Keywords: Soil; Penetration resistance; Bulk density; Melon; Tillage.

Transcription

1 Soil Physical Properties and Yield Response of Melon (Colocynthis citrullus L.) to different Tillage Treatments in a Humid Rainforest Soil of Akure, Nigeria Fasinmirin Johnson Toyin Department of Agricultural Engineering, Federal University of Technology, Akure, Nigeria Corresponding author s fasinmirin_johnson@yahoo.com Abstract A field experiment was conducted to investigate the effects of different tillage methods on soil physical properties and yield properties of melon (Colocynthis citrullus L.). Tillage treatments adopted during the study are: No-tillage (NT), one pass of disc plough (Primary Tillage, PT), and ploughing + two passes of disk harrow (Secondary Tillage, ST). The soil of the ST treatment had the highest moisture contents (10.9%) and lowest bulk density (1.15 g cm -3 ), while the soil of the NT treatment had the lowest moisture contents (8.5%) and the highest bulk density (1.55 g cm -3 ) and penetration resistance (300 kpa). Leaf area index values of 0.34, 0.14 and 0.09 were recorded in treatment plots under ST, PT and NT, respectively. Melon root length was highest (34.0 ± 1.85 m) in plots under ST treatment. Melon root length in the ST treatment plots was 78.9 and 161.5% over the root length recorded in PT and NT treatments, respectively. Melon pod yield in the NT treatment plots was ton ha -1. The mean dry of seed yield under NT was 0.60 (±0.07). The mean pod yield in treatment plots under PT and ST are 30.8 and 37.9 tons ha -1, respectively. The mean dry seed yield of melon in the PT and ST treatment plots were 0.44 (±0.10) and 0.47 (±0.04) tons ha -1, which implies about 36.7% and 27.6% reduced yield comparatively with the NT treatment plots, respectively. The difference in the yield recorded from the No-till and primary tillage treatment plots was significant at the 5% probability level. The output of this research is useful to local farmers and agricultural policy makers in decision making as regards appropriate soil tillage that could result to more Melon (Colocynthis citrullus L.) production per hectare of soil. Keywords: Soil; Penetration resistance; Bulk density; Melon; Tillage. 1 Introduction Soil tillage is arguably the most influential manipulation or alteration of soil physical properties because of repetitive application, its depth range extending up to tens of centimeter, and because it influences the type of residue management applied. Likewise, informed tillage application in response to temporal variability in soil hydraulic properties can invoke attractive benefits in areas that have suffered from low yield and inefficient resource allocation in the past (Raper et al., 2000). Soil tillage is among the important factors affecting soil physical properties and crop yield. Among the crop production factors, tillage contributes up to 20% (Khurshid et al., 2006). Tillage method affects the sustainable use of soil resources through its influence on soil properties (Hammel, 1989.), The proper use of tillage can improve soil related constrains, while improper tillage may cause a range of undesirable processes, e.g. destruction of soil structure, accelerated erosion, depletion of organic matter and fertility and disruption in cycles of water, organic carbon and plant nutrient (Lal, 1993). Use of excessive and unnecessary tillage operations is often harmful to soil. Therefore, currently there is a significance interest and emphasis on the shift to the conservation and no-tillage methods for the purpose of controlling erosion process (Iqbal, et al., 2005). Conventional tillage practices modify soil structure by changing its physical 207

