RESPONSE OF GRAIN AMARANTH ( AMARANTHUS CRUENTUS L . ) , TO METHOD AND RATE OF CATTLE KRAAL MANURE APPLICATION AT KADAWA AND SAMARU IN NIGERIA

Field experiments were conducted between June and October 2010 wet season at two different locations. The first was at the Horticultural Research Garden of the Institute for Agricultural Research (IAR), Samaru in the Northern Guinea Savanna agro-ecological zone and the second experiment was conducted at the Research Farm of the Irrigation Research Sub-Station (IRS), Kadawa in the Sudan Savanna agro-ecological zone also of the Institute for Agricultural Research, Ahmadu Bello University, Zaria, Nigeria to evaluate the response of grain amaranth growth and green edible vegetable yield components to three methods of cattle kraal manure application (broadcasting, side banding and spot placement incorporated) and five rates of cattle kraal manure application (0, 5, 10, 15 and 20 t ha), using the variety ‘Pure branch’. The experiment was laid out in a randomized complete block design (RCBD) and replicated three times. Cattle kraal manure application rates significantly (p > 0.05) increased growth of green edible vegetable yield characters of grain amaranth except stem girth at Samaru. Growth and green edible vegetable yield characters were generally not influenced by methods of cattle kraal manure application except for plant height, number of leaves per plant at 12 WAT at Samaru, and plant fresh weight at 12 WAT at Kadawa and dry weight at 4 and 12 WAT at Samaru and 12 WAT at Kadawa. Application of cattle kraal manure of 10 t ha to Amaranthus cruenthus gave the highest mean values which were comparable to those of 15 and 20 t ha rates for all the characters measured such as plant height, number of leaves, leaf area, fresh and dry weights. Thus, the finding suggests that 10 t ha should be recommended to farmers Corresponding author: e-mail: patrickokutu@yahoo.com Patrick Chiweta Okutu et al. 174 growing Amaranthus in the Northern Guinea and Sudan Savanna of Nigerian agro-ecologies.


Introduction
Grain amaranth is a nutritious vegetable and contains relatively high amounts of minerals and vitamins, which are needed for healthy body growth, sustenance and alleviation of problems of hunger and malnutrition mostly experienced amongst children in developing countries (Aphane et al., 2003).The nutrient values of grain amaranth per 100% edible portion (leaves and tender shoots) has moisture content of 86.9 ml, calorie 36, protein 3.5, fat 0.5 g, total carbohydrates 6.5 g, fiber 1.3 g, potassium 411 mg, iron 3.9 mg, vitamin A (beta carotene) 6100 IU, thiamine (B1) 0.08 mg, riboflavin 0.16 mg, niacin 1.4 mg, ascorbic acid (vitamin C) 80 mg, calcium 267 mg and ash 2.6 g (Ore-Oluwa et al., 1981).The leaves and tender shoots are eaten as pot-herb in sauces or soups, cooked with fish or meat and could be eaten as the main dish.Berkelaar and Alemu (2006) reported that chopped amaranth plants have been used as forage for livestock and that goats fed amaranth forage consistently bore twins.Grain amaranth is one of such important vegetables that could be domesticated and cultivated, but information on its fertility requirements is scanty due to resource-poor conditions encountered in most rural settings of the Northern Guinea and Sudan Savannas where amaranth farmers encounter such problems as decreasing soil fertility and quantity of organic manure required as the source of crop nutrients for optimum crop production (Lucas and Ojeifo, 1985;Adeyemi et al., 1987).Moreover, chemical fertilizers are in short supply and when they are available, their cost is prohibitive for the resource-poor farmers who often utilize Amaranthus in their diet (Olufolaiji et al., 1987).The exclusive use of inorganic nitrogenous fertilizer to improve crop production most of the time has a negative effect on semi-arid tropical soils as this increases soil acidity, hence there is the need to investigate alternative sources of fertilizers for grain amaranth production; such as cattle kraal manure to increase the availability of high quality Amaranthus throughout the wet cropping season at reduced price.According to Schippers (2000), Amaranthus accessions give good yields when high levels of nitrogen are applied and it responds well to organic matter.Thus, the objective of this study is to evaluate the response of grain amaranth to cattle kraal manure method and rate of application on growth and green edible vegetable yield in the Northern Guinea and Sudan Savanna agroecological zones of Nigeria.

