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Efforts to enhance maize stover utilization for smallholder livestock producers in Malawi

B H Dzowela
Ministry of Agriculture, Chitedze Research Station, P.O. Box 158, Lilongwe


Abstract
Introduction
Materials and methods
Results and discussion
Conclusion
References

Abstract

An attempt to boost the smallholder livestock farmer feed resourses qualitatively and quantitatively through the integration of improved forages in maize crop production systems is discussed. Where the testing of different forage systems undersown in maize was done on smallholder dairy farms, the Rhodes grass-silver-leaf desmodium appeared to make a better contribution to the overall forage production.

On station, the time of sowing/undersowing the forage legumes in a maize crop had no effect on all components of yield except forage legume yield which was depressed by delayed planting. Significant differences were obtained between the different forage systems and maize stripping intensities. There was a tendency for the climbing forage legume species to enhance the crude protein value of the maize stover component.

Introduction

Recent estimates by Mkamanga (1986) on national cereal grain production in Malawi puts the hectarage devoted to maize production at 1,145,100 ha with a total grain production of 1,355,200 tonnes. This production figure is 4.6 times the documented purchases of this crop by the Agricultural Development and Marketing Corporation (ADMARC) (Dzowela 1985). The reason for this discrepancy is that the major portion of the national production is used directly for consumption by the farm families themselves, maize being the stable cereal crop.

Alongside this large cereal grain production, there is an estimated 1.5 million tonnes of maize stover. This maize stover is a readily available feed resource to smallholder livestock producers which is utilized by livestock in situ, after the maize ears are removed, or cut and stall-fed. Maize stover per se as a feedstuff for livestock is inferior when compared to other locally available feed materials (Table 1).

The most limiting factor to animal performance fed on maize stover appears to be that of dietary protein. Protein supplementation alleviates the deficiency but a majority of protein supplements may be too expensive for the smallholder producers to afford on a regular basis. The most logical way of getting round this problem would be to incorporate tropical forages in the maize cropping systems (Dzowela, 1985). After the maize ears have been removed, the forage legume component, especially the climbing types could make an important contribution to maintaining adequate protein levels in the maize stover-based diets. The legume component could act as a source of protein above the 7% threshold and also in promoting increased intake of the associated maize stover.

Table 1. Comparison of maize stover with various other feed stuffs available on smallholder dairy farms in Malawi.

Feedstuff

No. of Samples

%CP

Range

%CF

Madeya (Maize bran)

4

10.7

(10.6 - 10.9)

5.5

Groundnut haulms

5

11.2

(10.9 - 11.6)

39.9

Maize stover with leaves

3

3.2

(2.8 - 4.9)

30.6

Rhodes grass hay

9

4.5

(3.5 - 5.2)

36.2

Maize silage

11

6.6

(5.2 - 9.1)

36.2

Dzowela (1985) outlined some of the chemical-based technologies for increasing the nutrient availability from maize stover. These methods include ammonia treatment and soaking in a solution of sodium hydroxide. This paper focusses on the work currently undertaken by the Pastures Commodity Research Team of the Ministry of Agriculture in attempt to integrate improved forages with maize cropping systems in Malawi.

Materials and methods

Smallholder based work

Using the adaptive on-farm research approach, some smallholder dairy farmers participated in an integrated maize crop-forage improvement programme in the Kasungu Agricultural Development Division. The pasture intervention was based on four systems, namely:

a. Pure Rhodes grass
b. Rhodes grass in association with silverleaf desmodium (Desmodium uncinatum)
c. Rhodes grass in association with Common Centro (Centrosema pubescens)
d. Rhodes grass in association with a "Shotgun" mixture involving Silverleaf desmodium, Common Centrosema, Neonotonia wightii and Joint vetch (Aeschynomene americanum).

All these pasture systems were undersown to maize after the first weeding operation before the maize crop was knee high. A similar approach was adopted in the 1984/85 season, in which the maize crop-improved pasture integration was done on three smallholder farms as a pre-fallow exercise. During the 1985/86 season a quantification of the forage production in both the newly established four pasture systems and those established in the 1984/85 season was done.