2 Nigeria properties such as soil bulk density, soil penetration resistance and soil moisture content. Annual disturbance and pulverizing caused by conventional tillage produce a finer and loose soil structure as compared to conservation and no-tillage method which leaves the soil intact (Rashidi, and Keshavarzpour, 2007). This difference results in a change of number, shape, continuity and size distribution of the pores network, which controls the ability of soil to store and transmit air, water and agricultural chemicals. This in turn controls erosion, runoff and crop performance (Khan et al., 2001). On the other hand, conservation tillage methods often result in decreased pore space (Hill, 1990), increased soil strength (Bauder et al., 1981) and stable aggregates (Home et al., 1992). The pore network in conservational tilled soil is usually more continues because of earthworms, root channels and vertical cracks (Cannel, 1985). Therefore, conservation tillage may reduce disruption of continues pores. Whereas, conventional tillage decreases soil penetration resistance and soil bulk density (Khan et al., 1999). This also improves porosity and water holding capacity of the soil. Continuity of pore network is also interrupted by conventional tillage, which increases the tortuosity of soil. This all leads to a favorable environment for crop growth and nutrient use (Khan et al., 2001). However, the results of notillage are contradictory (Iqbal et al., 2005), No-tillage methods in arid regions of Nigeria had an adverse effect on crop yields (Hemmat and Taki, 2001); while (Chaudhary et al.,1992) comparing conventional tillage method to no-tillage method concluded that higher moisture preservation and 13% more income was obtained in case of no-tillage. At this time, a wide range of tillage methods is being used in Nigeria without evaluating their effects on soil physical properties and crop yield. Therefore, the study was aimed at determining the effect of different tillage methods on soil physical properties and yield of melon in tropical soil of Akure, 2 Materials and Methods 2.1 Location of the Experiment The Research was conducted at the Science and Technology Education Post-Basic project site of the Federal University of Technology, Akure, Nigeria located on latitude 7 o 14ꞌN and longitude 5 o 08ꞌ East. The soil of the study area is a sandy clay soil according to USDA textural classification of soil (Soil Survey Staff, 1999). Akure has a land area of about 2,303 sq km and is situated in the western upland area within the humid region of The area has a general elevation of between meters above mean sea level. Local peaks rise to 1000 m; other hill-like structures which are less prominent rise only a few hundred meters above the general elevations (Fasinmirin and Konyeha, 2009). The pattern of rainfall is bimodal, the first peak occurring in June July, and the second in September, with a little dry spell in August (Fasinmirin, 2007). The mean annual rainfall ranges between 1300 mm to 1500 mm. The soils are light textured, fine sandy loam to fine sandy clay loam. The soil is moderately well supplied organic matter and nutrients. Moisture holding capacity is moderately good. The soil of the environment is however subject to seasonal water logging for varying periods, but generally become dry during the dry seasons which falls within November and March (Fasinmirin and Konyeha, 2009). 2.2 Site Preparation Field experiment was conducted to determine the effect of tillage systems on soil physical properties. The experiment was carried out between the months of March to June Field experiment was conducted in a 2,632.5 m 2 area of the farm. The study site was constantly 208

3 being put to use for the purpose of research on all varieties of arable crops. Paraquat (1,1- dimethyl-4,4-bipyridilium dichloride) was applied using boom sprayer at the rate of 2.5 kg ha -1, for the termination of weeds. Tillage treatments were carried out on the field 10 days after the application of paraquat as follows: plots A (No-till, NT), plot B (Primary tillage, PT) using a tractor mounted disc plough, and plot C (Secondary tillage, ST), which involved ploughing and harrowing operations. The three treatments were replicated three times in a randomized complete block design. The No-till treatment was left under mulch cover from plant residues after herbicide application. The treatments were tested to determine their influence on melon (Egusi) considering soil properties such as bulk density, moisture content, total porosity, macro porosity and micro porosity. 