Summer Corn Research Articles

Achieve simultaneous increase in straw resources efficiency and nitrogen efficiency under crop yield stabilization – A case study of NCP in China for up to 8 years

The experiment is to explore the efficient and comprehensive utilization of maize straw resources to achieve the sustainability of the soil fertility under double cropping of winter wheat and summer maize. Summer maize hybrid Denghai 605 (DH605) and winter wheat variety Tainong 18 (TN18) were used as experimental materials. Based on all winter wheat straw returned to the field, the treatment of all summer maize straw (SR) and half of summer maize straw (1/2SR) and summer maize straw not returned to the field (CK) 3 experimental treatments were tested for 8 consecutive years. Under the condition of normal nitrogen application of 210 kg ha −1 , two split areas were set to reduce the amount of nitrogen fertilizer by 15% and 30% (SR-15%、SR-30%、1/2SR-15%、1/2SR-30%、CK-15%、CK-30%) at the beginning of the 2016 wheat season. In the first two years of reduced nitrogen application, the yields of SR and 1/2SR treatments were significantly higher than that of CK under the same nitrogen application conditions, while the yields of SR, 1/2SR, SR-15%, and 1/2SR-15% were not significantly different. In the third year of the process of reducing nitrogen fertilizer, compared with SR, 1/2SR, and SR-15% treatments, the yield of 1/2SR-15% were significantly reduced by 9% under winter wheat season. During winter wheat and summer maize season, the nitrogen use efficiency, and nitrogen absorption efficiency of SR and 1/2SR were significantly increased compared with CK treatment under the same nitrogen rate, of which SR-15% treatment was not significantly different from SR and 1/2SR. The pre-anthesis nitrogen transfer rate and nitrogen harvest index of summer maize treated with SR, 1/2SR, SR-15% and 1/2SR-15% were also significantly increased, compared with CK and CK-15% treatments. The win-win situation of ecological and crop yield can be achieved by return half of the straw to the field or reducing the nitrogen fertilizer application by 15% under the condition of straw returned to the field. • Returning the full amount of summer corn to the field can stably replace 15% of the nitrogen fertilizer application. • The yield stability and NUE of SR-15% treatment are not significantly different between with SR and 1/2 SR treatments. • The 1/2SR treatment can achieve a synergistic increase in crop yield and nitrogen utilization under NCP in China.

A Novel Prediction and Planning Model for the Benefit of Irrigation Water Allocation Based on Deep Learning and Uncertain Programming

Due to population growth and human activities, water shortages have become an increasingly serious concern in the North China Plain, which has become the world’s largest underground water funnel. Because the yield per unit area, planting area of crops, and effective precipitation in the region are uncertain, it is not easy to plan the amount of irrigation water for crops. In order to improve the applicability of the uncertainty programming model, a hybrid LSTM-CPP-FPP-IPP model (long short-term memory, chance-constrained programming, fuzzy possibility programming, interval parameter programming) was developed to plan the irrigation water allocation of irrigation system under uncertainty. The LSTM (long short-term memory) model was used to predict crop yield per unit area, and CPP-FPP-IPP programming (chance-constrained programming, fuzzy possibility programming, interval parameter programming) was used to plan the crop area and the effective precipitation under uncertainty. The hybrid model was used for the crop production profit of winter wheat and summer corn in five cities in the North China Plain. The average absolute error between the model prediction value and the actual value of the yield per unit area of winter wheat and summer maize in four cities in 2020 was controlled within the range of 14.02 to 696.66 kg/hectare. It shows that the model can more accurately predict the yield per unit area of crops. The planning model for the benefit of irrigation water allocation generated three scenarios of rainfall level and four planting intentions, and compared the planned scenarios with the actual production benefits of the two crops in 2020. In a dry year, the possibility of planting areas for winter wheat and summer corn is optimized. Compared with the traditional deterministic planning method, the model takes into account the uncertain parameters, which helps decision makers seek better solutions under uncertain conditions.

