Cereal Crop Production Research Articles

Characterization of soil nematode community structure in semi‐arid dryland barley systems

AbstractSoil nematode community structure and composition can inform crop managers about soil quality. However, few studies have assessed the nematode community under agricultural systems in cool semi‐arid regions such as the U.S. northern Great Plains. We assessed soil nematode community structure of barley (Hordeum vulgare L.) and barley–pea (Pisum sativum L.) cropping systems from 2016 to 2018 in one tilled and two no‐till field experiments under dryland management in central and southwestern Montana. Soils were sampled prior to planting in the spring and following harvest in late summer and nematodes were classified to genus level via microscopy. Both in season moisture stress and overwinter stress explained decline in nematodes in the central Montana no‐till experiments, although consistent impacts of moisture or overwinter stress on nematodes were not detected in the tilled field experiment. Cropping system or sequence did not impact the nematode population (p > .1), but barley yield was positively correlated with larger nematode populations in both no‐till experiments (r > .60). The percentage of fungivores were negatively correlated (r = –.42) to barley yield under tillage. Plant parasitic nematodes were positively correlated (r = .43) to barley yield under tillage. These results suggest that factors which enhance cereal crop growth and productivity rather than crop diversification drive short‐term nematode community dynamics when crop rotations are established in cool semi‐arid regions. Future work is needed to determine if cropping system changes can impact nematode populations after several years in cool semi‐arid regions and, if so, what ecosystem services result from these transformations.

Contribution of the grain size QTL GS3 to yield properties and physiological nitrogen-use efficiency in the large-grain rice cultivar 'Akita 63'.

The development of crop varieties with high nitrogen-use efficiency (NUE) is thought to be important in achieving sustainable cereal crop production. The high yield large-grain rice cultivar Oryza sativa L. ‘Akita 63’ (temperate japonica) has high physiological NUE (PNUE) for grain yield (GY). Our previous study revealed that a large-grain allele of GS3 is present in ‘Akita 63’. Here, we verified the influence of GS3 on the yield properties and PNUE for GY in ‘Akita 63’. The frequency distribution of brown rice length in F2 crosses of ‘Iwate 75’ and ‘Akita 63’ showed a continuous distribution that could be explained by GS3. A near-isogenic line was developed to substitute the GS3 segment of ‘Koshihikari’, which harbours a normal-sized grain allele, in the genetic background of ‘Akita 63’ and the line was designated as Akita63NILGS3-Koshihikari. Compared with Akita63NILGS3-Koshihikari, ‘Akita 63’ exhibited a significantly increased grain length, single brown grain weight and GY, although no significant differences were observed in the nitrogen content and above-ground biomass per unit of cultivated area. These results indicate that the GS3 large-grain allele is a contributing factor to high PNUE for GY in ‘Akita 63’. These findings will facilitate the development of nitrogen-efficient rice varieties.

Increasing photosynthetic productivity of cereal bioenergy crops as affected by the water content in leaves under mycorrhization of the root system

Purpose. To determine photosynthetic productivity of miscanthus gigantheus and switchgrass as affected by leaf water content under mycorrhization of their roots.
 Methods. Field, laboratory, and statistical.
 Results. The obtained results indicate that the use of vesicular-arbuscular mycorrhizal (VAM) preparations Mycofriend (fungus Trichoderma harzianum RIFAI.), Mikovital (fungus Tuber melanosporum VITTAD.), and nitrogen-fixing preparation Florobacillin (Bacillus subtilis Cohn.) helps to increase water content in the leaves of such cereal bioenergy crops as miscanthus gigantheus and switchgrass. In particular, in all vegetation periods, in the treatments with Mycofriend, the water content in miscanthus gigantheus leaves was higher by 11.2–20.1% than in the control, while in switchgrass it was higher by 16.9–20.5% than in the control. In the treatments with Mikovital and Florobacillin, leaf water content ranged in miscanthus from 7.1 to 15.6% and from 5.8 to 11.7%, respectively, and in switchgrass, from 11.6 to 14.7% and from 7.0 to 10.2%, respectively. The photosynthetic productivity of these crops is affected by the water content in the leaves. There is a close correlation between these factors (correlation coefficient 0.95–0.96).
 Conclusions. Root application of biological plant products Mycofriend, Mikovital and Florobacillin improves water content in the leaves of cereal bioenergy crops, such as miscanthus gigantheus and switchgrass, and increases their photosynthetic productivity.

