Crop Year Research Articles

Is it worth paying attention to actinedid mites in agricultural fields?

Agricultural management increases the seasonal dynamics of soil-dwelling organisms compared to natural habitats. Our knowledge is very poor about the relationship between seasonal changes of soil microorganisms and the microbivorous soil arthropods. To reveal these connections, we have to know more about the seasonal changes of soil-dwelling microarthropods in croplands. Actinedid mites are rarely the subject of synecological studies, however, this group regularly reaches the dominant part of mite assemblages in agro-ecosystems. In this study, we investigated the seasonal density changes of actinedid mites from two independent studies of agricultural fields. Soil samples were taken from maize and wheat fields for two years, and from newly established meadows for one year in summer and autumn in Hungary. Soil-dwelling mites were enumerated and identified at the suborder level and soil parameters were measured. Actinedid mites dominated most of our soil samples. The density of Endeostigmata was the highest in the summer and the density of Heterostigmata was the highest in the autumn within one year among different crop species, soil types, and years. Endeostigmatid mites had negative relationships with soil nitrogen parameters and positive with soil moisture. Heterostigmatid mites had various relationships with soil moisture. The ecology of actinedid mites is under-examined but their high number in agricultural fields may justify the fact that they should receive more attention. We assume that Actinedida, mainly Endeostigmata and Heterostigmata are worth to investigate in croplands as a starting point to reveal the connection between the seasonality of soil mites and soil microbiota.

Improving early prediction of crop yield in Spanish olive groves using satellite imagery and machine learning.

In the production sector, the usefulness of predictive systems as a tool for management and decision-making is well known. In the agricultural sector, a correct economic balance of the farm depends on making the right decisions. For this purpose, having information in advance on crop yields is an extraordinary help. Numerous predictive models infer accurate crop yield data from aerobiological variables and pollen analysis; this is around spring, in the middle stage of the crop year, when planning and investments are already done. The aim of this study is to anticipate accurate crop yield data at an early stage of the cropping season. In the case of olive groves in Spain, this period is in February. This work is developed for an entire province, Jaen, belonging to the region of Andalusia, in Southern Spain. The methodology uses Machine Learning algorithms together with an exhaustive analysis of predictor variables. Temporal data come from public web services, such as spatial data infrastructures of some state agencies. The processing of the satellite imagery is carried out by the geospatial processing service Google Earth Engine. The result is the early prediction of kilograms of both olive crop and olive oil, eight months prior to the beginning of the first harvesting campaigns of the year, with an average absolute error of prediction better than 26%. The relevance of this work is the early availability of predicted crop yield data together with the multi-scale applicability of the predictive models. This makes this model a useful tool for all the agents involved in olive grove management. From farmers, to agricultural technicians, researchers and scientists dedicated to the study of the olive tree, to governmental institutions and agricultural associations that provide technical support, advice and regulation to ensure responsible practices and the long-term viability of the olive industry.

Effects of continuous cropping and application of bio-organic fertilizer on photosynthetic performance, dry matter accumulation and distribution of sugar beet