Dynamics of Land and Water Resources and Utilization of Cultivated Land in the Yellow River Beach Area of China

Image analysis of the Yellow River beach area since 1987 provided land use and water body patterns to support effective agricultural and environmental management. Landsat and Sentinel-2A/B images, and data from the Third National Land Survey, were used to examine the water body and land use patterns. The continuous beach land since 1987 was calculated from annual vegetation and water body indexes while that of cultivated land was extracted from the Third National Land Survey. Object-Oriented Feature Extraction was used to extract staple crops. The results showed that 58.26% of the beach area was cultivated land. Continuous beach land covered an area of 1630.98 km2 and was consisted of scattered patches that were unevenly distributed between the north and south banks of the Yellow River. The staple crop types in the beach area, winter wheat and summer corn accounted for 72.37% and 68.03% of the total cultivated land. Affected by the strategy on the Yellow River basin in China, as the ecological space and protection continue to increase, this study provides basic scientific references for the correct use of cultivated land resources and protection of the balance of soil and water resources dynamic utilization and balance of cultivated land protection and ecological protection.

Cover crop effects on μCT‐measured geometrical pore characteristics

AbstractCover crops (CC) could improve soil physical, chemical, and biological properties; however, the micrometer scale quantification of geometric pore characteristics in CC soil is limited in the literature. The objective of this study was to differentiate geometrical pore characteristics between CC and no CC (NCC) by computed tomography (CT). The study design consisted of winter CC and summer corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation with no‐till management. The sample cores were collected after 7 yr of mixed species CC establishment. Six 0‐to‐65‐mm‐long soil cores (28‐mm diam.) were imaged at 29‐μm resolution, and three‐dimensional volumes were analyzed using Fiji‐ImageJ2 software. Slice thickness was 29 μm, and the minimum achievable voxel size was 90 nm. Images within the top and bottom 7.25 mm were removed, and two depths within a core were analyzed for soil pore parameters. The total pore volume was significantly greater (P < .05) in CC compared with NCC, with 8.4 and 2.5 times greater values in CC at 7.25–27.25 and 37.25–57.25 mm, respectively. The total (individual + branched) and the individual pore count were significantly greater (P < .05) in CC compared with NCC for both depths. The porosity of CC soil at 7.25‐to‐27.25‐mm depth was 10 times greater than that of NCC. The branched pore count was not significantly different between two treatments. Overall, the micrometer scale determination of geometrical pore network characteristics showed added benefits of CC use compared with NCC; thus, the use of CC can be beneficial in improving soil pore networks.

Corn and Soybean Productivity in Succession to Family Coverage Plants Poaceae and Fabaceae

The use of soil cover plants has varied effects on crops grown in succession, depending on the cover plant used. The objective of this study was to evaluate the effect of soil cover plants from the Poaceae and Fabaceae families grown in the autumn and winter on yields of corn and soybean grown in succession. The experiment was carried out for two years and the experimental design used was randomized block design, with six replications. Both in the first year and the second, the plots consisted of the cultivation of corn or soybeans on the different biomasses of four cover crops cultivated in autumn and winter intercropped with corn. The cover crops were two Poaceae plants (black oats and brachiaria) and two Fabaceae plants (forage pea and white lupine). The production and productivity parameters of summer corn and soybean commercial crops were evaluated Cover plants of the Poaceae (black oat and brachiaria) and Fabacea (pea and white lupine) families intercropped with corn grown in autumn-winter did not affect their yield components and yield; as well as the productivity of soybeans in succession. According to the results of this work, the cultivation of black oat, brachiaria, forage pea and lupine increases the number of species that the farmer can cultivate intercropped with corn, favoring the crop rotation system in no-till.

Effects of brief exposure to high temperatures on the survival and fecundity of Athetis lepigone (Lepidoptera: Noctuidae).

In Huang-Huai-Hai Summer Corn Region of China, brief periods of high summer temperatures have been reported with increasing frequency in recent years. Athetis lepigone is a cosmopolitan insect which causes severe damage on summer corn seedlings. To understand how high summer temperatures may affect the population dynamics of A. lepigone, we exposed different developmental stages (1, 2 and 4-day old eggs; 1, 6, 12 and 18-day old larvae; 1, 3 and 6-day old pupae; and 1 and 2-day old female and male adults) to 41°C for periods of various length (0.5, 1, 2, 4 and 6h): The rearing temperature (constant 26°C) was used as control. After heat treatment, all individuals were transferred to a 26°C climate chamber for further development. The effects on immediate survival, maturation success to adulthood, and female fecundity were studied. Eggs, young larvae, late pupae and newly emerged adults had relatively higher immediate survival rates than the other experimental groups. Heat treatment at the egg and larval stages had no impact on development to adulthood and on female fecundity, while it significantly reduced the survival rate of larvae but not of eggs. Brief exposure to high temperature during the early pupal stage and as adults depressed female fecundity whereas exposure during the late pupal stage had no effect.