2.3 Agronomic practice and soil measurements After land preparation and field layout, the melon seeds were sown in the split plot design. Each plot was 30 m by 10 m in area, leaving a buffer of one meter between plots. A planting distance of 1m by 1m was maintained in all plots and weeding was done manually at 3 rd, 6 th and 9 th weeks after planting. Soils within 0-10, 10-20, 20 30, and cm depths were sampled at four different locations in each of the treatment plots, 5 m distances apart following a grid sampling pattern. The samples collected from each layer were bulked per plot into one composite sample, thoroughly mixed and air-dried in the laboratory, sieved with a 2-mm sieve and analyzed for soil particles size distribution. The soil moisture content was determined using gravimetric method as described in Fasinmirin and Olorunfemi (2013). Bulk density of soil samples (BD) was determined using the core method described Blake and Hartge (1986) and in D Haene et al. (2008). Total porosity of the soil was assumed 2.65 Mg/m 3 (Suzuki et al., 2004; Fasinmirin and Adesigbin, 2012). Bulk density Total Porosity = 1 (1) Particle density The soil macro and macro porosities were determined following the method described in Fasinmirin and Adesigbin (2012). 2.4 Yield and yield components of plant. Data for the yield response of melon plant such as number of leaves, plant height, and leave area were collected weekly on each of the plot from 1 week after planting (1 WAP) up to 10 weeks after planting (10 WAP). A representative plant was selected in each of the replicates from which leaves area (AOL) were obtained using the Compu eye leaf and symptom area software as described by Bakr (2005). The leaves samples were collected from the no-till, primary and secondary tillage plots weekly. Thereafter, each leaf was captured using a digital camera on a white background at a fix distance and saved into jpg file. The software was also calibrated by capturing a digital image of a conventional ruler using the same settings, which have been used to capture the images of the leaves, i.e. resolution, size ratio, distance between camera and object; afterwards it was also saved as jpg file. The ruler image was opened then the mouse was placed exactly on 0 cm point on the ruler then moved to point 20 cm. To make it more accurate, the covered distance was repeated using same start and end points and then saved. The principal idea of the software is to divide the image into small squares and assess the average colour of every square, where the area of these square units 209

4 Nigeria could be adjusted between 0.1 and 1.0 mm 2. After calibration, the standard-shape image files were opened and analysed by the software, the percentage of leaf area value was calculated for each leaf image. The leaf area was then estimated as follows: LA = 0.75 x L W (2) where: LA, L, W and A are leaf area, leaf length, Leaf maximum width and calibration constant A = 0.75, respectively. The leaf area index was determined from the ratio of the leaf area to the area covered by plant as described by Gong et al. (1995) and Fasinmirin et al. (2009). Plant height (PH) was determined using steel rule. The summary of agronomic measurements conducted during the experiment is shown in Table 1 Fruits from three representative plants in each plot were tagged for ease of identification, harvested separately and put in separate polythene bags. At the end of the harvest, the total weight of harvest in each experimental plot was summed up and divided by the number of tagged plants, which gave the average yield per plant. The average yield per plant per area was converted to yield per hectare (tonha -1 ). At the termination of the project, the plants were uprooted from the plots and the plants yield components were detached i.e. the roots, the stems and the leaves. Plant components were weighed and the values recorded. The yield in each treatment plot was obtained and weighed fresh. The value of the fresh component parts of the plant and the fresh pods was estimated and this represented the biomass yield. The harvester pods were cut open longitudinally and fermented for seven days in the open air. The seeds were thereafter removed from pods and