One of the major problem in the cultivation of sugar beets is continuous cropping obstacle in China. In order to evaluate the effects of continuous cropping year on the photosynthetic performance, dry matter accumulation, and distribution of sugar beet, this study was conducted in the 2020–2021 crop season at the Agriculture and Forestry Sciences of Ulanqab, Inner Mongolia. A split plot system arrangement with three replications was set up to carry out the field testing. The main plots had five planting years, with the a first cropping of each growing season serving as the control (CK) and four continuous cropping treatments for one, two, three, and four years (designated as C1, C2, C3, and C4, respectively). The subplot consisted of two fertilization treatments designated as 0 kg ha−1 bio-organic fertilization (N) and 6000 kg ha−1 bio-organic fertilization (Y). The findings demonstrated that the continuous cropping impeded sugar beet photosynthesis as well as the accumulation and dispersion of the dry matter in leaf, petiole, and root. The intercellular CO2 concentration (Ci), transpiration rate (Tr), stomatal conductance (Gs), net photosynthetic rate (Pn), and SPAD value were dramatically dropped as the number of continuous cropping years increased under the crop. Compared with CK, the SPAD value, Pn, Ci, Tr, Gs of continuous cropping treatments were significantly reduced by an average of 10.09–48.21%, 14.60–43.19%, 12.00–42.86%, 7.77–43.83%, 9.61–37.68%, respectively. The dry matter accumulation of leaf, petiole, root, and the whole plant were also reduced by 11.86–49.61%, 9.58–44.77%, 17.26–53.76%, and 10.62–49.79%, respectively. With the increasing of continuous cropping year, the growth of sugar beet was significantly inhibited. Study revealed that continuous cropping had an impact on the distribution of dry matter accumulation of sugar beet; it considerably raised the dry matter ratio above ground, lowered the dry matter ratio below ground, and prevented dry matter from moving from aboveground towards root, whitch caused a decline in sugar beet root production and disturbed the root shoot ratio. Compared with CK, the root shoot ratio significantly decreased by 3.62–19.76%. Under continuous cropping stystem, the application of bio-organic fertilizer had an effect on promoting the photosynthesis of sugar beet, and regulating the distribution and transport of dry matter. The effects of bio-organic fertilizer were significantly under continuous cropping for 1–2 years. Compared with C1N and C2N, the Pn, Ci, Tr, Gs of C1Y and C2Y were significantly increased by 12.79–22.50%, 14.76–16.47%, 4.76–13.08%, 8.51–12.70%, and 13.69–18.91%, 12.17–14.60%, 5.71–15.14%, 7.58–15.41%, respectively. Dry matter accumulation of leaf, petiole, root, whole plant were significantly increased by 8.32–16.18%, 10.80–13.33%, 14.93–20.13%, 14.12–15.43%, and 10.65–15.32%, 6.58–15.63%, 15.37–20.94%, 12.68–16.85%, respectively. Nonetheless, the root shoot ratio increased by 4.58–8.56% and 4.52–7.35%. Above all, Under continuous cropping conditions, the application of 6000 kg ha−1 bio-organic fertilizer could effectively promote the photosynthesis of sugar beet, and better regulate the distribution and transport of dry matter of sugar beet. These results can provide scientific basis for bio-organic fertilizer to alleviate the problem of sugar beet continuous cropping.

Genótipos de feijão preto para adaptabilidade, estabilidade e produtividade via modelos mistos para o stado do Rio de Janeiro, Brasil

ABSTRACT: The study of adaptability, stability, and productivity is essential for selecting and recommending superior genotypes. This fact is particularly the case for the introduction of common bean cultivars in Rio de Janeiro, Brazil, whose production is negligible and does not meet the internal demand. Thus, this study estimated genetic parameters and selection gains and undertake a simultaneous selection for adaptability, stability, and productivity in black bean genotypes via mixed models. The investigation was carried out in three municipalities in the state of Rio de Janeiro during three crop years. The trials were set up in a randomized block design with 11 genotypes and three replications. High mean heritability (81%) and selection accuracy (90%), as well as good selection prospects, were observed. Gains between 1.03 and 9.49% were achieved for grain yield. Simultaneous selection was efficient, indicating two black bean lines (CNFP 15290 and CNFP 15361) as the most productive, adaptable, and stable. As such, these lines have the potential to be released as new black bean cultivars for the state of Rio de Janeiro.

