Spring Crops Research Articles

Sugar beet development under dynamic shade environments in temperate conditions

Abstract In Wallonia (Belgium) almost half of the arable land undergoes a four-year crop rotation. Winter crops often follow spring crops within the rotation scheme. This is a challenging context to implement silvoarable agroforestry (AF) systems, in terms of species choice, plot design, and tree management, since the periods of crop resource capture clearly differ. AF is defined here as the deliberate introduction of trees in the cropped area. Combining spring crops with trees induces an important overlap of the growing period of both plants which has an impact on one of the primary resources for both plants: light. In this study, we monitored an important spring crop for the region, sugar beet (Beta vulgaris L.). We quantified the impact of the shade environment on sugar beet morphology, growth dynamic, productivity and quality. We used artificial shade to isolate the impact of shade from other possible interactions in agroforestry systems. The field experiment was conducted over two consecutive years (2015 and 2016) on the experimental farm of Gembloux Agro-Bio Tech, Belgium. We installed the shade structures so as to reproduce a North-South and East-West tree line orientation. The experiment simulated canopy shade of late-flushing hybrid walnut by overlapping military camouflage netting. In 2015, the North-South orientation induced two distinct shade conditions: periodic shade (PS) and continuous shade (CS). In 2016, the East-West orientation created two periodic shade treatments, one during the morning (PSam) and one in the afternoon (PSpm). In both experimental years, shading was imposed from mid-June until harvest, resulting in 132 days of shade in 2015, and 140 days in 2016 on a growing season of 192 (2015) and 188 (2016) days in total. Sugar beet under shade tended to produce longer petioles. In 2015, at the first sampling date, we observed a higher specific leaf area and single leaf area under the CS and PS treatment, while there were no differences in 2016. All the shade treatments significantly changed the dry matter partitioning between the sugar beets compartments. Under the shade treatments, the quantity of biomass allocated to the leaves was significantly reduced as compared to the proportion of biomass for the petioles. Likewise, quantity of root dry matter formed per gram of shoot dry matter was reduced under shade. Thus, at harvest, all the shade treatments significantly reduced the final root dry matter and sugar yield. Furthermore, sugar beet quality, and more specifically sugar extractability, was affected by shading but to a lesser extent than for the final root dry matter and sugar yield.

The Application of Soil-Agroclimatic Index for Assessing the Agronomic Potential of Arable Lands in the Forest-Steppe Zone of Russia

An assessment of the agronomic potential of arable lands in the forest-steppe zone of Russia (by the example of separate soil-agronomic districts) on the basis of the soil-agroclimatic index developed under the supervision of I.I. Karmanov is considered. The agricultural areas (64) separated on the territory of Russia and characterizing soil-agroclimatic conditions for cultivation of major and accompanying crops are differentiated into soil-agronomic districts (SADs) with due account for the administrative division of the country. A large diversity of agroclimatic and agronomical conditions creates the prerequisites for the inclusion of administrative regions into different SADs. The SADs concept implies a detailed analysis of information on the soil properties, geomorphic conditions, and farming conditions. The agronomic potential for major crops in the key SADs in the forest-steppe zone of the East European Plain (Voronezh and Penza oblasts) is high, though it is 25–30% lower than that in the North Caucasus (for winter wheat, sugar beet, sunflower, and spring barley) and in Kaliningrad oblast (for oats). In Western Siberia (Tyumen, Omsk, and Novosibirsk oblasts) and Eastern Siberia (Krasnoyarsk region and Irkutsk oblast), the agronomic potential of spring crops (wheat, barley, and oats) is only utilized by 35–45% in comparison with their European analogues. In the Far East with its monsoon climate and soil conditions (meadow podbels, brown forest soils), the crops characteristic of the European forest-steppe (soybean, rice, sugar beet) and the Trans-Ural forest-steppe (spring wheat) are cultivated. Their biological potential is utilized by only 50–60% in comparison with the European analogues. The materials of this study give us information on the degree of correspondence between the soilagroclimatic potential of the territory and the biological potential of cultivated crops. This is important in the context of improving the natural-agricultural zoning of Russia and its information support.

