Grain-SA Smallholder Farmer Innovation Programme Erna Kruger, Ngcobo P, Dlamini M and Smith H Learning Conservation Agriculture the Innovation Systems way
CA-Farmer Innovation Programme Key objectives and activities Stakeholder interaction, partnerships, horizontal Farmers days, Awareness raising and and vertical scaling symposiums, cross Access to Information visits, conferences, popular articles Learning groups; practical demonstrations, Farmer-centred workshops, field Incentives and Education assessments Innovation Market Based and Training Mechanisms System Subsidies, Village Farmer experimentation; Saving and Loan On-farm, intercropping, crop Associations, farmer farmer-led rotation, cover crops, centres, group based Research livestock integration. access to equipment and infrastructure
Trial summaries over 5 seasons; Bergville,SKZN and EC CA Farmer led Trial summaries Midlands Bergville EC, SKZN Season 2017 2013 2014 2015 2016 2017 2013 2014 2015 2016 2017 No of villages 6 3 9 11 17 18 4 10 8 8 13 No of trial participants 42 28 83 73 212 259 23 16 43 54 93 Area planted (trials) - ha 1,36 2,8 7,2 5,9 13,5 17,4 0,36 0,3 0,37 1,18 3,58 Average yield maize (t/ha) 2,04 3,74 3,63 4,12 5,03 5,7 0,95 0,7 1,37 2,52 2,17 Min and max yield maize (t/ha) 0,4-7,1 2-4,3 1-6,7 0,6-7,4 0,3-11,7 0,5-12,2 0,3-1,7 0,3-1,8 0,5-4,4 1,1-5,2 0,2-6,7 Average yield beans (t/ha) 0,62 1,24 0,26 0,79 1,05 1,22 1,26 0,34 0,69 1,28 0,35
The CA system and effect on soil fertility and soil health Intercropping with • For CA plots the pH is higher on average and acid legumes (beans and saturation lower than on cowpeas) and use control plots of cover crops • The required P has reduced increase soil fertility on CA plots • And % Org C and % N and soil health increased significantly FASTER than compared to control plots monocropping • Savings of around R400/ha made on inorganic N in three seasons • C:N ratios in the soil decrease over time for the CA plots Increased % • Soil health scores are higher Organic C and % for CA plots than control N under CA plots
Soil health; methods • Visual and quantitative indicators • Visual Soil Assessments: soil cover, soil structure, run-off, crusting, earthworms, root size, soil porosity, soil texture • Measurements: infiltration, run-off plots, weather stations • Soil health analysis
Soil health(SH) scores CO 2 /10+WEOC/50 +WEON/10 =SH • WEOC – sugars from root exudates, score plus organic matter degradation • CO 2 – microbial activity/respiration • Developed by Rick Haney – to • WEON – Atmospheric N 2 sequestration accommodate for and include the from free living N fixers, plus SOM organic fractions of nutrients in soil sample analysis degradation • Recognising that soil health is a • C/N – Balance between WEOC and dynamic process of cycling of nutrients, WEON microbial activity and degradation of • MAC% - efficiency of cycling of WEOC organic matter (WEOC/CO 2 -C) • And the plant roots are active participants in the cycling providing Joining soil science and carbon sugars as root exudates to ecology into a new supply microbes with food science of soil health
Test results N-Mineralisation Potential Biomass What the values mean CONVENTIONAL SYSTEM: Mostly ppmCO 2 -C decomposer fungi – small hyphal >100 High-N potential soil. Likely Soil very well supplied with organic networks, NB for soil fertility, minor sufficient N for most crops matter. Biomass>2500ppm role in carbon storage • C:N ratio is determined by soil chemical properties and micro organisms present in 61-100 Moderately-high. This soil has Ideal state of biological activity and CA SYTEM: Mostly Mycorrhizal fungi the soil. limited need for supplemental N adequate organic matter – large hyphal networks, major role • The lower this ratio is, the more organisms 31-60 Moderate. Supplemental N Requires new applications of stable in carbon storage are active and the more available the food is to the plants. Good C:N ratios for plant required organic matter. Biomass<1,200ppm growth are <15:1. 6-30 Moderate-low. Will not provide Low in organic structure and microbial • You can have a low or optimum C:N Mycorrhizal fungi get their sufficient N for most crops activity. Biomass<500ppm (WEOC/WEON) within a range of values of available organic carbon in the soil. (WEOC) energy in a liquid form, as soluble 0-5 Little biological activity; requires Very inactive soil. Biomass<100ppm. • If this value is low, it will reflect in the C0 2 carbon directly from actively significant fertilization Consider long-term care evolution, which will also be low. So less growing plants. They access and organic carbon means less respiration from transport water - plus nutrients Below: Mycorrhizal fungi grow very closely microorganisms, but again this relationship is unlikely to be linear. associated with plant roots and create such as phosphorus, nitrogen and networks of filaments (hyphae) within the soil) • The Microbially Active Carbon (MAC = WEOC zinc - in exchange for carbon from / ppm CO 2 ) content is an expression of this plants. relationship. If the percentage MAC is low, it means that nutrient cycling will also be low. Soluble carbon is also channelled One needs a %MAC of at least 20% for efficient nutrient cycling. into soil aggregates via the • hyphae of mycorrhizal fungi and The SH score ranges between 0-50. the scale is generally 0-3; 3-7; 7-15; 15-25; 25-50 can undergo humification, a process in which simple sugars are made up into highly complex carbon polymers .