Station Based Work

This work was undertaken for a second season at Chitedze Agricultural Research Station during the 1985/86 season. The object was to generate simple technologies geared towards the integration of forage in cereal grain production of smallholder dairy producers. Four pasture systems were tested, namely;

a. Maize - common Centrosema (C. pubescens)
b. Maize - Neonotonia wightii
c. Maize - Centrosema pascuorum
d. Maize - Silverleaf desmodium.

These four forage legume systems were either sown at the same time the maize (MH12) was planted in November, 1985 or undersown after the first weeding of the maize crop when the maize plants were 30 cm high. In both cases the forage legumes were drilled on top of the ridge in between the maize planting stations which were 0.90m apart.

Based upon similar work in the previous year (Dzowela 1985), the maize leaves below the maize cob were stripped at weekly intervals from the silking/anthesis physiological development stage for seven weeks. The stripping of the lower maize leaves which serve no useful purpose in maize grain filling (Loomis 1935; Stickler and Pauli 1961; Hoyt and Bradfield 1962; Chaudhry 1969; Tanaka and Yamaguchi 1972; Soza et al 1975), could provide a cheap feed resource of high nutritive value to dairy animals on smallholder farms (Dzowela 1985). In the current study, results of this work are presented.

Results and discussion

On-farm Research

A quantification of the pasture systems sown the previous (1984/85) season revealed that the silverleaf desmodium - Rhodes grass system produced the largest amounts of forage dry matter (Table 2); being 38 per cent more than the pure Rhodes grass pasture system. The Rhodes-Centrosema system resulted in 11 per cent more forage than the pure Rhodes system. The silverleaf botanically accounted for more than 40 per cent of the sward, based on visual estimates, whereas Centrosema was less than 20 per cent.

Table 2. Second year's forage DM yields from the three pasture systems

Pasture system

DM yields in kg/ha

Pure Rhodes system

3805

Rhodes + Silverleaf

6110

Rhodes + Common Centro

4213


Mean

4709


SE

±660*

For the pasture systems established in the 1985/86 season the forage DM yield data are shown in Table 3.

Table 3. Forage DM yields of the pasture intervention systems in 1985/86 season

Pasture Systems

Pasture Components

Forage DM yield in kg/ha

Maize-Rhodes


Maize stover

3834

Rhodes grass

1430

Maize-Rhodes with silverleaf



Maize stover

4440

Rhodes grass

1016

Silverleaf

433

Maize-Rhodes with shotgun mixture



Maize stover

3808

Rhodes grass

1149

Legume mixture

152

Maize-Rhodes with Centrosema



Maize stover

2903

Rhodes grass

2910

Centrosema

123

SE (Pasture systems)



Stover

±380*

Rhodes grass

±242**

Legumes

±225*

The Rhodes grass - Centrosema pasture system was the best intervention from the point of view of total forage production even though the very low maize stover yields in this system was below average. The system contributed 104 per cent more forage over and above the maize stover, but of the forage production only 4 per cent was contributed by the Centrosema component. The Rhodes-silverleaf system which produced comparable forage yields to the pure Rhodes system had a 30 per cent silverleaf contribution to the overall forage production of the pasture intervention over and above maize stover. The Rhodes-shotgun mixture system on the other hand, gave lower forage yields than the pure Rhodes intervention; the legume component in this system contributed 12 per cent to the total forage production over maize stover.

All systems were able to contribute significantly towards feed resources of the smallholder livestock producers over and above the maize stover production. The forage production from the pasture intervention system had a higher crude protein content of well above the minimum recommended value of 7.0 per cent, whereas the maize stover alone is less than 5.0 per cent in crude protein content (Dzowela 1985).

Station Research

Maize grain yield was not affected by the forage legume sowing/undersowing time and both the forage legume system and maize stripping intensity treatments did not have any effect on grain yield either. The fact that there were no significant grain yield reduction as a result of maize leaf stripping confirms what is already known about the physiology of the maize plant (Loomis 1935; Stickler and Pauli 1961; Hoyt and Bradfield 1962; Chaudhry 1969; Tanaka and Yamaguchi 1972; Soza et al. 1975). Maize stover yields were also not affected by legume sowing/undersowing time, forage legume systems or maize leaf stripping intensity (Table 4). With respect to forage dry matter yields as affected by the stripping of the different maize leaves, there was no interaction with time of undersowing. But the forage systems resulted in significant differences in the amounts of stripped leaf forage DM produced. The least amount came from the Neonotonia forage system (P<0.05) as shown in Table 5. There was a significant progressive increase in the amount of forage DM produced the more the plant leaves were stripped (P<0.01).

