Effect of Various Level of Nutrient Application on Yield and Yield Attributing Characters of Wheat at Deharadhun, India

Wheat (Triticum aestivum L.)is the major staple food crop of the world. It is used as a staple food by about 10 million peoples allover the world mainly in the 43 countries and contributes 30% to overall grain demand of the world. It provides around 20% of the aggregate food calories to mankind (Redddy, 2004) having maximum protein as compared to other cereals. In India, wheat is cultivated over an area of 28.17 million hectare with a production and productivity of 73.70 Mtand 26.17 qha-1, respectively (Anonymous, 2007). It contributes 35% of the total food grain production of the country. India alone produces 13% of world’swheat (Anonymous, 2007).

There are many factors responsible for low yield of wheat including improper application of nitrogen fertilizer or no application of nitrogen fertilizer, edaphic properties, biotic properties, availability and distribution of irrigation, prevailing climatic conditions, improper field management and lack of adequate farmer'sknowledge and awareness. Firstly nitrogen is one of the major nutrients which play important role for metabolic process of the plant for bumper yield when it applied inappropriate amount. All the biochemical process occurring in the plants are mainly governed by nitrogen and its associated compounds, which make it essential for growth and development of wheat (Kutman et al., 2011). Therefore it is necessary to apply nitrogen fertilizer in the soil to get bumper yield of wheat (Ali et al., 2000). Secondly phosphorus play vital role for plant development starting as wheat is just a seedling and continuing all the way to maturity. Apart from formation of quality seeds, this nutrient ensures uniform heading, faster maturity and strengthens the plant to survive during the winter. The most noticeable symptoms are stunted growth, stems and leaves turn purple, reduced root system and poor tillering are common symptoms when deficiencies are observed, winter wheat is more susceptible to winterkill and vulnerable to disease pressure, among other plant health issues and finally wheat requires potassium for optimum growth and development. Adequate potassium results in superior quality of whole plants due to improved efficiency of photosynthesis, increased resistance and greater water use efficiency and sufficient potassium results in stronger wheat straw and assists ingrain filling. Nitrogen is the most important element to achieve stable high grain yields and growth it is essential for improving grain quality of wheat. In order to get high yield and good and stable quality of wheat N fertilizer rates, split N application and timing of application have been the major strategies recommended to increased protein content and improved oleograph parameters (Shejbaloval et al., 2014). Phosphorus is the second to nitrogen as the nutrient that most commonly limits wheat growth and development. Phosphorus has been the subject of more fertility investigation than any of the other essential elements. Soil phosphorus (P) deficiency is a major constraint to increased crop yields in many areas of the world (Vance et al., 2003). The production of less photosynthetic assimilates and reduced assimilate transport out of the leaves to the developing fruit greatly contributes to the negative consequences that deficiencies of potassium have on yield and quality production (William, 2008). Saini et al (2010) reported that recommended dose of fertilizer may have supplied nutrients to crop in optimum and balanced proportion required for its better growth and development, thereby leading to higher grain yield. The combined application of N, P and K has proved to be more effective in increasing yield of wheat as compared to sole application of either Nor P or K (Petkov, 1983).

Application of imbalanced or excessive nutrients led to declining nutrient use efficiency and making fertilizer consumption uneconomical and producing adverse effects on atmosphere and groundwater quality causing health hazards and climate change (Aulakh et al., 2009). Keeping this in view the present experiment was conducted with the following objectives:  To study the effect of different NPK levels on growth and yield of wheat under normal practice and system of wheat intensification.  To study the effect of different nutrient levels on flowering and maturity of wheat crop.  To workout relative economics of different levels of NPK.