Soil phosphorus accumulation model for an arid area of north-western China with 3-year rotation of wheat, maize and cotton

Abstract

Predictive models for the accumulation of available phosphorus (Olsen-P, extracted with 0·5 mol/l sodium bicarbonate (NaHCO 3 ) at pH 8·5) in the north-western arid areas of China, especially in Xinjiang, are essential for the improved management of phosphorus (P) fertilizers. In the present study, an accumulation model for Olsen-P in grey desert soil (Calcaric Cambisol) was developed using the data for initial Olsen-P in soil, P fertilizer application rate (organic and inorganic P), crop yields, and soil pH from a 22-year long-term experiment (1990-2011) with 3-year rotation of wheat (Triticum aestivum L.), maize (Zea mays L.) and cotton (Gossypium spp.). The model was also validated independently using previously published data from the literature. The results indicated an average net accumulation of Olsen-P in the plough layer (0-200 mm) of 0·36 mg/kg/year (from 0·083 to 0·47 mg/kg/year) when P fertilizer was applied, while an average net Olsen-P loss of 0·12 mg/kg/year (from 0·067 to 0·26 mg/kg/ year) was observed without P fertilization in the soil. For target yields of wheat, maize and cotton at 5, 6 and 6 tonne/ha (t/ha), respectively, in soil with pH 8, the rates of Olsen-P increase in the soil as estimated by the model were 0·11, 0·24, 0·36, 0·49 and 0·61 mg/kg/year when P application rates were 60, 70, 80, 90 and 100 kg P/ha per 3-year period, respectively. For every 100 kg/ha of P surplus, Olsen-P increased by 1·1 mg/kg in Xinjiang grey desert soil. This Olsen-P accumulation model was valuable for the management of soil P in agricultural production and environmental protection in north-western China and other arid areas planted with a yearly rotation of wheat, maize or cotton.

Diversity and Abundance of Soil Animals as Influenced by Long-Term Fertilization in Grey Desert Soil, China

“…The experimental site (43°58′ N, 87°25′ E, 600 m a.s.l.) was located in the suburbs of Urumqi, Xinjiang, China, and has a typical continental arid climate [15]. The study site is typical oasis farmland with a maize-wheat-cotton crop rotation in order to keep the soil quality not affected by the crops.…”

“…The experimental plot covered an area of 468 m 2 and crop yields were determined from the whole plot area. The long-term experiment was conducted during 1990-2014 [15]. …”

“…The fact that the changes in the crop yields makes them sustainable to obtain the response of soil fauna to fertilization regimes. Belonging to weathered soils, they are typically managed with little external input, which contributes to nutrient-poor soils under a typical continental arid climate [15]. However, they are important agricultural soils in northwestern China, because as much as 52,528 square kilometers of grey desert soils are cultivated agricultural land across China and more than a quarter is in Xinjiang [16].…”

Modeling of Phosphorus Nutrition to Obtain Maximum Yield, High P Use Efficiency and Low P-Loss Risk for Wheat Grown in Sandy Calcareous Soils

“…Under P deficient conditions, the application of P fertilizers is required to increase the availability of P to target levels, depending on soil properties [1,10]. During the last century, the rates of P application have been increased to raise the availability of P in soil, but raising availability of P in soils also increases the loss of P through run off, leaching, and erosion, causing water eutrophication [15,16]. Besides, the amount of rock phosphate for P manufacturing is limited, thus, management of P fertilization in a careful manner is mandatory [17][18][19].…”

“…The critical value of soil P for potential yield of crop plants, which varies according to soil type, crop species, and environmental factors, is defined as the content of P in the soil above which an increase in potential yield is not expected [12,21,22]. To attain potential yields, farmers tend to apply excess amounts of P fertilizers beyond recommended doses leading to accumulation of P in the topsoil of farmlands and the formation of a large P pool [15,16]. The minimum level of available soil P for maximum crop production is referred to as the agronomically critical value of the available soil P which is the available soil P content used by researchers as a criterion for P fertilizing [12,21,23].…”