Research on the Production Efficiency and Utilizing Rate of Potassium Fertilizer for Rape in Yunnan Province

[Objective] This study aimed at investigating the effects of consumption of potassium fertilizer on production and biological characteristics of rape and utilizing efficiency of potassium fertilizer.[Method] Taking 0 kg/hm2 as control,nine consumptions of potassium fertilizer were designed for the experiment using single factor randomized block design with three replications and field experiment in nine rape-producing areas with different ecological types in Yunnan Province.[Result] Appropriately applying potassium fertilizer in Yunnan Province could improve the rapeseed production,the rape production could achieve 3 983-4 151 kg when applied 150-180 kg/hm2 of K2O,which had increased by 4.7-9.1% compared with the control and attained the peak in K165 treatment.When applied 1 kg of K2O,the rapeseed production could enhance 559 kg,the net profit could reach 1 229 yuan/hm2 and the partial productivity of potassium fertilizer could attain 31.32 kg/kg K2O and 3.7 kg/kg K2O,respectively.Applying potassium fertilizer could promote the growth of rape and increase rapeseed production.[Conclusion] The recommended optimal consumptions of potassium fertilizer with high production and high efficiency for rape in Yunnan Province were ranged between 150 and 180 kg K2O/hm2.However,comprehensively considering production and efficiency factors,the consumption of potassium fertilizer in Yunnan Province was around 73.9 kg/hm2,which should be appropriately increased to around 100.0 kg/hm2 in Longchuan,Yulong,Linxiang and other producing areas with similar conditions.

Effects of Main Cultivation Factors on Rapeseed Oil Yield

[Objective] This study aimed to analyze the influence of six cultivation fac- tors： sowing date, plant density, nitrogen fertilizer amount, phosphate fertilizer amount, potash fertilizer amount and boron fertilizer amount on seed oil yield of Brassica napus. [Method] Statistical analysis was carried out based on the data from previous studies and our work. [Result] Oil yield shared a negative correlation with sowing date, a parabolic relationship with plant density mostly, parabolic rela- tionships with amount of applied nitrogen fertilizer and amount of applied boron fer- tilizer, straight-line relationships with amount of applied phosphate fertilizer and amount of applied potash fertilizer. The average amount of applied nitrogen fertilizer required to obtain the highest oil yield was 185.18 kg/hm2 for high-oil rape varieties （with oil content above 44.00%）, and under this condition, the average oil yield of low-oil rape varieties （with oil content below 42.00%） was 1 247.84 kg/hm2, while that of high-oil rape varieties was 1 442.60 kg/hm2, which was 15.61% more than the former. The average amount of applied nitrogen fertilizer required to obtain the highest oil yield for lower-oil rape varieties was 286.28 kg/hm2, and under this con- dition, the average oil yield of the low-oil rape varieties was 1 350.57 kg/hm2, while that of the high-oil varieties was 6.81% higher than it. There was a significant neg- ative correlation between rapeseed oil yield and the amount of applied nitrogen fer- tilizer to obtain the highest oil yield （0.980 0）. The optimum amount of applied ni- trogen, phosphate, potash and boron fertilizer were 187.5-195, 187.5-195, 105-120, 135-150 and 15-22.5 kg/hm2 for high-oil B. napus varieties. [Conclusion] This study determined the influence of sowing date, plant density and amount of applied nitro- gen fertilizer on oil yield of B. napus, and proposed an optimum cultivation pattern for high-oil varieties.

