tillage and nitrogen management impact on maize - The University of ...

Sarhad J. Agric. Vol.26, No.2, 2010

TILLAGE AND NITROGEN MANAGEMENT IMPACT ON MAIZE IMTIAZ AHMAD*, MOHAMMAD TARIQ JAN** and MUHAMMAD ARIF** * **

Cereal Crops Research Institute, Pirsabak, Nowshera – Pakistan. Department of Agronomy, NWFP Agricultural University, Peshawar – Pakistan.

ABSTRACT Tillage system and fertilizer-N management are needed to improve sustainable maize production. The objective of the study was to investigate the impact of conventional tillage and no tillage systems, nitrogen rates and its application at various growth stages on maize production. Experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera, Pakistan, for two consecutive years (2004-2005) in a randomized complete block design with split plot arrangement having four replications. Each experiment consisted of two tillage systems i.e. no tillage (NT) and conventional tillage (CT), three levels of nitrogen fertilizer (60,120 and 180 kg ha-1) and nitrogen application at various growth stages. The combination of tillage systems and nitrogen levels were allotted to main plots while nitrogen application at various growth stages to sub plots. More grains ear-1 was observed in CT as compared to NT. The number of grains ear-1 remained at par when N level was increased from 60 to 120 kg N ha1 but further increase in N level to 180 kg N ha-1 resulted in significant increase in grains ear-1. Number of grains increased when N was applied in split doses as compared to the full (sole) application at sowing or knee high stage and were higher when applied in two splits than three split doses. Heavier grains were produced in CT as compared to NT and with split application of N as compared to sole. Conventional tillage also produced significantly higher grain yield as compared to no-tillage. Year as a source of variation had significant impact on thousand grain weight, grains ear-1 and heavier and more grains were produced during 2004. Significant interaction among tillage and N was observed for grains ear-1, grain weight and grain yield. Conventional tillage produced higher grains ear1 and heavier grains even with lower dose of 60 kg N ha-1, while no till required 180 kg N ha-1 to deliver the same results. Grain yield was highly responsive to increase in N fertilizer up to 120 kg N ha-1 under conventional tillage system. Further increase up to 180 kg N ha-1 merely induced any increase in grain yield under CT. In case of no till grain yield decreased beyond 120 kg N ha-1. Conventional tillage proved superior in terms of grains ear-1, grain weight and grain yield as compared to no till. Grain yield increased up to 120 kg N ha-1 but grains ear-1 and grain weight were higher at the highest dose of 180 kg N ha-1. Split application of N significantly increased all parameters including yield and yield components as compared to full application of N in single dose. Key Words: No-tillage, conventional tillage, nitrogen levels, growth stages and yield Citation: Ahmad, I., M.T. Jan and M. Arif. 2010. Tillage and nitrogen management impact on maize. Sarhad J. Agric. 26(2): 157-167. INTRODUCTION Maize (Zea mays L.) is the third most important cereal grain crop in Pakistan, after wheat and rice. Maize is primarily grown as a summer crop in a variety of agro-climatic conditions throughout the province. It is successfully grown at an altitude from 1500 meter above sea level in plains to as high as 3300 meter above sea level in the highlands from 50oN to 40oS latitude as multi-purpose crop in temperate and subtropical regions of the world (Ihsan et al., 2005). It is grown on about 27% of the total cropped area annually in the North West Frontier Province (NWFP) of Pakistan (Khan et al., 2004). It is grown on about 0.492 million hectares with a total production of 0.782 million tons and average yield of 1.590 tons ha-1 (MINFAL, 2005-06). Maize is both the primary crop in majority of the farming systems and the staple food of the rural population in much of the province, especially mountain areas (Khan et al., 2003). In high mountains of the province where chilling conditions and snowfall limit the growing period of other cereals, it has priority to be a food crop due to short duration status (Saeed and Saleem, 2000). Research throughout the world is providing increasing evidence of the value of producing corn without tillage. With most soil and rotations, yields and profit from no-till corn production are similar to or even exceeds in some cases to those of conventional tillage. Reduced soil erosion has always been a convincing argument for no-till production. Yet some management problems persist, limiting acceptance of the practice. The broad spectrum of herbicides now available has eased some of the challenging weed control problems in no-tillage (Gangwar et al., 2006). Tillage systems are an integral part of crop production affecting numerous factors important to crop growth. Recently a shift towards conservation tillage system has occurred for a variety of reasons, including soil water

