Study On Optimum Fertilization Technique For Mountain Apples Under The Measure Of Fertilizer Water Earthworm Pit

The hilly and gully area of the Loess Plateau in northern Shaanxi is an important production area for mountain apples in Shaanxi Province.In recent years,mountain apples have developed rapidly in Yan’an.The situation such as low soil nutrients and organic matter content,insufficient rainfall,and difficulty in irrigation has seriously affected the improvement of mountain apple yield and quality.How to improve the soil fertility of mountain apple orchards has become an urgent problem to be solved.In this study,under the measure of water collecting pit with fertilizer and earthworm,the effects of combined different organic and inorganic fertilizers on the soil moisture and nutrients,leaf nutrition,fruit quality and yield of mountain apple orchards were studied through field experiments,in order to explore the best fertilization mode to improve the soil fertilities of rain-fed mountain apples orchards and to promote the mountain apple production.The experimental treatments included control no fertilization（CK）,single application of chemical fertilizer（F）,cow manure+chemical fertilizer（CM）,mashroom residue+chemical fertilizer（MR）,cow manure and mashroom residue（1:1）+chemical fertilizer（CMMR）.The following main results and conclusions were obtained:（1）With the advancement of the apple growth stage,the soil water content shows a trend of"increasing first and then decreasing"with the increase of soil depth.Compared with CK,each fertilization treatment significantly increased the average soil water content of 0-200cm soil layer,of which showed CMMR>MR>CM>F>CK in all growth stages.The variation trend of soil water storage in 0-200 cm soil profile during different growth stages was basically as same as that of rainfall,and the trend of the soil water storage was presented as CMMR>MR>CM>F>CK in different growth stages.The average soil water storage capacity of 0-200 cm soil profile showed a trend of"increasing first and then decreasing".（2）All fertilization treatments increased the contents of soil organic matter,available nitrogen,available phosphorus,and available potassium to varying extent.Among them,the 0-20 cm top soil has the largest increase,followed by the 20-40 cm soil layer,and the40-60 cm soil layer has the smallest increase.In the 0-20 cm and 20-40 cm soil layers,the soil organic matter,available nitrogen,available phosphorus and available potassium content of the combined application of organic and inorganic fertilizers were significantly higher than those of the single fertilizer and no fertilizer control.In the 40-60 cm soil layer,the soil organic matter and available nitrogen content of the treatments with mashroom residue was significantly higher than that of the no fertilization control.Compared with single application of chemical fertilizers,combined application of organic and inorganic fertilizers could reduce the accumulation of nitrate nitrogen in the soil profile of 0-200 cm,increase the uptake and utilization of nitrogen by apple roots,and reduce the risk of nitrate nitrogen leaching into the deep layer,in which the effect of CMMR treatment was the best.（3）under the measure of the water collecting pit with fertilizer and earthworm,all fertilization treatments could improve the contents of total nitrogen,phosphorus and potassium content,and the appearance characteristics of the leaves at the different growth stages,and increase the yield and quality of apples to various extents.The combined application of organic and inorganic fertilizer was better than the single chemical fertilizers,in which the effect of CMMR was the best.The single fruit weight and yield of CMMR treatment reached as high as 242.36g and 51.55t·hm^-2,respectively,which were higher than that of other treatments.To sum up,under the measure of water collecting pit with fertilizer and earthworm,the mixed application of cow dung and fungus residue（1:1）+chemical fertilizer is the best fertilization combination for sustainable production of rain-fed mountain apple orchards,which is worthy to apply and extend in the loess hilly and gully area.