Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria.

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1 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu, A.A. 1*, Opara-Nadi, O.A. 1 and Kamalu, O.J. 2 1 Department of Soil Science Abia State University, Umuahia, Nigeria. 2 Dept of Crop/Soil Science, Uniport. *corresponding author Abstract The effect of five land management options on the field performance of a cassava-maize intercrop was evaluated at Umudike in the rainforest zone of southeastern Nigeria. The land management options which were compared for four years ( ) were fallow-grazingcropping (FGC), traditional farming (TF), no-tillage (NT), minimum tillage (MT) and conventional tillage (CT). The treatments were laid in a randomized complete block design (RCBD) with three replications. The results showed that in 2004, NT and MT produced the highest bulk density of 1.62 Mg/m -3, while FGC produced the lowest bulk density of 1.58 Mg/m-3 which was not significantly different from the highest. Total porosity and volumetric moisture content were significantly higher for FGC than MT and CT. In 2006, while bulk density was significantly higher in CT treatment compared to the FGC, TF and MT treatments, total porosity and volumetric moisture content were lower for CT when compared with the other management practices. Soil ph, organic carbon, and total nitrogen all showed significant differences amongst the treatments for both years. Mean seedling establishment of maize was of the order FGC > CT > NT > MT > TF, with the difference among the treatments being significant in some years. Treatment effect on maize plant height was also significant. Cassava seedling establishment and cassava plant height were significantly affected by land management. Grain yield of maize was statistically lowest under TF treatment throughout the study period. Tuber yield of cassava was significantly higher for CT and FGC for most of the years. The overall results highlighted the importance of good seedbed preparation which is different for grain and tuber crops. 1. Introduction Maize and cassava are amongst the most widely consumed food items in Nigeria and some other parts of sub-saharan Africa, beside their industrial uses. Maize is a major feed ingredient in the poultry industry, while cassava is extensively used in the starch industry. It has also been reported that Nigeria is moving toward a thirty percent cassava flour inclusion in bread. However, despite the increasing demand for these two crops, their production is by peasant farmers who use manual labour to cultivate minimal hectarages in a mixed cropping system on fragile soils, which are developed from unconsolidated materials (Kogbe, 1975). Eco-physical perturbation associated with land preparation in most of the maize-cassava production area when not properly handled often leads to irreversible environmental degradation with attendant low crop yield. Consequently, appropriate land and soil management practices are not only critical in optimizing soil productivity but also a pre-requisite for sustainable land use. In Southeastern Nigeria and other parts of the humid tropics,the most predominant soil management practices include fallowing and tillage (Babalola and Opara-Nadi, 1993). Fallowing involves the practice of leaving the soil without crops for some period to enable it regain fertility. 227