The total forage yields from all the leaves below the cob indicate the potential of using such a feed resource for ruminant feeding which is otherwise a useless component in maize grain filling processes. Use of these leaves below the cob for forage purposes is a practice in Guatemala, Egypt and Kenya (Soza 1975; Abate et al, 1985). It is a feed resource of high quality with a crude protein content of no less than 12 per cent (Dzowela 1985). Delay in sowing/undersowing of the forage legume from the time of planting maize to after the first maize weeding operation resulted in a significant reduction in forage yields from the pasture systems (P<0.01) as shown in Table 6. This reduction is a reflection of the smothering effect of the maize canopy on the early development of the forage legumes.

The forage legume component contribution to overall forage production in the different interventions was not affected by time of sowing/undersowing. The least amount of forage was contributed by Neonotonia which for two years now has indicated to be slow in establishment and hence most smothered in association with a maize crop (Dzowela 1985). The largest amount of forage came from the Pascuorum followed by the Silverleaf system (Table 7). There was a tendency for the legume forage DM to increase with maize leaf stripping intensity as a manifestation of improving light relationship underneath the maize canopy.

Table 4. Maize grain and stover yields from the four forage legume systems and maize leaf stripping intensities.

Pasture System

 

Maize leaf stripping

1

2

3

4

5

6

7

Means

Maize-Common Centrosema:

Grain

6415

7760

7857

7387

6761

6257

6027

6922

Stover

8504

9309

9230

8633

7771

7955

7711

8445

Maize-Neonotonia:

Grain

5992

5503

6490

5284

6566

6340

6868

6149

Stover

8188

7951

9359

8235

8463

7481

8005

8249

Maize-Pascuorun Centrosema:

Grain

6424

5206

7117

5593

5832

6581

4818

5939

Stover

8649

6888

8116

7847

8463

8879

7279

8017

Maize-Silverleaf

Grain

6680

7370

6553

7416

6882

6689

6125

6816

Stover

7150

8952

7847

8163

8561

8232

7109

8002

Means:

Grain

6378

6460

7004

6420

6510

6465

5960


Stover

8123

8275

8638

8220

8314

8137

7526


S.E. Pasture


Systems:

Grain

±202NS

Stover

±288NS

S.E. Stripping


Intensity:

Grain

±355NS

Stover

±342NS

Table 5. Stripped maize leaves and forage DM yields from the different Pasture systems and position of the stripped leaf below the cob

Pasture System

Leaf Position

Total Means

Forage kg/ha

1

2

3

4

5

6

7

Common Centrosema

243

226

317

477

515

481

544

400

2803

Neonotonia

162

223

326

384

523

471

512

372

2601

Pusecuorum Centrosema

178

232

351

497

514

569

533

411

2876

Silverleaf

178

199

306

437

488

534

522

381

2664

Means

190

220

325

449

510

514

528



S.E. of Pasture systems means

±8.2*

S.E. of leaf position means

±173***

Table 6. Forage legume DM yield in kg/ha in response to time of sowing per undersowing

Forage System

Stripping Intensity

Means

1

2

3

4

5

6

7

Maize-Common Centrosema

T1 324

448

681

377

253

200

380

353

T2 146

274

271

207

221

163

188

210

Maize-Neonotonia

T1 23

211

98

59

130

86

71

97

T2 23

41

22

45

46

67

32

39

Maize-Pascuorum

T1 738

1044

739

576

740

656

866

764

T2 222

364

392

350

497

340

475

377

Maize-Silverleaf

T1 801

478

563

653

522

719

318

579

T2 248

280

363

224

465

358

402

334

Means

T1 472

545

518

417

535

428

364

468

T2 159

240

262

207

308

232

274

240

S.E. (T. Means)

±85***

Table 7. Forage DM Yield in kg/ha of the legume components in the different systems