Imtiaz Ahmad, et al. Tillage and nitrogen management impact on maize…

158

conservation, fuel energy saving and erosion control (Torbet et al. 2001). For these reason efforts have been undertaken to develop conservation tillage system. Tillage operation and soil disturbance generally can cause an increase in soil aeration, residue decomposition, organic N mineralization, and the availability of N for plant use (Rice et al., 1987; McCarthy et al., 1995; Halvorson et al., 2001; Sainju and Singh, 2001; Dinnes et al., 2002). In contrast, no-tillage system cause minimal soil disturbance and increase the buildup of surface residue, which may increase both N immobilization (Gilliam and Hoyt, 1987) and N losses by leaching (Tyler and Thomas, 1977) and denitrification (Gilliam and Hoyt, 1987). Tillage greatly affects soil moisture and temperature, which in turn affect soil N dynamics (Torbet and Woods, 1992; Nadelhoffer et al., 1991). The use of conservation tillage has been reported to increase short-term immobilization due to the slower plant decomposition process when tillage is limited (Gilliam and Hoyt, 1987; Wood and Edwards, 1992). Generally, in conservation tillage, fertilizer N rates have been increased as much as 25% to prevent yield limitations from short term immobilization (Randall and Bandel, 1991). It has been hypothesized that application efficiency of fertilizer N can be enhanced by synchronizing fertilizer application with plant uptake needs (Keeny, 1982). Fertilizer applied during peak plant N demand can limit fertilizer N immobilization and/or losses from the soil-plant system due to leaching and denitrification and to increase N use efficiency (Olson and Kurtz, 1982; Keeny, 1982). The sustainability of any crop production system depends on maintaining adequate soil nutrients such as nitrogen. Similarly, a beneficial tillage system for the soil with the integration of applied N fertilizer dynamics is needed. Therefore, the present study was planned to 1) determine the impact of tillage system on nitrogen application rates and 2) to examine the impact of nitrogen application timing within these tillage systems on maize production. MATERIALS AND METHODS In order to study the effect of different nitrogen levels (N) and its application at various growth stages (S) under no tillage (NT) and conventional tillage (CT) on maize yield, experiments were conducted at Cereal Crops Research Institute, Pirsabak, Nowshera for two consecutive years (2004-2005). The experimental site has a latitude of 34o N, longitude 72o E and altitude of 288 m above sea level. Average temperature and total rainfall during the cropping season 2004 and 2005 are shown in Table 1 for each month. The soil of Research Institute is sandy loam, moderately calcareous, having 0.034% nitrogen (Bremmer and Mulvaney, 1982), 0.0029% phosphorus (Soltanpour and Schawab 1978), 0.051% potash (Richard, 1954), 0.028% total soluble salts (Richard, 1954) and 0.34% organic matter (Nelson and Sommer, 1982) with a pH of 7.7 (Mclean 1982). The experiments were conducted in Randomized Complete Block (RCB) design in a split plot arrangement having four replications. Experiment consisted of two tillage systems (NT and CT), three levels of N fertilizer (60,120 and 180 kg N ha-1) and N application at six growth stages of crop (Full dose at sowing (S1), full dose at knee high stage of the plant (S2), three equal splits of the dose i.e. (at sowing + knee high + pre tasselling stage) (S3), two equal splits of the dose i.e. (at sowing + knee high stage) (S4), two equal splits of the dose i.e. (at sowing + pre tasselling stage) (S5) and two equal splits of the dose i.e. (at knee high + pre tasselling stage)( S6). The combinations of tillage systems and N levels were allotted to main plots while application stages to sub plots. Each sub plot was 5 m long and 4.5 m wide having 6 rows of 75 cm apart with plant to plant distance of 25 cm. Conventional tillage (CT) was practiced according to the prevailing farmers’ practices. No preparatory or post sowing tillage was carried out in no-till (NT) system. Planting was done by dibbling method in both the tillage systems. Maize variety Azam was planted on 17 and 19th June in 2004 and 2005, respectively. Details and combination of the treatments were as follow: FACTOR - C:

N Application at Various Growth Stages (S)

A seed rate of 30 kg ha-1 was used for both tillage systems. The seed was treated with confidor powder @ 7g kg before sowing to control the insects attack in the earlier stages of crop growth. Two seeds per hill were planted in each sub-plot. The seasonal and perennial weeds were controlled by spraying round-up herbicides @ 2.47 L ha-1 two weeks before sowing. After sowing, the whole experimental area was sprayed with Primextra gold @ 2 L ha-1 for the control of seasonal weeds. The recommended dose of phosphatic fertilizer i.e. 30 kg P2O5 ha-1 was applied before planting during land preparation. The N application at various growth stages was applied by side dressing method. A total of 6-8 irrigations were practiced during the crop period in both years. Granular insecticides (Furadon 10%) were applied twice @ 20 kg ha-1 to control stem borer. Thinning was done after complete emergence to adjust to one plant per hill. -1

159


Table I

Average air temperature and rainfall at CCRI Pirsabak, Nowshera for crop growing season 2004 & 2005

Month July August September October November Total rainfall during growing season Without parenthesis With parenthesis

Max T (Co) 38.13 (36.19) 36.30 (34.93) 35.87 (34.83) 28.00 (23.74) 26.83 (27.63) = 176.73 (344.50) = for crop season 2004. = for crop season 2005.

Min T (Co) 26.55 (26.03) 25.19 (23.65) 22.60 (22.36) 14.74 (15.06) 9.03 (7.03)

Total Rainfall (mm) 21.14 (243.50) 5.66 (94.15) 24.00 (7.50) 106.18 (0) 19.75 (0)