Maize Output Supply Response to Climatic and other Input Variables in Ethiopia

Climate change is among the major challenges to sustainable agricultural production in Ethiopia. Production of cereal crops, especially maize, is very responsive to changes in rainfall and temperature, as climatic parameters influencing productivity. This paper analyzes how climatic and other variables affect the supply of maize in Ethiopia. The data were obtained from secondary sources and cover the period 1981–2018. Data were analyzed using the Autoregressive Distributed Lag (ARDL) approach. The Akaike Information Criterion (AIC), Schwarz Information Criterion (SIC), and Hannan-Quinn Information Criterion (HQ) were used to select the optimum number of lags. In order to detect whether unit root is present in the series, Augmented Dickey-Fuller (ADF) and Philips-Perron (PP) tests were carried out. The presence of long-run equilibrium was found between maize output and temperature, rainfall, and other included variables. The results show that, in both the long and shortrun, all included climatic variables had a negative relationship with maize output supply, although temperature showed statistical insignificance (P>0.10). The result showed that maize crops are highly sensitive to extremes of rainfall – both shortage in the initial growing period and excessin the vegetative and fruiting stages. It was concluded that farmers face climate-related risk due to variations, particularly in rainfall. Therefore, farmers should adapt by using short-duration and climate-tolerant varieties of maize, along with engagement with eco-friendly production systems.

Farming intensity indirectly reduces crop yield through negative effects on agrobiodiversity and key ecological functions

Farming intensity and landscape heterogeneity influence agrobiodiversity and associated ecological functions. The relative contributions of these agroecosystem components to agricultural production remain unclear because of inter-relations and weather-dependant variations. Using a structural equation modelling approach, we estimated direct and indirect contributions of farming intensity (soil management, pesticide use and fertilisation) and landscape heterogeneity (of semi-natural covers and crop mosaic) to cereal crop production, in 54 fields (mostly wheat), in two years (24 and 30 fields). Indirect effects were evaluated through agrobiodiversity (carabid and plant communities) and ecological functions (pollination and pest control). In 2016, farming intensity had the largest direct positive effect on cereal crop yield, followed by agrobiodiversity (74% of the farming intensity impact) and ecological functions. However, the direct benefits of farming intensity were halved due to negative indirect effects, as farming intensity negatively affected within-field biodiversity and ecological functions. Overall, agrobiodiversity and farming intensity had equal net contributions to cereal crop yields, while heterogeneity of the crop mosaic enhanced biodiversity. In 2017, neither higher farming intensity nor agrobiodiversity and ecological functions could lift cereal production, which suffered from unfavourable meteorological conditions. Semi-natural habitats supported agrobiodiversity. Our study suggests that a reduction of farming intensity combined with higher heterogeneity of crop mosaic can enhance the benefits of ecological functions towards crop production. Semi-natural covers seem to play an essential role in the face of climatic events, by supporting agrobiodiversity and the potential resilience of the agroecosystem functioning.

