Effects Of Soil Fertility And Cultivation Pattern On Canopy Structure And Physiological Characteristics Of Summer Maize

This study was conducted from 2013 to 2014 in Dongwu village, Dawenkou Town, Shandong Province and State Key Laboratory of Crop Biology of Shandong Agricultural University. Zhengdan 958 was taken as the experimental material. We set high(HSF) and low(LSF) this two fertility conditions. And seven different treatment which were super high-yield treatment(SH), high yield and high fertilizers utilization rate treatment(HH), farmers’ practice treanment(FP), no fertilizer treatment(N0P0K0), no nitrogen fertilizer treatment(N0), no phosphate fertilizer treatment(P0) and no potash fertilizer treatment(K0) were set on each field. Then compared and analyzed the canopy structure and physiological characteristics of different soil fertilities and cultivation patterns. To find suitable fertilization measures and provide theoretical references for creating super high-yield, high yield and fertilizers utilization rate canopy structure on different soil fertilities. The results as follows:1. Effects on canopy structure of summer maize in different levels of soil fertility and modes of cultivation HSF compared to LSF, the plant height and tassel height of summer maize had increased, the stem diameter decreases and the basal second length shorten; Performance of LOV on HSF was upper layer>ear layer>lower layer while which on LSF had little difference. The growth rate of LAI before flowering was more higher on HSF, and fell faster after R4 stage. The high LAI duration of SH and HH were 54 d and 48 d on HSF while they were 56 d and 51 d on the LSF. FP and N0P0K0 could not reach the level of LAI≥5. From VT to R3 stage, the lower layer LAI of HSF fell more than LSF. Weight value of lower layer and ear layer had equal attention At R3 stage on HSF. And lower layer was more higher LAI weight value. It had little difference between HSF and LSF on LAD of whole growth stage, before and after VT. The transmission of ear layer and lower layer were higher on HSF than it on LSF at VT.SH and HH had a higher plant height, tassel height and shorter basal second length than FP. Stem diameter of SH and HH were more coarse than N0P0K0. SH and HH had a less leaf angle and bigger LOV at upper layer, while leaf angle and LOV were both less at ear layer and bigger leaf angle and less LOV at lower layer. The LAI was SH>HH>FP>N0P0K0 before R3. LAD of whole growth stage of SH was 34.4% and 42.6% more than FP and N0P0K0, HH was 35.6% and 43.9% more than FP、N0P0K0. Canopy light transmission of SH and HH at VT were significantly lower than FP and N0P0K0. The canopy light transmission of lower payer raised at R5, but SH and HH were still lower than FP and N0P0K0, HH was significantly lower than FP and N0P0K0. Nutrient-deficient treatment significantly affect the canopy structure of HH. The specific performance of different elements were N>P>K on HSF and N>K>P on LSF.2. Effects on photosynthetic characteristics of summer maize in different levels of soil fertility and modes of cultivation Chl.a and chl.b content had a faster increase and a slower decrease on HSF than LSF. Caro. content had a sustained increase on HSF while it had a less increasing range and decrease of SH, HH after R2. In VT and R3 stage, Pn was higher on HSF than LSF. Gs had a high speed of decrease from VT to R5. Fv/Fm was lower on LSF and difference between treatment and growth stage were small.With the growth of summer maize, q P increase first and then decrease except FP and N0P0K0 decrease all the whole growth stage. From VT to R3 stage and R3 to R5 stage, number of chloropladt per cell decreased by 16%, 13% on HSF and 11%, 4% on LSF. That of number of grana per chloropladt was 13%, 18% and 14%, 15%. And the number of grana lamellae per grana was 7%, 24% and 39%, 22%。 