Base Saturation Levels Research Articles

Biometric Parameters and Yield Components of Wheat (Triticum aestivum) as a Function of Lime and Phosphogypsum Reapplication

ABSTRACT The effects of lime and phosphogypsum (GY) on wheat (Triticum aestivum) nutrition are well documented. However, little is known about the influence of these soil amendments on biometric parameters or yield components. This study investigated the effects of lime and GY on wheat crops grown at cation base saturation (BS) levels of 44%, 70%, and 90%, achieved by surface application or soil incorporation of lime. Two additional treatments were included: surface liming to 70% combined with a standard rate of GY (3.71 Mg ha−1) or twice the recommended GY rate (7.42 Mg ha−1). The experiment was conducted during two crop seasons in Southern Brazil. The treatments did not influence dry biomass partitioning between spikes, stems, and leaves and total. In one season, liming increased flag leaf area, which was strongly associated with grain yield. Regardless of the rate, application method, and combined use of GY, liming increased the number of grains per spike in both seasons, which was the variable that most influenced wheat yield. Liming also increased spike length and the number of spikelets per spike in the 2018 season. No benefits were seen when lime was applied by soil incorporation, BS was raised to 90%, or liming was combined with GY application. The results showed a positive effect of liming on wheat yield components that are associated with grain yield.

Impacts of Varying Sowing Dates on the Profitability and Production of Cultivars of Pigeonpea (Cajanus cajan L. Mill sp.)

At the experimental farm of the College of Agriculture, Badnapur, VNMKV, Parbhani, a suitable range of field experiments were done during the kharif season, with an optimal time of sowing. The experiment was carried out using five varieties in the sub plot, V1-BSMR-736, V2-BSMR-853, V3-BDN-711, V4-BDN-708, and V5-Vipula, and four sowing dates in the main plot, D1: (15 th June), D2: (30 th June), D3: (15 th July), and D4: (30th July). The soil had a medium-black color, a clayey texture, a high base saturation level, an alkaline reaction, and a higher concentration of total soluble salts. It also had low levels of nitrogen and phosphorus and high levels of potassium and lime. The dibbling method of sowing was used. According to the experiment's results, sowing of pigeonpea on June 15 th was the best date to achieve greater yield metrics, specifically number of pods per plant, pod weight plant-1 (g), grain weight plant-1 (g), and test weight (g). in addition to economic indicators including GMR (119080 Rs ha-1), NMR (96573 Rs ha-1), and B:C (5.29), in addition to harvest index (HI), biological yield (kg ha-1) and seed yield (kg ha-1). Comparatively speaking to the other kinds, the pigeonpea variety BSMR-736 was shown to be very prolific.

Species assemblages and their drivers differ between trees and lianas in a seasonal evergreen forest in Thailand

AbstractDespite a long tradition in ecology of studying tree species assembly and its potential drivers in tropical forest communities, little information exists with respect to lianas (woody climbers), the second most abundant life form of woody plants in tropical forests. Lianas influence forest diversity and stability and provide critical resources for forest fauna. Using a unique dataset of a 30‐ha plot in Thailand, where tree and liana individuals were fully mapped, we investigated the degree to which local species assemblages of trees and lianas of different size classes (i.e., seedlings, established individuals, and large individuals) are related to local environmental conditions. We asked (1) What are the spatial patterns and environmental drivers of local tree and liana species assemblages? (2) How do such patterns and drivers differ among size classes? (3) Which species associate with these assemblages? Local assemblages of established trees showed substantial structuring by environmental variables, whereas we found only weakly structured assemblages of tree seedlings, large trees, and lianas of all size classes. Our results indicated that the biotic and abiotic drivers of local species assemblages differed strongly between tree and liana communities and across size classes. Species assemblages of trees were mainly driven by soil nutrients, leading to patchy assemblages associated with high base saturation (Alfisols) and assemblages associated with lower levels of base saturation and higher aluminum (Ultisols), whereas tree seedling assemblages were only weakly structured by riparian zones. In contrast, species assemblages of established and large lianas were primarily associated with forest canopy structure, separating low‐canopy forests from high‐canopy forests, whereas soil nutrients were the only factors associated with liana seedling assemblages. The weak environmental structuring of tree seedlings and large trees suggests that other mechanisms, such as stochastic disturbances, competition for space, or animal seed dispersal, may play an important role in structuring tree communities in this seasonal tropical forest. The weak patterns observed in liana communities across all life stages raise questions about the underlying mechanisms of liana community assembly, and further research should focus on liana niches, their dispersal mechanisms, and host tree relations.

