The present invention relates to biodegradable cross-linked alkyl polysaccharide dispersion materials for coating on lignocellulose sheets as a promising alternative to  traditional plastic mulch in sustainable agricultural practices and process for preparation thereof. More particularly, the present invention relates to biodegradable cross- linked alkyl polysaccharide dispersion coating material coated on lignocellulose sheets having tensile strength 15-20 MPa, tensile index of 25-30 N.m/g wherein the  coating dispersion material is obtained from the Michael addition reaction of polysaccharide (chitosan), acrylic crosslinker and further alkylation in presence of  alkylamine in 93%-95%yield. The aim of the invention is to mitigate environmental pollution and reduce dependence on non-renewable resources. The present  invention provides a method of coating to prepare water repellent lignocellulose sheet/paper with a stability of 50-70 days in outdoor environmental conditions and  biodegradation in soil within 30-45 days.