不同水肥条件对宁南旱地谷子产量、WUE及光合特性的影响

在宁南(海原)旱农试验区,通过谷子生育期补充灌水模拟当地不同降水年型,研究了不同水肥配合对谷子产量、水分利用效率(WUE)及旗叶光合特性的影响。结果表明:在欠水年型(不补灌)和平水年型(中补灌和高补灌)水分条件下,谷子产量和WUE的最高值均在中肥水平(N 120 kg/hm2,P2O5108 kg/hm2)时获得。然而,在欠水年型,从施肥增加当季作物产量和提高有限水分利用效率方面考虑,中肥水平的施肥量并不经济,而应适当减少施肥量,以节约农业生产成本,但从培肥地力的角度看,这种施肥水平是可取的。在丰水年型(高补灌)水分供应条件下,高肥水平(N 180 kg/hm2,P2O5162 kg/hm2)可使谷子产量达到最高,而中肥水平WUE却最高,因此,从提高旱作农田作物WUE和肥料利用效率角度看,施中等肥量更为合理。不同水肥条件通过改善土壤水分状况而改善作物净光合速率(P n)和蒸腾速率(T r),在水分亏缺的年份,作物受土壤水分胁迫严重,施肥对P n和T r的效应不明显;但当土壤水分供应状况较好时,P n和T r随施肥量的增加有增加趋势。

Effect of Different Water and Fertilizer on Yield,WUE and Photosynthetic Characteristics of Millet in Southern Ningxia Semi-arid Area

In Southern Ningxia(Haiyuan),through supplementary irrigation during key growth period of millet,the different patterns of annual rainfall was simulated.The effects of different water and fertilizer on millet yield,water use efficiency(WUE) and photosynthetic characteristics of flag leaves were studied.The results of experiment showed that,in the dry year(no supplementary irrigation) and normal year(low supplementary irrigation and mid-supplementary irrigation),the highest yield and WUE are the treatment of mid-fertilizer(N120 kg/hm~2,P_2O_5108 kg/hm~2).However,in the dry year,the quantity of fertilization should reduce properly because it's uneconomical in increasing yield and WUE of millet,which can save the cost.But to land improvement,this level of fertilizer is rational.In the humid year(high supplementary irrigation),the highest yield is obtained in the treatment of high-fertilizer(N180kg/hm~2,P_2O_5162 kg/hm~2),but WUE is the highest under mid-fertilizer.So,in order to improve WUE and fertilizer use efficiency,the mid-fertilizer is more rational than high-fertilizer.Through improving the soil moisture condition,net photosynthetic rate(Pn) and transpiration rate(Tr)of flag leaves are enhanced through coordination of different water and fertilizer.Under condition of soil water stress,the crop faced soil water stress seriously,the effect of fertilization in improving Pn and Tr isn't obvious,but when the soil moisture is sufficient,Pn and Tr improve with the increase of fertilizer correspondingly.