Forage System

Maize leaf stripping intensity



1

2

3

4

5

6

7

Means

Maize-Centrosema

235

260

476

293

188

207

194

269

Maize-Neonotonia

22

125

60

52

88

76

61

68

Maize-Pascuorum

480

704

560

463

619

498

670

571

Maize-Silverleaf

525

379

463

439

494

538

360

457

Means

315

392

390

312

470

330

319


S.E. (Pasture systems)

±61 **

S.E. (Stripping intensity)

±42 ***

Table 8. Crude protein percentages (on DM basis) of the maize stover from the four pasture systems

Forage System

Maize leaf stripping intensity

Means

1

2

3

4

5

6

7

Maize-Centrosema

7.07

8.24

7.16

6.34

6.42

6.88

5.99

6.91

Maize-Neonotonia

6.97

7.88

6.88

5.92

6.81

5.54

5.04

6.43

Maize-Pascuorum Centrosema

6.46

7.94

6.91

5.94

4.69

4.88

4.13

5.85

Maize-Silverleaf

5.25

5.48

4.94

4.00

4.92

4.50

3.71

4.69

Means

6.44

7.46

6.47

5.55

5.71

5.45

4.72


S.E. Pasture System Means

±0.202 **

S.E. Leaf Stripping Intensity Means

±0.351 ***

Qualitatively, maize stover crude protein content was not appreciably affected by the forage legume sowing/undersowing time. The inclusion of the climbing forage legumes (Centrosema Neonotonia and Pascuorum) resulted in a maize/legume and stover product higher in crude protein content than the silverleaf-based stover (P<0.01) (Table 8). The climbing forage legumes were intact on to the stover at the time of harvesting the stover and contributed to the high CP contents. The silverleaf desmodium, on the other hand being determinate in its growth habit was not attached to the maize stover at the time of cutting.

There was a tendency for the maize stover crude protein content to decrease with the maize stripping intensity (Table 6). Maize stripping as such is a physical removal of the component of the maize plant that is more nutritive than the stem. However, the fact that the stripped leaf material when stripped before senescence is a product of high quality (Dzowela, 1985) which could be fed to animals fresh or dried, may more than compensate for the reduction in the CP content of stover per se.

Conclusion

These sets of data appear to demonstrate the potential for integrating improved forage technology in maize cropping systems of smallholder livestock producers. It helps to improve the feed resources of such smallholder livestock producers quantitively and qualitatively. Once adopted they could have an enhancing effect on the utilization of crop by-products such as maize stover and some of the otherwise wasted products from the maize plant.

The potential of climbing forage legume species ought to be explored further, especially those that stay green longer after the maize crop has dried up.

References

Abate A., Kayongo-Male H. and Wanyoike M. 1985. Fodder for high potential areas of Kenya. To be published in the proceedings of the Pasture Network for Eastern and Southern Africa Workshop on "Animal Feed Resources for Small-scale Live stock Producers", November 11-15, Nairobi, Kenya.

Boza R.F. Violic A.D. and Claure V. 1975. Maize forage defoliation. A paper presented at the XXI PCCMCA Meeting, El Salvador.

Chaudry A.R. 1969. Effect of defoliation treatments on yield in maize. Proceedings of the Sixth Inter-Asian Corn Improvement Workshop, India, p.37-39.

Dzowela B.H. 1985. Maize stover improvement with Legume forages. To be published in the proceedings of the Pasture Network for Eastern and Southern Africa Workshop on "Animal Feed Resources for Small-scale Livestock Producers", November 11-15, Nairobi, Kenya.

Hoyt P. and Bradfield R. 1962. Effect of varying leaf area by partial defoliation treatments applied at various stages of development. Agronomy Journal 54: 523-525.

Loomis W.E. 1933. The translation of Carbohydrates in maize. Journal of Science 9: 509-520.

Mkamanga G.Y. 1986. Cereal Crops Research Achievements and Production Problems in Malawi. A paper presented at the Annual Research Extension Workshop, 17-21 March, Mangochi, Malawi.

Stickler F.C. and Pauli A.W. 1961. Leaf removal in grain siorghum. 1. Effect of certain defoliation treatments on yield and components of yield. Agronomy Journal 53: 99-102.

Tanaka A. and Yamaguchi J. 1972. Dry matter production, yield components and grain yield of the maize plant. Journal of the Faculty of Agriculture, Hokkaido University.


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