees grown in combination with field crops. It is concluded that poplars in wide spaced alleys of silvoarable systems in temperate climates grow faster than poplars in plantations of high population density due to enhanced access to resources, while future investigations will allow for the identification of clone-specific rotation durations. In the arable tree interrow, winter crops more readily benefit from such agroforestry system than summer crops due to reduced cycle overlap and light competition with the tree canopy.

Soil microbial properties are improved by the adoption of soil management and conservation practices in no-tillage system

ABSTRACT No-tillage system (NTS) plays a prominent role in conservation agriculture, however, its benefits can be further improved by adopting complementary soil management and conservation practices, such as using autumnal cover crops, contour seeding, and terraces. This study aimed to evaluate how soil biological activity responds to soil management and conservation systems. The treatments consisted of three macroplots with an area of 11.000 m 2 each, as follows: a) Non-Terraced catchment (NTC), cultivated in NTS similar to most farmers of the region, in which the agricultural operations are carried out in the direction of the slope and without terraces used; b) Best Management Practices (BMPs) were adopted in NTS with additional autumnal cultivation of cover crops, and also the direction of machine traffic was transverse to the slope direction; and c) Terraced catchment (TC), cultivated in NTS was associated to mechanical practices to erosion control, using wide base terrace on level. Soil microbial properties sampled in the 0.00-0.10 m layer were evaluated during 2019, 2020, and 2021, all shortly after the summer crop harvest. Natural inoculum potential of arbuscular mycorrhizal fungi (AMF), respirometry, metabolic coefficient, acid phosphatase activity, and organic carbon and nitrogen in the microbial biomass were assessed. Averages of each microbiological properties were compared through the confidence intervals (p&lt;0.05). The results showed a greater potential for AMF inoculum in BMPs and TC systems. The NTC showed the highest values of respirometry and metabolic quotient, releasing 31.7 and 27.3 % more CO 2 compared to BMPs and TC, respectively. The BMPs and TC were able to retain 13.8 and 16.5 % more carbon in the microbial biomass and 8.0 and 8.8 % more nitrogen in the biomass than NTC, respectively. Adopting soil management and conservation practices such as autumn cover crops, level seeding, and wide base terrace on level improved the soil microbial properties, with an increase in AMF inoculum potential, higher levels of acid phosphatase activity, and increment of carbon and nitrogen in microbial biomass.

Optimized planting structures maintain system yield and economic benefits with less nitrogen footprint

ContextsThe Huang-Huai-Hai Plain in China relies heavily on the winter wheat-summer maize rotation for grain production. However, this cropping system faces challenges regarding its sustainability due to significant environmental costs. ObjectivesThis study aims to evaluate the nitrogen footprint of different cropping systems, compare their economic benefits, and identify alternative summer crops that can optimize system yield, economic advantages, and environmental impact. MethodsA three-year field experiment was conducted to compare the economic and environmental impacts of three cropping systems: winter wheat-summer maize (W-M), winter wheat-summer soybean (W-S), and winter wheat-sweet potato (W-SP). The experiment involved assessing yield, inputs, and outputs, and conducting a comprehensive nitrogen footprint analysis for each system. ResultsOver the three experimental years, the W-S system showed the highest yield improvement for winter wheat. The W-SP system had the highest annual maize equivalent yield and total income but incurred the highest total annual cost compared to the other two systems. However, the W-SP system demonstrated the highest annual average economic profit performance, nearly double that of the other two systems. The nitrogen footprint analysis revealed that both the W-S and W-SP systems reduced reactive nitrogen emissions compared to the W-M system. Notably, the W-S system managed to reduce the nitrogen footprint by 34%. The average nitrogen footprint emissions scores for W-M, W-S, and W-SP systems were 2.1, 2.3, and 3.5, respectively. ConclusionsAmong the three systems, the W-SP system achieved the highest economic benefits but also had the greatest negative environmental impact. The W-S system demonstrated a significant reduction in reactive nitrogen loss while maintaining productivity, indicating its potential for mitigating negative environmental impacts. SignificanceOur three-year field study highlights the advantages of the W-S system in reducing the nitrogen footprint and its potential contribution to sustainable agricultural development in the Huang-Huai-Hai Plain.

