Conservation Agriculture: Quantitative research support to the
Smallholder Farmer Innovation Programme in KZN: 2019-2021
Kruger E, Dlamini M, Mathebula T, Madondo T,MalingaM,NMdletshe and Smith H.
Interns: Buthelezi L and Mzobe N.
The CA-Adaptive research SFIP
Aims:
TopromotetheuseofCAto
ØIncrease farming production and
profitability,
ØImprove the natural resource status
and quality allowing sustained crop
production / intensification and
ØProvide science-based evidence for
the impact of CA on the smallholder
farming system.
Aims and Objectives
Objectives:
ØOBJECTIVE 1: To assess the impact of a range
of CA practices on water, soil and productivity
indicators, within a smallholder farmer level
experimentation process
ØOBECTIVE 2: To use results from qualitative
and quantitative analysis to outline best bet
options for the smallholder CA farming
systems and to provide recommendations for
improvement of the system.
The smallholder farming system
Smallholder
farming
system
Dryland cropping of
staples on small
patches of available
land (0,1-1ha)
Extensive
grazing of
livestock on
stover and veld
Intensive
homestead food
production;
vegetables, fruit,
small livestock
Feed
biomass
mulch
Manure
mulch
Fodder
manure
stover
Cover
crops,
non
staples
OM and
soil
fertility
Little to no
soil cover
Experimentation protocols chosen by the participants (researchers
and farmers) are as follows:
45CMTs
1. 10x10 blocks (1000m2): A 10-plot layout of 100m2plots, for
multiple cropping options (maize, legumes and cover crops), which is rotated on
an annual basis.
2. Strip cropping (1000m2 ): Planting of 4m wide strips on contour, to
provide for soil and water conservation concerns and ease of implementation in
larger fields, for multiple cropping options (maize, legumes and cover crops),
which is rotated on an annual basis.
3. Short season maize: Planting of early maturing maize (white-
PAN5A172andyellow-PAN5A190)alongsidethenormalvarietiestotest
adaptability to climate variation, either in block or strip cropping trials.
4. Fodder production:Planting of annual and perennial livestock
fodder species (Teff, Tall fescue, Lespedeza), for both in situ grazing and baling,
either in block or strip cropping trials.
5. Cover crop seed production and poultry feed: 250m2fenced
plots are planted to cover crop species (sunflower, Sun hemp, Fodder Sorghum,
Dolichos, turnips) with the specific intention of keeping seed, for sharing and sale
of cover crop seed to local CA farmers.
6. Two-row planter: Introduction of two row minimum till planters for
use by CA participants to plant their larger CA trials and their own CA fields.
Water:
1.Rainfall (rain gauges, weather stations, SAEON)
2.Run-off (run-off pans)
Soil:
1.Bulk density (field measurements)
2.Soil health (Haney tests –Soil Health Solutions)
3.Nematodes (Indices NWU)
Productivity
1.Water productivity (soil data- CEDARA), yield data-
MDF)
2.Yields (Maize, beans, cover crops)
Data collection for the following variables
Collaboratively managed trials (CMTs)
-45 CMTs
-73 10x10’s
-119 strips
-29 Fodder
-44 short season maize
-25 seed and poultry
-22 two row planter
Water:rainfallandrunoff
Oct Nov Dec Jan Feb Marc
hApril Total
s
Rainfall 2019/20 (mm);
Weather Station SAEON –
Didima
131,0172,6143,599,1 86,1 49,2 17,7699,2
Rainfall2020/21(mm);
Weather station SAEON -
Didima
103,4 207,0 204,7 409,2 197,1 101,648,01270,9
0,0
200,0
400,0
600,0
800,0
1000,0
1200,0
1400,0
mm rainfall
Monthly rainfall averages in 1029/20 and 2020/21 in
Bergville
rainfall (mm)
runoff CA plot (L)
runoff control plot
(L)
Bergville
(6 participants, 4villages)
Sum
1276
,7
76
,7
146
,1
%
rainfall conversion
6%
11
%
SKZN
(4 participants, 4villages)
Sum
505,8
12,3
18,4
%
rainfall conversion
2%
4%
Midlands
(3 participants, 3villages)
SUM
939
,1
37
,3
64
,1
%
rainfall conversion
4%
7%
-Overall rainfall for 2020/21 almost double that of 2019/20
-Periodicityisdifferent: For2020/21much more rainfalllater in the
season
-Late season rainfall (March-April) affected bean yields and caused
increased fungal load in maize grain
-Run-off averages across all CA trial
plots almost 50% lower than runoff in
the control plots (CA control maize-
mono cropped
Figure Right
and far right:
Installation of
run-off pans in
control and CA
trial plots,
respectively.
