Impacts of selected management practices on soil quality in an irrigated arid agroecosystem

Abstract

Understanding the impacts of cropping systems is crucial for agricultural sustainability. A study was conducted at New Mexico State University Agriculture Science Center at Los Lunas, New Mexico, United States, to investigate the effect of crop management practices on selected soil measurements. Four management systems on medium- to fine-textured surface soil, and two other management systems on coarse-textured surface soil were assessed. Management systems within the medium- to fine-textured soils included tall fescue (Lolium arundinaceum [Schreb.]) permanent grass fields (TFC), peach (Prunus persica [L.] Batsch) orchards with white clover (Trifolium repens L.) ground cover (PCC), alfalfa (Medicago sativa L.; ALF), and conventionally tilled land with annual crop rotations (CTC). The two systems studied in the coarse-textured soils were conventionally tilled soil with annual crop rotation (CTS) and young cottonwood tree (Populus deltoides W. Bartram) orchards (CWS). Soil samples were collected in three fields for each of the management systems at 0 to 15 and 15 to 30 cm. Twelve out of the 16 soil measurements assessed in the upper depth varied significantly with management system, while 10 out of the 16 measurements were significantly affected at the lower depth. With regard to agricultural productivity, management systems with permanent ground covers (TFC, PCC, and ALF) had more favorable soil characteristics compared to the conventionally tilled systems (CTC and CTS) or the system with no ground cover (CWS), while the management systems in medium- to fine-textured soils (TFC, PCC, ALF, and CTC) had more favorable soil characteristics than the coarse-textured soils (CTS and CWS). At the upper depth, the soil organic matter, a leading indicator of soil quality, was higher in the TFC (29.20 g kg⁻¹) and PCC (21.30 g kg⁻¹), both having permanent cover, than in the CTC (8.63 g kg⁻¹), CWS (6.36 g kg⁻¹), and CTS (8.30 g kg⁻¹). Soil nutrients were generally higher in the PCC and ALF, which had leguminous crops, indicating the beneficial effects of legumes in nutrient cycling of arid soils. Importantly, management impact on most soil characteristics was similar across both depths, indicating that sampling at 0 to 15 cm alone may be sufficient for evaluating the impacts of crop management systems on soil quality. This study shows that management systems, soil, and crop types are factors that need to be considered for sustainable management of soil quality in arid agroecosystems.