Detection rates of pesticide residues in Saudi Arabian produce as influenced by season

Pesticide residues and persistent organic pollutants (POPs) are known hazardous chemicals that exhibits bioaccumulation in organisms and the ecosystem in general. There is limited evidence on the levels of these contaminants among common Saudi crops grown as well as the effects of season on their levels. Hence, the present investigated the levels of pesticide residues in major fruit and vegetable crops collected during the winter and summer seasons in Saudi Arabia (SA). A total of 392 samples taken from 28 locally produced vegetables and fruits were purchased from local markets in Riyadh, SA during peak summer (N = 263) (June-August 2022) and peak winter (N = 129) (December-February 2022). Food samples were extracted and cleaned up using the modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) technique. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC–MS/MS) instruments were used to determine pesticide residues. Crops that had the highest percentage exceeding the maximum residue limit (MRL) include pepper (7.9 %) as well as apricot, fig and pomegranates (3.1 %). Cypermethrin was the most prevalent pesticide residue in both winter and summer samples with detection rates of 13.2 % and 14.1 % respectively (p = 0.33). Thiamethoxam detection rates was significantly higher in winter (7.8 %) than summer (3.0 %) (p = 0.04). There is a high detection rate of pesticide residues in SA independent of season, with cypermethrin being the most common. Thiamethoxam is more commonly detected in winter than summer crops. The study should be extended to include other potential sources of pesticide residues such as fishes grown in aqua farms and other poultry products.

Influence of Sowing Time on Plant Growth and Production for some Varieties of Chard, in Western Part of Romania

In Romania, chard is a less cultivated species, being present in some areas of Transylvania, on small areas. This research followed the results regarding chard growth and quantitative and qualitative production, obtained by growing plants in the specific conditions Western Romania. Experiment was bifactorial (5x2 type), with ten experimental variants. Comparative crops were carried out in summer and autumn, respectively, with differences in chard plants development (diameter of leaf rosette, length of leaves and petiole) and in the production achieved by varieties used in this research. For some experimental variants, the yields obtained were over 40 t/ha, being comparable to those obtained and mentioned in literature. Chard leaves content in dry matter as well as vitamin C was also monitored, results being comparable to those obtained in other growing conditions in Europe. Sowing time influenced chard total production, in summer crop being higher compared to autumn one. Also, dry matter and vitamin C content was influenced, crops harvested in autumn registered higher results regarding these traits.

Fitness and cold tolerance of Spodoptera frugiperda fed on corn and two winter crops

AbstractFall armyworm (FAW) Spodoptera frugiperda is a major migratory and polyphagous pest. Overwintering, migrating and colonizing characters of FAW are closely related to vegetation and host adaptation. In this study, we investigated oviposition preference, feeding preference of FAW, as well as fitness, cold tolerance of FAW larvae fed on spring and summer crop (corn) and two winter crops (cabbage, Brassica campestris and rape, B. napus). The results showed that FAW could complete their life cycle by feeding on cabbage and rape, although fitness was not as good as corn. FAW fed on cabbage had higher survival, female pupal mass and host suitability index than rape while larvae preferred to feed on rape leaves and females preferred to lay eggs on rape plants. In addition, FAW larvae fed on cabbage had the shortest recovery time from chill coma compared to corn and rape, indicating that cold tolerance of FAW larvae was improved by feeding on cabbage. Consequently, cabbage could be an ideal host for FAW which needed to survive and reproduce in winter. These results improve our understanding of host selection and adaption of FAW, as well as lay a foundation for predicting winter breeding areas of FAW.