2 Soil fertility regeneration under the traditional farming system relies on the length of fallow period and type of vegetation (Aweto, 1981). However, with increasing population, fallow periods have become drastically reduced to the point that it no longer keeps the soil fertile (Tian et al., 1999). The enhancement of the natural vegetation by the introduction of fast growing plants/shrubs is an attractive approach for shortening the fallow period and increasing the yield of subsequent crops (Juo and Lal, 1977; Gichuru, 1991). Such fallows can be further improved by the introduction of animals that graze on the vegetation and also add manure to the soil (Ikpe and Powell, 2002). Tillage involves any positive action where forces are reasonably applied with the aim of altering the soil condition for agricultural purposes (Afolayan et al.,2005). Babalola and Opara-Nadi (1993) recognized five types of tillage systems used in Southeastern Nigeria as the traditional tillage, plough-till, minimum till, no-till and pudding and compaction. Tillage effects on the soil may be both beneficial and degradative depending on the appropriateness or otherwise of the system used (Ofori, 1993; Opara-Nadi, 1993). Appropriate tillage practices are those that avoid the degradation in soil properties but crop yields as well as ecosystem stability (Lal, 1985) and conserve the resource base on which the production depends (Young, 1989). Soil organic matter (SOM) is a key component of sustainable agricultural systems and is highly dependent upon appropriate soil and crop management practices, which influence ecosystems cycles of carbon, nitrogen and other elements (Usiri and Johnson, 2003; Omonode et al., 2006). The effect of soil management practices has been studied by several workers, with results most times, being contradictory. Information on the effect of crop and soil management practices on the performance of maize-cassava intercrop in Southeastern Nigeria is scanty despite the importance of these crops in the overall agricultural production system. Thus, the aim of this study was to evaluate the effect of different tillage systems and fallow-grazing-cropping on some soil properties and the growth and yield of cassava-maize intercrop in Umudike, Southeastern Nigeria. 2.1 Location and Site Environment The 4-year study was carried out at the Teaching and Research Farm of the Abia State University, Umudike in Abia State located between ' N and ' E in the rainforest ecological zone of southeastern Nigeria. The zone is characterized by two distinct seasons; the wet season from April to October and the dry season from November to March. The mean annual rainfall ranges between 1800 and 2000 mm with a bimodal pattern. The soil which is derived from coastal plain sediments has been classified as ultisol (Soil Survey Staff, 1999) and Acrisol (FAO/UNESCO) (Opara-Nadi 2000). Some physical and chemical properties of the 0 20 cm soil depth in the experimental site are shown in Table Site Preparation and Treatment The site was manually cleared by slashing in March The experimental design was randomized complete block design (RCBD) with five treatments replicated three times, giving a total of 15 plots. Each plot measured 10 x 8 meters with a-2- meter boarder. The blocks were separated by a-3-meter boarder. 228

3 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al The treatments were no-tillage (NT), minimum tillage (MT), conventional tillage (CT) traditional farming (TF) and fallow-grazing-cropping (FGC). The NT treatment involved no disturbance of any form on the land. MT involved ploughing the soil once with a disc plough to a depth of about 20 cm, while the CT treatment involved disc ploughing followed by harrowing, while TF treatment entailed slashing and burning of the trash, with planting done on flats. The FGC treatment involved the establishment of planted fallow (guinea grass, Panicum maximum, with liberal supply of Centrocema pubecense) in the first year (2003), introduction of four adult West African Dwarf goats in the second year (2004) to graze on the fallow, and the planting of crops in the third and fourth years (2005 and 2006) of the study. All tillage and planting operations were done in April each year. The planting distances were 1m x 1m and 50 cm x 50 cm, giving a plant population of 10,000 and 20,000 plants per hectare of cassava and maize respectively. Cassava variety, NR8082 and maize (Zea mays L, Oba Super) were used, being well adapted to the environment. The plots were sprayed with a mixture of paraquat (1-1, dimethyl bipyridilum ion) at 2.5 litres ha -1 and altrazine (2-chloro-4- ethylamino-6-isopropyl-amino-1,3,5 triazine) at 2 kg ha -1 as pre-emergent herbicides. Subsequent weed controls were done by hoeing. Fertilizer application was at the rate of 400kg ha -1 of 15:15:15 (NPK) in split application, using ring method. The first spilt was applied 4 weeks after planting, while the second was given at the tasselling stage of the maize. 2.3 Sample Collection All observations and data collection were made in accordance with the Tropical Soil Biology and Fertility (TSBF) programme Handbook of Methods as described by Anderson and Ingram (1989). Soil samples were collected from 0 20 cm depth from each plot at the end of each cropping season. The soil samples were air dried and sieved through a 2 mm sieve. Three undisturbed core samples were also collected from the same depth from each plot with core cylinders measuring 5 cm long and 5 cm internal diameter for the determination of bulk density. Data were collected on seedling establishment, plant height, tuber yield of cassava and grain yield of maize 2.4 Soil Analysis Particle size analysis was done by hydrometer method (Juo, 1979). Bulk density determination was by the core method (Blake, 1965). Total porosity was calculated from the bulk density and an assumed average particle density of 2.65 kg m -3 using the equation (1). P = (1 ρ b /ρ p ) x 100% (1) where: P = total porosity (%) (m 3 m -3 ) ρ b = bulk density (Mg m -3 ) ρ p = Particle density (2.65 Mg m -3 ) Soil ph in water was determined with a Pye-Unican-Model 290 MK2 ph meter. Organic matter was determined by the wet-oxidation method of Walkley and (Black, 1939) as modified by Juo (1979).) The determination of exchangeable cations (bases) was carried out using the EDTA 229

