Organic management promotes natural pest control through enhanced plant resistance to insects

Abstract

42Lower insect pest populations found on long-term organic farms have largely been 43 attributed to increased biodiversity and abundance of beneficial predators. However, 44 potential induction of plant defenses has largely been ignored. This study aims to 45 determine whether host plant resistance mediates decreased pest populations in 46 organic systems, and to identify the underpinning mechanisms. We demonstrate that 47Organic farming is characterized by management practices that promote biodiversity 82 and beneficial ecological interactions to offset synthetic inputs such as inorganic 83 fertilizers and biocides. Pest and nutrient management in organic agriculture is largely 84 accomplished through diversification methods such as cover crops, crop rotations, 85 and trap crops. Organic agriculture is often thought to be less productive in terms of 86 yield as compared to conventional farming, even though it offers great potential as a 87 more sustainable agricultural system (4, 5, 6) and can enhance the provision of 88 multiple ecosystem services, such as carbon sequestration, nutrient and water 89 retention, and biodiversity conservation (1-3). 90 91Accumulating evidence suggests that organic management practices also reduce pest 92 populations and increase resilience to pest damage (7-9). Enhancing natural pest 93 control in organic systems could help reduce costs, stabilize production, and increase 94 the ability of organic practices to meet global demand. Decreased insect pests on long-95

Improving evapotranspiration computation with electrical resistivity tomography in a maize field

“…where φ (m 3 m −3 ) is the porosity, ρ f (S m −1 ) is the pore water resistivity, b ([S m −1 ]/[meq cm −3 ]) is the equivalent ionic conductance of exchange cations, Q v (meq cm −3 ) is the cation exchange capacity per unit pore volume, CEC (meq g −1 ) is the cation exchange capacity (taken as 0.2529, measured by Blundell et al, 2020), and D soil (g cm −3 ) is the soil particle density (taken as 2.65). The model parameters, M [−] (cementation exponent) and N [−] (saturation exponent), were fitted with linear regression using the log-log form of the Waxman-Smits model (Equation 3a).…”