Material and Methods
Field experiments were conducted between June and October 2010 wet season at two different locations.(Kowal and Knabe, 1972).The cattle kraal manure used in the two experiments was obtained from the cattle kraal at the cattle ranch, Bagauda (Gidan shanu), opposite Law School, Kano.The manure was analyzed to determine its chemical contents before application as treatment to the trials (Table 1).The experimental cultivar was 'Pure branch', one of the Amaranthus accessions obtained from National Horticultural Research Institute (NIHORT), Bagauda near Kano, Nigeria.Meteorological data of the two locations are shown in Tables 2 and 3.The soils of the experimental sites were analyzed to determine their physical and chemical characteristics (Tables 4 and 5).Seeds of grain amaranth of about 1 kg were mixed with 100 g of Furadan and sown on raised beds 1 x 3 m which were of a mixture of sandy loam soil and properly decomposed cattle kraal manure in ratio 3:1.Soon after, the beds were mulched and watered regularly to ensure good germination.The resultant seedlings were nursed for three weeks before transplanting to the field.The treatments were factorial combinations of five rates (0, 5, 10, 15 and 20 t ha -1 ) and three methods (broadcasting, side banding and spot placement incorporated) of cattle kraal manure application.The experiment was a randomized complete block design (RCBD) with three replications.Each gross plot measured 3 x 4.5 m (13.5 m 2 ) and comprised of 6 ridges per plot and four inner ridges (9 m 2 ) as the net plot for yield assessment while the two outer ridges were used as rows where destructive sampling was carried out for growth assessment.Transplanting of grain amaranth seedlings of height of 12 cm having 3-4 leaves i.e. three weeks after sowing (WAS) was done early in the morning onto moist ridges to reduce transplanting shock.The seedlings were transplanted at 30 cm intra row on 75 cm inter row spacing and replacement of dead seedlings and thinning to one seedling per stand were carried out at 4 weeks after transplanting (WAT).Organic fertilizer in form of cattle kraal manure was applied according to treatment at two weeks after transplanting.The fields were weeded manually using hand hoes at 4, 8 and 12 WAT to keep the plots weed-free.There was no incidence of insect pest and fungal disease problems during the sampling periods.Data collection and sampling for growth and edible vegetable yield characters were done at 4, 8 and 12 WAT.Five plants were randomly selected from the outer rows to determine growth characters such as plant height and stem girth.Ten plants were randomly selected from the net rows in each plot for edible vegetable characters such as number of leaves per plant, leaf area and fresh weight determination.Dry weight was determined after drying in an oven at 70 o C to constant mass for 48 hours.Collected data were analyzed using the general linear model (GLM) procedure of statistical analysis system (SAS) package (SAS Institute Inc., 1999) and significant differences between treatments were compared using standard error of their means.

