Soybean Cultivation Research Articles

Soybean cultivation in Russia under modern conditions

The article presents an analysis of the current state of soybean production in the Russian Federation. It is shown that the production of this valuable high-protein oilseed crop over the previous years has made a huge breakthrough in conquering the market and increasing its share in the country’s total agricultural production. In Russia, in 2023, a record was set for the gross soybean production in history, with a total grain of 6.8 million tons. At the same time, the production leader also changed: from the traditional Far East, where soybeans have been cultivated for more than 100 years, to the Central Federal District, which has achieved the largest gross soybean yields in the country – about 3.0 million tons. Production growth is realized not only through extensive development paths, but also through increasing crop productivity. In 2023, the average yield in the country was 1.92 t/ha, which is also a historical maximum. It should be noted that in increasing productivity, the direction has been taken, according to the Food Security Doctrine, to increase to 75% the share of seeds of domestic varieties in the total volume by 2030, and for this there are all the necessary resources.

Use of zoohumus extracts in soybean cultivation under regulated agroecosystem conditions

A model experiment was conducted in the laboratory conditions of the climate chamber to study the effect of liquid extract of black soldier fly zoohumus prepared in different ways on the growth rates and germination of seeds of the early ripening soybean variety EN Argenta. The zoohumus suspension was used in all variants at a dose of 0.2% (2000 ppm). As an additional background, a complex fertilizer containing the necessary plant nutrients in the form of various mineral salts was added. Analysis of the experimental data showed that the highest percentage of plant germination was recorded in the variant with the introduced aqueous suspension of zoohumus without centrifugation and without sterilization, and amounted to 94%. Against the background of pure organic matter, an increase in shoot biomass by an average of 22% was recorded. However, here the variant with sterilization, but without centrifugation of the zoohumus suspension, stood out. Against the background of the organomineral environment, the weight and height of the plants were higher, but stagnation in growth was noted, probably due to oversaturation in the feeding regime and the formation of chelate complexes of prolonged absorption. Thus, an aqueous suspension of zoohumus obtained by sterilization without additional centrifugation is the best way to prepare samples of raw materials for further use in sterile experiments. Centrifugation reduces the amount of enzymes and nutritional compounds, which negatively affects the quality of the suspension, and additional sterilization releases an additional amount of low-molecular compounds into the environment, which can feed microorganisms.

Pesticide residues in tropical agricultural soils: distribution, seasonality, and earthworm ecological risk

Soil contamination by pesticide residues is associated with agricultural intensification in tropical regions and endangers human health and the environment. A mixture of pesticide residues and their degradation products persist in agricultural soils and represent a risk to soil organisms. In this study, we aimed to investigate the concentration and distribution of organochlorine (OC) and organophosphate (OP) pesticide residues in agricultural soils where the industrial cultivation of maize and soybeans is intensively carried out, at three depths (0-5, 5-15, and 15-30 cm) and during two seasons (rainy and dry). Likewise, we performed the ecological risk assessment of those found pesticide residues on two earthworm species, Eisena fetida, and Aporrectoda calagionsa. We calculated the Toxicity-Exposure Ratio (TER) using Predicted no Effect Concentrations (PNEC) and measured concentrations in soils, for identifying the risk of pesticide residues separately. The Risk Quotient (RQ) method was used to evaluate the ecological risk of pesticide residue mixtures in soils from each cropping system. Endrin ketone and dieldrin were the pesticide residues with the highest frequency of detection. The highest concentration in the study was found in a soil sample from maize crops in the dry season at 15-30 cm depth (2917 ng/g). The pesticide mixture from soil samples belonging to maize (0-5 cm) and soybean (5-15 cm) crops in dry season posed the highest ecological risk for A. caliginosa with 100 %, and a maximum RQ of 82.2. Endrin ketone is the OC that contributed most to the overall toxicity of the pesticide mixture in soil samples from maize crop and dieldrin in soil samples from soybean crop. Among OP, disulfoton contributed most to RQsite in soybean crop and methyl parathion in maize crop. Results pointed out the need to apply alternatives to remediate obsolete pesticide residues and restrict the use of methyl parathion and disulfoton in maize and soybean crops, to reduce the ecological risk that represent for earthworms.

