The aim of the study was to identify new mathematical models and strategies that can characterize the behavior of pollutants accumulating in the soil over time, considering the special characteristics of these chemicals that cannot be degraded or destroyed easily. The paper proposes a statistical model for assessing the accumulation of Zn in the lettuce (Lactuca sativa L.), based on three indicators that characterize the development of lettuce plants over time. The experimental data can be used to obtain interpolated variations of the mass increase functions and to determine several functions that express the time dependence of heavy metal accumulation in the plant. The resulting interpolation functions have multiple applications, being useful in generating predictions for plant growth parameters when they are grown in contaminated environments, determining whether pollutant concentrations may be hazardous for human health, and may be used to verify and validate dynamic mathematical contamination models.

Soil is one of the natural reservoirs of the carbon biogeochemical cycle, incorporating approximately 6000 billion tons of carbon. Given that with the industrial development more and more carbon is emitted into the atmosphere, solutions, technologies and methods are being sought to reduce this carbon or, where appropriate, it is not eliminated into the atmosphere. The purpose of this paper is to study and identify the simplest methods to be applied in agriculture, for soil processing, by identifying the techniques, technologies and equipment to achieve this without turning the furrow, so that the carbon incorporated in the soil by plants remains sequestered there.

Heavy metals are naturally occurring elements, but their various applications have led to their wide circulation in the environment, raising concerns over their latent effects on the environment and human health. Their toxicity depends on numerous factors, including chemical species, concentration of heavy metal ions, environmental factors, etc. Experimental studies on the single or cumulative effects of heavy metals on plants are complex, time consuming and difficult to conduct. An alternative is mathematical modeling, which can include different factors into an integrated system and can predict plant and environmental behavior under multiple stressors. This paper presents a mathematical model that simulates the dependence of temperature, concentration of Zn in the soil and the subsequent bioaccumulation in lettuce (Lactuca sativa L.); respectively, the reaction of lettuce to Zn contamination. The main results consist of three mathematical models, based on systems of ordinary differential equations and checking their predictions with available experimental data. The models are applied to predict an optimal harvest time of lettuce with low concentration of Zn, in identifying the availability of the analyzed species to phytoremediation operations and the possibility of maneuvering certain control factors to reduce or increase the intensity of the bioaccumulation process.

In this paper, a few assessments of the optimal parametric combinations in the operating regime of agricultural aggregates with ploughs of variable width are made. The starting point was from a classic expression of the tillage draft force required for traction. In order to find optimal points, some problems of constrained extreme have been formulated. Extremes provided by the optimal working width and speed have been found. Such optimal points have existed in the literature, for about half a century. Using these theoretical estimates of the optimal points sought, assessments of the possibilities for their experimental validation were made. Basic conditions for an experimental plan are formulated to highlight such optimal points.

The problem of grain storage and storage can be approached from two perspectives: storage and storage of cereals and technical plants within individual agricultural holdings; storage and storage of cereals and technical plants within agricultural associations and companies. At the level of Romania, the storage and storage of cereals at small agricultural producers are deficient in terms of ensuring optimal storage conditions according to standards. These variants include: preservation at low temperatures; preservation by active aeration; self-preservation; chemical preservation; conservation with the help of radiation. In the paper we will approach the conservation by active aeration because it folds better for small agricultural producers. Proper aeration is one of the most important processes in a grain storage system and is essential for maintaining the quality of stored products. Aeration means the movement of a relatively small volume of air through the grain mass in order to control the temperature of the grain and to reduce the risk of product degradation. The two main objectives of aeration are to maintain a uniform temperature in the grain mass and at the same time the temperature must be as low as possible from a practical point of view. The paper will present the results of experiments for storing bulk grain in a metal cell with central aeration system, which is based on a patent. This type of storage system can be used successfully in small agricultural producers.