Nickel iron mining slag and soil acidity correction

Soil acidity is one of the limiting factors of agricultural production most commonly reported in oxidic soils, such as Oxisols often found in the Brazilian Cerrado regions for example. The dredging is the most efficient management practice in the correction of soil acidity and increase of base saturation levels. The nickel iron mining scora is a residue that has relevant amounts of magnesium silicate, and may have neutralization capacity of soil acidity. Therefore, the objective of this work was to value the potential of magnesium silicate as a soil acidity corrective. The experimental design used was completely randomized, arranged in a 2x5x5 factorial scheme with twelve replications, where the 1st factor consisted of two hatching dates, 30 and 60 days, the 2nd factor consisted of five doses of mining slag: 0, 90, 120, 150 and 180 Mg ha-1, and the 3rd factor consisted of five doses of dolomític limestone: 0, 90, 120, 150 and 180 Mg ha-1. The mining slag did not present soil pH neutralization power under the evaluated conditions. However, it presented potential for neutralization under conditions of lower granulometry and greater solubilization.

Seasonal quality and statistical assessment of physicochemical properties and base saturation of Hadejia-Nguru wetland soils, Northwest/Eastern Nigeria

Abstract The evaluation of Hadejia-Nguru wetland soils was carried out for two consecutive dry seasons. Standard analytical techniques were adopted to analyze the samples and statistical models were used to assess the spatial and temporal distribution of the parameters selected. The average pH values of the soil samples were mostly alkaline, and all the measured values were also within the approved standards. Experimental results revealed a significantly positive correlation between Ca and Mg for both seasons as indicated by the p-values and a high coefficient of determination (R2) for both metals with cation exchange capacity (CEC) values as the predictors. The regression analysis showed that the changes in CEC and pH levels in the soil were dependent on changes in Ca and Mg content of the soil. The data obtained showed that the increase in pH is directly proportional to the CEC and base saturation of the soils. A higher percentage of Ca than other cations (Mg, K and Na) was observed from the base saturation of the soils. The pH, base saturation, and CEC levels in the soils are suitable for most crops grown in the area, which has the potential to support a wide range of crops with further exploration.

Effects of applying lime and phosphogypsum in soybean and wheat nutrition

This study aimed to assess the nutritional status of soybean and wheat and the relationship with grain yield and biometric components after lime and phosphogypsum (GY) reapplication. Treatments consisted of two lime application methods, surface liming and incorporated liming, to different levels of base saturation (BS) (44, 70, and 90%), in addition to surface liming to 70% BS associated with a standard dose (70GY1) or double dose (70GY2) of GY. Treatments were applied in 2012 and reapplied in 2016. The results refer to the 2018/2019 soybean season and the 2019 wheat season. Lime + GY treatment increased leaf area, plant height, leaf dry matter, and stem dry matter in soybean but had no effect on specific leaf area (235.4 cm2 g−1), stem diameter (6.08 mm), number of pods per plant (71.7), grain number per plant (165), or thousand grain weight (117 g). Liming to 90% BS reduced leaf manganese contents in both crops and leaf iron content in soybean. GY application improved the calcium status of both crops and the sulfur status of soybean. However, 70GY2 reduced leaf magnesium contents in soybean and wheat. Soil tillage without lime reduced wheat yield by 12% compared with no-till. Soybean yield correlated positively with leaf nitrogen (0.79), leaf phosphorus (0.91), leaf area (0.62), and thousand grain weight (0.65), whereas wheat yield correlated with leaf phosphorus (0.83), calcium (0.75), and sulfur (0.74). For improved soybean and wheat performance, it is preferable to apply lime and GY to the soil surface (70GY1), permanently maintaining no-till practices.

