RESPONSE OF CHICKPEA AND MAIZE CROPS PLANTS GROWN IN A CLAYEY SOIL TO SURFACE AND SUBSURFACE DRIP IRRIGATION, BIOSOLID AND MINERAL NPK FERTILIZERS

Two field experiments were conducted during winter season 2006/2007 and summer season 2007 at the Farm of Sakha Agricultural Research Station, Kafr El-Sheikh Governorate to study the response of chickpea (Cicer arietinum) and maize (Zea mayes) crops to biosolids with different rates of mineral NPK fertilizers under surface drip and subsurface drip irrigation systems The design of the experiment was split plot with four replicates. Main plots were assigned to irrigation systems while subplots were assigned to biosolids (20 ton/fed.), zero, 50 ,75 and 100 % of the recommended  mineral NPK fertilizers (R D).
The obtained results revealed that irrigation methods , biosolid , mineral fertilizers and their  interactions have high significant effects on the grain yield and yield components of chickpea and maize crops. Surface drip irrigation produced the higher grain yields, 587.63 and 3872.6 kg/fed of chickpea and maize crops, respectively. Application of biosolid compost with  75 % NPK of (R D) resulted in the highest grain yield and yield components of chickpea and maize crops while surface drip gave higher grain N and K contents for the two crops while subsurface drip gave higher grain P content. The combination between biosolid and 100 %  NPK of (R D)  under surface drip irrigation result in the highest NPK contents 5.13, 0.63 and 10.74 ppm in grains of chickpea, respectively and 2.64, 0.71 and 3.93 ppm in grains of maize, respectively. The combination between biosolid and 100 %  NPK of (R D) under surface drip irrigation result in the highest Co, Pb and Ni contents 0.05, 0.06 and 0.19 ppm, respectively in grains of chickpea, respectively and 0.16, 1.52 and 0.45 ppm in grains of maize, respectively.Increasing the application rate of mineral fertilizers from 50  to 100% of (R D) with biosolid compost caused an increase in soil available NPK and available heavy metals under surface and subsurface drip irrigation. Application of biosoild compost increased  soil available heavy metals, soil salinity and organic matter under the two irrigation systems. Soil salinity values under subsurface irrigation were higher than those under surface drip irrigation. The amounts of water applied to chickpea and maize under surface drip irrigation (1126.60 and 2088.86 m³ /fed.), respectively were higher than the amounts applied (1058.36 and 2025.54 m³ / fed.) , respectively under subsurface irrigation. Application of compost with  75 % NPK of (R D) under subsurface drip irrigation resulted in the highest values of field water use efficiency for chickpea and maize (0.72 and 2.23 kg/m³), respectively. The periodic application of biosolid compost with a rate of 20 ton /fed. could save about 25 % of the mineral NPK fertilizers , maintain soil fertility and productivity level and a best means to recycling farm and human wastes for a clean environment.