Soil water cycle and crop water use efficiency after long-term nitrogen fertilization in Loess Plateau

Abstract

The objective of this study was to investigate the effect of nitrogen (N) management on soil water recharge, available soil water at sowing (ASWS), soil water depletion, and wheat (Triticum aestivum L.) yield and water use efficiency (WUE) after long-term fertilization. We collected data from 2 experiments in 2 growing seasons. Treatments varied from no fertilization (CK), single N or phosphorus (P), N and P (NP), to NP plus manure (NPM). Comparing to CK and single N or P treatments, NP and NPM reduced rainfall infiltration depth by 20–60 cm, increased water recharge by 16–21 mm, and decreased ASWS by 89–133 mm in 0–300 cm profile. However, crop yield and WUE continuously increased in NP and NPM treatments after 22 years of fertilization. Yield ranged from 3458 to 3782 kg/ha in NP or NPM but was 1246–1531 kg/ha in CK and single N or P. WUE in CK and single N or P treatments was < 6 kg/ha/mm but increased to 12.1 kg/ha/mm in a NP treatment. The NP and NPM fertilization provided benefits for increased yield and WUE but resulted in lower ASWS. Increasing ASWS may be important for sustainable yield after long-term fertilization.

Soil Moisture Response to Short-Term Inorganic Fertilization on Tef (Eragrostis tef (Zucc.) Trotter) Crop Varieties in Northern Ethiopia

“…In agreement to the present results, previous researchers (e.g., [18,19]) using long-term fertilizer trials have reported that soil water demand of crops varied with growth stages, and crop water demand decreased towards the end of the growing season. In addition, consistent with the present finding that soil moisture decreases when fertilizer rate increases, reports from elsewhere have shown that adequate nutrient supply can contribute to increasing water and nutrient uptake (more water used) by plants from the soil, thereby decreasing available soil moisture for producing better crop growth [20,21].…”

“…Positive values of mean differences in SMC between the cropping seasons indicate that SMC was higher in 2012 on average by 12% as compared to the 2013 cropping season due to the combined effects of N + P fertilizer rates with tef crop varieties (Tables 4 and 5). is finding is consistent with the previous reports (e.g., [19,23,24]) who have reported that increasing fertilizer application for consecutive years causes depletion of soil water. ere were significant paired mean differences in SMC among most treatments between the same sampling date (growth stage) in the two cropping seasons (Table 7), indicating that the short-term effects of the treatments on SMC across the years are well noticed.…”

“…In addition, consistent with the present finding that soil moisture decreases when fertilizer rate increases, reports from elsewhere have shown that adequate nutrient supply can contribute to increasing water and nutrient uptake (more water used) by plants from the soil, thereby decreasing available soil moisture for producing better crop growth [20,21]. Previous reports have also stated that available soil moisture could be reduced by long-term N and P fertilization as this considerably increases crop water use for transpiration which resulted in a decrease in soil moisture within a soil profile [19,[22][23][24]. However, such reports have not evaluated SMC from the context of the short-term effects of fertilization on crop varieties in which this was addressed by the present research.…”

“…e implication is that when fertilizer rates increased, there is high soil water depletion by the plant for being nutrients available regardless of the type of variety [18,19,[22][23][24]. Other researchers have reported that the successive use of chemical fertilizers leads to the deterioration of soil quality due to effects on nutrient imbalances [25,26].…”

Ecological problems and nitrogen balance in vegetable crops growing

“…an increase the productivity of the crops and often remain unused in agroecosystems (Stoicheva et al, 2011). The fertilizers which are not included in the biological cycle of substances are potential a source of negative changes in the solid and liquid phase of the soil (Bordoloi et al, 2013;Wang et al, 2013). The exceedance of nitrogen standards as regards the fertilization application can lead to nitrogen losses, especially in the form of nitrates, which passing through the soil profile (Addiscott, 1996, Alexandrova et al, 2001Koleva et Stoicheva, 2008;Stoicheva et al, 2003;Smith at al., 2003) are cause pollution of surface and groundwater.…”