4 titration method and flame photometry methods as described by Chapman (1965), while total nitrogen was obtained by the semi-micro kjeidahl method (Bremner, 1965). Exchangeable acidity was determined after extracting with 1N KCl and titrating with NaOH. 3. Results and Dicussions 3.1 Soil Properties The physico-chemical properties of the soil of the experimental site are as shown in Table 1. The soil was acidic with a ph value of 5.3 probably due to the nature of the parent material and excessive leaching. Organic carbon, total nitrogen, available P and exchangeable cations were low. The low organic carbon content can be attributed to the high rate of decomposition, while low nitrogen content and available P is traceable to the low organic carbon content. The low exchangeable cations sterns from the type of clay and the highly weathered and leached nature of the soil (Lekwa and Whiteside, 1986). Exchangeable acidity dominated the exchange complex Effect of land management practices on soil physical properties Table 2 shows the effect of land management practices on the physical properties of the 0 20 cm depth of the soil. (a) Soil bulk density, BD was significantly higher (P=0.05) under the conventional tillage, CT, treatment in 2005 and 2006 than the other management practices. Except in 2004 when the lowest bulk density of 1.58 Mg m -3 was recorded under the FGC treatment, MT treatment consistently had the lowest bulk density. This could be explained by the loosening of the soil by the tillage implement with minimal compaction. Stockfisch et al. (1999) had reported lower bulk density in MT plots than for NT and CT plots. The relatively lower bulk density of the FGC treatment in 2004 may have been occasioned by the increased organic carbon arising from the wastes from the goats (Table 3). Chanasyk and Naeth (1996) reported soil compaction by grazing animals. Considering the observed results in this study, it can be seen that trampling and compaction of soil by the grazing goats were minimal, while organic matter addition from animal faeces and urine may have had an overriding influence on the bulk density than the compaction caused by the grazing animals. (b) Soil total porosity (TP) was significantly affected (P=0.05) by land management practices as shown in Table 2. Total porosity was consistently lower under the CT plots except in 2003 when NT treatment recorded the lowest total porosity. The low TP of the CT plots is attributed to the compaction caused by the repeated tractor movement over the plots. In 2003 and 2004, TP was highest under FGC plots, while in 2005 and 2006, MT recorded the highest TP. Data on Table 2 showed that TP followed the same pattern as BD. (c) Volumetric moisture content (VMC) was also significantly affected (P=0.05) by land management (Table 2). The non-cultivation of the FGC plots in 2003 and 2004 and the improved soil total porosity over the same period resulted in higher VMC when compared against the other treatments. The minimal disturbance of the pore-geometry of the NT plots can account for the higher VMC of these plots, including the FGC plots. Furthermore, the addition of organic carbon in the FGC plots must have resulted in better soil aggregation and reduced bulk density. The low VMC associated with the CT management practice indicates reduced moisture storage capacity as a result of increased bulk density and reduced total porosity. 230