Personnel correlates of farmers about dibbling method of soybean cultivation

Personnel correlates of farmers about dibbling method of soybean cultivation

EFFECT OF PRE-EMERGENT HERBICIDES ON SOYBEAN CROPS GROWN IN ROTATION WITH SUGARCANE

The need for sugarcane field reform has driven the expansion of soybean cultivation in rotation with sugarcane. Weeds are one of the main reasons for this reform, requiring specific management in rotation. The use of pre-emergence herbicides in soybean is a viable option, but its effectiveness in sandy soils requires further study. In this experiment, we evaluated the performance of pre-emergence herbicides on sugarcane straw, focusing on the control of Digitaria horizontalis. We conducted a field experiment with 11 treatments and four replications, applying herbicides immediately after soybean sowing. All herbicides, except diclosulam, provided efficient control of D. horizontalis, with over 80% control in all evaluated periods. The clomazone+sulfentrazone association showed the highest residual effect, keeping the area clean for up to 21 days after application. Weed-free control resulted in productivity equivalent to 66% of the maximum obtained. The use of cell division inhibitors allowed soybean cultivation to grow without weed competition. We conclude that the use of pre-emergence herbicides in soybean under sugarcane straw resulted in productivity gains due to effective D. horizontalis control. Poaceae plants may have a higher competitive capacity with crops compared to other families; therefore, even with few plants per square meter, species like D. horizontalis can reduce crop productivity. The use of cell division inhibitor molecules, either alone or combined with PROTOX inhibitors, allowed the soybean crop to remain free of weed competition.

Alternatives for controlling insect pests in crops of agronomic interest using Bacillus thuringiensis and Brevibacillus laterosporus

The bacteria Bacillus subtilis and Bacillus thuringiensis have been the main target of research for a long time, making it necessary to identify new microorganisms capable of being used and that accompany the rapid development of biotechnology. The work aims to evaluate the efficiency of isolates of B. thuringiensis and B. laterosporus in controlling caterpillars in crops of agronomic interest. Experiments were conducted with the cultivation of Cotton, Sugarcane, Citrus, Bean, Cabbage, Maize, Soybean and Wheat in different environments to evaluate the efficiency of B. thuringiensis and B. laterosporus isolates in controlling caterpillars. Analysis of variance took place at 5% probability using the F test. Subsequently, the Scott-Knott grouping of means was used at 5% probability. The synergistic use of chemical and biological insecticides promotes satisfactory rates of pest control in crops of agronomic interest. Isolates of B. thuringiensis and B. laterosporus are efficient in controlling caterpillars when applied at the highest dosages tested.

Transnational Governance of Soybean Land Use in South America: A Polycentric Approach

Abstract The expansion of soybean cultivation in South America has created substantial economic prosperity but has also raised a series of unsustainable land-use issues. Considering the telecoupling system (a system of socio-ecological interactions between distant places) between South America and its soybean trade partners, transnational governance could play an important role in addressing these issues. To achieve effective governance of this specific telecoupling system, this study applies a polycentric approach to improve the existing transnational governance and identify more suitable governance arrangements. This study first explores the telecoupling system and the existing transnational governance system of soybean land use in South America. It then compares the existing governance system with the polycentric approach to examine the gaps between them. Based on these analyses, suggestions for improving the governance system are provided, including increasing the involvement of major governance centres, improving public-private partnerships, and establishing a knowledge-sharing platform.