washed, and then dried to determine the dry weight of melon seed. 3 Results and Discussion 3.1 Soil physical properties Bulk Density The average value of the soil bulk density of the No-till, Primary tillage and Secondary tillage plots is presented in Table 2. The bulk density was highest in plot under No-till treatment, followed by Ploughed field and the lowest average bulk density was recorded in plots under secondary tillage system (Ploughed and Harrowed field) with average values 1.55g/cm 3, 1.3g/cm 3 and 1.15g/cm 3, respectively. The highest bulk density value (1.53 g/cm 3 ) was recorded at cm soil depth in soil under No-till. The high value of soil bulk density at the surface soil layer (0-10 cm) might be due to non-disturbance of soil system, which resulted in lower total porosity of 34.42% compared to tilled plots. Trends in soil bulk density are generally considered a rough approximation of soil structural changes (Liebig et al., 2004). The bulk density obtained from this study agrees with the findings of several other researchers who reported higher bulk density under no-till at the soil surface compared with tilled soil (Wu et al., 1992; Hill, 1990; Klute, 1982). Tillage loosens the soil and decreases soil macro porosity (Hill et al., 1985; Vazquez et al., 1991). 210

5 3.1.2 Soil Porosity Considerable influence of tillage on physical properties such as total porosity, micro porosity, and macro porosity of the soil was noticed as shown in Table 3. The total porosity at depth cm was highest (47.38%), the highest macro porosity (38.26%) was obtained at the cm depth while the highest micro porosity (11.59%) was obtained at the 0-10 cm soil depth on no-till; the total porosity at depth 0-10 cm was highest (61.77%). The highest macro porosity (56.07%) was obtained at the 0-10 cm soil depth, while the highest micro porosity (5.7%) was recorded at the 0-10 cm soil depth in primary tillage. In plots under secondary tillage system, the highest total porosity (59.81%) was obtained at cm soil depth, and the highest macro porosity (49.06%) and micro porosity (10.75%) were obtained at the cm soil depth. Similar observation was made by Rahman et al. (2008) on physical, chemical and microbiological properties of Andosol in relation to land use and tillage reported that total porosity was significantly greater in conventional tillage. Glab and Kulig (2008) also documented the influence of tillage on soil porosity. These researchers reported increased in total porosity in soil under tillage. Also Elder and Lal (2008) observed a general trend of total porosity of soil under ploughed field Soil Moisture Content The soil moisture content in the three treatments is represented in Figure 1. The soil moisture content increased from 10 cm to 30 cm depth for the three plots. The moisture content was highest in plots under secondary tillage system (10.9%) and lowest in No-till plots (8.5%). The result obtained show that the moisture content increases with increase in depth. The highest moisture content recorded under the secondary tillage treatment must have been caused by enhanced the total porosity, macro and micro porosities as a result of improved soil tilt and loose pores. The larger pores within the soil system in plots under primary and secondary tillage systems influenced water retention down the soil profile. 3.2 Agronomic measurement Vine Length Table 4 shows the changes in the vine length of melon plant with time. The initial average length of melon after 8WAP no-till, primary and secondary tillage plots were 224 cm, 223 cm, and 267 cm, respectively. The maximum height recorded in plot under no-till was 224 cm and the highest plant length (267 cm) was recorded in plot under secondary tillage. The plant length in the secondary tillage plot was about 19.73% and 19.19% higher than the observed values in plots under primary and no-till, respectively Number of Leaves of Melon on Soil The leaves number result is shown in Table 5. From the graphs, it is clearly seeing that in the treatment, adequate water is required for the increase in the performance in term of development and yield. But rapid change was noticed at the 8WAP where there were increase in leaf count from 60 to 131 under the no-till, from under the primary tillage and from in the plot under secondary tillage, respectively. The highest number of leaves in plot under secondary tillage must have caused by enhance root penetration and the eventual greater access to water within the deeper layer of soil (Lipiec et al., 1991). Table 5: Mean (STD) of Number of Leaves on function of Week after Planting Root depth 211

