scholarly journals Longitudinal analysis of a long-term conservation agriculture experiment in Malawi and lessons for future experimental design

2020 ◽  
Vol 56 (4) ◽  
pp. 506-527 ◽  
Author(s):  
R. M. Lark ◽  
I. S. Ligowe ◽  
C. Thierfelder ◽  
N. Magwero ◽  
W. Namaona ◽  
...  

AbstractResilient cropping systems are required to achieve food security in the presence of climate change, and so several long-term conservation agriculture (CA) trials have been established in southern Africa – one of them at the Chitedze Agriculture Research Station in Malawi in 2007. The present study focused on a longitudinal analysis of 10 years of data from the trial to better understand the joint effects of variations between the seasons and particular contrasts among treatments on yield of maize. Of further interest was the variability of treatment responses in time and space and the implications for design of future trials with adequate statistical power. The analysis shows treatment differences of the mean effect which vary according to cropping season. There was a strong treatment effect between rotational treatments and other treatments and a weak effect between intercropping and monocropping. There was no evidence for an overall advantage of systems where residues are retained (in combination with direct seeding or planting basins) over conventional management with respect to maize yield. A season effect was evident although the strong benefit of rotation in El Niño season was also reduced, highlighting the strong interaction between treatment and climatic conditions. The power analysis shows that treatment effects of practically significant magnitude may be unlikely to be detected with just four replicates, as at Chitedze, under either a simple randomised control trial or a factorial experiment. Given logistical and financial constraints, it is important to design trials with fewer treatments but more replicates to gain enough statistical power and to pay attention to the selection of treatments to given an informative outcome.

Agronomy ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Liliane Ngoune Tandzi ◽  
Charles Shelton Mutengwa

Standardization of crop yield estimation methods at various levels of farming helps to obtain accurate agricultural statistics as well as assessing the suitability of agricultural practices under various production conditions. The current paper reviews various maize yield estimation methods, taking into account available yield parameters, and it also analyses the yield gap between maize potential and attainable yield. The easiest and more reliable methods of yield estimation are based on yield parameters collected from the field. However, farmer estimation methods are cheaper and faster compared to any other method of yield estimation from farmers’ fields. This paper also elaborates on the importance of the use of more complex methods for yield estimation, such as remote sensing and crop modelling. These complex methods are more accurate and can predict yield before field harvest with less deviation from the exact harvest yield. However, they are very expensive and not efficient for small plots of land (less than 1 ha). Factors that contribute to the gap between potential and actual yield include poor implementation of agricultural policies, strict regulation of fertilizer inputs, vulnerability of smallholder cropping systems to adverse climatic conditions, occurrence of biotic and abiotic constraints, as well as unavailability of seeds and labor.


2015 ◽  
Vol 31 (5) ◽  
pp. 414-428 ◽  
Author(s):  
Christian Thierfelder ◽  
Leonard Rusinamhodzi ◽  
Peter Setimela ◽  
Forbes Walker ◽  
Neal S. Eash

AbstractConservation agriculture (CA) based on minimum soil disturbance, crop residue retention and crop rotations is considered as a soil and crop management system that could potentially increase soil quality and mitigate the negative effects of climate variability. When CA is combined with drought-tolerant (DT) maize varieties, farmers can reap the benefits of both—genetic improvement and sustainable land management. New initiatives were started in 2007 in Mozambique to test the two climate-smart agriculture technologies on farmers' fields. Long-term trends showed that direct seeded manual CA treatments outyielded conventional tillage treatments in up to 89% of cases on maize and in 90% of cases on legume in direct yield comparisons. Improved DT maize varieties outyielded the traditional control variety by 26–46% (695–1422 kg ha−1) on different tillage treatment, across sites and season. However a direct interaction between tillage treatment and variety performance could not be established. Maize and legume grain yields on CA plots in this long-term dataset did not increase with increased years of practice due to on-site variability between farmer replicates. It was evident from the farmers' choice that, beside taste and good milling quality, farmers in drought-prone environments considered the potential of a variety to mature faster more important than larger potential yields of long season varieties. Population growth, labor shortage to clear new land areas and limited land resources in future will force farmers to change toward more permanent and sustainable cropping systems and CA is a viable option to improve their food security and livelihoods.


