Effects Of Fertilization On Quality Of Pennisetum As Energy Plant

The energy crisis has become the great challenge to the world. Seeking for new sustainable resources has become a major issue to our country. Pennisetum is perennial herb as C4-type plant with high photosynthetic capacity and rich carbohydrate, so it can be used to a potential bio-energy plant.This article aimed to study the effect of Nitrogen (N), Phosphorus (P) and Potassium (K) fertilizer on the quality of Pennisetum (S9) in the condition of pot experiment, probing into the relation between different N, P, K application levels and sugar, lignocellulose of Pennisetum, and find out the best fertilizer application amount, which can improve the quality of Pennisetum as energy plant, providing scientific basis for its application. The results showed as follows:1. N, P fertilizer application can promote significantly biomass and the agronomic characters of Pennisetum, whereas K fertilizer was not obvious. N, P fertilizer can increase significantly general biomass of Pennisetum with no obvious effect from K fertilizer. The general, stem and leaf biomass all increased and then decreased with increasing N fertilizer application. The general, stem and leaf biomass of Pennisetum all reached the maximum with59.57g/pot,33.07g/pot and26.50g/pot, respectively. When N application amount reached to150kg/hm2, the yield-increasing rate comparing with the control group (NO) were73.32%,77.13%and68.79%, respectively. The general and stem biomass increased gradually, and leaf biomass increased and then decreased with P application levels increased. When P application amount was60kg/hm2, leaf biomass reached the maximum with26.13g/pot, the yield-increasing rate of general, stem and leaf biomass were11.69%～123.87%,9.58%～146.85%and107.71%, respectively. K fertilizer application showed no significant effect on biomass of Pennisetum with the level of0-80kg/hm2.2. N, P fertilizer can promote significantly the SPAD values of Pennisetum. The SPAD values gradually increased with N, P application levels increased after transplanting for80days, whereas K fertilizer were not obvious.3. N, P fertilizer can promote significantly the reducing sugar and total sugar content of Pennisetum, and promote sucrose content to some extent, whereas K fertilizer was not obvious. The reducing sugar and total sugar content all increased and then decreased with N, P application levels increased, but they showed no remarkable trend in different K fertilizer application. When N application levels was150kg/hm2(N3), the reducing sugar and total sugar content in stems, leaves and the whole plant of Pennisetum all reached the maximum,11.5%and15.3%for reducing sugar, total sugar in the whole plant,16.2%and21.3%for reducing sugar, total sugar in stem,6.5%and9.1%for reducing sugar, total sugar in leaf, respectively. When P application levels was40kg/hm2(P2), the content of whole plant,stem and leaf all reached maximum,12.2%and16.2%for reducing sugar, total sugar in the whole plant,16.9%and22.3%for reducing sugar, total sugar in stem,6.5%and8.6%for reducing sugar, total sugar in leaf, respectively. Sugar content of Pennisetum stem was higher than leaf and whole plant.4. N fertilizer had negative effect on cellulose, lignin and ash content of the whole plant, stem, leaf of Pennisetum, but it could promote hemicellulose. P fertilizer can promote cellulose, hemicellulose and lignin content of the leaf. P fertilizer can also promote cellulose, lignin and ash of the stem, but it could inhibit hemicellulose. K fertilizer application showed no significant effect on lignocellulose content of Pennisetum. Lignin content of the stem was significantly higher than leaf, ash content of the stems was significantly lower than leaf. When N application levels was in100～150kg/hm2, the effect on lignocellulose is better, the same as P application levels in40～60kg/hm2.