Effects of Interaction between Density and Nitrogen Rate on Growth and Yield of No-tilling and Direct Sowing Rapeseed in Chengdu Plain

[Objective] The aim was to explore the optimal density and nitrogen rate of no-tilling and direct sowing rapeseeds in Chengdu plain. [Methods] Effects of in- teraction between density and nitrogen rate on the growth and yield of direct sowing rapeseed under no-tillage condition were investigated with Chuanyou 58 as materials and a split-plot experiment adopted. [Results] In Chengdu Plain, the yields of rape- seed changed from increasing to decreasing with increase of density and nitrogen rate. Both of density and nitrogen rate had significant effects on growth and yield of rapeseed and the latter overweighed in the effect. In addition, interaction of the two had negative effects on rapeseed yield. The yield of rapeseeds achieved the highest at 3 395.25 kg/hm^2 with interaction of density at 30.00×10^4 plant/hm^2 and nitrogen rate at 180.00 kg/hm^2; the theoretical maximal yield was 3 403.41 kg/hm^2 with interaction of density at 40.80×10^4 plants/hm^2 and nitrogen rate at 198.90 kg/hm^2. [Conclusion] In Chengdu Plain, the optimal density and nitrogen rate are 30.00×10^4-45.00×10^4 plant/hm^2 and 180.00-198.90 kg/hm^2, respectively.

Effects of Different Irrigation Amounts on Water Consumption and Water Use Efficiency of Dripirrigated Celery

This study aimed to investigate the effects of different irrigation amounts on water consumption and water use efficiency of celery under the condition of drip irrigation, so as to provide a scientific basis for high-yielding, high-quality and highefficiency cultivation and water-saving irrigation of greenhouse celery. Total five irrigation amounts were designed, 117.5 （T1）, 160.0 （T2）, 202.5 （T3）, 245.0 （T4） and 287.5 （CK） mm/hm2, and the effects of different irrigation amounts on yield, water consumption and water use efficiency of celery were studied by plot experiment. The results showed that at the soil depth of 0-40 cm, the soil water storages of different treatments ranked as T3＇s〉T4＇s〉CK＇s〉T2＇s〉T1＇s, and the celery water consumptions ranked as CK＇s〉T4＇s〉T3＇s〉T2＇s〉T1＇s. At the same time, the soil water storage in different treatment group declined with the growth of celery, and finally increased at the harvest period. Among different irrigation amounts, the water use effi- ciency and irrigation water use efficiency all ranked as T1＇s〉T2＇s〉T3＇s〉T4＇s〉CK＇s. The water consumption of celery was positively related to irrigation amount （P〈 0.01）, and was negatively related to water use efficiency （P〈0.01） and irrigation water use efficiency （P〈0.05）. When the irrigation amount was below 253 mm/hm2, the celery yield was positively related to irrigation amount （P〈0.01）. There was also a positive correlation between celery output and irrigation amount. Compared with those of CK, the benefit of the T4 treatment group was equal, and the water consumption was reduced by 14.78%. In high-efficiency solar greenhouse, the irrigation amount of drip-irrigated celery is recommended as 245 mm/hm2.

Comparions of Required Nitrogen Fertilizers by Hybrid Cultivar and Conventional Cultivar of Rapeseed(Brassica napus L.)

[Objective] The aim of this study was to understand the difference of N fertilizer requirement between hybrid rapeseed and conventional rapeseed. [Method] Two hybrid cultivars, ZY5628 and ZY7819, and the conventional cultivar ZS10, were compared through two field experiments. In Experiment 1, seed yield and optimum N application rate were assessed in the field with five N application treatments. In Expedment 2, N was applied uniformly at 180 kg/hm2, and plant biomass and N accumulation were measured at several developmental stages, while N use efficien- cy was calculated for rape at maturity. [Results] The experiment 1 results showed that seed yields of ZY5628 and ZY7819 were both significantly higher than that of ZS10, and compared to ZS10, optimum yield （plateau yield） was higher by 18.7% and 20.2%, while the recommended N application rate was lower by 9.5% and 9.6% for ZY5628 and ZY7819, respectively. The experiment 2 results showed that during vegetative development, all three cultivars exhibited similar accumulations of plant biomass and N, but through flowering and maturity ZY5628 and ZY7819 pro- duced more biomass, acquired more N, and utilized acquired N more efficiently to- wards seed production than ZS10. [Conclusion] With equivalent inputs, the hybrid rapeseed cultivars ZY5628 and ZY7819 tested herein yield more seed with higher N use efficiency than the conventional rapeseed ZS10. This information will be valu- able for growers seeking to improve efficiency while reducing costs of rape production in China.

