Agrosystems, Geosciences & Environment最新文献

Environmental changes pose major impacts on the performance of crop genotypes with important implications for crop improvement strategies. Hence, breeders pay attention to the effects of genotype by environment interaction (GEI) to mine genetic resources and select adapted genotypes. Twenty sorghum genotypes selected from a large collection of Ethiopian sorghum landraces and two improved varieties were evaluated using a randomized complete block design with three replications at eight locations representing different environmental conditions in Ethiopia. The study aimed at assessing GEI and identifying stable and high-yielding genotypes of sorghum for grain yield and major agronomic traits. Analysis of variance and additive main effect and multiplicative interaction (AMMI) revealed highly significant (p ≤ 0.001) variance due to genotypes, environments, and GEI among all traits except for days to maturity. Plant height, days to maturity, panicle width, panicle weight, and grain yield were highly affected by environment and GEI, while days to flowering, panicle length, and 1000-grain weight were mainly affected by genotypic variations. The data also suggest the importance of considering GEI in screening for high-yielding and stable sorghum genotypes across environments. Among testing sites, Chawaka, Gute, and Uke were ideal environments for grain yield and Asosa was the most discriminative environment. Three genotypes (ETSL100808, Merera, and ETSL100474) were superior and stable across test environments for grain yield and related traits. Overall, based on mean grain yield and disease reaction, AMMI, GGE (genotype and genotype by environment interaction) biplot, and regression models, ETSL100808 was the most stable, high-yielding, and disease-tolerant sorghum genotype, suggesting its potential both in breeding program, as donor of traits, and for direct release as a variety.

The fundamental ecosystem processes in soil are regulated by microbial communities, and community diversity is implicated by soil environmental conditions. Humic acid (HA) improves soil quality and fertility, stimulating the microbial environment, but the detailed effects remain poorly understood. We investigated the effects of HA rates on soil bacterial diversity, particularly on species richness and community composition in the rhizosphere of corn (Zea mays). Inorganic fertilizer (T2), HA 0.5% (T3), HA 1.0% (T4), HA 1.5% (T5), and HA 2.0% (T6) were applied in soil. Initial soil (O1) and control after harvesting (T1) were included. A total of 3601 operational taxonomic units were captured from the overall sample, and analysis of 16S ribosomal ribonucleic acid amplicon sequencing data indicated that HA did not notably impact species richness. Intriguingly, HA induced changes in bacterial community composition, along with the relative prevalence of specific taxa. Certain associations between soil chemical properties and abundance distribution have been uncovered. Notably, exchangeable Mg²⁺, Ca²⁺, and available phosphorus were strongly related to the relative abundance of bacterial phyla. Furthermore, HA potentially shaped the specific bacterial taxa, as the application of HA at different rates had distinct effects on the member of bacterial abundance of each taxon. These findings enhance our understanding of communities potentially being increased or shifted by HA rate addition in short-term corn cultivation.

Integrated crop-livestock systems (ICLS) bring diversity to agricultural systems, enhancing soil ecosystem services, food production, and environmental sustainability. Resource utilization efficiency practices under semiarid ecoregions include dual systems that grow wheat (Triticum aestivum L.) for both grain and grazing (G) and recently complementary to wheat dual systems, cover crops (CC) for feeding both the soil and cattle during the fallow period. The latter continues to generate interest and there is a paucity of information on associated biochemical cycles. The objective was to evaluate the impact of CC and grazing thereof on soil microbiota structure, diversity, proliferation, and nutrient cycling. Introducing CC to no-till (NT [NTC]) and grazing CC (NTCG [ICLS]), increased total PLFA biomass (TPB) for ungrazed CC (NTC) by 12%, and grazed CC (NTCG [ICLS]) by 20%; total bacteria biomass (TBB) by 10% for NTC and 24% for NTCG; total fungal biomass (TFB) by 9% for NTC and 21% for NTCG. The CC significantly increased Gram (−) bacteria biomass by 17% and 34% for NTC and NTCG, respectively; the CC significantly increased Gram (+) bacteria biomass by 6% and 12% for NTC and NTCG, respectively; and the CC significantly increased arbuscular mycorrhizal fungi by 55% and 89% for NTC and NTCG respectively, compared to NT fallow practice. Significant correlations were observed for NO₃⁻–N, NH₄⁺–N, water-extractable organic nitrogen, total nitrogen, and water-extractable organic carbon with TPB, TBB, and TFB using Haney soil health methods. Based on the measured parameters, the soil health status decreased in the order NTCG > NTC > NT > CT, where NT is the no-till, C is the cover crop, G is the grazing, and CT is the conventional-till. Grazing CC enhanced soil bacterial biomass over CC in solitude.

