Sowing Systems as a Factor of Grain Yield in Sunflower Production

The paper presents the results of a triennial study of the sowing system influence on the yied, grain weight per head, plant set per ha and of the grain moisture of a medium-early sunflower hybrid . Standard sowing was performed with the PSK OLT sowing machine at a row spacing amounting to 70 cm, while a twin row sowing was performed with the MaterMacc Twin Row-2 sowing machine at a row spacing of 22*48 cm. Both sowing machines were adjusted according to the ISO standard 7256/1 and 7256/2, with a high QFI index (PSK OLT: 96.32 %; MaterMacc Twin Row-2: 93.93 %). The research was conducted at the Gorjani Experimental Field on psudogley bearing the textured markings of a silty loam, with a weak acid reaction and a small amount of humus. An analysis of variance determined a statistical significance of the sowing system on the grain yield and the grain mass per sunflower head. Sowing in twin rows achieved the higher yields for all three research years : 19.59% in 2017, 19.11% in 2018, and 18.45% in 2019. Plant density was not statistically significantly affected by the sowing systems and vegetation year, but the grain moisture was statistically significantly different between the analyzed research years .

Organic Amendment and Mulching Enhanced the Growth and Fruit Quality of Squash Plants (Cucurbita pepo L.) Grown on Silty Loam Soils

Adoption of suitable organic fertilizers and soil mulching are useful tools to enhance soil quality, which will inevitably lead to improved growth and yield of crops. Little is known about the soil organic amendments and Azolla (Azolla pinnata) under soil organic mulching on the growth and yield of squash plant (Cucurbita pepo L.). A comparative study mainly focused on the impacts of organic fertilizer treatments on soil fertility and squash growth under wheat straw mulch was conducted on wooden boxes filled with silty loam soil. Wheat straw, as an organic mulch, and five organic-fertilization treatments were added to the soil. Wheat straw with a size of <2 cm was added to the soil surface with a 2 cm thickness. The fertilization treatments were: control (CO), chemical fertilizer (CF), compost (CT), vermicompost (VC), and dry Azolla (DA). Wheat straw mulch had positive effects on the soil properties, growth, and yield. The maximum fruit yield was obtained from the soil fertilized with DA under wheat straw mulch, while the lowest one was found in the control without mulching. Azolla and organic fertilizers showed a remarkable superiority over the mineral fertilization in increasing the soil fertility as well as the growth and quality of squash fruits; this superiority increased under the wheat straw mulching system. The application of recommended mineral fertilization (CF), compost (CT), vermicompost (VC), and dry Azolla (DA) under wheat straw mulch increased the soil available-N by 2, 20, 12, and 29%, respectively, above the control (CO), while these organic fertilizers without mulching increased the soil available-N by 11, 32, 26, and 48%, respectively. The production of vegetable crops such as squash plants requires the addition of organic fertilizers and mulching to increase yield and quality of fruits.

Ground-Based Hyperspectral Remote Sensing for Estimating Water Stress in Tomato Growth in Sandy Loam and Silty Loam Soils

Drought and water scarcity due to global warming, climate change, and social development have been the most death-defying threat to global agriculture production for the optimization of water and food security. Reflectance indices obtained by an Analytical Spectral Device (ASD) Spec 4 hyperspectral spectrometer from tomato growth in two soil texture types exposed to four water stress levels (70–100% FC, 60–70% FC, 50–60% FC, and 40–50% FC) was deployed to schedule irrigation and management of crops’ water stress. The treatments were replicated four times in a randomized complete block design (RCBD) in a 2 × 4 factorial experiment. Water stress treatments were monitored with Time Domain Reflectometer (TDR) every 12 h before and after irrigation to maintain soil water content at the desired (FC%). Soil electrical conductivity (Ec) was measured daily throughout the growth cycle of tomatoes in both soil types. Ec was revealing a strong correlation with water stress at R2 above 0.95 p < 0.001. Yield was measured at the end of the end of the growing season. The results revealed that yield had a high correlation with water stress at R2 = 0.9758 and 0.9816 p < 0.01 for sandy loam and silty loam soils, respectively. Leaf temperature (LT °C), relative leaf water content (RLWC), leaf chlorophyll content (LCC), Leaf area index (LAI), were measured at each growth stage at the same time spectral reflectance data were measured throughout the growth period. Spectral reflectance indices used were grouped into three: (1) greenness vegetative indices; (2) water overtone vegetation indices; (3) Photochemical Reflectance Index centered at 570 nm (PRI570), and normalized PRI (PRInorm). These reflectance indices were strongly correlated with all four water stress indicators and yield. The results revealed that NDVI, RDVI, WI, NDWI, NDWI1640, PRI570, and PRInorm were the most sensitive indices for estimating crop water stress at each growth stage in both sandy loam and silty loam soils at R2 above 0.35. This study recounts the depth of 858 to 1640 nm band absorption to water stress estimation, comparing it to other band depths to give an insight into the usefulness of ground-based hyperspectral reflectance indices for assessing crop water stress at different growth stages in different soil types.