Combined Application of Compost, Zeolite and a Raised Bed Planting Method Alleviate Salinity Stress and Improve Cereal Crop Productivity in Arid Regions

Soil salinity and climate change have a negative impact on global food production and security, especially in arid regions with limited water resources. Despite the importance of planting methods, irrigation, and soil amendments in improving crop yield, their combined impact on saline soil properties and cereal crop yield is unknown. Therefore, the current study investigated the combined effect of soil amendments (i.e., compost, C and zeolite, Z) and planting methods such as raised bed (M1) and conventional (M2), and different fractions of leaching requirements from irrigation water, such as 5% (L1) and 10% (L2), on the soil physio-chemical properties and wheat and maize productivity in an arid region. The combined application of C + Z, L2, and M1 decreased soil salinity (EC) and sodicity (ESP) after wheat production by 37.4 and 28.0%, respectively, and significantly decreased by these factors by 41.0 and 43.0% after a maize growing season. Accordingly, wheat and maize yield increased by 16.0% and 35.0%, respectively under such a combination of treatments, when compared to crops grown on unamended soil, irrigated with lower leaching fraction and planted using conventional methods. This demonstrates the significance of using a combination of organic and inorganic amendments, appropriate leaching requirements and the raised bed planting method as an environmentally friendly approach to reclaiming saline soils and improving cereal crop production, which is required for global food security.

Field Crop Responses and Management Strategies to Mitigate Soil Salinity in Modern Agriculture: A Review

The productivity of cereal crops under salt stress limits sustainable food production and food security. Barley followed by sorghum better adapts to salinity stress, while wheat and maize are moderately adapted. However, rice is a salt-sensitive crop, and its growth and grain yield are significantly impacted by salinity stress. High soil salinity can reduce water uptake, create osmotic stress in plants and, consequently, oxidative stress. Crops have evolved different tolerance mechanisms, particularly cereals, to mitigate the stressful conditions, i.e., effluxing excessive sodium (Na+) or compartmentalizing Na+ to vacuoles. Likewise, plants activate an antioxidant defense system to detoxify apoplastic cell wall acidification and reactive oxygen species (ROS). Understanding the response of field crops to salinity stress, including their resistance mechanisms, can help breed adapted varieties with high productivity under unfavourable environmental factors. In contrast, the primary stages of seed germination are more critical to osmotic stress than the vegetative stages. However, salinity stress at the reproductive stage can also decrease crop productivity. Biotechnology approaches are being used to accelerate the development of salt-adapted crops. In addition, hormones and osmolytes application can mitigate the toxicity impact of salts in cereal crops. Therefore, we review the salinity on cereal crops physiology and production, the management strategies to cope with the harmful negative effect on cereal crops physiology and production of salt stress.

The Response of Iranian Melon (Cucumis melo L.) Accessions to 2,4-D Drift.

One of the most widely used auxinic herbicides in southern Iran’s cereal crop fields is 2,4-D; however, the concurrent growing season of off-season melons in this region potentially leads to herbicide drift from cereal fields to the melon fields. To study the response of some Iranian wild melon accessions to three simulated drift rates of 2,4-D, including 112.1, 11.2, and 3.7 g ae ha−1, a field experiment was conducted during 2019 and 2020 growing seasons. It was found that by increasing the herbicide rate from 3.7 to 112.1 g ae ha−1, the level of visual injury increased in all accessions. However, significant variation in herbicide tolerance was observed among different melon accessions. The MEL-R1 was the most tolerant accession with only 20% injury, while MEL-D8 displayed very high injury rate (ca. 90%) as assessed at 6 weeks after treatment during 2019. The accession MEL-S3 was the most tolerant to 2,4-D drift rates (20% injury) at 6 weeks after treatment during 2020. There was no significant difference between the accessions MEL-R1 and MEL-S3 in terms of their response to 2,4-D treatment during both years of the study, as these accessions fully recovered from injury over 6 weeks after herbicide treatment. In addition, only these two accessions were able to produce yield after the application of 2,4-D at the highest rate tested (112.1 g ae ha−1). Therefore, the melon accessions MEL-R1 and MEL-S3 could be recommended for cultivation and even for breeding programs in order to develop 2,4-D-tolerant commercial cultivars in regions where this herbicide is commonly used in cereal crop production adjacent to the melon fields.