With grower interest in skip and wide row cotton systems, varietal performance in such systems has become a major question. An experiment was conducted in 2022 and 2023 in Tifton and Midville, GA, evaluating three row arrangements (standard 91-cm row spacing, 2 × 1 skip row, and 183-cm row spacing or wide row) and four commercially available varieties (Stoneville [ST] 5091 Bollgard 3 Xtendflex [B3XF], Phytogen [PHY] 400 Widestrike 3 Roundup Flex Enlist [W3FE], DynaGro [DG] 3799 B3XF, and Deltapine [DP] 1840 B3XF). There were no interactions between variety and row arrangement for any response variable, indicating the best variety for standard row spacings would also be the best variety in alternative row arrangements. Plant populations were reduced 32% and 53% in 2 × 1 skip-row and wide-row systems, respectively, compared to standard row arrangements, which accomplishes the major goal of these systems in reducing seed cost. Boll rot and hard lock were reduced in wide row treatments only, which could benefit cotton growers in the lower Southeast. However, reductions in lint yield were associated with 2 × 1 skip row (all site years) and wide row arrangements (three out of four site-years) compared to the grower standard. Differences among varieties were observed in plant heights, lint yield, and fiber quality, which is to be expected. These results confirm much of the work conducted on skip and wide row cotton systems and indicate that for growers in the lower Southeast to achieve maximum lint yields, standard row arrangements are superior to alternative row arrangements.

This study uses a small unmanned aircraft system equipped with a multispectral sensor to assess various vegetation indices (VIs) for their potential to monitor iron deficiency chlorosis (IDC) in a grain sorghum (Sorghum bicolor L.) crop. IDC is a nutritional disorder that stunts a plants’ growth and causes its leaves to yellow due to an iron deficit. The objective of this project is to find the best VI to detect and monitor IDC. A series of flights were completed over the course of the growing season and processed using Structure-from-Motion photogrammetry to create orthorectified, multispectral reflectance maps in the red, green, red-edge, and near-infrared wavelengths. Ground data collection methods were used to analyze stress, chlorophyll levels, and grain yield, correlating them to the multispectral imagery for ground control and precise crop examination. The reflectance maps and soil-removed reflectance maps were used to calculate 25 VIs whose separability was then calculated using a two-class distance measure, determining which contained the largest separation between the pixels representing IDC and healthy vegetation. The field-acquired data were used to conclude which VIs achieved the best results for the dataset as a whole and at each level of IDC (low, moderate, and severe). It was concluded that the MERIS terrestrial chlorophyll index, normalized difference red-edge, and normalized green (NG) indices achieved the highest amount of separation between plants with IDC and healthy vegetation, with the NG reaching the highest levels of separability for both soil-included and soil-removed VIs.

Shade trees are important in cocoa agroforestry systems; however, they release allelochemicals from various parts that affect understory plants. Unfortunately, information on allelochemicals produced by shade tree bark in cocoa plantation remain scarce. This study investigates the effect of allelochemicals from bark of shade trees on cocoa seedlings growth. The experiment was a 4 × 11 factorial study, and the treatments were four different concentrations from each of the 11 tree species. The treatments were laid out in a completely randomized design with four replicates. Data were collected at 30, 60, 90, 120, and 150 days after treatment applications. The tree species alone and bark extract concentrations alone significantly impacted plant height from 90 to 150 days after application. Albizia ferruginea (Guill. & Perr.) Benth, Celtis mildbraedii Engl., and Triplochiton scleroxylon K. Schum produced the highest cocoa seedling heights. All concentrations also influenced stem diameter of cocoa seedlings. Albizia ferruginea enhanced stem diameter significantly among tree species and the control. Tree species and bark extract concentrations interacted to increase fresh root weights and dry plant biomass. Albizia ferruginea consistently increased dry plant biomass, while C. mildbraedii produced the highest enhancement for fresh roots. All concentrations enhanced plant biomass, with the 75 mg mL⁻¹ concentration consistently producing the highest plant fresh and dry weights. Albizia ferruginea and C. mildbraedii can be potential tree species in the cocoa agroforestry when 2-month-old cocoa seedlings are to be transplanted on the field. Bark extract of 75 mg mL⁻¹ concentration can be used as a growth stimulant on cocoa seedlings.

