Pulse crops in rotation with cereals can be a profitable alternative to nitrogen fertiliser in central Queensland

Abstract

Empirical and simulation results from three crop rotations incorporating cereals, pulses and nitrogen (N) fertiliser application were examined over 4 years in a subtropical environment, central Queensland, Australia. The hypothesis was that pulse crops in rotation with cereals would be a viable alternative to applying N fertilisers and would improve farm business economic performance provided the yield potential of pulses were not compromised by planting into very low soil water situations. Empirical data and simulations with the Agricultural Production Systems Simulator model were used to give insights into the N contribution, yield benefit to cereals and overall economic performance of the inclusion of pulses into the rotation. The field trial rotations included: rotation 1: sorghum and wheat in an opportunity crop rotation (called cerealsonly), rotation 2; cereals grown following a fallow with a pulse crop immediately after (called cereal double-cropped pulse) and rotation 3, pulses grown following a fallow with a cereal crop immediately after (called pulse double-cropped cereal).Empirical and simulated results indicated that the cereal double-cropped pulse rotation produced the highest average annual gross margins using prices at that time. In the simulations, when pulse crops were included in the rotation, no additional N fertiliser was required and the lowest chance of negative gross margins was obtained. The cereal double-cropped pulse rotation produced the largest trial and simulated gross margins. The pulse double-cropped cereal rotation produced greater gross margins than the N-deficient cereals-only rotation but significantly lower than the cereal double-cropped pulse rotation. Simulations indicated that the cereals-only rotation could be made profitable when the soil was 'topped-up' to 100 kg available N/ha before planting, or by 40 kg N/ha to each cereal crop. Chickpea and mungbean contributed an average of 35 and 29 kg N/ha, respectively, in the field trial.A minimum of 100 mm of the stored soil water at planting was needed to reduce the risk of negative returns. By planting only when the soil contained adequate water, the cereal double-cropped pulse rotation may provide a valuable supplement to farm income while simultaneously reducing the need for N fertilisers on the cereals. Alternatively, in a rotation with cereals only, modest amounts of fertiliser N will maintain profitability with minimal levels of financial risk.

Hybridisation of Australian chickpea cultivars with wild Cicer spp. increases resistance to root-lesion nematodes (Pratylenchus thornei and P. neglectus)

“…They can also provide useful rotation breaks for some cereal diseases. In the northern grain region, chickpea is the principal grain legume and, compared with wheat, it is considered to increase the yield of following wheat through increased nitrogen supply and nitrogen-sparing (Herridge et al 1995;Dalal et al 1998;Cox et al 2010) and reduction in inoculum of Fusarium pseudograminearum O'Donnell & T Aoki, the causal organism of crown rot of cereals (Felton et al 1998).…”

Weed Suppression and Performance of Grain Legumes Following an Irrigated Rice Crop in Southern Australia

“…Similar estimates have been calculated for field pea [41], and in the present study, we estimate these values at 170, 135 and 75 kg·N·ha −1 fixed by S1, S2 and S3 field pea crops, respectively. These represent significant inputs to soil N that could be used by cereal crops following legumes as a rotation [18].…”

“…Hence, post-rice soils are not always suitable for immediate cultivation of aerobic crops following rice harvest [17]. However, it would be desirable to determine if a high value pulse crop could be grown following rice to improve profitability, weed management and soil properties for successive rotations and, hence, the sustainability of the cropping system [18]. Production of leguminous crops following rice offers numerous potential advantages, including more efficient use of irrigation water in contrast to post-fallow [19] and reduction of weed pressure [8,20].…”

Residue management strategies for the rainfed N-deprived maize-legume cropping systems of central Mozambique

“…In developed countries where simulation models are widely used, they have helped improve the understanding of crop eco-physiological responses and allowed researchers to answer basic questions, such as identifying the most suitable and remunerative cropping systems and patterns for different climatic and socioeconomic conditions (Cox et al, 2010;Meinke et al, 2001;Rodriguez et al, 2011). The use of crop and biophysical models capable of generating ex-ante information through the simulation of real world responses to factors such as the climate, soil and management (Bouma and Jones, 2001), has allowed researchers to provide farmers with timely and relevant advice that has helped shape local farming practices.…”

“…In Australia, for instance, the Agricultural Production Systems Simulator (APSIM) helped researchers identify the most suitable and remunerative cropping systems for different climatic and socio-economic contexts (Cox et al, 2010;Meinke et al, 2001;Rodriguez et al, 2011). Moreover, the integration of simulation modelling in research programs across the world have helped to (1) identify gaps in existing knowledge; (2) generate and test hypothesis to improve the design of experiments; (3) determine the most influential parameters of a system (Matthews and Stephens, 2002b); and (4) bring researchers, experiments and farmers together to discuss problems and identify solutions in participatory modelling exercises (Whitbread et al, 2010).…”