Prediction Model of Soil Electrical Conductivity Based on ELM Optimized by Bald Eagle Search Algorithm

Soil electrical conductivity is one of the indispensable and important parameters in fine agriculture management, and a suitable soil electrical conductivity can promote good plant growth. Prediction model of soil electrical conductivity is constructed to effectively obtain the conductivity values of soil, which can provide a reference basis for irrigation and fertilization management and prediction evaluation in fine agriculture. Prediction model of soil electrical conductivity based on extreme learning machine (ELM) optimized by bald eagle search (BES) algorithm is proposed in this paper. In the prediction model, the input weights and bias values of the ELM network were optimized using the BES algorithm, and the performance of the model was evaluated with parameters such as mean square error (MSE), coefficient of determination (R^2). Also, the correlations of parameters such as soil temperature, moisture content, pH, and water potential in the soil conductivity prediction model were determined using the exploratory data analysis (EDA) and HeatMap heat map tools. Finally, the proposed model was compared with back propagation neural network (BP), radial basis function networks (RBF), support vector machine (SVM), gated recurrent neural network (GRNN), long short-term memory (LSTM), particle swarm algorithm (PSO) optimization ELM, genetic algorithm (GA) optimized ELM prediction model. The experimental results showed that MSE, R^2 of the proposed model are 4.09 and 0.941, which are better than the other models. Also the results verified the effectiveness of the proposed method, which is a feasible prediction method to guide the irrigation and fertilization management in fine agriculture, because of its good prediction effect on soil conductivity.

Wireless Underground Sensor Network for Monitoring Various Fields Using Magnetic Induction

The frequent accidents of mining safety caused severe losses and massive cost losses. The global mining sector urgently needs to improve operational efficiency and the overall safety of mines. This article suggests a WUSN based mining safety monitoring. The monitoring system collects temperature, moisture, soil vibration and gas values around the mine, and then transmits the data through wireless underground sensor network. Here Transmission based on magnetic induction (MI) is being suggested, in this approach soil is medium for communication so based on the soil conductivity the measured information are transferred. It is also an early warning system, which will help all miners in the mine to save their lives before a victim happens.

Differences in PItotal of Quercus liaotungensis seedlings between provenance

The performance index of overall photochemistry (PItotal) is widely used in photosynthesis research, but the PItotal interspecies differences are unclear. To this end, seeds of Quercus liaotungensis from 10 geographical provenances were planted in two different climate types. Two years later, leaf relative chlorophyll content (SPAD) and chlorophyll a fluorescence transient of seedlings were measured. Meanwhile, the environmental factors of provenance location, including temperature, precipitation, solar radiation, wind speed, transpiration pressure, and soil properties, were retrieved to analyze the trends of PItotal among geographic provenance. The results showed that, in each climate type, there was no significant difference in SPAD and electron transfer status between PSII and PSI, but PItotal was significantly different among geographic provenances. The major internal causes of PItotal interspecies differences were the efficiency of electronic transfer to final PSI acceptor and the number of active reaction centers per leaf cross-section. The main external causes of PItotal interspecies differences were precipitation of the warmest quarter, solar radiation intensity in July, and annual precipitation of provenance location. PItotal had the highest correlation with precipitation of the warmest quarter of origin and could be fitted by the Sine function. The peak location and fluctuating trend of precipitation—PItotal fitted curve were different in two climate types, largely due to the difference of precipitation and upper soil conductivity in the two test sites. Utilizing the interspecific variation and trends of PItotal might be a good strategy to screen high and stable photosynthetic efficiency of Q. liaotungensis provenance.

Transient Analysis of Multiphase Transmission Lines Located above Frequency-Dependent Soils

This paper evaluates the influence of frequency-dependent soil conductivity and permittivity in the transient responses of single- and double-circuit transmission lines including the ground wires subjected to lightning strikes. We use Nakagawa’s approach to compute the ground-return impedance and admittance matrices where the frequency-dependent soil is modeled using Alípio and Visacro’s model. We compare some elements of these matrices with those calculated by Carson’s approach which assumes the frequency constant. Results show that a significant difference can be obtained in high resistive soils for these elements in impedance and admittance matrices. Then, we compute the transient responses for single- and double-circuit lines with ground wires located above soils of 500, 1000, 5000, and 10,000 Ω·m considering the frequency constant and frequency-dependent parameters generated for two lightning strikes (subsequent stroke and Gaussian pulse). We demonstrate that the inclusion of frequency dependence of soil results in an expressive reduction of approximately 26.15% and 42.75% in the generated voltage peaks in single- and double-circuit lines located above a high-resistive soil. These results show the impact of the frequency-dependent soils that must be considered for a precise transient analysis in power systems.

Humic Substances With Mineral Fertilization on Nutrient Availability in Irrigated Soil

This study aimed to evaluate the alternative use of humic substances (humic and fulvic acid) combined or not with mineral fertilization containing Nitrogen (N), Phosphorus (P) and Potassium (K) in the process of nutrient retention in the soil. For this, an experiment was conducted in a greenhouse with PVC columns of 40 cm high and 5 cm in diameter, where they were filled with Oxisol sample, being half of the treatments fertilized with NPK and half without at. Humic substances were added at doses equivalent to 0, 60, 120 and, 240 L ha-1. After this, 10 irrigations were made with 32 mm rain simulation. After 30 days, soil samples were collected in the upper (0-20 cm) and lower (20-40 cm) layers of the columns. Soil samples were evaluated for P, K, Ca, Mg content, pH, and soil conductivity. The experiment was in a completely randomized design, with a factorial statistical scheme of 2 × 2 × 4 with three replicates. The results showed that mineral fertilization complemented with the use of humic acid promoted a higher residual effect of Ca and K in the soil after 30 days. The fulvic acid, when used in a complementary way to mineral fertilization, promoted a higher amount of P in the soil. In the absence of mineral fertilization, the effect of humic substance use is low on the availability of nutrients in the soil.

Secreted Salt Increases Reaumuria Soongarica 's Ability to Compete in Grassland Areas

Background: The aim of this study was to identify and explore the community formation mechanism of R. soongarica in the eastern Mongolian Plateau grassland. The experimental site was located in an ancient lake basin with saline soil in a desert steppe. Results: Soil conductivity of R. soongarica was significantly higher than that of the two herbs, S. glareosa and A. polyrhizum, at all soil depths (P ≤ 0.001). The daily salt secretion rate ranged from 1% to 2% of the fresh leaf weight in the different communities and increased with increased soil conductivity. With increased canopy size of R. soongarica, the distance between the shrubs and herbs also increased. The correlation between the R. soongarica canopy diameter and the distance to the nearest S. glareosa (R2 = 0.4065; P < 0.05) was higher than that to the nearest A. polyrhizum (R2 = 0.1256; P < 0.05). The growth of the three species was not salt-dependent; however, R. soongarica was significantly more salt-tolerant than the two herbs. The two herbs significantly limited the growth of R. soongarica seedlings at low soil conductivity (≤ 600 µS/cm), but not at high soil conductivity (≥ 1000 µS/cm). Conclusions: Salt secretion by R. soongarica leaves results in the formation of a “saline island,” which leads to soil conductivity increasing significantly under the canopy of R. soongarica. This increase in soil conductivity of the saline island effectively reduces the interspecies competition advantage of the two herbs. This highlights the competitiveness of R. soongarica in salt-stressed environments and facilitates the establishment of this desert shrub in saline regions on the desert steppe.