5 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al Generally, soil texture was not affected by management practices (Table 2). This is in agreement with the report of Afolayan et al. (2005). However, there was a reduction in clay content under the CT treatment from 18.0% (initial clay content) to 10.2%. This could be attributed to water erosion which may have preferentially removed more clay particles than silt and sand from the CT plots Effect of land management on soil chemical properties Data on the chemical properties of the 0 20 cm soil depth are as shown in Table 3. Soil ph was significantly higher (P=0.05) for TF than the other management practices in Also, TF recorded the highest ph value in 2006, though the differences were not significant. The relatively higher ph associated with this treatment could be explained by the burning which had given rise to higher Ca and K contents in the TF plots. Both organic carbon, OC and total nitrogen, TN were significantly affected (P=0.05) by management practices at both sampling periods. In 2004, FGC treatment recorded the highest OC (1.54%), while TF had the lowest (1.18%). The low OC content of the TF plots was due to the burning of the debris. Total N was similar amongst NT, MT and CT. The trend for both OC and TN in 2006 was similar to the trend in The relatively higher OC content of the MT and CT in comparison with the TF and NT treatments could be due to the over turned plant residues (Mahboubi et al., 1993). Available P was significantly lower (P=0.05) under the FGC treatment when compared with the tilled plots in 2004, while there was no significant difference in available P among the treatment in However, the highest amount (24.5mg/kg) was recorded under the CT, while the lowest (22.8mg/kg) was recorded the NT treatment. In 2004, exchangeable cations were affected by management practices. Exchangeable Ca, K and Mg were significantly higher (P=0.05) for FGC than MT. Again, Ca was higher for FGC and TF than the other treatments. Exchangeable K and Na were higher in the untilled plots than the tilled plots. In 2006, the untilled plots were significantly higher (5%) in Ca when compared with the tilled plots. TF and NT treatments were statistically higher than both MT and CT plots in exchangeable K. The lower exchangeable cations in the tilled plots can be attributed to higher mineralization rates following the mixing of the organic matter and the soil which may have provided more favourable conditions for the activities of soil microorganisms and subsequent leaching loses. Rhoton et al. (1993) established higher exchangeable Ca, Mg and K in the NT treatment compared to CT treatment and attributed this to non-mechanical incorporation of soil amendments and the more exposure of soil under CT to far more erosion loses than those under NT. On the average, concentrations of exchangeable cations were of the order Ca > Mg > K > Na, reflecting the decreasing energy of adsorption by the clay complex (cations with higher valence are more strongly adsorbed than those with lower valence). It also reflected the increasing mobility of ions in the soil solution. The highest exchangeable acidity (3.68 Cmol Kg -1 ), which was significantly than the others, except NT treatment, occurred in the TF treatment, while the lowest (3.03 Cmol Kg -1 ) occurred in the MT plots, in In 2006, TF and NT plots were statistically higher in exchangeable acidity when compared with FGC, MT and CT. The high exchangeable acidity recorded in the TF plots in both years, despite having the highest ph (5.7) suggests that exchangeable aluminum accounted for higher percentage of exchangeable acidity in these plots. 231

