ON-FARM EVALUATION OF THE EFFECTS OF THE PRINCIPLES AND COMPONENTS OF CONSERVATION AGRICULTURE ON MAIZE YIELD AND WEED BIOMASS IN MALAWI

2014 ◽  
Vol 50 (4) ◽  
pp. 591-610 ◽  
Author(s):  
A. R. NGWIRA ◽  
JENS B. AUNE ◽  
C. THIERFELDER

SUMMARYAn on-farm study was conducted from 2009 to 2012 with communities in the Manjawira, Mpingu and Zidyana Extension Planning Areas in the Ntcheu, Lilongwe and Nkhotakota districts of central Malawi. The aim of the study was to evaluate the effects of the principles (no-tillage and mulching) and components (fertilization and weeding) of conservation agriculture (CA) on crop productivity and weeds, and the interactions between principles and components, and to suggest strategies for introducing CA to smallholder farmers. The treatments consisted of tillage, fertilizer application, residues management and weed control strategies. While combined analysis showed that mulching is as effective as tillage in controlling weeds, the interaction between site and treatment revealed that in the more humid environment of Zidyana, weed dry matter obtained under no-tillage and residues plus fertilizer (NT+F+R) was 0.6 mg ha−1lower than under CP+F. Results suggest that about 6.0 mg ha−1of mulch is required to have a similar effect as tillage in controlling weeds. Fertilizer had an overriding effect on maize yield, regardless of tillage and crop residue management. Mulching was beneficial over tillage in the drier environment of Manjawira, where maize yield obtained under NT+F+R was 1.2 mg ha−1greater than under CP+F. Our results show that the introduction of no tillage has benefits only if it is accompanied by fertilizer application, retention of crop residues as surface mulch, and improved weed control. Increasing availability and accessibility of inputs (fertilizers and herbicides) to farmers is critical for adoption of CA at scale in Malawi.

2016 ◽  
Vol 32 (1) ◽  
pp. 87-103 ◽  
Author(s):  
W. Mupangwa ◽  
M. Mutenje ◽  
C. Thierfelder ◽  
I. Nyagumbo

AbstractContinuous conventional tillage coupled with unsystematic cereal/legume rotations has promoted low crop productivity on smallholder farms. A multi-locational study was established in three agro-ecoregions (AEs) of Zimbabwe. The aim of the study was to determine the effect of four tillage systems (conventional plowing, planting basins, rip-line and animal traction direct seeding systems) on maize (Zea mays L.), cowpea [Vigna unguiculata (L.) Walp] and soybean [Glycine max (L.) Merrill] yields, and evaluate the economic performance of the conservation agriculture (CA) systems relative to conventional plowing. Each farmer was a replicate of the trial over the three cropping seasons. In the high (750–1000 mm per annum) and low (450–650 mm) rainfall AEs, conventional practice and CA systems gave similar maize grain yield. Under medium rainfall conditions (500–800 mm) planting basins, rip-line and direct seeding systems gave 547, 548 and 1690 kg ha−1 more maize yield than the conventional practice. In the high and low rainfall AEs, conventional practice and planting basins had the lowest maize production risk. Cowpea yield was 35 and 45% higher in the rip-line and direct seeding than conventional practice. Soybean yield was higher in rip-line (36%) and direct seeding (51%) systems than conventional practice. Direct seeding system gave the highest net benefits in all AEs. A combination of long-term biophysical and socio-economic assessments of the different cropping systems tested in our study is critical in order to fully understand their performance under different AEs of Zimbabwe.


2022 ◽  
pp. 270-283
Author(s):  
Christian Thierfelder ◽  
Peter Steward

Abstract Climate change and soil fertility decline are threatening food security in southern Africa and efforts have been made to adapt current cropping systems to the needs of smallholder farmers. Conservation Agriculture (CA) based on minimum soil disturbance, crop residue retention and crop diversification has been proposed as a strategy to address the challenges smallholder farmers face. Here we analyse the potential contributions of CA towards adaptation to the effects of climate change by summarizing data on infiltration, soil moisture dynamics and crop productivity under heat and drought stress. The data were taken in the main from CIMMYT's on-farm and on-station trial network. Data show that CA systems maintain 0.7-7.9 times higher water infiltration than the conventional tilled system depending on soil type, which increases soil moisture during the cropping season by 11%-31% between CA treatments and the conventional control treatment. This leads to greater adaptive capacity of CA systems during in-season dry spells and under heat stress. A supporting regional maize productivity assessment, analysing the results of numerous on-farm and on-station experiments, showed that CA systems will outperform conventional tillage practices (CP), especially on light-textured soils, under heat and drought stress. With higher rainfall and low heat stress, this relation was more positive towards CP and on clay soil there was no benefit of practising CA when rainfall was high. The long dry season and limited biomass production of CA systems in southern Africa require complementary good agricultural practices to increase other soil quality parameters (e.g. increased soil carbon) to maintain higher productivity and sustainability over time. This can be addressed by combinations of improved stress-tolerant seed, targeted fertilization, inclusion of tree-based components or green manure cover crops in the farming system, scale-appropriate mechanization and improved weed control strategies.


Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 605
Author(s):  
Sibongiseni Mgolozeli ◽  
Adornis D. Nciizah ◽  
Isaiah I. C. Wakindiki ◽  
Fhatuwani N. Mudau

Soil degradation is the greatest threat to agricultural production globally. The practice of applying or retaining crop residues in the field as mulch is imperative to prevent soil erosion, maintain soil quality and improve crop productivity. However, smallholder farmers resort to maximizing profit by removing crop residues after harvest to sell or use them as feed for livestock. Agrimats are innovative pro-smallholder farming mulching materials that are manufactured using cheap or freely available organic waste materials. These materials include forestry waste, grasses, etc., therefore allowing smallholder farmers to make more profit through improved crop productivity for better food security. The most notable attributes of agrimats include their ability to prevent soil erosion, increase and sustain soil organic matter, suppress weeds, and conserve soil moisture. Food security challenge can be addressed by adopting agrimat technology as a sustainable permanent soil cover to improve soil quality and crop productivity. Agrimat incorporation in conservation agriculture practice could produce more food from less input resources (chemical fertilizers, water, etc.) with minimal or no adverse effect on the environment. This study aims to advocate permanent soil cover using agrimat as an innovative pro-smallholder farmer technology to improve soil quality for better food security.


2012 ◽  
Vol 28 (4) ◽  
pp. 350-363 ◽  
Author(s):  
Amos Robert Ngwira ◽  
Christian Thierfelder ◽  
Dayton M. Lambert

AbstractConservation agriculture (CA) systems are based upon minimal soil disturbance; crop residue retention and crop rotation and/or intercrop association are increasingly seen to recycle nutrients, increase yield and reduce production costs. This study examines the effects of CA practices on crop productivity, profitability and soil quality under the conditions encountered by smallholder farmers in two farming communities from 2005 to 2011 in Malawi, as part of the contribution to remedy a lack of supporting agronomic research for these relatively new systems. The drier agroenvironment of Lemu of Bazale Extension Planning Area (EPA) is characterized by sandy clay loam soils and lower rainfall. Here, CA showed positive benefits on maize yield after the first season of experimentation, with highest increases of 2.7 Mg ha−1 and 2.3 Mg ha−1 more yield in CA monocrop maize and CA maize–legume intercrop, respectively, than the conventional tillage in the driest season of 2009/10. In the high rainfall environment of Zidyana EPA (characterized by sandy loam soils), substantial maize yield benefits resulted in the fifth season of experimentation. Farmers spent at most 50 days ha−1 (US$140) producing maize under CA systems compared with 62 days ha−1(US$176) spent under conventional tillage practices. In Lemu, both CA systems resulted in gross margins three times higher than that of the conventional control plot, while in Zidyana, CA monocrop maize and CA maize–legume intercrop resulted in 33 and 23% higher gross margins, respectively, than conventional tillage. In Zidyana, the earthworm population was highest (48 earthworms m−2 in the first 30 cm) in CA monocrop maize, followed by a CA maize–legume intercropping (40 earthworms) and lowest (nine earthworms) in conventionally tilled treatment. In both study locations CA monocrop maize and CA maize–legume intercrop gave higher water infiltration than the conventional treatment. Improvements in crop productivity, overall economic gain and soil quality have made CA an attractive system for farmers in Malawi and other areas with similar conditions. However, for extensive adoption of CA by smallholder farmers, cultural beliefs that crop production is possible without the ubiquitous ridge and furrow system and residue burning for mice hunting have to be overcome.


Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.


2021 ◽  
Vol 262 ◽  
pp. 108038
Author(s):  
Olabisi Omolara Onasanya ◽  
Stefan Hauser ◽  
Magdalena Necpalova ◽  
Felix Kolawole Salako ◽  
Christine Kreye ◽  
...  

Author(s):  
R. K. Naresh ◽  
S. S. Dhaliwal ◽  
M. S. Chandra ◽  
S. K. Malhotra ◽  
J. Harish ◽  
...  