Statistical model for evaluation of the impact of climatic conditions on the crops production: the regional aspects

The work examines the statistical model for evaluation of the impact of climatic conditions on the crops production in Ukraine. The conducted content analysis of academic literary sources enables to arrive at conclusion that the majority of Ukrainian scholars consider changes in climatic zones of Ukraine a positive trend for crops production. It must be emphasized, nonetheless, that the increase in natural heat provision for crops production against the backdrop of a significant reduction in average annual precipitation considerably diminishes the sizes of cultivated and harvested areas, gross yield and overall crop yield of basic crops and perennial plantings. To perform calculations on key statistical indicators of crops production the following tools have been employed: methods of analysis of absolute, relative and average values; methods of elaboration and study of groupings; methods of analysis of the structure of statistical populations; methods of cross-impact analysis of indicators; methods of trend studies. The analysis concerned the dynamics of change in statistical indicators of crops production in Kherson oblast over the period of 1990–2019: gross yield of cereal and leguminous crops; total harvesting area of cereal and leguminous crops; wheat yields; cereal and leguminous crops production per capita. Periods of diverse degrees of occurrence of atmospheric precipitation in Kherson oblast according to the level of liquid saturation have been grouped: dry, medium, humid. It has been proved that winter wheat yields are affected by the following factors: size of the cultivation area and average annual precipitation. It is established that the digitalization of the agriculture contributes to the decrease in pressure on land and water resources, provision of conditions for “clean”, sustainable and eco-friendly agricultural products, increase in gross yield of crops, provision of conditions for efficient use of resources, capability of Big Data processing. Prospects for further research lie in elaboration of a multi-factor non-linear modeling of winter wheat yield with account for the factors of humus and soil pH; average annual atmospheric temperature, etc.

Short phases of tropical forage legumes increase production of subsequent cereal crops in the seasonally dry tropics of eastern Indonesia

In temperate systems, it is well known that forage legumes can improve both nitrogen (N) supply and yields of subsequent cereal crops. While this is assumed to be true in tropical systems, it is less well tested, particularly in smallholder settings where forage is often cut and removed from the field. This paper confirms the potential of short phases of tropical forage legumes to provide N to subsequent crops in seasonally dry tropical farming systems. Across five experiments, maize and rice grain yields increased by up to 80 % after 4−8 month rotations of forage legumes, but the benefits were smaller when legume growth was reduced, biomass was removed for forage, or the yield potential of cereal crops was lower. We found that the additional N cycling from legumes can last for at least 2 years, although the benefit diminishes with time. When all legume material was retained as mulch, the estimated additional N provided to subsequent no-till maize crops was the equivalent of 9−15 kg urea-N per tonne of above-ground legume biomass produced but fell to 1.5−3 kg urea-N/t if forage was removed. After shoot removal, more legume N cycled to a subsequent rice crop (equivalent of 11–13 kg urea-N/t of legume biomass) than to a no-till maize crop, presumably because more below-ground material mineralised. Of the legumes tested, Clitoria ternatea grew best across a variety of environments and use patterns and provided the largest yield benefits to subsequent crops. This research demonstrates the potential to integrate short phases of tropical herbaceous forage legumes into smallholder crop-livestock systems in the seasonally dry tropics, and, in doing so, improve or maintain staple grain crop production and household food self-sufficiency.

Meta-Analysis Approach to Measure the Effect of Integrated Nutrient Management on Crop Performance, Microbial Activity, and Carbon Stocks in Indian Soils

