Conservation agriculture systems.

Abstract

Despite positive trajectories in global production during the last century, projected food demand and limits on our ability to further expand cropland now dictate an increase in food production by roughly 70% during the first half of the twenty-first century. Conventional systems of agriculture with their general emphasis on intensive soil disturbance, limited biodiversity, monoculture cropping and practices that mine the resource base are extractive and have resulted in slow yet demonstrably severe environmental degradation that ultimately jeopardizes food security for future generations. Because future gains in production are unlikely to be achieved by further increases in genetic yield potential, as have been achieved in the past, applications of new production system paradigms are going to be indispensable. Our existing ones are no longer able to compensate for, nor reverse, the environmental problems they have caused. We summarize the history of how agricultural systems have come to be what they are today and identify ways in which these systems will need to be improved to meet future food security challenges. We describe the development of food production system options that have been proposed in recent decades and show that the core principles and concepts of what are widely regarded as conservation agriculture (CA) systems provide an important unifying framework. Our chapter provides evidence for why these systems, when flexibly applied and in ways that mimic natural ecosystems, provide a best-bet approach for moving forward. We highlight a series of examples of CA systems being applied around the world and conclude by issuing a call to action aimed at developing and more widely adopting food production systems that look long-term, mimic natural systems and transcend jargon.

No-Till Farming and Conservation Agriculture in South Asia – Issues, Challenges, Prospects and Benefits

“…From the literature, it is also apparent that even a reduction in tillage and crop residue retention leads to enhanced chemical, microbial activity microbial biomass and enzymatic activies (Fluorescein diacetate, dehydrogenase, b Glucosidase, and Alkaline phosphatase) as compared to soils under CT (Ghosh et al, 2010;Singh et al, 2018;Choudhary et al, 2018a;Somasundaram et al, 2019;Nandan et al, 2019;Sharma et al, 2019) (Tables 3 and 4). Several authors reported that adopting CA practices including NT, crop residue retention coupled with optimum nutrient application increases SOC and total nitrogen stocks (Lal et al, 2015, Pasricha, 2017Bhattacharyya et al, 2013;2019) (Table 3). However, some authors have pointed out the conversion of CT to NT with crop residue retention did not increase SOC stocks/ sequestration (Srinivasarao et al, 2015;Dey et al, 2016).…”

“…CA practices affect runoff and soil erosion processes by improving soil structure, increased infiltration, less evaporation loss, and decreased bulk density and crusting Ordoñez-Morales et al, 2019;Mitchell, 2019) (Figure 9). Soil loss could be efficiently reduced with the adoption of conservation tillage practices in SA countries ( Figure 10) where it could minimize the annual soil loss rate upto 60% (Strauss et al, 2003).…”

Small-scale integrated farming systems can abate continental-scale nutrient leakage

“…Most proposed routes to achieving such putative less resource-intensive beef envision small to medium mixed-use farms, in which cattle are a cornerstone element on account of promoting local recycling of nutrients and thus “soil building” [ 27 , 28 ]. Because on timescales up to a decade the mineral component of soil is approximately fixed, this rather vague idea addresses organic components of soil and thus biogeochemical cycling [ 29 – 33 ].…”

Strategies to terminate summer cover crops for weed management in no-tillage vegetable production in southeast Brazil

“…Vegetable production in Brazil is grounded in conventional systems involving intense tillage and the high use of agricultural inputs, which have environmental impacts such as soil erosion and contamination and the eutrophication and siltation of water resources. However, there are current agronomic techniques, such as those outlined in conservation agriculture (CA), that focus on minimal soil disturbance, permanent organic mulching on the soil surface, and crop rotation, which significantly reduce the environmental impacts (Mitchell et al 2019;Palm et al 2014).…”