The investigations were carried out during the period 2006-2011 in the land of the Water resources management institute of ASU, in the village of Lipliūnai on Endocalcari Endohypogleyic Cambisol (CMg-n-w-can). The base of investigations is 3 drainage systems, which contain cereals differing in fertilization and grass crop rotations. The aim of investigations is to determine the crop rotations differing in fertilization and these relations with cycles of phosphorus in agroecosystem. Higher productive was perennial grass crop rotation. In the conditions of cereal crop rotations this productive was 3-46% lesser. The highest concentration of P-PO4 3- in drainage water was received in the conditions of higher fertilization cereals crop rotation while highest concentration of total P was in the conditions of grass crop rotation. The concentration of P-PO4 3- in drainage water essentially depends on amount of mobile P2 O5 in soil, fertilization, productivity of field crops, drainage runoff as well as cumulative balance of P. The highest leaching of P-PO4 3- and total P by drainage was received under the conditions of higher fertilization cereals crop rotation. The leaching of P-PO4 3- essentially depends on fertilization, drainage runoff as well as cumulative and yearly balance of P. The application of all crop rotations was distinguished by positive P balance.

To promote the future of abandoned lands management and the reduction of fossil energy consumption in Latvia, the establishment of energy crops plantation facilities, including perennial grasses, was investigated. The objective – suitability of several perennial grasses for bio-energy production under condition of Latvia. The aim of the current research to evaluate the experimental field conditions for the cultivation of perennial grasses. The perennial grasses are modest in terms of soil conditions, they are environmentally friendly, as well as provide high yields of biomass with adequate quality for bio-energy production without large investments. With increasing amounts of bio-energy production the amounts of various by-products which are profitable to utilize as energy crops fertiliser will also increase. It is essential that plant nutrients return back into circulation by creating a complete cycle. In order to test in practice the possibility of creating this complete cycle of growing perennial grasses, an experimental field was chosen at the Research Institute of Agriculture in Skriveri. In the summer of 2011, before trials establishment, the conditions of soil were examined at four depths: 0 – 20 cm; 20 – 40 cm; 40 – 60 cm and 60 – 80 cm. The analyses showed that the experimental field conditions were appropriate for growing of perennial grasses. The results of the soil agrochemical analysis will be a base for future studies of usage efficiency of different fertiliser types on perennial grass productivity and nutrient recycling opportunities in energy crop plantations.

The yield and quality (1000 kernel weight, protein, nitrogen, phosphorus and potassium content) of peas was studied in cultivar 'Madonna'. The peas (Pisum Sativum L.) were part of the five-year crop rotation experiment where red clover (Trifolium pratense L.), winter wheat (Triticum aestivum L.), peas, potato (Solarium tuberosum L.) and barley (Hordeum vulgare L.), were following each other. There were two production variants which followed the crop rotation. In one variant mineral fertilizers and pesticides were used, and the other variant was conversion to organic without any synthetic agrochemicals. In mineral fertilizing variants the background in all variants was N20, P25, and K95 kg haE-1. The previous crop was winter wheat which received in fertilized variants mineral fertilizers with the background of P25 and K95 kg haE-1, the N amount varied from 0 to 150 kg haE-1. The aim of this paper was to study a mineral fertilizing after-effect on the peas which followed the winter wheat. Herbicide MCPA 750 was used. In conversion to organic, the pea grains which followed the crop rotation and mineral fertilizing Nl50 after-effect variants had higher yield, protein and nitrogen content compared to the other variants where mineral fertilizing after-effect was investigated. Phosphorus contents were higher in NO, and conversion to organic variants. Potassium content remained lower in Nl00, and Nl50 mineral fertilizing after-effect variants. The 1000 kernel weight was significantly higher in the variant of conversion to organic compared to the other variants.

New types of polymer fertilizer series ‘Vitanoll’ are used in adaptive-varietal agro technology in the cultivation of seed potatoes. The experiments were conducted on sod-podzolic soils, typical of the North-West region of the Russian Federation. The aim of the research was to study the effect of new polymer fertilizers on potato yield. Research tasks included assessing the effect of various polymer fertilizers (Polymer-N, Polymer-P, Polymer-K.), as well as the effect of Polymer-N on different potato varieties. Based on the studies conducted, the most responsive potato varieties to polymeric fertilizers with nitrogen were identified. They turned out to be Salin (increase of 7.1 t haE−1) and Mocart (increase of 4.1 t haE−1). Evaluation of the influence of different types of polymer fertilizers revealed that the most effective are polymer fertilizers with potassium.

In 1999-2003, the investigations were carried out in Juodkiskis study object of Water Management Institute of Lithuanian University of Agriculture. Study scheme is composed of three treatments: treatment I -slurry applied, treatment II - mineral fertilizers applied; treatment III - no fertilization. Test field is drained, drain spacing is 15 m; draining depth is 1.2 m. During the crop rotation the following plants were grown: spring wheat with undercrop, red clover (1st year of use), red clover (2nd year of use), sugar beet, and spring rape. The objective of studies was to determine the effect of cultivated crops on drainage water quality. As the study results have show, N total concentrations contained in drainage water increased due to higher fertilization rates and inorganic nitrogen accumulated in the soil. Neither fertilization nor amount of mobile phosphorous contained in the soil made any effect on Ptotal concentrations in drainage water. In arable land, Ntotal concentrations contained in drainage water were 2.3 times higher than those in drainage water of the field, where red clover was grown. Ptotal concentrations were higher in the field with red clover. According to the rates determined in Lithuania, drainage water is not polluted with phosphorus, while average annual Ntotal concentrations exceeded the maximum allowable (MAC) when spring wheat with undercrop and sugar beet was grown.

In April 2021, the Sri Lankan Government banned imports of agrochemicals, including chemical fertilizers, to make Sri Lanka the first fully organic and chemical fertilizer-free country globally. The ban was justified by human and environmental health concerns, such as many cases of kidney failure in the central parts of Sri Lanka. While previous policies had envisioned a stepwise transition, the sudden ban jolted the agriculture sector. However, it was aligned with the emerging national economic crisis with drastically declining foreign exchange reserves that restricted the import of commodities, including fertilizer for distribution at subsidized prices. The ban was also opportune because fertilizer prices peaked on international markets in 2022. Without any transitional time, the thrust for organic fertilizers failed to satisfy demand or obtain the required crop nutrients resulting in severe agricultural losses. After the first data on decreasing yields were revealed, the government lifted the chemical fertilizer ban on December 1, 2021, but it was too late as the cropping season had arrived. Without financial reserves to import fertilizer, the donor community was urged to assist. This paper addresses: (1) justification of the ban, (2) the feasibility of transitioning to organic fertilizers based on the available biomass to replace chemical fertilizers; and (3) the related cost implications. The scenarios focus on irrigated paddy rice and the plantation sector that underpin the national economy. Undervalued nutrient sources are also considered as well as the constraints to and implications of such a transition beyond Sri Lanka’s frontiers.