EVALUATION EFFECT OF APPLICATION METHODS OF DIFFERENT SOURCES OF HUMIC SUBSTANCES ON POTATOES PLANT GROWTH, PRODUCTIVITY AND QUALITY IN NEWLY RECLAIMED SANDY SOIL UNDER DIFFERENT LEVELS OF MINERAL FERTILIZERS

The present work was conducted to: evaluate the effect of application methods of CT, HA and FA individually or in combination without and with recommended mineral fertilizers doses (RMFD) (50 and 100%), on potato growth and their yields. To achieve these objectives, a field experiment during winter seasons of 2019 was conducted at El Nagah Village, El-Tahrir Region, El Beheira Governorate, Egypt (Latitude 30o.40 ́NLongitude 30o.33 ́E) (represented newly reclaimed sandy soil). The layout of the experiment was a splitplot design, with the main plots arranged in a randomized complete blocks design with three replicates. Potatoes (Solanum tuberosum L) plants cultivar Spunta, as a tuber crop. Three application methods of the used organic amendments were applying. These methods were: soil application (through drip irrigation "Drip"), foliar spray "Spray" and the alternative between them "Spray/Drip". The application methods of "Spray/Drip" was carried out by applying half amount of each organic amendments applying as soil application and the other 50% was applied as foliar spray). This study including the treatments of control (without any applications of organic amendments treatment). The used CT was added at a rate of 200 L fed -1 . FA and HA were added at a rate of 6 and 10 Kg fed -1 . respectively. The used mineral fertilizers (NPK) were applied at two rates (50 and 100% of recommended dose for the potato plants. After 40 and 65 days from sowing, dry matter yields (DMY) of the growing plants (shoots) and at harvesting, tuber yield per fed. " feddan=4200 m 2 "), as well as quality traits their elemental composition, mainly contents of nitrogen, phosphorus, potassium were determined. The obtained results indicated that, DMY (shoots and tuber) of potato plants received the combined application of CT+ HA+ FA were the highest values under all application methods compared to their individual application, under both levels of mineral fertilization, at 40 and 65 days after sowing for shoots as well as at harvesting for tubers. The maximum values of N, P and K contents of potato shoot at 40 and 65 days after sowing and in tubers were obtained from double application (Spraying/Drip ( method treatments of the in-combination treatments of organic amendments under both levels of recommended mineral fertilization. Accordingly, the duple application "Spray/Drip" methods of organic amendments, considered a more beneficial application methods in the cultivation of potato plants (Spunta cultivar) in newly reclaimed sandy soils due to it resulted in a high tuber yield, quality and reducing the environmental pollution as a result from reducing the additions of the mineral fertilizer with the in combination organic amendments.