Rice and maize productivity under smallholder conservation agriculture practices in Lower Moshi Irrigation Scheme, Tanzania

Transcription

1 Rice and maize productivity under smallholder conservation agriculture practices in Lower Moshi Irrigation Scheme, Tanzania Didas N. Kimaro, Patrick Bell, Nyambilila Amuri, Oforo D. Kimaro, Firmat Banzi and Rattan Lal Paper presented to the iagri Collaborative Research Phase I and Phase II Workshop Presentation of Research Results on April 2016 in Morogoro, Tanzania DNK iagri 1

2 Introduction Increasing rice demand Changing preferences Decreasing water supply (major problem in Tanzania) Declining soil fertility Climate change Increased temperatures Decreased precipitation Declining crop yields (rice and maize)

3 Lower Moshi Irrigation Scheme, Tanzania is dominantly under irrigated rice farming for about 25 years without appropriate management for improved productivity Constraints: High rates of N fertilizer application (>200 kgn/ha) No consideration of other types of fertilizers like P & K Recently farmers are experiencing low yields (less than 4 Mg/ha of rice from Mg/ha when the scheme was started) DNK iagri 3

4 Objectives Therefore, a study was carried out to evaluate the impact of CA practices on rice and maize; develop technologies for adoption by smallholder famers in the context of climate change and hence for improved smallholder productivity

5 Materials and methods Location of the study sites The lower Moshi irrigation scheme located in semiarid plains, Moshi district, Tanzania at the foot of Mount Kilimanjaro Geographically the area is located at and Eastings and and Northings, Zone 37 UTM coordinate system Rainfall: less than 800 mm/year Rau River: is the main source of irrigation water in the area Land use: dominantly irrigated farming, rainfed farming and light grazing DNK iagri 5

6 Methods: Three experiments Experiment 1: lablab maize rotation: Upland rainfed with supplemental irrigation maize Short rainy Season: Planting Lablab to generate biomass for Incorporation into the soil to improve soil fertility; Incorporating Lablab biomass into the soil followed by maize cultivation in the long rainy season Planting Lablab to generate biomass for Incorporation into the soil to improve soil fertility (spacing 25 cm by 25 cm) Incorporating Lablab biomass into the soil for soil fertility improvement DNK iagri 6

7 Maize farming in March May 2015 (spacing 35cm by 90 cm) Maize cultivation in the long rainy season after Lablab biomass Incorporated into the soil Treatments: RCBD with CTLU = Conventional tillage (LABLAB INCOPORATED) + UREA RTLF = Reduced tillage (ripping) (LABLAB INCOPORATED) + FYM RTLN = Reduced tillage (ripping) (LABLAB INCOPORATED) + NPK CTLN = Conventional tillage (LABLAB INCOPORATED) + NPK DNK iagri 7

8 Experiment 2: Paddy maize rotation farming system: Rice (SARO variety) planted in Jan 2014 and harvested in May/June 2014; followed by seasonal fallow June 2014/Feb 2015 after crop residues of the previous season incorporated into the soil. This was followed by seasonal maize farming in March May 2015 and harvested in July 2015 Incorporating rice crop residues into the soil for soil fertility improvement after rice harvest DNK iagri 8

9 Paddy maize rotation farming system with System of Rice Intensification (SRI) Treatments: RCBD with CU = Conventional kg N/ha as Urea only SU = SRI kg N/ha as Urea only SN = SRI + NPK (120 kg N/ha, 20 kg P/ha and 25 kgk/ha) CN = Conventional + NPK (120 kg N/ha, 20 kg P/ha and 25 kgk/ha)

10 The System of Rice Intensification (SRI) : Carbon Management and Sequestration Center Transplant seedlings early 15 days after sowing Reduce plant density 25 cm X 25 cm Improve soil conditions retain residue + NPK Reduce and control water 4 cm depth

11 Maize farming in March May 2015 (spacing 35cm by 90 cm) Maize cultivation in the long rainy season after fallow with rice crop residues incorporated Incorporated into the soil Treatments: RCBD with CTRU = Conventional tillage (RICE CROP RESIDUES INCORPORATED) + Urea RTRF = Reduced tillage (ripping) (RICE CROP RESIDUES INCORPORATED) + FYM RTRN = Reduced tillage (ripping) (RICE CROP RESIDUES INCORPORATED) +NPK CTRN = Conventional tillage (RICE CROP RESIDUES INCORPORATED) + NPK DNK iagri 11

12 Experiment 3: Continuous irrigated paddy farming system: Three seasons; Rice (SARO variety) planted in Jan 2014 and harvested in May/June 2014; season 2 in July to Nov 2014; and season 3 in Jan May/June 2015 Conventional and System of Rice Intensification (SRI) Treatments: RCBD with CU = Conventional kg N/ha as Urea only SU = SRI kg N/ha as Urea only SN = SRI + NPK (120 kg N/ha, 20 kg P/ha and 25 kgk/ha) CN = Conventional + NPK (120 kg N/ha, 20 kg P/ha and 25 kgk/ha) DNK iagri 12