6 3.2 Effect of Management Practices on Crop Performance Maize growth and grain yield (a) Seedling establishment Effect of management practices on seedling establishment of maize is as shown in Table 4. Seedling establishment was significantly (P=0.05) affected by management in all the years, except in In 2003, seedling establishment for NT treatment was higher by 3, 5 and 1% than TF, MT and CT respectively. In 2005 and 2006, FGC treatment recorded the highest seedling establishment when compared with the other treatments, the difference being significant only against TF and NT. The higher maize seedling establishment of the NT treatments in 2003 could be attributed to the excellent seed-soil contact under this system, while the performance of the FGC treatment could be related to the improved fertility of the soil (Table 3) as a result of fallowing and dropping of animal wastes (Ikpe and Powell, 2002). (b) Maize plant height Maize plant height at 6 and 10 weeks after planting (WAP) was significantly (P=0.05) affected by management practices. Except in 2005, maize plant height was significantly higher for tilled plots than NT and TF. At 10 WAP, CT recorded the highest maize plant height of and cm in 2003 and 2004 respectively, while TF recorded the lowest over the same period ( 46.5 and 39.1 cm respectively). While NT recorded the highest plant height increment (between 6 th and 10 th week) in 2003, CT treatment had the highest in Maize plant height at 10 WAP in 2005 was significantly highest for FGC when compared with the other treatments but was similar to CT in The better performance of the tilled plots over the untilled plots in 2003 and 2004 could be due to the higher organic carbon contents of these plots, while the superior performance of the FGC is attributable to the fallow and animal effect. (c) Maize grain yield Data on Table 4 shows the effect of management practices on grain yield of maize. Maize grain yield was significantly affected by management practices over the years under study. TF treatment consistently gave significantly lowest yield in all 4 years. This can be attributed to the harmful effect of burning, which is a component of the traditional farming system. In 2003 and 2004, MT and NT were respectively higher, though not significant, when compared with the other treatments, except in TF where the difference was significant. In 2005 and 2006, yield of maize was highest under the FGC management with the differences being insignificant in comparison with the other treatments, except for TF. The relatively good performance of the NT practice is consistent with the findings of Ojeniyi and Adekayode (1999) who explained the observation in terms of the conserved fertility by NT treatment Cassava growth and fresh tuber yield (a) Cassava seedling establishment Table 5 contains data on cassava seedling establishment. Cassava seedling establishment for 2003 and 2004 was not affected by management. However, MT gave the highest seedling establishment of 95.6% and 90.3% for 2003 and 2004 respectively. Lowest values of 92.7 and 88.4% were associated with TF plots in 2003 and 2004 respectively. In 2005 and 2006, cassava seedling establishment was significantly higher (P=0.05) for FGC and CT when compared with the other treatments. The higher seedling establishment under tilled plots suggests that loosening 232

7 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al of the soil favours cassava seedling establishment, probably due to improved aeration, while improved fertility can account for the higher values of the FGC treatment. (b) Cassava plant height. Results of cassava plant height measured at 8, 12 and 16 WAP are shown in Table 5. Land management practices significantly affected cassava plant height in all the years and at all times of evaluation. In 2003, cassava plant height was greater by 8, 30 and 14% for CT than TF, NT and MT respectively at 8 WAP. For the other years and at 8 WAP, TF treatment recorded the highest plant height. This observed performance of the TF plots is attributable to the higher amounts of Ca and K arising from the ash added by the burning. At 12 WAP, cassava plant height was significantly higher for FGC treatment than the other treatments. Similarly, CT was statistically higher than TF, NT and MT. The reduced height increment observed in the TF treatment beyond 8 WAP highlights the need to plant shortly after burning to be able to take full advantage of the nutrients added by the ash. Cassava plant height measured at 16 WAP showed that CT treatment gave the highest values of 65.5 and 66.1 cm in 2003 and 2004 respectively. These values were significantly higher than those recorded for NT (53.1 and 57.8 for 2003 and 2004 respectively). In 2005, land management practice increased cassava plant height in FGC by 39, 27, 42 and 13% over TF, NT, MT and CT respectively. In 2006, the order was FGC > CT > NT > TF > MT. (c) Cassava fresh tuber yield. Data on cassava fresh tuber yield are as shown on Table 5. Land management practices affected cassava fresh tuber yield significantly (P=0.05).In 2003 and 2004, tilled plots out-yielded untilled plots, with significant difference over TF in In 2004, CT was also statistically higher than TF. In 2005 and 2006, FGC management was significantly superior to the other treatments except CT. In 2005, FGC practice increased cassava fresh tuber yield over TF, NT, MT and CT by 54.5, 38.7, 27.5 and 14.3% respectively, while in 2006, it out yielded TF, NT, MT and CT by 51.0, 35.7, 21.8 and 10.2 respectively. The best performance of the FGC plots is explained by the fallow effect and the wastes from the animals. Conclusion The fertility of the soils of the study area can be sufficiently improved within one year of improved fallow management in combination with application of animal wastes. Traditional farming which involves slashing and burning of refuse, though not environmentally friendly, has some benefits which are best derived if planting is done shortly after burning. Maize production on ultisols in the southeast ecological zone of Nigeria can thrive under notillage management. Grain yield of maize was higher under NT and MT practices than under CT practice, whereas fresh tuber yield of cassava was higher under CT and MT management practices than NT. This observation emphasizes the importance of good seedbed preparation which is different for grain and tuber crops. 233