6 Nigeria The highest root depth was observed in the secondary tillage (34 cm) during the 8WAP. This result is in agreement with the findings of khan et al (2001), who concluded that tillage practices produce a favourable environment for crop growth and nutrient use. The result is also in line with that reported by Rashidi and Keshavarzpour (2007) that annual disturbance and pulverizing caused by tillage practices produce a finer and loose soil structure which in turn affect the seedling emergence, plant population density and consequently crop yield. The lowest root depth was observed in the no-till plot (13 cm) during the 8WAP. The result is in agreement with the findings of Hemmat and Taki (2001), that no-tillage method in arid regions had an adverse effect on crop yield. The root development was responsible for highest water and nutrient uptake, and hence the crop growth and yield Leaf area, leaf coverage area and leaf area index The leaf area, leaf coverage area and leaf area index of melon in No-till, Primary and Secondary tillage are presented in Tables 7, 8 and 9, respectively. There was an increase in the leaf area of melon throughout the growing season of the crop. However, highest leaf area was observed in Secondary tillage ( m 2 ) and lowest leaf area was observed in the Notill ( m 2 ). There was clear difference in leaf areas observed under the different tillage treatments. However, leaf areas were lower during the vegetative stage of the crop comparatively with the maturity stage of the crop Melon seed yield under the different tillage treatments The seed yield of melon over the three different tillage treatments is presented in Table 10. The highest seed yield (0.68 tonha -1 ) was recorded in plots under No-Till treatment. Though, one of the plots under primary tillage treatment had higher seed yield when compared to the yield under secondary tillage, the mean of seed yield for the different tillage systems showed that the yield in plots under secondary tillage had higher seed yield (0.47 ± 0.04 tonha -1 ) than yield under primary tillage (0.44 ± 0.10 tonha -1 ). The crop under No-Till must have benefitted from the residue cover of dead plant leaves, which consequently must have increased the organic matter content of the soil (Fasinmirin and Reichert, 2011). Multiple comparisons of mean of seed yield for the different tillage treatments showed that the mean difference between the No-Till and the primary tillage treatment plots was significant (0.35 * ) at the 5% probability level (Table 11). However, no significant mean difference was recorded between the No-Till and primary tillage (0.69 ns ), and between the primary and secondary tillage systems (0.63 ns ) 4. Conclusion Tillage method significantly affected crop yield of melon in order NT>ST>PT. The highest amount of crop yield obtained in the NT method might be due to plant residue cover on the soil which enhanced the soil structure and suppressed weed growth despite the higher bulk density. It is very uneconomical and detrimental to use heavy duty machines such as tractor for soil tillage in melon production considering the costs, compaction effects on soil as well as the associated reduced yield. 212

