The mechanism of different combinations of organic and N, P fertilizers increasing yield of dryland wheat

Objectives Combined application of organic and inorganic fertilizer can provide enough nutrient to crops to increase production. In order to dig into yield potential in dryland wheat, effects of combined application of organic and N, P fertilizers on yield increasing and mechanism of hilly dryland wheat were studied in Linfen City, Shanxi Province from 2012 to 2014.

Methods A randomized block design with a split plot experiment was laid out and three kinds of organic fertilizer, 22.5 t/hm² of pig manure (M_P), 22.5 t/hm² of sheep manure (M_S) and 2.25 t/hm² of refined organic fertilizer (M_O), were used as the main plot factors. Four N, P fertilizers rates were set as sub plots:N₀P₀, N₁₀₅P₇₅, N₁₅₀P₁₀₅, and CK. The SPAD value of flag leaf, grain-filling characteristics, dry matter accumulation and yield of the Jinmai 92 were tested.

Results The SPAD value of organic and N, P fertilizers decreased slowly in the late sage of seed filling. The SPAD value and average rate of the middle stage of filling was the highest in single pig manure. The SPAD value of the late stage of filling, grain filling duration, stem leaf transferring and amount of spike were the highest in single refined organic fertilizer. The SPAD value, grain filling duration, dry matter accumulation were improved in M_SN₁₅₀P₁₀₅, M_PN₁₀₅P₇₅and M_ON₁₀₅P₇₅. The number of ears, 1000-grain weight and yield of organic and N, P fertilizers were higher than those single organic fertilizer. The yield of M_SN₁₅₀P₁₀₅was the highest and had no significant difference with M_PN₁₀₅P₇₅.

Conclusion Organic fertilizer with a suitable amount of chemical fertilizer, increase panicles, and could improve the photosynthetic characteristics, extend the filling duration, increase grain production in hilly dryland of Shanxi, yield increasing effect was the bestin 22.5 t/hm² of sheep manure combining N 150 kg/hm² and P₂O₅105 kg/hm², 22.5 t/hm² of pig manure combining N 105 kg/hm² and P₂O₅75 kg/hm² could reduce fertilizer application and increase production.