Abstract:

To study the effect of soil water and fertilizer management mode on orchard in dryland area,and to provide support and basis for optimizing water and fertilizer management and realizing the best matching of water and fertilizer in apple orchard.Put into use the three main modes that include integrated water-fertilizer and plastic mulching(T1),ridge film rainwater harvesting + straw mulching in ditch(T2),use fertilizer gun to integrate the fertilizer and water(T3),and conventional tillage fertilization(T4)were used as the comparison where in apple orchards of Gansu Province Longdong area.Measure and analysis the contents that the soil organic matter and mineral nutrition,chlorophyll and nutrient content in leaves and fruit quality in apple orchard.In different water and fertilizer management modes of apple orchards in dryland area.The contents of soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,total phosphorus,available phosphorus and available potassium showed a decreasing trend with the increase of soil depth from 0 to 60 cm,while the decreasing range gradually decreased.The contents of organic matter and mineral nutrients in shallow soil(0-20 cm)were significantly higher than those in middle and deep soil(20-60 cm). The content of soil total K was higher in different modes and layers.The results showed that the soil nutrients were enriched in shallow layer and the soil potassium was rich.In young fruit stage,fruit expansion stage and fruit maturity stage of apple,the decrease rates of the soil total nitrogen,total phosphorus and total potassium were significantly lower than those of available nutrient that the alkali-hydrolyzed nitrogen,available phosphorus and available potassium.The absorption and utilization efficiency of the soil mineral nutrients were different with different water and fertilizer patterns,while the nutrient consumption degree was also different,especially in shallow soil. In 0-20 cm soil depth,the content of soil organic matter in T4 treatment which the young fruit stage and fruit expansion stage was significantly higher than that in other treatments,while it was significantly lower at the fruit maturity stage.This showed that the clear tillage management(CK)had a low capacity of soil fertilizer conservation and nutrient sustainable supply.Under different water and fertilizer management modes,the chlorophyll contents which the young fruit stage and fruit expansion stage varied greatly,and the chlorophyll a,b and total chlorophyll content of T3 were significantly higher than those at T1 and T4 at young fruit stage. However, there was no significant difference with T2.There was no significant difference that the mineral nutrient content in leaves between different modes and different periods.The contents of total nitrogen,phosphorus on a downward trend with the growth and development of apple.While the potassium content in leaves showed an upward-downward trend.The contents of the nitrogen,phosphorus and potassium in leaves were the lowest at fruit maturity stage.The soluble sugar,total sugar and solid acid ratio of T2 were significantly higher than those of other treatments. The content of VC in T2 was significantly higher than T4,but not significantly different from T1 and T3.The application of "ridge film rainwater harvesting + straw mulching in ditch" technology can significantly improve water and fertilizer utilization efficiency and fruit quality in apple orchard in dry farming area.

Key words: Apple growth and development, Water and fertilizer management mode, Dry farming regions, Mineral nutrition