7 References Bakr, E., A new software for measuring leaf area and area damaged by tetranychus urticae Koch. J. Applied Entomol., 129; Bauder, J.W., G.W. Randall and J.B. Swan, Effects of four continue tillage systems on mechanical impedance of a clay-loam soil. Soil Sci. Soc. Am. J., 45: Blake, G.R., Hartge, K.H., (1986). Bulk density. In: A. Klute (Ed.). Methods of Soil Analysis. Part I. Physical and Mineralogical Methods. 2nd. Ed., Agronomy No. 9 (part I). ASA-SSSA. Madison, Wisconsin, USA, Cannel, R.Q., Reduced tillage in north-west Europe. A Rev. Soil and Tillage Res., 5: Chaudhary, A.D., M. Javed, M.A. Rana, A. Sarwar and Q. Zaman, Comparative performance of direct drilling and conventional tillage practices under rice-wheat rotation system. Pak. J. Agric. Sci., 29: 5-8. D Haene, K., J. Vermang, W. M. Cornelis, B.L.M. Leroy, W. Schiettecatte, S. De Neve, D. Gabriels, G. Hofman Reduced tillage effects on physical properties of silt loam soils growing root crops. Soil & Tillage Res. 99, Elder, J.W., Lal, R., 2008.Tillage effects on physical properties of agricultural organic soils of north central Ohio. Soil Till. Res. 98, Fasinmirin J.T. and S. Konyeha (2009). Evaluation of some hydraulic characteristics of furrow irrigation system in a cassava Manihot esculenta crantz field. Journal of Applied Irrigation Science. Zeitschrift für Bewässerungswirtschaft, 44. Jahrg., Heft, 1 /2009, ISSN Vol 44, No 1, pp Fasinmirin J.T., Olufayo, A. A., Oguntunde, P. G. and Oguntuase. A.M. (2009). Parametrizing Simple Model between Yield and Evapotranspiration for Amaranthus cruentus under Drip and Sprinkler Irrigations. International Journal of Plant Production. Gorgan University of Agricultural Sciences and Natural Resources. (ISSN: (Print), ) Vol 3(1). pp75-90 Fasinmirin, J,T and Olorunfemi, I.E. (2012). Comparison of Hydraulic Conductivity Characteristics of Soils of the Forest Vegetative Zone of Applied Tropical Agriculture. Vol. 17, Nos 1, pp Fasinmirin, J. T., 2007: The Response of Amaranthus cruentus L. to Water Application Using Drip and Sprinkler Irrigation Systems. - Unpublished PhD Thesis, Federal University of Technology, Akure, Nigeria, Fasinmirin, J.T. and Reichert, J.S. (2011). Conservation Tillage for Cassava (Manihot esculenta crantz) Production in the Tropics. Soil and Tillage Research, Elsevier Science B.V., 113: Fasinmirin, J.T., Adesigbin, A.J. (2012). Degree of Compaction and Compression Strength of Nigerian Alfisol Under Tilled Condition and Different Machinery Traffic Passes. Int. J. Agric and Biol. Eng. Vol. 5 No 2. pp Glab, T., Kulig, B Effect of mulch and tillage system on soil porosity under wheat (Triticum aestivum). Soil & Tillage Research, Amsterdam, 99: Gong, P., Ruiliang, Pu, and Miller, J.R. (1995): Coniferous Forest Leaf Area Index Estimation along the Oregon Transect Using Compact Airborne Spectrographic Imager Data, PE & RS, 61 9: Hammel, I.E., Long term tillage and crop rotation effects on bulk density and soil impedance in north emldaho. Soil Sci. Soc. Am. I., 53: Hemmat, A. andd. Taki, Grain yield of irrigated wheat as affected by stubble tillage management and seeding rates in central Iran. Soil and Tillage Res., 63:

8 Nigeria Hill, R.L., Long-term conventional and no-tillage effects on selected soil physical properties. Soil Sci. Soc. Am. J., 54: Hill, R.L., R. Horton, and R.M. Cruse Tillage effects on soil water retention and pore size distribution of two mollisols. Soil Sci. Soc. Am. J. 49: Home, D.J., C.W. Ross andk.a. Hughes, Ten years of maize/oats rotation under three tillage systems on a silt-loam soil in New Zealand. 1. A comparison of some soil properties. Soil and Tillage Res., 22: Iqbal, M., A.U. Hassan, A. Ah and M. Rizwanullah, Residual effect of tillage and farm manure on some soil physical properties and growth of wheat (Triticum aestivwn L.). Intl. I. Agric. Biol., 1: Khan, F.U.H., A.R. Tahir andl.j. Yule, Impact of different tillage practices and temporal factor on soil moisture content and soil bulk density. Intl. J. Agric. Biol., 3: Khan, F.U.H., A.R. Tahir andl.j. Yule, Intrinsic implication of different tillage practices on soil penetration resistance and crop growth. Intl. J. Agric. Biol., 1: Khurshid, K., M. Iqbal, M.S. Arif and A. Nawaz, Effect of tillage and mulch on soil physical properties and growth of maize. Intl. J. Agric. Biol., 5: Klute A (1982). Tillage effects on the hydraulic properties of soil: a review. In: Unger, P.W., Van Doren, Jr., D.M. (Eds.), Predicting Tillage Effects on Soil Physical Properties and Processes, ASA Spec. Publ. No. 44. ASA, Madison, WI, pp Lal, R, Tillage effects on soil degradation, soil resilience, soil quality and sustainability. Soil and Tillage Res., 51: Liebig, M.A., Tanaka, D.L., Weinhold, B.J., Tillage and cropping effects on soil quality indicators in the northern Great Plains. Soil and Tillage Research 48, Rahman, M. H., Okubo, A., Sugiyama, S., Mayland, H.F Physical, chemical and microbiological properties of an Andisol as related to land use and tillage practice. Soil & Tillage Research 101, Raper, R.L., Reeves, D.W., Burmester, C.H., Schwab, E.B., Tillage depth, tillage timing, and cover crop effects on cotton yield, soil strength, and tillage energy requirements. Appl. Eng.Agric. 