Agriculture is facing many challenges at the moment and, especially, in the future. This is a consequence of the simplistic linear approach to agriculture intensification which is now dominating all over the world as the industrial model of agricultural intensification, instead of a circular holistic (systemic) one. Agricultural systems are largely based on intensive application of inputs, like mineral fertilizers, pesticides, irrigational water etc. as compared to natural ecosystems, where recycling of nutrients and energy, together with self-regulatory biological mechanisms, are the basis for their sustainable co-evolution. Nutrients in the soil have a chemical composition, but an biological origin. The law of returning, formulated by Justus von Liebig, has emphasized mainly the importance of returning back to the soil of nutrients taken up by crops. Only at the end of his life Justus von Liebig has realized the importance of returning back to the soil not only of nutrients, but also of energy, which he had underestimated before [6]. Nutrients in the soil are the consequence of permanent synthesis and mineralization of soil organic matter. Simultaneously, the physical and biological properties of soils are improved by good (sustainable) crop production, which all together determines a good quality of the harvest and a healthy soil. That’s why replenishment of NPK, taken up by crops only from mineral fertilizers, can’t provide a sustainable building of soil fertility. According to our experimental data, the share of soil fertility in yield formation consists from 75 up to 97 % (depending on crops and crop rotations) [1]. Healthy soils don’t react or react very poor on the application of mineral fertilizers. The results obtained in the long-term field experiments, with different crop rotations and continuous cropping on different systems of fertilization at Selectia Research Institute of Field Crops (Balti, Republic of Moldova), proved a higher efficiency of mineral fertilizers in continuous cropping(monoculture) and in crop rotations with less favorable predecessors than in crop rotations with more favorable predecessors [1]. It means that by respecting crop rotations it is possible to reduce the application of mineral fertilizers, especially of nitrogen. The same is true for fields (plots) with the application of composted farmyard manure, where supplementary application of mineral fertilizers alone or together with organic fertilizers don’t provide an extra yield for different crops relatively to application of composted farmyard manure alone [2]. Modern agriculture focuses mainly on NPK fertilization without paying enough attention to carbon fertilization, as the main source of energy for soil biota on the whole web chain of the soil ecosystem, determining the level of soil fertility, soil vitality and soil functionality. More than this, by using nitrogen from mineral fertilizers without replenishment the stocks of fresh carbon (organic matter) sources in the soil, the mineralization losses of soil organic matter are increasing. This consequently contributes to the reduction of the stocks of total nitrogen and phosphorus in the soil. The more nitrogen from mineral fertilizers is used the poorer the soils become and the more nitrogen must be applied to reach the same yield [9]. This statement was proven in various long-term field experiments in all over the world, including our long-term field experiments on typical chernozem from the Balti steppe of Moldova [2, 7]. Permanent addition of fresh organic matter in the soil allows to keep the balance between different groups of soil microorganisms (bacteria, fungi, lichens, worms, insects) – zymogen and avtohton groups (according to Vinogradschi S.N., 1952) [8]. The ratio between labile and stabile fractions of soil organic matter is crucial for a healthy soil, for bringing health on the whole food chain: Soil-Crops-Animals-People-Planet (Jan Diek van Mansvelt, 2016) [3, 9]. Soils have many functions besides providing productivity both in natural and agro-ecosystems: water purification, carbon sequestration, habitat for soil biota etc [5]. Only healthy soils can provide ecosystem and social services. Ernst Haeckel couldn’t divide the eco-system health from human health (cited by Dediu I.) [4]. S.A. Howard in his” An Agricultural Testament” was tracing a direct connection between the health of the soils (soil fertility) and such diseases as: soil erosion, incapacity of soils to provide nutrients for crops, crop diseases, people and animal health [3]. Conclusions: 1. Modern agriculture requires an ecological restructuring in order to provide ecosystem and social services. 2. Sustainable development of agriculture, including crop nutrition is possible only on the basis of restoration of soil fertility, which can bring health on the whole food chain. Bibliography: 1. Boincean B.P. Fifty Years of Field Experiments with Crop Rotations and Continuous Cultures at the Selectia Research Institute of Field Crops. In: Soil as World Heritage, edited by David Dent, Springer, 2014, pp.175-200 2. Boincean B.P., Nica L.T., Stadnic S.S. Productivity and Fertility of the Balti Chernozem Under Crop Rotation with Different Systems of Fertilization. In: Soil as World Heritage, edited by David Dent, Springer, 2014, pp.209-232. 3. Sir Albert Howard. An Agricultural Testament. Oxford University Press, New York and London, 1943, 223p. 4. Dediu Ion.150 years since ecology is authenticated as a distinct biological science. In: Problems of ecology and geography in the context of sustainable development of the Republic of Moldova: achievements and perspectives, Chisinau, September 14-15, 2016, published by Vasiliana’98, Iasi, 2016, pp.3-18 5. Lal Rattan. Abating Climate Change and Feeding the World Through Soil Carbon Sequestration. In: Soil as World Heritage, edited by David Dent, 2014, Springer, pp.443-458 6. Liebig Justus Chemistry as an attachment for crop physiology. Moscow, Leningrad, Selihozgiz, 1936 (in Russian) 7. Mulvaney R.L., Khan S.A. and Ellsworth T.R. Synthetic Nitrogen Fertilizers Deplete Soil Nitrogen: A Global Dilemma for Sustainable Cereal Production. Journal of Environmental Quality, Vol. 38, 2009, pp.2295-2314 8. Vinogradschi S.N. Soil microbiology. Problems and methods. Publisher-Academy of Sciences of USSR, Moscow, 1952, 792p. 9. Van Mansvelt, J.D. Perceptions of plant nutrition in agriculture. Some consequences for soil fertility, human health and global nutrition, an essay in contextualization (in print).