Effects of Fertilization Types and Base Saturation on the Growth and Water Productivity in Panicum maximum cv. BRS Zuri

Fertilization management is essential for forage production. However, excessive use of synthetic fertilizers causes environmental imbalances. An alternative to reduce these effects is to seek alternative fertilizers, such as wood ash produced from agro-industrial waste, when integrated with appropriate base saturation management. This study aims to compare the effects of fertilization with wood ash (WA), organomineral (OM), and mineral (M) fertilizers associated with different levels of base saturation on the growth and water productivity of Panicum maximum cv. BRS Zuri. The experiment was conducted in a greenhouse, using a randomized block design in a 3 × 3 factorial arrangement. The treatments consisted of three types of fertilization (WA, OM and M) and three levels of base saturation (0, 25%, and 50%). Leaf area, chlorophyll index, shoot dry mass and root dry mass, water consumption, and water productivity of Zuri grass were evaluated. The results showed significant increases in leaf area, with values of up to 4564.5 cm2.pot−1 and a chlorophyll index of up to 36.2 units. In addition, the dry mass of the aerial part reached up to 46.7 g.pot−1, and the dry mass of the roots reached 21.7 g.pot−1 with the use of OM fertilizers. These values represent an increase of between 43.1% and 69.6% compared to the values of conventional fertilizers. In addition, water productivity reached 4.9 g.L−1 with WA-based fertilizers, an increase of around 39% compared to the values of mineral fertilizers.

Identification of alkaline amendment sources (slash and burn versus marling) for cereal crops grown in the North of France: A multiple isotope approach (87Sr/86Sr, δ44/40Ca, δ88/86Sr)

Early farmers used at least two types of agrarian amendments that could raise pH and base saturation levels to allow the cultivation of cereals: marling and plant ash. Ash can be input in many different ways: felling and burning in place, transferring plant material from wastelands and spreading the ash, charring sod or peat blocks, burning stubble after harvest. Marling includes all the practices of amending limestone, from marl to chalky limestone composed of 99% CaCO3. In order to understand the evolution of these agricultural practices, it is important to identify which of the two techniques was used to amend cereal crops in the past. In order to test the potential of δ44/40Ca-δ88/86Sr-87Sr/86Sr multiple isotope approach for archaeological samples, we first applied the technique to currently grown crops, amended either with marl or with ash from freshly-cut and burned trees. We found that this approach makes it possible to discriminate cereal grains amended either by marling (less radiogenic Sr) or with tree ash (more radiogenic Sr). We also identified a positive correlation between stable Ca and Sr isotope values, suggesting that the Ca and Sr came from similar sources and had undergone similar mass-dependent isotopic fractionation mechanisms. Consequently, we later on mainly focused on stable and radiogenic Sr isotopes. Stable Sr isotope fractionation was also observed between different locations, different organs of a given cereal species and between different cereal types, but also within the same cereal species or the number of grains studied for a given locality, pointing to biological fractionation combined with source variation.

Characterization and Mapping of Soil-Landscape for Site-Specific Soil Management in Ayiba Watershed, Northern Highlands of Ethiopia

The characterization of soil landscapes is becoming increasingly important for making decisions regarding site-specific agriculture systems and soil management. This study was initiated for the purpose of identifying landscape-scale spatial soil variation using a toposequence model so that site-specific fertilization could be achieved. According to the finding, the soils were shallow to very deep in depth, moderately acidic to moderately alkaline in soil reaction, nonsaline in salinity, and clay to sandy loam in texture. The soils were found very low to low levels in most soil nutrients, very low to very high levels of base saturation, and deficient in zinc but have adequate levels of iron, copper, and manganese. The soil exchange complex was mainly dominated by Ca and Mg where the order of occurrence was Ca > mg > K > Na. The CEC values were in high to very high range. Following the field survey and soil analytical results, five main reference soil groups of the World Soil Resource Base—Leptosols (56%), Luvisols (8.5%), Fluvisols (14.4%), Vertisols (13%), and Cambisol (8.2%)—were identified and mapped. Leptosols cover the largest landmass of the watershed and mostly found at the summit and hill back slopes. On the other hand, Luvisols, Fluvisols, Vertisols, and Cambisols were found on the middle and foot slopes. According to the findings, the variation in soil source indicating that topography is the primary pedogenic element in the formation of the soil in the watershed that was under research. Therefore, having local-scale-specific soil information can assist the site-specific application of soil nutrients and amendments based on spatial variability which is tailored to the soil requirements.