^(15)N Isotope Techniques for Estimating Effects of Urea-N Fertilizer Application Rate on Yields and Nutrient Contents of Pakchoi Cabbage and Asparagus Lettuce and Nitrogen Utilization Efficiency

A pot experiment combined with15N isotope techniques was conducted to evaluate effects of the varying rates of urea-N fertilizer application on yields,quality,and nitrogen use efficiency (NUE) of pakchoi cabbage (Brassica chinensis L.) and asparagus lettuce (Lactuca saiva L.).15N-labbled urea (5.3515N atom %) was added to pots with 6.5 kg soil of 0.14,0.18,0.21,0.25,and 0.29 g N/kg soil,and applied in two splits:60 percent as basal dressing in the mixture and 40 percent as topdressing.The fresh yields of two vegetable species increased with the increasing input of urea-N,but there was a significant quadratic relationship between the dose of urea-N fertilizer application and the fresh yields.When the dosage of urea-N fertilizer reached a certain value,nitrate readily accumulated in the two kinds of plants due to the decrease in NR activity; furthermore,there was a linear negative correlation between nitrate content and NR activity.With the increasing input of urea-N,ascorbic acid and soluble sugar initially increased,declined after a while,and crude fiber rapidly decreased too.Total absorbed N (TAN),N derived from fertilizer (Ndff),and N derived from soil (Ndfs) increased,and the ratio of Ndff and TAN also increased,but the ratio of Ndfs and TAN as well as NUE of urea-N fertilizer decreased with the increasing input of urea-N.These results suggested that the increasing application of labeled N fertilizer led to the increase in unlabeled N (namely,Ndfs) presumably due to "added nitrogen interaction" (ANI),the decease in NUE of urea-N fertilizer may be due to excess fertilization beyond the levels of plant requirements and the ANI,and the decrease in the two vegetable yields with the increasing addition of urea-N possibly because the excess accumulation of nitrate reached a toxic level.

Influence of Different Plant Materials in Combination with Chicken Manure on Soil Carbon and Nitrogen Contents and Vegetable Yield

The use of plant materials as soil amendments is an uncommon practice amongst major farming communities in Ghana, although it is necessary for soil fertility improvement. An examination of the effects of soil amendments is necessary to encourage the use of under-utilized organic resources in Ghana. Thus, a field experiment was conducted using 8 different tropical plant materials mixed with chicken manure as soil amendments for growth of tomato as a test crop. The plant materials included Leucaena leueocephala, Centrosema pubescens, Sesbania sesban, Gliricidia sepium, Mucuna pruriens, Pueraria phaseoloides, Azadirachta indiea, and Theo- broma cacao. There were two other treatments： one with equivalent amounts of chemical fertilizers and the other with no-fertilizer input （control）. Plant materials were mixed with chicken manure to obtain a uniform carbon-to-nitrogen （C：N） ratio of 5：1. Except the no-fertilizer control, all treatments received the same amount of nitrogen （N）. To clarify the decomposition pattern of the plant materials in soil, an incubation experiment was conducted using only the plant materials before the field experiment. The Glirieidia treatment released significantly more mineral N than the other plant materials in the incubation experiment. However, the tomato fruit yield was not enhanced in the Gliricidia treatment in the field experiment. The known quality parameters of the tested plant materials, such as total N, total carbon （C）, C：N ratio, and total polyphenols, had minimal effects on their mineralization dynamics. Azadirachta showed the best synergistic effect with chicken manure through significantly increasing soil microbial biomass and fruit yield of tomato. This result provides insights into the possible adoption of Azadirachta in combination with chicken manure as a soil amendment in small-scale agricultural holdings.