Sugarcane Straw Removal Enhances Short-Term N Source and N Source Efficiencies Under Sandy Soil Condition
摘要
The objectives of this study are to assess the effects of sugarcane straw removal with fertilizer application on (i) N source (soil mineral N, SOM lability (microbial biomass C and N)) and N source efficiency and (ii) the sugarcane straw decomposition. The field experiment used a randomized complete block design (RCBD) with three replications based on micro-plot size 1 m2 and litter bag study (32 weeks) at Khon Kaen University in a Yasothon sandy soil. A sugarcane straw dry weight (DW) of 6.25 tons ha−1 was used. There are eight treatments, i.e., burn (sugarcane straw burned after application), 50% (sugarcane straw at 312 g m−2 application), 75% (sugarcane straw at 468 g m−2 application), 100% (sugarcane straw at 625 g m−2 application), 50% + F (50% + recommended fertilizer application (4.7-g N m−2, 2.1-g P m−2 and 3.9-g K m−2)), 75% + F, 100% + F and 100% + U (100% + dissolved urea at the rate of 1.44-g N m−2). The litter bag and soil were sampled at 1, 2, 4, 8, 16, 24 and 32 weeks after sugarcane straw application. Our study revealed that sugarcane straw at a rate of 50% (312 g m−2) provided greatest N source efficiency, while such a removal rate together with chemical fertilizer (recommended rate) application not only enhanced mineral N, microbial biomass C and microbial biomass N but also accelerated sugarcane straw decomposition and led to nutrient (N, P and K) release. Thus, this practice can be a promising sugarcane straw removal approach for sustainable sugarcane production systems.