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Apr 14, 2017

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INTEGRATED EFFECT OF BIOCHAR AND PK FERTILIZER ON MAIZE YIELD AND SOIL PEROPERTIESINTRODUCTIONMaize is an important summer cereal crop grown in Pakistan. At national level during 2008- 2009 the total area under maize cultivation was 1051.7 thousand hectares with a total production of 3604.7 thousand tons and average grain yield of 3427 kg per hectare. The figures in Khyber Pakhtunkhwaare 509 thousand hectares with a total production of 903.9 thousand tons and average yield of 1776 kg hectare-1 (MINFAL, 2006). Maize is multipurpose cereal crop that provides food for human, feed for animals, and raw material for the industries (Khaliq et al., 2004). In developing countries, maize is consumed directly and serves as staple diet for about 200 million people. However, in processed form it is used as fuel (ethanol) and starch. Starch in turn involves enzymatic conversion into products such as sorbitol, dextrine, sorbic and lactic acid, and appears in household items such as beer, ice cream, syrup, shoe polish, glue, fireworks, ink, batteries, mustard, cosmetics, aspirin and paint (Plessis, 2003).Maize is one of the most important sources of edible oil. Our country spends a huge amount of foreign exchange every year to import edible oil. Starch is the main product of maize for which dextrin, liquid glucose, solid glucose, powder glucose and crystalline dextrose are prepared (Masood et al., 2011).Maize is an exhaustive crop having higher potential than other cereals crops to consume large quantity of nutrients from the soil during growth (Chen et al., 1994). Intensive cultivation, growing of exhaustive crops, use of imbalanced and inadequate fertilizers accompanied by restricted use of organic manures have made the soils not only deficient in the nutrients, but also deteriorated the soil health, productivity is largely dependent on nutrient management. Maize needs fertile soil to express its yield potential. Additions of organic manure not only supply the plant nutrients but also improve soil health (Kannan et al., 2013).The reduction of maize yields is a result of reduced fertilizer application and nitrogen use efficiency. Degraded soils have reduced mineral availability as a result of reduced cation exchange capacity. These soils have low pH levels and as a result large amount of nutrient loss especially nitrogen through leaching. The soils are generally becoming sandy with reduced organic matter content (Cushion et al., 2010)Biochar is a fine-grained, carbon-rich, porous product remaining after plant biomass has been subjected to thermo-chemical conversion process (pyrolysis) at low temperatures (350600C) in an environment with little or no oxygen (Amonette and Joseph, 2009). Biochar is composedof, sulphur (S), hydrogen (H), nitrogen (N), oxygen (O), carbon (C)and ash in different proportions (Masek, 2009). The important quality of biochar that makes it attractive as a soil amendment is its highly porous structure; potentially responsible for improved water retention and increased soil surface area (Arias et al., 2008). Biochar addition to agricultural soils can improve soil fertility, with the added bonus of climate change mitigation through carbon sequestration (Cornelissen et al.,2013). Conversion of biomass into biochar stabilizes the carbon (C) that is then applied to soil; diminish increased levels of CO2 in the atmosphere. Biochar contains high concentrations of carbon that is recalcitrant to decomposition, so it may stably sequester carbon (Glaseret et al., 2002). Biochar amendments alter soil physical properties (Venterea, 2008). Addition ofbiochar to soils improves soil fertility and thus increase crop yield of agricultural lands (Marris, 2006; Chan et al., 2007). Application of biochar has beneficial effects on soil properties like increased water holding capacity, enhanced cation-exchange capacity (CEC), higher pH, increased water retention, reduced leaching of nutrients and adding nutrients by itself (Lehman & Joseph, 2009).Biochar application increases crop yields of maize (Kimetu et al., 2008).Biocharhas the potential to improve soil quality, crop yield and to expand terrestrial soil carbon pool (Palumbo et al., 2009). Biochar added in the soil can increase microbial activities (Pietikainenet al., 2000). Biochar application to soil helps in several ways: less fertilizer is needed because biochar absorbs and slowly releases nutrients to plants,biochar improves soil moisture retention and conserves water, securing the crops against drought and reduces the methane emissions from paddy. It increases the soil microbes and decreases the bulk density of soils. It supports better growth of roots and helps in reclamation of degraded soils (Cushion et al., 2010).Phosphorus is one of the most important nutrients for higher yield in larger quantity (Chen et al.,1994) and controls mainly the reproductive growth of plant (Wojnowska et al., 1995). P is the second most crop-limiting nutrient in most soils. It is needed for growth, utilization of sugar and starch, photosynthesis, nucleus formation and cell division, fat and albumen formation. Energy from photosynthesis and the metabolism of carbohydrates is stored in phosphate compounds for later use in growth and reproduction (Ayub et al., 2002). It is readily translocated within the plants, moving from older to younger tissues as the plant forms cells and develops roots, stems and leaves (Ali et al., 2002). Adequate P results in rapid growth and earlier maturity and improves the quality of vegetative growth.It is a fundamental nutrient for plants, because it plays a vital role in many physiological and biochemical processes (Mathews et al., 1998). It is a structural component of nucleic acids, many co-enzymes, phospho-proteins and phospho-lipids (Ozanne, 1980).Potassium (K) is an essential nutrient for plant growth and cannot be replaced by other elements. The function of potassium is associated with increased root growth and tolerance to drought, cellulose formation, enzyme activity, photosynthesis, transportation of sugar and starch. It also increase protein content of plants, maintain turgor, reduce water loss, and to protect plants against diseases and nematodes (Thomson, 2008). In Pakistan most of soils contain relatively large amounts of total K, however only a small fraction is present in available form to plants. Most of the soils have

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