Abstract This study aimed to confirm the causality of climatic and soil physical factors on silage corn yield based on the climatesoil-yield network in Korea. The climatic variables were growing degree days, high temperature, low temperature, surface temperature, rainfall, relative humidity, wind speed, and sunshine duration before and after silking. The soil physical variables were the effective depth, slope and drainage class of the soil. The yield variables were total digestible nutrients, dry matter and fresh matter yields. The network was constructed using structural equations and neural network models. In the result of the network, three causalities were remarkable. First, all longitudinal climatic causality before and after the silking stages were significant. It implies that the effect of climate in the vegetative stage reaches to yield through themselves in the reproductive stage. Second, there was the causality between climatic and soil physical factors based on indirect effects. Thus, it is likely to lead to an offset between the direct and indirect effects of soil physical factors. Finally, the effects of drought and heavy rainfall were clear before and after silking stages, respectively. It indicates that stress can damage the corn yield for silage. Here, the damage caused by the drought could be recovered due to various indirect effects, while the damage caused by heavy rainfall was fatal because there was a lack of an indirect path to recover from. This study contributed to identifying how various climatic and soil physical factors can affect production in the network. Furthermore, the climate-soil-yield network for silage corn in this study will help extend the structure with various factors in future studies.

Abstract Hemp (Cannabis sativa L.) is one of the traditional crops currently being newly re-introduced in Slovakia and cultivated for multi-purpose uses, while still there is a lack of crop biomass yield data. The main objective of the paper is to document the yield of aboveground biomass of selected cultivars of hemp ('Bialobrzeskie', 'Felina', 'Santhica', 'Epsilon', and 'Futura'), which were tested in the pilot open-field experiments conducted during 2009 − 2012, immediately after a wave of legislative changes. The trial was agronomically designed including three nitrogen treatments as follows: (i) T1 30 kg N/ha (the full 30 kg/ha in the phenophase BBCH 31), (ii) T2 60 kg N/ha (dividing on 30 + 30 kg/ha in the phenophase BBCH 31 and 51, respectively), and (iii) T3 90 kg N/ha (dividing on 30 + 30 + 30 kg/ha in the phenophase BBCH 31, 51 and 59, respectively); whereas NPK 15-15-15 in the dose of 200 kg/ha was applied before the sowing all across the treatments. The total average dry matter (DM) yield of 9.49 t/ha was achieved, ranging from 2.12 to 16.80 t/ha. DM yield was affected mainly by years (F-ratio 337.40, P-value 0.0000), followed by nitrogen treatment (F-ratio 47.86, P-value 0.0001), then by cultivars (F-ratio 22.37, P-value 0.0019) and finally by replications (F-ratio 0.65, P-value 0.58). However, the need for further studies aimed to quantify more precisely the response of the cultivars to the weather and soil conditions is necessary, especially the cultivars of new and foreign origin.

Abstract Ambrosia artemisiifolia L. (Asteraceae) has become a major threat to agriculture in many parts of the world. Global agriculture relies on the use of herbicides against A. artemisiifolia in the crops most at risk – sunflower, maize and soybean. This paper aims to provide an overview of the chemical control of A. artemisiifolia and to summarize the latest knowledge in this field. The sunflower is the crop most threatened by A. artemisiifolia, as both plants belong to the same family. The best control level was achieved after the preemergence application of flurochloridone and the combination of dimethenamid-P + pendimethalin. The introduction of the non-GM Clearfield and ExpressSun technologies allowed effective control with postemergence herbicides in sunflower varieties tolerant to imidazolinone and tribenuron-methyl herbicides. In soybean, the highest efficacy was observed in trials with imazamox and bentazone alone and in combination. The combination of imazamox with bentazone had a positive effect on yield compared to untreated stands. The introduction of transgenic soybeans tolerant to glyphosate led to increased glyphosate use and the predictable emergence of weed resistance in America in 1996. Preplant followed by postemergence herbicides were critical for the effective control of glyphosate-resistant A. artemisiifolia in glufosinate tolerant soybean. In maize, the highest efficacy was obtained after the application of glufosinate, bromoxynil and mesotrione + atrazine. Of the above substances for the control of A. artemisiifolia in maize, only mesotrione is currently registered in the EU.