RESUMO
To reveal the coupling effect of water and fertilizer on the yield of spring maize under shallow-buried drip irrigation in semi-arid area of western Liaoning, a field experiment was conducted with the quadratic regression orthogonal design of three factors (water, nitrogen and potassium) crossed with five levels in 2017-2018. A quadratic regression model was established with yield (Y) as the dependent variable and irrigation amount (W), nitrogen (N) and potassium (K) application amounts as independent variables to analyze the coupling relationships between Y and W, N and K, respectively. The results showed that the shallow-drip irrigation water-fertilizer coupling had significant impact on yield. The single factor of W, N and K promoted the yield, with their effects ranking as W>N>K. The effect of two-factor interaction on yield increased first and then decreased which ranked as WN>WK>NK. Considering the three-factor coupling effect on yield, the combination of abundant water, nitrogen and potassium was the highest, followed by high water, nitrogen and potassium, and low water, nitrogen and potassium the lowest. As the optimal treatments found by the model, we obtained the suitable water-fertilizer application range of shallow-buried drip irrigation with higher target yield of 8000-8810 kg·hm-2, that was, the irrigation amount was 43-61 mm, nitrogen 138-343 kg·hm-2 and potassium 79-163 kg·hm-2 under the ambient natural rainfall. The results provided a referable basis for application of water-fertilizer integrated cropping pattern under shallow-buried drip irrigation in semi-arid area of northern China.
Assuntos
Fertilizantes , Zea mays , Irrigação Agrícola , Agricultura , Biomassa , China , Nitrogênio , ÁguaRESUMO
The experiment was conducted using automatic rain shelter to study the effect of precisely controlled water quota of alternate subsurface drip irrigation (ASDI) on spring maize yield and water use efficiency (WUE). The results showed that jointing to heading stage and heading to hilling stage were the key stages of water requirement for spring maize under ASDI. In particular, both the water consumption percentage and diurnal water consumption in these two stages were higher than in other stages and were more sensitive to water deficit stress. The water demand in these two stages should be prioritized if irrigation was limited. Maize yield generally increased with the increasing irrigation quota. When the irrigation quota below 2764.5 m3·hm-2, the yield increased rapidly with the increasing irrigation quota. The yield increase then slowed down after the irrigation quota reached 2764.5 m3·hm-2. The maximum of maize yield of 12109.0 kg·hm-2 was obtained at the irrigation quota of 3357.1 m3·hm-2. Compared to fixed subsurface drip irrigation (FSDI), under the same irrigation quota, the yield, WUE and irrigation water use efficiency (IWUE) of spring maize in ASDI treatment were improved by 5.4%, 1.4% and 5.6%, respectively. Compared to FSDI, the maize yield in ASDI decreased by 1.8%, but its WUE and IWUE increased by 11.0% and 22.7% when the irrigation quota decreased by 20%. The optimal irrigation quota of ASDI for spring maize in the study area was1600.4-3357.1 m3·hm-2 by taking into account of yield and WUE.