Drought characterization across agricultural regions of China using standardized precipitation and vegetation water supply indices

Understanding the spatiotemporal dynamics of drought and its potential effect on crop production is critical in decision-making processes to support sustainable food production under climate change. This is especially true for China, the largest producer of cereal crops in the world, where production losses could significantly impact the global food chain. Here, we utilized global remote sensing products to study the spatiotemporal dynamics of meteorological and agricultural droughts across all of China during 1982–2018 and their potential linkage with winter wheat and summer corn yield losses since 2000. Specifically, we derived the agricultural Standardized Precipitation Index (aSPI; at 1, 3, and 6-month scales) and the Standardized Vegetation Supply Water Index (SVSWI) and explored their regional-scale dynamics across four sub-regions of China. Results suggest that the frequency of extreme drought events has increased in China since 2000, mostly affecting the winter wheat growing season (i.e., December–May) across North China. This increased frequency of drought events followed consistent spatiotemporal patterns of 3-month aSPI, mostly affecting Northwest/North China, Qinghai-Tibet, and South China during April, December, and May, respectively. The 3-month aSPI and SVSWI anomalies showed a good correlation with winter wheat yield anomaly across the Qinghai-Tibet area and corn yield across South China. The summer corn yield across all sub-regions and winter wheat yield across some agricultural zones in North China showed significant decreasing trends since 2000. This study provides a useful understanding of the spatiotemporal dynamics of agricultural drought and its potential implications for crop production in China.

The optimal scheme of summer maize in Shandong under the control of water and fertilizer

In order to explore a set of summer corn water and fertilizer management scheme suitable for Shandong region. The effects of dry matter, yield and fertilizer partial productivity management of summer maize under different irrigation amount (69.5 mm,120.5mm, recorded as W1, W2), different nitrogen application (143,190,235 kg/hm 2, recorded as N1, N2, N3) and phosphorus (65, 95, 115 as P1, P2, P3) on yield were significant (0.05), among which the comprehensive score of W2N2P2 was much higher than that of other treatments. According to the above analysis, the W2N2P2 treatment can be used as the best water and fertilizer ratio in this study area.

Effects of returning materials on the electrical conductivity of reclaimed soil and crop yield

In order to explore the maturation effects of different returning materials in the soil reclamation of abandoned homesteads, this paper studied the characteristics of the soil conductivity profile distribution after adding fly ash, organic fertilizer and curing agent three kinds of returning materials, and the three consecutive years of crops yield. The results showed after three consecutive seasons, the soil conductivity of the cultivated layer decreased by applying organic fertilizer treatment, and the deep soil conductivity increased, which can reduce the possibility of secondary salinization. Crop yields of different returning materials are different. Compared with the other two returning materials, the application of organic fertilizer can better mature the abandoned homesteads and reclaim the soil, and promote the growth of winter wheat and summer corn.

Effects of yellow peach moth Conogethes punctiferalis egg age on parasitism and oviposition behaviour of four indigenous Trichogramma strains in China

ABSTRACT The yellow peach moth, Conogethes punctiferalis (Guenée) has become a major insect pest in Huang-Huai-Hai summer corn region of China in recent years. Larvae directly threatens the yield and quality of corn by boring into corn ear and feeding. Currently, there are few studies to use the parasitoids, Trichogramma, to control the pest C. punctiferalis, so this study firstly evaluated the parasitism, suitability and oviposition behaviour of Trichogramma on C. punctiferalis eggs at different ages in laboratory. We found that C. punctiferalis eggs at different ages could be parasitised by four Trichogramma strains, but the number of parasitised eggs gradually decreased with egg age. Among them, the Xd strain of T. dendrolimi exhibited a better acceptance to old age eggs, which parasitised 12.8 host eggs within 24 h. The percentage of female progeny of Xd strain was the highest among the four strains when young eggs were provided. Parasitoids took more drilling time on old eggs than that on young ones, however, the Xd strain took 37.07s, 36.60s and 44.27s on young, middle and old eggs, respectively, and with no significant difference. The current study has shown that the Xd strain of T. dendrolimi performed better on the parasitism, the acceptance to old age eggs, the host handing time and the suitability of progeny than other strains, indicating that this strain may be a potential biocontrol agent for C. punctiferalis.