Intensive monocropping of bananas decreases the soil acid buffering capacity via ammonia-oxidizing bacteria

Ammonia-oxidizing microorganisms (AOM) are vital for soil nitrogen cycling, nutrient availability, and soil health during sustainable agriculture. Long-term continuous cultivation of bananas and improper chemical fertilization affect the adaptability of AOM; however, the underlying basis for this phenomenon is unclear. This study utilized 16S rRNA gene and metagenomic sequencing techniques to examine soil from banana plantations that were continuously cultivated for 2, 3, 7, 10, 12, and 13 years (Y2, Y3, Y7, Y10, Y12, and Y13, respectively). The results indicated a significant decrease in soil acidity buffering capacity (pHBC) with increasing years of continuous cropping. Furthermore, compared with forest soil (Y0), Y7, Y10, Y12, and Y13 soils exhibited a significantly increased potential nitrification rate (PNR) as well as an abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB), with no significant difference in complete ammonia oxidizers (comammox). Principal component analysis (PCA) further demonstrated marked differences in chemical properties and ammonia-oxidizing microbial community structures between the soils under long-term (Y7, Y10, Y12, Y13) and short-term (Y2, Y3) banana cultivation. In addition, metagenome analysis results indicated that the relative abundance of Nitrososphaera-AOA and Ca. Nitrosocosmicus-AOA as well as Nitrosospira-AOB, Nitrosovibrio-AOB, Nitrosomonas-AOB, and comammox Nitrospira jacus was significantly higher in Y7 and Y13 soils than in Y0 controls. Redundancy analysis (RDA) identified pHBC, CEC, and NH4+ as the primary chemical factor responsible for the differences in AOM microbial communities, whereas random forest analysis revealed that Nitrosospira-AOB significantly contributed to PNR. In summary, long-term continuous banana cultivation primarily stimulates AOB promote soil ammonia oxidation, leading to soil acidification.Graphical

Climate, crops, and postharvest conflict

AbstractI present new evidence of the effects of climate shocks on conflict. Focusing on political violence in Africa, I find that El Niño Southern Oscillation shocks during the crop‐growing season affect harvest‐related conflict in croplands exposed to this climate phenomenon. Specifically, a 1°C warming of sea surface temperature in the tropical Pacific Ocean, a proxy for a moderate‐strength El Niño event, reduces political violence in exposed locations with crop agriculture, relative to other areas, by approximately 3%, during the early postharvest season. This effect attenuates toward zero as the crop year progresses. This effect can reach as much as 15% after a strong El Niño event, such as that of 1997 or 2015, in highly exposed croplands, such as parts of Southern Africa and the Sahel. Conversely, a La Niña event, which is a counterpart of an El Niño event, has the opposite effect and thus increases conflict in the exposed croplands during the early postharvest season. Because these events can be predicted several months in advance, the findings of this research can contribute to creating a platform for early warnings about transitory spatiotemporal shifts in political violence in predominantly agrarian societies.

Variabilidad, tendencia y eventos extremos en los rendimientos agrícolas a nivel de partidos en la provincia de Buenos Aires

Climate variability is the main determinant of fluctuations in the productive and economic results of agriculture. Extreme events are expected to occur with greater frequency and intensity in the future. In this scenario, the effects of climate variability on agricultural production are of special interest. This study analyzes the time series of yields at the county level of the main crops in the province of Buenos Aires, in the period 2000/01-2020/21. The trend and occurrence of extreme values ””of wheat, corn and soybean yields are identified. The frequencies of extreme values ””are related to the phases of the ENSO -El Niño-Southern Oscillation phenomenon, for each crop year. Yields show significant positive trends in 78%, 46% and 30% of the counties for wheat, corn and soybean, respectively. There is a significant relationship between the frequencies of extreme yield values ””and the ENSO phases, this relationship being more important in summer crops. In particular, there is a relative frequency of extremely low or very low yields of 38 and 41%, in second consecutive La Niña crop years, for corn and soybean, respectively. While the frequencies of extremely low or very low yields in neutral or El Niño crop years are between 0% - 3%. Regarding the economic value of production, the differences between obtained vs. expected values, accumulated in the period, are positive values of +3285 and +872 million USD in “El Niño” years for the north and south regions, respectively, and negative values of -3387 and -388 million USD, in “La Niña” years for both regions, respectively. The results provide evidence on the potential value of ENSO-based seasonal forecasts for agriculture. However, it is necessary to deepen the analysis of the effects of ENSO and other seasonal phenomena on yields. It is also necessary more information about the attitudes of the farmers in the Pampas and the different management practices that can be adjusted based on these forecasts.