Cereal crop production gains under conventional agricultural systems in India have been declining in recent years because of inadequate management practices, creating a considerable concern. These activities were shown to deplete soil organic matter stocks, resulting in a decrease in microbial activity and soil organic carbon (SOC) content. Moreover, even with minimal use of organic sources in cultivated land, soil carbon status deteriorated, particularly in subtropical climates. Integrated nutrient management (INM), a modified farming method, has the potential to effectively utilize organic and inorganic resources, to improve the quality of soils and crops, and making farming more economically viable and sustainable. The aim of this study was to use meta-analysis to quantify the effects of INM on crop production, soil carbon, and microbial activity in Indian soils. During the years 1989–2018, data from various research studies in India, mainly on nutrient management in rice and wheat crops, were collected. Meta-Win 2.1 software was used to analyze the results, and significance was determined at p < 0.05. The results showed that the yield of rice and wheat was 1.4 and 4.9% more in INM than that in 100% NPK (N: nitrogen, P: phosphorous, and K: potassium), and that respective yields were comparatively higher in loamy soils (2.8%) and clayey soils (1.0%). The INM treatment increased SOC and microbial biomass carbon (MBC), resulting in improved overall soil quality. The SOC stock was increased by 23.8% in rice, 15.1% in wheat, 25.3% in loamy soils, and 14.4% in clayey soils in INM over 100% NPK. Microbial quotient (MQ) data showed significant trends between different management systems in both soil types, for example, INM > 100% NPK > No NPK. Due to more soil cracking and reduced aggregate stability in the rice field (greater short-term soil structural changes), the SOC stock loss in rice was higher than that in wheat. The CO2 equivalent emissions were 7.9 Mg ha−1 higher in no NPK (control) than in 100% NPK, and 16.4 Mg ha−1 higher in control than in INM. In other words, INM increased soil carbon sequestration by 2.3 Mg ha−1 as compared to using 100% NPK. Overall, the findings of this study show that INM could be a viable farming system mode in India for improving crop production, increasing soil carbon sequestration, and improving microbial activity while remaining economically and environmentally sustainable.

Can Tanzania\u2019s adaptation measures prevent future maize yield decline? A simulation study from Singida region

Cereal crop production in sub-Saharan Africa has not achieved the much-needed increase in yields to foster economic development and food security. Maize yields in the region’s semi-arid agroecosystems are constrained by highly variable rainfall, which may be worsened by climate change. Thus, the Tanzanian government has prioritized agriculture as an adaptation sector in its intended nationally determined contribution, and crop management adjustments as a key investment area in its Agricultural Sector Development Programme. In this study, we investigated how future changes in maize yields under different climate scenarios can be countered by regional adjusted crop management and cultivar adaptation strategies. A crop model was used to simulate maize yields in the Singida region of Tanzania for the baseline period 1980–2012 and under three future climate projections for 2020–2060 and 2061–2099. Adaptation strategies to improve yields were full irrigation, deficit irrigation, mulch and nitrogen addition and another cultivar. According to our model results, increase in temperature is the main driver of future maize yield decline. Increased respiration and phenological development were associated with lower maize yields of 16% in 2020–2060 and 20% in 2061–2099 compared to the 1980–2012 baseline. Surprisingly, none of the management strategies significantly improved yields; however, a different maize variety that was tested as an alternative coping strategy performed better. This study suggests that investment in accessibility of improved varieties and investigation of maize traits that have the potential to perform well in a warmer future are better suited for sustaining maize production in the semi-arid region than adjustments in crop management.

Rainfall seasonality and timing: implications for cereal crop production in Ethiopia

