TILLAGE, NITROGEN AND RESIDUE MANAGEPMENT STRATEGIES IN WHEAT (Triticum aestivum L.) GROWN UNDER RICE BASED SYSTEM

Abstract

Wheat is a major staple food of Pakistan, which not only provides the food for human but also has an important role in livestock feeds. It provides the raw material to various agro- based industries. Average wheat yield of the country is 2.7 metric t ha -1 (Govt. of Pakistan, 2010-11). Conventional methods of planting, late planting, poor management practices and imbalanced nutrient management are the major constraints of low yield in wheat production at farmer’s field. Zero tillage technology is considered more convenient and efficient planting system as it saves irrigation water, cost of inputs and increased the net income. Pakistani soils pH is high and productive without any major problem for crop husbandry. It is medium in K 2 O and deficient in N, P 2 O 5 and organic matter. Research was conducted at University of Agriculture, Faisalabad, Pakistan, to evaluate the different tillage systems along with nitrogen levels and mulch materials regarding yield, growth, soil physical properties and grain quality. The aim of experiment was to determine the most favorable tillage system along with the best nitrogen level and mulch material. Two studies were carried out during 2009-10 and 2010-11. First study comprised of four tillage systems; conventional tillage, deep tillage, zero tillage sowing with zone disc tiller and zero tillage sowing with happy seeder along with four nitrogen levels i-e 75 kg ha -1 , 100 kg ha -1 , 125 kg ha -1 and 150 kg ha -1 along with control. The study-2 comprised of same tillage systems along with four mulch materials i-e rice straw, wheat straw, plastic sheet @ 4 t ha -1 , natural mulch along with no mulch. Split plot design with three replications having net plot size 8.0 m x 5.4 m. Wheat variety Sehar-2006 was sown 22.5 cm apart with seed rate of 125 kg ha -1 having 24 rows per plot. Data pertaining to growth, yield, soil physical properties and grain quality were noted by using standard procedures. Data collected from both experiments were statistically analyzed by MSTATC and the differences among the treatment means were compared for significance by using the Duncan’s New Multiple Range Test at 5% level of probability. The computer package MS-Excel was used to prepare the graphs. In 2010-11, the climatic conditions were favorable for crop growth, production and overall 24 % greater grain yield produced than 2009-10 in first experiment. Higher grain yield was produced in deep tillage and happy seeder as compared to other tillage systems while N 125 kg ha -1 generated higher grain yield than all nitrogen levels during both the years. In both the year’s deep tillage and N 125 kg ha -1 gave maximum LAI and TDM than other tillage systems and nitrogen levels. Higher root length was recorded at deep tillage and N 125 kg ha -1 in comparison to all tillage systems and nitrogen levels both the years of study. During both the years’ soil bulk density was 10-20 % lower in deep tillage than all tillage systems at flowering and harvesting stage at 0-5 and 5-10 cm soil depth. Nutrient use efficiency was 44 % higher in deep tillage compared to all tillage systems. During both the years higher water use efficiency 7 to 10 % was noted at deep tillage and happy seeder compared to all tillage systems while N 125 kg ha -1 led to 53 % higher WUE. Higher grain protein content was observed at deep tillage and 5-40 % at N 150 kg ha -1 than other tillage systems and nitrogen levels during both the years. All the tillage systems in both years gave maximum net rate of return and benefit cost ratio were noted at N 125 kg ha -1 . In 2009-10 maximum marginal rate of return 498 % and 577 % were noted in conventional tillage and deep tillage at N 75 kg ha -1 while 545 % and 508 % in zone disc tiller and happy seeder at N 100 kg ha -1 . Maximum marginal rate of return in all tillage systems were noted at N 100 kg ha -1 during second year. xxIn second study 14 % greater grain yield was attained in 2010-11 than 2009-10. In both the years of study deep and happy seeder gave higher grain yield than other tillage systems while plastic mulch @ 4 t ha -1 produced higher grain yield than other mulch materials. During both the years higher LAI and TDM were observed at happy seeder and M Plastic @ 4 t ha -1 . Soil bulk density at deep tillage was 10-15 % lower than other tillage systems while plastic mulch materials @ 4 t ha -1 at 0-5 cm gave 4-10 % lower bulk density during both the years of study. During both the growing seasons higher water use efficiency 2 to 7 % was noted at deep tillage compared to all tillage systems while plastic mulch @ 4 t ha -1 gave 2 to 24 % higher WUE. In 2009-10 and 2010-11, higher grain protein content was noted at deep tillage and M Plastic @ 4 t ha -1 compared to all tillage systems and mulch materials. Conventional tillage and deep tillage during first year gave maximum net rate of return and benefit cost ratio at M Rice @ 4 t ha -1 while zone disc tiller and happy seeder gave at M Natural (Heavy Planking). In second year all tillage systems gave maximum net rate of return and benefit cost ratio at M Rice @ 4 t ha -1 . All tillage systems gave higher marginal rate of return at M Natural in first year. During 2010-11, higher marginal rate of return was recorded in conventional tillage, deep tillage and zone disc tiller at M Natural while happy seeder gave higher marginal rate of return at M Rice @ 4 t ha -1 . In light of above results, it is recommended that in rice-wheat cropping system, happy seeder and deep tillage with N 125 kg ha -1 application gave higher grain yield. While in case of mulch materials, happy seeder and deep tillage produced maximum yield when natural mulch was applied. On the bases of marginal rate of returns, it is recommended that the resource poor farmers should grow wheat with happy seeder and deep tillage alongwith N 100 kg ha -1 , while the progressive farmers may fertilize wheat with N 125 kg ha -1 to obtain higher net field benefits. In case of mulch, it is recommended that the resource poor wheat growers should grow wheat with happy seeder and deep tillage at M Natural , while the progressive farmers may grow wheat with M Rice @ 4 t ha -1 to get higher net field benefits. The fertility status of Pakistani soil is low due to warm climate and extensive cropping systems. Currently, farmers do unwise wheat tillage operation. So, it is strongly recommended that farmers should adopt zero tillage technology alongwith above recommendation of nitrogen fertilizer and mulch. It would helps to reduce cost of production and and increase yield. Subsequently, it increases farmer’s profit, improves his livelihood and eventually helps to reduce poverty.