Use of intercropping and mulch to improve the water and natural resources use efficiencies of forage cactus and millet production in a semiarid region

1. CONTEXT - Improving the use of natural resources (e.g., water, nutrients, and radiation) within production systems under different technologies (mulch and intercropping) is fundamental to intensifying sustainable agriculture. 2. OBJECTIVE - The objective was to quantify the parameters of water consumption and the efficiency of using natural resources of forage cactus and millet under different technologies of crops in a semiarid environment. 3. METHODS - The forage cactus (clone Orelha de Elefante Mexicana) and millet (cv. IPA Bulk-1BF) were evaluated to six cropping arrangements: single cactus with mulch (CWM), single cactus with no mulch (CNM), single millet with mulch (MWM), single millet with no mulch (MNM), a cactus-millet intercropping system with mulch (CMWM), and cactus-millet intercropping system with no mulch (CMNM). Data on crop growth, crop production, and soil moisture were collected, and the following were determined: crop evapotranspiration (ETc), crop transpiration (T), soil water evaporation (E), single crop coefficient (Kc), dual crop coefficient (Kcb and Ke), water use efficiency (WUE), nutrient use efficiency (NUE) and radiation use efficiency (RUE). Biological efficiency and competitive ability indicators were calculated for the intercropped systems. 4. RESULTS AND CONCLUSIONS - The ETc (mm day -1) was higher under MWM (4.69), MNM (3.60), and CMWM (3.81). There was little variation in the values of ETc, T, or E between CNM and CWM, unlike between MNM and MWM. Intercropping reduced E compared to the single crops of cactus (8%) and millet (58%). On average, Kc was higher under MWM (0.98), CWM (0.69), and CMWM, (0.88), compared to MNM (0.75), CNM (0.63), and CMNM (0.48). The intercrops were more efficient for WUE (44%) and RUE (2.28 g MJ -1), with no difference for NUE. It can be concluded that the cactus-millet intercropping system is a good alternative for more-resilient agriculture in semi-arid environments, especially when the use of mulch. 5. SIGNIFICANCE - The results of this study are significant for the management of water resources in the semi-arid region, as they favour knowledge of the water needs of these crops in different production systems, and how the adoption of technologies such as intercropping and mulching can improve efficiency in the use of available natural resources, compared to exclusive planting.