arable fields
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Little is known of how the deep root systems of perennial crops contribute to deeper and better resource use when intercropped with annuals in arable fields. Therefore, we aimed at measuring the capacity of perennial deep roots, alfalfa (Medicago sativa L.) and curly dock (Rumex crispus L.) to access the nutrient source located under the neighboring annuals at 1.0 and 2.5 m of soil depth. Alfalfa and curly dock were able to access the tracer-labelled source placed at a distance under the annual crop strips. As a result, the reliance on deeper soil layer for nutrient uptake under intercroppings became greater compared with sole-croppings. Combination of an annual cereal (winter rye) and a perennial legume (alfalfa) with contrasting root systems exhibited higher resource complementarity compared with intercroppings having similar root systems or absence of legumes. Our results demonstrated that the deep-rooted perennials when intercropped with annuals can induce vertical niche complementarity, especially at deeper soil layers. This was assumed to be due to the vertically stratified root activity between the crop components, however, the magnitude of the effects depended on choice of crop combinations, and on types of tracers. Future studies should include estimates such as relative yield total and land equivalent ratio to quantitatively determine the effects of resource acquisition under annual-perennial intercropping in arable fields.

This article proposes a methodology for assessing the state of arable fields based on the use of Sentinel 2 satellite data. The essence of this methodology is cluster analysis of NDVI vegetation index profiles for a number of years, as well as expert analysis of the obtained results. The proposed method for assessing the state of arable fields has been tested on the example of arable lands of East Kazakhstan Agricultural Experimental Station LLP. This method can be used to optimize crop placement.

In nitrogen (N) -limited agricultural systems, a high microbial immobilization of applied fertilizer-N can limit its availability to plants. However, there is scarce information on the effect of the form of fertilizer used on the plant–microorganism competition in clay-rich soils under a severe semi-arid climate. In a field study, we investigated the wheat–microorganism competition after the direct application of NH415NO3 closely to seeds in arable fields in North Kazakhstan, documenting the effect of the use of liquid versus granular fertilizer and mini-tillage versus no-tillage. Our results barely showed any fertilizer-N translocation in the soil. Plants outcompete microorganisms for fertilizer-N during the vegetation period. Microbial-to-plant 15N ratios revealed a predominant fertilizer-15N uptake by plants. The strong competition for N was mainly related to the placement of the fertilizer close to the seeds. Moreover, the long time interval between fertilization and sampling enhanced the competition for N, meaning that previously microbially immobilized N became available to plants through the death of microorganisms and their subsequent mineralization. The fertilizer distribution between microorganisms and plants did depend on the form of fertilizer used, owing to the good solubility of granular fertilizer. The smaller fertilizer-N uptake under the no-tilling condition was probably due to the more intense soil compaction, which caused a reduction in plant growth. The application of fertilizer close to the seeds and the small fertilizer translocation during the vegetation period ultimately resulted in a high level of plant-N being derived from the fertilizer.

Small arable fields are beneficial with regard to ecosystem services, e.g., concerning biodiversity. By selecting appropriate crops and cultivation practices, arable fields can also be used as carbon sinks. The objectives of this study were to investigate what impact field conditions (e.g., field size and shape) and payments (subsidies) for environmental benefits have on profitability. A dynamic simulation model was used to simulate machine operations in fields of two different shapes and five different sizes (from 0.75 to 12.00 ha). A wide range of crops cultivated in Sweden were investigated (fallow land and plantation of Norway spruce were also included). A perimeter-based subsidy was suggested in order to conserve and promote biodiversity, and an area- and crop-based subsidy was suggested in order to promote sequestration of soil organic carbon (SOC). The results showed that, without financial support and from a purely economic point of view, most field types investigated should be planted with Norway spruce. With currently available subsidies, e.g., EU Common Agricultural Policy (CAP) direct payments, hybrid aspen, poplar, fallow, and extensive ley cultivation are the most profitable crops. Perimeter-based subsidies favoured the net gain for small fields. As expected, a subsidy for sequestration of SOC favoured cultivation of specific SOC-sequestering crops such as ley, willow, and poplar. Our recommendation for future studies is to investigate a well-balanced combination of perimeter-based support and SOC sequestration support that benefits biodiversity and climate under different cultivation conditions.

The goal of many agri-environment schemes (AES) is to increase biodiversity in agroecosystems. AES effects are often measured on invertebrates and birds; mammals as indicator species are infrequently targets of such researches. Our goal was to evaluate the local-scale effects of the Hungarian Agri-Environmental Measures (AEM) on the European brown hare (Lepus europaeus), which shows decreasing population trends across Europe. We compared hare abundances and their dropping numbers in AEM and control agricultural arable and grassland fields of 17 game management units in two seasons. We also examined the quality of arable fields based on their margin width and vegetation cover. We found that margin quality was higher in AEM than in the control fields. Control grasslands had higher vegetation quality than the AEM grasslands. We found a significant difference in hare counts between AEM and control arable fields in spring but no difference in autumn. The dropping densities did not differ in any season, treatment category or agroecosystem type. We conclude that the AEM program (2009-2014) in Hungary was not effective for the hare, and this might have been caused by the inadequate or weak application of AEM practices. We provide recommendations for future AEM programs to enhance biodiversity.