Figure Right: Signs of run-
off in a CA control M plot
in Bergville
SH results (Bergville) vary considerably between 2015-2020. the SH scores
decrease after drought years and also in years with late onset rains and mid-
season dry spells.
The high loss of Organic N and Organic C from the soil between 2019 and 2020
can be considered a combined effect of high temperatures early in the season,
leaching, due to extreme rainfall events mid to late season (January-March
2021) and reduced stover or soil cover, due to increased grazing pressure from
livestock because of dwindling grazing in the area.
Nematode indices indicate;
-A slow shift to amore fungal dominated soil ecosystem
-Increased structure and maturity of the nematode populations
-No significant differences inindices between CA treatments.Treatments are all
important and have different effects:SCC for example improve nematode
populations and linkages but push the ecosystem to amore bacteria
dominated system and M+B for example elan more towards low enrichment,
fungal dominated pathways.
-Structure and maturity indices for all treatments were high for agricultural
fields and much higher than indices found in conventionally tilled fields.
Soil: Soil health, nematode indices
CO2-C organic
N
Organic
CC/N %SOM
Soil
Health
Calculati
on
(Index)
Bergville 2015179,17,489,0 12,116,5
Bergville 201675,113,6 205,1 15,73,18,4
Bergville 2017100,821,1 302,3 13,43,316,6
Bergville 2018147,615,7 233,2 16,73,517,9
Bergville 201965,820,8 260,9 12,83,513,9
Bergville 202055,5 6,6146,528,5 3,19,1
0,0
50,0
100,0
150,0
200,0
250,0
300,0
350,0
SH parameters for 3 farmers from Bergville 2015-2020
Water productivity for CA maize grown as an intercrop with
beans or cowpeas is higher than single cropped CA maize and
Water productivity for CA plots is significantly higher than
conventionally tilled plots.
Despite annual differences in water productivity, these trends
remained the same across two seasons for all three areas
within KZN. WP for grain the M+CP intercropped plots is the
highest for both seasons
The close spacing used in the CA trial plots provides extra WP
benefits when compared to the ‘normal’ spacing used in
these villages
WP for grain and biomass follow the same trends, although
WP for the maize biomass is affected by the intercropping
with legumes. WP for biomass is the highest for the CA maize
only plots.
Cropping
options
WP
(kg/m3)
(kg/m3)
Ave
WP (
2
seasons)
2020
/21
(n=
11)
/20 (n=9)
CA
Maize (M)
2
,28
,11
1
,7
CA
-Maize, bean intercrop (M+B)
2
,50
,21
1
,9
CA
-Maize cowpea intercrop (M+CP)
2
,84
,43
2
,1
CA
-Maize control (M-CA control)
1
,1
,8
1
,0
Conventionally
tilled maize (M-
Conv
Control)
0
,75
,36
0
,6
Productivity:water productivity
MM+BM+CP M-CA
Control
M-Conv
Control
Averageof WPgrain(kg/m3)2,28 2,50 2,84 1,01 0,75
Averageof WPbiomass(kg/m3)2,56 2,29 1,28 0,82 0,88
0,00
0,50
1,00
1,50
2,00
2,50
3,00
WP kg/m3
Water productivity (grain and biomass of maize) for 11 participants in KZN
2020/21
WP was calculated for 11 participants across all three areas, for maize grain and biomass only.
