Response of Maize (Zea mays L.) Secondary Growth Parameters to Conservation Agriculture and Conventional Tillage Systems in Zimbabwe

Abstract

<p>Previous, research focused mainly on the effects of conservation agriculture (CA) and conventional practices (CP) on crop yield mostly. A study was conducted at five sites in Zimbabwe from 2012 to 2014 to investigate effects of CA and CP practices on emergence, chlorophyll content, early vigour and grain yield of different maize varieties using 12 hybrids and 4 open pollinated varieties (OPVs). The experiment was laid as a 4 × 4 alpha lattice design with three replications. Emergence was higher under CA (75%) at University of Zimbabwe (UZ) in 2012/13 and Domboshawa Training Centre (DTC) (67%) compared to CP (71% and 39% respectively). Lower early plant vigour was observed under CA compared to CP at most sites. CA had lower leaf chlorophyll content during the early crop growth stages compared to CP. However, at some instances, CA had higher leaf chlorophyll content (45 units) than CP (35 units) at 78 days after sowing in Zimuto 2012/13. For maize yield, CA outperformed CP on a sandy loamy soil (3050 kg ha<sup>-1</sup> vs 2656 kg ha<sup>-1</sup>) and clay soil (4937 kg ha<sup>-1</sup> vs 4274 kg ha<sup>-1</sup>). However, on a sandy soil, CP outperformed CA (1764 vs 1313 kg ha<sup>-1</sup>). Our results suggest that tillage effects on early maize plant vigor, leaf chlorophyll content and the final yield can be site and season specific. Furthermore, a delay of nutrient release for plant uptake under CA systems was found and potentially implies investigations of new fertilization strategies for such cropping systems.</p>

Effects of maize residue and mineral nitrogen applications on maize yield in conservation-agriculture-based cropping systems of Southern Africa

“…Leaf chlorophyll concentration is one index that can be used to assess soil N supply to growing plants during the growing season (Pandey et al ., 2000; Liu and Wiatrak, 2011). Leaf chlorophyll content in maize can vary with tillage practices used, growth stage of plants and the quality of seasonal rainfall pattern (Hlatywayo et al ., 2016). Previous studies have shown that maize plants grown under CA-based systems can have lower leaf chlorophyll content compared to conventionally ploughed systems (Hlatywayo et al ., 2016; Mupangwa et al ., 2016 a ).…”

Phenotyping Conservation Agriculture Management Effects on Ground and Aerial Remote Sensing Assessments of Maize Hybrids Performance in Zimbabwe

“…While the literature related to CA is mostly focused on crop management, the study of the genetic crop adaptation is limited and usually concludes that the interaction between the tillage practice and the genotype is absent [7,[52][53][54]. Crops have been grown on conventional tillage for many years and genes governing the adaptation to CA either have been lost over time through untargeted selection or have become redundant [55].…”

Combining ability of physiological traits in forrage maize

“…It is worth pointing out that it is important to improve CO 2 assimilation, since about 90% of the plant dry mass originates from CO 2 fixation, through the photosynthesis process and the regulation of photosynthetic efficiency (Ali et al, 2014a;Magalhaes;Souza, 2009;Minow et al, 2018 table 3: Estimates of general combining ability (ĝ i and ĝ j ) and specific combining ability (ŝ ij ) of CO 2 assimilation (A) (µmol CO 2 m -2 s -1 ), of 24 maize genotypes evaluated in a 4x4 partial diallel at 42 and 63 days after emergence in the first crop season (DAE-1) and at 63 days after emergence in the second crop season (DAE-2), in Guarapuava-PR. The highest estimates of the SCA of stomatal conductance (gs) at 42 DAE-1 occurred in crossings LEM2 x 202-160.1 (0.21 mol m -2 s -1 ) and LEM2 x 203-218.3 (0.19 mol m -2 s -1 ), but they originate from genitors with GCA estimates negative or close to zero (Table 4), with moderate means (Supplement 2), indicating that the performnce of these genitors was not different from the general mean of the other genitors involved in the crossings (Hallauer;Carena;Miranda Filho, 2010;Hlatywayo et al, 2016).…”

“…Maize is a C4 plant, characterized by a mechanism of CO 2 concentration that involves a coordinated functioning between the mesophile and the bundle sheath cells (Retta et al, 2016). It presents a low point of CO 2 compensation, a high photosynthetic rate and low water consumption for the formation of fresh matter (Hlatywayo et al, 2016;Huang et al, 2017). This functioning confers a higher photosynthetic net rate if compared to a C3 plant, since it presents low water loss, it can be cultivated in hot environments with high luminous intensity, and it adapts well to the tropical climate due to its low or null photorespiration (Wu et al, 2016).…”