Long Term Crop-Livestock Managements on Physical Soil Attributes and Total Organic Carbon

Crop-livestock system (CLS) based on summer crops, as soybean and corn, in rotation with oat+ryegrass pasture in winter for dairy products, is the most adopted productive system at the southern region of Paraná, Brazil. Although its management needs to be evaluated, in order to improve its sustainability. In this sense, this study aimed to measure the impacts of management practices of five smallholder farms on soil quality, considering the soil use history. Soil samples were collected to determine soil bulk density (BD), macroporosity (Ma), microporosity (Mi), weighted mean diameter (WMD) in each area under CLS, summer pasture and native forest, as a control. Areas under CLS altered soil physical attributes (higher BD and Mi and lower Ma) in relation to the non-anthropized area as a consequence of animal trampling. However, the conservationist management adopted, with the soil cover maintenance along with years of minimum tillage, the use of grasses with aggressive roots along with the winter period, did not culminate in limitations of soil functions. Soil structure dynamics needs to be investigated to better determine the biological and physical influence on the formation of soil aggregation.

Grey Correlation Analysis of Summer Corn Yield and Main Meteorological Factors

Grey Correlation Analysis of Summer Corn Yield and Main Meteorological Factors

A solving approach for fuzzy multi-objective linear fractional programming and application to an agricultural planting structure optimization problem

In this paper, an algorithm is presented to solve fuzzy multi-objective linear fractional programming (FMOLFP) problems through an approach based on superiority and inferiority measures method (SIMM). In the model for the proposed approach, each of fuzzy goals defined for the fractional objectives and some of constraints have fuzzy numbers. To achieve the highest membership value, SIMM is adopted to deal with fuzzy number in constraints, then a linear goal programming methodology is introduced to solve the problem in which the fractional objectives is fuzzy goals. A case of agricultural planting structures optimization problem is solved to illustrate the application of the algorithm. The results show that winter wheat and summer corn acreage should be 38,386.4 ha, and cotton acreage should be 20,669.6 ha. Because of high risk in cotton cultivation at present, the ratio of grain planted area to cotton planted area is unreasonable. An improved support in policy is necessary for the government to enhance the enthusiasm of farmers to plant cotton and sustain the development of cotton market in the long term.

What type of Bt corn is suitable for a region with diverse lepidopteran pests: A laboratory evaluation

ABSTRACT Transgenic crops that produce Bacillus thuringiensis (Bt) toxins are effective tools for controlling lepidopteran pests. However, the degree of susceptibility to Bt toxins differs among various pest species due to relatively narrow spectrum and high selectivity of such toxins. Bt corn hybrids for Chinese market were designed to target Asian corn borer Ostrinia furnacalis (Guenée), while their efficacy against other lepidopteran pests are not well defined, such as Conogethes punctiferalis (Guenée), Helicoverpa armigera (Hübner), Agrotis ypsilon (Rottemberg), and Mythimna separata (Walker), which are also important lepidopteran pests on corn in the Huang-Huai-Hai Summer Corn Region of China. To determine what type of Bt corn is suitable for this region, the efficacy of five Bt toxins, i.e., Cry1Ab, Cry1Ac, Cry1F, Cry2Ab, and Vip3A, to these five lepidopteran species was evaluated in laboratory. Both O. furnacalis and C. punctiferalis showed similar high susceptibility to all five Bt toxins. A. ypsilon and M. separate were less sensitive to Cry1Ab and Cry1Ac than the other species. H. armigera, A. ypsilon and M. separate were less sensitive to Cry1F than O. furnacalis and C. punctiferalis. H. armigera was more sensitive to Cry2Ab than other tested species. All five species were equally sensitive to Vip3A, though their LC50s were all relatively higher. These findings suggest that the first generation Bt corn expressing single Cry1 toxin should not be the first choice because of the potential risk of control failure or less efficacy against H. armigera, A. ypsilon or M. separate. The second-generation Bt corn expressing Cry1 and Cry2 toxins, or the third generation Bt corn expressing Cry1, Cry2 and Vip3A toxins might produce better protection of corn in the Huang-Huai-Hai Summer Corn Region of China.