The global extent of salt-affected agricultural land, 20% of which is deemed gypsiferous, results in billions of dollars of annual economic loss, a serious problem deserving of attention. However, the analysis of gypsiferous saline soils, such as in the irrigated Lower Arkansas River Valley (LARV) of Colorado, can result in an inflated estimation of soil salinity when using the traditional soil saturated paste extract electrical conductivity (EC_e), leading to inaccurate crop yield loss predictions and misguided decisions for remediation. Sparingly soluble gypsum (CaSO₄ $�·$ 2H₂O) in these soils dissolves more readily during laboratory preparation of saturated paste extracts because of excess soil water dilution coupled with sample disturbance. We present a pragmatic linear-regression approach to correct for this phenomenon, calibrated using two adapted methods for correcting EC_e on an individual sample basis. The novel approach used electrical conductivity of pore water samples from saline fields to evaluate the accuracy of the correction methods. The approach was applied on soil samples from two surface-irrigated, saline fields in the LARV, which were mapped using electromagnetic induction data and analysis of covariance linear regression, calibrated for EC_e and EC_e corrected for excess gypsum dissoultion (EC_eg). Average EC_eg values are as much as 26% lower than uncorrected EC_e in gypsum-biased portions of the fields. Estimation of corn salinity hazard in these gypsum-affected areas using EC_eg in lieu of EC_e in a traditional yield response function generated mean relative yield values that are higher by up to 13 percentage points. We discuss lessons learned and suggest enhancements to the techniques.

In the past, several wild plants were widely consumed as food by humans. Dandelion [Taraxacum officinale (L.) Weber ex F.H. Wigg] is a wild species with remarkable nutritional and medicinal properties. Many studies have investigated the chemical components of the plant for human health. Nonetheless, little research has been carried out on the cultivation and related production of this species. With this study, we intend to investigate some cultural practices to start defining an efficient protocol for dandelion cultivation in northern Italy. Two seeding rates (0.14 and 0.55 g m⁻²) and two harvest regimes (when leaves reached a length of 20 cm and 1 week later) were compared. Leaf fresh weight yield was determined at each harvest, and the following morphological parameters were measured: plant height, number of plants per square meter, number of leaves per square meter, leaf area index, number of leaves per plant, leaf weight, and specific leaf weight. The productivity of dandelion was found to be unaffected by the seeding rate, and no significant differences were found between harvest regimes. The delayed harvest regime was only advantageous at the first cut as it allowed for a longer establishment phase, resulting in a higher yield. The nitrate content in the leaves differed between the first two cuts and the third and fourth cuts with both harvest regimes and both sowing rates.

Economic losses due to hailstorms across US corn fields occur every year. Hailstorms result in leaf defoliation, decreasing photosynthetic area and impairing carbon assimilation and crop yield for all corn (Zea mays L.) development stages. However, more attention is often given to stand reductions rather than damage to stems or leaf defoliation. During the 2014 growing season, a natural hail event affected many areas of eastern Nebraska. Twelve affected corn fields were surveyed and included in this study. An injury score scale (1–5) was developed based on various injury and severity levels before the V6 (6-leaf corn growth stage) (six-collared leaves). Scores were assigned to affected fields approximately 10–15 days after the hailstorm. At the end of the growing season, ears were harvested, and grain yield per plant was determined. The highest grain yield (p < 0.05) was recorded with plants that were affected but retained a main stem in good condition, albeit defoliation was present (score 1, lowest damage category). In contrast, when the main stem was cut and the plant had poor regrowth (score 3), yields were reduced by approximately 53% compared to plants with an injury score of 1. A significant negative linear relationship (R² = 0.63, p < 0.01) between injury score and yield was observed (higher injury score from hail events resulted in lower yields). Based on these results, corn yield reduction due to plant injury from hail events before V6 should not be only attributed to stand reductions. Our findings indicate an opportunity to adjust the US evaluation standards for early-season hail damage events in corn fields.

Maize (Zea mays L.) is one of the most important cereal crops in Ethiopia. However, its yield is lower than its potential mainly due to low soil fertility problems caused by continuous cultivation, limited use of organic and inorganic fertilizers, erosion, and leaching. Therefore, this field experiment has been conducted to optimize brewery sludge and blended NPS fertilizer rates to harness the maximum productivity potential of maize in North Mecha District, northwestern Ethiopia. The experiment was designed in a factorial arrangement of three levels of brewery sludge (0, 10, and 20 t ha⁻¹) and four levels of blended NPS fertilizer (0, 50, 100, and 150 kg ha⁻¹) in a randomized complete block design with three replications. The analysis of variance showed that the main effects of the blended NPS fertilizer had significant effects on the ear length, number of kernels per row, stover yield, and 1000-kernel weight. Their interactions also had a significant effect on leaf area, leaf area index, aboveground dry biomass yield, grain yield, plant height, number of ears per plant, number of rows per ear, number of kernels per row, number of kernels per ear, and harvest index. Accordingly, the combined application of 10 t ha⁻¹ brewery sludge and 100 kg ha⁻¹ blended NPS fertilizer resulted in the highest grain yield (9163.4 kg ha⁻¹), net benefit (145,590.1 ETB [Ethiopian Birr] ha⁻¹), and marginal rate of return (3789.30%) of maize. Thus, this treatment can be tentatively recommended for the North Mecha district.