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A new, ridge-furrow-ridge rainfall harvesting (RFRRH) system covered with black polyethylene (PE) mulch and black perforated PE mulch was studied in the cultivation of purple coneflower (Echinacea purpurea Moench). In the RFRRH system, PE mulch covered two ridges and a furrow between them, which serve as a rainfall harvesting zone. Soil water content, crop yield and production cost effectiveness were evaluated. We conclude that the new RFRRH system could reduce yield and increase material costs, which results in reduced income per hectare. On the other hand, the RFRRH system reduced weed control time and may therefore increase profit per hectare. It supplies at least an equal amount of water in comparison to bare ground (control), and can be used in semi-humid or humid regions without additional irrigation. Copyright

The impact of organic fertilization and the level of mineral nitrogen fertilization on organic nitrogen and humus balance was studied in a long-term field experiment IOSDV Jable in central Slovenia (sub-Alpine climate, average annual precipitations 1345 mm, average annual temperature 9.58C, heavy hydromorphic silty loam, umbric Planosols). During the period 1993-2010, precipitation increased significantly at an average rate of 19 mm a 71 ; over the same period, average annual temperature increased by 0.0258C (l.f.). The increase in annual precipitation had a negative impact on the yield of all crops (maize, wheat and oats). Increases in mineral N rate led to increased yields. At the highest mineral nitrogen rate, farmyard manure (FYM) did not have a positive impact on yield in the investigated crops, although there was a positive effect of straw incorporation on the yield of maize and oats, and a negative impact on the yield of winter wheat. The organic carbon (Corg) level in the soil increased for all treatments, including FYM or straw and mineral N fertilization. The N content in the soil decreased in the treatment with no organic fertilization and no mineral N, and in the treatment with straw and no mineral N. Corg was increased in treatments with organic fertilization and the highest N rates and remained the same in treatments with moderate N fertilization. All C balances were negative.

In Central Slovenia within a long term static experiment IOSDV we investigated the impact of mineral nitrogen (N) fertilisation (0, 65, 130, 195 kg/ha) on the N content and the N amount in winter wheat (larger roots, stems, spikes and leaves) in EC 81/82 and EC 90/91, employing three systems of management: farmyard manure ploughing in before forecrop maize, straw ploughing in and green manure, no organic fertilisation. At EC 81/82 the N content in larger roots was around twice as high as the N content in stems and around twice as low as the N content in spikes and leaves. There was 80% of the whole N amount in plant located in the spikes and leaves (33–168 kg/ha) in EC 81/82 and 90% in EC 90/91. Calculated N recovery from mineral fertiliser was 68–87%; it increased with the increasing N rates in the system with farmyard manure ploughing in and in the system with no organic fertilisation, but not in the system with straw ploughing in and green manure. Between EC 81/82 and EC 90/91 wheat gained from 4 to 34 kg N/ha, but there were more important translocations of N inside the plants, which were higher at higher mineral N rates. There was a significant impact of management system on the N uptake at the highest mineral N rate.

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