Soilscapes and geoenvironments at Stansbury Peninsula, Nelson Island, maritime Antarctica

Considering that the extreme variation in Antarctica’s climate has important effects on soil properties and distribution, characterizing and mapping surface landforms in ice-free areas is strategic. We aimed to evaluate the pedogenetic processes, as well as classify and map the different types of soils at Stansbury Peninsula (ST), Nelson Island. In order to stratify the whole environment area of the Peninsula, we used the geosystems’ approach, identifying the landscape unit of geoenvironment. We mapped geoenvironments and soils, performing physical–chemical and mineralogical characterizations. Our results suggest that compared to other islands in the South Shetlands, the active layer at Stansbury is thin, so that it is more susceptible to climate change, representing a Key monitoring site for climate change studies. The northwestern area of Stansbury Peninsula is the preferential area for marine birds, mammals nesting and resting places. Hence, higher values of nutrients are recorded in their soils. The climate at ST is harsh due to strong northwest polar winds, which promote widespread wind ablation, erosion and contribute to physical weathering, with a high prevalence of periglacial processes under wet conditions, which is typical of this zone of South Shetlands areas, exposed to the Drake passage. Soils at ST are predominantly skeletal, gravelly, with little organic matter and little fauna activity, poor vegetation cover, and high levels of base saturation suggesting limited weathering of volcanic rocks. Soils display a strong characteristic of physical weathering due freezing and thawing process, resulting in typical patterned ground (cryoturbation forming Cryosols), under active periglacial processes. The unique proglacial and periglacial geoenvironments of Stansbury are influenced by melting water and widespread snow banks, under wet polar oceanic climate condition.

POPULAÇÃO DE NEMATOIDES EM CAFEEIRO ADUBADO COM COMPOSTO ORGÂNICO

INTRODUCTION: The use of organic compost to increase organic matter has been a great ally of the rural producer, since it is a practice of easy access, financially viable and ecologically sustainable. Thus, understanding the influence of organic composts on the incidence of nematodes in the soil, consequently, can help reduce the damage caused by these organisms. OBJECTIVE: Influence of organic compost fertilization on nematode population in soil cultivated with coffee trees. METHODS: A randomized block design was used in the experiment, with five treatments (doses of organic compost, 0, 2.5, 5, 7.5 and 10 t ha-1), divided into four blocks, totaling twenty experimental units. The soils had already been corrected with limestone application at doses of 0, 1, 2, 3, and 4 t ha-1. The dose of organic compost application was inversely proportional to the dose of lime application. RESULTS: The results showed a significant increase in calcium, potassium, base saturation and base sum levels. CONCLUSION: The organic matter content does not interfere in the nematode population.

Thermal requirements and agrometeorological modeling of cotton growth under soil fertility levels

The objective was to quantify the thermal requirements and model the growth of cotton as a function of air temperature and degree-days, under levels of soil saturation and potassium fertilization, grown in a protected environment, in Bom Jesus, Piauí. The experimental design used was a completely randomized design (DIC) with a 3 X 3 + Witness factorial scheme, consisting of three levels of base saturation (V%) (50%, 60% and 70%) and three concentrations of potassium fertilization doses (50% below recommended; recommended, according to soil analysis; 50% above recommended) and Control, without K application, with four replications. Plant height, stem diameter, number of nodes, midrib length and leaf area were evaluated. The meteorological data were obtained in a portable meteorological station, installed inside the protected environment. Among the stages, the First Boll-Harvestpresented the highest thermal demand, with an average of 551.7 °gd and 34 days of duration, followed by the Emergence-First Floral Bud (435.6 °gd), First Floral Bud- First Flower (362.5 °gd) and First Flower-First Boll (300.3 °gd), the Sowing-Emergence phase obtained 51.4 °gd. Air temperature is the meteorological element with the greatest impact on cotton development.