Long-term experiments to identify response patterns of available soil nitrogen, rice, and soybeans to rice straw compost in a paddy-upland rotation field in Akita, Japan

ABSTRACT Compost application can enhance soil fertility and is consequently presumed to increase crop production in Japan’s paddy-upland rotation fields. This study aimed to evaluate the effects of rice straw compost (RSC) application on available soil nitrogen (Av-N) levels and rice and soybean plants in a paddy-upland rotation field using data obtained from a long-term field experiment. Data collected between 2005 and 2020 were analyzed from a long-term paddy rice – upland soybean rotation field. The experimental design employed a split-plot arrangement, with RSC application (with and without RSC) representing the whole plot, N fertilizer application (no nitrogen vs. standard fertilizer) representing the split-plot, and years representing the replication factor. The datasets included eight years of rice and soybean cultivation, and the chemical properties of postharvest soil spanned 16 years. The data was analyzed via analysis of variance. Applying RSC increased the Av-N concentration significantly by 63%–67%. The RSC application significantly increased the N concentration in rice shoots at the mature stage by 8%–12% but decreased it in soybean shoots after the seed emergence stage by 4%–8%. Consequently, the rice yield displayed clear responses to RSC application, whereas the soybean yield did not. The lack of soybean yield response might be due to an inhibitory effect of the Av-N gain attributable to the RSC application on biological nitrogen fixation. While applying compost can enhance Av-N content as well as rice productivity in paddy-upland rotation fields, its impact on soybean productivity requires careful evaluation.

The Impact of Winter Cover Crops on Soil Nematode Communities and Food Web Stability in Corn and Soybean Cultivation.

There is increasing adoption of winter cover crops (WCCs) in corn and soybean production in Canada, primarily to reduce erosion and increase soil organic matter content. WCCs have the potential to influence nematode communities by increasing free-living nematodes and decreasing plant-parasitic nematodes or vice versa. However, the mechanism by which WCCs change nematode community assemblages still remains a key question in soil food web ecology. We tested the hypothesis that the long-term use of rye (Secale cereale), barley (Hordeum vulgare) and oat (Avena sativa) as monocultures or mixtures promotes nematode communities and improves overall soil health conditions compared to winter fallow. The results from this study revealed that the use of WCCs generally promoted a higher abundance and diversity of nematode communities, whereas plant parasitic nematodes were the most abundant in winter fallow. Moreover, the mixtures of WCCs had more similar nematode communities compared to rye alone and winter fallow. The structure and enrichment indices were higher with WCCs, indicating higher nutrient cycling and soil suppressiveness, which are signs of healthy soil conditions. Furthermore, WCCs significantly reduced the populations of root lesion nematode Pratylenchus, although their numbers recovered and increased during the main crop stages. Additionally, mixtures of WCCs promoted the highest abundance of the stunt nematode Tylenchorhynchus, whereas winter fallow had a higher abundance of the spiral nematode Helicotylenchus during the fallow period and the main crop stages. The results show that the long-term use of cover crops can have a positive impact on nematode communities and the soil food web, but these changes depend on the type of WCCs and how they are used.

The productivity of selected soybean cultivars grown using various cultivation methods

Soybean is an important legume crop globally due to its rich protein, oil content, and functional components. The purpose of this study was to evaluate the yield of selected soybean cultivars depending on cultivation methods. The three-year field experiment, conducted from 2018 to 2020 at the Agricultural Experimental Station in Kępa-Puławy, Osiny farm (Institute of Soil Science and Plant Cultivation – State Research Institute in Puławy), investigated these variations. The first experimental factor was the soil cultivation method: A – conventional tillage, B – reduced tillage, and C – strip tillage. The second variable was soybean cultivar: ‘Aldana’ and ‘Merlin’. The soybean cultivars were selected for their differing maturity rates: ‘Aldana’ (000) is an early cultivar, while ‘Merlin’ (000++) semi-late cultivar. The field experiment utilised a split-plot design on Luvisol soil with sandy loam texture, belonging to a good rye complex, class IIIb–IVa, and was replicated four times. The study showed that the productivity (seed and protein yield) of the ‘Merlin’ cultivar grown in the central-eastern part of Poland was approximately 8% higher than that of the ‘Aldana’ cultivar. The cultivation method had a relatively minor influence on soybean yield, the content of selected nutrients, morphological features, and elements of the yield structure. The soil in strip-tillage method was more compact than the soil cultivated with a plough. After harvesting soybeans at a depth of 30, and 40 cm, the compactness of soil in strip-tillage or with reduced tillage was much lower than in spring, highlighting a positive effect of soybean cultivation on loosening the arable layer.

