Matching fertiliser inputs of both macro- and micronutrients to crop target yield and quality will maximise the crop’s competitive ability against weeds. Macronutrients (including N, P, K, S, Ca, Mg) are most important for plant growth. Ensure that these nutrients are in good supply before considering the micronutrients (Cu, Zn, Mn, Fe, Mo, B, Cl). In some locations there may be known deficiencies of some micronutrients that need to be addressed for either good plant growth or subsequent animal growth.
Fertiliser placement can improve crop growth, yield and competitive ability. Aim to place fertiliser nutrients, in both space and time, where they are most available to the crop plants to optimise competitive ability. Without exposing germinating seed to toxicity risks, a three-hopper sowing machine allows placement of an N–P–(K) starter fertiliser with the seed, while extra nitrogen (N) is banded below, to avoid toxicity. The banding depth will also affect both soil disturbance (see Row spacing) and depth control (see Sowing depth).
The focused application of N (in method and timing) reduced the production of excessive weed biomass and limited weed seed production and subsequent replenishment of the weed seedbank.
Modelling weed-crop competition allows for numerous factors to be taken into account which may not otherwise be possible in the field. Modelling allows predictions to made based on the best evidence available at any given time. It allows influences of climate, economics, soil health, weed, crop and environmental ecology and other numerous features to be simulated in order to produce possible outcome interactions.
Article: CulturalWeedControl176 (permalink) Date: 9 January 2013; 7:51:01 PM AEDT