Purification Performance of Filtration Process for Pig Slurry Using Marine Sands, Silty Loam Soils, Fly Ash and Zeolite

Filtration is a simple ecological process for the treatment of effluents. This research examined the physicochemical properties of micronutrients, macronutrients, and heavy metals (HM) removed after the slow filtration of pig slurry (PS) through multiple media: sands, silt loam soils, fly ash, and zeolite. The objective was to find a new layer that can be added to our constructed wetland (CW) to improve its efficiency and study how the slurry reacts to these natural materials. The filtration achieved an approximate removal rate of 99.99% for total suspended solids (TSS) and nitrogen and 61, 94, 72, and 97%, respectively, for electrical conductivity (EC), turbidity, chemical oxygen demand (COD), and five-day biological oxygen demand (BOD5). The two sands, soil 1, and zeolite, had a macronutrient reduction median of 60%, whereas soil 2, 3, 4, and fly ash released macronutrients such as Na, Ca, and Mg. All the media achieved nearly 99.99% micronutrient removal for Fe and Zn. The Cu removal rate was over 86% except for sand 1 and 2 and soil 1, which reduced it to only 46%; the overall Mn removal rate was more than 80% except for soil 3 and soil 4, where it was only 9%. Zeolite had a 99.99% removal capacity for HM as opposed to sand 2, soil 4, and fly ash, which released some HMs (Ni, Cu). This inexpensive and abundant media filtration process is sound technically and financially sound and seems to be an ideal cost-efficient treatment for pig slurry.

Monitoring Soil and Ambient Parameters in the IoT Precision Agriculture Scenario: An Original Modeling Approach Dedicated to Low-Cost Soil Water Content Sensors

A low power wireless sensor network based on LoRaWAN protocol was designed with a focus on the IoT low-cost Precision Agriculture applications, such as greenhouse sensing and actuation. All subsystems used in this research are designed by using commercial components and free or open-source software libraries. The whole system was implemented to demonstrate the feasibility of a modular system built with cheap off-the-shelf components, including sensors. The experimental outputs were collected and stored in a database managed by a virtual machine running in a cloud service. The collected data can be visualized in real time by the user with a graphical interface. The reliability of the whole system was proven during a continued experiment with two natural soils, Loamy Sand and Silty Loam. Regarding soil parameters, the system performance has been compared with that of a reference sensor from Sentek. Measurements highlighted a good agreement for the temperature within the supposed accuracy of the adopted sensors and a non-constant sensitivity for the low-cost volumetric water contents (VWC) sensor. Finally, for the low-cost VWC sensor we implemented a novel procedure to optimize the parameters of the non-linear fitting equation correlating its analog voltage output with the reference VWC.

Potassium Adsorption Phenomenon in Calcareous Soils of Shahrazur Plain

A laboratory study for adsorption of potassium (K) determination was conducted on six soils located in Sharazur plain from the Kurdistan Region of Iraq in 2021 using the batch technique method. Potassium (K) adsorption isotherms were achieved by equilibrating 5.0 g of soil samples with eight grades of K (0 to 300 mg L-1) as KCl in 50 ml of 0.01M CaCl2 solution. To match the data of adsorption, Freundlich, Langmuir, and Temkin adsorption isotherms were used. The results show that the amount of adsorbed K ranged between (45.78 to 52.49) % added K. The Freundlich model fit the equilibrium K adsorption data better for the Serwan location of soil (silty loam), as demonstrated by a greater coefficient of determination (R2 =0.90). The value of heterogeneity factor 1/n for the Freundlich model ranged from (0.34 to 0.47) kg mg-1, which was less than one. The sorption processes for all of the studied soils were normal adsorption. The constant of the Langmuir isotherm (KL) aligned from (0.107 to o.425) L mg-1. Smaller KL values mean that more adsorbed K would be transformed to a non-exchangeable form, either through the creation of crystalline K or through ion occultation. The RL values indicate the type of isotherm, the values of RL> 1 that means the adsorption nature to be unfavorable. The Temkin equilibrium binding constant (AT) was high for all studied soils except the soils of Bestan Sur and Grdigo locations, the high value of AT indicates high binding energy. The Temkin constant (bT) ranged from (10.46 to 13.47) J mole-1 that was related to the nature of the adsorption energy, a positive value indicates that the adsorption process is exothermic.

Changes in soil microbial community and activity caused by application of dimethachlor and linuron

Soil microorganisms and their activities are essential for maintaining soil health and fertility. Microorganisms can be negatively affected by application of herbicides. Although effects of herbicides on microorganisms are widely studied, there is a lack of information for chloroacetamide herbicide dimethachlor. Thus, dimethachlor and well known linuron were applied to silty-loam luvisol and their effects on microorganisms were evaluated during112 days long laboratory assay. Dimethachlor and linuron were applied in doses 1.0 kg ha−1 and 0.8 kg ha−1 corresponding to 3.33 mg kg−1 and 2.66 mg kg−1 respectively. Also 100-fold doses were used for magnification of impacts. Linuron in 100-fold dose caused minor increase of respiration, temporal increase of soil microbial biomass, decrease of soil dehydrogenase activity, and altered microbial community. Dimethachlor in 100-fold dose significantly increased respiration; microbial biomass and decreased soil enzymatic activities. Microbial composition changed significantly, Proteobacteria abundance, particularly Pseudomonas and Achromobacter genera increased from 7 to 28th day. In-silico prediction of microbial gene expression by PICRUSt2 software revealed increased expression of genes related to xenobiotic degradation pathways. Evaluated characteristics of microbial community and activity were not affected by herbicides in recommended doses and the responsible use of both herbicides will not harm soil microbial community.