IMPACT OF SUBSOILING, ORGANIC MANURE AND NITROGEN SOURCES ON SOME SOIL PROPERTIES AND SUGAR BEET PRODUCTIVITY

Abstract

A field experiment was conducted at the Experimental Farm of Sakha Agric. Res. Station, during the winter seasons (2014/2015 and 2015/2016) to evaluate the effect of subsoiling and organic manure combined with nitrogen fertilizer sources (ammonia gas and urea) on improving some soil physical and chemical properties as well as sugar beet productivity and N-uptake. The following findings can be summarized as follows: - The reduction of salinity after two years with subsoiling + urea, subsoiling + ammonia gas and subsoiling + compost + ammonia gas was 2.52, 2.52 and 3.02 dS/m, respectively compared to control. The corresponding values of ESP are 2.20, 2.06 and 2.59, respectively. Compost application was decreased soil salinity and sodicity. Reduction of salinity and sodicity were 0.69 dS/m and 0.79% with compost +urea and 0.63 dS/m and 0.88%, respectively with compost + ammonia gas compared to control. Nitrogen fertilizer sources (ammonia gas and urea) had no clear effect on salinity and sodicity in the soil. Subsoiling with and without compost are superior in enhancing soil bulk density and porosity. Average soil bulk density reduced from 1.31 g/cm3 with control to 1.16 g/cm3 after treatments application. Basic infiltration rate and cumulative infiltration are increased in the treated soils. The lowest values of basic infiltration rate (0.59 cm/h) and cumulative infiltration (6.28 cm) of soil were achieved under control, while the highest values (from 0.62 to 0.94 cm/h for basic infiltration rate and from 7.52 to 12.13cm forcumulative infiltration) under other treatments. Subsoiling are superior to compost in enhancing of quickly drainable pores (QDP), slowly drainable pores (SDP) and fine capillary pores (FCP)) of the soil. The lowest value of QDP (8.17%) and SDP (9.96%) and high percent of FCP (28.09%) are found with control. Treatments application increases QDP (from 9.76 to 13.38%) and SDP (10.47 to 15.36 %) and decreases FCP (24.56 to 17.86 %). Subsoiling and/or compost as well as nitrogen sources caused significant increases for root yield, juice quality, gross sugar and N-uptake of sugar beet. The increases of sugar beet roots yield are 1.58, 5.09, 2.68, 6.36 and 6.38 tonfed.-1 for compost +urea, subsoiling+ urea, compost+ ammonia gas, subsoiling+ ammonia gas and subsoiling +compost+ ammonia gas, respectively over than control in the first season.The corresponding values were 2.54, 5.26, 3.31, 6.41 and 6.72 tonfed.-1, respectively for the abovementioned treatments in the second season. Gross sugar yield and N-uptakewere parallel to the yield results in both seasons. The low value of N-uptake by root of sugar beet (average of 36.69 kgfed-1) was found with control, and the high values (varied from 40.10 to 52.16 kgfed-1) were found with treatments application in both seasons. Anhydrous ammonia injected gave higher rootyield and N-uptake of sugar beet than mineral nitrogen source (urea).