By

Dhliwayo D.1, Chikwari E. 1, Mhaka L.1, I Nyagumbo2 and Lee Heng3.

1 Chemistry & Soil Research Institute, Dept. of Research and Specialist Services, Harare, Zimbabwe

2 CIMMYT, Zimbabwe 3 IAEA, Vienna IAEADR&SS

Impacts of climate change affecting smallholder farmer in semi arid Zimbabwe includeI. Erratic rainfall pattern II. Mid-season dry spell

This is further worsened by I. Poor soil fertility II. Resource constrained.

Poor yield<1t/ha

Several break through were made on Water conservation technologies Soil fertility management systems butSmallholder agricultural production

remained Gaps still exist on the interactive effect of

these technologies on Soil moisture storage total plant biomass and grain yield

To evaluate the effects of post planting tied ridging conservation farming basins, rip and pot holing integrated to organic and inorganic fertility management regimes on soil profile moisture storage and plant nutrient uptake (nitrogen and phosphorus)

To assess the effects of integrating post planting tied ridging (PTR), rip and pot holing (RPH) and conservation farming basins (CA) with organic and inorganic fertility management regimes on maize and soya bean yields

To determine the labour productivity and influence of resource endowment on farmers’ capacity to scale out water and soil nutrient management technologies stated in the objective 1.

Kadoma

Domboshawa

Kadoma (NRIII – 650 – 800 mm year-1) Soil type Sand loam soil Domboshawa Training centre (NRII 800-1000mm year-1

Soil type sand loam soil

Project location

Experimental lay out Split plot experimental design with4 main tillage treatments replicated 3 times

Conventional mouldboard

tillage

Conservation farming

basins (CA)

Rip and pot holing (RP)

Post planting tied

ridging

Sub-treatments (randomly superimposed on the main tillage treatments manure ( M) at 5 t ha-1

Basal fertilizer (compound D) (F) at 300 kg ha-1

Combination of the above at the same rates (MF)Control (C) – no fertility amendmentsTop dressing was split applied at 300kg per ha in

the maize trial plots.Weed control was done manually using a hoe in

the first season chemical weed control was used in the second

season

To answer objectives 1 &2Gravimetric water content was determined

at depth 0-15cm, 15-30 cm and 30-45cm from each subplots at 3 week interval.

Sampling for Bulk density was done at the end of the season.

Yield and biomass was determined from check plot measuring 5m x 4 rows

Above ground plant material was sample at 14 weeks after germination from 3 sites for total plant nitrogen and phosphorus uptake.

Foliar analysis for plant nitrogen and phosphorus was carried out using (micro – kjeldahal (Anderson and Ingram ,1993)

Data capturing in progress.

4 additional plots measuring 100 x 20 were established for labour productivity on 3 sites in Kadoma.

Tied ridging, Conservation farming basins, Conventional mouldboard ploughing, Rip and pot holing were implemented on the 4 plots

Labour hours for each technology were measured through out the season.

Grain and biomass yield was determined from 6 net plots measuring 5m x 2 rows.

A combined analysis of variance across sites derived from split plot arrangements on each farmer/site was used to analyse treatment effects on the various parameters using GENSTAT statistical package.

Socio-economic data generated will be analysed using SPSS to assess resources endowment classes and their effect of scaling out on the technologies under study.

Figure 1a: Effects of integrating soil moisture and nutrient management techniques on soil profile moisture storage, Domboshawa (Lsd - 16.96) (2009-2010 ).

Note: Con – conventional tillage, CA – conservation farming basins, RP – rip and pot holing, TR – post planting tied ridging

Figure 1b: Effects of integrating soil moisture and nutrient management techniques on soil profile moisture storage, Kadoma (Lsd – 13.98) (2009-2010 ).

Figure 2a. Maize grain yield from integrated tillage systems with soil fertility management options (Kadoma – 20009/10) ( l.s.d = 0.8485)

Figure 2b. soya bean grain yield from integrated tillage systems with soil fertility management options (Kadoma – 20009/10) l.s.d = 0.3607 )

Note: CT – conventional tillage, CA – conservation farming basins, RP – rip and pot holing, TR – post planting tied ridging

Fig. 3. Effects of the integrating water and nutrient management techniques . Domboshawa site ( 2009 – 2010 season). Note: CT- conventional, CFB conservational agriculture, TR- Post planting tied ridging.

Figure 4a. Maize grain yield from integrated tillage systems with soil fertility management options (Kadoma – 2010/11) ( l.s.d = 1.166 )

Figure 4b. Soya bean grain yield from integrated tillage systems with soil fertility management options (Kadoma – 2010/11) ( l.s.d = 0.3431 )

Note: CT – conventional tillage, CA – conservation farming basins, RP – rip and pot holing, TR – post planting tied ridging

Soil profile water storage in Kadoma Although manure sub-treatment had slightly higher soil

profile moisture storage, generally there was no sighficants difference due to fertility amendments. The sight increase in water content in manure sub-treatment might be attributed to the increased CEC as a result extra organic matter from manure.

Generally there was no interaction between tillage system and fertility management options on the water holding capacity of the soil

Although Conservation farming basins showed slightly higher soil profile moisture storage relatively conservation tillage, there was no significant difference between the two treatments.

This lack of significant might be due the speedy disappearance of crop residues in the CFB which were supposed to have a mulching effect, resulting in increased evapo-transpiration.

Soil water profile moisture storage were comparatively the same in CFB and RP (Rip and potholing) probably as a result of the pot holing in RP treatment having the same influence on water infiltration as the mulching in CFB.

Tied ridging significantly increased soil profile moisture storage when compared to conventional mouldbould tillage across all fertility treatments.

This resulted from small ponds created by the tied ridging which traps runoff increasing infiltration as opposite CT where water runoff restriction is minimum.

I would like to acknowledge the following for making the project a success

1.Department of Research and specialist services

2.AGRITEX Kadoma, 3.CIMMYT, and 4. IAEA