Genetic Diversity and Gains from Selection for Fruit and Bean Physical Traits from the Conilon Coffee Genotype

Plant breeding of Coffea canephora is based on the characterization and use of the natural genetic variability of the species. Thus, the objective of this study was to quantify the genetic diversity and gains from selection of the fruit and bean physical traits of the C. canephora plant, seeking to understand the relations among the yield components and identify genotypes with superior traits. For this purpose, 42 genotypes were evaluated over two crop years while considering a randomized block design in a factorial arrangement to quantify the effects of genotypes, crop years, and the interaction between these two factors. Coffee fruit samples in the cherry stage were used to evaluate the weights, volumes, and dimensions of the fresh fruit and beans after drying. Genotypic variance prevailed over environmental variance for all of the fruit and bean physical traits of the coffee plants, except for the greatest fruit width (FWG). These associations indicate that the constituent parts of the fruit increased in a manner proportional to an increase in weight. Such associations can facilitate or hinder plant selection. The total gains obtained through the selection indices were similar to those obtained through direct selection for greater bean weights. However, the use of selection indices made it possible to identify clones with more balanced traits.

PRELIMINARY STUDIES ON THE INFLUENCE OF THE CLIMATE ON THE PHENOLOGY OF THE VARIETIES FOR BLACK GRAPEVINES GROWN IN THE BANU MĂRĂCINE VITICULTURAL CENTER

Each wine-growing area is characterized by the presence of a complex of climatic, edaphic and anthropogenic factors, which can influence the moment of the onset of the phenophases, the duration of the phenophases, the quality and quantity of grape production, depending on the genetic characteristics of the varieties, the specific climatic conditions of the crop year and by the applied technology. Starting from these considerations, the present work represents a preliminary stage of a case study regarding the observation of how 3 grape varieties: Cabernet Sauvignon, Merlot and Fetească neagra go through the main phenophases in the climatic conditions specific to the Banu Maracine wine center in the year 2023, as well as the evaluation of the productive results obtained. The study proves to be important in the context of the changes found in the course of the phenophases as a result of the climate changes that have occurred in recent years.

Environmental, energy, and economic (3E) assessment of viticulture systems.

Given the current trends, it seems obvious that temperatures and atmospheric carbon dioxide levels will rise over the coming years. To deal with climate change, a gradual transition to more sustainable viticulture operations is required. It seems necessary to carry out accurate local studies for future projections. The purpose of the current study was to choose the best grape production system in Jowzan Valley, Malayer, Iran. This region was registered by FAO as a Globally Important Agricultural Heritage System (GIAHS) in 2018. This study seeks to answer the question: if climate change has occurred in the Malayer region, which of the traditional and trellis systems is more sustainable from economic, energy, and environmental aspects? The sixth phase of the Coupled Model Intercomparison Project (CMIP6) was used to project the climate parameters of Malayer in the past and the future. The output of climate models based on rainfall, temperature, and wind (as factors influencing grape yield) in the observation period of 1992-2021 (the base period) and forecasting the future period of 2021-2100 under three scenarios (SSP1-26, SSP2-45, and SSP5-85) were obtained. The determination of hotspots in terms of cost, energy, and environment for two production systems was done with the approaches of material and energy flow cost accounting (MFCA) and life cycle assessment (LCA). The results of these two approaches help us know which of the two systems are currently more sustainable in terms of economic, energy, and environmental aspects. Grape production in 1 hectare was chosen as a functional unit (FU). The system boundary included the foreground processes that the farmer was directly involved in managing. Grape data were collected in the crop year of 2021-2022 from the vineyards of Jowzan region. According to results, under SSP1-26, SSP2-45, and SSP5-85 scenarios, the annual mean temperature is expected to rise at rates of 0.27, 0.477, and 0.82°C 10a-1 in the future (2021-2100), respectively. From an economic point of view, labor was recognized as the main input. By changing the system from traditional to trellis, production costs can be expected to be halved. The main hotspot in terms of negative products was the loss of grapes during production or harvesting. Such conditions were also true in terms of energy. From the environmental aspect, on-farm emissions and electricity were identified as hotspots. These effects are greatly reduced in the trellis system compared to the traditional system. In the case of changing the system from traditional to trellis, these effects can be reduced to a reasonable extent by improving the efficiency of irrigation and fertilizer distribution through the irrigation system. According to the results obtained from the climate scenarios as well as the results of the economic, environmental, and energy evaluation of the two production systems, it can be concluded that the use of the trellis system can be more sustainable than the traditional system.