Rainfall seasonality and timing are key climatic features affecting crop yield in rainfed agriculture (RFA). We evaluated the dynamics of temporal rainfall attributes – the strength of seasonality, the date of onset, cessation, and duration of the rainy season – over RFA areas across Ethiopia for the period 1981-2010 and explored their impacts on cereal crop production (including maize, teff, sorghum, wheat, barley, millet, oats and rice) between 1995 and 2010. First, we quantified the rainfall seasonality using an entropy-based seasonality index, defined the onset and cessation dates of rainy seasons, computed the rainy season duration, and analyzed their interannual variability and trends. Second, we correlated de-trended total cereal production during the Meher (i.e., long rainy) season (April to September) with the anomalies of the temporal rainfall attributes, and we used a univariate linear regression model to estimate the influence of changes in these attributes on crop production. We show that RFA areas in northern Ethiopia are characterized by a highly seasonal and unimodal rainfall regime. The southern parts of the RFA areas are characterized by less seasonal rainfall of bimodal and erratic nature. Cereal crop production during the Meher season, especially in teff and maize-dominated regions, is found to be correlated to both the onset (median ρ=-0.32 and -0.37, respectively) and duration (ρ=0.34 and 0.19) of the rainy season in the unimodal rainfall regime, whereas it is correlated with the rainfall seasonality (ρ=0.21) in regions with a bimodal rainfall. We estimate that on average over RFA areas, a late-onset and shorter rainy season lead to ∼1.5% and 1.1% crop production losses per pentad (5-day period), respectively.

English

Although Ethiopia is endowed with diverse agro-ecologies suitable for cereal production, the success of the production relies more on climate condition. Therefore, this study is initiated to analyze the trends of; cereal crops production area and productivity in Ethiopia. Data of meher season cereal crops productivity (qt/ha) and area of production (ha) were collected from Central statistical Agency (CSA) of Ethiopia. Trend test was carried out using the non-parametric Mann-Kendall’s trend test packaged in XLstat. The result of this study indicated that the area of cereal crops production for teff, wheat, maize, finger millet and rice showed significant increasing trend. But only sorghum production area indicated non-significant increasing trend. Moreover, Barley indicated non-significant decreasing trend. Moreover, the productivity of all cereal crops indicated significant increasing trend, except rice which decreased non-significantly. Productivity of Barley significantly increased despite non- significant decreasing production area. Similarly, productivity of Oat’s significantly increased despite significant decreasing production area; while the productivity of the rest crops (teff, wheat, maize, finger millet and rice) increased significantly with significant increasing trends of production area. However, differently from the others: Productivity of sorghum significantly increased despite non-significantly increasing area of sorghum production. Key words: Cereal crops, trend Analysis, area of production and productivity.

Analysis of El Niño Southern Oscillation and its impact on rainfall distribution and productivity of selected cereal crops in Kembata Alaba Tembaro zone

El Niño Southern Oscillation could likely distort the hydro climatological processes and adversely affect agricultural production at various magnitudes. This study explored the manifestations of ENSO-induced rainfall variability and its impact on selected cereal crops in Kembata Alaba Tembaro Zones of southern Ethiopia. Accordingly, precipitation, temperature, crop, and Sea Surface Temperature (SST) data were collected from the National Meteorology Agency of Ethiopia, and the National Oceanic and Atmospheric Administration (NOAA). Rainfall variability was analyzed using the Coefficient of Variation and various anomaly indices. Spatial and temporal relationships between SST and yield of selected crops were established using the person correlation method. Mann-Kendal trend test was also used for trend analysis. The results revealed a statically significant (P < 0.05) decreasing trend and highly variable spring and summer rainfall. Global SSTs strongly influence both summer and spring rainfalls. El Niño and La Niña events were shown to influence the local rainfall distribution and crop production at varying magnitude over different spaces and times. The yield reduction due to ENSO increases from wheat, barley, maize to Sorghum, respectively, while Enset (ventricosum) was found to be less influenced by ENSO-caused rainfall variability. This implies that sorghum and maize crops are more sensitive to El Niño and La Niña events in the study area compared to the other crops considered in this study. The conformity of Enset yield with rainfall variability could be attributed to its tolerance to moisture stress. From the results, one can conclude that the overall cereal crop productivity was adversely, but differentially, affected by ENSO-induced climate variability.