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.


2021 ◽  
Vol 7 (34) ◽  
pp. eabg6995
Author(s):  
Raphaël A. Wittwer ◽  
S. Franz Bender ◽  
Kyle Hartman ◽  
Sofia Hydbom ◽  
Ruy A. A. Lima ◽  
...  

Ecosystems provide multiple services to humans. However, agricultural systems are usually evaluated on their productivity and economic performance, and a systematic and quantitative assessment of the multifunctionality of agroecosystems including environmental services is missing. Using a long-term farming system experiment, we evaluated and compared the agronomic, economic, and ecological performance of the most widespread arable cropping systems in Europe: organic, conservation, and conventional agriculture. We analyzed 43 agroecosystem properties and determined overall agroecosystem multifunctionality. We show that organic and conservation agriculture promoted ecosystem multifunctionality, especially by enhancing regulating and supporting services, including biodiversity preservation, soil and water quality, and climate mitigation. In contrast, conventional cropping showed reduced multifunctionality but delivered highest yield. Organic production resulted in higher economic performance, thanks to higher product prices and additional support payments. Our results demonstrate that different cropping systems provide opposing services, enforcing the productivity–environmental protection dilemma for agroecosystem functioning.


2018 ◽  
Vol 10 (4) ◽  
pp. 320-332
Author(s):  
H.K. Prasai ◽  
S.K. Sah ◽  
A.K. Gautam ◽  
A.P. Regmi

Abstract. The adoption of Conservation agriculture (CA) contributes to sustainable production and its advantages include lower inputs and stable yields. This study was conducted in the research field of Regional Agricultural Research Station, Bhagetada, Dipayal, Doti during 2014 and 2015 to identify the effect of CA on grain yield and income of maize in Maize based cropping system. Both conservation and conventional agricultural (ConvA) practices were evaluated on two maize based cropping systems namely maize-wheat-mungbean (M-W-MB) and maize-lentil-mungbean (M-L-MB). For this purpose two maize varieties namely Raj Kumar and Arun-2 were used. The average productivity of maize under M-L-MB cropping system was 1.6% higher (5.75 t/ha) than M-W-MB cropping system (5.66 t/ha). The average grain yield of maize under CA was 16.7% higher (6.15 t/ha) than ConvA (5.27 t/ha). Rajkumar produced 43% higher average grain yield (6.73 t/ha) than Arun-2 variety (4.69 t/ha). The average net benefit was slightly higher (US$ 597.33/ha) under M-L-MB cropping system than M-W-MB cropping system (US$ 573.89/ha). Similarly, the average net benefit from CA was 102% higher (US$ 783.67/ha) than ConvA (US$ 386.79/ha). Rajkumar variety gave 127% higher average net benefit (US$ 813.49/ha) than Arun-2 (US$ 357.81/ha). The average benefit - cost (B:C) ratio of M-L-MB cropping system was slightly higher (1.72) than the average B:C ratio of M-W-MB cropping system (1.70). The average B:C ratio of CA was 42% higher (2.01) than ConvA (1.41). The average B:C ratio of Rajkumar variety was found 33% higher (1.95) than Arun-2 (1.46). The higher grain yield, net profit and B:C ratio were found in CA practices under M-L-MB cropping system and Rajkumar variety. This study suggests that hybrid maize planting and the adoption of M-L-MB cropping system should be used to increase grain yield and economic performance under CA practices.


Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 168
Author(s):  
John Sariah ◽  
Daniel Rodriguez

The agricultural sector in Tanzania is mainly dryland and dominated by smallholder farmers. Unreliable rainfall, short than normal duration of cropping season and fluctuations of onset and end of cropping season are main challenges facing farmers. The increased frequency and intensity of droughts, unpredictability of weather, shorter than normal duration of cropping seasons have significant impact on farmers’ productivity, profitability and resilience. This paper report study on Conservation agriculture for Sustainable Intensification (CASI) technology package tested on farm for productive, resilient and sustainable smallholder maize-legume cropping systems across five districts in Tanzania. Three practices namely Conservation practice (CA), Current applied recommended practice (CONV. or sometimes referred to as IMPROV) and primitive farmers practice (FP) were compared in experimental plots on farmers’ fields. Improved (DT maize and Pigeonpeas) was intercropped in all practices. Only CA and CONV practices were statistically compared, whereas FP was for farmer’s visual observations and comparisons. Data recorded were, soil carbon, moisture, yields and economic analysis. Results showed that, the average maize yields for four seasons in CA and CONV doubled and for tripled. An average of 30.5% hours of labour were saved in CASI relative to non CASI practice. The benefit cost ratio of maize-pigeonpea intercrops under CASI was 2.1 as compared to 1.4 in conventional agriculture investments. The institutionalization of CASI at local and national policy decision levels will be required for the scaling of CASI technologies across Tanzania.


2019 ◽  
Vol 35 (3) ◽  
pp. 322-335 ◽  
Author(s):  
W. Mupangwa ◽  
C. Thierfelder ◽  
S. Cheesman ◽  
I. Nyagumbo ◽  
T. Muoni ◽  
...  

AbstractConservation agriculture (CA) and no-till (NT)-based cropping systems could address soil degradation and fertility decline in southern Africa. A multi-location and multi-year experiment was carried out between 2008 and 2014 to assess the effects of different levels of maize residue biomass (0, 2, 4, 6 and 8 t ha−1) and nitrogen (N) fertilizer (0, 30, 90 kg ha−1) on maize performance under no-tillage. In some sites, different (N) fertilizer levels were superimposed to test their effects on maize grain yield and leaf chlorophyll content under different maize residue biomass levels. The different residue levels had no significant effect on maize yield in most growing seasons. Maize residue cover increased grain yield in eight out of 39 site-years across the sites used. However, in some sites, maize yield decreased with increases in residue level in cropping seasons that had average to above average rainfall. At a few sites maize yield increased with increase in residue level. Seasonal rainfall pattern influenced the effect of different residue levels on grain yield at most sites. Nitrogen fertilizer increased maize yield regardless of the residue level applied. This study demonstrates that mulching with maize residues in CA/NT systems results in limited maize yield gains – at least within the first 6 years in different agro-ecological conditions of southern Africa.


2015 ◽  
Vol 105 (3) ◽  
pp. 275-290 ◽  
Author(s):  
Isaiah Nyagumbo ◽  
Siyabusa Mkuhlani ◽  
Charity Pisa ◽  
Donwell Kamalongo ◽  
Domingos Dias ◽  
...  

2006 ◽  
Vol 42 (4) ◽  
pp. 441-457 ◽  
Author(s):  
F. K. AKINNIFESI ◽  
W. MAKUMBA ◽  
F. R. KWESIGA

Maize production in Malawi is limited by high costs and sub-optimal use of chemical fertilizers under continuous cultivation. A long-term gliricidia/maize trial was undertaken on a Ferric Lixisol from 1991/92 to 2001/02. The purpose of the study was to assess the performance of a gliricidia/maize intercropping system as a low-input soil fertility replenishment option in southern Malawi. The experiment was a 2 × 3 × 3 factorial design with three replications. Treatments included two maize cropping systems (with and without gliricidia trees), and three rates of inorganic N fertilizer (0, 24 and 48 N kg ha−1 representing 0, 25 and 50% of the national recommended N rate), and three rates of P fertilizer application (0, 20 and 40 P ha−1 representing 0, 50 and 100% of the recommended rate). No effect of P was detected on yield early in the trial, and this treatment was discontinued. The gliricidia pruning biomass did not decline after 10 years of intensive pruning, with strong correlation between tree biomass production and years after establishment (r = 0.91, p < 0.001). Application of gliricidia prunings increased maize yields by three times compared to the yield of unfertilized sole maize. Maize yield from the unfertilized gliricidia pruning treatment was superior to the yield from sole maize supplemented with a quarter or half the recommended N rate. The study confirmed that a gliricidia/maize intercropping system is a promising soil fertility replenishment option in southern Malawi and elsewhere in southern Africa.


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