THE STUDY OF ANTHROPOGENIC DISTURBANCE ON GEOPEDOGENETIC PROCESS AT THE LOWER SLOPE OF MT. UNGARAN, INDONESIA

Volcanic rocks mining activity will undoubtedly remove vegetation cover and cause the physical environment changes. Revegetation effort as part of land rehabilitation program then often found many obstacles because it was mostly conducted without adequate knowledge of detailed morphology and soil characteristics at the post-mining area. This study investigates the geopedogenetic changes, including land surface morphology, recent geomorphic processes, and soil properties caused by andesite rocks exploitation at the northern flank of Mt. Ungaran, Central Java Province of Indonesia. A digital terrain model was firstly generated from small format aerial photography acquired by an unmanned aerial vehicle (UAV) to identify the surface morphology changes due to the mining. Soil observation on field and laboratory test were conducted from samples at the affected and unaffected mining areas in order to analyse the changes on pysiochemical properties. This research exhibits that the mining activities have altered a single convex hill into a complex land surface morphology consisting of sloping zone, basins and flat area. Human disturbance on pedogenetic process at the mining area are in the form of parent material alteration that make them return to the early stage of soil development and top soil reduction that modify its genetic horizons. In addition, the changes on surface morphology and the absence of vegetation cover right after the mining ends also triggered new geomorphic processes in the form of incision and deposition on slopes and basin respectively. The finer deposit layers then become a new parent material at the basin zone. Soil laboratory data demonstrate that the affected soils tend to have a high level of base saturation, but lower C-organic and N-total levels, which result in a less favourable environment for supporting vegetation growth. A precise surface morphology design, extra soil surface protection and organic matter enhancement could be wise recommendations for land managers to control soil incision and support vegetation growth at the andesite post-mining area.

The Efficiency of Stabilized Fertilizers in Reducing Ammonia Loss Is Influenced by Liming Method

ABSTRACT Urea is the most used nitrogen (N) fertilizer worldwide, but its rapid hydrolysis on the soil surface results in N loss in the form of ammonia (NH3-N). Enzyme inhibitors have been investigated for their ability to reduce NH3-N volatilization, particularly from no-till and surface-limed soils. This study assessed the efficiency of stabilized fertilizers in reducing NH3-N volatilization under different lime rates and application methods. The experiment followed a 2 × 4 × 3 factorial design, with two liming methods (surface application and incorporation), four base saturation levels (50, 60, 70, and 90%), and three urea (45% N) sources: conventional urea, urea + N-(n-butyl)-Thiophosphoric triamide (NBPT), and urea + Boron (B) + Copper (Cu). NH3-N volatilization losses varied from 9.15 to 20.43 kg ha−1, accounting for 11.4 to 25.5% of the applied N rate. Base saturation did not influence NH3-N volatilization. Liming method, however, had a significant effect. Urea + B + Cu was effective in reducing volatilization loss only in soils ameliorated by lime incorporation (23% reduction compared with conventional urea). Urea + NBPT was effective in surface-limed and incorporated soils (up to 55.5% reduction). The results showed that soil management influences the efficiency of stabilized fertilizers and that urea + NBPT provides the best results.

Influence of base saturation on buckwheat grain and flavonoid production

Fagopyrum esculentum is highly nutritious due to its proteins of high biological value and high fiber content. Its most relevant property is nonetheless its antioxidant activity, provided by the presence of flavonoids. It is an important pseudocereal in agriculture, animal production, and human food. The objective of study was to evaluate the grain yield and flavonoid production of Fagopyrum esculentum cultivars as a function of base saturation. The experiment was carried out in a greenhouse, in a completely randomized design with four replicates. Treatments were represented by cultivars IPR 91 and IPR 92 and five base saturation levels (9, 31, 53, 75, and 97 %), in a factorial arrangement (2 × 5). Agronomic attributes and total-flavonoid and rutin contents and production were evaluated. Subsequently, the data were subjected to statistical analysis. Base saturation does not affect flavonoid production. However, base saturation influences shoot dry matter yield (maximum at 62.0% base saturation) and grain yield (maximum at 9.00%) in IPR 92. The higher-yielding cultivar is IPR 92. This is the first scientific report of base saturation in the species.