Broadening farmer options through legume rotational and intercrop diversity in maize-based cropping systems of central Malawi

• Evaluated diverse legume-maize systems in a 4-year, multi-site, on-farm study. • Pigeonpea-maize rotation had the most biomass, ideal for amending infertile soils. • In hot and dry environments, groundnut increased maize yield in a subsequent year. • Pigeonpea biomass was key to high N fixation yet suppressed by intercropping. Smallholder farmers across southern Africa have limited access to adequate quantities of inorganic fertilizers, and this limits crop productivity. Integration of legumes such as groundnut ( Arachis hypogaea L.) and pigeonpea ( Cajanus cajan L.) improve soil fertility and subsequent cereal crop productivity through biological nitrogen fixation (BNF), and high-quality residues. The objective of this four-year, multi-site, on-farm study in Malawi was to evaluate diverse legume systems, quantify crop production, economic viability, and total N accumulation in groundnut and pigeonpea. The study involved six research sites with different agricultural productivity potential based on precipitation, elevation, and temperature; to evaluate crop performance by environment. The six cropping systems evaluated were sole pigeonpea or sole groundnut rotated with maize ( Zea mays L.) (PP-MZ and GN-MZ), groundnut/pigeonpea intercrop rotated with maize (GNPP-MZ), maize/pigeonpea intercrop (MZPP), continuous unfertilized maize (MZ-MZ), and fertilized maize (MZ+F). Total N accumulated by cropping system was in the order GNPP > PP > MZPP > GN at 180, 130, 103 and 87 kg N/ha respectively. In the groundnut/pigeonpea intercrop, despite a reduction of pigeonpea biomass, pigeonpea was still the main driver for N cycling in the systems. The average percentage of N derived from BNF (BNF-N%) from all plant components and across sites was 66% for groundnut and 52% for pigeonpea. Average maize grain yield for response years when rotated with legumes was 4.82, 3.25, and 2.16 Mg/ha for sites with high (Linthipe), medium (Kandeu), and low (Golomoti) agricultural productivity potential. System performance in terms of gross margins ranged from $1145 (pigeonpea-maize rotation) to $1407/ha (groundnut/pigeonpea-maize rotation). The pigeonpea-maize rotation produced the most biomass but had modest economic and agronomic returns during the legume phase. This study highlighted that, for hot and dry environments, groundnut was the most effective species at increasing maize yield in a subsequent year. The groundnut/pigeonpea-maize rotation system met multiple goals including high pigeonpea biomass, profitable groundnut grain, and high maize yields during the rotational year. This system is recommended for ecological intensification, as it provided an economically feasible means to enhance BNF on smallholder farms, while ensuring multiple grain harvest goals in different environmental contexts.

Bottom-up re-estimations of greenhouse gas and atmospheric pollutants derived from straw burning of three cereal crops production in China based on a national questionnaire.

Crop straw open burning is considered as an important source of greenhouse gas and atmospheric pollutants emissions, which affects global climate change and regional air quality. However, due to the limitation of data availability, the current emission estimation of greenhouse gas and atmospheric pollutants from crop straw open burning remains uncertain based on the bottom-up method. Therefore, we re-estimate the greenhouse gas and atmospheric pollutants from crop straw open burning at the county level based on a national questionnaire and the up-to-data emission factors. Results showed that emissions of CO2, CH4, N2O, PM10, PM2.5, NMVOC, NH3, NOx, SO2, CO, BC, and OC from open straw burning are 69250.8 Gg, 242.9 Gg, 4.2 Gg, 771.0 Gg, 539.7 Gg, 498.2 Gg, 34.7 Gg, 200.4 Gg, 24.8 Gg, 3426.5 Gg, 63.0 Gg, and 278.5 Gg, respectively, which were lower than those of previous studies. Maize was the largest contribution, followed by wheat, rice. Hotspots for greenhouse gas and atmospheric pollutants from straw burning are mainly distributed in the 54 counties of northeast China, accounting for 20% of total emissions on average. However, the high emission of maize, wheat, and rice are mainly located at the counties of north China, northeast China, and middle-lower Yangtze River region, respectively. This study not only provides the targeted counties that need decrease further the straw open burning, but also improves the precision of emission estimation that benefits air quality modeling.