Statistical Analysis The data recorded were analyzed statistically combined over years using analysis of variance techniques appropriate for randomized complete block design. Main and interaction effects were compared using LSD test at 0.05 level of probability, when the F-values were significant (Steel and Torrie, 1980). RESULTS AND DISCUSSION Grains Ear-1 Data regarding grains ear-1 are given in Table II. Statistical analysis showed that the effects of T, N and S were significant for grains per ear. All interactions were also significant for grain ear-1. More grains ear-1 was observed in CT as compared to NT system. The number of grains ear-1 remained at par when N level was increased from 60 to 120 kg N ha-1 but further increase in N level to 180 kg N ha-1 resulted in significant increase in grains ear-1. Nitrogen application at various growth stages was significant for grain ear-1. Number of grains increased when N was applied as split compared to the full (sole) application at sowing or knee high stage. The mean comparisons within split application had also variation for number of grains ear-1. Number of grains seems to be enhanced when N was applied in two splits as compared with three splits. Within two splits application, it seems that late N availability is crucial in combination with early or mid application in terms of increased grain formation. The interaction among tillage practices and nitrogen levels reflected that even low dose of N (60 kg N ha-1) can be effectively utilized under CT in terms of grain formation. While, NT increased number of grains ear-1 only at higher dose of N. The interaction between T and S indicated that number of grains increased when N fertilizer applied as sole at sowing and in two equally splits, i.e. at sowing and pre tasselling under NT practice. In case of CT system, the number of grains seems more responsive to split N application. The interaction of N and S revealed that number of grains increased with split N application than sole at sowing or knee high stage with at each level of N fertilizer. The interaction of all factors i.e. tillage practices, nitrogen levels and its stages of application indicated that in NT system, delay or split application produced more grains with 60 kg N ha-1, while 120 and 180 kg N ha-1 had more number of grains with sole application at sowing and with two splits i.e. at sowing and pre tasselling. In case of CT system, late or split application gave better results in respect of number of grains per ear with every level of application. Most of the researchers attributed increase in grain yield and other related factors like grains per ear in CT system to tillage operations and soil disturbance which generally can cause an increase in soil aeration, residue decomposition, organic N mineralization and the availability of N for plant use (Rice et al., 1987; McCarthy et al., 1995; Halvorson et al., 2005; Sainju and Singh, 2001; Dinnes et al., 2002). Likewise, Monneveux et al. (2006) reported less number of grains per ear in maize in zero tillage as compared to CT. Increase in yield and yield related components in response to N rates have also been reported by many researchers. Maqsood et al., (2001) found higher number of grains per ear at 120 and 100 kg NP ha-1 and concluded that high levels of N and P probably increased the size of individual ears and thus number of grains per ear. Costa et al. (2002) reported that ear length and ear diameter increased when N level was increased from 0 to 85 kg ha-1 and did not find any effect above this rate. They also observed that ear diameter was generally larger at 85 and 170 kg N ha-1 than the highest N fertilization rates.


160

Grains ear-1 as affected by three levels of N applied to NT and CT systems and its application at various growth stages averaged over two years N (kg ha-1) Tillage Stages Mean 60 120 180 NT S1 369.58 410.71 449.67 409.99 S2 337.29 436.38 384.17 385.94 S3 349.42 399.29 416.13 388.28 S4 370.75 339.33 412.67 374.25 S5 364.83 440.13 452.63 419.19 S6 415.79 360.88 432.38 403.01 CT S1 487.75 417.46 431.71 445.64 S2 479.04 441.29 478.63 466.32 S3 470.25 459.42 472.29 467.32 S4 499.33 455.29 465.75 473.46 S5 546.38 445.46 470.33 487.39 S6 502.75 456.67 497.25 485.56 TxN NT 367.94 397.78 424.60 396.78 Ct 497.58 445.93 469.33 470.95 SxN S1 428.67 414.08 440.69 427.81 S2 408.17 438.83 431.40 426.13 S3 409.83 429.35 444.21 427.80 S4 435.04 397.31 439.21 423.85 S5 455.60 442.79 461.48 453.29 S6 459.27 408.77 464.81 444.28 Mean 432.76 421.86 446.97 Means comparison for stages of N application with statistical significance Contrast 1st mean 2nd mean Sign. Full vs. Split 426.97 437.31 ** Full early vs. Full mid 427.81 426.13 ns 3 Split vs. 2 Split 427.80 440.48 * Early+mid vs.(Early+late)+(Mid+late) 423.85 448.79 ** Early+late vs. Mid+late 453.29 444.28 ns Year 1 vs. Year 2 454.29 413.43 ** Tillage = ** Nitrogen= ** Stages= ** TxN= ** TxS = ** NxS = ** TxNxS= ** S1 = Full dose at sowing S2 = Full dose at knee high stage S3 = Three splits of the dose (at sowing, knee high, pre tasselling) S4 = Two splits of the dose (at sowing, knee high) S5 = Two splits of the dose (at sowing, pre tasselling) S6 = Two splits of the dose (at knee high, pre tasselling) Table II

Thousand Grain Weight Data regarding thousand grain weights are shown in Table III. Statistical analyses of the data showed T and S significantly affected grain weight of maize. The effect of N on grain weight was not significant. The interactions among TxN, TxS, NxS, TxNxS were also significant for grain weight. Grain weights were significantly different in both years of the experiment. Heavier grains were obtained during first year (2004) than second year (2005). Conventional tillage produced heavier grains than no tillage. Nitrogen application at various growth stages had significant influence on grain weight. Grain weight enhanced when N was applied in splits as compared to full application at sowing or knee height. However, full application at sowing proved superior in terms of thousand grain weight than applied at knee high stage. Similarly three split application of N recorded higher thousand grain weight than two splits. CT produced heavier grains as compared to NT system. The TxN interaction indicated that heavier grains were obtained in CT than NT at all levels of N fertilizer. The TxS interaction showed that thousand grain weights were obtained increased under CT than NT system irrespective of N application stages. The highest thousand grain weight were obtained with three equally splits doses followed by full dose application at sowing while the lowest were recorded with full application at knee high stage under CT practice. The highest thousand grain weight was obtained with two split applications i.e. at knee high and pre-tasselling while lowest was observed with sole application at sowing