Spatial Distributions of Cadmium and Lead in Roadside Soils Along Owerri-Umuahia Highway

The research was conducted in 2019 to evaluate the spatial distribution of heavy metals (cd and pb) in roadside soil along Owerri-Umuahia highway Imo State Nigeria. Three locations were sampled-Owerri, Mbaise and Obowo. These locations are the major highways connecting Owerri-Umuahia. Soil samples were collected at a predetermined distance of 0-15 feet (ft), 15-30 ft, 30-45ft, and 45-60ft away (row) from the edge of the road. All were sample at a depth of 30 centimeter (cm) depth using soil auger. The locations were either cultivated with cassava or maize and in some cases vegetables. Reference (control) samples were also sampled from fallow (non-highway soil) lands but at a distance of 100meters (m) away from highway. Fifty four (54) samples were randomly collected, and bucked samples were replicated for treatment sources. Samples were air dried and sieved with 2mm sieve, crushed and stored in the polythene bag for laboratory activities. Analyses were done routinely. The physicochemical result (table 1) showed that the soils are mostly sandy and the pH were slightly acidic with mean value of (5.97) when compared with control (5.89). There were significant differences between locations and control with regard to macro nutrient levels. These ranges from (phosphorus (p) 14.43 to 16.06 mg/kg, Nitrogen 0.11 to 0.73 % and potassium 0.18 to 0.23 cmol.kg-1). These were significantly different when compared with control (NPK 0.54. 23.74 and 1.15) as the locations levels were lower than non-highway soils. The organic Matter (OM) where lower in highway location. The mean value were 2-12% while the control. The mean value was 2-12%, and control was 3.41%. The result followed same trend with Base Saturation and Basic Cation levels. Base Saturation (BS) were significantly different between locations and also when compared with control. The BS mean value was 77.91% while control was 84.60%. Cadmium levels at various distances, and between one location and another did not change significantly. Cadmium at distances 0-15ft, 15-30ft, 30-45ft and 45-60 ft, the mean values were 2.21, 1.87, 1.77, 2.03 and for control 2.19, 2.19, 2.02, 2.19 mg/kg respectively (table 2). For lead, at the sample distance away from road edge- 0-15ft, 15-30ft, 30-45ft and 45-60ft, the mean values were 11.7, 13.2, 12.5 , 12.0 and for control 13.22, 14.42, 13.03 and 14.14 (table 3). These slightly differences in the locations from control were not significant at p<0.05. In some cases, the control levels were higher the locations in terms of spread. From the result of the study, cadmium and lead concentrations at all the distances and spread, depth and locations were at moderate levels when compared with critical Cd and Pb established standard. Automobile movement at Owerri-Umuahia highway did not increase cadmium and lead levels spatially. The result was discussion in line with the established standard for heavy metal permissible limits

Pros and cons of fertirrigation with in natura sugarcane vinasse: Do improvements in soil fertility offset environmental and bioenergy losses?

Managing vinasse in sugarcane biorefineries currently raises a direct debate between traditional industrialists of the sucro-energy sector and researchers. While the first group identifies fertirrigation (land disposal of in natura vinasse) as a well-consolidated approach, the latter understands vinasse as a potential substrate for numerous (bio)technological applications, in addition to associating environmental issues with fertirrigation. This study offers an unbiased assessment of fertirrigation using in natura vinasse by quantifying and qualifying its pros and cons. A comparative analysis using anaerobic digestion (AD) as an alternative management approach was carried out, presenting aspects of organic matter-derived pollution and bioenergy recovery from biogas. Field data obtained in five sugarcane cultivation areas subjected to fertirrigation within the period 2012–2016 revealed the adequate buildup of macronutrients (K+, Ca2+ and Mg2+) associated with high base (51.97–81.38%) and low aluminum (0.22–2.26%) saturation levels without evidences of overfertilization and sodification. However, the inputs of biodegradable organic matter along with nutrients trigger important environmental drawbacks, with emphasis on uncontrolled methane emissions (up to 732.10 kg–CO2–eq ha−1) and polluting potential levels equivalent to that of population densities as high as 293 inhab ha−1. Energy losses in all cultivation areas assessed could provide electricity to process at least 80% of the daily milling capacity of the reference biorefinery. Hence, gains in soil fertility do not offset the losses in environmental quality when land disposing in natura vinasse, and AD seems to be the primary approach to mitigate polluting issues and enhance resource recovery in sugarcane biorefineries.