Evaluation of the influence of climate change on the productivity of millet in the central part of Ukraine

Climate change is a change of climatic conditions in the global atmosphere and on the Earth in general (or within its individual zones or territories) caused directly or indirectly due by the human activity on the planet, which are overlaid on the natural climatic variations (fluctuations) and ob-served during comparable periods of time.
 Both the climate of Ukraine and the global climate are changing, but warming within our terri-tory progresses even faster than in other regions of the Northern Hemisphere.
 Ukraine in general and southern regions in particular are becoming increasingly vulnerable to climate change – droughts, extremely high temperatures, inefficient precipitation, reduced irrigated area cause of precipitation amount and regime, severer and more long-lasting droughts, reduced water availability.
 The majority of arable land in Ukraine are located in zones of unstable and insufficient humidity, it is quite possible that for plant growing, especially for growing winter crops and early spring crops, climate change will rather have a positive effect than negative one.
 Among the main types of cereals millet is the most common one. It is valuable for its groats, which is known by its high eating quality.
 Millet as a fast-growing crop having a certain agrotechnical importance: it is used as a backup crop for re-sowing dead winter crops and is suitable for stubble and post-harvest sowing, it also can be used as a cover culture for perennial grass.
 Millet is one of the most drought-resistant and heat-resistant crops. It is able to withstand heat injuries which is very important in arid areas and during dry years, when other grain crops have reduced yield. Millet suffers less from pests and diseases than other crops.
 The task was to evaluate the agro-climatic conditions of millet crops formation in the central part of Ukraine under conditions of climate change. The study of the impact of climate change on the formation of millet productivity for different time intervals was performed by comparing the data of the RCP scenario and the average long-term climatic and agro-climatic parameters. The in-fluence of agroclimatic conditions on the dynamics of increase of agroecological yield of different levels is also assessed.

Effect of Bacterial-algal Biostimulant on the Yield and Internal Quality of Lettuce (Lactuca sativa L.) Produced for Spring and Summer Crop

Plant biostimulants can enhance crop nutrition status, stress tolerance, yield and quality in environment-friendly manner. The aim of this study was to determine the effect of an algae and bacteria preparations on the yield and nutritional parameters of leaf and romaine lettuce cultivated for spring and summer crop. The application of a combined biostimulant consisting of plant growth-promoting bacteria (Bacillus licheniformis, Bacillus megatherium, Azotobacter sp., Azospirillum sp., and Herbaspirillum sp.) and fresh water algae (Chlorella vulgaris) was done by watering the lettuce every 14 days, and a determination of the fresh weight, total antioxidant capacity, and total carotenoids content was performed. The result revealed that the application of bacterial-algal preparation significantly affected the plant weight of both romaine and leaf lettuce in spring and summer seasons. The highest increase in the weight of romaine lettuce reached 18.9% in the spring crop, while in the case of leaf lettuce, biostimulant treatment led to a 22.7% higher weight in the summer crop. Total antioxidant capacity and total carotenoids content showed increased values in the summer crop of romaine lettuce, while for the leaf lettuce there were no differences between treatments. Therefore, the positive effect of bacterial-algal treatment on lettuce yield, total antioxidant capacity and total carotenoids confirm that it could be applied for improving romaine lettuce yield quality and quantity, especially in stress, summer conditions.

Suppressive effect of black oat, Avena strigosa, KH1a on Meloidogyne spp.

Summary The suppressive effect of a black oat, Avena strigosa, breeding line KH1a on Meloidogyne spp. was examined in pot tests and on Meloidogyne incognita in pot and field tests. In pot tests, roots of black oats were examined 42-46 days after inoculation of 500 second-stage juveniles. There were significantly fewer egg masses on the roots of KH1a than on 12 black oat cultivars examined. KH1a was a poor host for four isolates of M. incognita, two isolates of M. arenaria and one isolate of M. javanica, and a non-host for one isolate of M. hapla. The effect of autumn and spring cropping of KH1a on soil nematode density was examined in M. incognita-infested fields. Nematode density after autumn cropping of KH1a was significantly lower than that after susceptible black oat, resulting in significantly lower Pf/Pi in KH1a (0.10 and 0.13) than in susceptible black oat (0.42 and 0.74). Damage indices of the succeeding crop, sweet potato, were significantly lower in KH1a plots than in susceptible black oat plots. In spring cropping, there were significantly fewer soil nematodes in KH1a plots than in susceptible black oat plots 3 weeks after cultivation. In both autumn and spring cropping, there was no significant difference in soil nematode density between KH1a and bare fallow. These results suggested that KH1a is a good alternative to current susceptible cultivars for the management of M. incognita.