161

under NT system. The interaction between N and S revealed that highest thousand grain weights was either obtained with 60 or 180 kg N ha-1 under split application. While the performance of N as sole application at sowing improved with increasing in N levels. In contrast to that, sole N applied at knee high stage produced heavier grains at 60 and 120 kg N ha-1 than 180 kg N ha-1. The interaction among T, N and S exhibited that highest thousand grain weight was obtained under CT with 180 and 60 kg N ha-1as sole dose at sowing and with three splits, respectively. The lowest thousand grain weight was observed under NT at 60 kg N ha-1 as sole application at sowing. Similarly year had also significant interaction with tillage, N levels and its application at various stages for grain weight. Grain weights were significantly different in both years of the experiment. Heavier grains were obtained during first year (2004) than second year (2005). As it is evident from the rainfall data (Table I) that first year of the experiment was more favorable for high corn production and thus produces heavier grains than second year. A wet season in 2005 resulted in runoff which might created N deficiency and resulted in yield difference. For application of N, the general conclusion among researchers has been that N should be applied close to the time when needed by the crop i.e. side-dressed several weeks after corn emergence for getting higher yield and yield related components (Aldrich, 1984; Fox et al., 1986). Thiraporn et al., (1983) have reported strong positive relationship of kernel weight with final yield components in maize. Maqsood et al. (2001) reported that high levels of N markedly increased thousand grain weight of maize. Similar results were also obtained by Akain et al. (1993) and Samad (1994) who concluded that increasing levels of N (up to 112 kg ha-1) increased thousand grain weights. The major contributor to maintaining crop yield with reduced rates of N fertilizer has been attributed to the increase recovery of N by the corn plant when N is split applied (Herron et al., 1971; Grewing et al., 1979; Bundy et al., 1994; Guillard et al. and Gehl et al., 2005). This increased efficiency of split N applications probably result from the application of N just before the period of rapid N uptake by corn and a shorter exposure time to losses by leaching or de-nitrification (Bundy et al., 1994). However, Reeves and Touchton, (1986) reported that applying N at planting resulted in the best early season growth than delayed application until 5 weeks after planting, thus resulted heavier grains with full application of N fertilizer at sowing. Crop growth rate during flowering and grain filling increased with increase in N rates, resulting in higher kernel number per square meter and grain weight (Rozas et al., 1999). Grain Yield (Mg ha-1) Data regarding grain yield of maize are presented in Table IV. Analysis of the data revealed that tillage (T) and fertilizer nitrogen (N) significantly affected grain yield of maize. The stages of N application (S) did not show any implication on grain yield. However, planned mean comparison detected that split application of N resulted in higher grain yield as compared to full dose of N at sowing or knee height. The interaction among T x N, N x S and T x N x S were also significant for grain yield. Year as a source of variation also had significant effect on grain yield of maize. Conventional tillage (CT) produced significantly higher grain yield as compared to no-tillage (NT). Grain yield increased with increase in N level from 60 kg ha-1 to 120 kg ha-1 but further increase in N level to 180 kg ha-1 declined grain yield of maize. Mean values of T x N interaction indicated that grain yield had a positive linear relationship with increasing levels of N in CT system while grain yield enhanced with increase in N level from 60 to 120 kg N ha-1, but further increase in N to 180 kg ha-1 decreased grain yield of maize in NT system. The N x S interaction showed that grain yield mostly increased with increase in N level irrespective of N application stages. The interaction of all the three factors i.e. tillage practices, nitrogen level and fertilizer application stages indicated that the highest grain yield was produced by 180 kg N ha-1 when applied in three splits under CT while NT was beneficial for grain yield when 120 kg N-1was applied in two split doses. Weather conditions varied and high rainfall occurred during 2005 as compared to 2004 (Table I). These variations resulted in wide differences in corn grain yield and other growth and yield related parameters. High corn production in 2004 might be due to frequent and uniform distribution of rainfall while low corn production in 2005 were attributed to the excess of rainfall during the growing season which causes runoff and leaching of N and ultimately N deficiency. The lower grain yield with NT probably resulted from the slow early crop growth compared with the CT system (Halvorson et al., 2006; Bermudez and Mallarino, 2004). Sims et al., (1998) suggested that pre-plant tillage may be necessary to optimize grain yield and reported lower continuous corn yields with NT compared with CT. However, many researchers suggested that the delay in the early crop growth and development with NT had no detrimental effect on final crop yield (Mehdi et al., 1999; Wolf and Eckert, 1999). Similarly, Beyaert et al., 2002 reported that the effects of different tillage systems on early corn growth did not result in biological consequences sufficient to affect reproductive yield. Modifying the NT system by adopting zero tillage (ZT) system did not