Lime and phosphogypsum application management: changes in soil acidity, sulfur availability and crop yield

Oxisols ( Latossolos ) are widely distributed in tropical zones and generally characterized by high levels of surface and subsurface acidity. In Brazil, most Oxisols are managed under no-till conditions with surface application of acidity amendments. This study aimed to evaluate lime application strategies (incorporated and surface) for achieving the desired soil base saturation (BS%) levels (44, 60, 70, and 90 %) and the effect of phosphogypsum + lime application on soil chemical properties as well as wheat and [...]

High‐throughput phenotyping of soybean genotypes under base saturation stress conditions

AbstractThe search for high‐yielding genotypes and that are tolerant to abiotic stresses has been a major goal in plant breeding. Thus, the use of technologies such as precision agriculture associated with remote sensing tools for plant phenotyping has increased. The hypothesis of this research was that soya bean genotypes respond differently to low and adequate base saturation levels in the soil and that vegetation indexes can be efficient auxiliary tools in plant phenotyping for this purpose. The objective of this study was to evaluate the nutritional status and agronomic performance of soya bean genotypes grown in low and recommended base saturation conditions using high‐throughput phenotyping. The research was carried out in 2017/2018 and 2018/2019 crop seasons, in which two field experiments in each season were installed. In experiment I, genotypes (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10) were evaluated without soil correction (low saturation condition). In experiment II, liming was performed three months before sowing of the genotypes to raise the base saturation to 60% (recommended saturation). Canopy spectral behaviour at the following wavelengths was evaluated: green (550 nm), red (660 nm), red edge (735 nm) and near‐infrared (790 nm), and the vegetation indices (Vis) NDVI, SAVI, EVI and MSAVI were calculated. The variables evaluated were leaf calcium and magnesium contents and grain yield. The use of VI’s was efficient in assessing the performance of genotypes soya bean at different base saturation levels. The EVI showed moderate correlation with the nutritional and agronomic variables measured in each base saturation level. The approach used enabled both to identify genotypes tolerant to low base saturation soils and the ones with better response to liming.

Short-term effects of lime and phosphogypsum reapplication methods on wheat and maize nutrition

Lime (L) and phosphogypsum (GY) are indispensable inputs in acidic soils that can alter the nutritional status of crops. The objective of this study was to evaluate the nutritional status and productivity of maize and wheat after the application of L and GY. The treatments consisted of a 2 x 4 + 3 factorial, with two forms of L application: surface (SL) and incorporated (IL) to obtain different levels of base saturation (BS%): 44, 60, 70 and 90; additionally three treatments involving the use of GY were evaluated: BS% 60 + 3.71 Mg ha−1; BS% 70 + 3.71 Mg ha−1 and BS% 70 + 7.42 Mg ha−1 of GY. The increase in BS% favored the absorption of magnesium (Mg) (SL and IL) and phosphorus (P) (IL) content in maize. IL increased the contents of nitrogen (N) and sulfur (S) and maize yield compared with SL. GY increased the maize yield by 7.6% compared with the control (BS 44%). Maize productivity correlated positively with calcium (Ca) (0.65), S (0.78) and N (0.54) leaf contents. In wheat, the increase in BS% reduced absorption of potassium (K) (SL and IL) and increased leaf Ca and Mg (IL) contents. Wheat yield correlated positively to leaf Ca (0.61) and S (0.62). Lime incorporation decreased wheat yield. High doses of GY (7.42 Mg ha−1) reduced absorption of Mg (maize and wheat) and K (maize). It is better to apply GY than to till the soil, thus maintaining uninterrupted no-till.