8 References Afolayan, S.O., Babalola, O. and Igbeka, J.C. (2005). Tillage systems and their effect on some soil properties, crop growth and shoot yield of grain-amaranth. AMA. Agricultural Mechanization in Asia, Africa and Latin America. 36: Anderson, J.M. and Ingram, J.S.I. (1989). Tropical Soil Biology and Fertility: A Handbook of Methods. Walingford, U.K. : CAB International. Aweto, P.M. (1981). Secondary succession and soil fertility restoration in southwestern Nigeria. III. Soil and vegetation interrelationships. J. Eco. 69: Babalola. O. and Opara-Nadi O.A. (1993). Tillage systems and soil properties in West Africa. Soil Tillage Res. 27: Blake, G.R. (1965). Bulk density. In: Black C.A. (ed.). Methods of Soil Analysis. Part I. Physical and Mineralogical Properties. Soil Sci. Soc. Am. Madison. WI. pp Bremner, R. (1965). Fabric and Mineral Analysis of Soils. John Willy and Sons Inc. New York. Chanasyk, D.S. and Naeth, M.A. (1996). Grazing impacts on bulk density and soil strength in the foothills fescuc grassland of Alberta, Canada. Can. J. Soil Sci. 75: Chapman, H.D. (1965). Cation exchange capacity. In: C.A. Black (ed). Methods of Soil Analys, Part 2. Agron. 9. Am Soc. Agron., Madison, Wi Gichuru, M.P. (1991). Residual effects of natural bush, Cajanus cajan and Tephorosia candida on the productivity of an acid soil in southeastern Nigeria. Plant and Soil 134: Ikpe, F.N. and Powell, J.M. (2002). Nutrient cycling practices and changes in soil properties in the crop-livestock farming systems of Western Niger Republic of West Africa. Nutrient Cycling in Agro-ecosystems 62: Juo, A.S.R. and Lal, R. (1977). The effect of fallow and continuous cultivation on an Alfisol in western Nigeria. Plant and Soil. 47: Juo, A. S. R Selected methods for soil and plant analysis. IITA Manual Series No. 1. Kogbe, C.A. (1975). The cretaceous and paleocene sediment of southern Nigeria. In: C.A. Kogbe (ed.). Geology of Nigeria. Elizabethan Publishing Company, Surulere, Lagos. Lal, R. (1985). No-till in the lowland humid tropics. In: The Rising Hope for our Land Conference, Georgia, USA. pp Lekwa, G. and E. P. Whiteside Coastal Plain Soils of Southeastern Nigeria. Morphology, classification and genetic relationship. Soil Sci. Soc. Am. J. 50: Mahboubi, A.A., Lal, R. and Faussey, N.R. (1993). Twenty-eight years of tillage effects on two soils in Ohio. Soil Sci. Soc. Am. J. 57: Ofori, C.S. (1993). The challenge of tillage development in African agriculture. In: Soil Tillage in Africa: Needs and challenges. FAO soil Bulletin 69, Rome. Chapter 7: Ojeniyi, S.O. and Adekayode, F.O. (1999). Soil conditions and cowpea nd maize yield produced by tillage methods in the rainforest zone of Nigeria. Soil Tillage Res. 51: Omonode, R.A., Gal, A., Stott, D.E., Abney, T.S. and Vyn, T.J. (2006). Short-term versus continuous chisel and no-till effects on soil carbon and nitrogen. Soil Sci. Soc. Am. J. 70: Opara-Nadi, O. A. (1993). Conservation tillage for increased crop production. In: Soil Tillage in Africa: Needs and Challenges. FAO Soils Bulletin 69, FAO, Rome, Chapter 8 pp Opara-Nadi, O.A. (2000). Soil resources and agricultural productivity in Nigeria. In: L.C. Nwaigbo, U.H. Ukpabi and A. Anene (eds). Food and Fibre production in Nigeria in the 234