Results and Discussion
Effect of cattle kraal manure method and rate of application on growth of grain amaranth The result shows that growth parameters of grain amaranth such as plant height and stem girth increased significantly (p > 0.05) with an increase in cattle kraal manure application rate of 10 t ha -1 .At low manure rate (5 t ha -1 ), grain amaranth plants had greater height than those in the untreated control plots, whereas higher rate (10 t ha -1 ) resulted in greater plant heights at 8 and 12 WAT at Samaru (Table 6), which was comparable to results for plant height obtained at 4 and 8 WAT at Kadawa.These responses could be ascribed to increased uptake of nutrients as a result of the availability of large amounts of nutrients in the soil as the amount of manure increased.The method of manure application had no significant influence on plant height.This conforms to the report of Mhlontio et al. (2006) who reported an increase in Amaranthus plant height at higher sheep kraal manure application rate.There were no significant differences among the methods of manure application at all the sampling periods in both locations except at 8 WAT in Kadawa where application by spot placement recorded the largest stem girth when compared to broadcasting and side banding.Manure application rate at 10 t ha -1 resulted in larger stem girth which was statistically at par with all other rates but significantly smaller when compared to the untreated control (Table 7) at Kadawa.However, there was no response to increase in stem girth at Samaru when manure rate was increased to 20 t ha -1 .These results seem to indicate that the application of manure at 10 t ha -1 rate provided sufficient nutrients for maximum stem girth at 4 and 8 WAT growth stages up to 12 WAT and the rest of the nutrients were partitioned towards stem elongation and leaf production.The effect of method and rate of cattle kraal manure application on the number of leaves per plant of grain amaranth is shown in Table 8.The method of cattle kraal manure application did not have any significant influence on the number of leaves per plant of grain amaranth at Samaru at 4 and 8 WAT and at Kadawa at all the sampling periods.The method of application by spot placement recorded significantly higher number of leaves per plant at 12 WAT at Samaru when compared with broadcasting method of application.The difference between broadcasting and side banding was not significant.Rate of manure application had no significant influence on the number of leaves per plant at 4 and 8 WAT in Samaru and at 4 WAT in Kadawa.However, the application of 15 t ha -1 recorded significantly higher number of leaves at 12 WAT when compared with the untreated control which was at par with 5 t ha -1 manure application rate.Further increase in manure rate from 15 to 20 t ha -1 resulted in fewer number of leaves.At 8 WAT in Kadawa, the application of 5 t ha -1 of cattle kraal manure significantly produced larger number of leaves when compared with the control but was at par with all other rates of manure applied, while at 12 WAT, the application of 10 t ha -1 recorded the highest number of leaves that were statistically at par with the application rate of 20, 15 and 5 t ha -1 but higher when compared with the control.Similar findings were reported by Adeyemi et al. (1987) from their study on Amaranthus hybridus, who stated that the number of leaves per plant was not influenced by poultry manure and cutting height at manure rate ranging from 0 to 10 t ha -1 ; but 20 t ha -1 rate produced the number of leaves per plant that was statistically at par with 10 t ha -1 application rate.This was attributed to a slow release of plant nutrients from organic manure at high rate.This also explains why in this trial, cattle kraal manure which was applied to grain amaranth failed to indicate any significant increase between applying manure at 0 t ha -1 up to 20 t ha -1 .Considering that much of the nutrients in cattle kraal manure will be in organic form, therefore, some reasonable length of time would be required for these to be converted to their mineral forms and made available for uptake by the plants in close relation with plant nutrient demand.
Effect of cattle kraal manure method and rate of application on fresh yield of grain amaranth The effect of method and rate of cattle kraal manure application on leaf area (LA) per plant of grain amaranth is shown in Table 9. Methods of cattle kraal manure application had no significant effect on LA.The application of 10 t ha -1 rate of manure at Samaru increased LA of grain amaranth which was significantly higher when compared with the control and the other rates which were statistically at par with 4 WAT and 8 WAT at Samaru and Kadawa respectively.Further increase of manure rate to 20 t ha -1 resulted in reduced LA and was statistically at par with the application rate of 5 and 10 t ha -1 .At 12 WAT, there was no significant difference in the various rates of manure application in Kadawa.These results are in agreement with the findings of Olufolaji et al. (1987) who stated that the lowest manure level of 10 t ha -1 increased leaf area per plant when compared to other higher levels of manure application in Amaranthus.Tindall (1975) reported that Amaranthus requires organic amendment at moderate levels which favours the production of higher leaf area.
Total plant fresh weight increased significantly (p > 0.05) with an increase in cattle kraal manure application rate (Table 10).There were no significant differences among the different methods of manure application on plant fresh weight at all the sampling periods except at 12 WAT at Kadawa where spot placement recorded the highest plant fresh weight when compared to broadcasting and side banding methods of manure application.At low manure application rate (5 t ha -1 ), fresh biomass yields were higher when compared to the untreated control at 4 and 8 WAT at the two experimental locations respectively.Where higher rate of cattle kraal manure (20 t ha -1 ) was applied, fresh biomass yields were comparable to 5, 10 and 15 t ha -1 rates which were significantly higher than the untreated control at all the sampling periods.These responses could be ascribed to increased uptake of nutrients by the crop as a result of high inherent native soil fertility of the experimental locations despite the different rates of manure application.The result here compares well with those reported by Elbehri et al. (1993) for different accessions of Amaranthus, who reported improved forage yield of Amaranthus as a result of nitrogen addition through organic amendment at 10 t ha -1 .Adeyemi et al. (1987) found out that the adequacy of manure decreased the number of days from planting to the first harvest, increased the number of harvests before senescence and therefore recommended that poultry manure improves the rate of regrowth of Amaranthus.The study on cattle kraal manure application for growth and edible green vegetable yield of amaranth, revealed that in the Northern Guinea and Sudan Savanna of agro-ecologies of Nigeria with heavy rainfall that encourages the decomposition of cattle kraal manure, the application of cattle kraal manure rate of 10 t ha -1 to Amaranthus seems to have the highest mean values for all the characters measured such as plant height, stem girth, leaf area, number of leaves, fresh and dry weights due to high inherent native soil fertility of the experimental locations.These results signify that a cattle kraal manure application rate of at least 10 t ha -1 is critical to maximize Amaranthus cruenthus fresh matter yields and it should be recommended to farmers growing Amaranthus in these Nigerian agro-ecological zones.
Effect of cattle kraal manure method and rate of application on dry yield of grain amaranth The effect of cattle kraal manure on dry matter yield increased with increasing manure rate and different methods of application (Table 11).The method of manure application by spot placement recorded significantly higher plant dry matter than broadcasting and side banding which were statistically at par and comparable to method of manure application at 12 WAT except at 4 WAT at Samaru and there was no significant effect on the method of manure application at 4 and 8 WAT at Kadawa except at 12 WAT where method of manure application by spot placement recorded significantly higher plant dry matter when compared to broadcasting and side banding which recorded similar plant dry matter weight.Manure application rate of 5 t ha -1 per treatment, produced greater dry matter that was comparable to 10, 15 and 20 t ha -1 but significantly higher when compared to the untreated control at all the sampling periods in the two locations except at 4 WAT at Kadawa where there was no significant effect on plant dry matter weight at different rates of manure application.These findings suggest that 5 t ha -1 rate of cattle kraal manure would supply sufficient nutrients for grain amaranth used for dry vegetable production especially when the leaves are harvested at a tender age of 8 WAT.It is important to note that at the tender growth stage at which the leaves are harvested as vegetable, fairly moderate cattle kraal manure application rate (5 t ha -1 ) by spot placement gave better results which were comparable to the other higher rates due to availability of adequate moisture in the soil at this growth stage.This could be due to differences in water uptake by the crops at these sampling periods.From the differences in plant fresh and dry weights responses to the two different cattle kraal manure rates, the results point to the fact that the crops in 5 t ha -1 manure application plots took up more moisture than 10 tha -1 manure rate.Aside from the dry matter yield, the green fresh edible vegetable is mostly desired and a cattle kraal manure application of 10 t ha -1 would appear more logical rate at which to grow Amaranthus successfully in these Nigerian agro-ecological zones.

