EFFECTIVENESS OF NATURAL SOIL CONDITIONERS AND IRRIGATION REGIME ON: 1- LOAMY SAND SOIL PROPERTIES, CROPS PRODUCTION AND WATER PRODUCTIVITY

Abstract

Two field experiments were carried out at loamy sand soil, located at Baltim district, Kafr El-Sheikh Governorate. The experiments were occupied for conducting wheat and maize during winter and summer seasons of 2015/2016 and 2016 respectively. The main objectives of this investigation were to study and evaluate the effect of soil conditioner types, and their mixtures in sandy soil subjected to different irrigation deficits on the following parameters: (i) soil properties (chemical, physical and moisture constants, and (ii) agronomical production of wheat and maize and water productivity after full maturity in the studied soil under consideration. Four types of soil conditioners [bentonite, compost, polyacrylamide and their mixtures 1:1:1(w/w)] were applied before cultivation. Three levels of soil moisture depletion regimes were used (30, 50 and 70 %) from its available water capacity. Applying natural soil conditioner types, and their mixtures in the studied sandy soil subjected to moisture depletion regime realized improving soil chemical, physical and moisture content. Soil salinity (soil reaction, electrical conductivity and ionic strength), hazard sodium parameters (soluble sodium percentage and sodium adsorption ratio), soil porosity and available water capacity were increased. On the other hand, hydraulic conductivity and bulk density were decreased. Polyacrylamide treatment realized the superiority under wheat and maize field experiments. Irrigation after 50 % AWSMD gave moderate values of such properties between wet (30% AWSMD) and dry (70% AWSMD). Increasing grains, straw, grains weight and harvest index significantly for wheat and maize crops, because of adding soil conditioners compared with control. Results also indicated that, from view point of water and economic, the highest values of crop yield and water productivity were obtained from irrigation at 50 % depletion from its available water capacity rather than 30 % and 70 % respectively.