SH, HH, FP compared with N0P0K0, had significantly improved the photosynthetic pigments of summer maize on LSF. And so as the photosynthetic enzymes activity on both soil fertility. Pn of SH and HH were higher than FP and N0P0K0 on HSF. On LSF, Pn of HH was higher than others treatment and SH had little difference between with FP. The performance of Gs was the same as Pn. SH and HH had a lower Ci than FP and N0P0K0 on HSF. And Ci of SH, FP and N0P0K0 significantly higher than HH. In R3 stage, Fv/Fm of SH, HH, FP were significantly higher than N0P0K0, and SH, HH increased by 5.6%, 7.3%. NPQ of SH, HH, FP was increased by 18.2%, 18.3%, 7.3% on HSF and 25.2%, 36.9%, 18.4% on LSF compared with N0P0K0. To q P the results were 12.7%, 11.6%, 7.0% and 9.8%, 12.7%, 7.1%. The result of ΦPSⅡ was 20.3%, 17.4%, 21.6% on HSF and 11.9%, 22.3%, 12.7% on LSF from VT to R3 stage. N0 treatment significantly reduced the chl.a+b and caro. content, and so as the Ru BPCase, PEPCase activity. Pn of N0, P0, K0 treatments all decrease, while only Gs and Ci of P0 and K0 treatment increase. The Ci of N0 treatment decrease. Nutrient-deficient treatment significantly decreased the Fv/Fm. The N0, P0 and K0 reduced by 2.4%, 1.4% and 0.8%. q P finally manifested as N0<P0<K0<HH. The NPQ of N0 treatment improved by 12.9% and 36.7% on high and low soil fertility.3. Effects on senescence characteristics of summer maize in different levels of soil fertility and modes of cultivation SOD activity of summer maize on HSF was lower in early growth stage, and raised quickly in VT to R2. While it sustained increased from V9 stage on LSF. Those meant that summer maize had an earlier aging on LSF than HSF. The leaf of summer maize on HSF had a higher SOD activity in later growth stage. So it had a storger scavenging ability on superoxide anion.POD activity had a bigger difference on LSF than HSF. The modes of cultivation affected less to POD activity with the growth of soil fertility. The summer maize had a lower MDA content and later time of highest value appear than it on LSF. It also lower on the speed of rising period. SH and HH had a high SOD activity than FP and N0P0K0 in VT to R4. POD activity of whole growth stage was HH>SH>FP>N0P0K0. SH and HH had a little difference between FP, but significantly higher than N0P0K0. N0P0K0 had the highest MDA content on all soil fertility and modes of cultivation, then was FP, SH and HH had a low content. SH and HH modes of cultivation raised the activity of protective enzyme system of summer maize, depressed the produce of MDA and then kept the cell had a integral cell membrance system. SOD activity of N0 on HSF and N0, K0 on LSF were significantly lower than HH. N0 had a low POD and CAT activity on both soil fertility. And then was K0. P0 had little difference with HH. The MDA content was N0>K0>P0.4. Effects on grain yield and yield components of summer maize in different levels of soil fertility and modes of cultivation The grain yield of summer maize on HSF was 5.81% more than it on LSF. SH, HH, FP had increased separately20.59%, 30.50%, 34.34% and 29.69%, 40.40%, 45.87% than N0P0K0 on HSF and LSF. The range of increase on LSF was bigger than it on HSF. Appropriate increase the fertilizer inputs and split application could increase the grain yield and improve the yield-increasing potential. The grain yield between different modes were SH>HH>FP>N0P0K0. HH and SH increased by 8.24% and 11.93 than FP. But the grain number per spike and 1000-kernelsweight of FP was bigger than SH and HH. It illustrated that the increasing of plant density could direct and efficient improve the grain yield of summer maize. N0, P0, K0 reduced the grain number per spike and 1000-kernelsweight of HH. And the grain yield had also reduced by 14.76%, 3.59%, 3.90% and 22.11%, 7.39%, 7.41% in two years. Nitrogen fertilizer had the most impact on grain yield and yield components of summer maize. NPK fertilizer cooperating application was an important conditions for summer maize to get a high grain yield.