162

improve the growing conditions sufficiently for corn to produce significantly higher yields, nor did it cause a serious reduction in yield relative to CT. In spite of the yield differences, no-till remains an extremely important tool to reduce soil erosion on the highly erodible, sloping silt-loam soils (Howard, 2000). Thomas et al. (1973) and Kitur et al. (1984) argued that lower grain yield of maize might be due to greater N immobilization and NO3 leaching in NT as compared to CT. Jones et al. (1969) noted increase soil water in the root zone as the primary factor causing plant growth and yield increase with CT. Improved grain yield in CT system has also been reported by many researchers (Halvorson et al., 2006; Vyn and Raimbault, 1992; Howard, 2000; Wilhelm and Wortmann, 2004; Vetsch and Randall, 2002; Vetsch and Randall, 2004; Sims et al., 1998; Halvorson et al., 2006; Dick et al., (1986) and Alkaisi and Licht, (2004). Similarly, Pederson and Lauer, (2003) noted 5% lower corn yield while Erbach et al. (1992); Hussain et al. (1999); Vyn and Raimbault, (1992) reported 35% lower grain yield in NT than CT. The optimum N rate (needed to achieve maximum yield) is influenced by factors including soil type, tillage, irrigation, fertilizer timing and method, and crop yield potential. These factors, as well as the interaction of these factors, will vary greatly from one location to another in a given geographic region (Gehl et al., 2005). Results indicate that yield potential is more strongly influenced by previous crop, fertilizer N rate, and N placement method than tillage system (Kelley and Sweeney, 2005). Maize begins to rapidly taken up N during the middle vegetative growth period with the higher rate of N uptake occurring near silk (Hanway, 1963). Time of N application studies have been reported extensively in the literature. The general conclusions among researchers are that N application should be synchronized with the crop demand i.e., side-dressed several weeks after corn emergence (Aldrich, 1984; Fox et al., 1986). Plant uptake of fertilizer N is more efficient when applied just before maximum plant need, subject to lower N losses through denitrification or leaching, or lower N immobilization in organic forms (Bigiriego et al., 1979; Wells and Bitzer, 1984). When fertilizer was applied at six leaf stage to the maize, N uptake and grain yield were increased compared with fertilization at planting (Rozas et al., 1999). Higher N uptake and grain yield with fertilization at six leaf stage have been reported by other researchers (Wells and Bitzer, 1984; Fox et al., 1986; Wells et al., 1992). Likewise, Lathwell et al. (1970) have shown increased grain yields and more efficient use of fertilizer N by corn when N application was delayed until several weeks post emergence rather than applied before planting. Fertilizer N was utilized more effectively, resulting in increased yields when applied 5 weeks after planting rather than at planting (Reeves and Touchton, 1986). These results agree with those of Jung et al. (1972) and Russelle et al. (1983), who reported increased effectiveness of N from delayed applications. Improved efficiency with delayed N application is consistent with the concept of providing N at the time of maximum uptake, which occurs in a two to three weeks period just before silking (Jordan et al., 1950; Russelle et al., 1983) or slightly earlier (Hanway, 1962). This increased efficiency is the result of a combination of plant and soil factors. Grain yield increases with increasing level of N (Torbet et al., (2001) and Ma et al., 2005; Schmidt et al., 2002). Gehl et al. (2005) achieved maximum grain yield with 185 kg N ha-1 at all sites but reported that in most instances 125 kg N ha-1 was sufficient to achieve maximum grain yield. A possible means to increase the fertilizer N efficiency is to split-apply the fertilizer N. The side dress application, N fertilization several weeks after corn emergence, has maximized the efficiency of fertilizer N in most situations (Piekielek and Fox, 1992; Fox et al., 1986; Aldrich, 1984; Olson and Kurtz, 1982). Also, the presence of plants at the time of side dressing application reduces NH3 volatilization loss by shading and absorption of some of the evolved NH3 (Harper et al., 1983). Split application of N results in greater N efficiency and recovery by the corn plants (Herron et al., 1971; Gerwing et al., 1979; Bundy et al., 1994; Guillard et al., 1999).

163


Likewise, Bundy et al. (1994) noted greater N efficiency when applied just before the period of rapid N uptake by corn and a shorter exposure time to leaching and de-nitrification. Similarly, Rozas et al. (2001) reported that N application at later stage is better than at sowing because of denitrification: When N was applied at planting, cumulative de-nitrification losses were greater than those observed for fertilization at the six leaf stage. However, Jokela and Randall, 1989 reported that delaying N application from planting to 8 leaf stage did not increase grain or total DM production or fertilizer N use efficiency. Table III

Grain weight (g) as affected by three levels of N applied to NT and CT systems and its application at various growth stages averaged over two years

N (kg ha-1) Tillage Stages 60 120 NT S1 241.50 291.88 S2 258.50 259.50 S3 278.13 293.75 S4 260.00 260.00 S5 289.00 292.63 S6 308.63 298.13 CT S1 311.13 331.13 S2 305.00 313.25 S3 355.50 328.13 S4 347.88 304.50 S5 304.25 326.13 S6 329.63 296.25 TxN NT 272.63 282.65 Ct 325.56 316.56 SxN S1 276.31 311.50 S2 281.75 286.38 S3 316.81 310.94 S4 303.94 282.25 S5 296.63 309.38 S6 319.13 297.19 Mean 299.09 299.60 Means comparison for stages of N application with statistical significance Contrast 1st mean Full vs. Split 291.25 Full early vs. Full mid 300.06 3 Split vs. 2 Split 313.85 Early+mid vs.(Early+late)+(Mid+late) 296.40 Early+late vs. Mid+late 282.60 Year 1 vs. Year 2 308.58 Tillage= ** Nitrogen= ns Stages= ** TxN= ** TxS = ** NxS = ** TxNxS= ** S1 = Full dose at sowing S2 = Full dose at knee high stage S3 = Three splits of the dose (at sowing, knee high, pre tasselling) S4 = Two splits of the dose (at sowing, knee high) S5 = Two splits of the dose (at sowing, pre tasselling) S6 = Two splits of the dose (at knee high, pre tasselling).

180 261.38 282.88 301.63 289.00 310.25 310.63 363.38 275.50 326.00 317.00 301.88 326.63

Mean 264.92 266.96 291.17 269.67 297.29 305.79 335.21 297.92 336.54 323.13 310.75 317.50

292.63 318.40

282.63 320.17

312.38 279.19 313.81 303.00 306.06 318.63 305.51

300.06 282.44 313.85 296.40 304.02 311.65

2nd mean 301.13 282.44 296.88 297.13 311.65 294.22

Sign. ** ** ** ** * **


Table IV

164

Grain yield (Mg ha-1) as affected by three levels of N applied to NT and CT systems and its application at various growth stages averaged over two years

