ISHS Acta Horticulturae 792: V International Symposium on Irrigation of Horticultural Crops
EFFECTS OF FERTIGATION MANAGEMENT ON CHINESE CABBAGE YIELD AND WATER AND NITROGEN LOSSES |
| Authors: | J. Doltra, J.M. Carpintero, F. Berbegall, C. Ramos |
| Keywords: | Brassica campestris L. ssp. pekinensis, irrigation, fertilization, water use efficiency, nitrate leaching |
| Abstract:
Nitrate leaching is a serious problem in areas of the Valencian community for vegetable production. The proportion of these areas dedicated to Chinese cabbage is small but has increased in recent years, and few studies have been done on this crop to assess the effects of fertigation on yield and water and nitrogen (N) losses. To investigate these effects a factorial experiment was set up with two irrigation rates: R1 (110% of ETc) and R2 (135% of ETc) combined with two levels of available soil mineral N (Nmin): 225 (N1) and 270 (N2) kg N ha-1. Nmin levels included the mineral N content in the 0-60 cm soil layer at planting time plus the N applied as fertilizer. Treatments were applied in a randomised design with four replicates. Plants were grown on ridges with two plant rows per ridge, and the dripper line in between the rows. Soil samples at 30 cm intervals down to 90 cm were taken before planting, at mid-growth, and at harvest, and mineral N and water content were determined. Ground cover, plant dry matter and N content were also measured several times along the growing season. Total yield, size classes and the economic value were determined. There was a statistically significant increase in yield and economic value with Nmin, but not with water application. The main effect of irrigation on the crop was to increase head size. ETc was 210 mm in all treatments, but drainage losses in the R2 treatments were about 10% higher than in the R1 treatments. The fertigation treatment with the highest water use efficiency (WUE) was that with irrigation at 110% of ETc with the high N level. Nitrate leaching ranged from 15 to 37 kg N ha-1 with no clear relationship with the fertigation treatments. We conclude that, under our conditions, irrigation with the calculated 110% ETc was enough to cover evapotranspiration requirements, and that the target value of Nmin in the 0-60 cm soil layer is at least 260 kg ha-1. | |
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