اثرات مدیریت برداشت بر رشد و نمو گیاه نیشکر، عملکرد و دوچرخه سواری مواد مغذی در فلوریدا و کاستاریکا

The literature on harvest management in Australia, Brazil and Louisiana indicates positive effects of harvest residue on sugarcane (Saccharum spp. hybrid) growth in well-drained soils with dry climate or high slopes, but negative effects in wet climates and heavy soils with little relief. There is limited information available on harvest management effects in Florida and Costa Rica. Therefore, sugarcane harvest management effects were studied on plant cane and two ratoon crops grown on organic Histosols in Florida and plant cane and three ratoon crops grown on clay loam soils in Costa Rica. The harvest systems included burnt cane harvest (Burnt), green cane harvest (Green), and green cane harvest with residue management. Residue management included either raking residues from the cane rows into the inter-row spaces (Rake; in Florida) or manual removal from the field (Remove; in Costa Rica) immediately after harvest. Sub-treatments were early (Nov.–Dec.) or late (Feb.–Mar.) harvest in Florida. Our results showed a negative effect from maintaining the harvest residue layer on late (>120 days after harvest, DAH) tillering and mid-season (150–200 DAH) leaf area index (LAI) in early harvested cane in Florida. However, the harvest system effects on early to mid season growth were not observed in final sugarcane yield (tons of cane per hectare, TCH), sucrose concentration (commercially recoverable sucrose, CRS) and sugar yield (tons of sugar per hectare, TSH) in Florida. In Costa Rica, TCH and TSH were greater in burnt than remove treatment with no difference between burnt and green. These results indicate that keeping harvest residue on soil surface after green cane harvest may have neutral effects on sugarcane yields in Florida and Costa Rica.