Dynamic phosphorus and nitrogen yield response model for economic optimisation

This paper provides an approach for modelling joint impact of two main nutrients in crop production for situations where there are available separate datasets for nitrogen and phosphorus fertiliser field experiments. Developing yield response models for Finnish spring barley crops (Hordeum vulgare L.) for clay and coarse soils and applying the models for dynamic economic analysis demonstrate the modelling approach. Model selection is based on iterative elimination from a wide diversity of plausible model formulations. Nonlinear weighted least squares method was utilised in estimation of the yield response models and dynamic programming was utilised in economic analysis. Our results suggest that fertiliser recommendations can be insufficient if soil phosphorus dynamics are ignored. Further, the optimal fertilisation rates for nitrogen and phosphorus, as well as the economic alternative costs of agri-environmental programmes depend on the soil texture of production area. Therefore, the efficiency of such programmes could be improved by targeting different fertilisation limits for different soil textures. In addition, uncertainty analysis revealed that the parameter uncertainty had a greater effect on the model output than the structural uncertainty. Further, the interaction of nitrogen and phosphorus fertilisers appeared to be a factor of relatively minor importance. The modelling approach and the model structure can be extended to other geographical areas, given that adequate datasets are available.This paper provides an approach for modelling joint impact of two main nutrients in crop production for situations where there are available separate datasets for nitrogen and phosphorus fertiliser field experiments. Developing yield response models for Finnish spring barley crops (Hordeum vulgare L.) for clay and coarse soils and applying the models for dynamic economic analysis demonstrate the modelling approach. Model selection is based on iterative elimination from a wide diversity of plausible model formulations. Nonlinear weighted least squares method was utilised in estimation of the yield response models and dynamic programming was utilised in economic analysis. Our results suggest that fertiliser recommendations can be insufficient if soil phosphorus dynamics are ignored. Further, the optimal fertilisation rates for nitrogen and phosphorus, as well as the economic alternative costs of agri-environmental programmes depend on the soil texture of production area. Therefore, the efficiency of such programmes could be improved by targeting different fertilisation limits for different soil textures. In addition, uncertainty analysis revealed that the parameter uncertainty had a greater effect on the model output than the structural uncertainty. Further, the interaction of nitrogen and phosphorus fertilisers appeared to be a factor of relatively minor importance. The modelling approach and the model structure can be extended to other geographical areas, given that adequate datasets are available

Phosphorus and Nitrogen Yield Response Models for Dynamic Bio-Economic Optimization: An Empirical Approach

Nitrogen (N) and phosphorus (P) are both essential plant nutrients. However, their joint response to plant growth is seldom described by models. This study provides an approach for modeling the joint impact of inorganic N and P fertilization on crop production, considering the P supplied by the soil, which was approximated using the soil test P (STP). We developed yield response models for Finnish spring barley crops (Hordeum vulgare L.) for clay and coarse-textured soils by using existing extensive experimental datasets and nonlinear estimation techniques. Model selection was based on iterative elimination from a wide diversity of plausible model formulations. The Cobb-Douglas type model specification, consisting of multiplicative elements, performed well against independent validation data, suggesting that the key relationships that determine crop responses are captured by the models. The estimated models were extended to dynamic economic optimization of fertilization inputs. According to the results, a fair STP level should be maintained on both coarse-textured soils (9.9 mg L-1 a(-1)) and clay soils (3.9 mg L-1 a(-1)). For coarse soils, a higher steady-state P fertilization rate is required (21.7 kg ha(-1) a(-1)) compared with clay soils (6.75 kg ha(-1) a(-1)). The steady-state N fertilization rate was slightly higher for clay soils (102.4 kg ha(-1) a(-1)) than for coarse soils (95.8 kg ha(-1) a(-1)). This study shows that the iterative elimination of plausible functional forms is a suitable method for reducing the effects of structural uncertainty on model output and optimal fertilization decisions.Peer reviewe

A molecular-based identification resource for the arthropods of Finland

Publisher Copyright: © 2021 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this study, we (1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), (2) publish this library, and (3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi) at https://laji.fi/en/theme/protax. Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society.Peer reviewe

A molecular‐based identification resource for the arthropods of Finland

To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this paper, we 1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), 2) publish this library, and 3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1,000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi). Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society.peerReviewe