Impact of No Tillage and Low Emission N Fertilization on Durum Wheat Sustainability, Profitability and Quality

Mitigation practices for cereal systems, including conservation agriculture and low emission fertilization, are required to face global challenges of food security and climate change. The combination of these climate-smart approaches was investigated for durum wheat in a dry region of the Mediterranean basin in two crop seasons. The experimental design consisted in two different genotypes, Marco Aurelio (high protein content) and Saragolla (higher adaptability), subjected to no tillage (NT) vs. conventional tillage (CT) and to two fertilization strategies (standard vs. low emission plus an unfertilized control). Different environmental and economic sustainability parameters as well as two different technological and nutritional quality traits were evaluated. Saragolla showed a better environmental adaptability and a higher nitrogen use efficiency, evaluated as partial nutrient balance (+27%), and was associated with a lower protein content (14.5% vs. 15.6%). NT was associated with an improvement in yield (+15%) and quality, i.e., micronutrients (Fe, Zn) and antioxidant capacity (+15%), in the drier crop year. Low emission fertilization did not reduce crop performance and its combination with NT showed a higher economic net return. The combination of the two mitigation practices improved not only environmental and economic sustainability but also the health quality of durum wheat under water limited conditions.

Impact of continuous cropping on tobacco growth, stress resistance, and soil microecological structure

Tobacco fields have been continuously cropped for several years because of the high demand for tobacco leaves and limited land resources. To explore the effects of continuous cropping on tobacco growth and soil microecological community structure, this study compared the agronomic traits and physiological resistance characteristics of tobacco plants grown in noncontinuous cropping soil and soil with different continuous cropping years. High-throughput sequencing technology was used to analyze and predict the microbial community structure and functional gene variation patterns of tobacco soil. The results demonstrated that continuous cropping significantly impacted the average height, leaf area, and stem diameter of tobacco plants, as well as the contents of malondialdehyde, hydrogen peroxide, and glutathione in tobacco leaves that were continuously cropped. The relative abundances of Proteobacteria, Bacteroidetes, and Gemmatimonadetes in tobacco soil decreased with an increase in continuous cropping years, while relative abundance of Acidobacteria increased. The biodiversity index of tobacco soil samples showed a decreasing trend with an increase in continuous cropping years, with the sample with the longest continuous cropping year (33 years) having the lowest biodiversity index. Prediction of the potential functions of soil samples with different continuous cropping years revealed that the Z-scores of each pathway in noncontinuous cropping soil samples ranged from 1.12 to 0.078, while those in 33-year continuous cropping samples decreased from −0.10 to −1.41. Our findings indicate that continuous cropping has negative impacts on soil health and microecology, leading to a reduction in beneficial microbial population and microbial diversity.

The LTAR Cropland Common Experiment at Lower Chesapeake Bay.