N (kg ha-1) Tillage Stages 60 120 NT S1 4.57 6.10 S2 5.08 6.56 S3 5.16 6.11 S4 4.88 6.69 S5 5.43 6.49 S6 5.93 6.77 CT S1 6.47 7.06 S2 6.57 6.75 S3 6.44 7.05 S4 7.06 7.02 S5 6.68 7.13 S6 7.00 6.90 TxN NT 5.17 6.45 CT 6.70 6.99 SxN S1 5.52 6.58 S2 5.83 6.65 S3 5.80 6.58 S4 5.97 6.86 S5 6.06 6.81 S6 6.46 6.84 Mean 5.94 6.72 Planned means comparison for stages of N application with statistical significance Contrast 1st mean Full vs. Split 6.26 Full early vs. Full mid 6.33 3 Split vs. 2 Split 6.41 Early+mid vs.(Early+late)+(Mid+late) 6.48 Early+late vs. Mid+late 7.02 Year 1 vs. Year 2 7.41 Tillage = ** Nitrogen= ** Stages= ns TxN= ** TxS = ns NxS = ** TxNxS= * S1 = Full dose at sowing S2 = Full dose at knee high stage S3 = Three splits of the dose (at sowing, knee high, pre tasselling) S4 = Two splits of the dose (at sowing, knee high) S5 = Two splits of the dose (at sowing, pre tasselling) S6 = Two splits of the dose (at knee high, pre tasselling).

180 6.70 5.39 6.11 6.02 6.00 6.37 7.12 6.77 7.56 7.21 7.04 6.96

Mean 5.79 5.67 5.79 5.86 5.97 6.36 6.88 6.70 7.02 7.10 6.95 6.95

6.10 7.11

5.91 6.93

6.91 6.08 6.83 6.61 6.52 6.67 6.60

6.33 6.19 6.41 6.48 6.46 6.66

2nd mean 6.64 6.19 6.72 6.84 6.66 5.43

Sign. ** ns ns ns ns **

CONCLUSION Conventional tillage proved superior in term of grains ear-1, grain weight and grain yield as compared to No-tillage. Yield and yield components significantly improved up to 120 kg N ha-1 however, additional N up to 180 kg ha-1 failed to induce any increase. Split application significantly increased grains ear-1, grain weight and grain yield as compared to sole application. REFERENCES Aldrich, S. 1984. Nitrogen management to minimize adverse effect on the environment. P. 663-673. in R.D. Hauck (ed.) Nitrogen in crop production. ASA, Madison, WI. Alkain, A., B. Sade, A. Tamkoe and A. Topat, 1993. Effect of different plant densities and nitrogen fertilizer rates on grain yield and some morphological characters of maize. Doga turk Tarim Ve Ormoncilik Dergisi. 17: 281-294. Al-Kaisi, M. and M.A. Licht, 2004. Effect of strip tillage on corn nitrogen uptake and residual nitrate accumulation compared with no-tillage and chisel plow. Agron. J. 96:1164-1171. Beyaert, R.P., J.W. Schott and P.H. White. 2002. Tillage effects on corn production in a coarse-textured soil in suthern Ontario. Agron.J.94: 767-774.