Ocena agrotechniczna i ekonomiczna współrzędnej technologii uprawy kminku zwyczajnego (Carum carvi L.)

A study was carried out in 2013-2014 on caraway (Carum carvi L.), which is a biennial plant grown alone or together with a spring crop. The aim of the study was an agrotechnical and economic assessment of technologies for intercropping of caraway with selected three species of spring crops. The study showed that the highest caraway fruit yields in the second year were obtained in the variant in which the species was grown together with field pea. The profitability of this variant was increased by area-based subsidies for legumes and reduced outlays for mineral fertilizers. The highest value for pea as a species intercropped with caraway was confirmed by economic indicators such as soil productivity, net farm income, and production profitability. The second most suitable crop for intercropping with caraway was dill. It has similar agrotechnical requirements as caraway, but has the disadvantage of a very late harvest time, which slows the development of the main crop and reduces the yield of caraway the following year. In this variant lower values were obtained for the economic indicators than in the case of caraway grown with pea. The least suitable species for intercropping with caraway proved to be white mustard, whose intensive growth and accompanying high demand for water, nutrients and light substantially limited the development and yield of caraway. Due to the relatively low caraway yield and high cost of mustard cultivation, this variant resulted in the lowest economic indicators.

Missouri Spring Freeze Event and Crop Loss Analysis for the Years 1982-2015

A spring freeze is an unexpected freeze event occurring in late spring that can result in severe domestic crop loss. These events coincide with seasonal weather conditions that promote early crop development. As a consequence, early growth is most susceptible to freeze damage. Spring temperature fluctuations pose significant threat to crop yield and growth, when compared to onsistently cold springtime temperatures. In this study, a thirty-four-year span (1982 to 2015) of historical climate, agricultural and crop insurance data for Missouri was analyzed. Risk analysis was performed for each Missouri county to determine statistical relationships between crop loss and springtime warm-cold temperature fluctuations. Statewide, several regions were identified as having an increased susceptibility to freeze events, with Lafayette County emerging as the state’s leading county in agricultural losses due to freeze events. The window for peak freeze damage for Lafayette County was identified as the last week of March through the first week of April. The years 1985, 1996 and 2007 stood apart in the dataset as they correspond to the highest crop damages on record. Each of these years also corresponds to a doubling of severity in the reported crop losses.

Mogućnost suzbijanja korova združenim gajenjem jarog stočnog graška sa ovsem

Field pea is a high quality fodder crop of a short vegetation period. The production of field peas as a spring crop reduces the risk of yield losses due to unfavourable winter conditions, improves soil characteristics and ensures high quality fodder at the end of the spring. Intercropping with oats is often carried out due to the fact that field pea requires support and both species have similar developmental stages. The field experiment was set up at the Institute for Animal Husbandry in Zemun in 2017, in order to study the forage yield and the possibility of weed control by cultivating the mixture of field pea and oats. Serbian varieties of field pea NS Junior and oats cultivar Dunav were included in the trial, intercropped according to the 'additive model' in two ways: 100:15% and 100:30% pea : oats, when compared to monoculture (100% pea and 100% oats). In the 100:15% intercrop model of field pea and oats , the number of weed units and their fresh and dry weight were lower than in monocultures, while the higher presence of weeds in the 100:30% model was significantly affected by the high number and biomass production of weed species Ambrosia artemisiifolia. The cultivation of oats and field pea in the mixture significantly increased the yield of fresh and dry biomass, when compared to monocultures, while there was no significant difference in yield between the different methods of peas and oats (100:15% and 100:30%) intercropping. The higher share of oats at the crop establishment stage did not increase the forage yield, indicating the dominant contribution of the field pea biomass in the mixture.