13 Data collected: Biomass Tillers Grain yield

14 Composition of green lablab biomass and effect of lablab incorporation on ph, Total N, extractable P, Ca, Mg, K, and Na from 0 20 cm compared to baseline after one growing season Sample No Biomass (Mg/ha) TN (%) TP (%) TK (%) ph (H 2 O) ph (CaCl 2 ) Total N (%) P (mg kg 1 ) Ca Mg K Na cmol/kg Baseline 6.49 (0.1) a ± 5.82 (0.04) a 0.07 (0.01) a 56.8 (1.0) a 6.2 (0.2) a 2.9 (0.1) a 1.7 (0.2) a 0.2 (0.02) a After lablab season Results 6.71(0.2) a 6.15 (0.2) a 0.09 (0.02) a (11.8) b 24.5 (4.6) b 3.9 (0.5) a 2.2 (0.2) b 0.4 (0.02) b Means followed by standard deviations in parenthesis. ± Means followed by the same letter indicate no significant difference within the same column (p<0.05) DNK iagri 14

15 Effect of lablab maize rotation, tillage methods and nutrient management on maize grain yield Treatme nt Baseline CTLU RTLF RTLN CTLN MGyd (Mg/ha) a 4.000a 3.933a 3.467a LSD 5% F.PR= Means followed by the same letter(s) do not differ significantly at < 0.05; CTLU = Conventional tillage (LABLAB INCOPORATED) + UREA; RTLF = Reduced tillage ripping (LABLAB INCOPORATED) + farmyard manure (FYM); RTLN = Reduced tillage ripping (LABLAB INCOPORATED) + NPK; CTLN = Conventional tillage (LABLAB INCOPORATED) + NPK; DNK iagri 15

16 Effect of System of Rice Intensification (SRI) maize rotation and nutrient management on yields of rice and maize Treatmen t Baseline CU SU SN CN Rice yield (Mg/ha) ab 4.33ab 6.08a 6.17a LSD 5% F.PR= Treatme nt Baseline CTRU RTRF RTRN CTRN Maize yield (Mg/ha) a 5.000ab 4.133b 3.800b LSD 5% F.PR= Increased yields of rice for SRI over conventional flooding practice and interestingly elevated maize yields in plots coming out of the SRI based system when compared to normal farmer practices with less input DNK iagri 16

17 SRI Conventional flooding practice Effect of SRI and Multinutrients management (two levels of nutrients (NPK) and single nutrient (Urea) application) on paddy tillering, above ground biomass and root growth DNK iagri 17

18 Influence of water regime and nutrient management on tillering across different rice growth stages Treatments T2 T3 T4 SRI + Urea a ab ab Conventional + Urea b c c SRI + NPK a a a Conventional + NPK b bc bc LSD 5% =5.597 LSD 5% =4.455 LSD 5% = Means followed by the same letter or letters do not differ significantly. T2=Number of tillers at vegetative stage; T3=Number of tillers at booting stage; T4=Number of tillers at full booting stage, SRI = System Rice Intensification, NPK = Nitrogen phosphorus potassium ( ) fertilizer DNK iagri 18

19 Influence of water regime and nutrient management in rice above ground biomass Treatments Above ground biomass (g/hill) SRI + Urea a Conventional + Urea 55.15c SRI + NPK 96.75ab Conventional + NPK 63.19c LSD 5% = 25.72; (P<0,05)=0.036 Means followed by the same letter(s) do not differ significantly at < 0.05 DNK iagri 19

20 Rice grain yield for each treatment within each growing season (Error bars represent standard deviation) For all treatments and all seasons, no significant difference in yields. However, SRI achieved this feat with about a third less seeds and 40 50% less water DNK iagri 20

21 The findings indicated that SRI might play a significant role in helping smallholder rice farmers to adapt to future climate change through reduction in water input The highest yields obtained from the SRI system with NPK fertilisation for the captured seasons in the study area indicate that it is possible to increase yields while reducing the irrigation water requirements by almost 50% 03/05/

22 Conclusions and recommendations The study has clearly demonstrated that it is possible to increase productivity of maize cropping system by incorporating lablab into the soil in the form of high quality biomass that increases fertility status of the soil while at the same time increasing maize production. DNK iagri 22

23 Conclusions cont. Noted that yields were higher for SRI over conventional practice and interestingly maize yields were relatively elevated in plots coming out of the SRI based system when compared to normal farmer practices with less input. The results have demonstrated significant water use efficiency for rice production under SRI. DNK iagri 23

24 Conclusions cont. SRI might play a significant role in helping smallholder rice farmers to adapt to future climate change through reduction in water input The SRI also has caused remarkable root growth of rice. However, it is unclear why there is such strong crop responses, particularly on crop that was managed with standard cropping practices. DNK iagri 24

25 Conclusions cont. There a number of research questions that could not be answered about SRI relative to soil quality and nutrient dynamics. Specifically, soil physical and microbiological investigations need to be pursued to determine the relationship of these factors for SRI to root growth, tillering and yield of rice and maize. DNK iagri 25

26 Thank you for listening and God Bless You Acknowledgement The authors are grateful to USAID through the Innovative Agriculture Research Initiative (iagri) project for funding this work and facilitation to attend this workshop. We also thank the extension staff & farmers of the Lower Moshi Irrigation Scheme, Tanzania. DNK iagri 26