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Keywords: Applied Sciences
Agriculture & related technologies
Issue Date: 2010
Abstract: Wheat (Triticum aestivum L.) if cut before boot stage can be used for both forage and grain purposes, however it needs better nutrient management along with other agronomic practices to reduce the possible loss in grain yield. Experiments were conducted on imposing decapitation stress on wheat in comparison to no cut under different N levels and its application techniques to assess the crop response. The decapitation stress was imposed through cutting of foliage at 60 d after sowing. Three levels of nitrogen i.e. 100, 150 and 200 kg ha-1 were applied as full dose at sowing (M1), full dose at 2nd irrigation (M2) and split (M3) as half at sowing and half with 2nd irrigation to cut (C1) or no cut (C0) wheat. Treatments were arranged in randomized complete block (RCB) design with four replications having a plot size of 3 x 5 m2. The dry matter yield along with N concentration of different plant parts were determined at different growth stages to assess the translocation of photosynthate and N at these various stages. Wheat cultivar Fakhre Sarhad was planted on 1st November during both growing seasons with seed rate of 120 kg ha-1. All plots applied with recommended levels of 50 kg P2O5 and K2O ha-1. The experiment was conducted on silty clay loam alkaline soil (pH = 7.7-8.2) at Agricultural Research Farm (Malakandher), NWFP Agricultural University Peshawar during 2004-05 and 2005-06. The experimental site was located at 17o, 35 ́ N and 35o, 41 ́ W with altitude of 450 meters above sea level. Decapitation of wheat crop at early growth stage provided sufficient fresh forage but on the cost of reduced spikes m-2, grains spike-1, plant height, thousand grains weight, biological and grain yields when compared to no cut plants. However, harvest index remained same for both treatments. Cut treatment of wheat enhanced the N content at boot and anthesis stages but not at maturity. While grain and straw N contents, grain protein and nitrogen harvest index (NHI) were the same for decapitated and un-decapitated plots. Cut plants had lower N uptakes, apparent nitrogen re-translocation and its efficiencies compared to un-cut plants. Nitrogen use efficiency was increased with decapitation compared to no cut plants. Increased nitrogen fertilization either in split or late application as full dose had resulted in high N content at boot stage, anthesis, and maturity stage. Increasing N levels up to certain point had increased straw and grain N content, nitrogen uptake, grain protein content, nitrogen harvest index, apparent N re-translocation efficiency were increased, whereas NUE was reduced with increasing the N levels. Late application of N as full dose or even two equal splits applications at sowing and/or with 2nd irrigation had improved the N content , total N uptake, N re- translocation and its efficiency, grain protein, and NUE. However, the application time had no effects on N content and protein contents at maturity as well as NHI. Nitrogen fertilization had improved soil total nitrogen after harvesting the wheat. Days to emergence and emergence m-2 was not affected with fertilizer-N and its levels. Delayed boot stage was observed with fertilizer-N and its split application. Nitrogen fertilization as well as split application had increased spikes m-2, plant height and thousand grains weight. Increased N fertilization and full application or two equal splits had increased the grains spike-1, grain and biological yields, and harvest index. The dry matter of wheat stem, leaves and flag leaf at boot stage enhanced with fertilizer-N. The fertilizer-N increased stem and flag leaf dry matter at boot stage with increasing fertilizer-N level where no impact on leaves dry matter was observed. The two equal split doses improved stem and leaves dry matter, delayed full dose improved leaves dry weight while fertilizer-N timing had no influence on flag leaf dry matter. The decapitation stress increased stem and flag leaf dry weight but reduced leaves dry weight at boot stage. The dry matter of stem, leaves, flag leaf, peduncle and spike improved with fertilizer-N at maturity compared to control. The increasing fertilizer-N levels had no influence on stem, leaves and flag leaf dry matter but enhanced peduncle and spike dry matter at maturity. Fertilizer-N timing had no impact on stem, spike, leaves and peduncle dry matter at maturity while only flag leaf dry matter improved with full delayed dose of N application. The decapitation stress reduced leaves, stem, flag leaf, peduncle and spike dry matter at maturity. On the basis of economic analysis optimum VCR (value cost return) and relative increase in income (RII) obtained with 150 kg N ha-1 split application. Where additional Rs. 4959 ha-1 as net income over control were obtained with decapitation of wheat crop. Keeping in view the results two equal split doses 150 kg N ha-1 at sowing and 2nd irrigation is recommended for higher grain yield and economic return.
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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