American Journal of Plant Sciences, 2013, 4, 309-316 http://dx.doi.org/10.4236/ajps.2013.42041 Published Online February 2013 (http://www.scirp.org/journal/ajps) Effects of Farmyard Manure and Inorganic Fertilizer Application on Soil Physico-Chemical Properties and Nutrient Balance in Rain-Fed Lowland Rice Ecosystem Tilahun Tadesse 1* , Nigussie Dechassa 2 , Wondimu Bayu 3 , Setegn Gebeyehu 4 1 Amhra Region Agricultural Research Institute, Ethiopia; 2 Haramaya University, Ethiopia; 3 ICARDA, Ethiopia; 4 Ethiopian Institute of Agricultural Research, Ethiopia. Email: * tilahuntade@yahoo.com Received November 15 th , 2012; revised December 17 th , 2012; accepted December 25 th , 2012 ABSTRACT A field experiment was conducted to assess the effects of combined application of farm yard manure (FYM) and inor- ganic NP fertilizers on soil physico-chemical properties and nutrient balance in a rain-fed lowland rice production sys- tem in Fogera plain, northwestern Ethiopia. The study was carried out during the main cropping seasons of 2010 and 2011. Twenty-seven treatments comprising a factorial combination of three rates of FYM (0, 7.5, and 15 t·ha −1 ), three rates of nitrogen (0, 60, 120 kg·N·ha −1 ) and three rates of phosphorus (0, 50 and 100 kg·P 2 O 5 ·ha −1 ) were tested. The experiments were laid out as a randomized complete block design with three replications. Bulk density, organic matter content, and available water holding capacity, total N, and available P of the soil were measured just after harvesting the rice crop. Results showed that application of 15 t·FYM·ha −1 significantly increased soil organic matter and available water holding capacity but decreased the soil bulk density, creating a good soil condition for enhanced growth of the rice crop. Application of 15 tFYM·ha −1 increased the level of soil total nitrogen from 0.203% to 0.349%. Combined application of 15 t·ha −1 ·FYM and 100 kg·P 2 O 5 ·ha −1 increased the available phosphorous from 11.9 ppm to 38.1 ppm. Positive balances of soil N and P resulted from combined application of FYM and inorganic N and P sources. Applica- tion of 15·t ha −1 ·FYM and 120 kg·N·ha −1 resulted in 214.8 kg·ha −1 ·N positive balance while application of 15 t·ha −1 ·FYM and 100 kg·P 2 O 5 ·ha −1 resulted in a positive balance of 69.3 kg·P 2 O 5 ·ha −1 available P. From the results of this experiment, it could be concluded that combined application of FYM and inorganic N and P fertilizers improved the chemical and physical properties, which may lead to enhanced and sustainable production of rice in the study area. Keywords: FYM; Nitrogen; Phosphorous; Nutrient Balance; Rain-Fed Rice 1. Introduction Despite the past gains in rice production through chemi- cal fertilizers, recent observations of stagnant or declin- ing yields have raised concerns about the long-term sus- tainability of the crop production [1]. Continuous use of inorganic fertilizers leads to deterioration in soil chemi- cal, physical, and biological properties, and soil health [2]. The negative impacts of chemical fertilizers, coupled with escalating prices, have led to growing interests in the use of organic fertilizers as a source of nutrients [2, 3]. Organic materials such as FYM have traditionally been used by rice farmers [3]. FYM supplies all major nutrients (N, P, K, Ca, Mg, S,) necessary for plant growth, as well as micronutrients (Fe, Mn, Cu and Zn). Hence, it acts as a mixed fertilizer [1,4]. FYM improves soil physical, chemical and biological properties [1]. Im- provement in the soil structure due to FYM application leads to a better environment for root development [5]. FYM also improves soil water holding capacity [4]. The fact that the use of organic fertilizers improves soil structure, nutrient exchange, and maintains soil health has raised interests in organic farming [1]. The use of FYM alone as a substitute to inorganic fer- tilizer is not be enough to maintain the present levels of crop productivity of high yielding varieties [6]. Therefore, integrated nutrient management in which both organic manures and inorganic fertilizers are used simultaneously is the most effective method to maintain a healthy and sustainably productive soil [4]. Emerging evidence indi- cated that integrated soil fertility management involving the judicious use of combined organic and inorganic re- sources is a feasible approach to overcome soil fertility constraints [6]. The high cost of making inorganic fertil- izers accessible to farmers in Ethiopia, coupled with the * Corresponding author. Copyright © 2013 SciRes. AJPS