A robust method for mapping soybean by phenological aligning of Sentinel-2 time series

Soybean is an important crop for food and animal feed. Production and area both continue to increase and expand into new areas and countries. Spatially explicit information on soybean cultivation is essential to crop monitoring, production estimation, and national accounting systems. However, its cultivation in diverse climate conditions, landscapes, and agricultural systems poses challenges to accurately map soybean across different regions and years. We propose an innovative soybean mapping method combining phenological alignment with machine learning (named here RF-DTW), which can be applied to diverse geographies and years by aligning phenological shifts and using distinctive features from Sentinel-2 time-series. The method first uses the dynamic time warping (DTW) algorithm to align the growing season between pixels across different sites. Then, based on the harmonized time-series, a set of distinctive features was identified and used to build random forest (RF) models to classify soybean across ten globally distributed sites and multiple years. Results show that the green chlorophyll vegetation index (GCVI), greenness and water content composite index (GWCCI), normalized difference senescent vegetation index (NDSVI), red edge position (REP), and short-wave infrared bands are important inputs for distinguishing soybean from other crops. Spectral-phenological features, particularly the curve slope metrics of GCVI and GWCCI during the peak to late growing season, rank as the most important features for mapping soybean. RF-DTW demonstrates good generalizability across ten study sites, achieving an overall accuracy (OA) of 0.92 and an F1-score of 0.84. F1-scores for eight out of ten sites ranged between 0.82 and 0.98, outperforming a benchmark method, although they were lower (F1-score < 0.60) for the two sites in Sub-Saharan Africa. Additionally, RF-DTW performs robustly when transferred to untrained regions and years, with most cases showing an F1-score higher than 0.70. Our proposed method, as a combination of phenological alignment and machine learning, can be used to map soybean accurately and efficiently across different regions and years, to provide crucial information for understanding the rapid dynamics of soybean cultivation and its global-scale impacts.

Germination of soybean seeds after low-temperature storage and its dependence on weather and climate conditions in the places of reproduction of accessions

Background. Soybean (Glycine max (L.) Merr.) is a microbiotic whose seeds quickly lose germination in uncontrolled conditions at room temperatures. This determines the need to preserve accessions in special conditions. Low temperature storage (LTS) allows to maintain high seed germination ability, but not for all accessions. Therefore, it is relevant to assess the results of LTS at the VIR Genebank and to make an attempt to determine the best geographical conditions for growing plants and harvesting seeds that will be subjected to LTS. Materials and methods. The work was carried out on 312 soybean accessions from the VIR collection, originating from almost the entire area of soybean cultivation. The accessions used in the research were reproduced at three VIR experiment stations (ES), namely Adler ES, Kuban ES (Krasnodar Territory) and the Far East ES (Primorsky Territory). The seeds were harvested in 1999 to 2017 and stored in sealed foil laminated bags at –10°C from 2002 to 2021. The accessions were removed from LTS and germination assessed in 2022. Results. At the beginning of LTS, seed germination (Gi) ranged from 12 to 100% (averaging 79.1%), while that after LTS (Gr) ranged from 1 to 97% (57.8% on average). The retention of germination ability was expressed as the germination index (GI = Gr / Gi), which ranged from 0.02 to 1.73 (an average of 0.72). All the indicators of germination in the range of up to 20 years of LTS were not associated with the duration of LTS and with the number of years before LTS (0.5-4 years in our research). The climatic conditions characteristic of the place of reproduction had a significant impact on Gi and Gr, but not on GI. The average Gi of seeds obtained at the Adler ES and Kuban ES did not differ significantly (77.4% and 75.7%), while that of seeds harvested at the Far East ES was significantly higher (84.0%). Gr of the accessions from the Far East ES (64.3%) was also greater than that of accessions from the Kuban ES (52.2%) and Adler ES (57.2%). The excessively high sum of temperatures above 10°C (recorded in some years at all stations) reduced Gi, Gr but had little effect on GI. The highest values of Gi, Gr, and GI were demonstrated by the accessions maturing in 101-120 days. Additionally drying of the most late-ripening accessions (later than 140 days) in sheaves under an awning yielded seeds with high germination ability and good LTS tolerance. Conclusion. The seeds from different places of reproduction of accessions differed in germination before and after LTS, and, on an average, the highest values were demonstrated by the seeds harvested at the Far East ES, where the temperature regime is closer to the optimal one for soybeans. The seed germination index showed relative independence from the conditions of reproduction of accessions, including the climate and weather conditions, as well as the initial germination ability and LTS duration.