WP for maize grown in a
multi-cropping rotation
CA systemis much higher
than CA mono-cropped
maize or conventionally
tilled maize
Averageyieldsformaize
planted in intercropped
plots (M+B , M+Cp, M+Pk)
are much higher than the
yields in maize only plots
AverageyieldsfortheCA
trial plots (intercropped
and maize only averaged)
are much higher than
maize yields in the CA
controlplots(planted to
maize only in consecutive
years)
Productivity:Yields(Bergville)
Eqeleni Ezibomvi
ni Stulwane Vimbukh
alo
Average of
yield(t/ha)CA-M 8,35 7,29 2,21 6,67
Average of
yield(t/ha)CA-M
intercrop
9,95 12,62 4,25
Average of
yield(t/ha)CA 9,21 7,90 2,96 6,67
Average of
yield(t/ha)Control 4,71 6,21 2,75 1,98
0,00
2,00
4,00
6,00
8,00
10,00
12,00
14,00
t/ha
Maize yields Bergville 2020/21 (N=28)
Yieldadvantagesfor
maize through
intercropping and crop
rotationareevident
after a continuous CA
implementation cycle of
4 or more years
For SKZN, maize harvests were separated
between CA trial plots (all) and the control
plots, but not between different CA
treatments. Yields for the CA trials were higher
than the control for 2 of the 5 villages.
Implementation for 3-4 years
For Midlands yields were separated for the
strips and blocks in CA trials and the controls.
Here the maize yields for the strip cropping
was much higher than the blocks and the
controls. Implementation here for 1-3 years,
with a strong preference for Strip planting and
also marked improvement in management for
the strips over the blocks
Productivity: Yields continued (SKZN and Midlands)
Yieldadvantagesformaize
through CA (all treatments) is
startingto becomeevident in
the two newer areas, but
requiresmorefocusand
separation of treatments going
into the future
Madzika
ne
Ngongo
nini Ofafa Plainhill Spring
Valley
Control 2,71 1,85 3,761,98
Trial 2,19 3,61 3,29 5,47 3,13
0,00
1,00
2,00
3,00
4,00
5,00
6,00
ton/ha
CA trial and control yields for SKZN 2020/21
Ozwathini Swayimane
10x10 2,68 1,36
Control 2,57 1,51
Strips 4,49 1,86
0,00
1,00
2,00
3,00
4,00
5,00
t/ha
Maize yields for Midlands CA experimentation
2020/21
Productivity; Incomegeneration
Average income per participant (Midlands), selling green mealies,
is around R2 000 from an average area of around 300m2of maize.
This would equate to an income of around R66 600/ha.
This is a significantly higher income potential than selling dry
maize per ton, which would equate to around R10 400 for the
2,6t/ha average for these farmers.
80% of participants have sold some of their maize and actual
incomes ranged from as little as R120 (400m2) to a maximum of
R39 550 (2700m2)
Village
name
Income
from
Green
Maize
Total
income/area
Ozwathini
Gobinsimbi
R
1890,00
Hlathikhulu
R
1200,00
Mbalenhle
R
1650,00
Mkhakhasini
R
2700,00
Swidi
R
7620,00
R
15 060,00
Swayimane
Gobizembe
R
1800,00
Mayizekanye
1
R
17 965,00
Mayizekanye
2
R
5237,00
Mayizekanye
3
R
59 807,00
R
84 809,00
Grand
Total
R
99 869,00
Mycotoxins
A total of 36 samples were taken from 10
participants across all three areas. Of these 9
samples contained high levels of mycotoxins and
10 samples contained no mycotoxins. 15 Samples
contained low levels of a range of mycotoxins. All
mycotoxinswereproducedbyFusariumspp.
(Fumosins B1-3, DON, ZEN)
Mycotoxin levels in maize for CA plots
intercropped with beans were low and much
lower than some of the maize only plots.
The results indicate an urgent need to work with
smallholder farmers on strategies to reduce
mycotoxin levels in their maize, both in their
fields and in subsequent storage methods and
processes.
Cover crop options:
1. Blocks or strips of SCC mix (fodder sorghum, sun hemp, sunflower), Dolichos and WCC mix (saia
oats, fodder rye and fodder radish)
2. Strips of fodder species, annual (Teff, turnips) and perennial (Lespedeza, Tall Fescue
Productivity: Livestock integration-Cover crops
Grazing cover crops or stover in situ
Collection of stover for baling and grazing and
Cutting of veld grass for baling and stover
Productivity: Livestock integration – Grazing, fodder
Multi-cropping and crop rotation in smallholder CA systems leads
to:
-Significantly reduced runoff
-Slight reductions in bulk density of soil
-Significantly improved WP for maize and
-Significantly improved yield potential for maize
But soil health improvements are constrained by weather
variability, lack of soil cover and reluctance to increase crop
diversity beyond the 2-3 crops that people habitually plant for
foodproduction
Conclusion