Residues of various crops are considered nuisance but they can be helpful in increasing organic matter in soil and better cycling of nutrients in soil if managed properly. Better management and utilization of crop residues (CR) is necessary for better productivity and quality of crops. Sowing into loose residues is the major issue in adapting the drill sowing method. Apart from the higher quantity of rice (192.82 mt) and wheat residue (120.70 mt), the residue of sorghum, maize, barley, chickpea, groundnut, rapeseed, mustard, sugarcane trash, potato, soybean, sunflower and some other minor cereals also contribute substantially towards total amount of about 462.93 million tonnes in India in 1997-98. Three quarters of the total residue is produced by rice, wheat and oil seed crops with remaining quarter coming from sugarcane and sorghum. Crop residue is important component of low external input for sustainable agriculture without sacrificing productivity. The crop residues left behind is considered as burden forcing farmers to burn them as cheap and easiest method with mistaken belief that it enhances the soil fertility and helps in controlling weeds, insects and pests. Different studies revealed that burning of residues causes air pollution and nutrient loss in soil. Improvements in soil properties and the sustainability in crop productivity could be achieved if CR are proper managed. Long-term field studies at sites carefully selected with variations in temperature, moisture, soil mineralogy and management of agricultural residues representing various cropping systems across regions should be identified and sustained. The possible benefits of crop residues for the improvement of degrading soil fertility would be completely understood only then. Owing to the competing requirements for such biomass for feed, fuel or building material, smallholder farmers typically find it difficult to maintain a soil cover for crop residue or a cover crop.


2021 ◽  
Author(s):  
Micaela Tosi ◽  
John Drummelsmith ◽  
Dasiel Obregón ◽  
Inderjot Chahal ◽  
Laura L. Van Eerd ◽  
...  

Abstract Sustainable agricultural practices such as crop diversification, cover crops and residue retention are increasingly applied to counteract detrimental effects of agriculture on natural resources. Since part of their effects occur via changes soil microbial communities, it is critical to understand how these respond to different practices. Our study analyzed five cover crop (cc) treatments (oat, rye, radish, rye-radish mixture and no-cc control) and two crop residue management strategies (retention/R+ or removal/R-) in an 8-year diverse horticultural crop rotation trial from ON, Canada. Cc effects were small but stronger than those of residue management. Radish-based cover crops tended to be the most beneficial for both microbial abundance and richness, yet detrimental for fungal evenness. Cc species, in particular radish, also shaped fungal and, to a lesser extent, prokaryotic community composition. Crop residues modulated cc effects on bacterial abundance and fungal evenness (i.e., more sensitive in R- than R+), as well as microbial taxa. Several microbial structure features, some affected by cc, were correlated with early tomato growth in the following spring (e.g., composition, taxa within Actinobacteria, Firmicutes and Ascomycota). Our study suggests that, whereas mid-term cc effects were small, they need to be better understood as they could be influencing crop productivity via plant-soil feedbacks.


2017 ◽  
Vol 34 (5) ◽  
pp. 380-394 ◽  
Author(s):  
W. Mupangwa ◽  
M. Mutenje ◽  
C. Thierfelder ◽  
M. Mwila ◽  
H. Malumo ◽  
...  

AbstractClimate variability and declining soil fertility pose a major threat to sustainable agronomic and economic growth in Zambia. The objective of this study was to assess crop yield, land and labor productivity of conservation agriculture (CA) technologies in Eastern Zambia. On-farm trials were run from 2012–2015 and farmers were replicates of a randomized complete block design. The trials compared three CA systems against a conventional practice. Yield and net return ha−1 were determined for maize and legume yield (kg ha−1) produced by ridge and furrow tillage, CA dibble stick planting, CA animal traction ripping and direct seeding. The dibble stick, ripline and direct seeding CA systems had 6–18, 12–28 and 8–9% greater maize yield relative to the conventional tillage system, respectively. Rotation of maize with cowpea and soybean significantly increased maize yields in all CA systems. Intercropping maize with cowpea increased land productivity (e.g., the land equivalent ratio for four seasons was 2.01) compared with full rotations under CA. Maize/cowpea intercropping in dibble stick CA produced the greatest net returns (US$312-767 ha−1) compared with dibble stick maize-cowpea rotation (US$204-657), dibble stick maize monoculture (US$108-584) and the conventional practice (US$64-516). The net-return for the animal traction CA systems showed that maize-soybean rotations using the ripper were more profitable than the direct seeder or conventional ridge and furrow systems. Agronomic and economic benefits of CA-based cropping systems highlight the good potential for improved food security and agricultural productivity for smallholder farmers.


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