Leaf-stem diseases of soybean on varieties of diferent ripenity groups in the conditions of the Amur region

The Amur region is the main producer of soybeans in the Russian Federation, where one of the significant phytosanitary problems of soybean cultivation technologies is leaf and stem infections. The susceptibility of soybeans to diseases varies greatly depending on weather conditions, used agricultural technology and the resistance of cultivated varieties. Since the soybean varieties, cultivated in the region, have significant differences in early maturity, it remains relevant to monitor leaf and stem infections and identify the degree of their development depending on the length of the crop growing season and the year conditions. The purpose of the study was to assess the influence of soybean variety by maturity groups and year conditions on the incidence of leaf-stem infections. Research was carried out in 2022 and 2023 in the Tambov district of the Amur region on 32 soybean varieties of domestic and foreign selection, belonging to 3 ripeness groups: early ripening, mid-ripening and late ripening. A phytopathological examination of soybean crops revealed Septoria blight (Septoria glycines T. Hemmi. Syn.), Cercospora blight (Cercospora sojina Hara), Ascochyta blight (Ascochyta sojaecola Abramoff. Syn.), downy mildew (Peronospora manshurica (Naum.) Syd. Syn.), purple Cercospora blight (Cercospora kikuchii (Matsuet Tomoyasu) Yardn) and angular bacterial spot. According to the indicator of disease incidence on soybean varieties of three ripeness groups, it was revealed that the incidence of downy mildew significantly, at the level of 90 %, depended on the variety ripeness group: mid-, and especially late-ripening varieties, were affected by the disease in both years an order of magnitude more strongly than early-ripening varieties. No significant influence of soybean varieties maturity groups on other infections was detected after the use of the fungicide, while analysis of variance according to the two-factor experiment scheme showed a significant influence of year weather conditions on the diseases incidence: Cercospora blight – at the level of 75.7 %, Cercospora purple blight – 77.1 %, Ascochyta blight – 98.5%. Both the ripeness group of soybean varieties and the year conditions influenced the bacteriosis incidence: the disease was more pronounced on early-ripening varieties, which were more populated by mites, the vectors of the disease pathogen, and was noted only in 2023. Analysis of variance according to the two-factor experiment scheme did not reveal a significant influence of varieties and year conditions on the incidence of Septoria blight, which indicates significant adaptations of the pathogen to weather factors and the physiology of plants from different ripeness groups, as well as the stable effectiveness of fungicidal treatment of soybean crops against Septoria blight.

Insights into management and physiological determinants of lowest pod height in soybean

AbstractHarvest losses caused by the low height of the lowest pods (LPH) are a significant issue in soybean cultivation. Minimizing these losses requires identifying management, physiological, and agronomic factors that interactively modulate LPH. Four studies were conducted to examine the relationships among soybean LPH, node and internode features, and light quality under different management practices. These practices included population density (19, 31, and 43 plants m−2) and row width (equidistant, 25, 51, and 76 cm), relative maturity (maturity group [MG] 0.8, MG 2.1, and MG 2.8), mulch color (gray bare soil, red mulch, and white mulch), and timing of stand reduction (V1, R3, R4, and R5 growth stages). An increase in population density from 19 to 43 plants m−2 led to an average increase in LPH of 28%, from 11.9 to 15.3 cm. LPH was not influenced by row width. Later maturing cultivars demonstrated the highest potential for enhancing LPH, with late AG2802 having a higher LPH (18.8 cm) than early AG0803 (12.4 cm). Data indicated that the elongation of internodes 10, 11, and 12, along with changes in the red to far‐red light ratio beneath the canopy, plays a pivotal role in determining the location of the lowest pods. Moreover, LPH is established around the R3 growth stage. Nevertheless, further investigations are warranted to gain a better understanding of how these parameters, individually and collectively, influence LPH in soybean.

