Consequences of Dryland Maize Planting Decisions Under Increased Seasonal Rainfall Variability

Abstract

In semiarid and arid regions of sub-Saharan Africa rising temperatures and shifting rainfall patterns are projected to negatively impact agricultural output (Downing et al., 1997;Branca et al., 2011;Müller et al., 2011;Slingo et al., 2005). Changes in rainfall associated with climate variability directly impact crop growth as storms are projected to become more intense with longer periods between rainfall events (Donat et al., 2016;Harrison et al., 2019;Meehl et al., 2007). The stochastic nature of rainfall during the growing season leaves crops susceptible to water stress during critical stages of development and can lead to crop failure (Sah et al., 2020;Salgado-Aguilar et al., 2020). Small rainfed farms cultivated by single families on plots less than 5 ha represent the most prevalent form of agriculture in sub-Saharan Africa and are particularly vulnerable to climate variability and change (Samberg et al., 2016). Because of their dependence on rainfed agriculture (Dinar et al., 2008), smallholder livelihoods are susceptible to climate shocks that affect food prices (Ray et al., 2012), variability in production and supply (Lobell et al., 2011;Slingo et al., 2005), and farmer incomes (Reidsma et al., 2010).Farmers make a variety of choices before and during the growing season that impact their agricultural production and thus food security and livelihood. Cultivar choice is one of the most critical choices a smallholder makes (Kalanda-Joshua et al., 2011). Because of the uncertainty associated with climate variability, farmer decision-making is becoming increasingly complex and uncertain at the expense of input use efficiency and profitability (Hansen et al., 2011;Guido et al., 2020;Waldman et al., 2019). Management options that were optimal for past or average climatic conditions may no longer be suited for increasingly common growing season weather. Additionally, traditional crop varieties may no longer be best suited for a farmer's environment, which has led to the development of hybrid and fast growing varieties (Smale & Jayne, 2010). Given ongoing changes in rainfall patterns, farmers need to select cultivars well suited for their local context that can lead to the greatest payoff in terms of yield while also minimizing the risk of crop failure. To date,

Maize Production under Drought Stress: Nutrient Supply, Yield Prediction

“…It causes an 8–10% reduction in chlorophyll content during the vegetative stage and 18% reduction during the reproductive stage [ 15 , 16 ]. It also alters genetic properties [ 17 ] and causes yield reduction [ 18 , 19 , 20 , 21 , 22 , 23 ]. Maize yield loss can vary from 30 to 90% depending on the intensity and duration of drought stress.…”

Changes in Climate Extremes and Their Effect on Maize (Zea mays L.) Suitability Over Southern Africa

“…This means that even if rainfall parameters remain the same or even increase under climate change, the changes in temperature will still result in decreases in crop suitability and thus lower production. Decreases in rainfall variability and resulting changes in available soil moisture affect crop potential (Krell et al, 2021), but temperature impacts are both direct on the crop and also indirect through effects on water supply and demand through altering vapor pressure deficit (Lobell et al, 2011;Sánchez et al, 2014;Hatfield, 2016). As such, the negative effects of future warming is expected to outweigh those of precipitation changes, as shown in our study.…”

“…Further, increases in temperature presents a double-edged sword effect on maize production. On one hand, it is responsible for heat stress on the plants and its associated biochemical and biophysical processes, while on the other hand, it mediates water supply through controlling evaporation and water demand through controlling canopy evapotranspiration (Zhang et al, 2009;Ge et al, 2012;Meng et al, 2016;Krell et al, 2021). It is not surprising that all the temperature extreme indices made it to the final modeling while for rainfall variables only CDD, which is positively correlated to temperature, remained.…”

“…Abiotic stress weakens the metabolic processes of maize by decreasing the photosynthetic rates, which results in reduced nutrient assimilation and biomass accumulation, resulting in morphological, physiological and biochemical changes that culminate in decreases in yield, and in severe cases result in plant death (Zhang et al, 2009;Song et al, 2019). However, it is not just the amount of water that is important for maize but its distribution during critical phenological stages (Omoyo et al, 2015;Krell et al, 2021). Water is the most limiting factor to maize production in many areas (Hossain, 2020) and the effects of water deficit are also mediated through temperature or soil conditions.…”

Influence of climate conditions on maize yield in Oltenia (1990-2021)

“…Besides the direct effects on the plant, high temperatures also determine the increase of evapotranspiration and, thus, the reduction of the available water resources, concomitantly with a higher plant water requirement (Lobell et al, 2014). The optimum rainfall amount for the interval May -August ranges between 280 and 380 mm (Muntean et al, 2001), but its distribution during the growing season is equally important (Krell et al, 2021). Consequently, as maize is a water-sensitive crop (Sah et al, 2020), water deficit (dry stress), especially during the critical phenological stages, such as flowering, including tasseling, silking and pollination, and grain filling, may cause up to 90% yield loss (Leng, 2021).…”