9 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al st century. Proc. of the First Annual Conference of the College of Agriculture and Veterinary Medicine Abia State University, Uturu. pp Rhoton, F.E., Bruce, R.R., Buchring, N.W., Elkins, G.B., Langdale, C.W. and Tyler, D.D. (1993). Chemical and physical characteristics of four soils under conservational and notillage systems. Soil Tillage Res. 28: Soil Survey Staff. (1999). Soil Taxanomy: A basic system of soil classification for making and interpreting soil surveys. USDA Agric Handbook No 436. Stockfisch, N., Forstreuter, T. and Ehlers, W. (1999). Ploughing effect on soil organic matter after twenty years of conservation tillage in Lower Saxony, Germany. Soil Tillage Res. 52: Tian, G., Kolawola, G.O., Salako, F.K. and Kang, B.T. (1999). An improved cover crop fallow system for sustainable management of low activity clay soils of the tropics. Soil Sci. 164: Usiri, D.A.N., and Johnson Ch. E. (2003). Characterization of organic matter in northern hardwood forest soil by 13C NMR spectroscopy and chemical methods. Geoderma 111: Young, A. (1989). Agroforestry for soil conservation. Wallingford, UK/Nairobi, Kenya: CAB International/ICRAF Walkley, A and Black, I.A. (1939). An examination of the Detgareff method for determining soil organic carbon, chronic titration method. Soil Sci. 37:

10 Table 1: Physico -chemical Properties Of The Experimental Site (0-20CM) Soil Parameter PH(H 2 O) 5.3 Org.C (%) 1.43 TN (%) 0.10 Avil.P (Mgkg -1 ) 24.0 Ca 0.96 Mg 0.10 K (Cmolkg -1 ) 0.08 Na 0.08 Exch-Acidity 2.56 ECEC 3.78 BS (%) 31.9 Sand (%) 71 Silt (%) 11 Clay (%) 18 BD (M 3 m -3 )

11 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al Table 2: Effect of Land Management practices on soil physical properties (0-20cm) Mgt BD+ TP++ VMC* BD TP VMC BD TP VMC BD TP VMC Sand Silt Clay ((Mgm - ((M 3 M- (Mgm- (M3m- (Mgm- M3m- (Mgm- (M3m- Practice 3 ) % 3 ) 3) (%) 3) 3) (%) 3) 3) (%) 3) % % % Textural Class FGC S L TF S L NT S L MT S L CT S L MEAN LSD Bulk density ++ Total porosity * Volumetric moisture content 237

12 Table 3: The Effect of Management Practices on Soil Chemical properties of the 0-20cm depth. Mgt. ph OC% Total N % Exch-cations Avil. Ca Cmol/kg P Mg K Na E.A ph OC% Total N% Avil. P Ca Mg Cmol/kg K Na E.A Pract. Mg/kg Mg/kg FGC TF NT MT CT LSD

13 Effect of Land Management Practices on Some Soil Properties and Field Performance of Cassava-Maize Intercrop in Umudike, Southeastern Nigeria. Omenihu et al Table4: Effect of Management Practices on Maize Growth and Yield Management Seedling Establishment (%) Plant Height (Cm) 6 WAP 10 WAP Grain yield (t/h Practice FGC TF NT MT CT MEAN LSD (0.05)

14 Table 5: Effect of Management Practices on Cassava Growth and Fresh Tuber Yeild. Mgt. Seedling Plant Height(Cm) TUBER Practice Establishment(%) (8 WAP) (12 WAP) (16 WAP) ( FGC TF NT MT CT MEAN LSD(0.05)