Integrated pest management of soybean emerging pests in Brazil and United States: a review

Soybean cultivation is crucial for meeting global demand for vegetable oil and protein, with Brazil being the largest global producer, followed by the United States. However, intensifying soja production has led to the emergence of new pests, such as whitefly, thrips, and leaf miners, which cause damage to plants and reduce crop productivity. The integrated pest management approach is essential for sustainable pest control, minimizing pesticide use, and maintaining ecological balance. However, further research is needed on emerging pests and their management strategies.

Cost-effectiveness analysis of weed management treatments in soybean cultivation

Cost-effectiveness analysis of weed management treatments in soybean cultivation

Assessment of soybean productivity and its changing factors in Japan based on the production cost statistics

Soybean (Glycine max [L.] Merr.) yields have remained below 2.0 t ha–1 for over 30 years in Asian countries, indicating long-term stagnation in productivity and production technology. This study aimed to measure the total factor productivity (TFP) of soybean production in Japan and to assess the factors affecting TFP and yield. The Färe–Primont index of TFP was measured for two agroclimatic regions using soybean production cost statistics from 1987 to 2015 to analyze the regression of TFP and yield with per-farm land size, time trends, and production-related input variables. The TFP increased by 1.5–2.4% annually in the two regions, despite an annual decrease of 0.7% in country’s average yield. The TFP in the subarctic Hokkaido region improved by 9–15% due to the land-size increase and progress of time, i.e., technological progress, during the period. While in the temperate main-island region, a 14% TFP increase induced by increased land size was largely offset by the time–progress effect (–11%), i.e., technological retrogression. Similar time–progress effects observed on yield indicated that technological changes occurred, with respect to cultivation methods. The TFP–improving land-size increase adversely resulted in a 9% yield decrease in the main-island region accounting for 85% of soybean cultivation area in Japan. The results further showed that TFP improved by saving production inputs, such as fertilizer, per unit area in both regions, and the yield rose with increased inputs in seed, agrochemicals, and rental services, depending on the region. This study revealed continual soybean TFP improvements across Japan due to land-size increases and input saving in addition to the regionally biased progress in cultivation technologies. The implications of the results are discussed from the perspective of improving TFP and yield while increasing the per-farm land size.

Optimizing an Ultisol of marginal land for soybean cultivation through inorganic fertilizer substitution with Tithonia compost and biochar ameliorant

Soybean has a strategic role as a food commodity in Jambi, Indonesia, but until now, it has still not been self-sufficient. There is still an opportunity to increase soybean productivity in Jambi by 35-49.6% by optimizing the use of marginal, dominated by Ultisol, which has low inherent soil fertility. One of the efforts that can be made to improve soil fertility for cultivating soybean plants in Jambi is to utilize compost and biochar as soil ameliorants to substitute for inorganic fertilizer. This study aimed to assess the effect of compost and biochar ameliorant as substitutes for inorganic fertilizer on the growth and yield of soybean plants grown on an Ultisol of Jambi. The experiment was arranged in a simple randomized block design with the combination of the percentage of inorganic fertilizer with compost and biochar ameliorant (100+0, 75+25, 50+50, 25+75, and 0+100) as the treatment factors. The observed variables were plant height, number of branches, plant nitrogen content, rate of symbiotically fixed nitrogen, weight of 100 seeds, and yield. The results showed that providing compost and biochar ameliorants can replace the role of inorganic fertilizer, and providing 100% compost and biochar ameliorant and a combination of 25% inorganic fertilizer and 75% compost biochar ameliorant can provide the highest growth and yield in soybean plants planted in Ultisol dry land.

Resistance of Bt and Non-Bt Soybean Cultivars Adapted to Novel Growing Regions of Brazil to Chrysodeixis includens and Spodoptera frugiperda.