The Lower Chesapeake Bay (LCB) Long-Term Agroecosystem Research (LTAR) Common Experiment (CE) located in Beltsville, MD, focuses on research of concern to producers of the major regional crops, which are corn (Zea mays L.), soybean [Glycine max (L.) Merr.], wheat (Triticum aestivum L.), and various forage species. Livestock production in the region includes broiler and laying chickens (Gallus gallus domesticus L.) and dairy and beef cattle (Bos taurus L.). The LCB region is among the most heavily populated in the United States. Urban development pressure is high for both farms and natural areas. The need to restore Chesapeake Bay water quality is a major influence on regional agricultural practices. Conservation practices such as cover cropping, no-till agriculture, and nutrient management planning are more common in the region compared to nationally. However, farmers still face management challenges implementing practices that address water quality and the rise of herbicide-resistant weeds. Researchers at the LCB site recognize the need to protect the Chesapeake and Delaware Bays and maintain farmer profitability. The LCB CE compares a 3-year crop rotation system featuring alternative crop management (cover crop intensification, crop rotation diversification, and integrated weed management [IWM]) with a prevailing 2-year system (no cover crops and no IWM), both under continuous no-tillage, to identify the optimal balance to promote the sustainability of regional cropping systems. The LTAR LCB site provides data-driven tools and solutions to support farmers in the mid-Atlantic region.

Impacts of Harvest Year and Cultivation Location on Off-Flavor Compounds and Functionality of Pea Protein Isolate.

The impact of four different harvest years and two cultivation locations (CLs) of pea seeds on their protein wet fractionation yield, volatile and non-volatile beany flavors, and functionality were investigated. Both harvest years and CLs significantly affected protein recovery, but protein purity was primarily influenced by CLs. Seed age emerged as a dominant factor causing the reduction in linolenic/linoleic acid content and lipoxygenase (LOX) activity which surpassed the effect of harvest years in the seeds but not in their proteins. CL significantly affected fatty acid composition in both seeds and proteins, whereas its effect on LOX activity was discernible only in the proteins. Volatile beany compounds in the proteins were affected by both harvest years and CLs, correlating with their polyunsaturated fatty acid (PUFA) content and LOX activity. Both factors minimally impacted the emulsification capacity of the proteins but imposed a significant effect on their rheological properties. Altogether, the results revealed that seed crop years and especially locations affect pea protein quality, calling for proper adaptation strategies.

Enrichment of Phytopathogen Dominated by Volutella in the Rhizosphere May Be an Important Cause of Continuous Cropping Obstacles in Sweet Potatoes

ABSTRACTObstacles related to the continuous cropping of sweet potatoes (Ipomoea batatas (L.) Lam.) restrict its intensive production. However, the effects of continuous cropping on soil properties and/or the rhizosphere microbial community are largely unclear. In this study, we analyzed changes in rhizosphere soil chemical properties and microbial communities of sweet potatoes across different cultivation years. We observed that the microbial diversity and complexity of the fungal ecological network in rhizosphere soils of sweet potatoes were decreased after 5 years of continuous cropping, with significant enrichment in Sphingobium, Gemmatimonas, Volutella, and Neoidriella. Tuber yield, soil pH, and available potassium (AK) content were significantly reduced after continuous cropping, with the soil microbial community having the highest correlation with pH, AK, and ammonium nitrogen (NH4 +‐N). Specifically, soil pH and AK were positively correlated with Bacillus and Gaiella, and negatively correlated with some plant‐pathogenic fungi (Volutella and Neoidriella), while NH4 +‐N showed the opposite trend. In addition, soil pH, AK, and the relative abundance of Bacillus were positively correlated with tuber yield, while Volutella showed the opposite trend. In summary, the continuous cropping of sweet potatoes negatively affects rhizosphere soil health, resulting in imbalanced soil fertility and an increased abundance of pathogens. These results improve our understanding of factors driving obstacles faced with the continuous cropping of sweet potatoes, enabling future studies and the development of technologies to overcome these obstacles.

The role of the application of nanosilver and humic acid on the physiological and yield traits of corn (Zea Mays L.) under deficit irrigation conditions

