the effect of crop residue and different npk fertilizer rates on yield components and yield of wheat

introduction integrated nutrient management involving crop residue/green manures and chemical fertilizer is potential alternative to provide a balanced supply of nutrients, enhance soil quality and thereby sustain higher productivity. the present experiment was undertaken to evaluate the effect of different crop residue management practices and npk levels on yield components and yield of wheat. materials and methods field experiments were conducted during 2012-2014 at department of agronomy, chamran university. experiment was laid out in a randomized block designs in split plot arrangement. with three replications. crop residues were assigned to main plot consistent cr1: wheat residue; cr2: rape residue; cr3: barley residue; cr4: barley residue + vetch; cr5: wheat straw + mungbean; cr6: vetch residue; cr7: mungbean residue; cr8: no residue incorporation as main plot and three npk fertilizer rates: f1: (180n-120p-100k kg.ha-1); f2: (140n-90p-80k kg.ha-1); f3: (90n-60p-40k kg.ha-1) as sub plots. twelve hills were collected at physiological maturity for measuring yield components from surrounding area of grain yield harvest area. yield components, viz. number of spike per m2, seed per spike, 1000- grain weight, plant height were measured. grain and straw yields were recorded from the central 5 m2 grain yield harvest area of each treatment and harvest index was calculated. data were subjected to analysis by sas and mean companions were performed using the duncan multiple range test producer. also, graphs were drawn in excel software. results and discussion the result of analysis variance showed significant difference between crop residues for evaluated traits. the result indicated that the highest biological and grain yield was obtained when wheat treated with cr5: wheat straw + mungbean (green manure) and cr4: barley straw + vetch (green manure). biological and grain yield increased 31 and 26% respectively by cr5 comparing with control. the highest grain and biological yield resulted from the treated plants with f1 there was no difference among f2 and f1 fertilizer rate for grain yield of wheat. also cereal straw + legume (gm) in cr4 and cr5 treatments in f2 performed better than f1 fertilizer in no residue treatment and wheat grain yield under f2 × cr5 treatments was 25% greater than under f1 × cr8 treatments. the combined use of npk fertilizer plays an important role in wheat production. application of npk in balanced share at proper time has great impact on wheat yield. in order to achieve higher crop production, balanced and integrated nutrient supply and proper management of soil fertility is essential. application of crop residues/green manures along with suitable does of major nutrients for efficient growth of crop prevent the decline in organic carbon and also bridge up gap between potential and actual yield of wheat. further, use of crop residue had favorable effect on physic chemical and biological properties of soil due to supply of macro and micro-nutrients to crop properly. furthermore the decomposition and mineralization of crop residue is a slow process which could match the nutrient requirement of crop. the protein percentage, which is higher in cr5 and cr4 ,shows in whole crop residue treatments, the lowest valuable in f3 and improves with the increase in fertilization researching the highest value with the rate f1. no significant difference was observed between the rate f2 and f3; this would suggest a lower efficiency of the latter, at least for protein accumulation. increased wheat yield and component yield due to different crop residue incorporation and npk rate were reported by verhulst et al. (2011) and aulakh et al. (2012). conclusion application of (140n- 90p- 80k) kg.ha-1 and straw wheat along with mungbean and application straw barley + green manure was more effective than (180n- 120p- 100k kg.ha-1) application in no residue incorporation on grain yield and based on this research findings, the use of good quality crop residue, can achieve high yield while saving in npk fertilizer usage. the reaction yield is less affected by chemical input