Soybean is a highly valuable commodity crop for Brazil's economy. However, it faces significant threats from the attack of a complex of lepidopteran pests, particularly Chrysodeixis includens (Walker) and Spodoptera frugiperda (J. E. Smith). These pests have been managed primarily using transgenic Bt soybeans, but limited knowledge exists about the resistance levels of Bt and non-Bt cultivars adapted to novel soybean-growing areas in Brazil, such as the Minas Gerais state. This study evaluated the resistance levels of Bt and non-Bt soybean cultivars to C. includens and S. frugiperda, and whether the Bt cultivars can differentially affect these pests across larval stages. No-choice bioassays were conducted using Bt (NS6010 IPRO and P97R50 IPRO) and non-Bt soybeans (UFLA 6301 RR, P96R90 RR, and ANsc 80111 RR) at V4-stage in the laboratory with neonate (24 h) and third-instar larvae. Larvae were fed leaf discs in Petri dishes, recording the mortality, leaf consumption, and weight gain after 7 days. There was high mortality of C. includens neonates on the Bt cultivars, but this trend was not observed for older larvae. For S. frugiperda neonates, there was high mortality on the Bt cultivar NS 6010 IPRO and non-Bt cultivar UFLA 6301 RR, but only the former was effective for older larvae. Although the Bt cultivars did not kill the third instars, antinutritional effects were found, such that leaf tissue consumed was not converted to larval weight gain. These findings are important for defining regional strategies of integrated and resistance management of C. includens and S. frugiperda in expanding regions of soybean cultivation in Brazil.

Rationality of soybean farmers: the findings from rainfed field agroecosystems

Purpose. This research aims to examine the factors that influence the rationality and income of soybean farmers, especially in rain fed field agroecosystems. Methodology / approach. The research was designed quantitatively with a type of survey on 263 soybean farmers from a total population of 768 farmers spread across Jatiwaras and Pancatengah subdistricts, Tasikmalaya Regency, which is one of the centres for soybean development in West Java, Indonesia. The determination of the farmer sample was carried out proportionally randomly using the Slovin formula with an error rate of 5 %. The data analysed is primary data obtained directly from farmers using a questionnaire with a Likert scale consisting of 5 answer choices. The analytical tool used is Structural Equation Model (SEM) with AMOS to determine the influence between variables. Results. The research results show that: (1) Farmer characteristics have a significant positive relationship with farmer motivation. These characteristics are a strong driving force to increase their motivation in soybean farming to be even better in an effort to increase their income; (2) Farmer characteristics have a significant positive effect on farmer rationality. The older the age, the higher the education, and the greater the burden of responsibility borne by the farmers’ family, the more rational they consider soybean cultivation to be, which means that they will be more cautious in growing soybeans to minimise the risk of losses they may incur; (3) Farmer motivation has a significant positive effect on farmer rationality. The stronger farmers’ motivation in soybeans farming, the more rational it makes them in thinking about farming as well as possible; (4) Farmer rationality has a significant positive effect on income. The more rational the thinking of farmers in soybean farming, in the sense that they can effectively use social networks, efficiently grow soybeans and adopt technology, the more they can increase production, which ultimately increases income. Originality / scientific novelty. This study focuses more on the rationality of smallholder farmers in Indonesia, who have many structural disadvantages, such as limited land ownership, average age of farmers, low education level and many family responsibilities, which are constraints to soybean farming; how smallholder farmers are related to motivation in soybean farming and whether this farmers’ rationality can increase their income, while several previous studies only discussed farmers’ rationality without considering socioeconomic factors, especially smallholder farmers. Practical value / implications. This research provides evidence that there is a relationship between farmer characteristics and motivation which has a significant effect on farmer rationality so that in the end it can increase income. The results of this research have implications for government policies in efforts to increase farmers’ income by increasing their capacity through intensive and sustainable agricultural extension activities. The existence of more intensive and sustainable agricultural extension activities can increase the knowledge and insight of small farmers in soybean farming, which in turn can motivate farmers to think and act more rationally so that they can better optimise all the resources they have.