Water deficit is the most common abiotic stress and at least 75% of corn fields in Iran are exposed to drought stress during different stages of growth. humic acid (HA) and nanosilver (NS) can help mitigate abiotic stresses in plants; especially drought stress. A field experiment was conducted to study the effect of humic acid and nanosilver on the physiological traits and yield of corn during two crop years. Experimental treatments were including deficit irrigation (100%, 80%, 60% of crop water requirement (CWR)) and nanosilver (0 (NS0), 60 (NS60), 80 (NS80) and 100 (NS100) microliters/liter/ha) and humic acid (control (HA0), 500 (HA500) and 1000 (HA1000) g/ha). The highest amount of chlorophyll a, b and total in 100% CWR+NS60+HA1000 was obtained. The highest amount of proline in 60% CWR + NS60 +HA1000 as well as treatment NS0 +HA1000 were observed. In all irrigation levels, the application of NS100 has reduced chlorophyll a and total. The yield components were affected by HA and nanosilver foliar spraying. The highest grain yield was observed in 100% CWR with the application of NS60 +HA500 at the rate of 10,582 kg/ha. In conditions of 100% CWR, nanosilver concentrations had a positive effect on plant growth and yield, and with increasing stress, high concentrations of nanosilver had a negative effect on growth and yield, but with the combined application of nanosilver and HA, the effect of drought stress decreased, which indicates the positive effect of HA in improving plant growth and yield.

Spring nitrogen and plant growth regulator effects on seed yield of orchardgrass

AbstractOrchardgrass (Dactylis glomerata L.) is an important forage seed crop, but unlike other cool‐season grasses, seed yields have not increased over time. Seed yield increases in orchardgrass may be possible with plant growth regulators (PGRs) such as trinexapac‐ethyl (TE) and chlormequat chloride (CCC). Field trials were conducted at Hyslop Experimental Farm near Corvallis, Oregon, over three crop years (2017–2019) to examine the effects of spring nitrogen (N) and PGRs on seed production characteristics in orchardgrass. Spring N treatments included 0, 112, 157, and 202 kg N ha−1 and PGR applications were timed using the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) scale. Four PGR treatments included an untreated control, 210 g TE ha−1 at BBCH 32, 210 g TE ha−1 at BBCH 51, and 105 g TE ha−1 + 1500 g CCC ha−1 at BBCH 32. An interaction of spring N and PGR increased seed yields in 2 years, while spring N and PGR increased seed yield independently in the other year. The combination of TE and CCC PGRs did not increase seed yield over TE alone. Seed yield increases from spring N were due to an increase in seed number m−2, while increases in seed yield attributable to PGRs were the result of increased seed number m−2 and harvest index. This study suggests that the combination of 112 kg ha−1 spring N and 210 g ha−1 TE PGR is the best practice to maximize seed yield in orchardgrass.

ASSESSMENT OF WHEAT GENOTYPES FOR THEIR LOW NITROGEN USE EFFICIENCY UNDER SEMI-ARID CONDITIONS OF PUNJAB, PAKISTAN

Nitrogen is one of the most important and critical macronutrients needed by plants for their optimal growth and development. The current experimental study was designed to examine the response of wheat variety Akbar-2019 under different nitrogen levels keeping the levels of phosphorus and potassium constant. The study was conducted in Chak No. 169/7.R Fort Abbas, District Bahawalnagar under the supervision of the Department of Soil Fertility (Field) during the crop year 2022-23. The experimental material was comprised of a wheat variety Akbar-2019 and five different treatments of nitrogen consisted of (i) N = 160 kg ha-1 (ii) N = 145 kg ha-1 (iii) N = 131 kg ha-1 (iv) N = 117 kg ha-1 and (v) N = 103 kg ha-1. The experiment was laid out under a randomized complete block design with three replications and 170 m² net plot size par treatment per replication. The results revealed the presence of highly significant variations among nitrogen treatments in wheat variety based on the agronomic and morpho-physiological parameters including flag leaf area, thousand-grain weight, grains per spike, relative water contents, stomatal conductance, net photosynthetic rate, biological yield and gain yield. Furthermore, the results also unveiled that treatments with higher nitrogen dosage produce better results for almost all the study parameters including grain yield. These results were also confirmed through correlation coefficient analysis and bar graph graphical representation based on mean data, where correlation coefficient analysis showed a strong positive correlation of grain yield with studied plant traits except biological yield for which the correlation was positive but non-significant. The results suggest that nitrogen in higher amounts up to a certain level is necessary for obtaining maximum output from wheat crops under semi-arid conditions.