Winter-time cover crop identification: A remote sensing-based methodological framework for new and rapid data generation

Accurately identifying and systematically mapping winter-time cover crops and their phenological characteristics offer significant benefits to agricultural producers and policymakers, as cover crops are one of several potential solutions to climate change mitigation. We present a methodological framework for identifying and mapping the presence of winter-time cover crops at the field level and aggregated to county scales from 2013 to 2019 by using the Google Earth Engine (GEE), a random forest classifier with time series data from Landsat 8, and yearly cover crop training data from the United States Department of Agriculture (USDA)-Natural Resources Conservation Service (NRCS). The methodology was tested with data from the Mississippi Alluvial Plain (MAP) region. Despite the inter-annual agronomic and climatic variations across space, results demonstrated an overall mean classification accuracy of 97.7%, with a kappa coefficient of 0.94. Results also revealed a 34% increase in model-predicted cover crop adoption in the study region from 2013 to 2019. Based on GEE, this study created, for the first time, a 30-m spatial and temporal resolution binary annual datasets and then aggregated them at the county level within the MAP study region. This multi-year novel dataset may improve our ability to anticipate and quantify the impact of summer crop production gains owing to cover crop adoption for extended periods and evaluate the adoption of cover crops on local soil ecosystems, biogeochemical cycles, and services. The methodology developed and tested broadly applies to other regions where cover crops have been promoted for climate-change mitigation and improving soil health for long-term sustainability. Agricultural producers, policymakers, and cost-share providers may use this information to develop agricultural conservation methods and land-use policies that minimize soil erosion and help mitigate climate change effects in the long run.

Herbicide Program to Control Parthenium hysterophorus in Grain Sorghum in an Arid Environment

Parthenium weed (Parthenium hysterophorus L.) is an emerging production constraint in many summer crops including sorghum (Sorghum bicolor L. Moench), but limited control options are available. In this field study, the efficacy of sole and sequential applications of a pre-emergence (pendimethalin) and a post-emergence (bromoxynil) herbicide was evaluated for parthenium weed control in grain sorghum over two years. Pendimethalin or bromoxynil alone could only provide 54% and 63% control, whereas their sequential application provided 86% control of parthenium weed over the weedy treatment. The sorghum plants in pendimethalin followed by bromoxynil treatment had the highest leaf fresh weight per plant, plant dry biomass, plant height, and the number of heads among the herbicide treatments. Sorghum fresh forage yield, dry fodder yield, 1000-grain weight, and grain yield were highest in the weed-free treatment followed by the pendimethalin followed by (fb) bromoxynil treatment. Overall, the herbicide treatment performance was in an order of pendimethalin fb bromoxynil &gt; bromoxynil &gt; pendimethalin for weed control and sorghum yield improvement. These results suggest that pendimethalin followed by bromoxynil may provide acceptable control (&gt;85%) of parthenium weed and may improve sorghum grain yield (up to 23%).

Damage Assessment of Melanagromyza sojae (Diptera: Agromyzidae) on Soybean in Brazil

Soybean stem fly, Melanagromyza sojae Zehntner (Diptera: Agromyzidae), is an important soybean (Glycine max) pest in Eastern Asia that has recently colonized South America. The region colonized by M. sojae includes Brazil and several other major soybean growing countries. Management strategies for this pest remain largely undeveloped due to lack of information regarding its potential to injury soybeans. The objective of this study was to quantify soybean yield reduction caused by M. sojae injury. One experiment was carried out during two summer crop seasons (2020 and 2021) at Santa Maria, RS state, Brazil. Soybean was planted during late-season to ensure that high pressure of M. sojae adults were present in the fields. The number of seeds, 1,000-seed weight, seed yield and number of pods were quantified for the lower, middle and upper canopy, and plant height was compared to the amount of stem injured to determine percentage of injured stem. Each 1% of injured stem in the lower, middle and upper canopy segments significantly reduced the number of seeds per plant, 1,000-seed weight, and yield. Across all canopy segments, yield reduction reached 0.9 g per plant for every 1% of injured stem. Treatments where insecticide applications started during the vegetative phase presented the lowest damage by M. sojae. These data suggest that M. sojae is an economically important herbivore of soybeans under Brazilian growing conditions and highlight the need to develop efficient and sustainable management strategies for this pest.