Temporal and spatial distribution of soil water and nitrate content affected by surface irrigation and fertilizer rate in silage corn fields

Abstract

Among surface irrigation systems, long border and furrow are more adaptive to mechanized farming but may cause a non-uniform distribution of water and nutrients. In this study, field experiments were carried out in a flat silage corn field in Hebei, China to investigate the uniformity along the length of border or furrow to understand the spatial and temporal distribution characteristics of soil water, electrical conductivity, and nitrate. This will guide irrigation and fertigation management recommendations, land consolidation, and high standard farmland construction. Border and furrow irrigation were tested using fertilizer rates of 750, 600, 450 and 300 kg/ha. Low quarter distribution uniformity (DU lq) and storage efficiency (E) were quantified to determine the distribution of soil water and soil nitrate content. The results indicate heterogeneity along the length of the border or furrow is weak for soil water content and is moderate for nitrate content, based on the uniformity coefficient (CV). The average low quarter distribution uniformity of soil water (DU lqW) was 96.34, there was a significant effect of irrigation type on DU lqW , and the DU lqW for border irrigation was 0.8% larger than that for furrow irrigation. The average low quarter distribution uniformity of nitrate content DU lqN was 79.04, and there was no significant influence of irrigation type and fertilizer rate on DU lqN. Spatial and temporal distribution analysis showed that the variation of soil water in the 0-60 cm soil layer was larger than that in 60-100 cm soil layer, and the electrical conductivity (EC) and nitrate content gradually decreased with increasing soil depth. There was a decreasing trend in soil EC and nitrate content with decreasing fertilizer rates. The storage efficiency of water (E W) for border irrigation was 56.63, and significantly lower than that for furrow irrigation over the whole growth duration. The nitrate storage efficiency (E n) was 65.47, and there was no significant effect of irrigation type or fertilizer rate on E n. Even with longer borders or furrows of 90 m, the uniformity of water and nitrate along the length of the border or furrow is weak or medium, which can create non-uniform conditions for crop growth. Furrow irrigation may store slightly more water in the top 60 cm of soil compared to border irrigation. Fertilizer rate had no significant effect on the uniformity and distribution of soil water or nitrate. According to the statistics of the Food and Agricultural Organization of the United Nations, globally around 86% of the area equipped for full control irrigation is surface irrigation. Surface irrigation adapts well to most crops, low to medium soil infiltration characteristics and crop mechanization as well as environmental conditions 1. Surface irrigation delivers water to crops using a gravity-fed, overland flow of water, which may result in non-uniform distribution of water, excessive percolation losses near the outlet due to more infiltration opportunity time, some areas remaining under-wa...

Assessment of farmers' water and fertilizer practices and perceptions in the North China Plain

“…Regardless of whether the urea was spread onto the soil surface uniformly or nonuniformly, once irrigation waters entered the field, the particles flowed with the water from the head to the bottom end of the border, especially when the inflow rate was high. This points to a risk of leaching at the end of the border, especially on long borders where substantial quantities of water accumulate at the end (Cui et al, 2006; Liu, Wang, et al, 2020).…”

“…The use of fertigation can lower production costs while bringing opportunities for improved crop yields (Kabirigi et al, 2017). As surface irrigation is the dominant practice in most irrigated areas (Liu, Wang, et al, 2020; Siebert et al, 2005), many efforts have been made to promote pressurized irrigation in the fields (Gupta et al, 2021; Lecina et al, 2010; Yao et al, 2017).…”

Irrigation Decision Support Systems (IDSS) for California’s Water–Nutrient–Energy Nexus

“…Distribution uniformity can be defined as the even distribution or spread of applied irrigation to avoid over-or under-watering at specific locations across the field. Non-uniform distribution can not only reduce the yield, but it affects the drainage, increases soil erosion risk through runoff, increases nitrate leaching and reduces the available nitrate content in the soil [172,173]. Under California's arid conditions, a reduced use of water and energy in the agricultural sector is largely dependent on efficient DU.…”