Effect of Winter Sowing and Different Fertilizer Sources on Physiological Parameters and Yield Components of Dragon’s Head (Lallemantia iberica Fisch. & C.A.Mey.)

The effects of autumn sowing and chemical, organic, and biological fertilizer sources were explored on yield components and physiological traits of dragon’s head (Lallemantia iberica Fisch. & C.A.Mey). The study was conducted as a factorial experiment based on a randomized complete block design with three replications in a field experiment in the 2017-2018 crop year. The fertilizer treatments included organic fertilizers (vermicompost, manure, and humic acid), biofertilizer (Thiobacillus mixed with sulfur), chemical fertilizer (macro NPK), and control (no fertilizer). The studied traits included seed yield per ha, harvest index, biological yield per ha, chlorophyll a, chlorophyll b, carotenoid, proline, and dissolved carbohydrate. The results of the comparison of the means revealed that the winter sowing outperformed the spring sowing evidently and increased traits like seed yield per ha, biological yield per ha, and harvest index significantly. The fertilization of the plants in both sowing seasons, especially in the winter sowing, increased seed yield per ha, biological yield per ha, and harvest index so that the vermicompost-fertilized winter-sown plants produced the highest seed yield per ha (0.91 g), whereas the application of manure was related to the highest harvest index in the winter sowing (27.9%). The highest biological yield (8797 kg ha-1) was related to the treatment of Thiobacillus of the winter-sown plants. Proline content was higher in the spring sowing plants, and the control treatment in the spring sowing had the highest proline content (0.120 mg g-1). Concerning dissolved carbohydrates, the spring sowing and the unfertilized plants had the highest content (20.3 mg g-1). On the other hand, chlorophyll a, chlorophyll b, and carotenoid were higher in the treatments of Thiobacillus and vermicompost, which resulted in achieving higher yields due to the increase in photosynthesis rate. According to the results, the winter sowing of the dragon’s head in the Azerbaijan region of Iran and the use of Thiobacillus and vermicompost could be recommended for obtaining plants with optimum quality parameters.

IMPACT OF VARIED AMOUNTS OF NITROGENOUS FERTILIZERS ON GRAIN YIELD AND RELATED AGRO-PHYSIOLOGICAL TRAITS IN SPRING WHEAT (TRITICUM AESTIVUM L.)

The application of nitrogen (N) is a critical factor influencing grain yield and agro-physiological traits in spring wheat (Triticum aestivum L.). This study aimed to evaluate the impact of varied nitrogen levels on grain yield and associated traits under field conditions. The study was conducted in Chak No. 136 / 6.R Haroonabad, District Bahawalnagar under the supervision of the Institute of Soil Fertility (Field) during the crop year 2022-23. A randomized complete block design (RCBD) was used, with five N treatments (160, 145, 131, 117 and 103 kg ha⁻¹) applied across three replicates. Key parameters, including flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield, were measured. The results showed a significant increase in flag leaf area, thousand-grain weight, spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield with increasing nitrogen application, with the highest yield observed at 160 kg ha⁻¹. The results unveiled the presence of highly significant variations among nitrogen treatments in wheat variety based on the agro-physiological parameters including flag leaf area, thousand-grain weight, number of spikelets per spike, number of grains per spike, chlorophyll a, stomatal conductance, net photosynthetic rate, biological yield and gain yield. Furthermore, the results also unveiled that treatments with higher nitrogen dosage produce better results for almost all the study parameters including grain yield. The correlation coefficient analysis also confirmed the results and suggested that any wheat breeding program aimed at improving wheat yield must select its parental genotypes based on traits having the highest correlation with yield i.e., flag leaf area, thousand-grain weight, number of grains per spike, chlorophyll a, stomatal conductance and net photosynthetic rate except the number of spikelets per spike and biological yield for which the correlation was positive but non-significant. The results suggest that nitrogen in higher amounts up to a certain level is necessary for obtaining maximum output from wheat crops under semi-arid conditions.