Baseline susceptibility and resistance allele frequency in Ostrinia furnacalis related to Cry1 toxins in the Huanghuaihai summer corn region of China

Ostrinia furnacalis (Guenée) is one of the most destructive pests of corn and is a major target of transgenic corn expressing Bt (Bacillus thuringiensis) toxins in the Huanghuaihai summer corn region of China. Prior to the widespread commercialization of transgenic Bt corn, it is necessary to estimate baseline susceptibility to Bt toxins and Bt toxin resistance allele frequencies in O. furnacalis. The median lethal concentration (LC50 ) values of the Bt toxins Cry1Ab, Cry1Ac and Cry1F for 15 different populations ranged from 0.887 to 1.617, 1.251 to 2.594 and 4.146 to 6.465 ng cm-2 , respectively. The LC99 values of 93, 45, and 197 ng cm-2 for Cry1Ab, Cry1Ac and Cry1F, respectively, killed > 99% of individuals of eight O. furnacalis populations collected in 2017 and were identified as diagnostic concentrations for monitoring susceptibility in O. furnacalis populations in this region. Using the F2 screening method with these diagnostic concentrations, the resistance allele frequencies related to Cry1Ab, Cry1Ac and Cry1F were found to be 0.002 (0.000283-0.006484), 0.001 (0.000030-0.004295) and 0.001 (0.000030-0.004295), respectively, in 2018. Fifteen populations of O. furnacalis collected in the Huanghuaihai summer corn region of China were all susceptible to Cry1Ab, Cry1Ac and Cry1F toxins, and the susceptibility showed no significant variation among these O. furnacalis populations. The estimated resistance allele frequency to Cry1Ab, Cry1Ac and Cry1F was rare in this region. This provided essential knowledge for making the decision to commercialize Bt maize, and monitoring resistance development and evaluating resistance management strategies in the future in the Huanghuaihai summer corn region of China. © 2020 Society of Chemical Industry.

Scarification in no-tillage: soil physics and plant development

No-tillage is conservationist soil management for agricultural production and it is based on soil cover by crop residues and restricted mobilization to the sowing line. However, its structure can be affected by the excessive compaction resulting from the traffic of machines. The objective of this study was to evaluate soil physical properties and crop performance in no-tillage with and without scarification, combined with different successions of plant species, in a Humic Cambisol. For this, the species of black oat, wheat and forage turnip were cultivated in winter, and later, corn and beans in summer. Soil samples were collected at the beginning and at the end of the experimental period, while evaluations of plant yield were carried out in the final stage of development. Soil scarification reduces relative density (RD) and soil resistance to penetration (RP) after preparation of soil, with effect restricted to the surface layer. Such effects persist for one year, however RD and RP increase over time, regardless of soil management. RP is more sensitive for evaluation of soil compaction and correlates positively with RD, with exponential adjustment. The aerial biomass of black oat, wheat and forage turnip was not affected by soil scarification, and crop yield of beans and corn showed to be more related to the previous cultivation than the scarification in no-tillage.

Improving soil properties and grains yield of winter wheat and summer corn under residue management strategies

AbstractIn this study, a 6‐year field experiment was conducted to explore the effects of different amounts of corn stover returned to the field on soil properties and grain yield of double‐cropped of winter wheat and summer maize. A randomized block design with three replications was employed including three treatments: based on all stalks of winter wheat returned to the field, (1) all summer maize stalks were mechanically pulverized and returned to the field (SR); (2) a half of summer maize stalks were mechanically pulverized and returned to the field (1/2 SR); and (3) all summer maize stalks were fully removed (control; CK). Compared with CK, the yield of summer maize and winter wheat were increased in both SR and 1/2SR. The total soil porosity, water‐stable aggregate content, and organic matter content were significantly higher in both SR and 1/2SR treatments than those in CK. The total P and available K were increased in both SR and 1/2SR, compared with those in CK. However, differences in soil properties and grain yield were not significant between SR and 1/2SR. These results indicated that corn stover returned to the field could significantly improve soil properties and yield. It can maintain soil sustainability and provide a high‐quality soil environment through treatment of 1/2SR, and the efficient use of straw can be achieved by using the remaining half of the straw for biomass energy. Overall, our data provided a basis for the use of stover resources to keep a sustainable soil production capacity.

