| Effects of P rates on N P K and dry matter accumulation and grain yield of winter wheat |
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| DOI：10.7606/j.issn.1000-7601.2011.01.21 |
| Key Words: P rates winter wheat yield water nitrogen phosphorus potassium |
| Author Name | Affiliation | | WANG Ronghui | College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China
Soil and Fertilizer Research Institute, Guangdong Academy of Agri. Sciences, Guangzhou, Guangdong 510640, China | | WANG Zhaohui | College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China | | LI Shengxiu | College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China | | WANG Xina | College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China | | LI Hua | College of Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China |
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| Abstract: |
| In order to explain the phenomenon of the decrease
of crop yield-increasing effects caused by over fertilizer application commonly existing in present agricultural production in China, this paper focused on the effects of P rates on N, P, K and dry matter accumulation and grain yield of winter wheat. A field experiment was carried out with winter wheat as test crop and at P rates of 0, 50 (deficient), 100 (optimum) and 150 (excessive) P2O5 kg/hm2. The aboveground part of the crop was sampled at different stages to estimate the crop biomass and to determine the content of water, N, P and K in different plant parts. Furthermore, the relationship between grain yield and biomass accumulation, water and nutrient uptake in the plant was discussed. The obtained results showed that no significant difference was found for the harvest indexes over different P rates. One of the main reasons for the increase of grain yield caused by optimum P rates was owing to the increased biomass accumulation, but not the increased translocation of dry matter from vegetative part to grain at late growth stages. Excessive P application was observed to increase dry matter losses during late growth stages at 8 364 kg/hm2, which accounted for 39% of m
aximum biomass accumulation and was 22% higher than that at optimum P application. The water accumulation rate at rejoining stage was 989 kg/(hm2·d) at optimum P rates, while is 902 kg/(hm2·d) at excessive P rate. However, water lo
ss was 86% of maximum water accumulation at excessive P rates, which was 82% at optimum P rates during the late growth stages. Application of P promoted nutrient uptake at early growth stages, but also increased the nutrient losses at late growth stages with the increase of P rates. Compared to the maximum nutrient accumulation, the losses were 26% and 34% for N, 2% and 13% for P, and 26% and 34% for K, respectively at optimum and excessive P application. Excessive P application could not only decrease water accumulation at early growth stages, but also increase the losses of biomass, water, N, P and K at the late growing stages, and therefore led to a decrease of grain yield of winter wheat. |
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