Comparing the nitrogen profile of natural “veld” with an intensively chemically farmed plot . Distribution of the Nitrogen components ppm Distribution of the Nitrogen components ppm NO3, 1.10 Release from Orga, 1.00 NO3, 83.20 Total Inorganic, 86 Release from Orga, Total Inorganic, 11.5 NH4, 10.40 19.40 Reserve Organic, 7.4 NH4, 2.80 Reserve Organic, 0 BIOLOGICAL ANALYSES BIOLOGICAL ANALYSES SOLVITA Soil SOLVITA Soil WATER EXTRACT WATER EXTRACT CO2 Burst Health Commen CO2 Burst Health Commen Sample # C/N Sample # C/N Calculatio t CO2 - C, Organic C Organic N Calculatio t CO2 - C, Organic C Organic N n (Index) ppm C ppm C ppm N n (Index) ppm C ppm C ppm N 7.1 129 8.4 15.4 2.6 ENZV 206.1 379 19.4 19.5 24.2 Excellent % 1.3 Soil Organic Matter % 6.2 Soil Organic Matter 54.4 5.5 % % Microbial Active C (MAC) Microbial Active C (MAC)
Comparing the nitrogen profile of natural “veld” with CA diverse cropped plot; Bergville, 2016/17 . Distribution of the Nitrogen components ppm: Distribution of the Nitrogen components ppm; Veld (P Hlongwane) Maize + Cowpea intercrop (P Hlongwane) NO3, 0.30 NO3, 12.90 Total Inorganic, Total Inorganic, 3 NH4, 2.70 17.2 Release from Release from Orga, Orga, 18.40 21.20 NH4, 4.30 Reserve Organic, 4.2 Reserve Organic, 0 BIOLOGICAL ANALYSES BIOLOGICAL ANALYSES SOLVITA Soil SOLVITA Soil WATER EXTRACT WATER EXTRACT CO2 Burst CO2 Burst Health Commen Health Commen Sample # C/N Sample # C/N CO2 - C, Organic C Organic N Calculatio t CO2 - C, Organic C Organic N Calculatio t n (Index) ppm C ppm C ppm N n (Index) ppm C ppm C ppm N EPHMCP 61,8 296 25,4 11,7 14,6 EPHV 81,6 326 18,4 17,7 16,5 Excellent Excellent % 4 % 3,3 Soil Organic Matter Soil Organic Matter % % Microbial Active C (MAC) 25 Microbial Active C (MAC) 20,9
Comparing the nitrogen profile of Mono-cropped Maize with CA diverse cropped plot; Bergville, 2016/17 . Distribution of the Nitrogen components ppm; Distribution of the Nitrogen components ppm; CA Maize control (P Hlongwane) Maize + Cowpea intercrop (P Hlongwane) Release from NO3, 12.90 Orga, 21.70 NO3, 16.10 Total Inorganic, Total Inorganic, 18.4 17.2 Release from Orga, 21.20 NH4, 4.30 Reserve Organic, NH4, 2.30 Reserve Organic, 1.5 4.2 BIOLOGICAL ANALYSES BIOLOGICAL ANALYSES SOLVITA SOLVITA Soil Soil WATER EXTRACT WATER EXTRACT CO2 Burst CO2 Burst Health Commen Health Comme Sample # C/N Sample # C/N Calculatio nt Calculatio t CO2 - C, Organic C Organic N CO2 - C, Organic C Organic N n (Index) ppm C ppm C ppm N n (Index) ppm C ppm C ppm N EPHC 59,6 254 23,2 10,9 13,4 EPHMCP 61,8 296 25,4 11,7 14,6 Excellent Excellent % 3,3 % 3 Soil Organic Matter Soil Organic Matter % Microbial Active C (MAC) 20,9 % Microbial Active C (MAC) 23,5
Mphumelele Hlongwane- Ezibomvini Bergville: Case study • 4-5 years: Reduced need for herbicide - no spraying on trial plots this season • Increased organic matter, reduced fertilizer requirements - No basal fertilizer applied- only top dressing • Reduced runoff • Increased yields and diversity
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