165

Bigeriego, M., R.D. Hauck, and R.A. Olson. 1979. Uptake, translocation and utilization of N–depleted fertilizer in irrigated corn. Soil Sci. Soc. Amer. J. 43:528-533. Bremner, J.M. and C.S. Mulvaney. 1982. Nitrogen-Total. In: Methods of soil analysis, Part 2, Chemical and Microbiological Properties, (eds A.L. Page, R.H. Miller & D.R. Keeney), pp. 595-624. Amer. Soc. of Agron. Madison, Wisconsin. Costa, C., L.M. Dwyer, D.W. Stewart, and D.L. Smith. 2002. Nitrogen effect on grain yield and yield components of leafy and nonleafy maize genotypes. Crop Sci. 42; 1556-1563 Dick, W.A., D.M. Van Doren, G.B. Triplett, and J.E. Henry. 1986. Influence of long-term tillage and rotation combinations on crop yields and selected soil parameters: 1. Results obtained for a Mollic Ochraqualf soil. Res. Bullet. 1180. Ohio Agric. Res. and Dev. Centre, Ohio State Univ., Wooster. Dinnes, D.L., D.L. Karlen, D.B. Jaynes, T.C. Kaspar, J.L. Hatifield, T.S. Colven and C.A. Cambardella. 2002. Nitrogen management strategies to reduce nitrate leaching in tile-drained Midwestern soils. Agron. J. 94:153-171. Erbach, D.C., J.G. Benjamin, R.M. Cruse, M.A. Elamin, S. Mukhtur and C.H. Choi. 1992. Soil and corn response to tillage with para-plow. Trans. ASAE. 35, 1347-1354. Fox, R.H., J.M. Kern and W.P. Piekieleck. 1986. Nitrogen fertilizer source, and method and time of application effects on no-tillage corn yield and nitrogen uptake. Agron .J.78: 741-746. Gangwar, K.S., K.K. Singh, S.K. Sharma and O.K. Tomar. 2006. Alternative tillage and crop residue management in wheat after rice in sandy loam soils of Indo-Gangetic plains. Soil & Tillage Res. 88:242-252. Gehl, R.J., J.P. Schmidt., L.D. Maddux and W.B.Gordon. 2005. Corn yield response to nitrogen rate and timing in sandy irrigated soils. Agron. J. 97:1230-1238 Gerwing, J.R., A.C. Caldwell and L.L. Goodroad. 1979. Fertilizer nitrogen distribution under irrigation between soil, plant and aquifer. J. Envir. Qual. 8: 281-284. Gilliam and G.D. Hoyt. 1987. Effect of conservation tillage on fate and transport of nitrogen. P.217-240. In T.J. Logan et al. (ed.). Guillard, K., T.F. Morris and K.L. Kopp. 1999. The pre side-dress soil nitrate test and nitrate leaching form corn. J. Envir. Qual. 28: 1845-1851. Halvorson, A.D., A.R. Mosier., C.A. Reule and W.C. Bousch. 2006. Nitrogen and tillage effects on irrigated continuous corns. Agron. J. 98:63-71. Halvorson, A.D., B.J. Weinhold and A.L. Black .2001. Tillage and nitrogen fertilization influences on grain and soil nitrogen in a spring wheat –fallow system. Agron. J. 93: 1130-1135. Halvorson, A.D., F.C. Schweissing, M.E. Bartula and C.A. Reule. 2005. Corn response to nitrogen fertilization in a soil with high residual nitrogen. Agron. J. 97: 1222-1229. Hanway, J.J. 1963. Growth stages of corn (Zea mays L.). Agron. J. 55:487-492. Hanway. J.J. 1962. Corn growth and composition in relation to soil fertility: II. Uptake of N, P. and K and their distribution in different plants parts during the growing season. Agron. J. 54:217-222. Harper, L.A., V.R. Catchpoole, R. Davis and K.L. Wier. 1983. Ammonia volatilization: Soil, plant, and micro-climate effects on diurnal and seasonal fluctuations. Agron. J. 73: 104-107. Herron, G.M., A.F. Dreier, A.D. Flowerday, W.L. Colvine and R.A. Olson. 1971. Residual mineral N accumulation in soil and its utilization by irrigated corn. Agron. J. 63: 322-327. Howard, D. D. and M.E. Essington. 1998. Effects of surface-applied limestone on the efficiency of urea-containing nitrogen sources for no-till corn. Agron. J. 90: 523-528. Hussain, I., K.R. Olson and S.A. Ebelhar. 1999. Impact of tillage and no-till on production of maize and soybean on eroded Illinois silt loam soil. Soil Tillage Res. 52: 37-49. Ihsan, H., I.H. Khalil, H. Rahman and M. Iqbal. 2005. Genotypic variability for morphological and reproductive traits among exotic maize hybrids. Sarhad J. Agric.21 (4): 599-602. Jokela, W.E. and G.W. Randall. 1989. Corn yield and residual soil nitrate as affected by time and rate of nitrogen application. Agron. J. 81:720-726. Jones, J. N., J.E. Moody and J.H. Lillard. 1969. Effects of tillage, no-tillage and mulch on soil water and pant growth. Agron. J. 61: 719-721. Jordan, H.V., K.D. Liard and D.D. Ferguson. 1950. Growth rates and nutrient uptake by corn in a fertilizer-spacing experiment. Agron. J. 42:261-268. Jung, Jr., I.A. Perterson and I.E. Schrader. 1972. Response of irrigated corn to time, rate and source of applied N on sand soils. Agron. J. 64: 668-670. Keeney, D.R. 1982. Nitrogen indices. pp.711-733. In A.L. Page, R.H. Miller and D.R. Keeney (eds.) Methods of soil analysis. Part-2, ASA, CSSA, SSSA, Madison. Kelley, K.W. and D.W. Sweeney. 2005. Tillage and urea ammonium nitrate fertilizer rate and placement affects winter wheat following grain sorghum and soybean. Agron. J. 97: 690-697. Khan, K., F. Karim, M. Iqbal, H. Sher and B. Ahmad. 2004. Response of maize varieties to environments in two agroecological zones of NWFP: Effects on morphological traits. Sarhad J. Agric. 20 (3): 395-399.