The Effect of Wireworm Agriotes spp. in Many Types of Potatoes

The present study demonstrate the infection (injury and damage) of wireworm on potato crop in spring and autumn season. This study was conducted in Abu- Greeb fields in Baghdad– Iraq during 2009 – 2010 In order to assessment the damage caused by wireworm Agriotes spp. on four type of growing Solanum tuberosum crop (Rodeo, Lotona, Bleni, Deseri) in spring and autumn season. The results of this study showed that Agriotes spp. was more damage in spring season more than autumn season. Percentage of the numbers of damage potato tuber to the four types was 1.81, 4.87, 6.66, 8.33 % respectively. While it was 6.55, 3.63, 10.52, 9.09 % total weight of Rodeo, Lotona, Bleni, Deseri , respectively. The Rodeo type was more injury in spring season with ratio of 11 tuber number. The result showed that the potato was damage in spring season more than autumn season and this may be due to the presence of the larvae near soil surface that liege with temperature during season. Also may be due to size of potato tuber which cultured large tuber with wide surface area be more damaged and injury.

Динаміка формування площі листя рослин ячменю ярого залежно від впливу норми висіву та позакореневих підживлень

У статті представлені результати досліджень, проведених протягом 2015, 2016 рр. на дослідному полі ХНАУ ім. В. В. Докучаєва щодо впливу норм висіву і позакореневих підживлень на варіабельність показників площі листя і зміну лінійних розмірів другого листка рослин ячменю ярого. Встановлено, що досліджувані варіанти норми висіву та позакореневих підживлень полімерним добривом «Вуксал» істотно впливали на площу листової поверхні рослин і лінійні розміри другого листка рослин ячменю ярого. Максимальні показники площі листя рослин у досліджувані фази розвитку забезпечувала норма висіву 5,0 і 5,5 млн нас./га. Кращим варіантом позакореневого підживлення посівів ячменю ярого, який забезпечував формування найбільшої площі листя та максимальні лінійні розміри другого листка був варіант дворазового внесення препарату «Вуксал» – у фазу трубкування і колосіння в нормах 1,0 л/га.
 The article presents the results of studies conducted during 2015, 2016. On the experimental field of KHNAU named after V. V. Dokuchaiev concerning the influence of seeding rates and foliar fertilization on the variability of leaf area parameters and changes in the linear dimensions of second leaves of spring barley plants. It was found that the investigated variants of the seeding rate and foliar fertilizing with polymeric fertilizer «Vuksal» significantly influenced the area of the plant leaves and the linear dimensions of the second leaf of the spring barley plants. The maximal parameters of the leaf area of plants in the research phases of development provided a seeding rate of 5,0 and 5,5 million/ha. The best option for foliar top dressing of barley spring crops, which provided the formation of the largest leaf area, and the maximum linear dimensions of the second leaf was a variant of double application of the «Vuksal» – during the time of exit into the tube and earing in doses – 1,0 l/ha.

Effects of Climatic Conditions and Management Practices on Agricultural Carbon and Water Budgets in the Inland Pacific Northwest USA

AbstractCropland is an important land cover influencing global carbon and water cycles. Variability of agricultural carbon and water fluxes depends on crop species, management practices, soil characteristics, and climatic conditions. In the context of climate change, it is critical to quantify the long‐term effects of these environmental drivers and farming activities on carbon and water dynamics. Twenty site‐years of carbon and water fluxes covering a large precipitation gradient and a variety of crop species and management practices were measured in the inland Pacific Northwest using the eddy covariance method. The rain‐fed fields were net carbon sinks, while the irrigated site was close to carbon neutral during the winter wheat crop years. Sites growing spring crops were either carbon sinks, sources, or neutral, varying with crops, rainfall zones, and tillage practices. Fluxes were more sensitive to variability in precipitation than temperature: annual carbon and water fluxes increased with the increasing precipitation while only respiration increased with temperature in the high‐rainfall area. Compared to a nearby rain‐fed site, irrigation improved winter wheat production but resulted in large losses of carbon and water to the atmosphere. Compared to conventional tillage, no‐till had significantly lower respiration but resulted in slightly lower yields and water use efficiency over 4 years. Under future climate change, it is expected that more carbon fixation by crops and evapotranspiration would occur in a warmer and wetter environment.