16 (4), Rashidi, M. and F. Keshavarzpour, Effect of different tillage methods on grain yield and yield components of maize (Zea mays L.). Intl. I. Agric. Biol., 2: Soil Survey Staff Keys to soil taxonomy. 8th ed. USDA, Washington D.C. Suzuki, L. E. A. S., D. J. Ranert, and J. M. Reichert Degree of compaction for notillage soils: reference bulk density and effects on soil physical properties and soybean yield. Vazquez,L.,Myhre,D.L.,Hanlon,E.A.,Gallaher,R.N.,1991.Soil penetrometer resistance and bulk density relationships after long-termnotillage.commun.plantanal.22, Wu, L., Swan, J. B., Paulson, W. H., Randall, G. W. (1992). Tillage effects on measured soil hydraulic properties. Soil and Tillage Research, 25(1):

9 Table 1 Summary of agronomic measurements conducted during the experiment S/No Measurements Frequency Treatment Remark 1 Vine length Every week Samples from Measurements were taken from each treatment the base of the stem to the longest fully emerged leaf 2 Number of Every week Samples from By counting Leaves each treatment 3 Leaf area Every week Samples from By using Compu Eye leaf area 4 Biomass yield Once at plant maturity each treatment Samples from each treatment Table 2: Mean bulk density from plot A, B, and C at different depths. Plots 0-10cm 10 20cm 20 30cm No-till 1.705g/cm g/cm g/cm 3 Plough Plot 0.994g/cm g/cm g/cm 3 Plough and Harrow 1.180g/cm g/cm g/cm 3 software By weighing fresh and dry plant parts Table 3: Shows the Total, macro and micro porosity of the site Depth (cm) No-till Primary tillage Secondary tillage Total Porosity (%) Micro porosity (%) Macro porosity (%) Table 4: Shows the length of Melon at Various Weeks After Planting PLOTS 2nd 3rd 4 th 5th 6th 7th 8 th No-Till Primary Tillage Secondary Tillage

10 Nigeria Table 5. Number of leaves Plots Weeks After Planting (WAP) 2 nd 3rd 4th 5 th 6th 7th 8 th NT 12 (±2.14) 19 (±5.22) 28 (±3.77) PT 17 (±1.67) 25 (±4.27) 33 (±4.22) ST 27 (±3.83) 36 (±1.57) 44 (±2.02) 37 (±2.11) 43 (±3.78) 52 (±1.67) 45 (±1.66) 60 (±2.54) 56 (±2.98) 97 (±1.79) (±1.97) (±2.52) 131 (±2.58) 166 (±2.07) 594 (±3.47) Table 6: Mean (STD) of root length of melon (cm) on function of weeks after planting PLOTS Weeks After Planting (WAP) 2 nd 3 rd 4 th 5 th 6 th 7 th 8th NT 2.9 (±1.54) 3.8 (±2.11) 5.6 (±1.09) 7.0 (±0.87) 8.0 (±1.23) 11.7 (±2.41) 13.0 (±0.96) PT 4.3 (±2.13) 5.7 (1.39) 7.2 (±2.49) 9.8 (±1.99) 12.6 (±1.87) 16 (±3.21) 19.0 (±2.21) ST 5.1 (±2.41) 6.6 (±1.74) 8.6 (±2.05) 10.1 (±1.68) 13.5 (±1.07) 21.9 (±2.25) 34.0 (±1.85) Table 7: Leaf area of melon in No-till, Primary and Secondary tillage. WAP No-till Primary tillage Secondary tillage MEAN SD (±) * SD-Standard deviation Table 8: Leaf Coverage Area (m 2 ) WAP No-till Primary tillage Secondary tillage MEAN SD (±)

11 Table 9: Leaf Area Index WAP PS No-till Primary tillage Secondary tillage MEAN SD (±) *WAP-Week after planting, LCA-Leaf coverage area, LAI-Leaf area index, SD-Standard deviation, PS Sampled Plant Table 10. Seed yield (tonha -1 ) of Melon for the different tillage treatments Treatments No-Till Primary Tillage Secondary Tillage Replicate Replicate Replicate Mean SD ±0.07 ±0.10 ±0.04 SD Standard Deviation Table 11. Multiple Comparisons of Mean of Seed Yield (LSD = 0.05) Treatment I Treatment J Mean Significance Difference No-Till Primary Tillage * No-Till Secondary Tillage ns Primary Tillage Secondary Tillage ns * The mean difference is significant at the.05 level Moisture Content (%) PLOT A PLOT B PLOT C WAP (per week) Figure. 1: Moisture content of plot A, B and C from 4 th to 8 th *Plot A No-till; Plot B Primary Tillage; Plot C Secondary Tillage 217