166

Khan, K., M. Iqbal, Z. Shah, B. Ahmad, A. Azim and H. Sher. 2003. Grain and stover yield of corn with varying times of plant density reduction. Pak. J. Biol. Sci. 6(19): 1614-1743. Kitur, B.K.., M.S. Smith, R.L. Blovins, and W.W. Frye. 1984. Fate of N-depleted ammonium nitrate applied to no-tillage and conservation tillage maize. Agron. J. 76:240-242. Lathwell, D.J., D.R. Bouldin, and W.S. Reid. 1970. Effect of nitrogen fertilizer application in agriculture. P. 192-206. in Relationship of agriculture to soil and water pollution. Proc. Cornell Univ. Conf. on Agric. Wast Mgt., Syrecuse, NY. 19-21 Jan. 1970. Cornell Univ., Ithaca, NY. Ma, B.L., K.D. Subedi and C. Costa. 2005. Comparison of crop-based indicators with soil nitrate test for corn nitrogen requirement. Agron. J. 97: 462-471. Maqsood, M., A.A. Amanat, I. Iqbal and M.I. Hussain. 2001. Effect of variable rates of nitrogen and phosphorus on growth and yield of maize (Golden). Biol. Sci. 1 (1): 19-20. McCarthy, G.W., J.J. Meisinger and F.M.M. Jenniskens. 1995. Relationship between total-N, biomass-N and active-N under different tillage systems and N fertilizer treatments. Soil Biol. Biochem. 27:1245-1250. Mehdi, B.B., C.A. Madramootoo and G.R. Mehuys.1999. Yield and nitrogen content of corn under different tillage practices. Agron. J. 91:631-636. MINFAL. 2005-06. Agric. Statistics of Pakistan. Ministry of Food, Agric. & Livest. Islamabad. Monneveux, E. Quillerou, C. Sanchez and J. Lopez-Cesati. 2006. Effect of zero tillage and residue conservation on continuous maize cropping in a subtropical environment (Mexico). Plant & Soil. 279:95-105. Nadolhffer, K.J., A.E. Gibblim, G.R. Shaver, and J.A. Laundre. 1991. Effect of temperature and substrate quality on element mineralization, in six arctic soils. Ecol. 72:242-253. Nelson, D.W. and L.E. Sommers. 1982. Total carbon, organic carbon and organic matter, In: Methods of soil analysis, Part 2, Chemical and Microbiological Properties, (eds A.L. page, R.H. Miller & D.R. Keeney), pp. 547-577. Amer. Soc. of Agron. Madison, Wisconsin. Olson, R.A and L.T. Kurtz. 1982. Crop nitrogen requirement, utilization, and fertilization. P.567-599. In F.J. Stevenson et al. (ed.) Nitrogen in agriculture soils, Agron. Managr .22. ASA and SSSA Madison, WI Pederson, P. and J.G. Lauer .2003. Corn and soybean response to rotation sequence, row spacing, and tillage system. Agron. J. 95:965-971. Piekielek, W.L. and R.H. Fox. 1992. Use of chlorophyll meter to predict side-dress nitrogen requirements for maize. Agron. J. 84:59=65. Randall, G.W. and V.A. Bandel. 1991. Overview of Nitrogen management for conservation tillage systems: P. 39-63 in T.J. Logan et al. (ed.) Effects of conservation tillage on groundwater quality, nitrogen and pesticides. Lewis Publ., Chelsea, MI. Reeves, D.W and J.T. Touchton. 1986. Sub soiling for nitrogen applications to corn grown in a conservation tillage system. Agron . J. 78: 921-926. Rice, C.W., J.H. Grove and M.S. Smith. 1987. Estimating soil net nitrogen mineralization as affected by tillage and soil drainage due to topographic position. Canad. J. Soil Sci. 67:513-520. Richard, L.A. 1954. Diagnosis of saline and alkali soil. USDA Hand book 60, USA. Russelle, M.P. and R.A.Olson. 1983. Nitrogen accumulation rate of irrigated maize. Agron . J. 75:593-598. Saeed, M.T. and M. Saleem. 2000. Estimate of gene effects for some important qualitative plant traits in maize dialeal crosses J. Biol. Sci. 3(7): 1138-1140. Sain Rozas, H.R., H.E.Echeverrria and L.I. Picone. 2001. Denitrification in maize under no-tillage: effect of nitrogen rate and application time .Soil Sci. Soc. Amer. J. 65: 1314-1323. Sain Rozas.H., H.E. Echeverria., G.A.Studdert and F.H. 1999. No-tillage maize nitrogen uptake and yield: Effect of urease inhibitor and application time. Agron. J. 91:950-955. Sainju, U.M. and B.P. Singh. 2001. Tillage, cover crop, and kill-planting date effects, on corn yield and soil nitrogen. Agron. J. 93: 878-868. Samad, A. 1994. Effect of different combinations of NPK on the grain yield and yield component of maize varieties. Sarhad J. Agric. 8: 17-21. Schmidt, J.P., A.J. Dwjoia., R.B. Ferguson., R.K. Taylor., R.K. Young and J.L. Halvin 2002. Corn yield response to nitrogen at multiple in field locations. Agron. J. 94:798-806. Simes, Al. L., J. S. Schepers,. R.A Olson, and J. F. Power. 1998. Irrigated corn yield and nitrogen accumulation response in a comparison of no-till and conventional till: Tillage and surface-residue variables. Agron. J. 90: 630-637. Soltanpour, P.N. and A.P. Schwab. 1978. A new soil test for simultaneous extraction of macro and micro nutrients in alkaline soil common. Soil. Sci. Plant Anal. 8: 195-207. Steel, R.G.D. and J.H. Torrie. 1980. Principles and procedures of statistics: A biometrical approach. 2nd ed. McGraw-Hill, New York. Thiraporn, R., G. Geisler and P. Stamp. 1983. Yield and relationship among yield components and N and P-related traits in maize genotypes under tropical conditions. J. Agron. & Crop Sci. 152: 460-468.


167

Thomas, G.W., R.L. Blevins, R.E. Philips and M.A. McMahon. 1973. Effect of killed sod mulch on nitrate movement and corn yield. Agron. J. 65:736-739. Torbert, H.A., K.N. Potter and J.E. Morrison, Jr. 2001. Tillage system, fertilizer nitrogen rate and timing effect on corn yield in the taxes black land prairie. Agron. J. 93: 1119-1124. Torbet, H.A., and C.W. Wood. 1992. Effects of soil compaction and water -filled pore space on soil microbial activity and N losses. Commun. Soil Sci. Plant Anal. 23:1321-1331. Tyler, D.D. and D.W. Thomas. 1977. Lysimeter measurements of nitrate and chloride losses from soil under conventional and no-tillage corn. J. Environ. Qual. 6:63-66. Vetsch, J.A. and G.W. Randall. 2002. Corn production as affected by tillage system and starter fertilizer. Agron. J. 94: 532-540. Vetsch, J.A. and G.W. Randall. 2004. Corn production as affected by nitrogen application timing and tillage. Agron.J.96:502-509. Vyn, T.J. and B.A Raimbault. 1993. Long term effect of five tillage system on corn response and soil structure. Agron. J. 85: 1074-1079. Wells, K.L. and M. J. Bitzer. 1984. Nitrogen management in the no-till system. P. 535-549. In R. D. Hauck et al. (ed.) Nitrogen in crop production. ASA, CSSA, and SSSA, Madison, WI. Wells, K.L., W.O. Thom and H.B. Rice. 1992. Response of no-till corn to nitrogen source, rate, and time of application. J. Prod. Agric. 5: 607-610. Wilhelm, W.W. and C.S. Wortmann. 2004. Tillage and rotation interactions for corn and soybean grain yield as affected by precipitation and air temperature. Agron. J. 96:425-432. Wolfe, A.M. and D. J. Eckert. 1999. Crop sequence and surface reside effects on the performance of no-till corn grown on a poorly drained soil. Agron. J. 91: 363-367. Wood, C.W. and J.H. Edwards. 1992. Agro-ecosystem management effect on soil carbon and nitrogen. Agric. Ecosyst. Envir. 19:123-138.