Nitrate leaching in soybean rotations without nitrogen fertilizer

Nitrate leaching is a primary pathway of nitrogen loss from agricultural systems, and is affected by both tillage and cropped species. However, there is little information on conservation systems without nitrogen fertilization. Nitrate leaching was assessed in soybean (Glycine max) cropped in rotation with the following cover crops under no-till and chiseling: ruzigrass (Brachiaria ruziziensis), grain sorghum (Sorghum bicolor), pearl millet (Pennisetum glaucum), forage sorghum (Sorghum bicolor), Sunn hemp (Crotalaria juncea), triticale (X Triticosecale) and sunflower (Helianthus annuus). Ruzigrass and grain sorghum cropped in the fall/winter resulted in similar NO3 − leaching, which was greater under sunflower than under triticale, likely due to high N uptake and immobilization in plant residues. Sunn hemp as a spring crop resulted in higher NO3 − leaching than pearl millet at two locations and forage sorghum at one location likely due to a higher N input by biological fixation. Millet resulted in the lowest N leaching by depleting the soil solution. Chiseling/fallow resulted in higher nitrogen leaching as compared with non-fixing N cover crops. Even when N is not applied, it is important to intensify cropping systems in tropical environments using cover crops with vigorous root systems and high N demand, which prevent N leaching, as well as provides N to the following crop as the straw is mineralized.

Assessment of heat supply of vegetation period within the northern grain-seeding territory of Kazakhstan

Introduction. The existing agroclimatic handbooks in Kazakhstan are outdated both in informational and technological senses. Therefore necessity of agroclimatic resources reassessment arose.
 Purpose. Research of heat supply of vegetation period within the Northern grain-seeding territory of Kazakhstan.
 Methods. Data of meteorological stations for period of 1981-2014 were used. Methods of statistic and climatologic processing of data were applied. The agroclimatic maps were drafted using ArcGIS 10.1 software.
 Results. The article describes a thermal regime, duration and heat supply of vegetation period within the territory of 4 northern oblasts of Kazakhstan. The territory of Northern Kazakhstan under study hascontinental climate. Average annual air temperature at the area under study increases from the North to the South from 1.8 °C to 5.3 °C. Average July air temperature at the area changes from 18.5 °C to 23.6 °C and average January air temperature – from minus 12.8 °C to minus 17.4 °C. Duration of vegetation period for early spring crops constitutes 172-193 days, for late spring crops – 136-162 days and for warm weather crops – 89-124 days. Daily range of air temperature is 11.4-14.7 °C and that means rather high quality of grain. Sum of active temperatures exceeding 10 °C increases from the North to the South from 2100 °C to 3400 °C. Vegetation period is 90% provided by sum of active temperatures exceeding 10 °C within the range of 2000-2900 °C. Maps of heat supply and vegetation period duration were also drafted.
 Conclusions. In the north of the territory under study thermal sources satisfy demands of soft and common sorts of wheat but are not enough for sunflower and maize, in the south they are enough for wheat, all sorts of sunflower and middle-late sorts of maize.

Agrophysical and Biological Properties of Drainage Soils in Land Reclamation

This paper presents the results of the research carried out in the All-Russian Research Institute of Reclaimed Lands. It has been established that land improvement techniques increased the integral index of physical soil conditions from 0.41-0.60 to 0.80-0.86. The soil demonstrated a greater total number of microorganisms, as well as certain physiological groups such as actinomycetes, autochthonous and especially nitrogen-fixers; but the number of fungi and denitrifiers, as well as the fungi causing the Fusarium wilt of the plants, decreased.Average crops increase achieved with the help of deep reclaiming band tillage of drained gleyish soil to depth 50-60 cm was 9.0-24.1% in both wet and dry years. This land improvement technique effect lasts for two-three years or longer. The ridged plowing compared to the ordinary plowing raised the spring crops by 0.55-0.61 ton/ha (by 16.9-17.5%) without making any additional expenditures.

건조스트레스가 감자 식물체 무기성분 및 생육에 미치는 영향

Yield of potato is largely influenced by drought stress. This study was conducted in Gangneung and Cheongju during the spring cropping of potato. Potatoes in the Gangneung area were affected by drought but there was no damage due to drought in Cheongju. During the early-growth stage, the contents of inorganic components like available phosphate and growth characteristics of the potato leaf in Cheongju were significantly higher than those in Gangneung but there was no difference after the flowering stage. It was considered that the potato plants cultivated in Cheongju could vigorously grow than that of Gangneung under drought stress. In addition, the content of calcium (Ca), which is a secondary messenger related to aging, was found to be higher in potato plants grown in Cheongju than in Gangneung and accumulated more quickly in potato plants of Cheongju. Because magnesium (Mg) was also found to be higher in potato plants from Gangneung by a wide margin, this phenomenon was thought be related with drought stress. The amounts of all inorganic components absorbed from soil were higher in Cheongju than in Gangneung, showing a relatively higher plant biomass in Cheongju. Correlations of development indexes related to leaf showed less or no relation in Gangneung. According to yield characteristics of the harvest stage, although yield was greatly reduced under drought stress condition, the rate of commercial yield was not significantly affected under the drought stress condition. Consequently, it was considered that these responses to drought stress could be utilized to stabilize potato production under the stressful conditions associated with abnormal climate.