Downscaling Solar-Induced Chlorophyll Fluorescence Based on Convolutional Neural Network Method to Monitor Agricultural Drought

Agricultural drought is a frequent global phenomenon. Solar-induced chlorophyll fluorescence (SIF) is a by-product of photosynthesis that can be used to monitor vegetation growth and agricultural drought. The global 0.05° spatial resolution data set has been obtained using the data-driven algorithm method. However, the broken farmland is not conducive to regional agricultural drought monitoring. Hence, 0.05° SIF products should be downscaled. On this basis, a convolutional neural network (CNN) downscaled work was conducted in this article to obtain 0.008° spatial resolution SIF results. The downscaled SIF and land surface temperature (LST) data were used to establish the temperature fluorescence dryness index (TFDI). The new TFDI was subsequently used for monitoring agricultural drought in Henan province (China) during the corn-growing season (from June to October 2013-2017). Results showed that the downscaled SIF data exhibit a good correlation with gross primary productivity (GPP) from the Moderate Resolution Imaging Spectroradiometer (MODIS) than 0.05° SIF products. During the study period, the soil moisture fluctuation corresponded well with precipitation, and the value of TFDI had an opposite fluctuation with soil moisture. Meanwhile, the annual averaged TFDI had a high correlation with summer corn yield (R = -0.84). In conclusion, the SIF results through the CNN-based downscaled method were reliable, and the new TFDI was suitable for region agricultural drought monitoring.

Mapping summer soybean and corn with remote sensing on Google Earth Engine cloud computing in Parana state – Brazil

ABSTRACT Brazilian farming influences directly the worldwide economy. Thus, fast and reliable information on areas sown with the main crops is essential for planning logistics and public or private commodity market policies. Recent farming practices have embraced remote sensing to provide fast and reliable information on commodity dynamics. Medium-to-low resolution free orbital images, such as those from Landsat 8 and Sentinel 2, have been used for crop mapping; however, satellite image processing requires high computing power, especially when monitoring vast areas. Therefore, cloud data processing has been the only feasible option to deal with a large amount of orbital data and its processing and analysis. Thus, our goal was to develop a method to map the two main crops (soybeans and corn) in Paraná, one of the major Brazilian state producers. Landsat-8, Sentinel-2, SRTM+, and field data from 2016 to 2018 were used with the Simple Non-Iterative Clustering segmentation method and the Continuous Naive Bayes classifier, to identify cropped areas. A minimum global accuracy of 90% was found for both crops. Comparison with field data showed correlations of 0.96 and agreement coefficients no lower than 0.86. This ensures mapping quality when using Sentinel and/or Landsat imagery on the GEE platform.

Manure injection and rye double cropping increased nutrient recovery and forage production

AbstractDouble cropping forage cereal rye (Secale cereale L.) with corn (Zea mays L.) and injecting liquid dairy cow (Bos taurus L.) manure in the fall may increase manure nutrient utilization and total forage production. Although potentially economically and environmentally beneficial, these practices have not been widely adopted by Northeastern U.S. farmers. This 2‐yr full‐factorial experiment conducted in Pennsylvania quantified the effects of (a) rye management (RyeM; early terminated cover crop, CC vs. double crop harvested approximately 1 wk later, DC) and (b) manure application method (ManM; unincorporated broadcasted manure, BM vs. shallow disk injected manure, IM) on rye biomass, rye apparent manure nitrogen and phosphorus recovery (ANR and APR, respectively), subsequent corn silage yield, and total forage production (DC + summer corn silage) and the effect of ManM on DC forage nutritive value. Double cropping increased rye biomass 143%, ANR 119%, APR 126%, and total forage production 29–44% compared to CC. While IM did not increase net returns on rye silage production compared to BM, IM improved rye forage nutritive value by increasing ANR by 84%, rye crude protein by 29%, net energy of lactation by 10%, and reduced neutral detergent fiber (NDF) by 10%. Injecting manure also increased summer corn yield 21% and total forage 13% when rye was harvested as DC compared to DC with BM. Farmers adopting DC can increase total forage production and nutrient recovery and, when combined with IM, forage production and rye quality can potentially be improved.