Conclusion
The study on cattle kraal manure application on growth and green edible vegetable yield of amaranth, revealed that in the Northern Guinea and Sudan Savanna of agro-ecological zones of Nigeria with heavy unimodal rainfall that encourages the decomposition of animal manures, the application of cattle kraal manure rate of 10 t ha -1 to Amaranthus seems to have the highest mean values for all the indices measured such as plant height, stem girth, number of leaves, leaf area, fresh and dry weights.This study showed that to obtain maximum green edible vegetable yield per plant, amaranth growers are expected to apply cattle kraal manure at 10 t ha -1 .Tindall (1975) from his trial reported that Amaranthus requires soils with high organic matter content which favours the production of fresh vegetables.Thus, 10 t ha -1 should be recommended to farmers growing Amaranthus in the Northern Guinea and Sudan Savanna agroecological zones of Nigeria.
The first location was the Horticultural Research Garden of the Institute for Agricultural Research, Ahmadu Bello University, Samaru, Zaria (11 o 11'N, 7 o 38'E and 686 m above sea level) which is located in the Northern Guinea Savanna ecological zone of Nigeria.The second experiment was conducted at the Research Farm of the Irrigation Research Sub-Station also of the Institute for Agricultural Research, Ahmadu Bello University, Kadawa (11 o 39'N, 80 o 27'E and 500 m above sea level) in the Sudan Savanna ecological zone of Nigeria

Table 1 .
Chemical contents of the cattle kraal manure used in the two experiments.

Table 4 .
Pre-cropping physical and chemical characteristics of soil (0-15 and 15-30 cm) taken from the experimental site at IAR Samaru in the Northern Guinea Savanna, Nigeria.

Table 5 .
Pre-cropping physical and chemical characteristics of soil (0-15 and 15-30 cm) taken from the experimental site at Irrigation Research Station (IRS) Kadawa in the Sudan Savanna, Nigeria.

Table 6 .
Effect of cattle kraal manure method and rate of application on plant height (cm) of grain amaranth at Samaru and Kadawa.

Table 7 .
Effect of cattle kraal manure method and rate of application on stem girth of grain amaranth at Samaru and Kadawa.

Table 8 .
Effect of cattle kraal manure method and rate of application on the number of leaves per plant of grain amaranth at Samaru and Kadawa.

Table 9 .
Effect of cattle kraal manure method and rate of application on leaf area per plant (cm 2 ) of grain amaranth at Samaru and Kadawa.

Table 10 .
Effect of cattle kraal manure method and rate of application on plant fresh weight (gm) of grain amaranth at Samaru and Kadawa.

Table 11 .
Effect of cattle kraal manure method and rate of application on plant dry weight (gm) of grain amaranth at Samaru and Kadawa.