Detection of Potato virus Y in industrial quantities of seed potatoes by TaqMan Real Time PCR

Potato (Solanum tuberosum) is the largest crop in Israel. Production is based on the import of seed tubers from Europe for the spring crop. Imported tubers are generally free from virus infection. The most important virus infecting potato is Potato virus Y (PVY), which may cause severe damage to marketable yields. In Israel, tubers from the spring harvest are stored over the summer for planting in the autumn. It is important to be able to determine the infection rate of seed tuber lots from the spring harvest prior to storage. Commonly, infection is measured by sprouting tubers and measuring virus titre in the leaves using ELISA (the “Growing-On test”), which takes at least 6 weeks to give results. There is a need for a faster method to produce results, such as Taqman Real Time PCR (qPCR), for direct analysis of viral infection in tubers at harvest. To use qPCR as a diagnostic tool, it is necessary to demonstrate that both techniques give comparable results on batches of field-grown tubers. Such a comparison was performed on potential seed tuber lots of 14 different cultivars over three Israeli spring harvests (2013–2015). The agreement between the results of the two techniques was not of high statistical significance. However, the qPCR technique can distinguish well, by binary classification, between tuber lots with a low PVY infection rate (<5% by Growing On test; suitable for seed) and those unsuitable for seed (≥5% by Growing On test). Therefore, qPCR is an appropriate technique for determination of the PVY infection rate of seed tuber lots in Israel.

Sowing Date and Cultivar Effects on Assimilate Translocation in Spring Mediterranean Chickpea

Core Ideas March sowing resulted in higher dry matter, total N accumulation, and seed N content than April sowing. Seed yield up to 3320 kg ha−1 were obtained with March sowing. Seed yield was correlated negatively with dry matter translocation to the seeds. In cooler Mediterranean areas autumn sowing of chickpea (Cicer arietinum L.) is avoided because of the increased frost risk. A 2‐yr field study was conducted to investigate the potential effects of spring sowing date and cultivar on assimilate dynamics (i.e., dry matter and N accumulation, partitioning and translocation) and productivity of Mediterranean chickpea, and to assess possible N losses from plant foliage. Three local cultivars (i.e., Andros, Kassos, and Serifos) and one foreign cultivar (i.e., Zehavit‐27) were evaluated under two sowing dates (i.e., March sowing and April sowing). March sowing resulted in higher dry matter, total N accumulation, and seed N content than April sowing. Seed yield up to 3320 kg ha−1 was obtained with March sowing. April sowing resulted in a yield penalty of 22 to 50 kg ha−1 d−1 of sowing delay compared with March sowing. Seed yield was correlated negatively with dry matter translocation to the seeds and positively with dry matter accumulation during the seed‐filling period. Dry matter and N translocation efficiency reached up to 77 and 96%, respectively. High N accumulation until the beginning of seed growth and low N accumulation thereafter enhanced N translocation to the seeds. However, when early aboveground N was high (&gt;120 kg N ha−1) and the seed demands for N were low (&lt;96 kg N ha−1), N losses were observed, reaching up to 40.4 kg N ha−1. Chickpea has potential as an alternative spring crop in cooler Mediterranean areas, provided that early spring sowing is applied.

