Predicting the harvest date of silage maize based on whole crop or cob dry matter contents

摘要

In Germany, it is recommended to harvest silage maize at a whole-crop dry matter (DM) content (GTS) of 32 to 36% and a cob DM content (KTS) of about 55%. Predicting harvest date maybe challenging for sites with a high risk of summer drought. Harvesting silage maize at the optimum stage of development is a prerequisite for maximising yield, forage quality and resource-use efficiency. 'This is especially challenging for sites that have frequent summer droughts, which cause fast maturation of the stover. The objectives of the current study were to evaluate the predicting ability of three modelling approaches: the semi-mechanistic MaisProg model, simulating GTS and KTS, and a temperature-sum driven tool (PAGF) predicting KTS. The study was based on an 8-year field experiment, conducted at Paulinenaue, northeastern Germany, where maize hybrids were harvested weekly from August until silage maturity. The results revealed that, under conditions of frequent summer droughts, MaisProg-GTS seems less suitable, as indicated by an unsatisfactory correlation coefficient (0.68). Better model fit was achieved by the KTS-based approaches (MaisProg: 0.92, PAGF: 0.96). In particular, PAGF sh owed a higher correlation for early harvest date predictions (mid/late August), which is advantageous in terms of arranging the hiring of contractors.