Genetic and Molecular Factors Determining Grain Weight in Rice.

Grain weight is one of the major factors determining single plant yield production of rice and other cereal crops. Research has begun to reveal the regulatory mechanisms underlying grain weight as well as grain size, highlighting the importance of this research for plant molecular biology. The developmental trait of grain weight is affected by multiple molecular and genetic aspects that lead to dynamic changes in cell division, expansion and differentiation. Additionally, several important biological pathways contribute to grain weight, such as ubiquitination, phytohormones, G-proteins, photosynthesis, epigenetic modifications and microRNAs. Our review integrates early and more recent findings, and provides future perspectives for how a more complete understanding of grain weight can optimize strategies for improving yield production. It is surprising that the acquired wealth of knowledge has not revealed more insights into the underlying molecular mechanisms. To accelerating molecular breeding of rice and other cereals is becoming an emergent and critical task for agronomists. Lastly, we highlighted the importance of leveraging gene editing technologies as well as structural studies for future rice breeding applications.

Determinants of sorghum crop commercialization the case of Southwest Ethiopia

Smallholders farming are responsible for a large proportion of Ethiopian food production. Sorghum is one of drought-tolerant crop which plays a crucial role in improving household food security level and source of income. However, there are different constraints which hinder the production and commercialization of cereal crops. Therefore, this study was aimed at identifying the determinants of sorghum producers’ commercialization in Kaffa, Sheka, and Bench Sheko Zones Southwest, Ethiopia. Data for the study were collected from both primary and secondary sources. The primary data were generated by a household survey using a pre-tested semi-structured questionnaire. Purposive and three-stage sampling techniques were used to draw 543 farmers. The data were analyzed using descriptive statistics and an econometric model. The Tobit model results indicated that sex of household head, educational level of household head, land under sorghum production, non/off-farm income, sorghum quantity produced, credit amount receive, and oxen were found to influences significantly the degree of commercialization. Policy implications drawn from the study findings include enhancing the productivity of land, strengthening supportive institutions and improving infrastructural facilities. Supporting female-headed households through different policy initiatives and interventions can improve their market participation decisions. Strengthening supportive institutions such as credit access and extension contact would motivate farm households to improve market participation.

Striga (Witchweed) Threats to Cereal Crops Production and Its Management: A Review

Striga (witchweed) is one of the most successful parasitic weeds of cereal crops in Africa. It is ‘a poor farmer’s problem’ as there is a near perfect ecological overlap between areas of Striga infestation and where hunger prevails. It is originated in Semien hills of Ethiopia and the Nubian hills of Sudan and later expanded in about 42 African countries. Striga hermonthica, Striga asiatica, Striga gesnerioides, and Striga aspera constitute the greatest economic threat to cereal crops’ yield losses. They are obligate root parasites causing growth inhibition and yield losses of 20-100% in maize, rice, sorghum, pearl millet, finger millet, sugar cane and cowpea. Cultural practices such as long-term rotational cultivation of cereal crops with legume crops unaffected by the parasite is effective in managing the weed. Besides, biological control by use of parasitic fungi ( Fusarium oxysporum and Vesicular arbuscular mycorrhiza) play a role in managing the weed. In addition, chemical control with imidazolinone herbicide, ethylene gas, dicamba and 2,4-D are effective in managing striga in cereal crops in extreme cases. Integrated use of striga resistant crop varieties with water conservation practices, soil fertility amendment and use of parasitic fungi ( Fusarium oxysporum and Vesicular arbuscular mycorrhiza) is effective in control, economically safe, socially acceptable and environmentally friendly than a single control measure. Therefore, the promising integrated striga management practices should be highly promoted. Moreover, host and Striga species specific integrated Striga management should be designed. Keywords: Haustoria; Obligate parasite; Root parasite; Strigolactones; Witchweed DOI: 10.7176/ALST/88-02 Publication date: July 31 st 2021