Characteristics and the Relationship of Nitrogen and Phosphorus in Soil and Water of Different Land Use Types of a Small Watershed in the Three Gorges Reservoir Area

Long-term field monitoring data was analyzed regarding the characteristics of nitrogen and phosphorus in the soil and shallow groundwater of different land use types in a typical small watershed of the Three Gorges Reservoir area. Furthermore, the relationships among soil nitrogen and phosphorus contents, concentrations of nitrogen and phosphorus in shallow groundwater, and slope surface runoff were analyzed. The results showed that the average contents of TN and NO3--N in terrace soil were significantly higher than those in sloping upland soil (P< 0.05), for which the average content of paddy terrace was highest (1.49 g·kg-1). The average contents of TP in the soil of sloping upland and mulberry-sloping upland were significantly higher than those in the soil of other land types. The average content of NO3--N in the soil of dryland terrace was highest of all land use types and its discrete degree was also largest. The slope land use type had greater impact on the concentrations of TN and NO3--N in shallow groundwater, but it had little influence on TP concentration. In addition, the shallow groundwater TN concentration and NO3--N concentration had significant positive correlation, and the average contribution rate of NO3--N to TN in five wells ranged from 67.82% to 78.51%. The monthly average concentration of TN and NO3--N in shallow groundwater changed little, only showing a significant upward trend after the fertilization stage of the two crops in spring and autumn. The average contents of TN and NO3--N in the slope soil were significantly correlated with the TN and NO3--N concentrations in the shallow groundwater, but there was no significant correlation between the TN and NO3--N concentrations in the surface runoff. When the slope surface runoff TP concentration was>0.1 mg·L-1, the average content of TP had a significant linear correlation with it. There was a significant power function relationship between the concentrations of TN and NO3--N in the surface runoff and concentrations of TN and NO3--N in the shallow groundwater, with higher correlation of NO3--N concentrations between surface runoff and shallow groundwater.

Biology and management of Avena fatua and Avena ludoviciana: two noxious weed species of agro-ecosystems.

Avena fatua and Avena ludoviciana are closely related grass weed species infesting a large number of crops around the world. These species are widely distributed in diverse agro-ecosystems from temperate to sub-tropical regions due to their unique seed traits, successful germination ecology, high competitive ability, and allelopathic potential. A. fatua is more widespread, adaptable, and problematic than A. ludoviciana. Both these species infest major winter and spring crops, including wheat, oat, barley, canola, maize, alfalfa, and sunflower, causing up to 70% yield losses depending on crop species and weed density. Chemical control has been challenged by large-scale herbicide resistance evolution in these weed species. A. fatua is the most widespread herbicide-resistant weed in the world, infesting about 5 million hectares in 13 countries. The use of alternative herbicides with different modes of action has proved effective. Several cultural practices, including diverse crop rotations, cover crops, improved crop competition (using competitive cultivars, high seed rates, narrow row spacing, altered crop geometry), and allelopathic suppression, have shown promise for controlling A. fatua and A. ludoviciana. The integrated use of these cultural methods can reduce the herbicide dose required, and lower dependency on herbicides to control these grasses. Moreover, integrated management may successfully control herbicide-resistant populations of these weed species. The use of integrated approaches based on the knowledge of biology and ecology of A. fatua and A. ludoviciana may help to manage them sustainably in the future.

Cereal leaf beetles (Oulema spp., Coleoptera: Chrysomelidae) control following various dates of wheat sowing and insecticidal treatments

ABSTRACTIn this paper, we report the sowing date and intensity of chemical control on presence of the cereal leaf beetles (CLB) on spring wheat. The CLB monitoring (Oulema melanopus L. and Oulema gallaeciana Voet.) was conducted in May–June of each year, following the announcement of the IOR-PiB in Poznań (Institute of Plant Protection, National Research Institute), that economic threshold levels in Poland of this pest is observed. For the spring sowing dates between (20 March–20 April) and late autumn sowings (21 November–7 December) larger amounts of CLB adults (1.6–1.1) in comparison to early autumn sowings (25 October–02 November) were noticed (0.4). Following the insecticidal seed treatment with imidacloprid, the occurrence of adults was 0.2–0.7 individual per stem, while the use of fungicidal treatment with triadimenol–imazalil–fuberidazol resulted in average 1.1–2.2 individual per stem. The reduction in the number of larvae per stem was 7–10 fold larger following the foliar application (pirimicarb + dimethoate + cypermethrin) compared to the seed treatment with imidacloprid. The lowest grain yield (3.83 t ha−1) from the spring crop without any insecticide was obtained. Foliar application with blend of pirimicarb + dimethoate + cypermethrin increased the yield crop by 0.41 t ha−1 (10.7%) and additionally by 0.78 t ha−1 (20.4%) to compare to the fungicidal control when imidacloprid was used. Wheat seed treatment with imidacloprid and sowing date in autumn showed to be suitable and economically efficient preventive strategies for controlling the pest population.